THIS INVENTION relates to a process for treating a mixed olefin and paraffin feedstock.

According to the invention, there is provided a process for treating a mixed olefin and paraffin feedstock, which process comprises reacting, in a reaction zone and in a liquid phase, a mixed olefin and paraffin feedstock comprising at least one olefin and at least one paraffin, with a peroxidation component, thereto to form, from the olefin, an olefin oxide and/or a glycol and/or a glycol alkyl ether, while the paraffin remains in substantially unreacted form.

The total number of carbon atoms, ie the total carbon number, of the olefin as well as the paraffin preferably does not exceed 20. Thus, the olefin may be a C2-C2o olefin, while the paraffin or saturated hydrocarbon may be a C2-C2o paraffin.

The olefin will thus have at least one position of unsaturation along its carbon backbone, where peroxidation takes place.

The C2-C2o olefin may have the general formula R1R2C=CR3R4............................. (1) wherein Rl, R2, R3 and R4 can be the same or different, and are selected from the group consisting in hydrogen,

halogen, nitro, hydroxyl, cyano, amino, carboxy, cyclic hydrocarbon, phenyl, and C1-Cl8 alkyl.

The C2-C2o paraffin may have the general formula R1R2C-CR3R4...................... (2) wherein R1, R2, R3 and R4 are, as also hereinbefore defined, the same or different, and are selected from the group consisting in hydrogen, halogen, nitro, hydroxyl, cyano, amino, carboxy, cyclic hydrocarbon, phenyl, and C1-Cl8 alkyl.

The olefin and paraffin may be of the same carbon length, or may be of different carbon lengths. However, they will normally be close-boiling, ie boil at about the same temperature. For example, when the olefin is propene which boils at-47,7°C, the paraffin may be propane, which boils at-42,1°C.

The feedstock may, in particular, be a close-boiling Fischer-Tropsch derived or refinery mixture of said at least one olefin and said at least one paraffin. The mixture may naturally comprise a plurality of the olefins and/or a plurality of the paraffins.

By'Fischer-Tropsch derived'is meant a mixture, component or fraction obtained by subjecting a synthesis gas comprising carbon monoxide and hydrogen to Fischer-Tropsch reaction conditions in the presence of an iron-based Fischer-Tropsch catalyst, a cobalt based Fischer-Tropsch catalyst, an iron/cobalt based Fischer-Tropsch catalyst, or a mixture of two or more of such Fischer-Tropsch catalysts, with the resultant Fischer-Tropsch reaction products being worked up to obtain the mixture, component or fraction in question.

Examples of close-boiling Fischer-Tropsch derived or refinery mixtures which can be used as the feedstock

include propane and propylene mixtures, butane and 1-butene mixtures, pentane and 1-pentene mixtures, hexane and 1- hexene mixtures, heptane and 1-heptene mixtures, and octane and 1-octene mixtures, as well as mixtures of branched, hydrogen, halogen, nitro, hydroxyl, cyano, amino, carboxy, cyclic hydrocarbon, aromatic, or any substituted olefins and paraffins of the same and/or different carbon lengths.

While the carbon number of the olefin (s) and the paraffin (s) in the feedstock will generally be the same, this need not necessarily be so. Thus, for example, the feedstock may comprise a mixture of 3-methyl-1-pentene, 4- methyl-1-pentene and pentane.

The molar or mass proportion of olefin (s) to paraffin (s) in the feedstock can vary widely, but may be in the range of 100: 1 to 1: 100, typically in the range 10: 1 to 1: 10, eg about 1: 1. Likewise, when the feedstock comprises more than one olefin, the molar proportions of the olefins can vary widely, and the same applies when the feedstock comprises more than one paraffin.

The peroxidation component may comprise hydrogen peroxide (which is commercially available as a 30% solution in water); an organic peroxide such as tert-butyl hydroperoxide; an organic peracid such as peracetic acid; or the combination of an oxygen-containing gas, such as air, and an aldehyde, such as propionaldehyde or isobutylaldehyde.

