Background and Summary

BACKGROUND OF THE INVENTION

A. Field of the Invention

Present invention generally concerns a novel use of an adapted electrolytic apparatus to manufacture heteroatom-substituted zeolites (heteroatom zeolite), for instance Sn- zeolites, Zn-zeolites, Ti-zeolites, Fe-zeolites or Al -zeolites with a higher metal load and the method of use. More particularly it relates to heteroatom zeolites that are the reaction product of gradual metal incorporation in zeolites during the zeolite synthesis process the metal originating from an in-situ anodic oxidation.

B. Description of the Related Art

Zeolites are a class of inorganic microporous materials with a set of properties that open a vast horizon of various applications for them as adsorbents, membranes (fillers), ionexchangers, or catalysts. Incorporating different metals into a zeolite framework is one of the possible ways to provide accurate control of resulting properties.

However, the state of the art design of zeolite with desired metal loading has many complications due to the nature of zeolite synthesis. Therefore a universal tool is still missing to create zeolite structures with tuned metal incorporation performance.

There is thus a need in the art for loading up desired metal from the bottom-up (in synthesis) in a zeolite synthesis process.

Here, we successfully combined in-situ metal anodic oxidation with the zeolite synthesis process for the first time.

As a result, Sn-, A1-, Zn- and Fe-MFI zeolites, Sn-BEA, Sn-Al-BEA, and Sn-, Ti-CHA, as well as Sn-APO-5 with an extreme metal loading were synthesized. The high-loaded tin-containing materials synthesized by Electro-Assisted Synthesis (EAS) of present invent have a particularly suitable catalytic activity for the conversion of small sugars.

SUMMARY OF THE INVENTION

The present invention solves the problems of the related art by introducing gradual concentrations of and control over heteroatom release and thus its incorporation in the zeolite during the zeolite synthesis process opposed to filling a metal precursor at the start in a batch reactor.

In accordance with the purpose of the invention, as embodied and broadly described herein, the invention is broadly drawn to heteroatom zeolite that is the reaction product of combined electro-assisted metal precursors or heteroatom oxidation with zeolite synthesis and in particular to such heteroatom zeolite that comprises as heteroatoms Sn, Zr, Hf, Nb, B, Fe, Al, Ti, Zn or Ta or a combination thereof

In one aspect of the invention concerns zeolite manufacture apparatus for zeolite synthesis combined with anodic oxidation. This the apparatus comprises a closed reactor with an inner wall that is resistant to high pH region, for instance a pH of 10 or above. This reactor comprises a stirring device for moving the reaction medium, a cathode and an anode for anodic oxidation. An external circuit connects the anode by an electro-conductive guidance to a voltage generator or voltage source and that connects the cathode by another electro-conductive guidance to the voltage generator or voltage source to induce a anodecathode voltage and apparatus. Further the apparatus comprises a heating means for heating the reaction medium

In still another aspect of the invention, concerns a molecular sieve material manufacturing method, whereby an aqueous reaction mixture comprising a source of silicon oxide and mineralizing agent is in contact with an anode and cathode and whereby the reaction mixture is subjected to a crystallization conditions sufficient to form crystals of the molecular sieve material while subjecting the anode to electro-assisted anodic oxidation Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.

The invention provides a way to use an apparatus for heteroatom zeolite manufacturing, wherein the apparatus comprising an electrolytic cell, a closed reactor with an inner wall that is resistant to both low and high pH regions of a pH 1 to pH 14, whereby the reactor comprises 1) a cathode and 2) an anode, and whereby an external circuit connects the anode by an electro-conductive guidance to a voltage generator or voltage source and that connects the cathode by another electro-conductive guidance to the voltage generator or voltage source to induce a anode-cathode voltage and apparatus further comprising a heating means for heating the reaction medium and whereby the heating controller is functionally connected to the heating means and the function generator to generate different types of electrical voltage waveforms in AC mode on said the anode and/or cathode characterised in that the voltage generator is connected to a tuned amplifier to tune the anodic oxidation.

This use of the apparatus can be for manufacturing heteroatom zeolite combined with anodic oxidation, wherein the apparatus comprising a closed reactor with an inner wall that is resistant to both low and high pH regions of a pH 1 to pH 14, whereby the reactor comprises 1) a cathode and 2) an anode for anodic oxidation, and whereby an external circuit connects the anode by an electro-conductive guidance to a voltage generator or voltage source and that connects the cathode by another electro-conductive guidance to the voltage generator or voltage source to induce a anode-cathode voltage and apparatus further comprising a heating means for heating the reaction medium.

This invention can be used in conjunction with a stirring device in the reactor for moving the reaction medium. Furthermore the apparatus in use can comprise a heating controller and a function generator. Furthermore the apparatus in use can comprise a seal to confine the reactor container from the ambient atmosphere and a gas pump to pressurize said reactor container.

A further disadvantageous aspect is also, that the anode and/or cathode is made of stainless steel. In a further embodiment of the invention, the anode and/or cathode comprises a metal of the group consisting of Sn, Zn, Fe, Ti, B or Al or combination thereof.

With respect to method of use of the apparatus, it is noted that it is advantageous if the reaction mixture comprising hydroxide ions as mineralizing agent.

With respect to method of use of the apparatus, it is noted that it is also advantageous if the structure directing agent is organic.

With respect to method of use of the apparatus, it is noted that it is also advantageous if during zeolite synthesis process silica oxide precursors are exposed to a heteroatom precursor from anodic oxidation or a mixture of different heteroatom precursors from anodic oxidation.

According to the present invention there is provided a method of use of the apparatus, whereby incorporation of the oxidation product originating from an in-situ anodic oxidation in the zeolites during the manufacturing process.

According to the present invention there is also provided a method of use of the apparatus, whereby the reaction product from the anodic oxidation is under control by a voltage bias with a waveform on the in the reaction mixture immersed electrodes.

According to the present invention there is also provided a method of use of the apparatus, whereby the reaction is a main working temperature, 80 to 160°C.

According to the present invention there is also provided a method of use of the apparatus, whereby the reaction is at a temperature, between 15°C to 250°C.

According to the present invention there is also provided a method of use of the apparatus, whereby the reaction mixture is in a base media.

According to the present invention there is also provided a method of use of the apparatus,, whereby the reaction mixture is in an acid media.

The present invention also relates to manufacturing method, to manufacture a heteroatom zeolite, whereby providing an aqueous reaction mixture comprising a source of silicon oxide and mineralizing agent and a structure directing agent in contact with an anode and cathode and subjecting the reaction mixture to a crystallization conditions sufficient to form crystals of the zeolite material while subjecting the anode to electro-assisted anodic oxidation, whereby during zeolite synthesis process silica oxide precursors are exposed to a heteroatom precursor from in-situ electro-assisted oxidation, in particular in which some or all of the silicon (Si) atoms in the zeolite framework are replaced by any metal of the group tin (Sn), Boron (B), Zirconium (Zr), Titanium (Ti), Aluminum (Al) and Iron (Fe) or a combination thereof.

This method allows to manufacture a heteroatom zeolite with tetrahedral framework of the group consisting of MFI, BEA, CHA zeolites, to manufacture a Sn-containing or Zn/Sn-containing heteroatom zeolite and to manufacture a Sn-containing or Zn/Sn- containing heteroatom zeolite with tetrahedral framework of the group consisting of MFI, BEA, CHA zeolites. This method is particularly suitable to manufacture a mixed Zn/Sn-containing MFI and to manufacture a heteroatom zeolite with silica on metal ration in said heteroatom zeolite below 30.

It has been found that particular adaptations at the method can be used to tune different specific properties to the heteroatom zeolite such as the reaction mixture comprising hydroxide ions as mineralizing agent, the structure directing agent is organic, during the zeolite synthesis process silica oxide precursors are exposed to a heteroatom precursor from anodic oxidation or a mixture of different heteroatom precursors from anodic oxidation, incorporation of the oxidation product originating from an in-situ anodic oxidation in the zeolites during the manufacturing process, the reaction product from the anodic oxidation is under control by a voltage bias with a waveform on the in the reaction mixture immersed electrodes, the reaction is a main working temperature, 80 to 160°C, the reaction is at a temperature, between 15°C to 250°C, the reaction mixture is in a base media, the reaction mixture is in an acid media. whereby an alternating voltage bias energizing of said the oxidation anode, a waveform in sine/square/triangle/pulsed energizing of said the oxidation anode is used, tuning of the electrode energizing is controlled in such way that the release timing and concentration heteroatom precursors is during the zeolite crystallization so regulated in order to avoid nucleation delays and stimulate heteroatom incorporation, the silicon oxide source is partially or fully replaced by an aluminium oxide and a phosphorus oxide source.

