Technical field

The disclosure relates to the valorisation of methane-comprising streams into light olefins, for example, propylene, via an oxychlorination process. In particular, it relates to a process for the conversion of alkyl halides into light olefins like ethylene and propylene.

Background

Large quantities of methane are available worldwide but they are difficult and costly to transport due to their low energy density. Additionally, methane has a market value of fuel whereas other components such as ethylene and propylene have a higher value. Many attempts were made to convert methane into more valuable products or into products that are easier to transport.

The transformation of methane has been abundantly studied in the literature. The most common applied technologies imply the formation of synthesis gas (CO + H ₂ ) followed by its conversion of liquid hydrocarbons or to methanol, which could be further converted to olefins (MTO). These approaches remain expensive and alternative ways of methane activation and conversion have recently regained interest. Another transformation like the oxidative coupling of methane (OCM) or dehydroaromatization (DHA), meet serious limitations in scaling up and process optimization is required for industrial feasibility.

In modern circumstances, the demand for light olefins, i.e. ethylene, propylene and butylene is expected to grow continuously; thus, a need exists for an economic process for the conversion of methane and other light alkanes found in various gas feeds to olefins which have an increased value and are more economically transported which will contribute to the development of remote natural gas reserves.

However, the above-described processes, like the OCM process, have several disadvantages. The selectivity of this reaction is relatively low. The ethylene produced is indeed much more reactive than methane, and decent selectivity can only be obtained at low methane conversion. The reaction also needs to be conducted at high temperature implying that it is necessary to have a catalyst with high thermal stability.

Consequently, other routes were studied to convert methane into ethylene. In particular, oxidative routes, wherein a small amount of carbon only is lost, are very promising routes. In particular, processes involving the following equation reaction are particularly interesting:

CH4 + 2HCI + 0 ₂ 2CH3CI + 2H2O 2CH3CI -CH ₂ - + 2HCI The prior art describes various possible catalysts to convert alkyl halides like CH ₃ CI into light olefins like ethylene and propylene.

WO 2017/065944 describes a SAPO-34 molecular sieve having platelet morphology with the thickness of the platelet being less than 20 nm.

WO 2017/034842 describes the conversion of chloromethane into olefins on a chabazite zeolite. The stream is constituted of alkyl halide substantially free of oxygenates and the operating conditions allow the production of C2-C4 olefins.

WO 2016/099775 describes the use of a SAPO having the chabazite structure for the production of olefins from an alkyl halide and with the following formula (Si _x Al _y P _z )0 ₂ where x, y and z represent the mole fractions of Si, Al and P respectively, x is 0.01 to 0.30 and the sum of x + y + z is 1 and where the silicon tetrahedral oxides are connected with three or less aluminium tetrahedral oxides as shown by ²⁹ Si magic angle spinning (MAS) nuclear magnetic resonance (NMR) with peak(s) maxima between -93 ppm and -115 ppm.

WO 2016/022340 discloses a method for converting an alkyl halide to an olefin with a SAPO catalyst wherein the SAPO catalyst has bimodal acidity designated as weak acid sites and strong acid sites. The weak acid concentration is less than 0.55 mmol/g-cat and the total acid concentration is less than 1.5 mmol/g-cat.

The study of Shalygin A. et al., entitled “Light olefins synthesis from C1-C2 paraffins via oxychlorination processes ” ( Chem . Sci. Eng., 2013, 7(3), 279-288) concerns a methane oxychlorination using a reaction mixture containing 50% of methane, 20% of HCI and 10% of oxygen. Said mixture was contacted with a catalyst K4RuOCIio/TiC>2 at a temperature ranging between 300°C and 400°C. Methyl chloride was thus formed. Upon providing a second catalyst, different from K4RUOCI10/T1O2, it is possible to produce light olefins. The second catalyst can be one or more zeolites such as ZSM-5 (from the MFI family) or SAPO-34 (from CHA family).

The documents available disclose the conversion of alkyl halides into olefins. There is however a need for the direct conversion of methane into olefins. There is still a need for an overall process for the conversion of methane into olefins with acceptable overall yields. There is also a need for an overall process for the conversion of methane into olefins with acceptable overall yields wherein the selectivity to propylene and butylene is favoured.

Summary

The present disclosure aims to provide a simple and economic preparation process for producing light olefins, for example, propylene.

In a first aspect, an object of the disclosure is a process for the conversion of methane into olefins, comprising the following steps: e) providing a catalyst composition and putting in contact a stream comprising methyl chloride with a catalyst composition under second reaction conditions to produce a third stream comprising olefins and hydrogen chloride; f) recovering the third stream; g) optionally converting the third stream into a light olefin-enriched stream (21, 27); remarkable in that the process further comprises the steps of a) providing a first stream containing 5 to 80 mol % of methane (ChU) based on the total molar content of the first stream, at least 10 mol % of hydrogen chloride (HCI) based on the total molar content of the first stream and at least 1 mol % of dioxygen (O2) based on the total molar content of the first stream; b) providing a first catalyst composition; c) putting in contact the first stream with the first catalyst composition under first reaction conditions to produce a second stream comprising methyl chloride; d) optionally removing the water from the second stream if any; and in that said second stream comprising methyl chloride used in step e) is the second stream comprising methyl chloride obtained at step c) or optionally at step d), and in that the catalyst composition of step e) is a second catalyst composition that is or comprises one or more AEI zeolites; with preference, the process is devoid of a separation step other than the optional step d) between the step c) and e).

Surprisingly, it has been found a process in which it is possible to transform directly methane into olefins, without isolating the intermediate methyl chloride which is formed. The process is particularly advantageous in that methane can be used without further treatment in a single process to afford highly valuable olefins. Elevated conversions into olefins can be obtained by using the process of the present disclosure.

Preferentially, the process of the first aspect is a process for the conversion of methane into ethylene, propylene, butylene, or any mixtures thereof. Advantageously, the ethylene produced by the process of the first aspect is used in a polymer plant to produce polyethylene and/or the propylene produced is used in a polymer plant to produce polypropylene.

In a first alternative, for example, a step (h) of removing the hydrogen chloride from the third stream is performed to recover a hydrogen chloride-free stream. With preference, said step (h) is followed by a step (i) of removing unreacted methane and/or unreacted methyl chloride from said hydrogen chloride-free stream, to produce respectively a stream of unreacted methane and/or unreacted methyl chloride, said stream of unreacted methyl chloride being optionally redirected into step (e).

In a second alternative, for example, a step (h) of removing the hydrogen chloride from the olefin-enriched stream from said step (g) is carried out to recover a hydrogen chloride-free stream. With preference, said step (h) is followed by a step (i) of removing unreacted methane and/or unreacted methyl chloride from said hydrogen chloride-free stream, to produce respectively a stream of unreacted methane and/or unreacted methyl chloride, said stream of unreacted methyl chloride being optionally redirected into step (e).

In a third alternative, for example, the optional step (g) of converting the third stream into an olefin-enriched stream is carried out on the hydrogen chloride-free stream obtained after having removed the hydrogen chloride from the third stream. Wth preference, said step (g) is followed by a step (i) of removing unreacted methane and/or unreacted methyl chloride from said hydrogen chloride-free stream, to produce respectively a stream of unreacted methane and/or unreacted methyl chloride, said stream of unreacted methyl chloride being optionally redirected into step (e).

Whichever the alternative is chosen, one or more of the following features can be used to better define the first stream used in the inventive process:

- The molar concentration in the first stream of methane (ChU) is at least 20 mol % based on the total molar content of the first stream, preferably 50 mol %.

- The molar concentration in the first stream of hydrogen chloride (HCI) is at least 15 mol % based on the total molar content of the first stream, preferably 20 mol %.

- The molar concentration in the first stream of dioxygen (O2) is at least 5 mol % based on the total molar content of the first stream, preferably 10 mol %.

- The first stream comprises ethane, propane, butane or other hydrocarbons at a maximum concentration of 60 mol % based on the total molar content of the first stream, preferably of 65 mol %, more preferably of 70 mol%, even more preferably of 75 mol%.

- The first stream comprises less than 0.01 mol % of water based on the total molar content of the first stream, preferably the first stream is free of water.

- The first stream comprises less than 0.01 mol % of sulphur compounds based on the total molar content of the first stream, preferably the first stream is free of sulphur compounds. - The first stream originates from a flare gas stream of an oil-gas extraction and/or of refineries and/or of chemical plants and/or of the coal industry and/or of landfills and/or from a pre-treated natural gas of a natural gas reservoir.

One or more of the following features can be used to better define the first reaction conditions used in step (c) of the inventive process:

- The first reaction conditions comprise a temperature ranging from 200°C to 700°C, preferably from 250°C to 650°C, more preferably from 300°C to 600°C, even more preferably from 350°C to 550°C.

- The first reaction conditions comprise a pressure ranging from 0.2 MPa to 20 MPa, preferably from 0.5 MPa to 18 MPa, more preferably from 1 MPa to 16 MPa.

- The first reaction conditions comprise a weight hourly space velocity of at least 0.5 h ¹ , preferably of at least 1.0 h ¹ , more preferably of at least 5.0 h ¹ , even more preferably of at least 10.0 h ¹ .

- The first reaction conditions comprise a weight hourly space velocity between 0.5 h ¹ and 100 h ¹ , preferably comprised between 1.0 h ¹ and 15 h ¹ , more preferably comprised between 1.5 h ¹ and 10 h ¹ , even more preferably comprised between 2.0 h 1 and 6.0 h ¹ .

For example, the first catalyst composition comprises titanium phosphate, cobalt phosphate, vanadium phosphate, copper phosphate, manganese phosphate, nickel phosphate, chromium phosphate, iron phosphate, CeC>2, (VO)2P2C>7, T1O2, EuOCI, ZrC>2, SnC>2, AI2O3, S1O2, CuCh, RUC>2, UO3, UO2, UO, U3O5, U2O5, U3O7, U3O8, U4O9, uranium oxychlorides, sulphated oxides, ruthenium oxychlorides, TiC, WC, BC, BN, SiN, or any mixtures thereof. For example, the first catalyst composition comprises CeC>2, ZrC>2, UO ₂ , or T1O ₂ or any mixtures thereof.

For example, the first catalyst composition is deposited on a support. For example, the support is chosen among silica, alumina, titanium dioxide, tin dioxide, zirconium dioxide, or cerium dioxide.

For example, the first catalyst composition is treated with an acidic solution before step (c). For example, the acidic solution is a sulphuric acid solution and/or the acidic solution has a concentration ranging from 0.1 M to 18.4 M.

One or more of the following features can be used to better define the second reaction conditions used in step (e) of the inventive process: - The second reaction conditions comprise a temperature ranging from 200°C to 600°C, preferably from 350 to 550 °C.

- The second reaction conditions comprise a pressure ranging from 0.2 MPa to 20 MPa.

- The second reaction conditions comprise a weight hourly space velocity of at least 0.5 h ¹ , preferably of at least 1.0 h ¹ , more preferably of at least 5.0 h ¹ , even more preferably of at least 10.0 h ¹ .

- The second reaction conditions comprise a weight hourly space velocity between 0.5 h ¹ and 100 h ¹ , preferably comprised between 1.0 h ¹ and 15 h ¹ , more preferably comprised between 1.5 h ¹ and 10 h ¹ , even more preferably comprised between 2.0 h 1 and 6.0 h ¹ .

In a first embodiment, the second catalyst composition is not the same as the first catalyst composition.

In this case, one or more of the following features can be used to better define the second catalyst composition used in step (e) of the inventive process:

- The second catalyst composition comprises one or more AEI zeolites and one or more zeolites selected from the group of BEA, CHA, EUO, FAU, FER, MEL, MFI, MOR, MRE, MTT, MWW and TON families; with preference, the second catalyst composition comprises one or more AEI zeolites and one or more zeolites are selected from the group of BEA, CHA, EUO, FAU, MEL, MFI, MOR, MTT and TON families, more preferably the second catalyst composition comprises one or more AEI zeolites and one or more zeolites are selected from the group of CHA, EUO, MFI, MTT and TON families, even more preferably the second catalyst composition comprises one or more AEI zeolites and one or more zeolites are selected from the group of CHA and MFI families.

- The second catalyst composition comprises one or more zeolites selected from the list of SSZ-39, ALPO-18, SAPO-34, ZSM-50, EU-1, ferrierite, FU-9, ZSM-35, ZSM-11, silicalite-2, boralite D, TS-2, SSZ-46, ZSM-5, silicalite-1, boralite C, TS-1, ZSM-48, ZSM-23, MCM-22, PSH-3, ITQ-1, MCM-49, ZSM-22, Theta-1, or NU-10 materials; with preference, the one or more zeolites are selected from SSZ-39, ALPO-18, SAPO-34, ZSM-50, EU-1, ZSM-11, silicalite-2, boralite D, TS-2, SSZ-46, ZSM-5, silicalite-1, boralite C, TS-1, ZSM-23, ZSM-22, Theta-1, or NU-10 materials; more preferably, the one or more zeolites are selected from SSZ-39, ALPO-18, SAPO-34, EU-1, ZSM-5, ZSM-23 or ZSM-22 materials. - The second catalyst composition comprises one or more zeolites selected from zeolites having pores sizes ranging from an 8-membered ring channel to a 10-membered ring channel.

- The second catalyst composition is subjected to a step of steaming before step (e). With preference, the step of steaming is carried out at a temperature ranging between 400°C and 1000°C, more preferably between 450°C and 950°C, even more preferably between 500°C and 900°C.

- The one or more zeolites of the second catalyst composition have a Si/AI molar ratio of at least 5, preferentially of at least 50, more preferentially of at least 100.

- The one or more zeolites of the second catalyst composition have a microporous crystalline framework substituted with one or more Lewis acid sites.

- The one or more zeolites of the second catalyst composition have at least one metal in the crystalline framework chosen from the list: Sn, Hf, Zn, Zr, Ti, V, Ta, Ga, Ge, Nb, Mo, Co, W and Cr.

For example, the content of the one or more AEI zeolites in the second catalyst composition is ranging from 40 to 100 wt.% based on the total weight of the second catalyst composition; preferably from 60 to 98 wt.%; even more preferably from 80 to 95 wt.%.

For example, the second catalyst composition comprises one or more AEI zeolites and one or more MFI zeolites; wherein the content of the one or more AEI zeolites in the second catalyst composition is ranging from 40 to 98 wt.% based on the total weight of the second catalyst composition; preferably from 60 to 98 wt.%; even more preferably from 80 to 95 wt.%.

For example, the second catalyst composition comprises one or more AEI zeolites and one or more CHA zeolites; wherein the content of the one or more AEI zeolites in the second catalyst composition is ranging from 40 to 98 wt.% based on the total weight of the second catalyst composition; preferably from 60 to 98 wt.%; even more preferably from 80 to 95 wt.%.

For example, the second catalyst composition comprises one or more AEI zeolites and one or more CHA zeolites and one or more MFI zeolites; wherein the content of the one or more AEI zeolites in the second catalyst composition is ranging from 40 to 98 wt.% based on the total weight of the second catalyst composition; preferably from 60 to 98 wt.%; even more preferably from 80 to 95 wt.%.

For example, the second catalyst composition comprises one or more AEI zeolites and one or more CHA zeolites and the second reaction conditions comprise a temperature ranging from 350°C to 450°C. For example, the second catalyst composition comprises one or more AEI zeolites and one or more MFI zeolites and the second reaction conditions comprise a temperature ranging from 280°C up to 350°C.

For example, the second catalyst composition comprises one or more MFI zeolites; wherein MFI zeolites are one or more metal-containing MFI zeolites selected from molybdenum- containing MFI zeolites, tin-containing MFI zeolites, vanadium-containing MFI zeolites, tungsten-containing MFI zeolites and iron- containing MFI zeolites. With preference, the one or more metal-containing MFI zeolites are one or more selected from metal-containing ZSM-5 and metal-containing silicalite-1.

For example, the second catalyst composition is or comprises one or more AEI zeolites with a Si/AI molar ratio ranging from 5 to 200; with preference, the second catalyst composition is or comprises SSZ-39.

For example, the second catalyst composition is different from the first catalyst composition; and the first catalyst composition comprises CeC>2, ZrC>2, UO2, or T1O2 or any mixtures thereof, and the second catalyst composition comprises one or more AEI zeolites and one or more zeolites selected from zeolites having pores sizes ranging from an 8-membered ring channel to a 10-membered ring channel; with preference, the second catalyst composition is one or more AEI zeolites or comprises one or more AEI zeolites and one or more zeolites selected from the group of CHA, EUO, MFI, MTT and TON families.