The reaction may take place in the presence of a catalyst capable of promoting the reaction of the peroxidation component with the olefin (s). The catalyst, when present, may be a heterogeneous catalyst, and may comprise a titanium-containing synthetic zeolite such as titanium silicalite, titanium aluminosilicate or titanium ß-zeolite,

or any suitable heterogeneous metal-supported or oxide peroxidation catalyst known to those skilled in the art.

When the catalyst is present, the amount thereof that is used is not essential, but substantially sufficient catalyst should be used to accomplish the desired peroxidation reaction within as short a reaction time as is possible. The amount of catalyst used will thus depend on factors such as the reaction temperature, olefin reactivity, type and concentration of any solvent which is used in the reaction as set out hereunder, the peroxidation component concentration, the catalyst activity, and the nature of the reactor providing the reaction zone, ie a batch reactor or a continuous reactor. Thus, the process can be either a batch process or a continuous process.

Additionally, at least some of these parameters may be used to control the products derived from the reaction, ie whether mainly the olefin oxide, the glycol and/or glycol alkyl ether, or a mixture thereof are produced.

The catalyst may, in particular, be in particulate form.

The reaction may then be effected in a slurry phase wherein the particulate catalyst is maintained in suspension or admixture with the feedstock, eg by stirring. Instead, however, the particulate catalyst may be in the form of a fixed or static catalyst bed with the feedstock then being in contact with the catalyst bed, eg passing or circulating through the bed. The fixed or static catalyst bed may then contain also an inert particulate material such as sand, in admixture with the particulate catalyst. The Applicant has found that, by using such an admixture of the catalyst and sand in a continuous fixed bed process, the exothermic nature of the reaction is readily controlled, and a high selectivity of the reaction to the oxide is obtainable.

As stated hereinbefore, the reaction is effected in a liquid phase. The feedstock may thus be admixed with a liquid carrier capable of dissolving or dispersing the olefin (s), the paraffin (s) and the peroxidation component.

The carrier liquid may comprise water; an alcohol, especially a C1-Cl0 aliphatic alcohol such as methanol or ethanol; ketone, especially a C3-C1o ketone such as acetone; a nitrile, especially a C2-C10 nitrile such as acetonitrile; a chlorinated solvent, especially a highly chlorinated solvent such as dichloromethane; and mixtures of these carrier liquids or solvents. If the production of a specific glycol alkyl ether from the corresponding olefin in the Fischer-Tropsch or refinery mixture of olefin and paraffin is desired, then it is obvious that the correct alcohol must be selected for the peroxidation reaction.

The peroxidation reaction may be effected at a temperature between-20°C and 180°C, preferably between 0°C to 100°C, and more preferably between 20°C and 70°C. However, the reaction temperature will be influenced by the selectivity and product distribution required from the peroxidation reaction. Thus, if only, or primarily, an olefin oxide is required as the reaction product, a reaction temperature between 20°C and 70°C to 80°C will be used. However, if only, or primarily, glycol or the glycol alkyl ether is required as reaction product, then the reaction temperature will be controlled at between 70°C to 80°C and 180°C.

Generally, to obtain glycol and/or glycol alkyl ether as peroxidation reaction products, higher reaction temperatures (80°C to 180°C) and longer reaction or residence times (depending on the peroxidation component used), with the reaction time being matched to achieve minimal non-selective decomposition of the peroxidation source, are required. In addition, the appropriate carrier liquid or solvent, normally an alcohol, must be used, and the peroxidation component must be correctly selected.

Under the correct reaction conditions, especially the correct reaction temperatures as set out hereinbefore, the selective peroxidation of the olefin in the narrow-boiling Fischer-Tropsch or refinery mixture of olefin and paraffin within a reasonably short period of time with minimal non- selective decomposition of the peroxidation source can be accomplished. The optimum reaction temperature will be influenced by catalyst amount and activity, the olefin (s) concentration and reactivity, and the type of solvent employed.

Reaction times may typically be from 1 minute to 48 hours.