In another aspect, the present invention provides that this molecular sieve material or heteroatom zeolite obtained from the manufacturing method, characterised in that it is the reaction product of gradual metal incorporation in zeolites during the zeolite synthesis process the metal originating from an in-situ anodic oxidation whereby gradual metal incorporation evidenced by at least 60% of incorporated heteroatoms resemble Lewis acidity (LAS density) as defined FT-IR of adsorbed CD3CN],

According to the present invention there is provided a Zn/Sn-containing heteroatom zeolite, characterised in that heteroatom zeolite is the reaction product of combined electro-assisted metal precursors or heteroatom oxidation with zeolite synthesis.

According to the present invention there is also provided a Zn/Sn-containing heteroatom zeolite, characterised in that heteroatom zeolite is the reaction product of combined electro-assisted metal precursors or heteroatom oxidation with zeolite synthesis, whereby providing an aqueous reaction mixture comprising a source of silicon oxide and mineralizing agent and a structure directing agent in contact with an anode and cathode and subjecting the reaction mixture to a crystallization conditions sufficient to form crystals of the zeolite material while subjecting the anode to electro-assisted anodic oxidation, whereby during zeolite synthesis process silica oxide precursors are exposed to a heteroatom precursor from in-situ electro-assisted oxidation. In some embodiments, this Zn/Sn-containing heteroatom zeolite is with tetrahedral framework and of the group consisting of MFI, BEA, CHA zeolites and some embodiments, this Zn/Sn-containing heteroatom zeolite is a mixed Zn/Sn-containing MFI.

A Zn/Sn-containing heteroatom zeolite with an extreme metal loading of Si/metal below 30, is obtained by the method and use of the apparatus of present invention.

The present invention also provide such heteroatom zeolite, characterised in that this heteroatom zeolite is the reaction product of electro-assisted heteroatom zeolite synthesis by combining a silica precursor with metal precursor or heteroatom precursor from in- situ anodic oxidation.

The present invention also provide such heteroatom zeolite, characterised in that this heteroatom zeolite is the reaction product of electro-assisted synthesis combining zeolite synthesis with in-situ anodic oxidation of metal precursors.

The present invention also provide such heteroatom zeolite, characterised in that this heteroatom zeolite is the reaction product of combining zeolite synthesis with in-situ anodic oxidation of metal precursors with gradual incorporation of the metal originating from an in-situ anodic oxidation in zeolites during the zeolite synthesis process.

The present invention also provide such heteroatom zeolite, characterised in that this heteroatom zeolite is the reaction product electro-assisted synthesis as described here above, and from a reaction in an electrochemical reactor with anodic oxidation controlled by a voltage bias on immersed electrodes.

This heteroatom zeolite can be characterised in it is that it is the reaction product from electro-assisted synthesis described here above, and from a reaction in an electrochemical reactor with anodic oxidation based release of heteroatom by a voltage bias on immersed electrodes.

This heteroatom zeolite can be characterised in it is that it is the reaction product from electro-assisted synthesis described here above, but in a watery medium and at room temperature, 80 to 160°C.

This heteroatom zeolite can be characterised in it is that it is the reaction product from electro-assisted synthesis described here above, but in a watery medium and at a temperature, between 15°C to 250°C

This heteroatom zeolite can be characterised in it is that it is the reaction product from electro-assisted synthesis described here above, but in a watery in a hydroxide medium. This heteroatom zeolite can be characterised in it is that it is the reaction product from electro-assisted synthesis described here above , but in a watery in a base media.

This heteroatom zeolite can be characterised in it is that it is the reaction product from electro-assisted synthesis described here above, but in a watery in acid media.

This heteroatom zeolite can be characterised in it is that it is the reaction product from electro-assisted synthesis described here above, and waveform in sine/square/triangle/pulsed energizing of said oxidation anode.

This heteroatom zeolite can be characterised in that it is the reaction product from electroassisted synthesis described here above, and anodic oxidation controlled by an alternating voltage bias on immersed electrodes.

18. The heteroatom zeolite characterised in it is that it is the reaction product from electro-assisted synthesis described here above, whereby by tuning of the electrode energizing is controlled in such way that the release timing and concentration heteroatom precursors is during the zeolite crystallization so regulated in order to avoid nucleation delays and stimulate heteroatom incorporation.

According to the present invention there is provided he heteroatom zeolite of present invention, characterised in that it is the reaction product of gradual metal incorporation in zeolites during the zeolite synthesis process the metal originating from an in-situ anodic oxidation whereby gradual metal incorporation is evidenced by at least 60% of incorporated heteroatoms resemble Lewis acidity (LAS density) as defined FT-IR of adsorbed CD3CN.

In a further embodiment of the invention, the metal loaded heteroatom zeolite of present invention is used for the catalytic conversion of sugars to lactic acid.

In a further embodiment of the invention, the metal loaded heteroatom zeolite of present invention is used for the catalytic isomerisation of sugars.

In a further embodiment of the invention, the metal loaded heteroatom zeolite of present invention is used for the catalytic oxidation of keton.

Some of the techniques described above may be embodied as a method of use of the apparatus, whereby providing an aqueous reaction mixture comprising a source of silicon oxide and mineralizing agent and a structure directing agent in contact with an anode and cathode and subjecting the reaction mixture to a crystallization conditions sufficient to form crystals of the zeolite material while subjecting the anode to electro-assisted anodic oxidation, whereby during zeolite synthesis process silica oxide precursors are exposed to a heteroatom precursor from in-situ electro-assisted oxidation. This method of use of the apparatus is particularly suitable to manufacture a heteroatom zeolite with tetrahedral framework of the group consisting of MFI, BEA, CHA zeolites.

The use of this apparatus most practical to have some or all of the silicon (Si) atoms in the zeolite framework are replaced by any metal of the group tin (Sn), Boron (B), Zirconium (Zr), Titanium (Ti), Aluminum (Al) and Iron (Fe) or a combination thereof or to manufacture a Sn-containing or Zn/Sn-containing heteroatom zeolite with tetrahedral framework of the group consisting of MFI, BEA, CHA zeolites.

In another aspect, the present invention provides that this apparatus is used according to any one of techniques here above, to manufacture a mixed Zn/Sn-containing MFI.

In yet another aspect, the present invention provides that this apparatus is used according to any one of techniques here above, to manufacture a heteroatom zeolite with silica on metal ration in said heteroatom zeolite below 30.

Detailed Description DETAILED DESCRIPTION OF EMBODIMENTS OF THE

INVENTION

The following detailed description of the invention refers to the accompanying drawings. The same reference numbers in different drawings identify the same or similar elements. Also, the following detailed description does not limit the invention. Instead, the scope of the invention is defined by the appended claims and equivalents thereof.

Several documents are cited throughout the text of this specification. Each of the documents herein (including any manufacturer’s specifications, instructions etc.) are hereby incorporated by reference; however, there is no admission that any document cited is indeed prior art of the present invention.

The present invention will be described with respect to particular embodiments and with reference to certain drawings but the invention is not limited thereto but only by the claims. The drawings described are only schematic and are non-limiting. In the drawings, the size of some of the elements may be exaggerated and not drawn to scale for illustrative purposes. The dimensions and the relative dimensions do not correspond to actual reductions to practice of the invention.

Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.

Moreover, the terms top, bottom, over, under and the like in the description and the claims are used for descriptive purposes and not necessarily for describing relative positions. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other orientations than described or illustrated herein.