For example, step (g) of converting the third stream into a light olefin-enriched stream comprises the following sub-steps: i. providing a third catalytical composition comprising at least one cracking catalyst and/or a fourth catalytical composition comprising at least one metathesis catalyst; ii. putting into contact the third stream with the third catalytical composition under third reaction conditions and/or with the fourth catalytical composition to recover an olefin- enriched stream.

Wth preference, the third catalytical composition comprises at least one cracking catalyst which comprises one or more zeolites and/or one or more clays. Wth preference, said at least one cracking catalyst comprises one or more zeolites selected from silicalites from the MFI family, crystalline silicate from the MFI family with a Si/AI atomic ratio of at least 180, crystalline silicate from the MEL family with a Si/AI atomic ratio ranging between 150 and 800, and/or phosphorous-modified zeolite from the MFI, MEL, FER, or MOR family. With preference, said at least one cracking catalyst comprises one or more zeolites selected from silicalites from the MFI family, optionally with a silica binder.

For example, the process is remarkable in that the third reaction conditions comprise

- a temperature ranging from 400°C to 600°C, preferably ranging from 425°C to 575°C, more preferably ranging from 450°C to 550°C; even more preferably from 475°C to 525°C; and/or

- a weight hourly space velocity comprised between 0.1 h ¹ and 100 h ¹ , preferably comprised between 1.5 h ¹ and 10 h ¹ ; and/or

- a pressure ranging between 0.5 MPa and 1.5 MPa, preferentially between 0.6 MPa and 1.0 MPa.

Wth preference, said fourth catalytical composition comprises at least one metathesis catalyst which comprises one or more oxides of group VIA metal and/or VIIA metal, preferably molybdenum oxides, tungsten oxides, and/or rhenium oxides. Wth preference, said metathesis catalyst comprises one or more cobalt oxides. Wth preference, said one or more oxides of group VIA metal and/or VIIA metal are present in an amount ranging between 0.1 and 50 wt.% of the second catalyst composition, more preferably between 0.5 and 30 wt.%, even more preferably between 1 and 20 wt.%.

Wth preference, said fourth catalytical composition further comprises an isomerization catalyst, said isomerization catalyst preferably comprising hydrotalcite and/or one or more oxides of alkali metal, alkaline earth metal, group lib and/or group Ilia of the periodic table.

Wth preference, said fourth catalytical composition comprises an heterogeneous support, with preference, said heterogeneous support is alumina, silica and/or zeolites.

In a second aspect, an object of the present disclosure is an installation to conduct a process for the conversion of methane into olefins according to the first aspect, the installation comprising a first reaction zone comprising a first reactor loaded with at least one first catalytic bed; a second reaction zone comprising a second reactor wherein said second reaction zone is downstream of the first reaction zone, wherein the second reactor is loaded with at least one second catalytic bed; an optional water-removal unit between the first reaction zone and the second reaction zone; optional lines to direct at least part of a stream exiting the second reaction zone to a separation unit; the installation is remarkable in that the stream exiting the first reaction zone is directly conveyed into the second reaction zone, optionally through the water-removal unit when the water-removal unit is present.

In a preferred embodiment, the separation unit, when present, comprises at least a water stripper system and a demethanizer.

With preference, the demethanizer comprises a CFU-recycling line directed to the first reaction zone.

Wth preference, said separation unit further comprises an extractive distillation system downstream of said water stripper system. Wth preference, the extractive distillation system comprises an HCI-recycling line directed to the first reactor.

For example, said installation further comprises a third reaction zone downstream of said second reaction zone and upstream of said separation unit when said separation unit is present, the third reaction zone comprising at least one cracking reactor.

For example, said installation further comprises a third reaction zone downstream of said second reaction zone and upstream of said separation unit when said separation unit is present, the third reaction zone comprising at least one metathesis reactor

For example, said installation further comprises a fourth reaction zone within said separation unit when said separation unit is present, the fourth reaction zone comprising at least one cracking reactor.

For example, said installation further comprises a fourth reaction zone within said separation unit when said separation unit is present, the fourth reaction zone comprising at least one metathesis reactor.

Definitions

Wthin the meaning of the present disclosure, the term "conversion" means the mole fraction (i.e. , per cent) of a reactant converted to a product or products. The term "selectivity" refers to the per cent of converted reactant that went to a specified product, for example, C2- C4 olefin selectivity is the % of alkyl halide that formed C2-C4 olefins. The terms "wt.%", "vol.%", or "mol.%" refers to a weight, volume, or molar percentage of a component, respectively, based on the total weight, the total volume of material, or total moles, that includes the component. In a non-limiting example, 10 grams of the component in 100 grams of the material is 10 wt. % of the component.

Zeolite codes (e.g., CHA...) are defined according to the “Atlas of Zeolite Framework Types", 6 ^th revised edition, 2007, Elsevier, to which the present application also refers.

The terms “olefin” or “alkene” as used herein relate to an unsaturated hydrocarbon compound containing at least one carbon-carbon double bond.

The terms “mono-olefin” as used herein relates to an unsaturated hydrocarbon compound containing one single carbon-carbon double bond.

The SAR of one or more zeolites refers to the silicon to aluminium molar ratio of the one or more zeolites. SAR is determined by NH3-Temperature Programmed Desorption.

As used herein, the term “C# hydrocarbons”, wherein “#” is a positive integer, is meant to describe all hydrocarbons having # carbon atoms. C# hydrocarbons are sometimes indicated as just C#. Moreover, the term “C#+ hydrocarbons” is meant to describe all hydrocarbon molecules having # or more carbon atoms. Accordingly, the expression “C5+ hydrocarbons” is meant to describe a mixture of hydrocarbons having 5 or more carbon atoms.

The symbol “=” in the term “C#= hydrocarbon” indicates that the hydrocarbon concerned is an olefin or an alkene, the notation “=” symbolizing the carbon-carbon double bond. For instance, “C6=” stands for “C6 olefin”, or for “olefins comprising 6 carbon atoms”.

The term “steam” is used to refer to water in the gas phase, which is formed when water boils.

The terms "comprising", "comprises" and "comprised of as used herein are synonymous with "including", "includes" or "containing", "contains", and are inclusive or open-ended and do not exclude additional, non-recited members, elements or method steps. The terms "comprising", "comprises" and "comprised of" also include the term “consisting of”.

The recitation of numerical ranges by endpoints includes all integer numbers and, where appropriate, fractions subsumed within that range (e.g. 1 to 5 can include 1, 2, 3, 4, 5 when referring to, for example, a number of elements, and can also include 1.5, 2, 2.75 and 3.80, when referring to, for example, measurements). The recitation of endpoints also includes the recited endpoint values themselves (e.g. from 1.0 to 5.0 includes both 1.0 and 5.0). Any numerical range recited herein is intended to include all sub-ranges subsumed therein. The particular features, structures, characteristics or embodiments may be combined in any suitable manner, as would be apparent to a person skilled in the art from this disclosure, in one or more embodiments.

Description of the figures

Figure 1 describes a first embodiment of the installation of the present disclosure. Figure 2 describes a second embodiment of the installation of the present disclosure. Figure 3 describes a third embodiment of the installation of the present disclosure. Figure 4 describes a simplified scheme of possible extractive HCI rectification.

Figure 5 describes a temperature program desorption (TPD) analysis of the catalysts. Figure 6 shows the characterizations of (a) MoMFI-1, (b) MoMFI-2, (c) SnMFI, and (d) SiMFI by Scanning electron microscopy (SEM). The crystal size and morphology correspond to the one from purely siliceous MFI zeolite (silicalite-1) that would be obtained by using the same synthesis procedure without the addition of Molybdenum (Figure 6d). This obtained crystal size (around 150 nm diameter) is approximately twice smaller than the size that would be obtained by using a normal direct synthesis approach from the same gel composition with molybdenum (around 300 nm).

Figure 7 shows the characterizations of MoMFI-1, MoMFI-2, SnMFI, and SiMFI by powder X-ray diffraction (XRD) in the range 3 to 40° 2Q. Only Bragg peaks corresponding to MFI structure are present in all zeolite materials, more specifically, only peaks corresponding to the monoclinic MFI unit cell are observed when it would be expected to have orthorhombic symmetry if only purely siliceous MFI was to be obtained. The monoclinic symmetry can be easily evidenced by the splitting of some diffraction peaks (mainly at 23.30°, 23.75°, and 24.50° 2Q). Moreover, an expansion of unit cell volume was observed for all samples once compared to purely siliceous silicalite-1 zeolite. Both observations are indicating the presence of heteroatoms (Mo or Sn) in the framework of the MFI structure. Details of the Le Bail profile refinement fits are presented in Table 1.

Table 1

Table 1 (sequel) ^a Goodnes Of Fit ^b Expected R-factor ^c Weight Profile R-factor

Table 1 showing the Le Bail profile refinement results (unit cell parameters, and refinement values) for MoMFI-1 , MoMFI-2, SnMFI, and SiMFI examples. Samples used for Le Bail refinement were recorded from 3 to 80 ° 2Q for 10h.

Figure 8 shows the X-ray diffraction patterns of the samples MoM FI-3, VMFI-1 , VM FI- 2, VMFI-3, and VMFI-4. All samples exhibit splitting of diffraction peaks (mainly at

23.30, 23.75, and 24.50 ° 2Q) linked to a monoclinic symmetry, indicative of an effective metal introduction, and healing of silanol defects.

- Figure 9 shows ²⁹ Si MAS NMR spectra of MoMFI-1, MoMFI-2, SnMFI, and SiMFI samples. The absence of Q3 species and high resolution of Q4 species was obtained indicating the very low amount of silanol defects in the metal-containing samples, and the local homogeneity of the samples, with regards to purely siliceous MFI zeolite (sample SiMFI)

Figure 10 represents the { ¹ H} ²⁹ Si CP MAS NMR experiment for sample MoMFI-1, SnMFI, and SiMFI, where the absence/negligible amount of silanols is demonstrated through the absence of any signal for both metal-containing samples with regards to sample SiMFI.

Figure 11 shows the Raman spectroscopy of SiMFI, MoMFI-1, MoMFI-2 and SnMFI. The absence of any metal oxide phase is confirmed for all samples. New contributions at 332, 416, 803, and 820 cm ^-1 indicate the presence of framework metal species. The low amount of silanol defects can also be observed by the absence of a signal at about 980 cm ^-1 for metal-containing zeolites. No peaks corresponding to the oxide phase of molybdenum (higher intensity band expected at 980 cm ^-1 ) or tin (higher intensity band expected at 632 cm ^-1 ) can be observed, indicating the absence of oxide species in both samples.

Figure 12 shows the solid-state nuclear magnetic resonance of phosphorus ( ³¹ P MAS NMR spectra) of TMPO interacting with MoMFI-1 sample. Two peaks can be observed at 29 and 44 ppm, corresponding to respectively: physiosorbed TMPO and TMPO interacting with Lewis acid sites from the MFI zeolite, which are actual Mo framework sites.

- Figure 13 shows the STEM-EDS of MoMFI-1: (a) STEM, (b) Mo, (c) Si and (d) O. The homogeneous distribution of Mo in the MFI framework is shown.

Figure 14 shows a high-resolution HAADF-STEM image of sample MoMFI-1. The Z- sensitive contrast obtained using this imaging technique allows observing the presence of the Mo metal sites in the structure. Mo appears as white dots, some of them being highlighted with red circles in the figure. Due to the location and size of these sites, it can be concluded that Mo atoms are atomically dispersed in the zeolite MFI framework. Figure 15 shows the XRD pattern of sample MoMFI-4.

Figure 16 shows the SEM picture of sample MoMFI-4.

Figure 17 shows the ²⁹ Si MAS NMR and ²⁹ Si CP MAS NMR spectra of sample MoMFI- 4.

Figure 18 shows the XRD pattern of the as-obtained sample Mo-Silicalite-1. Splitting of diffraction peaks at 23.30, 23.75, and 24.50 ° 2Q is observed and indicates a monoclinic symmetry of the MFI structure instead of the orthorhombic cell. Details of the Le Bail profile refinement fits are presented in Table 2.

Table 2 Table 2 (sequel) ^a Goodnes Of Fit ^b Expected R-factor ^c Weight Profile R-factor

Additionally, using Le Bail profile refinement of the diffraction pattern (Table 2), the space group transition towards monoclinic symmetry was confirmed, alongside a unit cell volume expansion at 5377.1 A ³ (to be compared with a volume of average 5330.0 A ³ for purely siliceous MFI (Silicalite-1) zeolite). Both observations indicate the successful introduction of Mo atoms in the Silicalite-1 structure.

Figure 19 shows the SEM picture of the as-obtained sample Mo-Silicalite-1. Particles of approximately 100 to 150 nm are obtained.

Figure 20 shows the (a) ²⁹ Si MAS and the (b) { ¹ H} ²⁹ Si CP MAS NMR spectra of the as- obtained sample Mo-Silicalite-1. No signal is observed on the cross-polarization experiment, indicative of the absence of any silanol species for this sample. This is further supported by the absence of Q3 species in the ²⁹ Si MAS NMR spectrum. Additionally, a very high resolution of the Q4 species is achieved, indicative of the very high local homogeneity of the sample, and the absence of silanol defects.

Figure 21 shows the XRD pattern of the as-obtained sample Mo-ZSM-5. Splitting of diffraction peaks at 23.30, 23.75, and 24.50 °20 is observed indicating the transformation from orthorhombic to monoclinic symmetry of the sample. Details of the Le Bail profile refinement fits are presented in Table 3.

Table 3

Table 3 (sequel) ^a Goodnes Of Fit b Expected R-factor c Weight Profile R-factor

Also, using Le Bail profile refinement of the following XRD pattern (Table 3), the space group transition towards monoclinic symmetry is confirmed, and expansion of the unit cell volume with regards to the initial material from 5353.81 to 5369.27 A ³ is measured. The higher unit cell volume of the initial ZSM-5 sample used in the preparation of Mo- ZSM-5 is attributed to the presence of aluminium

Figure 22 shows the (a) ²⁹ Si MAS and the (b) { ¹ H} ²⁹ Si CP MAS NMR spectra of the as- obtained sample Mo-ZSM-5. The absence of any silanol species for this sample is confirmed: no peaks corresponding to Q2 and Q3 are present in the { ¹ H} ²⁹ Si CP MAS NMR spectrum (Fig. 22). Additionally, the Q4 species are present with high resolution indicating the high local homogeneity of the sample, and the absence of silanol defects, as they are cured by the addition of Mo.

Figure 23 shows ¹ H MAS NMR of dehydrated zeolite samples silicalite-1, Mo-silicalite- 1 , ZSM-5 and Mo-ZSM-5.

Detailed description

The disclosure concerns a process for the production of light olefins and the installation thereof that will be described jointly in reference to figures 1 to 3.

According to the disclosure, the process for the production of light olefins comprises the following steps: e) providing a catalyst composition and putting in contact a stream 7 comprising methyl chloride with a catalyst composition under second reaction conditions to produce a third stream 11 comprising olefins and hydrogen chloride; f) recovering the third stream 11 ; g) optionally converting the third stream 11 into a light olefin-enriched stream (21 , 27); remarkable in that the process further comprises the steps of a) providing a first stream 3 containing 5 to 80 mol % of CFU based on the total molar content of the first stream 3, at least 10 mol % of HCI based on the total molar content of the first stream 3 and at least 1 mol % of O2 based on the total molar content of the first stream 3; b) providing a first catalyst composition; c) putting in contact the first stream 3 with the first catalyst composition under first reaction conditions to produce a second stream 7 comprising methyl chloride; d) optionally removing the water from the second stream if any; in that the stream 7 comprising methyl used in step e) is the second stream 7 comprising methyl chloride obtained at step c) or optionally at step d), and in that the catalyst composition of step e) is a second catalyst composition that is or comprises one or more AEI zeolite; with preference, the process is devoid of a separation step other than the optional step d) between the step (c) and (e).