The longer the residence time inside the reactor the higher the selectivity towards the glycol or glycol alkyl ethers from the corresponding olefin (but depending also on the solvent used) in the Fischer-Tropsch or refinery mixture of olefin and paraffin. However, it has surprisingly been found that the paraffin (s) in the Fischer-Tropsch or refinery mixture of olefin (s) and paraffin (s) remain unaffected (unreacted) for the duration of the peroxidation reaction, irrespective of whether long or short residence times are used.

The reaction may be effected at atmospheric or elevated pressure, which, when used, is typically between 1 and 100 bar or atmospheres.

After completion of the reaction to the desired degree of selectivity and conversion, the olefin oxide and/or the glycol and/or glycol alkyl ether, and paraffin may be separated and recovered from the reaction mixture using any suitable technique such as fractional distillation, extractive distillation, or the like. After separating the catalyst from the reaction mixture, eg by filtration in the event of a slurry process being used, the catalyst can be re-used in subsequent peroxidations. Where the catalyst is employed in the form of a fixed bed reactor on a

continuous basis, it may be desirable periodically to regenerate the catalyst in order to maintain optimum activity and selectivity. Suitable regeneration techniques are, for example, calcination and solvent treatment.

The olefin oxides produced by the process can be used, for example, for production of, or in applications such as, glycol, glycol alkyl ethers, polyol, surfactants or detergents (tensides), antistatic-or corrosion-protection agents, additives to laundry detergents, lubricating oils, textiles and cosmetics.

The unreacted paraffins produced by the process can be used, for example, in chemical processes involving oxidation, oxychlorination, dehydrogenation, aromatization or the like.

The glycols produced by the process can be used, for example, for production of, or in applications such as, polyester resins, humectants, solvents, preservatives in food and pet food products, lubricants for machinery, in food wraps, antifreeze agents in machinery cooling water, emollients, softening agents, humectants in skin-care products and cosmetics, as carriers for livestock medicinal products, precursors of many polyether polyols used in the urethane foam, elastomers, adhesives, in the sealants industry, and cross-linking agents for insecticides.

The glycol alkyl ethers produced by the process can be used, for example, for production of, or in applications such as, solvents for formulations such as paints, inks and cleaning fluid applications, antiicing agents in jet fuel, as fluids for hydraulic systems, and as chemical intermediates for plasticizers and polymer applications.

The invention extends also to olefin oxides, glycols and glycol alkyl ethers, when produced by the process of the invention.

The invention will now be described in more detail with reference to the accompanying diagrammatic drawing, and with reference to the subsequent non-limiting examples.

In the drawing, reference numeral 10 generally indicates a process according to the invention for treating a mixed olefin and paraffin feedstock.

The process 10 includes a fixed catalyst bed reactor 12.

A catalyst addition line 14 leads into the reactor 12, as does a feedstock feed line 16. A peroxidation component feed line 18 also leads into the reactor 12, as does a carrier liquid or solvent feed line 20. In a process 10 employing a fixed catalyst bed reactor 12, the catalyst is normally regenerated in the reactor by means of solvent washes. However, if the regenerated catalyst requires calcination before re-use, then the total catalyst bed is removed from the reactor, regenerated, and reloaded into the reactor.

Thus, a spent catalyst withdrawal line 22 leads from the reactor 12 to a catalyst regeneration stage 24, with a regenerated catalyst recirculation line 26 leading from the regeneration stage 24 back to the line 14.

A withdrawal line 28 leads from the reactor 12 to a distillation stage 30, with an olefin product withdrawal line 32 as well as a paraffin withdrawal line 34 leading from the stage 30.

In use, a suitable catalyst such as a particulate titanium aluminosilicate catalyst is introduced into the reaction zone of the reactor 12 through the line 14. The

particulate catalyst is thus present as a fixed or static catalyst bed within the rector 12.

A Fischer-Tropsch derived mixed olefin and paraffin feedstock stream, such as a mixture of propylene and propane, is introduced into the reactor 12 along the flow line 16, simultaneously with a carrier liquid or solvent such as methanol along the flow line 20, and a peroxidation component, such as hydrogen peroxide, along the flow line 18.