It is to be noticed that the term “comprising”, used in the claims, should not be interpreted as being restricted to the means listed thereafter; it does not exclude other elements or steps. It is thus to be interpreted as specifying the presence of the stated features, integers, steps or components as referred to, but does not preclude the presence or addition of one or more other features, integers, steps or components, or groups thereof. Thus, the scope of the expression “a device comprising means A and B” should not be limited to the devices consisting only of components A and B. It means that with respect to the present invention, the only relevant components of the device are A and B.

Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment, but may. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner, as would be apparent to one of ordinary skill in the art from this disclosure, in one or more embodiments.

Similarly it should be appreciated that in the description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this invention.

Furthermore, while some embodiments described herein include some but not other features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form different embodiments, as would be understood by those in the art. For example, in the following claims, any of the claimed embodiments can be used in any combination.

In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the invention may be practiced without these specific details. In other instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only.

Each and every claim is incorporated into the specification as an embodiment of the present invention. Thus, the claims are part of the description and are a further description and are in addition to the preferred embodiments of the present invention.

Each of the claims set out a particular embodiment of the invention.

The following terms are provided solely to aid in the understanding of the invention.

Definitions

A heteroatom zeolites - a class of inorganic microporous crystalline materials consisted from connected tetrahedrally-coordinated silicon oxides (in case of silicate zeolites) or aluminium and phosphorus oxides (in case of aluminophosphates) matrix, in which above mentioned elements are substituted by an atom of different nature. For example, tinsubstituted heteroatom zeolites: Sn-MFI, Sn-BEA, Sn-CHA are silicates. Another example is Sn-APO-5, an aluminophosphate. Heteroatom zeolites may contain more than one element in their framework. In present invention the heteroatom zeolite is a product directly obtained by a simultaneous combination of in situ anodic oxidation process and zeolite synthesis. Therefore, a heteroatom, nature of which is defined by the choice of an electrode material, is released to the synthesis solution (therefore, no dry gel is allowed) by an external electric power (with a change of an oxidation state from 0 to +N, where N=1 to 7) and the final obtained crystalline zeolite material contains the described metal in its framework.

Zeolite synthesis - a process of a crystalline zeolite phase formation from suitable sources, using silica source (including other zeolites materials but meaning the change of their phase after the complete of a synthesis procedure, e.g., interzeolite conversion or transformation), inorganic and/or organic structure directing agent (further described as “(in)OSDA”) and water. Synthesis of heteroatom-containing zeolites is known, and possible by adding a heteroatom source to the synthesis mixture, which usually implied by addition of metal salt (starting oxidation state > 0). Production of aluminophosphates starts from alumina, phosphorus, (in)OSDA and water, and can also be modified with heteroatom addition.

One common technical feature shared by MFI, BEA, and CHA zeolites (MFI Zeolite (Mordenite Framework Inverted), a BEA Zeolite (Beta Zeolite) and CHA Zeolite (Chabazite Framework)) is that they all have tetrahedral zeolite frameworks, which same basic structure they all share.

It is noticed that strong bases used herein have high pH values, usually 10 to 14 and strong acid have a pH of zero to 5, and preferably zero to 5.

EXAMPLES

Examples refer to figures and are also summarized in part in Table la and Table lb

Example 1 Sine waveform control of tin incorporation in MFI zeolite

The rationale for Sn-MFI hinges on the fact that the synthesis can be in hydroxide media - opposed to more tedious and dangerous fluoride media synthesis common for stannosilicates and the low synthesis temperatures (note that higher temperature EAS has also proven possible, e.g. see BEA later).

For a synthesis of a tin-containing MFI zeolite using an anodic metal oxidation technic, a small excess of a pure-siliceous gel was prepared by the following method. In a typical synthesis, 15.806 g of teraethoxisilane (later referred as TEOS) were mixed in a beaker with 19.276 g of N,N,N,N-tetrapropylammonium hydroxide (later referred as TPAOH) and 15.737 g of water. The mixture was stirred until the final batch composition was reached: Si:0.5TPAOH:20.0H20. For a general experiment, 34 g of the formed liquid gel were placed into a 50 ml Teflon-lined custom-made stainless steel autoclave. Before an experiment, two (in most cases identical) tin metal plates with a fixed surface area of 13.4 cm ² were washed in acetone, dried, weight, and attached to the internal pair of nuts connectors. Afterward, the autoclave was closed and put into a heating mantel at room temperature. In the end, the pair of terminals were attached to the wire connectors on the top part of the custom-made reactor. The synthesis starting time was counted from 60 °C indicated on the controlling thermocouple. The electricity was turned on simultaneously. Voltage, frequency, and a waveform, the crucial parameters of an EAS, were set before the start of an experiment on all electric signal generators with the following characteristics: 0.60 - 4.00 Vpp, 50 pHz, sine waveform. Crystallization has been conducted at 90 °C for 72 hours. After that, the reactor was cooled in an ice bath, opened; electrodes were washed in a flow of distilled water, dried, and weighed; a solid zeolitic product was separated from a cloudy solution or two-phase mixture by centrifugation (6200 rpm, 5-30 minutes), washed with Milli-Q water until the neutral pH with the same method, dried overnight at 60°C. Dried products were calcined with the following program: a slow temperature increase until 550 °C for 6 hours and with a hold for 9 hours at 550 °C.

Controlled tin release from an electrode surface in zeolite synthesis media is demonstrated in Fig IB, for alternating bias (‘AC’) modes. The standard electrode potential of tin hovers around E°(Sn ⁴⁺ /Sn°) = 0.245 V (7). This value likely corresponds to the most stable tin complex in aqueous solutions, i.e. Sn(OH)e ² ', which is found in the high pH range according to the Pourbaix diagram (2). For materials synthesized with nominal voltages close to this value, i.e. 0.6 Vpp (pp = peak to peak of the AC) and below, no changes in electrode weight before and after hydrothermal zeolite synthesis reaction was noticed, and accordingly, the Si/Sn ratio of the resulting material was large to be accurately measured (> Si/Sn = 800), effectively proving the synthesis of pure silicate. The anodic tin dissolution process for the sine waveform (circles) starts using voltages of 0.65 Vpp and above, and, as measured from the weight loss, increases quite predictable. The control in Sn release, expressed in release rate (= R _r in Fig. IB) is quite precise and reproducible, bearing in mind that, here, an alternating voltage bias was used, with very low frequency (50 pHz). Every 5.5 h, the electrode bias has fully changed potential along a sine, to allow both electrode surfaces to release Sn. Plotting the Vpp-controlled R _r versus the outcome of these zeolite syntheses in Fig. 1C reveals an excellent control over the Sn content in the final material (all crystalline), as seen from the Si/Sn ratios, which can surprisingly attain very low values (up to 30 for MFI) and thus very high heteroatom incorporation. We call this novel mode of control over metallosilicate heteroatom content ‘electroassisted synthesis’ or EAS. Not only EAS is able to control Sn incorporation by the push of a button based on a constant voltage, the accessible Si/Sn ratio range is also wider (lower values than in the art are achievable (3, -7)). EAS has its limits: in these specific conditions, for example at 1.5 Vpp (Fig. IB; CD3CN FT-IR - Fig. 2C) and higher, the results become more variable and sometimes, no zeolite forms (caption Fig IB). When the release is too great, the tin concentration can reach a threshold in the mother liquor that prevents (or tremendously slows) zeolite phase formation. Every process requires a certain amount of fine-tuning before it works as desired. The information in the present application is a best mode to provide a guidance and clear information to allow the skilled person, on the basis of the information as filed, from setting up to carry out such fine-tuning or tailoring and adapting the conditions as is necessary. The skilled person knows the parameters that are important, as set out in the description, and will adapt them within his or her competence.

Example 2 Tin incorporation in MFI zeolite controlled by electrode area and voltage bias

Preparations for a synthesis of Sn-MFI with controlled tin incorporation by electrode area were realized as in the Example 1 with following changes: various electrode area in the range from 6.7 to 30.8 cm ² .