In other words, the process for the conversion of methane into olefins is comprising the following steps: a) providing a first stream 3 containing 5 to 80 mol % of CFU based on the total molar content of the first stream 3, at least 10 mol % of HCI based on the total molar content of the first stream 3 and at least 1 mol % of O2 based on the total molar content of the first stream 3; b) providing a first catalyst composition and a second catalyst composition; c) putting in contact the first stream 3 with the first catalyst composition under first reaction conditions to produce a second stream 7 containing methyl chloride; d) optionally removing the water from the second stream 7 if any; e) putting in contact the second stream 7 with the second catalyst composition under second reaction conditions to produce a third stream 11 containing olefins and hydrogen chloride; f) recovering the third stream 11 ; g) optionally converting the third stream 11 into an olefin-enriched stream (21 , 27); wherein between the step (c) and (e) no further separation step is performed apart from the optional step (d) and wherein the second catalyst composition provided in step (b) is or comprises one or more AEI zeolites.

Figure 1 describes the installation 1 that can be used to carry out the above-mentioned process. Installation 1 comprises a first reaction zone 5 comprising a first reactor which is loaded with at least one first catalytic bed. For example, the first reactor is an oxyhalogenation reactor. The first catalyst composition on the first catalytic bed converts the first stream 3 into a second stream 7 comprising among others methyl chlorides. The second stream 7 is directed into a second reaction zone 9 comprising a second reactor, optionally through a water-removal unit (not shown). For example, the second reactor is a synthesis reactor. The second reactor is thus downstream of the first reactor and is loaded with at least one-second catalytic bed. The second catalyst composition on the second catalytic bed converts the second stream 7 into a third stream 11 comprising among others olefins, for example, ethylene, propylene, butylene, or any mixtures thereof. Advantageously, the third stream 11 is conveyed into a separation unit 29, which comprises at least a water stripping system 25 and a demethanizer 13. The third stream 11 is passed through the water stripping system 25 to produce a fourth stream 31 that can be directed into the demethanizer 13. From the water stripping system 25, it is possible to recover an effluent 33 comprising hydrogen chloride and water.

As shown in figure 1 , in the separation unit 29, the water stripping system 25 is placed upstream of a demethanizer 13. The effluent 33 comprising hydrogen chloride and water could then be directed into an extractive distillation system 35 to recover dry hydrogen chloride stream 37. Advantageously said dry hydrogen chloride stream 37 could be further recycled to the first reactor 5.

The fourth stream 31 , which is substantially free of hydrogen chloride, could optionally be then dried in a drier system (not shown) and directed into the demethanizer 13. The demethanizer 13 is used to remove the unreacted methane, carbon monoxide and some amounts of carbon dioxide that may be present in the fourth stream 31. Said unreacted methane could be further purified from carbon dioxide by techniques known in the art and directed to the first reactor 5 through the recycle line 15. Said methods for removal of carbon dioxide could be, for instance, caustic wash or amine wash. The presence of carbon monoxide and small amounts of carbon dioxide are not disturbing for the operation of the first reactor 5.

The fifth stream 17 which exits the demethanizer 13 comprises less than 0.01 mol% of methane-based on that total molar content of the third stream 11 or, preferably is free of methane. The fifth stream 17 comprises olefins and higher hydrocarbons, small amounts of unreacted methyl chloride and higher alkyl chlorides, and optionally alkyl dichlorides and trichloride and it could further be separated to isolate olefins, for example, in a de-ethanizer (not shown) that could be used for recovering a stream comprising substantially C2 products, ethylene and ethane. Said unreacted methyl chloride could be further conveyed to the second reaction zone 9.

Advantageously, at least part of said third stream 11 and/or fourth stream 31 could be directed back to said second reactor 9.

In another embodiment, the third stream 11 could be used as a feedstock for a further upgrade of the olefin composition before entering into the separation unit 29. The upgrade of the olefin composition can be obtained for example by achieving an olefin cracking process or a metathesis reaction. The presence of said alkyl chlorides and carbon dioxide is not disturbing for said olefin upgrading. This is depicted in figure 2, which shows that the third stream 11 could be directed into a third reaction zone 19 which is downstream of the second reaction zone 9 and upstream of the separation unit 29, in particular of the water stripping system 25, to produce a light olefin-enriched stream 21 comprising lighter olefins in comparison to the third stream 11. The olefin-enriched stream 21 can then be conveyed into the separation unit 29, and in particular into the water stripping system 25 to produce a fourth stream 39 which is substantially free of hydrogen chloride.

In yet another embodiment, the fourth stream 31 which is substantially free of hydrogen chloride could also be used as a feedstock for a further upgrade of the olefin composition once in the separation unit 29 and before entering the demethanizer 13. The upgrade of the olefin composition can be obtained for example by achieving an olefin cracking process or a metathesis reaction. The presence of said alkyl chlorides and carbon dioxide is not disturbing for said olefin upgrading. This is depicted in figure 3, which shows that the fourth stream 31 could be directed into a fourth reaction zone 23 which is downstream of the water stripping system 25 and upstream of the demethanizer 13 to produce an olefin-enriched stream 27 comprising lighter olefins in comparison to the fourth stream 31. The olefin-enriched stream 27 can then be conveyed into the demethanizer 13.

Advantageously, at least part of said olefin-enriched streams (21 , 27) could be directed back to said second reaction zone 9 or to said third reaction zone 19 or said fourth reaction zone 23, respectively.

In yet another embodiment (not shown), the installation could comprise both a third reaction zone which is downstream of the second reaction zone and upstream of the separation unit and a fourth reaction zone into the separation unit, said fourth reaction zone being is downstream of the water stripping system and upstream of the demethanizer.

The first catalyst composition

With regards to the first catalyst composition, it can comprise any catalyst suitable to perform the reaction of step (c), namely to convert a first stream comprising among others methane into a second stream comprising among others methyl chlorides. It is advantageous to use catalysts having very high activity and which allow the reaction to proceed at low temperature.

For example, the first catalyst composition comprises titanium phosphate, cobalt phosphate, vanadium phosphate, copper phosphate, manganese phosphate, nickel phosphate, chromium phosphate, iron phosphate, CeC>2, (VO)2P2C>7, T1O2, EuOCI, ZrC>2, SnC>2, AI2O3, S1O2, CuCh, RUC>2, UO3, UO2, UO, U3O5, U2O5, U3O7, U3O8, U4O9, uranium oxychlorides, sulphated oxides, ruthenium oxychlorides, TiC, WC, BC, BN, SiN, or any mixtures thereof; preferably, the first catalyst composition comprises Ce02, Zr02, UO ₂ , or T1O ₂ or any mixtures thereof.

In particular, the catalyst of the first catalyst composition can be selected from the group of titanium phosphate, cobalt phosphate, vanadium phosphate, copper phosphate, manganese phosphate, nickel phosphate, chromium phosphate, or iron phosphate. Such catalysts are described in the study of G. Zichittella et ai {ACS CataL, 2019, 9, 5772-5782).

The catalyst of the first catalyst composition can also be a CeC>2 catalyst as described in the study of Z. Vajglova et al. (J. CataL, 2019, 372, 287-298) or Ce0 ₂ , (nq) ₂ R ₂ 0 ₇ , Ti0 ₂ , EuOCI, FeP0 ₄ , or Mn ₃ (P0 ₄ ) as described in the study of G. Zichittella ( Energy Technol. 2019, 1900622).

The catalyst of the first catalyst composition can also be Ce0 ₂ , Zr0 ₂ , T1O ₂ , EU ₂ O ₃ , AI ₂ O ₃ or Ce0 ₂ deposited on various supports such as Zr0 ₂ , T1O ₂ or AI ₂ O ₃ using the method described in the study of M. Moser et al. (J. of CataL, 2015, 331, 128-137).

The catalyst of the first catalytical bed can also be chosen among TiC, WC, BC, BN, SiN and other similar compounds. A catalyst such as CuCh, RUO2 can also be used.

Other examples of suitable catalysts comprise at least one uranium compound, with preference with a carrier material, as disclosed in CN 106861707. Suitable carrier materials for the catalyst are, for example, silica, alumina (e.g., a-alumina, g-alumina or modifications), titanium dioxide (rutile, anatase, etc.), tin dioxide, zirconium dioxide, cerium dioxide or mixtures thereof. Suitable uranium compounds include uranium oxides, uranium chlorides and uranium oxychlorides. Suitable uranium oxides are, for example, UO ₃ , UO ₂ , UO or the results from the mixtures of nonstoichiometric phases such as U ₃ O ₅ , U ₂ O ₅ , U ₃ O ₇ , U ₃ O ₈ , and/or U ₄ O ₉ . These preferred catalysts comprising uranium oxide or a mixture of uranium oxide catalysts are particularly advantageous because, surprisingly, they have extremely high activity and stability for methane oxych I ori nation reaction.

In a preferred embodiment, the oxychloride compounds (UO _x Cl _y ) can be used as a precursor for the uranium oxides. The uranium compound can be used alone or together with further catalytically active components. Suitable further catalytically active components can be advantageously those selected from the list comprising ruthenium, osmium, rhodium, iridium, palladium, platinum, copper, silver, gold, rhenium, bismuth, cobalt, iron, antimony, tin, manganese, chromium, cerium and zirconium; preferably, from the list comprising ruthenium, gold, bismuth, cerium or zirconium; more preferably ruthenium. Also suitable are mixtures thereof, or chemical compounds comprising at least one of the above elements of the list. In a most preferred embodiment, ruthenium is used in oxidic form or as a chloride compound or oxychloride.

The catalysts described could be advantageously treated with an acidic solution such as a sulphuric acid solution or a hydrochloric acid solution, preferably with a sulphuric acid solution. For example, the acidic solution has a concentration ranging from 0.1 M to 18.4 M, preferably the concentration is ranging from 1 M to 6 M.

Yet other examples of suitable catalysts comprise at least one ruthenium compound, with preference with a carrier material, as disclosed in DE1567788, DE19734412, and DE19748299. This type of catalysts is comprising the active component of ruthenium oxide, ruthenium oxychloride or ruthenium described with the content of ruthenium of 0.01 wt.% to 20 wt.% supported on at least one carrier material. Suitable carrier materials are silica, alumina (e.g., a-alumina, g-alumina, or modifications), titanium dioxide (rutile, anatase, etc.), tin dioxide, zirconium dioxide, cerium dioxide, preferably titanium dioxide. In a preferred embodiment, titanium dioxide was used in the form of rutile as a carrier.

The second catalyst composition

The second catalyst composition is or comprises one or more AEI zeolites.

For example, the content of the one or more AEI zeolites in the second catalyst composition is at least 40 wt.% based on the total weight of the second catalyst composition; preferably, at least 50 wt.%; more preferably, at least 60 wt.%; even more preferably, at least 70 wt.%; most preferably, at least 80 wt.%; even most preferably, at least 90 wt.% or is 100 wt.%. The remaining (up to 100 wt.%) being one or more zeolites selected from the group of BEA, CHA, EUO, FAU, FER, MEL, MFI, MOR, MRE, MTT, MWW and TON families; with preference, one or more CHA zeolites.

For example, the content of the one or more AEI zeolites in the second catalyst composition is ranging from 40 to 100 wt.% based on the total weight of the second catalyst composition; preferably from 60 to 98 wt.%; even more preferably from 80 to 95 wt.%.

For example, the second catalyst composition comprises one or more AEI zeolites in a content ranging from 40 to 100 wt.% and one or more zeolites selected from the group of BEA, CHA, EUO, FAU, FER, MEL, MFI, MOR, MRE, MTT, MWW and TON families in a content ranging from 0 to 60 wt.%; the second catalyst composition comprises one or more AEI zeolites in a content ranging from 60 to 98 wt.% and one or more zeolites selected from the group of BEA, CHA, EUO, FAU, FER, MEL, MFI, MOR, MRE, MTT, MWW and TON families in a content ranging from 2 to 40 wt.%; more preferably, the second catalyst composition comprises one or more AEI zeolites in a content ranging from 5 to 20 wt.% and one or more zeolites selected from the group of BEA, CHA, EUO, FAU, FER, MEL, MFI, MOR, MRE, MTT, MWW and TON families in a content ranging from 0 to 60 wt.%.

For example, the second catalyst composition comprises one or more AEI zeolites and one or more MFI zeolites; wherein the content of the one or more AEI zeolites in the second catalyst composition is ranging from 40 to 98 wt.% based on the total weight of the second catalyst composition; preferably from 60 to 98 wt.%; even more preferably from 80 to 95 wt.%.

For example, the second catalyst composition comprises one or more AEI zeolites and one or more CHA zeolites; wherein the content of the one or more AEI zeolites in the second catalyst composition is ranging from 40 to 98 wt.% based on the total weight of the second catalyst composition; preferably from 60 to 98 wt.%; even more preferably from 80 to 95 wt.%.

For example, the second catalyst composition comprises one or more AEI zeolites and one or more CHA zeolites and one or more MFI zeolites; wherein the content of the one or more AEI zeolites in the second catalyst composition is ranging from 40 to 98 wt.% based on the total weight of the second catalyst composition; preferably from 60 to 98 wt.%; even more preferably from 80 to 95 wt.%.

When the second catalyst composition comprises one or more AEI zeolites and one or more other materials, it can comprise a fairly wide range of materials that have the common functionality of being acidic ion-exchangers. One type of suitable materials could contain a synthetic crystalline alumino-silicate oxide framework.

Thus, the second catalyst may consist of one or more AEI zeolites or may comprise one or AEI zeolites and one or more zeolites selected from the group of BEA, CHA, EUO, FAU, FER, MEL, MFI, MOR, MRE, MTT, MWW and TON families.

The below considerations regarding the crystalline alumino-silicate oxide framework and regarding the crystalline alumino-silicate catalyst may apply to the one or AEI zeolites and/or to one or more zeolites selected from the group of BEA, CHA, EUO, FAU, FER, MEL, MFI, MOR, MRE, MTT, MWW and TON families.

In certain embodiments, a portion of the aluminium in the crystalline alumino-silicate oxide framework is substituted with magnesium, boron, gallium, and/or titanium, preferentially with boron. In certain embodiments, a portion of the silicon in the crystalline alumino-silicate oxide framework is substituted with phosphorus. In certain embodiments, the alumino-silicate could contain tin, molybdenum, tungsten, or iron in the tetrahedral sites of the framework.

The crystalline alumino-silicate catalyst generally may have a significant anionic charge within the crystalline alumino-silicate oxide framework structure which may be balanced, for example, by cations of elements selected from the group H, Li, Na, K or Cs or the group Mg, Ca, Sr or Ba or the group La or Ce. Although zeolitic catalysts may be commonly obtained in a sodium form, a protonic or hydrogen form (via ion-exchange with ammonium hydroxide, and subsequent calcining) is preferred, or a mixed protonic/sodium form may also be used. The zeolite may also be modified by ion-exchange with alkali metal cations, such as Li, K, or Cs, with alkali-earth metal cations, such as Mg, Ca, Sr, or Ba, or with transition metal cations, such as Fe, Ni, Cu, Mn, V, W or with rare-earth metal cations, such as La or Ce. Such subsequent ion-exchange may replace the charge-balancing counter-ions, but furthermore may also partially replace ions in the oxide framework resulting in a modification of the crystalline make up and structure of the oxide framework.

The crystalline alumino-silicate or substituted crystalline alumino-silicate may include a microporous or mesoporous crystalline aluminosilicate, for example, a synthetic microporous crystalline zeolite. Moreover, the crystalline alumino-silicate or substituted crystalline alumino silicate, in certain embodiments, may be subsequently impregnated with an aqueous solution of an Mg, Ca, Sr, Ba, La or Ce salt. In certain embodiments, the salts may be phosphate salts.

The particular catalyst used in the second catalyst composition will depend, for example, upon the particular distribution of the olefins in the products that are desired and reactor type. AEI framework alumina-silicate is used to favor to produce C2-C3 olefins and a small amount of C5 products. CHA framework alumina-silicate can be used in combination with AEI framework alumina-silicate for the same purpose. However, when some C3-C5 olefins are desired, a ZSM-5 zeolite catalyst may be used in combination to the one or more AEI zeolites. For example, the CHA type material could be an SSZ-13 or SAPO-34 material while the AEI type can be an SSZ-39 or SAPO-18 material. Some other examples of suitable zeolites to be used in combination with AEI zeolite include X-type, such as 10-X, or Y-type zeolite, although other zeolites with differing pore sizes and acidities, may be used.

A non-limiting list of examples of suitable zeolites for the production of olefins that can be used in combination with the zeolites from the AEI family includes one or more zeolites selected from the group of MOR, EUO, TON, MTT, CHA, MEL, MFI, BEA and FAU families; with preference, the one or more zeolites are selected from the group of EUO, TON, MTT, CHA and MFI families; with most preference, the one or more zeolites are selected from the group of CHA and MFI families. More preferably, the second catalyst composition comprises a mixture of zeolites from the AEI and CHA families.