A second mode of EAS control is found in the immersed surface of the electrodes. A series of experiments at constant voltage differences of 0.8 Vpp but with changing electrode (pair) areas shows a linearly dropping release rate (normalized per cm ² ) with increasing area, thus behaving in accordance to Faraday’s law of electrolysis (5). Going to larger surfaces thus slows down the rate per area, but overall, more Sn is released: for example comparing 22 cm ² electrodes to a 7 cm ² one, an absolute increase in release of 42% was found, corresponding to a 49% Sn richer zeolite product. Excessive metal release was also proven to happen by experiments at 2 and 4 Vpp with large-area electrodes (30.8 cm ² ) as no crystallization was seen, and visible particles had formed in suspension (6). These were confirmed to be metallic Sn (Fig. 2A). It seems likely that at an excess of anodic released ionic tin in hydroxide media, part of it migrates towards the counter-electrode, where reduction might take place (7). Control over Rr is thus crucial and should be chosen in the right range of parameters (Vpp, waveform, timing of bias applied).

Example 3 Square waveform control of tin incorporation in MFI zeolite

Preparations for a synthesis of Sn-MFI with square waveform were realized as in the Example 1 with following changes: square waveform. Further fine tuning these constant voltage bias modes for EAS is possible by using square waves or dedicated timing of releases. When using a low frequency sine function, e.g. of 0.7 Vpp as in Fig. IB, a part of the time, the voltage bias is below the standard redox potential of Sn (0.14 V for Sn° to Sn ²⁺ ) and certainly below the offset value for EAS (experimentally estimated at 0.3 V (0.6 Vpp)). Square wave experiments with the same frequency (50 pHz) were conducted at 0.7 - 0.8 Vpp for three days (Fig. IB, purple triangles). The R _r of the square wave was found to be much higher than for the sine wave experiments as the voltage bias of this wave function is always above the tin release threshold during the full synthesis period. To the contrary, the tin content in the formed zeolites was lower (Fig. 1C). We hypothesize that match between constantly released tin (vs bursts in sine) and a tin saturated silicon matrix was not reached causing low incorporation of the metal. To overcome this - next to working with sines with more controlled outcomes - timing the release only during certain stages of the zeolite crystallization process could be used.

Example 4 Concentration control of tin incorporation in MFI zeolite

By its nature, a high tin content in a zeolite lattice is tough to achieve. The bigger atomic radius of tin disturbs the positions of its neighbors, demands a different T-O-T bond angle, and renders the whole structure less thermodynamically stable with a large kinetic hurdle to incorporation (S). Usually, these materials require much longer synthesis times, if they even can overcome the immediate barrier of stabilization (9). Suprisingly by Electro- Assisted Synthesis (EAS) we could achieve a high tin content in a zeolite lattice. Mechanistically, 3 fundamental explanations for the controlled high Sn content by of EAS were investigated: concentration of heteroatom, reactive anodic species, and timing.

Preparations for a synthesis of tin-rich Sn-MFI controlled by different concentration profiles were realized as in the Example 1. The ICP-AES analysis was used for ex-situ concentration measurements.

The first obvious difference between EAS and a classic batch synthesis is the Sn concentration which can be tuned with the R _r . The crystallization behavior in EAS was studied and compared with classic batch crystallizations of Sn-MFI in the same conditions, off course with the difference of Sn addition at the start. In batch, a pure Si- MFI was studied, along with Si/Sn 55 and 110 from a SnC14 ^x 5H2O source, and here (as in literature (9-11)). Batch Si/Sn 55 is shown along with 2 EAS at different voltages applied for the full 3 days synthesis (Fig. IF). Due to the low synthesis temperature, a maximum yield of solids was limited to around 40% for both pure siliceous MFI and Sn versions. The kinetics of Sn-MFI (and most zeolites) crystallization clearly shows three regions, corresponding to nucleation, growth, and maturation. The highest slope on such S-shaped crystallization curve is the growth phase, where the uptake of silica and, in this case also tin, has its maximum rate (Fig. IF). All three show a similar S-curve, but the starting moment of their crystallization, correlated with the end of the nucleation stage, appears at a different time point. Again, this happens because nucleation time is very dependent on the amount of tin in a synthesis liquor (10-12). EAS here off course offers an exceptional case, as the concentration of tin starts from zero and is never constant as the Vpp-controlled R _r is applied. Based on these crystallization curves (i.e. the first derivative of the yield), the Sn-content of the resulting solid, average R _r values for a given Vpp and the water added in a synthesis, Sn-concentration profiles could be calculated (Fig. 1G). The batch synthesis (R _r = 0) has a relatively high starting value, and shows a drop caused by the rapid growth phase (see corresponding Fig. IE), where tin incorporation has the steepest slope. Contrarily, both EAS profiles increase from 0 with a slope that correlates with the tin release rate (dashed line). This slope is interrupted with a drop due to Sn-uptake similar as for the batch profile, but the drop is large, and the increase resumes after. Crucially, while the Sn-concentration in EAS is kept lower than in the batch case throughout, the zeolites recovered from EAS have a much higher Sn content (Si/Sn 96 and 32 respectively for 0.8 and 1.3 V _pp ) than the batch synthesis (Si/Sn 281, Fig. 2A; CD3CN FT-IR - Fig. 2B). This leads to conclude that 1) EAS offers access to materials richer in heteroatoms than classic synthesis (here: up to a 10-fold) - in batch at 90 °C, from 10 attempts, the Si/Sn was never lower than 281; 2) less soluble Sn is wasted and so the Sn efficiency (incorporated over total soluble tin) is 7 times higher for EAS; and 3) there is less hindrance for the nucleation (in low concentration) rendering it a faster process.

Example 5 Ex-situ preparation of anodically released tin precursors for Sn-MFI zeolite synthesis For a synthesis of a tin-containing MFI zeolite using an anodic metal oxidation technic, but with release ex-situ, a small excess of a pure-siliceous gel was prepared by the following method. In a typical synthesis, 15.806 g of TEOS were mixed in a beaker with 9.638 g of TPAOH and 7.869 g of water. The mixture was stirred until the final batch composition was reached: Si:0.25TPAOH: 10.0H20. Meanwhile, in a separate beaker, the same amount of TPAOH and H2O were mixed together and kept under stirring. Then, two (in most cases identical) tin metal plates with a fixed surface area of 13.4 cm ² were washed in acetone, dried, weight, attached to the pair of terminals, and immersed in the diluted OSDA solution. The electricity was turned on simultaneously (1.5Vpp, 50 pHz, sine waveform) for 18 hours for ex-situe released Sn. After that, amount of dissolved tin was established by a weight loss, and the final tin concentration was tuned by addition of TPAOH/H2O mixture. Finally, two solutions containing sources of silica and tin were combined together. For a general experiment, 15 g of the formed liquid gel with the batch composition of Si: 125Sn ^-1 :0.5TPAOH:20.0H20 were placed into a 23 ml Teflon-lined stainless steel autoclave, and closed and put in a static air oven. The remaining procedures after were performed as described in the Example 1 These experiments study a second factor which could be unique to EAS, i.e. the nature of in-situ released Sn-species, which are potentially different from hydrolyzed classic Sn precursors. Precursors for metal incorporation (e.g. often Sn halides) can sometimes play key roles in the synthesis outcome (73, 14). The rapid formation of a crystalline phase with a high Sn content exclusive to EAS hints to the formation of highly active species from the metal electrode surface by anodic oxidation. Therefore, next to comparing EAS and classic syntheses, batch experiments were run with either tin chloride and pre-released (ex-situ) anodically oxidized metallic tin. Both were dissolved into the organic structure directing agent solution before mixing with the silica source. The composition for both synthesis mixtures was estimated at Si/Sn 125, but neither led to a significant amount of incorporated tin, resulting in Si/Sn ratio 540 and 370 for the tin salt and anodic released Sn, respectively. These Si/Sn ratios pale in comparison to in-situ anodic metal oxidation, which either is explained by the mentioned need to keep the concentration low, or, by the short lived nature of anodically released more active species. Yet, ex-situ release anodic oxidized Sn still leads to heteroatom zeolites. Classic species originating from the basic hydrolysis of ionic salts (e.g. from tetra-halides) should be of the Sn(0H)4+ _p ^p " kind (7), whereas according to the Pourbaix diagram at the measured pH of 12.3, EAS species could be hydrated Sn(OH)e ² ' or Sn(0H)3- types, depending on the voltage.