Suitable AEI zeolites are SSZ-39 or SAPO-18. Non-limiting examples of suitable other zeolites that can be used in combination with AEI zeolites include one or more zeolites selected from the group of ALPO-18, EU-1, ZSM-22, ZSM-23, SAPO-34 and ZSM-5; with preference the one or more zeolites is ALPO-18, SAPO-34, ZSM-5. The one or more zeolites can either be deprived of any aluminium or it can contain aluminium with a Si/AI molar ratio of at least 5.

The crystalline alumino-silicate oxide framework of the one or more zeolite, including AEI zeolites, has a portion of the aluminium that is substituted with boron. Preferentially, boron is used to substitute one or more aluminium atoms in the zeolite framework. Boron-substituted zeolite has a very weak acidity. The zeolite catalysts have a Si/(AI+B) molar ratio of at least 80, typically comprised between 100 and 1200, preferentially of 1000.

Advantageously, when the one or more zeolite is SAPO-34, it can be prepared according to WO 2017/065944, WO 2017/034842, WO 2016/099775 WO 2016/022340 and/or WO 2016/004031.

For example, the second catalyst composition comprises one or more zeolites selected from zeolites having pores sizes ranging from an 8-membered ring channel to a 10-membered ring channel. Suitable zeolites can be found in the “Atlas of Zeolite Framework Types".

For the second catalyst composition comprises one or more AEI zeolites and one or more zeolites selected from the group of CHA and MFI families. Preferably, the second catalyst composition comprises one or more CHA zeolites selected from SSZ-13 and/or SAPO-34; and/or that the second catalyst composition comprises one or more MFI zeolites selected from ZSM-5 and/or silicallite-1; and/or the one or more AEI zeolites of the are selected from SSZ- 39 and/or SAPO-18.

For example, the second catalyst composition comprises one or more CHA zeolites and the second reaction conditions comprise a temperature ranging from 350°C to 450°C.

For example, the second catalyst composition comprises one or more MFI zeolites and the second reaction conditions comprise a temperature ranging from 280°C up to 350°C.

For example, the second catalyst composition is or comprises one or more AEI zeolites with a Si/AI molar ratio ranging from 5 to 200; with preference, the second catalyst composition is or comprises SSZ39. For example, the second catalyst composition is different from the first catalyst composition; and the first catalyst composition comprises titanium phosphate, cobalt phosphate, vanadium phosphate, copper phosphate, manganese phosphate, nickel phosphate, chromium phosphate, iron phosphate, CeC>2, (VO) ₂ P ₂ C> ₇ , T1O ₂ , EuOCI, ZrC>2, SnC>2, AI2O3, S1O2, CuCh, RUO2, UO3, UO2, UO, U3O5, U2O5, U3O7, U3O8, U4O9, uranium oxychlorides, sulphated oxides, ruthenium oxychlorides, TiC, WC, BC, BN, SiN, or any mixtures thereof; for example, the first catalyst composition comprises CeC>2, ZrC>2, UO ₂ , or T1O ₂ or any mixtures thereof.; and the second catalyst composition is or comprises one or more AEI zeolites and optional one or more other zeolites selected from zeolites having pores sizes ranging from an 8-membered ring channel to a 10-membered ring channel.

With preference, the second catalyst composition is one or more AEI zeolites or a mixture of one or more AEI zeolites and one or more zeolites selected from the group of CHA, EUO, MFI, MTT and TON families.

It is preferred that the one or more zeolites, including the one or more AEI zeolites, in the second catalyst composition are subjected to a step of steaming before step (e). The steam treatment is conducted at elevated temperature, preferably in the range of from 400 to 1000°C, more preferably in the range of from 500 to 900°C and at a partial pressure of steam from 0.01 to 20 kPa, preferentially from 0.5 to 1.5 kPa. The concentration of steam in the flow is between 1 to 100%, more preferably from 5 to 20% of steam. The diluent is a gas selected from the group of N2, air, natural gas, CO2 or a mixture of thereof. The steam treatment is preferably carried out for a period of from 0.1 to 200 hours, more preferably from 0.2 hours to 24 hours. The steam treatment tends to reduce the amount of tetrahedral aluminium in the crystalline silicate framework, by forming alumina. The particular effect consists of reducing the strong Bronsted external acidity of the zeolites.

In another embodiment said zeolitic materials that include a microporous crystalline framework, including the one or more AEI zeolites, can be substituted with one or more Lewis acid sites. In some embodiments, the first Lewis acid metal center and the second Lewis acid site can be independently chosen from Sn, Hf, Zn, Zr, Ti, V, Ta, Ga, Ge, Nb, Mo, Co, W, and Cr. In some embodiments, the first Lewis acid metal center and the second Lewis acid site can be independently chosen from Sn, Hf, Zr, and Ge.

For example, the second catalyst composition is or comprises one or more AEI zeolites; wherein AEI zeolites are one or more metal-containing AEI zeolites selected from molybdenum-containing AEI zeolites, tin-containing AEI zeolites, vanadium-containing AEI zeolites, tungsten-containing AEI zeolites and iron- containing AEI zeolites. With preference, the one or more metal-containing AEI zeolites are one or more selected from metal-containing SSZ-39 and metal-containing SAPO-18.

For example, the second catalyst composition comprises one or more CHA zeolites; wherein CHA zeolites are one or more metal-containing CHA zeolites selected from molybdenum- containing CHA zeolites, tin-containing CHA zeolites, vanadium-containing CHA zeolites, tungsten-containing CHA zeolites and iron- containing CHA zeolites. Wth preference, the one or more metal-containing CHA zeolites are one or more selected from metal-containing SSZ- 13 and metal-containing SAPO-34.

For example, the second catalyst composition comprises one or more MFI zeolites; wherein MFI zeolites are one or more metal-containing MFI zeolites selected from molybdenum- containing MFI zeolites, tin-containing MFI zeolites, vanadium-containing MFI zeolites, tungsten-containing MFI zeolites and iron- containing MFI zeolites. Wth preference, the one or more metal-containing MFI zeolites are one or more selected from metal-containing ZSM-5 and metal-containing silicalite-1.

The quantity (and by extension concentration) of paired Lewis acid sites included within the microporous crystalline framework of the zeolitic material can be varied. For example, in some embodiments, the molar ratio of Lewis acid sites to Si atoms in the zeolitic material can be at least 1 :1000 (e.g., at least 1:500, at least 1 :400, or at least 1 :200). In some embodiments, the molar ratio of Lewis acid sites to Si atoms in the zeolitic material can be from 1:1000 to 1:50 (e.g., from 1:400 to 1 :50).

All the above-mentioned catalyst can preferably be treated with an acidic solution such as a sulphuric acid solution. For example, the acidic solution has a concentration ranging from 0.1 M to 18.4 M, preferably the concentration is ranging from 1 M to 6 M.

Operatinq conditions of step (c) forforminq methyl chloride intermediate

In a preferred embodiment, the reaction conditions of step c) include a temperature ranging from 200°C to 700°C, preferably from 300°C to 600°C. In a more preferred embodiment, the temperature ranges from 350°C to 550°C.

Advantageously, a weight hourly space velocity (WHSV) of the first stream is higher than 0.5 h ¹ is used, preferably between 0.5 to 50 h ¹ , more preferably between 0.5 and 5 h ¹ , even more preferably between 1.0 to 3 h ¹ , or is about 1 h ¹ , 1.5 h ¹ , 2 h ¹ , 2.5 h ¹ , 3 h ¹ . The first stream is containing CH ₄ , HCI and O ₂ in the defined proportions. The presence of other components, which could originate from impurities of methane source stream or recycle stream, e.g. higher hydrocarbons, which might be paraffins or olefins, carbon monoxide and small amounts of carbon dioxide, is not disturbing for the formation of methyl chloride step.

With preference, the pressure can be less than 3 MPa, preferably less than 2 MPa, more preferably less than 1.8 MPa, even more preferably less than 1 MPa.

This reaction occurs with a significantly high degree of selectivity to methyl chloride and preferably full conversion of oxygen present in the stream into water. The effluent could contain some other alkyl chlorides, hydrogen chloride, hydrochloric acid, water, traces of unreacted oxygen, carbon monoxide and carbon dioxide, and is substantially free of oxygen.

The composition of the first stream 3

The molar concentration in the first stream of ChU can be at least 20 mol % based on the total molar content of the first stream, preferably 50 mol %.

The molar concentration in the first stream of HCI can be at least 15 mol % based on the total molar content of the first stream, preferably 20 mol %.

The molar concentration in the first stream of O2 can be at least 5 mol % based on the total molar content of the first stream, preferably 10 mol %.

The molar concentration in the first stream of CO2 can be less than 0.5 mol % based on the total molar content of the first stream, preferably less than 0.1 mol %, most preferably the first stream is substantially free of CO2.

Wth preference, the first stream should be substantially free of water as the presence of humidity has a negative effect on the conversion of HCI and methane in the first catalyst bed. The methane source in the first stream could be purified methane from a natural gas reservoir substantially free H2S and other sulphur-containing compounds, e.g. mercaptans, and sulphides. The removal of the latter could be performed by any suitable techniques, e.g. by an amine treatment or any other method. Optionally, it could contain up to 60 molar % of higher hydrocarbons, e.g. ethane, propane or butane. It is of particular advantage as the presence of higher saturated hydrocarbons will improve the yield of olefins. It is advantageous if the first stream is formed by mixing the methane source with oxygen and with HCI recovered during the separation of the olefins from the third stream. In this case, oxygen could be brought as a part of the atmospheric air or as a pure stream from an air separation unit. In another embodiment, the methane source in the first stream could be a flare gas which could originate from oil-gas extraction, refineries, chemical plants, coal industry or landfills. Flare gas is known to have a higher hydrocarbon present (see Table 4). The presence of C2-C6 paraffins may be advantageous for the process as the latter will increase the total yield of olefins. Table 4. Example of possible flare gas compositions.

The methane source of the first stream can also originate from a pre-treated natural gas coming from a natural gas reservoir. Operating conditions of step (e) for forming olefins

With regards to the operation conditions of step (e), the temperature may range from 200°C to 600°C, preferably from 230°C to 550°C. In a more preferred embodiment, the temperature ranges from 250°C to 450°C. A weight hourly space velocity (WHSV) of alkyl halide higher than 0.5h ¹ can be used, preferably between 0.5 to 50 h 1, or between 0.5 to 10 h ¹ , more preferably between 0.5 and 5 h ¹ , even more preferably between 0.5 to 3 h ¹ , or between 1.0 to 3 h ¹ , or is about 0.5 h ¹ , 1 h ¹ , 1.5 h ¹ , 2 h ¹ , 2.5 h ¹ , 3 h ¹ . The pressure can be less than 1.4 MPa preferably less than 0.7 MPa, even more preferably less than 0.5 MPa.

At temperatures exceeding 600°C, it is believed that a high conversion to methane and carbonaceous coke may occur due to pyrolysis of methyl chloride. In the preferred operating temperature range of between 200°C and 450°C, a lesser amount of coke may build up on the catalyst over time during operation. Coke build-up may be problematic as it can lead to a decline in catalyst activity over a range of hours, up to hundreds of hours, depending on the reaction conditions and the composition of the feed gas. It is believed that higher reaction temperatures above 400°C are leading to the formation of carbon or coke. Consequently, higher reaction temperatures allow to reach higher conversion of methyl chloride but lower carbon efficiency and increase the rate of catalyst deactivation. However, the latter could be tolerated if the second catalyst bed is a moving-bed, fluidized bed, or fluidized bed with a riser.

It is of importance that operating temperature together with the catalyst type plays an important role in the distribution of products in the effluent. For example, when a SAPO type zeolite catalyst (e.g. SAPO-34) is used, it may be advisable to operate at a temperature within the range of about 350°C to 450°C; this will lead to the formation of C2-C3 olefins as the major product and a small amount of higher hydrocarbons. Alternatively, in an embodiment involving a ZSM-5 zeolite catalyst operating in a slightly lower temperature range of about 280°C to 350°C primarily C3-C5 olefins will be formed with small amounts of by-products, e.g. aromatic compounds and heavier hydrocarbon fractions. For MFI-type zeolites, product distribution could be further modified by varying SAR (Silica to Alumina Ratio, S1O2/AI2O3) and operating temperature. Yet in an embodiment involving non-zeolitic catalysts, e.g. EuOCI, CeC> ₂ , or ZrC> ₂ , a higher temperature range, i.e. 450°C to 550°C is preferred, and major product in the effluent will be C2-C4 olefins.

The presence of small amounts of oxygen in the feed stream, for instance, below 1 vol.%, is not disturbing for olefin formation but could have a negative effect on selectivity to olefins. Therefore, it is desired that the feedstream used for step (e) olefin formation is substantially free of oxygen. Alternatively, said oxygen could react with carbon monoxide which might be present in the stream coming from said step (c) to produce CO2.

The presence of carbon monoxide and carbon dioxide are not disturbing for the reaction of olefin formation and these compounds will pass unchanged through the catalyst bed under the reaction conditions. The presence of higher alkyl chlorides in the feedstream used for step (e) of olefin formation is not disturbing for the olefin formation as said higher alkyl chlorides will undergo the reaction of dehydrochlorination with the production of higher hydrocarbons under the reaction conditions used in step (e):

CnH _2n+i CI ®· CnH _2n + HCI

Advantageously, dichlorides and trichlorides, which could be present in the feedstream used for the step (e) of olefin formation, would be converted into higher hydrocarbons, e.g. aromatics, hydrogen chloride and coke at the reaction temperatures used in step (e). Therefore, the presence of said higher alkyl chlorides, dichlorides and trichlorides is not having a considerable effect on the reaction of olefin formation. Said coke could further be removed during the catalyst regeneration cycle in the form of carbon dioxide.

In another embodiment said dichlorides and trichlorides could be selectively hydrogenated into methyl chloride by adding hydrogen to the feed stream and applying a suitable catalyst.

In yet another embodiment said dichlorides and trichlorides could be separated from the feed stream used for the step (e) and be used as chemicals, carburized to recover hydrogen chloride and carbon black, or oxidized to produce carbon dioxide and hydrogen chloride.

Recycling unreacted chloromethane

With regards to the recycling of unreacted CH ₃ CI, the unreacted CH ₃ CI if any is removed from the third gaseous stream, optionally by distillation. It is advantageous if gaseous effluent is first compressed and then compressed gases may be treated with the aromatic contacting solvent in the distillation column. However, it is desirable to first remove the lighter components from the third stream, i.e. , methane, ethane, ethylene; these hydrocarbons may be removed according to techniques known in the art. The aromatic contacting liquid is contacted with the CHsCI-containing hydrocarbon in a distillation column. For example, the CHsCI-containing hydrocarbon stream may be continuously fed to a distillation column below the point of entry of the aromatic contacting liquid. The aromatic contacting liquid then flows downwardly in the column and thus contacts the rising stream of CHsCI-containing hydrocarbon. The aromatic contacting liquid containing the methyl chloride is then taken off as bottoms and the purified hydrocarbon is taken off overhead. Any aromatic contacting liquid which comes off overhead may be separated from the hydrocarbon such as by distillation in a second column to flash off the hydrocarbon overhead. Preferably the aromatic contacting liquid will not be added at the very top of the distillation column, but rather there will be some plates or packing above the inlet point for the aromatic contacting liquid so that most or all of the aromatic contacting liquid is fractionated from the overhead vapours. Conventional distillation columns such as packed columns, bubble cap columns and other types known in the art may be utilized.

The operating details of the process such as temperatures at the top and bottom of the column pressures, rate of feed of contaminated hydrocarbon and aromatic contacting liquid, ratios of ingredients taken off overhead and as bottoms, and so forth, will be dependent upon the process variables including the particular compositions being separated and the aromatic contacting liquid selected. These particular variables are subject to some choice. Generally, the temperature at the top of the column will be within the range of about 5 to 100°C and the temperature at the bottom of the column will be in the range of about 50 to 250°C. With the preferred solvents and operating conditions, the temperature at the top of the column will ordinarily be within the range of 10°C to 50°C and the temperature at the bottom of the column within the range of about 100°C to 200°C. Pressures within the column may be atmospheric, sub-atmospheric or super-atmospheric.

It is an advantage that the separation of the methyl chloride from the hydrocarbon can be made efficiently with a relatively small amount of aromatic contacting liquid. Separation of methyl chloride may be obtained with about 99 mol.% aromatic contacting solvent based on the total composition in the distillation column. However, it is an advantage that the separation may be made with relatively small amounts of aromatic contacting solvent such as from about 5 to 35 mol.% aromatic contacting solvent based upon the total composition in the distillation column.

Suitable aromatic contacting liquids are such as benzene, toluene, o-xylene, m-xylene, p- xylene, chlorobenzene, m-dichlorobenzene, aniline, and o-chlorotoluene. Mixtures of the described aromatic contacting liquids with each other may be employed. Furthermore, mixtures with water may be effectively utilized. Particularly desirable results may be obtained by such combinations of water and aromatic contacting liquid. If water is added, conveniently the water will be present in an amount between about 0.5 wt% based on the total, but ordinarily, the water will be present in an amount between 0.5 wt% and 10 wt%. The treated hydrocarbon comes from the overhead from the solvent contacting column.

The purified hydrocarbon product may be further purified by any of the methods known in the art for separating these hydrocarbon mixtures.

Recycling of HCI

Wth regards to the recovery of HCI, it could be performed through extraction followed by distillation. The method of extractive distillation involves the addition of an extractive agent 43 with hygroscopic properties to shift or remove the azeotropic point and increase the volatility of HCI. Advantageously, sulfuric acid (H ₂ SO ₄ ) and calcium chloride (CaCh) are used as the extractive agents 43 due to the high chemical stability of these compounds to the environment of HCI and hydrochloric acid. A non-bounding example of the extractive distillation system 35 is shown in Figure 4. The concentrated extractive agent 43 could be directed into an extractive column 41 to trap water. The diluted extractive agent 45 could further be recovered from the bottom of the extractive column 41 before being re-concentrated into the concentrator 49, through optionally being passed via re-boiler 47. A water stream 59 can be evacuated from the concentrated 49, optionally through the condenser 57. Highly concentrated HCI gas 51 could be collected at the top of the extractive column 41 and passed through one or more condensers 53 for additional purification, before being advantageously conveyed through a knock-out drum 55 (i.e. a vapor-liquid separator), to produce a stream 37 of dry HCI. Those skilled in the art could apply required modifications to the HCI purification scheme depending on the required process scale and efficiency.

In another embodiment of HCI extraction, thermal desorption could be used. This method is the most advantageous for the concentrated hydrochloric acid solution containing more than about 20 % hydrogen chloride. The procedure for obtaining a high purity anhydrous hydrogen chloride then involves the desorption of HCI from a concentrated hydrochloric acid solution containing more than about 20 % hydrogen chloride, hydrogen chloride gas is driven out until the concentration of the solution approaches 20 % HCI, which is the concentration of the azeotrope. The lean hydrochloric acid is then returned to an absorption system to be enriched with hydrogen chloride, thus completing the cycle. Recovered HCI gas could be further purified by passing through at least one condenser.

In yet another embodiment, a non-aqueous absorbing medium could be utilized. In these systems, the impurities are absorbed preferentially in the organic solvent, leaving a purified HCI gas.

Once HCI gas has been recovered, further treatment can be advantageously carried out to further purify the HCI gas. HCI gas containing condensable and/or liquefiable impurities, such as water and reactive organic and inorganic compounds, can thus be treated to remove substantially all of the water from the HCI gas and at least that portion of the organic and inorganic compounds which will solidify upon the subsequent compression of the HCI gas to a liquefaction pressure. The thus-treated gas is then compressed to a suitable liquefaction pressure, desirably at least about three atmospheres and is introduced into a fractionation zone, wherein it is counter-currently contacted with liquid hydrogen chloride while reflux conditions are maintained within the fractionation zone. A liquid fraction containing impurities having a higher boiling point than HCI is removed substantially continuously from the lower portion of the fractionation zone and a purified hydrogen chloride product, substantially free of higher boiling impurities, is recovered from the upper portion of the zone. The purified HCI product may be recovered either as a gas or it may be liquefied or condensed. The liquefaction of the hydrogen chloride product may be desirable to provide further purification of the hydrogen chloride gas, for example where appreciable quantities of non-condensable impurities and/ or impurities having a boiling point below that of hydrogen chloride are present.

Exemplary of the contaminants, but by no means all-inclusive thereof, which may be separated from HCI gas by the process of the present disclosure are water; chlorine; halogenated lower compounds such as carbon tetrachloride, chloromethanes, ethyl chlorides, aromatics, such as hexachlorobenzene; inorganics, such as metal chlorides.

Accordingly, it is important that before compression to the liquefaction pressure, the HCI gas is treated to reduce the water content thereof to a maximum concentration of about 100 ppm and preferably less than 50 ppm. Many suitable methods for effecting this desired water removal from this hydrogen chloride gas will be apparent to those in the art. For example, the hydrogen chloride gas may be brought into contact with a solid adsorbent, such as silica gel, alumina gel, a molecular sieve, and the like, to effect water removal. As such adsorbents become saturated with the water removed from the HCI gas, they may be reactivated by heating, and thereby may be reused for many cycles. In another method, the hydrogen chloride gas is contacted with a chemical reactant which will combine with the water. Typical reactants are those which form a hydrate, such as sulfuric acid, calcium chloride, and the like. Where reactants are used which form a hydrate, these may be reactivated by heating, similarly to the solid adsorbent.

As a further alternative, water in the hydrogen chloride may be removed by cooling the gas to form a condensed aqueous phase which is then separated from the gaseous HCI. Various methods for effecting the desired cooling of the gas may be used, including many direct and indirect contact heat exchange techniques. Since the temperature to which the hydrogen chloride is cooled will depend, in part at least, upon the pressure at which the gas is handled, it may be desirable to carry out the cooling of the gas under pressure, e.g., from about 1 to about 4 atmospheres. This not only makes it possible to condense the water impurities in the HCI at a higher temperature, thus reducing the amount of refrigeration equipment required, but also provides an initial compression stage for the hydrogen chloride which is ultimately to be compressed to the liquefaction pressure. The condensed water in the HCI gas may then be removed by various methods, for example, by electrostatic precipitation, with passing the gas through a demister, or the like. As has been indicated hereinabove, organic and inorganic impurities, other than water, may also be removed from the hydrogen chloride in this pretreatment operation. Generally, it is desirable to remove substantially all of the organic or inorganic impurities which may form solids in the subsequent compressor system and which may also have a detrimental effect on the subsequent purification operations. Removal of the organic substituents may be accomplished by cooling the HCI gas to condense the impurities and thereafter, separating the condensed material from the gas. In some instances, it has been found desirable in removing these organic and inorganic materials to scrub the hydrogen chloride gas with a high boiling scrubbing liquid, such as the high boiling organic compounds. In these instances, it has been found that the beneficial effects of cooling and scrubbing may be realized by utilizing a chilled or cooled scrubbing liquid.

The preferred method of removing both organic and inorganic impurities, including water, in the gas pretreating step, is by the cooling of the gas to condense the impurities with subsequent removal of these condensed impurities, preferably by passing the gas through a demister.

In carrying out the preferred pretreatment operation of the present disclosure, the raw HCI gas, contain minor amounts of organic impurities such as carbon tetrachloride, trichloroethylene, perchloroethylene, hexachlorobutadiene, hexachlorocyclopentadiene, octachlorocyclopentene, hexachlorobenzene, hexachloroethane, pentachloroethane, inorganic substances, such as chlorine, aluminium and magnesium silicates, metallic halides, such as the metallic chlorides, and the like, is introduced into a compressor wherein it is compressed to a pressure within the range of about 0.1 to about 0.4 MPa. Preferably, the gas is compressed to a pressure within the range of about 0.2 to about 0.3 MPa. For this compression, many different types of compressors are suitable. For example, excellent results have been obtained when using a compressor of the Nash turbine type, i.e. a liquid-ring pump. When using such a compressor, however, the sealing liquid used shouldn't be one that will add contaminants to the HCI gas being compressed. Although many different sealing liquids may be used, concentrated sulfuric acid is particularly suitable in that not only does it not add contaminants to the HCI gas but, additionally, it acts as a drying agent to aid in the removal of any water vapour which is present in the gas. It will, of course, be appreciated that other sealing liquids may be used in the Nash turbine type compressor or that compressors other than the Nash turbine type may be used.

The compressed HCI gas is then cooled sufficiently to effect condensation of a major amount of the impurities in the HCI gas, other than chlorine. Generally, the gas is cooled to a temperature within the range of about to about -10°C. It is believed that some of this plugging may be attributed to the formation of a solid hydrogen chloride hydrate which forms at temperatures below about 15°C. Accordingly, it is preferred that the HCI gas is cooled to a temperature within the range of about 0 to about 10 °C.

This cooling may be done using various methods. For example, indirect heat exchange methods may be used wherein the gas is passed in contact with a cooled surface, such as cooling coils through which a cooling media is circulated. Alternatively, the compressed raw hydrogen chloride gas may be cooled by direct contact refrigeration cooling, for example, by passing it through a packed tower in countercurrent contact with a liquid cooling media. Many different types of cooling media may be utilized, provided they do not contaminate the hydrogen chloride gas with which they are in contact. For example, high boiling organic materials, such as those which are condensed from the hydrogen chloride gas stream being treated, may be cooled by any convenient means, for example, by passing them in Contact with a refrigeration coil, and thereafter brought into countercurrent contact with the HCI gas stream to be purified to effect cooling thereof and condensation of the impurities in the gas stream. In this manner, or by using other equivalent cooling techniques, substantially all of the water and high boiling organic impurities, as well as a large portion of the lower boiling organic impurities and the inorganic impurities, are condensed or solidified in the gas stream in the form of a mist.

Once the impurity mist has been formed in the hydrogen chloride gas, it is subjected to further treatment to effect removal of the impurity mist from the gas. Here again, many different methods are suitable for effecting the removal of the mist from the gas. For example, the hydrogen chloride gas containing the impurity mist may be passed through electrostatic precipitators; mechanical type de-misters, such as cyclones, impingement type de-misters, such as those utilizing mats or pads of various fibrous materials such as glass fibres, ceramic fibres, aluminium silicate fibres, metallic fibres, plastic fibres, and the like. For simplicity of operation, it has been found that the impurity mist in the HCI gas stream is preferably removed using an impingement type de-misting device, such as one using a filter pad of aluminium silicate fibres. By operating in this manner, the water content of the HCI gas being treated is reduced to below about parts per million, and generally below about 50 ppm on a volume basis. Additionally, substantial amounts of the high boiling organic impurities, such as the chlorinated butadienes, cyclopentadienes, cyclopentenes, benzenes, and the like, are also removed. Although appreciable quantities of some low boiling organic materials, such as trichloroethylene, perchloroethylene, carbon tetrachloride, chloroform, and the like, may also be removed, as will be pointed out in more detail hereinafter, at least some of these organic materials should remain in the gas, as their presence has been found to give beneficial effects during the subsequent gas treatment. Accordingly, the HCI gas obtained from the partial compression, cooling and demisting operation should contain such lower boiling organic materials in amounts at least about twenty times the volume of any water remaining in the gas, e.g., about 0.1 wt.% of the HCI gas. Appreciably higher amounts of these low boiling organic materials may be present in the composition, for example, amounts as high as about 5 wt.% of the HCI gas. In view of the desirable effects obtained when such quantities of these low boiling organic substituents are present in the HCI gas during the subsequent treatments, where the gas does not contain these organic materials in at least the minimum amount of about 0.1 wt.%, it may be desirable to add such materials to the gas before subsequent purification treatments.

Once the pre-treatment operation has been completed, the gas is compressed to a suitable liquefaction pressure, preferably within the range of about 3 to about 30 atmospheres and the temperature of the hydrogen chloride gas not exceed about 150 °C.

About the compression method and apparatuses used, it will be appreciated that these may be of various suitable types. For example, the compressor may be a reciprocating, centrifugal, radial compressor or the like, the particular design used depending on the scale of operation, the pressure desired and other related factors.

In this fractional distillation step, the hydrogen chloride gas under pressure is introduced into the fractionating column and is counter-currently contacted with liquid hydrogen chloride. The amount of such liquid hydrogen chloride with which the hydrogen chloride gas in the fractionating column is contacted will be at least that amount that is sufficient to provide for 4reiiuxing in the distillation column. Most conveniently, the liquid HCI for such refluxing may be obtained by condensing at least a part of the purified product HCI obtained from the process and returning the thus-condensed portion to the fractionation zone. Alternatively, of course, liquid HCI from many other sources may be used.

As the hydrogen chloride gas is introduced into the fractionation column and reflux conditions are maintained in the fractionation zone of the column, there is obtained in the lower portion of the fractionation zone or column a liquid portion which contains substantially all of the impurities in the hydrogen chloride gas. Generally, it is desirable to provide the distillation or fractionating tower with a heating means or reboiler into which the liquid portion or bottoms from the fractionating column are substantially continuously introduced. Within the heater or reboiler, this liquid portion is at least partially vaporized and the vapour reintroduced into the fractionation or distillation column and passed in the same manner as the hydrogen chloride gas which is introduced into the column. In this way, a more complete separation of the hydrogen chloride gas and the impurities contained therein is obtained and there is found to be very little loss of the hydrogen chloride from the system, with a consequent realization of higher operating efficiencies.

From the reboiler portion of the fractionation equipment, the liquid mixture of chlorine and organic materials may, if desired, be discarded. Alternatively, the chlorine may be stripped from the organic compounds in the mixture in a second or auxiliary column or evaporator. Generally, where this is done, the organic portion obtained may be discarded. If desired, the chlorine stripped from the organic materials may be reintroduced into the chlorine feed stream for the organic chlorination reaction from which the by-product impure hydrogen chloride is obtained.

As mentioned earlier, the purified hydrogen chloride product gas obtained from the top of the fractionation zone may be at least partially condensed to provide the liquid hydrogen chloride required for the reflux in the fractionating column. Although in some instances, all of the purified gaseous hydrogen chlorides may be condensed for example, where a liquid product is desired, or separation of non-condensable products is desired, the amount of gaseous HCI which is condensed is generally only that which is required for reflux, the remainder being taken off as the gaseous product. The weight ratio of the reflux to the gaseous product may be within the range of about 0.1 :1 to about 5:1, although often ratios used may be outside these ranges, depending upon the specific operating conditions encountered.

Optional step of olefin upgrading

Olefin upgrading can be advantageously achieved in a third reaction zone 19 (as shown in figure 2) or in a fourth reaction zone 23 (as shown in figure 3) or in both a third reaction zone and a fourth reaction zone (not shown).

A first suitable optional step of olefin upgrading could be the olefin cracking step. Said olefin cracking step requires utilization of a third catalytical composition which comprises at least one cracking catalyst which can be selected from one or more zeolites and/or one or more clays.

With preference, said cracking catalyst comprises one or more zeolites selected from silicalites from the MFI family, crystalline silicate from the MFI family with a Si/AI atomic ratio of at least 180, crystalline silicate from the MEL family with a Si/AI atomic ratio ranging between 150 and 800, and/or phosphorous-modified zeolite from the MFI, MEL, FER, MOR family and/or phosphorous-modified clinoptilolite. In one embodiment, said cracking catalyst comprises one or more zeolites selected from silicalites from the MFI family, optionally with a silica binder.

Examples of suitable catalysts were disclosed in the international patent application published W02004/048299.

Examples of crystalline silicate from the MFI family are ZSM-5 and silicalite. An example of crystalline silicate from the MEL family is ZSM-11, which is known in the art. Other suitable non-limiting examples are boralite D and silicalite-2, or any mixtures thereof.

The preferred crystalline silicates have pores or channels defined by ten oxygen rings and a high Si/AI atomic ratio. The catalyst having a high Si/AI atomic ratio may be manufactured by removing aluminium from a commercially available catalyst. The commercially available catalysts may be modified by steaming to remove at least part of inter-framework aluminium followed by a leaching step to remove external aluminium.

The cracking catalyst can be formulated with a binder, preferably an inorganic binder, and shaped to the desired shape, e.g. extruded pellets. The binder is an inorganic material selected from clays, silica, metal oxides. Preferably, the binder content ranges from 5 to 50% by weight, more typically from 15 to 35% by weight, based on the weight of the cracking catalyst. More preferably, the binder is a silica binder.

The olefin cracking reaction is known perse. It has been described in EP1035915, EP1036133, EP1036134, EP1036135, EP1036136, EP1036137, EP1036138, EP1036139, EP1190015, EP1194500, EP1194502, and EP1363983. The content of which is incorporated in the present description.