Example 6 Time-controlled metal release for tin incorporation in MFI zeolite

Preparations for a synthesis of Sn-MFI with timed release control were realized as in the Example 1 with following changes: zeolite crystallization was hold for 72 hours, whilst electricity was applied after 16 hours since the moment of crystallization start and exclusively for the period of 8 hours (due to a high release rate).

Now that the role of Sn-concentration on the synthesis and the control of voltage-bias over anodic release are clear, the logical next step is timing the release in accordance with the S-shaped curve. A fast and reliable synthesis of Sn-MFI with a high metal loading could require a rapid passing of the nucleation phase, which is clearly found for pure silica systems. Sn impedes fast nucleation even though most of it stays in the liquor after crystallization in batch. In contrast, EAS allows to time its release by the push of a button right after nucleation, and at a desired rate, without having to disturb the crystallization irreversibly by cooling it down and adding a bolus of Sn. As such, a tuned EAS procedure was performed with anodic oxidation of tin only for 8 hours at 2 or 4 Vpp respectively, starting only after the first 16 hours of synthesis, the latter period corresponding to the induction of a pure Si-MFI. This yielded two zeolites with Si/Sn ratios of 77 and 45, respectively. This strategy not only allows to save time and obtain Sn-rich zeolite, it also manages to increase the tin efficiency, e.g. from 5% in batch up to 58% for timed EAS with 2 Vpp.

Example 7 Direct Current (DC) control of tin incorporation in MFI zeolite

Preparations for a synthesis of Sn-MFI with DC control were realized as in the Example 6 with following changes: variable voltage bias with a constant running current in the range from 2 to 35 mA, DC waveform.

Moreover, attempts were made to measure the Faradaic efficiency of the electrochemical reaction. For this, a constant direct current supply was connected which allows a variable voltage bias. While this is feasible and allowed to estimate Faradaic efficiencies in the range of 57 - 85 %, using constant current as a mode for EAS, is less straightforward as a mode to control R _r (Fig. ID and IE): trends were preserved). These numbers of Faradaic efficiency are obtained from a high voltage applied for generating a current threshold value, which can cause a set of electrochemical side-reactions such as water splitting and likely OSDA oxidation (darker color of solution after synthesis). In contrast to electrochemical production processes for organics (e.g. CO2 reduction (75), NH3 synthesis (76)), achieving high (or higher) Faradaic efficiencies is quite irrelevant here in the context of inorganic material synthesis. The consumed EAS electrical energy is few compared to the power needed for heating (e.g. a factor of 12 for 5 V _pp during 8 h in a 3 day synthesis) and the cost of synthesis ingredients such as organic structure directing agents and pure silica sources. Moreover, zeolite catalysts can be considered a ‘performance chemical’ as they have huge leverage effect (2 orders of magnitude) on the processes (e.g. organics productions) and markets they serve(77, 7S).

Example 8 Sine waveform control of zinc incorporation in MFI zeolite

The unique crystallization of siliceous MFI zeolites coupled with anodic oxidation has unveiled root causes to the behavior of Sn-containing synthesis mixtures. While stannosilicates are arguably the most valuable type of siliceous zeotypes and MFI is a topology with top relevance (7S), the value of the EAS should be broadened to other metals and frameworks. The generic nature of controlled anodic metal oxidation leading to metal incorporation in a zeolite framework was proven by the successful synthesis of single metal zeotypes of Zn- and Al-MFI, a mixed Sn,Zn-MFI, as well as Sn-BEA and Sn-, Ti-CHA zeolites with an extremely high tin loadings, and Sn-APO-5 aluminophosphate with AFI structure. For all stannosilicates, the Sn content achieved is the highest recorded to date in bottom up hydrothermal synthesis.

Preparations for a synthesis of Zn-MFI with controlled zinc incorporation were realized as in the Example 1 with following changes: electrode couple material - zinc, crystallization regime was completed in both 90 and 160 °C temperatures.

Based on well-known Zn-MFI syntheses in batch (79, 20) and similarities in the electrochemical dissolution of zinc and tin, the Sn-MFI EAS procedure was performed with a 0.8 Vpp sine with zinc electrodes. While the R _r of Zn is higher than that of Sn, a Zn-zeolite can also be richer in metal content due to the easier incorporation of Zn into zeolite structures. Counter to that, zinc in hydroxide media tends to form oxide/hydroxide precipitates, complicating the bulk elemental analysis of a zeolite material, especially when distinguishing them from framework zinc. The key advantage of EAS over batch is a low metal concentration profile during crystallization. This and a constant supply can allow the metal to remain in a favourable state for zeolitic incorporation. Such difference was unveiled by TEM-EDX for both samples synthesized at 90 °C and higher temperatures. In contrast with the EAS sample, a closer look at nano-crystals after batch synthesis at 90 °C demonstrates the presence of a second zinc-rich impure phase, whereas the EAS crystals have a single phase with nicely dispersed Zn (Fig. 2E). A range of Zn- MFI syntheses (5 EAS, 10 controls) and their analyses by various techniques such as ionexchange capacity (27) showed benefits for EAS synthesis. The case for Zn by EAS entails targeting a better framework integration while avoiding bulk Zinc oxide formation

Example 9 Time-controlled metal release for zinc incorporation in MFI zeolite

Preparations for a synthesis of Zn-MFI with timed release control were realized as in the Example 6 with following changes: electrode couple material - zinc, 5 Vpp.

Example 10 Simultaneous mixed metal release for heteroatom incorporation in MFI zeolite

Preparations for a synthesis of Zn,Sn-MFI with mixed metal release were realized as in the Example 1 with following changes: electrode material - zinc and tin (immersed surface of each electrode equals 6.7 cm ² ).

A synthesis of mixed Zn/Sn-containing MFI was conducted by EAS in AC conditions. For that, two different metal electrodes were placed in the reactor, and a small voltage of 1 Vpp (50 pHz) was applied for the 3 days. The resulting material had Si/Sn and Si/Zn ratios of 107 and 37, respectively. This is the first documented mixed Sn, Zn-MFI hydrothermal synthesis and it showcases the easy and broad applicability of EAS and how it offers access to novel advantageous combinations, and thus potentially revolutionary materials for Lewis acidic catalysis.

Example 11 Time-controlled metal release for aluminium incorporation in MFI zeolite

Preparations for a synthesis of Al-MFI with controlled aluminium incorporation were realized as in the Example 9 with following changes: electrode couple material - aluminium, electricity was turned on after first 24 hours of the experiment for the period of 24 hours, exclusively.

A successful synthesis of Al-MFI was completed by anodic oxidation of aluminum electrodes triggered on the second day of synthesis. Apparently, in hydroxide media without voltage applied, metallic aluminum is slightly dissolved, resulting in a final Si/Al ratio of 470. EAS-assisted, the aluminum content in the product zeolite was three times higher (Si/Al 140). The same threefold increase of Bronsted acid sites density (3.1 vs 10.9 pmol/g) was measured by Pyridine-FTIR (Fig. 2D) (22). While EAS can work for aluminum the release of ions from an aluminum electrode surface seems few as it is likely passivated by an oxide layer. Likely, the main amount of dissolved aluminum originated from EAS on the non-submerged part of the electrodes where water condensation took place and anodic oxidation and Al-release could occur due to the pH value being close to neutral. Further trials with Al-EAS in more neutral synthesis mixtures are possible.

Example 12 Sine waveform control of iron incorporation in MFI zeolite

Preparations for a synthesis of Fe-MFI with controlled iron incorporation were realized as in the Example 1 with following changes: electrode couple material - iron, which was exposed to a series of 30 minutes acid washings in 10 wt. % solutions consist of consequent HC1 - HNO3 - HC1 treatments prior an experiment, lOVpp, crystallization was conducted at 80 °C for 4 days in the EAS reactor, and then the resulting mixture was subjected for the secondarily crystallization at 160 °C for 2 days in a classic batch reactor. The EAS of iron-containing MFI zeolite was eventually performed by a complex treatment: two temperatures regime combined with in-situ anodic oxidation. Firstly, the EAS with 10 Vpp was performed at 80 °C for 4 days, a low temperature to slow down iron oxide formation after metal release into a hydroxide-rich solution. Secondly, the synthesis was stopped, and the reactor was opened; resulted products were stirred and equally divided into two parts: both phases of the first half were subjected to ICP-AES analysis (Measured Si/Fe of solid 75 and liquid 230), and the second half was put in a Teflon-lined stainless steel autoclave for a further crystallization at 160 °C for 2 days. Thirdly, the final solid product of the secondary crystallization was analyzed with the ICP-AES technic (Measured Si/Fe 160). A UV-vis-NIR study performed on the latter as-made samples shows a vague noisy signal for the direct EAS sample and a firm number of iron-incorporated bands for the second sample, proving modest success for Fe-containing MFI in the first case, and a good proof in the second example.