A second suitable optional step of olefin upgrading could be a metathesis process. Said metathesis process requires the utilization of a fourth catalytical composition that comprises at least one metathesis catalyst. The suitable metathesis catalyst could comprise one or more oxides of group VIA metal and/or VIIA metal, preferably molybdenum oxides, tungsten oxides, and/or rhenium oxides. With preference, said one or more oxides of group VIA metal and/or VIIA metal are present in an amount ranging between 0.1 and 50 wt.% of the second catalyst composition, more preferably between 0.5 and 30 wt.%, even more preferably between 1 and 20 wt.%. Suitable molybdenum oxide catalysts are disclosed in WO2011/113836, US3658927 and US4568788. Said catalyst might be prepared by using at least one of molybdenum oxide, possibly combined with one or more cobalt oxides and/or one or more rhenium oxides, and preferentially supported on an inorganic oxide support.

The inorganic oxide support might comprise silica, alumina, silica-alumina, silica-magnesia, silica-titania, alumina-titania, alumina-magnesia, boria-alumina-silica, alumina-zirconia, thoria and/or silica-titania-zirconia.

The molybdenum oxide, possibly in combination with cobalt oxide or with rhenium oxide, can be dispersed on the inorganic support by any conventional method such as impregnation, dry mixing, ion exchange or co-precipitation.

Suitable tungsten oxide catalysts are disclosed in WO2011/113836. The tungsten catalyst is preferably supported on a silica carrier with a tungsten content ranging from 1 to 15 wt.%. The tungsten-based catalyst is heat-treated before used at at least 300°C, preferably at least 500°C. The catalyst can be further activated by treatment with hydrogen, carbon monoxide or ethylene. The tungsten-based catalysts are advantageously used in combination with a co catalyst. Example of suitable co-catalysts are co-catalysts that include compounds chosen among the alkali metals, the alkaline earth metal, the group MB of the periodic table and/or the group IIIA of the periodic table. Among those compounds, lithium, sodium, potassium caesium, magnesium, calcium, strontium, barium, zinc, lanthanum and ytrrium are preferred. These metals are generally used as oxides, as such, or deposited on a carrier, or as mixed oxides. Examples of the latter are hydrotalcites that are double layered hydroxide of aluminium and magnesium, and solid solutions of aluminium oxide and magnesium oxide obtained by calcining the corresponding hydrotalcite. The oxides, mixed oxides, hydroxides, double hydroxides, nitrates and acetates of the metals may be supported on carriers having a large surface area.

Suitable rhenium catalysts are disclosed in WO2011/113836. The rhenium catalyst is preferably supported on an alumina-containing carrier with rhenium content ranging from 0.5 to 20 wt.%, preferably 1 to 15 wt.%. The rhenium catalyst is before use heat-treated at a temperature of at least 400°C, preferably at least 500°C. Optionally the catalyst can be activated before use by treating it with alkyl-boron, alkyl-aluminium or alkyl-tin compounds. The rhenium oxide is deposited on a substrate that comprises a refractory oxide, containing at least alumina and exhibiting an acidic nature, such as, for example, alumina, silica-alumina or zeolites. By way of preferred examples, the catalysts comprise rhenium heptoxide that is deposited on a gamma-alumina, such as those described in US4795734. The catalysts that comprise rhenium heptoxide and that is deposited on alumina can also be modified by the addition of a metal oxide, such as described in FR2709125. 0.01 to 30 wt.% of at least one metal oxide of the niobium or tantalum group can be added.

FR2740056 describes that 0.01 to 10% by weight of aluminium of a compound of formula (RO) _q AIR' _r , where R is a hydrocarbyl radical of 1 to 40 carbon atoms, R' is an alkyl radical of 1 to 20 carbon atoms, and q and r are equal to 1 or 2, with q+r equal to 3, can be added.

The fourth catalyst composition advantageously further comprises an isomerization catalyst, said isomerization catalyst preferably comprising hydrotalcite and/or one or more oxides of alkali metal, alkaline earth metal, group lib and/or group Ilia of the periodic table.

Suitable isomerization catalysts, or co-catalysts, are further disclosed in US4575575, US4684760 and US4754098 and is comprising magnesium oxide which could be deposited on a suitable carrier. The carrier for the co-catalyst is preferably a compound that does not possess acidity, because acid sites may induce oligomerization of olefins. Preferred examples of the carriers for the co-catalysts include carbon, basic zeolites, y-alumina, silica, alkaline earth or alkali silicates, alumino-phosphates, zirconia and titania. The amount of the co-catalyst metal oxide deposited on the carrier is generally in the range of 0.01 to 40 wt.% and is preferably in the range of 0.1 to 20 wt.%. The shapes of the co-catalyst can be essentially any shape such as spherical shapes, cylindrical shapes, extruded shapes and pellets. The shape of the particles should be such that the co-catalyst can be easily mixed with the metathesis catalyst or can be installed above or below the catalyst bed containing the metathesis catalyst. The co-catalyst as of its basic nature exhibits two activities: (i) the isomerisation of alpha-olefins into internal olefins, the latter will result in the disproportionation reaction with ethylene leading to the desired shorter alpha-olefin, namely propylene, (ii) capturing poisons for the metathesis like any compound that has some acidic nature as hydrogen halides.

In the metathesis process, the weight ratio of the co-catalyst to the metathesis catalyst is advantageously from 0.1 to 15, preferably from 1 to 8. It is preferred that the second catalyst composition comprises heterogeneous support, with preference said heterogenous support is alumina, silica and/or zeolites.

Test and determination methods

GC analytics. Gas chromatography experiments were carried out to determine quantitatively the selectivity of the reaction. It was performed with TCD/FID/TIC detectors on a silica BOND column (60 m x 0.32 mm) using Agilent GC operated by Chromeleon software.

Temperature Programmed Desorption (TPD) is the method of observing desorbed molecules from a surface when the surface temperature is increased. It has been performed by following the heating sequences I, II and III showed in Figure 5, respectively corresponding to activation, saturation and analysis. In brief, in the first step, starting from room temperature (25°C) under a flow of helium (rate 50 cc/min), the temperature has been gradually increased to 600°C at a rate of 20°C/min. After 1 hour at 600°C, the zeolite sample is considered as being activated and the temperature is then gradually decreased to 100°C at a rate of 10°C/min. Then, in the second step during 3 hours, the temperature is maintained at 100°C and in the first 1 hour, 10% of ammonia (NH ₃ ) is added to the helium flow (which is decreased to 30 cc/min). The surface of the zeolite is thus saturated with the molecules of ammonia that are going to be adsorbed onto the surface. The last 2 hours of the temperature threshold at 100°C, the initial flow of helium is reinstated. Then, in the third step, the temperature is increased again to 600°C at a rate of 10°C/min to desorb the ammonia. The sample is maintained at 600°C for an additional one hour. It is highlighted that the skilled person could use different parameters (time, temperature, flow rate, carrier gas) to perform the method. The measurement of the amount of ammonia using a thermal conductivity detector allows to recognize of the different adsorption conditions of the ammonia onto the zeolite and allows for obtaining a description of the surface of the zeolite, such as the number of acid sites.

Examples

The embodiments of the present disclosure will be better understood by looking at the different examples below.

Preparation of zeolites suitable for the synthesis reactor Examples 1 to 5

Nine examples of metal-containing MFI zeolite materials are described in the following section (comparative example and examples 1 to 5):

The starting materials used in examples 1 to 5 are as follow:

Tetraehtylorthosilicate (TEOS), 98%, from Aldrich

Tetrapropylammonium hydroxyl (TPAOH), 20 wt.% in water (1 M), from Alfa Aesar Sodium molybdate tetrahydrated (Na ₂ Mo0 ₄ , 4H2O), 98%, from Alfa Aesar Ammonium hepta-molybdate ((NH4) _d Mq7q24), from Alfa Aesar Sodium chloride (NaCI) from Alfa Aesar

Lithium, sodium, potassium, or caesium vanadate (Li, Na, K, CsV03) from Aldrich Sodium stannate (NaaSnCh), 95%, from Aldrich Double distilled water

These materials were used as received from manufacturers without any further purification. The zeolite samples described in the following examples are characterized by various methods as listed below:

Scanning electron microscopy (SEM):

Scanning electron microscopy images of examples after step 8) were recorded using a MIRA\LMH (TESCAN) microscope, with an electron beam of 30 kV.

Powder X-ray diffraction (XRD):

Powder samples of zeolites obtained after step 8) were measured using a PANalytical X’Pert Pro X-ray diffractometer equipped with a monochromator specific to CuKa radiation (l = 1.5418 A, 45 kV, 40 mA). Samples were measured from 3 to 70 ° 2Q, with a step size of 0.016°.

Le Bail profile refinement of each XRD patterns was also performed.

Solid-state nuclear magnetic resonance of silicon ( ²⁹ Si MAS NMR):

Powder samples obtained after step h) are packed into zirconia rotor of 4 mm outer diameter spun at 12 kHz, in a Bruker Avance lll-HD 500 (11.7 T) spectrometer operating at 99.3 MHz. 29Si MAS NMR spectra are recorded from a single pulse excitation (30° flip angle), used with a recycle delay of 30 s. {1 H} 29Si cross-polarization (CP) solid-state MAS NMR was acquired using a contact time of 5 ms and a recycle delay of 2 s. Chemical shifts were referenced to tetramethyl silane (TMS).

Solid-state nuclear magnetic resonance of phosphorus ( ³¹ P MAS NMR):

The powdered sample obtained after step 8) and subsequently ion exchanged to have the H- form, are analysed in ³¹ P MAS NMR under 1 H decoupling, using a phosphorus probe molecule: trimethylphosphine oxide (TMPO). All the following preparation steps are performed under the Argon atmosphere to prevent the interaction of water with the probe molecule. The sample is first dehydrated, by heating at 400°C for 4h under vacuum (av. 4.0 *10-5 Torr). In the meanwhile, a solution of TMPO dissolved in dichloromethane is prepared in anhydrous conditions. The solution is then added to the dehydrated sample. The as-obtained suspension is then subjected to sonication for 15 minutes, before the dichloromethane solvent is removed under vacuum, leaving the TMPO probe molecule impregnated into the zeolite sample. TMPO loaded sample is then packed into 4 m outer-diameter zirconium rotor and analyzed using 31 P MAS NMR, performed on an 11.7 T Bruker Avance 500 spectrometer operating at a frequency of 500.0 MHz and 202.4 MHz for 1 H and 31 P respectively. A spinning rate of 14 kHz was used. 31 P TT/2 and tt-pulses lengths were 7 and 14 ps respectively for all measurements.

Raman spectroscopy:

Samples obtained after step 8) were measured using Raman spectrometry. The Raman spectra were collected on a Jobin Yvon Labram 300 confocal Raman spectrometer coupled to an optical microscope (objective 50x) and a CCD detector. A 532 nm wavelength laser was used, and spectra were accumulated 3 times for 60 s each. The power applied to the sample did not exceed 20 mW upon measurement.

Scanning transmission electron microscopy with energy dispersive X-Ray analysis (STEM/EDS) and High Angle Annular Dark Field imaging (HAADF-STEM):

Experiments were performed on an Analytical double (objective and probe) corrected JEOL ARM200CF equipped with a 100 mm Centurio EDS detector and a Quantum GIF for the EELS. A probe of 0.1 nm was used to scan the sample in STEM mode and Bright Field and High Angle Annular Dark Field detectors were simultaneously employed for imaging. Camera length was 8 cm, and two different accelerating voltages of 200 and 80 kV were used in the STEM mode for imaging and chemical analysis respectively. Owing to the enhanced Z-contrast developed at 200 kV, this configuration was used for imaging and a high-speed scanning protocol (10 psec/px) was employed to prevent sample degradation under the electron beam. To avoid such degradation, STEM-EDS analytical assays were carried out at 80 kV, with a scanning speed of 3 ps/px for a mean duration of 60 minutes. A cross-correlation algorithm implemented in the Jeol Analysis Station software was applied every 30 seconds to compensate for the special drift occurring during the test. The microstructure of samples was checked before and after each EDS scan.

Inductively coupled plasma (ICR) optical emission spectrometry was used to determine the chemical compositions using a Varian ICP-OES 720-ES. The Si/AI molar ratio or the Si/M molar ratio are determined using the said method.

Comparative example - SiMFI zeolite

Preparation of purely siliceous Si-MFI zeolite from the same qel composition and crystallization method as samples of the present invention. Note: this sample is not part of the invention Step 1):

In a polypropylene synthesis bottle (125 ml_), solution A is prepared by adding 24.591 g of TPAOH (1M) and 42.581 g of double-distilled water, under agitation performed using a magnetic stirrer. To this solution A is then added drop-wise 18 g of TEOS, under stirring performed by a magnetic stirrer. The solution should be water clear and liquid. Upon preparation, the gel might be slightly inhomogeneous, but the solution should end up being water-like during the ageing step (beginning of step b)). The final overall molar gel composition (solution A and B mixed) is 1 Si0 ₂ : 0.28 TPAOH: 40 H20.

Step 2):

The bottle containing the solution prepared in step 1) is air-tightly closed with a cap. The as- made synthetic suspensions are left for ageing under magnetic stirring for 1 h, and then on an orbital shaker for an additional 18h. All the steps up to this point are performed at a temperature between 10 and 35 °C and an ambient pressure between 0.09 and 0.12 MPa.

Step 3):

The synthesis mixture is water-like at this point. The synthetic mixture, still in its air-tightly closed bottle, is then subjected to static hydrothermal treatment at 90°C, for a duration of 48h.

Step 4):

The sample is removed from the oven after step 3), and cooled down to room temperature. The solid phase is then separated from the liquid phase using centrifugation. The solid is dispersed in distilled water and centrifugation is performed again. This washing procedure is repeated until the pH of the liquid separated from the solid phase is around 7-8.

Step 5):

The obtained solid sample is then dried in a static oven at 80°C overnight.

The dried sample retrieved is then subjected to the following calcination procedure: In ambient atmospheric conditions (composition of the atmosphere, and atmospheric pressure), the sample is placed in a muffle furnace. The furnace heats up from room temperature to 550°C in 5h, holds at 550°C for an additional 5h, before the furnace is allowed to cool down to room temperature in 5h. The as-obtained sample from step 5) is called SiMFI.

Example 1 - MoMFI-1

Preparation of molybdenum (Mo) containing MFI zeolite by staged synthesis approach (metal source was added to the amorphous material with a delay of 5h)

Step 1):

In a polypropylene synthesis bottle (125 ml_), solution A is prepared by adding 8.197 g of TPAOH (1M) and 11.194 g of double-distilled water, under agitation performed using a magnetic stirrer. To this solution A is then added drop-wise 6 g of TEOS, under stirring performed by a magnetic stirrer. The solution should be water clear and liquid. Upon preparation, the gel might be slightly inhomogeneous, but the solution should end up being water-like during the ageing step (beginning of step 2)).

Step 2):

The bottle containing the solution prepared in step 1) is air-tightly closed with a cap. The as- made synthetic suspensions are left for ageing under magnetic stirring for 1 h, and then on an orbital shaker for an additional 18h. All the steps up to this point are performed at a temperature between 10 and 35 °C and an ambient pressure between 0.09 and 0.12 MPa.

Step 3):

The synthesis mixture is water-like at this point. The synthetic mixture, still in its air-tightly closed bottle, is then subjected to static hydrothermal treatment at 90°C, for a duration of 5h. Step 4):

The synthesis bottle is retrieved from step 3), and cooled down to room temperature under magnetic agitation, without opening the bottle. The synthesis mixture inside is still fully amorphous at this stage of the synthesis method. A solution B is prepared from 0.553 g of sodium molybdate di-hydrated Na2MoC>4, 2H2O dissolved in 3 ml_ of double-distilled water. The solution is hand-shaken until it becomes water-clear. Solution B is then added drop-wise to the mixture that has just been cooled down, under vigorous magnetic stirring.

Step 5):

After full addition of the metal source, the bottle is closed again and left under magnetic stirring for an additional 1 h. The final overall molar gel composition (solution A and B mixed) is 1 S1O2: 0.28 TPAOH: 0.08 Mo0 ₃ : 0.08 M’ ₂ 0: 40 H20.

Step 6):

The obtained synthesis mixture from step 5) is then placed in a static oven at 90°C for 43 h. Step 7):

The sample is removed from the oven after step 5), and cooled down to room temperature. The solid phase is then separated from the liquid phase using centrifugation. The solid is dispersed in distilled water and centrifugation is performed again. This washing procedure is repeated until the pH of the liquid separated from the solid phase is around 7-8.