Example 13 Sine waveform control of tin incorporation in Si-BEA zeolite

For a synthesis of a tin-containing BEA zeolite using an anodic metal oxidation technic, a small excess of a pure-siliceous gel was prepared by the following method. In a typical synthesis, 12.550 g of TEOS were mixed in a beaker with 32.871 g of 4,4’- trimethylenebis(N-methyl, N-benzylpiperidinium)hydroxide (later referred as TMP(OH)2 ) and 2.455 g of water. The mixture was stirred until the final batch composition was reached: Si:0.3TMP(OH)2:25.0H2O. For a general experiment, 34 g of the formed liquid gel were placed into a 50 ml Teflon-lined custom-made stainless steel autoclave. Before an experiment, two (in most cases identical) tin metal plates with a fixed surface area of 13.4 cm ² were washed in acetone, dried, weight, and attached to the internal pair of nuts connectors. Afterward, an autoclave was closed and put into a heating mantel at room temperature. In the end, the pair of terminals were attached to the wire connectors on the top part of the custom-made reactor. The synthesis starting time was counted from 60 °C indicated on the controlling thermocouple. Voltage, frequency, and a waveform, the crucial parameters of an EAS, were set before the start of an experiment on all electric signal generators with the following characteristics: 1.0 Vpp, 50 pHz, sine waveform. The electricity was turned on after first 48 hours of the experiment for the period of 24 hours, exclusively. In total, crystallization has been conducted at 140 °C for 96 hours. Extraction of the solid product and its treatment was conducted as described in the Example 1.

The classic way of making Sn-BEA is through the mineralization of a gel with fluoride ions (23) while more recent strategies have been reported for Sn incorporation via postsynthetic treatments (24, 25). Surprisingly, there is only one procedure for the crystallization of siliceous BEA in hydroxide media (26, 27). Routes to Sn-containing BEA zeolites with low framework Si/Sn ratios, made in hydroxide media (opposed to hazardous HF media) are therefore highly desirable. Here, we show Sn-BEA samples with outstanding loadings of tin using EAS with a particular timing of the metal release. PXRD patterns show the progress of BEA crystallization at different temperatures in batch, with and without Sn using TMP(0H)2. With Sn, less intense reflections on the PXRD are easily noticed, which is induced by an affected nucleation stage (2S). While at 100 °C, this recipe allows for a pure siliceous BEA in about 3 days, with SnCE addition (and even at 140 °C), no crystallinity is observed, not even after 5 days. Using EAS at 140 °C, an experiment was designed that overcame the obvious crystallization barrier: anodic oxidation was timed to release Sn only during the second or third (out of four) day of the synthesis. As a result, zeolites with a record low for hydrothermal synthesis Si/Sn ratio of 25 and 14 (Fig. 3A) was formed in a much shorter time than the batch Sn-BEA synthesis from classic Sn salt precursors, where a Si/Sn ratio of 160 was evidenced after 20 days of crystallization. Additional attention should be given here to the metallic tin precursor since higher temperature and aggressive media stimulate electrode dissolution, which, eventually, leads to the formation of Sn-rich BEA zeolite (only in EAS reactor). Both EAS and batch zeolites were investigated with FTIR spectroscopy using CD3CN as a probe molecule to study the tin positioning in the framework (Fig. 3B) (29). Moreover, the Sn-acid site density was calculated, supporting high framework tin incorporations, the ‘ SnCE/framework tin’ ratio is generally lower (= better heteroatom incorporation) for zeolites made via EAS route.

Example 14 Sine waveform control of tin incorporation in Al-BEA zeolite

For an incorporation of tin in Al-containing BEA zeolite, an anodic metal oxidation technic was performed. For that, a small excess of an aluminium-containing (classic for zeolite synthesis) gel was prepared by the following method. In a typical synthesis, 37.400 g of TEOS were mixed in a beaker with 41.551 g of tetraethyl ammonium hydroxide (TEAOH) and 8.565 g of water. The mixture was stirred until all ethanol (product of hydrolysis, about 33.083 g) was evaporated, then 0.588 g of sodium aluminate were added, and the mixture was further homogenised for an additional hour. The final batch composition was reached as: Si:25AF ¹ :0.54TEAOH: 11.0H2O. For a general experiment, 34 g of the formed liquid gel were placed into a 50 ml Teflon-lined custom-made stainless steel autoclave. Before an experiment, two tin metal plates with a fixed surface area of 13.4 cm ² were washed in acetone, dried, weight, and attached to the internal pair of nuts connectors. Afterward, an autoclave was closed and put into a heating mantel at room temperature. In the end, the pair of terminals were attached to the wire connectors on the top part of the custom-made reactor. The synthesis starting time was counted from 60 °C indicated on the controlling thermocouple. Voltage, frequency, and a waveform, the crucial parameters of an EAS, were set before the start of an experiment on all electric signal generators with the following characteristics: 2.0 Vpp, 1 pHz, sine waveform. The electricity was turned on simultaneously with the start of the experiment. In total, crystallization has been conducted at 140 °C for 120 hours. Extraction of the solid product and its treatment was conducted as described in the Example 1.

A regular synthesis of Al-containing zeolite with BEA framework shows close to 100% uptake of aluminium, therefore, during the Electro-Assisted Synthesis procedure with the starting batch Si/Al ratio of 25, resulted in the material final Si/Al 27. Additionally, since the dissolution of tin was performed during this experiment, the final zeolite had the second metal also successfully incorporated in the framework. Due to the complications appeared during the HF-prepared dissolution/destruction ICP AES analysis method, the precise content of tin was hard to establish, thus an approximate Si/Sn of the final material was found to be around 96 ± 13. Moreover, the incorporation of tin was proven by UV- vis-NIR spectroscopy. Using deconvolution of the spectrum, characteristic bands of tetrahedral and octahedral tin were detected (Fig. 3i).

Example 15 Square waveform control of tin incorporation in CHA zeolite For a synthesis of a tin-containing CHA zeolite using an anodic metal oxidation technic, a small excess of a pure-siliceous gel was prepared by the following method. In a typical synthesis, 8.860 g of ammonium fluorosilicate were mixed in a beaker with 26.258 g of N,N,N-trimethyl-l-adamantanammonium hydroxide (later referred as TMAdamOH) and 5.850 g of water. After 30 minutes of vigorous stirring, 11.956 g of ethylenediamine (later referred as EDA) were added, causing exothermic heating of the mixture. At last, after another 60 minutes, 0.149 g of Si-CHA seeds synthesized in advance were added, then the mixture was stirred for another 3 hours prior to the synthesis. The mixture was stirred until the final batch composition was reached: Si:0.5TMAdamOH:4.0EDA:6.0F' 3O.OH2O. For a general experiment, 34 g of the formed liquid gel were placed into a 50 ml Teflon-lined custom-made stainless steel autoclave. Before an experiment, two (in most cases identical) tin metal plates with a fixed surface area of 13.4 cm ² were washed in acetone, dried, weight, and attached to the internal pair of nuts connectors. Afterward, an autoclave was closed and put into a heating mantel at room temperature. In the end, the pair of terminals were attached to the wire connectors on the top part of the custom- made reactor. The synthesis starting time was counted from 60 °C indicated on the controlling thermocouple. Voltage, frequency, and a waveform, the crucial parameters of an EAS, were set before the start of an experiment on all electric signal generators with the following characteristics: 2.0 Vpp, 25 pHz, square waveform. The electricity was turned on after first 24 hours of the experiment for the release burst during 2 hours, exclusively. In total, crystallization has been conducted at 120 °C for 72 hours. Extraction of the solid product and its treatment was conducted as described in the Example 1.