Step 8):

The obtained solid sample is then dried in a static oven at 80°C overnight.

The dried sample retrieved is then subjected to the following calcination procedure: In ambient atmospheric conditions (composition of the atmosphere, and atmospheric pressure), the sample is placed in a muffle furnace. The furnace heats up from room temperature to 550°C in 5h, holds at 550°C for an additional 5h, before the furnace is allowed to cool down to room temperature in 5h. The as-obtained sample from step 8) is called MoMFI-1. Example 2 - MoMFI-2

Preparation of molybdenum (Mo) containing MFI zeolite by staged synthesis approach (metal source was added to the fully crystalline material with a delay of 48h)

Step 1):

In a polypropylene synthesis bottle (125 ml_), solution A is prepared by adding 8.197 g of TPAOH (1M) and 11.194 g of double-distilled water, under agitation performed using a magnetic stirrer. To this solution A is then added drop-wise 6g of TEOS, under stirring performed by a magnetic stirrer. The solution should be water clear and liquid. Upon preparation, the gel might be slightly inhomogeneous, but the solution should end up being water-like during the ageing step (beginning of step 2)).

Step 2):

The bottle containing the solution prepared in step 1) is air-tightly closed with a cap. The as- made synthetic gel is left for ageing under magnetic stirring for 1 h, and then on an orbital shaker for an additional 18h. All the steps up to this point are performed at a temperature between 10 and 35 °C and an ambient pressure between 0.09 and 0.12 MPa.

Step 3):

The synthesis mixture is water-like at this point. The synthetic gel, still in its air-tightly closed bottle, is then subjected to static hydrothermal treatment at 90°C, for a duration of 48h.

Step 4):

The synthesis bottle is retrieved from step 3), and cooled down to room temperature under magnetic agitation, without opening the bottle. The mixture inside is composed of purely siliceous fully crystalline MFI zeolite in its mother-liquor. A solution B is prepared from 0.553 g of sodium molybdate Na2MoC>4, 2H2O dissolved in 3 ml_ of double-distilled water. The solution is hand-shaken until it becomes water-clear. Solution B is then added drop-wise to the mixture that has just been cooled down, under vigorous magnetic stirring.

Step 5):

After full addition of the metal, the synthesis bottle is closed again and left under magnetic stirring for an additional 1 h. The final overall molar gel composition (solution A and B mixed) is 1 Si0 ₂ : 0.28 TPAOH: 0.08 Mo0 ₃ : 0.08 M’ ₂ 0: 40 H ₂ 0.

Step 6):

The obtained synthesis mixture from step 5) is then placed in a static oven at 90°C for 24 h. Step 7):

The sample is removed from the oven after step 5), and cooled down to room temperature. The solid phase is then separated from the liquid phase using centrifugation. The solid is dispersed in distilled water and centrifugation is performed again. This washing procedure is repeated until the pH of the liquid separated from the solid phase is around 7-8. Step 8):

The obtained solid sample is then dried in a static oven at 80°C overnight.

The dried sample retrieved is then subjected to the following calcination procedure: In ambient atmospheric conditions (composition of the atmosphere, and atmospheric pressure), the sample is placed in a muffle furnace. The furnace heats up from room temperature to 550°C in 5h, holds the temperature at 550°C for an additional 5h before the furnace is allowed to cool down to room temperature in 5h. The as-obtained sample from step 8) is called MoMFI-2.

Example 3 - SnMFI

Preparation of tin ( Sn ) containing MFI zeolite by staged synthesis approach (metal source was added to the amorphous material with a delay of 5h)

Step 1):

In a polypropylene synthesis bottle (125 ml_), solution A is prepared by adding 8.197 g of TPAOH (1M) and 11.194 g of double-distilled water, under agitation performed using a magnetic stirrer. To this solution A is then added drop-wise 6g of TEOS, under stirring performed by a magnetic stirrer. The solution should be water clear and liquid. Upon preparation, the gel might be slightly inhomogeneous, but the solution should end up being water-like during the ageing step (beginning of step 2)).

Step 2):

The bottle containing the solution prepared in step 1) is air-tightly closed with a cap. The as- made synthetic gel is left for ageing under magnetic stirring for 1 h, and then on an orbital shaker for an additional 18h. All the steps up to this point are performed at room temperature and ambient pressure.

Step 3):

The synthesis mixture is water-like at this point. The synthetic gel, still in its air-tightly closed bottle, is then subjected to static hydrothermal treatment at 90°C, for a duration of 5h.

Step 4):

The synthesis bottle is retrieved from step 3), and cooled down to room temperature under magnetic agitation, without opening the bottle. The synthesis mixture inside is still fully amorphous at this stage of the synthesis method. A solution B is prepared from 0.461 g of sodium stannate tri-hydrated Na2SnC>3, 3H2O dissolved in 3 ml_ of double-distilled water. The solution is hand-shaken until it becomes water-clear. Solution B is then added dropwise to the mixture that has just been cooled down, under vigorous magnetic stirring.

Step 5):

After full addition of the metal, the synthesis bottle is closed again and left under magnetic stirring for an additional 1 h. The final overall molar gel composition (solution A and B mixed) is 1 Si0 ₂ : 0.28 TPAOH: 0.06 Sn0 ₃ : 0.06 M’ ₂ 0: 40 H ₂ 0. Step 6):

The obtained synthesis mixture from step 5) is then placed in a static oven at 90°C for 43 h. Step 7):

The sample is removed from the oven after step 5), and cooled down to room temperature. The solid phase is then separated from the liquid phase using centrifugation. The solid is dispersed in distilled water and centrifugation is performed again. This washing procedure is repeated until the pH of the liquid separated from the solid phase is around 7-8.

Step 8):

The obtained solid sample is then dried in a static oven at 80°C overnight.

The dried sample retrieved is then subjected to the following calcination procedure: In ambient atmospheric conditions (composition of the atmosphere, and atmospheric pressure), the sample is placed in a muffle furnace. The furnace heats up from room temperature to 550°C in 5h, holds the temperature at 550°C for an additional 5h before the furnace is allowed to cool down to room temperature in 5h. The as-obtained sample from step 8) is called SnMFI.

Example 4 - MoMFI-4

Preparation of molybdenum (Mo) containing MFI zeolite by staged synthesis approach (metal sources (M and M’) were added to the amorphous material with a delay of 5h)

Step 1):

In a polypropylene synthesis bottle (125 ml_), solution A is prepared by adding 8.197 g of TPAOH (1M) and 11.191 g of double-distilled water, under agitation performed using a magnetic stirrer. To this solution A is then added drop-wise 6g of TEOS, under stirring performed by a magnetic stirrer. The solution should be water clear and liquid. Upon preparation, the gel might be slightly inhomogeneous, but the solution should end up being water-like during the ageing step (beginning of step 2)).

Step 2):

The bottle containing the solution prepared in step 1) is air-tightly closed with a cap. The as- made synthetic gel is left for ageing under magnetic stirring for 1 h, and then on an orbital shaker for an additional 18h. All the steps up to this point are performed at room temperature and ambient pressure.

Step 3):

The synthesis mixture is water-like at this point. The synthetic gel, still in its air-tightly closed bottle, is then subjected to static hydrothermal treatment at 90°C, for a duration of 5h.

Step 4):

The synthesis bottle is retrieved from step 3), and cooled down to room temperature under magnetic agitation, without opening the bottle. The synthesis mixture inside is still fully amorphous at this stage of the synthesis method. A solution B is prepared from 0.305 g of ammonium heptamolybdate tetra-hydrated (NH4)6Mq7q24, 4H ₂ 0, and 0.202g of sodium chloride dissolved in 3 mL of double-distilled water. The solution is hand-mixed until it becomes water-clear. Solution B is then added drop-wise to the mixture that has just been cooled down, under vigorous magnetic stirring.

Step 5):

After full addition of the metal, the synthesis bottle is closed again and left under magnetic stirring for an additional 1 h. The final overall molar gel composition (solution A and B mixed) is 1 Si0 ₂ : 0.28 TPAOH: 0.06 Mo0 ₃ : 40 H ₂ 0: 0.12 NaCI.

Step 6):

The obtained synthesis mixture from step 5) is then placed in a static oven at 90°C for 43 h. Step 7):

The sample is removed from the oven after step 5), and cooled down to room temperature. The solid phase is then separated from the liquid phase using centrifugation. The solid is dispersed in distilled water and centrifugation is performed again. This washing procedure is repeated until the pH of the liquid separated from the solid phase is around 7-8.

Step 8):

The obtained solid sample is then dried in a static oven at 80°C overnight.

The dried sample retrieved is then subjected to the following calcination procedure: In ambient atmospheric conditions (composition of the atmosphere, and atmospheric pressure), the sample is placed in a muffle furnace. The furnace heats up from room temperature to 550°C in 5h, holds the temperature at 550°C for an additional 5h before the furnace is allowed to cool down to room temperature in 5h. The as-obtained sample from step 8) is called MoMFI-3.

Example 5 - VMFI-1 to VMFI-4

Synthesis of vanadium (V) containing MFI zeolite by staged synthesis approach, using different alkali metals (metal source was added to the amorphous material with a delay of 5h).

Step 1):

In a polypropylene synthesis bottle (125 mL), solution A is prepared by adding 8.197 g of TPAOH (1M) and 11.194 g of double-distilled water, under agitation performed using a magnetic stirrer. To this solution A is then added drop-wise 6g of TEOS, under stirring performed by a magnetic stirrer. The solution should be water clear and liquid. Upon preparation, the gel might be slightly inhomogeneous, but the solution should end up being water-like during the ageing step (beginning of step 2)).

Step 2):

The bottle containing the solution prepared in step 1) is air-tightly closed with a cap. The as- made synthetic gel is left for ageing under magnetic stirring for 1 h, and then on an orbital shaker for an additional 18h. All the steps up to this point are performed at room temperature and ambient pressure.

Step 3):

The synthesis mixture is water-like at this point. The synthetic gel, still in its air-tightly closed bottle, is then subjected to static hydrothermal treatment at 90°C, for a duration of 5h.

Step 4):

The synthesis bottle is retrieved from step 3), and cooled down to room temperature under magnetic agitation, without opening the bottle. The synthesis mixture inside is still fully amorphous at this stage of the synthesis method. A solution B is prepared from 0.183 g of lithium vanadate or 0.211 g of sodium vanadate or 0.239 g of potassium vanadate, or 0.401 g of Cesium vanadate (CsVCh), dissolved in 3 ml_ of double-distilled water. The solution is hand- shaken until it becomes water-clear. Solution B is then added drop-wise to the mixture that has just been cooled down, under vigorous magnetic stirring.

Step 5):

After full addition of the metal, the synthesis bottle is closed again and left under magnetic stirring for an additional 1 h. The final overall molar gel composition (solution A and B mixed) is 1 Si0 ₂ : 0.28 TPAOH: 0.03 V ₂ 0 ₅ : 0.03 M’ ₂ 0: 40 H ₂ 0.

Step 6):

The obtained synthesis mixture from step 5) is then placed in a static oven at 90°C for 43 h. Step 7):

The sample is removed from the oven after step 5), and cooled down to room temperature. The solid phase is then separated from the liquid phase using centrifugation. The solid is dispersed in distilled water and centrifugation is performed again. This washing procedure is repeated until the pH of the liquid separated from the solid phase is around 7-8.

Step 8):

The obtained solid sample is then dried in a static oven at 80°C overnight.

The dried sample retrieved is then subjected to the following calcination procedure: In ambient atmospheric conditions (composition of the atmosphere, and atmospheric pressure), the sample is placed in a muffle furnace. The furnace heats up from room temperature to 550°C in 5h, holds the temperature at 550°C for an additional 5h before the furnace is allowed to cool down to room temperature in 5h. The as-obtained sample from step 7) is called VMFI-1 in case lithium vanadate was used in step 4); VMFI-2 for sodium vanadate; VMFI-3 for potassium vanadate; and VMFI-4 for caesium vanadate.

Examples 6 and 7

The starting materials used in examples 6 and 7 are as follow: Tetraehtylorthosilicate (TEOS), 98%, from Aldrich

Tetrapropylammonium hydroxyl (TPAOH), 20 wt.% in water (1 M), from Alfa Aesar Sodium molybdate tetrahydrated (Na2MoC>4, 4H2O), 98%, from Alfa Aesar Aluminum nitrate (AI(N03)3, 9H20) from Alfa Aesar Double distilled water

These materials were used as received from manufacturers without any further purification.

The zeolite samples described in examples 6 and 7 are characterized by various methods as listed below:

Scanning electron microscopy (SEM):

Scanning electron microscopy images of examples after step h) were recorded using a MIRA\LMH (TESCAN) microscope, with an electron beam of 30 kV.

Powder X-ray diffraction (XRD):

Powder samples of zeolites obtained after step h) were measured using a PANalytical X’Pert Pro X-ray diffractometer equipped with a monochromator specific to CuKa radiation (l = 1.5418 A, 45 kV, 40 mA). Samples were measured from 3 to 70 ⁰ 2Q, with a step size of 0.016°.

Le Bail profile refinement of each XRD patterns was also performed.

Solid-state nuclear magnetic resonance of silicon ( ²⁹ Si MAS NMR):

Powder samples obtained after step h) are packed into zirconia rotor of 4 mm outer diameter spun at 12 kHz, in a Bruker Avance lll-HD 500 (11.7 T) spectrometer operating at 99.3 MHz. 29Si MAS NMR spectra are recorded from a single pulse excitation (30° flip angle), used with a recycle delay of 30 s. {1 H} 29Si cross-polarization (CP) solid-state MAS NMR was acquired using a contact time of 5 ms and a recycle delay of 2 s. Chemical shifts were referenced to tetramethyl silane (TMS).

1H MAS NMR of dehydrated zeolite samples

Zeolite samples were dehydrated at 200 °C overnight and directly measured in MAS NMR. Measurement performed using liquid water as a reference for the amount of hydrogen. Error for the calculated absolute values: less than 0.5 mmol/g.

Scanning transmission electron microscopy with energy dispersive X-Ray analysis (STEM/EDS) and High Angle Annular Dark Field imaging (HAADF-STEM):

Experiments were performed on an Analytical double (objective and probe) corrected JEOL ARM200CF equipped with a 100 mm Centurio EDS detector and a Quantum GIF for the EELS. A probe of 0.1 nm was used to scan the sample in STEM mode and Bright Field and High Angle Annular Dark Field detectors were simultaneously employed for imaging. Camera length was 8 cm, and two different accelerating voltages of 200 and 80 kV were used in the STEM mode for imaging and chemical analysis respectively. Owing to the enhanced Z-contrast developed at 200 kV, this configuration was used for imaging and a high-speed scanning protocol (10 psec/px) was employed to prevent sample degradation under the electron beam. To avoid such degradation, STEM-EDS analytical assays were carried out at 80 kV, with a scanning speed of 3 ps/px for a mean duration of 60 minutes. A cross-correlation algorithm implemented in the Jeol Analysis Station software was applied every 30 seconds to compensate for the special drift occurring during the test. The microstructure of samples was checked before and after each EDS scan.

Inductively coupled plasma (ICR) optical emission spectrometry was used to determine the chemical compositions using a Varian ICP-OES 720-ES. The Si/AI molar ratio or the Si/M molar ratio are determined using the said method.

Example 6 - Mo Silicalite-1

Preparation of molybdenum (Mo) containing Silicalite-1 zeolite with a fully crystalline, purified and calcined sample as starting material

Steps 1) to 4) correspond to the normal synthesis of the Silicalite-1 zeolite. Steps 5) to 10) correspond to the isomorphous substitution of the MFI with molybdenum.

Step 1):

In a polypropylene synthesis bottle (125 ml_), solution A is prepared by adding 24.591 g of TPAOH (1M) and 42.581 g of double-distilled water, under agitation performed using a magnetic stirrer. To this solution A is then added drop-wise 18.0 g of TEOS, under stirring performed by a magnetic stirrer. The solution should be water clear and liquid. Upon preparation, the gel might be slightly inhomogeneous, but the solution should end up being water-like during the ageing step (beginning of step 2). The molar composition of the as- prepared precursor suspension is the following: 0.28 TPAOH: 1 S1O2: 40 H2O

Step 2):

The bottle containing the solution prepared in step 1) is air-tightly closed with a cap. The as- made synthetic suspensions are left for ageing under magnetic stirring for 1 h, and then on an orbital shaker (225 rpm) for an additional 18h. All the steps up to this point are performed at room temperature and ambient pressure. Step 3):

The synthesis mixture is water-like at this point. The synthetic mixture, still in its air-tightly closed bottle, is then subjected to static hydrothermal treatment at 90°C, for a duration of 48h.

Step 4):

The sample is removed from the oven after step 3), and cooled down to room temperature. The solid phase is then separated from the liquid phase using centrifugation. The solid is dispersed in distilled water and centrifugation is performed again. This washing procedure is repeated until the pH of the liquid separated from the solid phase is around 7-8.

Step 5) correspond to step 2) and 3):

The obtained solid sample is then dried in a static oven at 80°C overnight.

The dried sample retrieved is then subjected to the following calcination procedure: In ambient atmospheric conditions (composition of the atmosphere, and atmospheric pressure), the sample is placed in a muffle furnace. The furnace heats up from room temperature to 550°C in 5h, holds at 550°C for an additional 5h, before the furnace is allowed to cool down to room temperature in 5h.

Step 6):

300 mg of the obtained purely siliceous and fully crystalline Silicalite-1 zeolite that was calcined in step 5), is then introduced in a sealed container containing a solution composed of 0.208 g of sodium molybdate (Na2MoC>4, 4H2O) dissolved in 8.0 g of distilled water.

Step 7) (corresponds to step 5):

The obtained suspension is mixed with a magnetic stirrer for 1h at room temperature.

Step 8) (corresponds to step 6):

The obtained suspension from step 7) is then placed in a static oven at 90°C for 96h.

Step 9) (corresponds to step 7):

The sample is removed from the oven after step 8), and cooled down to room temperature. The solid phase is then separated from the liquid phase using centrifugation. The solid is dispersed in distilled water and centrifugation is performed again. This washing procedure is repeated several times (around 3 to 6 times) to remove any unreacted species.

Step 10) (corresponds to step 8):

The obtained solid sample is then dried in a static oven at 80°C overnight. The dried sample retrieved is then subjected to the following calcination procedure: In ambient atmospheric conditions (composition of the atmosphere, and atmospheric pressure), the sample is placed in a muffle furnace. The furnace heats up from room temperature to 550°C in 5h, holds at 550°C for an additional 5h, before the furnace is allowed to cool down to room temperature in 5h. The as-obtained sample from step 8) is called Mo-Silicalite-1.

After step 10) the Mo-containing nanosized materials were ion-exchanged with a solution of 0.2 M of NH4CI (1 h at 25°C), washed with dd H2O and calcined at 550°C to eliminate the NH3 and obtain the zeolite nanocrystals in acidic form. This procedure was repeated twice.

Example 7 - Mo-ZSM-5

Preparation of molybdenum (Mo) containing ZSM-5 zeolite with a fully crystalline, purified and calcined ZSM-5 zeolite as starting material (sample Mo-ZSM-5)

Steps 1) to 4) correspond to the synthesis of the ZSM-5 zeolite. Steps 5) to 10) correspond to the isomorphous substitution of the ZSM-5 with molybdenum.

Step 1):

In a polypropylene bottle (125 ml_), solution A is prepared by adding 41.804 g of TPAOH (1M) and 0.346 g of aluminium nitrate (AI(NC>3)3, 9H2O), under agitation using a magnetic stirrer until complete dissolution of the salt. To this solution A is then added drop-wise 24.0 g of TEOS, under stirring using a magnetic stirrer. The solution becomes water clear after 30 min (beginning of step 2). The molar composition of the as-prepared precursor suspension is the following: 0.357 TPAOH: 0.004 Al ₂ 0 ₃ : 1 Si0 ₂ : 16.189 H ₂ 0

Step 2):

The bottle containing the precursor suspension prepared in step 1) is air-tightly closed with a cap. The as-made synthetic suspensions are left foraging on a magnetic stirrer for 1 h, and then on an orbital shaker for an additional 18h (225 rpm). All the steps up to this point are performed at room temperature and ambient pressure.

Step 3):

The precursor suspension is water-like at this point. Then it is transferred into Teflon-lined autoclaves, and subjected to static hydrothermal treatment at 180°C, for a duration of 72h.

Step 4):

The sample is removed from the oven after step 3), and cooled down to room temperature. The solid phase is then separated from the liquid phase using centrifugation. The solid is dispersed in distilled water after reaching the pH of the liquid separated from the solid phase of 7-8.

Step 5):

The obtained solid sample is then dried in a static oven at 80°C overnight.

The dried sample retrieved is then subjected to the following calcination procedure: In ambient atmospheric conditions (composition of the atmosphere, and atmospheric pressure), the sample is placed in a muffle furnace and heated at 550°C in 5h, holds at 550°C for an additional 5h and cooled down to room temperature in 5h. The ZSM-5 zeolite has a Si/AI ratio of 112 based on ICP analysis.

Step 6):

1.2 g of the fully crystalline calcined ZSM-5 zeolite (after step 5), is then introduced in a sealed container containing a solution composed of 0.800 g of sodium molybdate (Na2MoC>4, 4H2O) dissolved in 25 ml_ of double-distilled water.

Step 7):

The obtained suspension is mixed with a magnetic stirrer for 1h at room temperature.

Step 8):

The obtained suspension from step 7) is then placed in a static oven at 90°C for 9 days.

Step 9):

The sample is removed from the oven after step 8), and cooled down to room temperature. The solid phase is then separated from the liquid phase using centrifugation. The solid is dispersed in distilled water and purified by centrifugation again. This washing procedure is repeated several times (3 to 6 times) to remove any unreacted species.

Step 10):

The obtained solid sample is then dried in a static oven at 80°C overnight.

The dried sample retrieved is then subjected to the following calcination procedure: In ambient atmospheric conditions (composition of the atmosphere, and atmospheric pressure), the sample is placed in a muffle furnace and heated at 550°C in 5h, holds at 550°C for an additional 5h and cooled down to room temperature in 5h. The as-obtained sample from step 8) is called Mo-ZSM-5.

Characterizations of Mo-Silicalite-1 (example 6) and Mo-ZSM-5 samples (example 7): The XRD pattern together with the ²⁹ Si MAS NMR spectra of samples Mo-Silicalite-1 and Mo- ZSM-5 show that Mo is perfectly substituted on the MFI structure.

The ¹ H MAS NMR of dehydrated zeolite samples allows calculating a ratio of the concentration of surface OH when Mo is present or not. It appears that the ratios are the following: nOH(Silicalite-l) / nOH(Mo-Silicalite-l) = 3.6 nOH(ZSM-5) / nOH(Mo-ZSM-5) = 2.8

There is consequently respectively 3.6 and 2.8 OH groups in the initial Mo free samples for every OH groups in the corresponding Mo-containing sample.

Example 8

Preparation of a comparative example by classical impregnation of a ZSM-5 with Mo Mo-containing ZSM-5 catalyst was prepared via impregnation of the required amount of ammonium heptamolybdate solution onto H-form of ZSM-5 catalyst with Si/AI ratio of 25 via incipient wetness, followed by drying at 393 K for 3 hours and calcination at 823 K for 6 hours in flowing air. Nominal molybdenum loading (wt.% of metal-based on the total weight of the catalyst) was targeted at 3 wt.%.

Before the catalytic test, the above material was ion-exchanged with a solution of 0.2M of NH4CI (1 h at 25°C), washed with dd H2O and calcined at 550°C to eliminate the NH3 and obtain the zeolite nanocrystals in acidic form. This procedure was repeated twice.

Example 9

This example is very similar to example 7 apart from that the starting material was a commercial zeolite ZSM-5 supplied by Zeolyst (CBV CBV 5524G) as for comparative sample 3.

Step 1):

The commercial zeolite ZSM-5 Si/AI=25 supplied by Zeolyst company in ammonia form was subjected to the following calcination procedure: In ambient atmospheric conditions (composition of the atmosphere, and atmospheric pressure), the sample is placed in a muffle furnace and heated at 550°C in 5h, holds at 550°C for an additional 5h and cooled down to room temperature in 5h.

Step 2): 1.2 g of calcined ZSM-5 zeolite (after step 1), is then introduced in a sealed container containing a solution composed of 0.800 g of sodium molybdate (Na2MoC>4, 4H2O) dissolved in 25 ml_ of double-distilled water.

Step 3):

The obtained suspension is mixed with a magnetic stirrer for 1h at room temperature.

Step 4):

The obtained suspension from step 3) is then placed in a static oven at 90°C for 9 days.

Step 5):

The sample is removed from the oven after step 4), and cooled down to room temperature. The solid phase is then separated from the liquid phase using centrifugation. The solid is dispersed in distilled water and purified by centrifugation again. This washing procedure is repeated several times (3 to 6 times) to remove any unreacted species.

Step 6):

The obtained solid sample is then dried in a static oven at 80°C overnight.

The dried sample retrieved is then subjected to the following calcination procedure: In ambient atmospheric conditions (composition of the atmosphere, and atmospheric pressure), the sample is placed in a muffle furnace and heated at 550°C in 5h, holds at 550°C for an additional 5h and cooled down to room temperature in 5h. The as-obtained sample from step 8) is called Mo-ZSM-5.

Step 7)

Before the catalytic test, the Mo-containing nanosized materials were ion-exchanged with a solution of 0.2M of NH ₄ CI (1 h at25°C), washed with dd H ₂ O and calcined at550°C to eliminate the NH ₃ and obtain the zeolite nanocrystals in acidic form. This procedure was repeated twice.

Example 10

Step 1):

A clear aqueous silicate suspension A was prepared by mixing 12 g of TEOS with 16.4 g of TPAOH (20% solution in water). The clear aqueous silicate suspension A was stirring at room temperature (i.e. 25°C).

A clear aqueous suspension B was prepared by mixing 1.1 g of sodium molybdate dehydrate (Na ₂ Mo0 ₄ , 2H2O) in 28.2 of dd H ₂ 0.

Suspension B was added dropwise to suspension A. During the addition, suspension A was maintained at room temperature while being vigorously stirred. The pH of the resulting clear aqueous suspension was about 12. The resulting clear aqueous suspension had the following molar composition:

0.08 MoOs : Si0 ₂ : 0.28 TPA ₂ 0 : 0.08 Na ₂ 0 : 40H ₂ O (I).

Step 2):

The resulting clear aqueous suspension was then aged by magnetic stirring for 3 hours at room temperature and by orbital stirring for 14 hours at room temperature.

Step 3):

Then, the hydrothermal crystallization was conducted at 90°C for 48 hours.

Step 4):

The solid was separated and recovered by high-speed centrifugation (20000 rpm, 10 min) and several washes with hot double distilled water (heated at 100°C for 30 min) until the pH of the remaining water was about 7.5.

Step 5):

The obtained solid sample is then dried in a static oven at 80°C overnight.

The dried sample retrieved is then subjected to the following calcination procedure: In ambient atmospheric conditions (composition of the atmosphere, and atmospheric pressure), the sample is placed in a muffle furnace. The furnace heats up from room temperature to 550°C in 5h, holds at 550°C for an additional 5h, before the furnace is allowed to cool down to room temperature in 5h.

Step 6)

Before the catalytic test, the Mo-containing nanosized materials were ion-exchanged with a solution of 0.2M of NH4CI (1 h at25°C), washed with dd H ₂ 0 and calcined at550°C to eliminate the NH ₃ and obtain the zeolite nanocrystals in acidic form. This procedure was repeated twice.

Process comprising an oxyhalogenation reactor and a synthesis reactor

Example 11

A setup comprising oxyhalogenation reactor and synthesis reactor was used for the methane conversion. The methane oxyhalogenation reactor was loaded with 10g of monoclinic Zr0 ₂ catalyst pre-treated with 5M sulphuric acid for 6h; before loading, the catalyst was crushed and seized between 35-45 mesh screens. The oxyhalogenation reactor is operated at 0.3 MPa and 400°C. The synthesis reactor was loaded with 10g of SSZ-39 zeolite having Si/AI atomic ratio of 10 (SAR of 20, as determined by TPD analysis); before loading, the catalyst was crushed and seized between 35-45 mesh screens. The synthesis reactor is operated at 0.2 MPa and 400°C. In between the reactors, a cylinder with 3A sieves was installed for flow pre-drying purpose. The flow of N ₂ /CH ₄ /0 ₂ /HCI ~ 1/10/2/1 mol. with WHSV of 0.5 IT ¹ (of ChU/catalyst in the oxyhalogenation reaction was used). The results are shown in Table 5.

Example 12

A setup comprising oxyhalogenation reactor and synthesis reactor was used for the methane conversion. The methane oxyhalogenation reactor was loaded with 10g of Ce0 ₂ catalyst pre treated with 5M sulphuric acid for 6h; before loading, the catalyst was crushed and seized between 35-45 mesh screens. The oxyhalogenation reactor is operated at 0.4 MPa and 400°C. The synthesis reactor was loaded with 10g of M FI-type zeolite having Si/AI atomic ratio of 500 (SAR of 1000, as determined by TPD analysis); before loading, the catalyst was crushed and seized between 35-45 mesh screens. The synthesis reactor is operated at 0.2 MPa and 280°C. In between the reactors, a cylinder with 3A sieves was installed for flow pre-drying purpose. The flow of N ₂ /CH ₄ /0 ₂ /HCI ~ 1/10/2/1 mol. with WHSV of 2 IT ¹ (of CH ₄ /catalyst in the oxyhalogenation reaction was used). The results are shown in table 4.

Example 13

A setup comprising oxyhalogenation reactor, synthesis reactor, and cracking reactor was used for the methane conversion. The methane oxyhalogenation reactor was loaded with 10g of Ce0 ₂ catalyst pre-treated with 5M sulphuric acid for 6h; before loading, the catalyst was crushed and seized between 35-45 mesh screens. The oxyhalogenation reactor is operated at 0.4 MPa and 400°C. The synthesis reactor was loaded with 10g of MFI-type zeolite having Si/AI atomic ratio of 500 (SAR of 1000, as determined by TPD analysis); before loading, the catalyst was crushed and seized between 35-45 mesh screens. The synthesis reactor is operated at 0.2 MPa and 280°C. The cracking reactor was loaded with 10g of MFI-type zeolite having Si/AI atomic ratio of 280 (SAR of 560, as determined by TPD analysis); before loading, the catalyst was crushed and seized between 35-45 mesh screens. The synthesis reactor is operated at 0.2 MPa and 480°C. The flow of N ₂ /CH ₄ /0 ₂ /HCI ~ 1/10/2/1 mol. with WHSV of 2 hr ¹ (of CH ₄ /catalyst in the oxyhalogenation reaction was used). The results are shown in table 5.

Example 14

A setup comprising oxyhalogenation reactor, synthesis reactor, and metathesis reactor was used for the methane conversion. The methane oxyhalogenation reactor was loaded with 10g of monoclinic Zr0 ₂ catalyst pre-treated with 5M sulphuric acid for 6h; before loading, the catalyst was crushed and seized between 35-45 mesh screens. The oxyhalogenation reactor is operated at 0.3 MPa and 400°C. The synthesis reactor was loaded with 10g of SSZ-39 zeolite having Si/AI atomic ratio of 10 (SAR of 20, as determined by TPD analysis); before loading, the catalyst was crushed and seized between 35-45 mesh screens. The synthesis reactor is operated at 0.2 MPa and 400°C. In between the oxyhalogenation and synthesis reactors, a cylinder with 3A sieves was installed for flow pre-drying purpose.

The metathesis catalyst was WO ₃ deposited on S1O ₂ with a loading of 5 wt.%. Before the test, the metathesis catalyst was pre-activated at 525°C in the flow of N2 for 5 hours. In between the synthesis and metathesis reactors, two consequent cylinders with pre-dried soda lime granules and 3A sieves were installed for HCI removal and pre-drying purpose. The metathesis reactor is operated at 0.2 MPa and 290°C. The flow of N ₂ /CH ₄ /O ₂ /HCI ~ 1/10/2/1 mol. with WHSV of 0.5 h ¹ (of ChU/catalyst in the oxyhalogenation reaction was used). The results are shown in table 5.

Table 5 presents the results of examples 11 to 14.

¹ Product distribution is calculated from the assumption of 100% of methane converted ² Calculated from the carbon mass balance

It can be seen from the examples that the total selectivity to C2-C5 olefins is found to be at least 50 % for examples 11, 12 and 14, and at least 45 % for example 13.