The CHA zeolite has an interesting topology of large cages confined by small pores. Yet, there is only one synthesis route known to incorporate Sn, via a dry-gel conversion method at 160 °C for 2 days (30). Using EAS, we attained Sn-CHA with few effort and a high tin loading at 120 °C within 3 days. Two EAS methods were tested, a burst of tin release dosed by 2 V _pp (square wave, 25pHz) for 2 hours only, either at the start of the first or the second day of synthesis, resulting in Si/Sn ratio of 57 and 68, respectively (Fig. 3C, FTIR CD3CN Fig. 3D). A similar experiment with a 2 hours burst of 4 V _pp at the start of the synthesis had rapid tin release (R _r =314 mol/(s*cm ² )x le-10), which resulted in excessive tin supply, leading to amorphous material with Si/Sn ratio 14. Moreover the EAS sample synthesized with delayed tin release (2 hours in the second day) resulted in the highest crystallinity in the Sn-CHA series, comparable to the Si-CHA batch synthesis and a high tin content (Si/Sn 68).

Example 16 Square waveform control of titanium incorporation in CHA zeolite

Preparations for a synthesis of Ti-CHA with controlled titanium incorporation were realized as in the Example 14 with following changes: electrode couple material - titanium.

An attempt at Ti-CHA was made, and with only one EAS experiment, a controversial result was achieved. The EAS was conducted in the best regime for Sn-CHA, resulting in a highly crystalline material with the Si/Ti ratio of 62 (Fig. 3E). a comparison sample, where titanium could come solely from thermochemical media dissolution, had a Si/Ti ratio of 21. Framework Ti incorporation was proven for both zeolites with UV- vis-NIR spectroscopy (Fig. 3F), but the EAS sample seemed to be closer to the tetrahedral Ti zone at 230 nm, commonly attributed to tetrahedral TiCU, while the batch sample’s band was in between 230 and 320 nm, the latter corresponding to octahedral TiOe units as in anatase (40). A hypothesis consists of electrode surface poisoning in EAS: since the square wave was applied for a time shorter than the frequency shift, the surface of only electrode was blocked with an oxide layer suppressing further (thermo- and electrochemical) dissolution, better dosing the Ti. A deeper investigation for titanium release is pending, but this example already evidences the EAS applicability and the apparatus to disrupt metal release in different, but interesting ways

Example 17 Sine and square waveform control of tin incorporation in Sn-APO-5

For a synthesis of a tin-containing aluminophosphates with AFI framework using an anodic metal oxidation technic, a small excess of a pure-aluminous gel was prepared by the following method. In a typical synthesis, 3.689 g of orthophosphoric acid were mixed in a beaker with 27.613 g of water. After 10 minutes of stirring, 2.266 g of aluminium oxide were added, and the system was left under vigorous stirring for 30 minutes. At the last step, 5.000 g of N-methyldi cyclohexylamine (later referred as DCMA) were added, and the system was left for 30 more minutes to reach a homogeneous gel. The mixture was stirred until the final batch composition was reached: A1:P:0.8DCMA:50.0H20. For a general experiment, 34 g of the formed liquid gel were placed into a 50 ml Teflon-lined custom-made stainless steel autoclave. Before an experiment, two (in most cases identical) tin metal plates with a fixed surface area of 13.4 cm ² were washed in acetone, dried, weight, and attached to the internal pair of nuts connectors. Afterward, an autoclave was closed and put into a heating mantel at room temperature. In the end, the pair of terminals were attached to the wire connectors on the top part of the custom-made reactor. The synthesis starting time was counted from 60 °C indicated on the controlling thermocouple. The electricity was turned on simultaneously. Voltage, frequency, and a waveform, the crucial parameters of an EAS, were set before the start of an experiment on all electric signal generators with the following characteristics: 1.0 - 2.0 Vpp, 50 pHz, sine or square waveform. Crystallization has been conducted at 160 °C for 24 hours. Extraction of the solid product and its treatment was conducted as described in the Example 1.

Broadening from silicates to substituted aluminophosphates, another class of microporous molecular sieves further widens the applicability of EAS. Sn-APO-5 (topology AFI), documented in the art, was reproduced with Sn-halide salts for benchmarking (37). A successful EAS was conducted at 160 °C in the 1-2 VPP range within 24 hours (PXRD - Fig. 3G), whereas a comparison sample with immersed electrodes showed only a slight thermal dissolution of the tin electrode surface in the acidic conditions (pH 5.1). The incorporation of tin in the final materials was proven with UV-vis-NIR spectroscopy, where the adsorption band at 200 nm suggests the presence of tetra-coordinated Sn in the framework (Fig. 3H) e.g. absent in a pure A1PO-5 and the tin tetrachloride precursor sample. Therefore, all EAS materials have tin in their framework, but the Al/Sn ratio is much lower for the EAS case 37-81 vs. 171 for the case with immersed electrodes. These attempt confirm the flexibility of EAS for synthetic purposes of metal-substituted materials in more neutral to slightly acidic media opposed to the basic pH cases above. And they demonstrate the applicability from siliceous zeolite hosts to other types of molecular sieve host compositions (A1,P).

Example 18 Catalytic tests of tin containing MFI and BEA zeolites Catalytic conversion of 1,3-dihydroxyacetone (DHA) in methanol to methyl lactate (ML) was performed under autogenous pressure in 10 mL thick- walled glass reactors placed in a preheated copper block at 80 °C. Typically, 0.1126 g of DHA, 80 mg of catalyst, 60 mg of naphthalene, and 5.0 mL of methanol were added to a test vial. The vessel was then heated and vigorously stirred for several hours, followed by quenching in an ice bath for sampling. The same amount of substances was used, while the high-temperature (>100 °C) reaction kinetic was measured in the closed SS reactor with a sampling valve. After the reaction, products were quantified through GC-FID analysis.

To showcase the now increased densities of Sn site in MFI and BEA, the conversion of the sugar 1,3-dihydroxyacetone to methyl lactate was performed, a reaction where tin oxides, in case a small amount is present, are inactive (32). The controls for Sn-MFI are a low and high temperature batch sample (higher Sn incorporation at 160 °C), whereas for Sn-BEA, the classic fluoride-assisted Sn-BEA was synthesized), respectively. Figure 4A shows that the EAS-MFI attains the best yield and certainly much better in contrast with the control made at 90 °C (the same temperature used in EAS). For Sn-BEA (Fig. 4B), our EAS-made zeolite demonstrates a 3 -fold increased productivity (13 molMLA.kgcat^.h' ¹ ) vs the well-known fluoride Sn-BEA (32). Using kinetic analyses and an Arrhenius plot over a wide temperature range (Fig. 4C), we evidence that the apparent activation energies are very similar at 64 kJ/mol for both Sn-BEA zeolites, and akin to literature (33, 34).

An entirely new mode for making heteroatom-containing zeolites is presented using a novel flexible electrochemical reactor. Performing anodic oxidation finely controlled by a voltage bias on immersed electrodes, the timing and concentration of heteroatom precursors can be tuned in-situ during the zeolite crystallization - opposed to only by means of a starting concentration in classic batch synthesis. This electro-assisted synthesis mode allows to produce stannosilicates with record Sn incorporation by keeping the concentration of Sn low and tuning the timing of its release to avoid nucleation delays. The concept is generic as the synthesis of Sn-MFI (Si/Sn 32), Sn-BEA (Si/Sn 14) and the hard-to realize Sn-CHA (Si/Sn 62) and Sn-APO-5 were easily made in short synthesis times in hydroxide (and acidic) media. These Lewis acidic materials are renowned catalysts for a range of reactions and increasing their acid-site density is of key importance to their productivity. To a degree, the concept is also generic to other metals, as Fe, Al, Ti and Zn release in presence of zeolite growth with framework incorporation was documented, as well as mixed metal zeotypes (Zn/Sn). Combining zeolite synthesis with in-situ anodic oxidation of metal precursors now opens up a vast range of possibilities for creating advanced materials suitable for various catalytic and other zeotype applications. For one, it now allows to investigate nearly all siliceous synthesis that have been reported and opens up the prospect of incorporating Sn in their framework. This is a new reactor-based and thus external handle for zeolite synthesis, opposed to the classic so-called internal ‘changing of ingredients’ based handles. The road to endless new zeotypes and heteroatom content variations has been opened with this invention.

Particular and preferred aspects of the invention are set out in the accompanying independent and dependent claims. Features from the dependent claims may be combined with features of the independent claims and with features of other dependent claims as appropriate and not merely as explicitly set out in the claims.

Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this

Drawing Description

BRIEF DESCRIPTION OF THE DRAWINGS AND TABLES

The present invention will become more fully understood from the detailed description given herein below and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein:

FIG. 1 shows a (A) De-novo reactor for EAS and main modes of metal releaseincorporation control with its technical elements ® a release valve, ® a high P release valve, ® a thermocouple ® a pressure gauge ® copper connectors ® crocodile terminals ® electrode plates ® stirring bar ® teflon bar ® reactor cover. (B) Correlation between the applied voltage difference in AC mode for sine (dots) and square (triangles) waveforms and the release rate (Rr) of tin; (C) the same R _r versus the final Sn-MFIs’ Si/Sn ratio. The black cross on both figures shows the limits of precise Sn control via EAS as fewer firm results were obtained at higher Vpp. (D) Correlation between applied current in DC mode in a constant current regime and R _r . Due to high values of R _r , a current was applied for 8 h after the first 16 h of synthesis. (E) The same R _r from D plotted against the final Sn-MFIs’ Si/Sn ratio obtained in DC mode. (F) Sn-MFI crystallization curves in batch (Si/Sn 74) and EAS conditions; (G) Ex-situ measured tin concentration profiles for the two EAS, and batch synthesis from F. Blue-banded areas on the EAS profiles show the experimental error measured by solid and liquid phases ICP-AES analysis. Dashed lines show a theoretical Sn concentration based on average R _r values.

FIG. 2 shows generic nature of EAS for metallosilicate MFI zeotypes and their characterization. (A) PXRD patterns of Sn-, Al- and Zn-MFI zeolites showing no structural, metal, or oxide impurities. CD3CN FT-IR on Sn-MFIs synthesized in (B) the batch conditions (starting Si/Sn 74) and (C) via the EAS route with 1.5 Vpp; (D) Pyridine FT-IR on Al -MFIs synthesized in the electro-reactor with and without applied voltage. (E) TEM EDX pictures of Zn-MFIs synthesized via batch (top) and EAS (bottom) at 90°C. The different intensity is caused by the 2x higher zinc loading of the batch material. FIG. 3 shows generic nature of EAS for different topologies and their characterization. PXRD patterns of zeotypes synthesized in the electro-reactor: (A) Sn-BEA (48h-24hE- 24h), (C) Sn-CHA and (E) Ti-CHA (24h-2hE-46h), (G) Sn-APO-5 (1 VPP, square wave). CD3CN FT-IR spectra of EAS zeolites: (B) Sn-BEA (48h-24hE-24h) and (D) Sn-CHA (24h-2hE-46h). (F) UV-vis-NIR spectra of as-made (Ti-)CHA zeolites crystallized in batch and EAS conditions, and TiCE. (H) UV-vis-NIR spectra of as-made (Sn-)APO-5 crystallized in batch and EAS conditions, (i) UV-vis-NIR spectra of as-made Sn-Al-BEA zeolite crystallized in EAS conditions with deconvolution of tetrahedral (framework) and hexahedral (extra-framework = oxide) tin bands.

FIG. 4 shows catalytic performance of Sn-containing zeolites for triose-to-lactates. Yield of ML over (A) Sn-MFI zeolites at 80 °C; and (B) Sn-BEA zeolites at 60 and 80 °C. (C) Arrhenius plot for Sn-BEA catalysts.

Table 1 provides results on samples synthesized with anodic oxidation according to given examples. In table lb Resulted Si/Me ratio comes from Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES) analyses were conducted on PerkinElmer Optima 3300 DV with signals for Si, Al, Sn, Fe, Zn, Ti, P at 251.6, 380.2, 189.9, 238.2, 213.9, 334.9, and 213.6 nm, respectively. SBET, and Microporous volume come from Nitrogen adsorption isotherms in the relative pressure range of 0-1 bar measured on a Tristar II 3020 instrument. All the samples were dried at 300 °C for 6 h prior to analysis. The textural properties of all samples were then obtained from the adsorption isotherms. The Brunauer-Emmett-Teller (BET) specific surface area was calculated according to the Rouquerol method. The micropore volume (Vmic) was deducted from the t-Plot method.

Electrod Electro Time of

Example Frame Temp. Synthesis e de Voltage, Frequency, applied work °C duration, h composi area, pHz electric! tion cm2 ty, h

1 MFI 90 72 Sn 13.4 1.0 50 72

2 MFI 90 72 Sn 6.7 0.8 50 72

2 MFI 90 72 Sn 13.4 0.8 50 72

2 MFI 90 72 Sn 30.8 1.0 50 72

3 MFI 90 72 Sn 13.4 0.7 50 72

4 MFI 90 72 Sn 13.4 1.3 50 72

5 MFI 90 72 Sn 13.4 1.5 50 18, prior the exp

6 MFI 90 72 Sn 13.4 2.0 50 16-8E-48

7 MFI 90 72 Sn 13.4 DC, 8 mA 16-8E-48

7 MFI 90 72 Sn 13.4 DC, 25 mA 16-8E-48

7 MFI 90 72 Sn 13.4 DC, 35 mA 16-8E-48

8 MFI 90 72 Zn 13.4 0.8 50 72

8 MFI 160 72 Zn 13.4 0.8 50 72

9 MFI 90 72 Zn 13.4 5.0 50 16-8E-48 36

10 MFI 90 1.0 50 36

11 MFI 90 72 Al 13.4 5.0 50 24-24E-24

11 MFI 80 96 Fe 13.4 10.0 50 96

12 MFI 160 48 Fe Sc* Sc* Sc* Sc*

13 BEA 140 96 Sn 13.4 1.0 50 48-24E-24

14 CHA 120 72 Sn 13.4 2.0 25 24-2E-46

15 CHA 120 72 Ti 13.4 2.0 25 24-2E-46

16 AFI 160 24 Sn 13.4 1.0 50 24

16 AFI 160 24 Sn 13.4 1.0 50 24

Table la

*Sc = Secondary crystallization Synthesis

Example Frame Temperature Electrode Resulted SBET, Microporous duration, Waveform

# work °C composition Si/Me ratio m ² /g volume, cm ³ /g h

1 MFI 90 72 Sn Sine 54 638 0.12

2 MFI 90 72 Sn Sine 171 524 0.16

2 MFI 90 72 Sn Sine 96 539 0.13

2 MFI 90 72 Sn Sine 42 589 0.12

3 MFI 90 72 Sn Square 173 542 0.16

4 MFI 90 72 Sn Sine 32 609 0.13

5 MFI 90 72 Sn Sine 590 508 0.13

6 MFI 90 72 Sn Sine 77 538 0.14

7 MFI 90 72 Sn - 325 547 0.14

7 MFI 90 72 Sn - 72 528 0.14

7 MFI 90 72 Sn - 36 520 0.16

8 MFI 90 72 Zn Sine 47 580 0.12

8 MFI 160 72 Zn Sine 21 401 0.11

9 MFI 90 72 Zn Sine 44 541 0.12

Zn 37

10 MFI 90 72 Sine 564 0.11

Sn 107

11 MFI 90 72 Al Sine 143 534 0.16

11 MFI 80 96 Fe Sine 75 554 0.14

12 MFI 160 48 Fe 162 497 0.12

13 BEA 140 96 Sn Sine 14 552 0.12

14 BEA 140 120 Sn Sine 96 534 0.11

15 CHA 120 72 Sn Square 68 642 0.24

16 CHA 120 72 Ti Square 62 639 0.21

17 AFI 160 24 Sn Sine 37 223 0.06

17 AFI 160 24 Sn Square 81 279 0.07

Table lb