The reactor 12 is typically maintained at about 40°C, with the propylene and hydrogen peroxide reacting to form propylene oxide which is withdrawn, together with unreacted propane, along the flow line 28. The reactor is typically maintained at a pressure of about 20 bar.

From time to time, as required, spent catalyst is withdrawn from the reactor 12 along the line 22, regenerated, eg through solvent treatment and calcination, in the regeneration stage 24, and fed back into the reactor 12 along the lines 26,14.

The product withdrawn along the flow line 28 is separated, in the distillation stage 30, into a propylene oxide component which is withdrawn along the flow line 32, and an unreacted paraffin component, which is withdrawn along the flow line 34.

EXAMPLE 1 10g of a titanium aluminosilicate catalyst in a mixture of 150m methanol, 35g of a 75/25 (m/m) mixture of liquid propylene and propane, and 50mE of hydrogen peroxide (30 weight percent solution in water) were introduced into a pressure reactor at 20 bar pressure. The mixture was heated to 40°C under stirring. A sample was withdrawn and analyzed. Unconverted hydrogen peroxide was determined by

iodometric titration, while unconverted propylene and unreacted propane in the propylene/propane mixture and the peroxidation product, propylene oxide, were determined using gas chromatography. With a hydrogen peroxide conversion of 97%, 95% of propylene oxide was formed, with reference to the propylene converted. The propylene oxide selectivity, with reference to the peroxidation products formed, was 93%. The propane in the mixture was unaffected, ie was unreacted.

EXAMPLE 2 <BR> 200mg of a titanium silicalite catalyst in a mixture of<BR> lOmQ methanol, 120 81 ouf a 50/50 (m/m) mixture of 1-hexene and hexane, and 50 ßl of hydrogen peroxide (30 weight percent solution in water) were introduced into a round- bottomed flask. The mixture was left at room temperature under stirring. A sample was withdrawn and analyzed Unconverted hydrogen peroxide was determined by iodometric titration, while unconverted 1-hexene and unreacted hexane in the 1-hexene/hexane mixture, and the peroxidation product, hexene oxide, were determined using gas chromatography. With a hydrogen peroxide conversion of 70%, 69% of hexene oxide was formed, with reference to the 1-hexene converted. The hexene oxide selectivity, with reference to the peroxidation products formed, was 95%.

The hexane in the mixture was unaffected.

EXAMPLE 3 15mye of chloroform, 4g of a 40/60 (m/m) mixture of 1- pentene and pentane, and 4mQ of peracetic acid (39 weight percent solution in acetic acid) were introduced into a round-bottomed flask. The mixture was left at room temperature under stirring. A sample was withdrawn and analyzed. Unconverted peracetic acid was determined by iodometric titration, while unconverted 1-pentene and unreacted pentane in the 1-pentene/pentane mixture, and the peroxidation product, pentene oxide, were determined using

gas chromatography. With a peracetic acid conversion of 96%, 93% of pentene oxide was formed, with reference to the 1-pentene converted. The pentene oxide selectivity, with reference to the peroxidation products formed, was 92%.

The pentane in the mixture was unaffected.

EXAMPLE 4 0,2g of a calcined silver oxide catalyst in a mixture of loomf of dichloromethane, 5,8g of iso-butylaldehyde and lOg of a 50/50 (m/m) mixture of 1-hexene and hexane were introduced into a pressure reactor. The mixture was heated to 60°C, and an air pressure of 30 bar applied while stirring vigorously. A sample was withdrawn and analyzed.

Unconverted 1-hexene and unreacted hexane in the 1- hexene/hexane mixture, the peroxidation product, hexene oxide, and the oxidation product, iso-butyric acid, were determined using gas chromatography. With a 1-hexene conversion of 9%, 98% of hexene oxide was formed, with reference to the 1-hexene converted. The hexene oxide selectivity, with reference to the oxidation products formed, was 99%. The hexane in the mixture was unaffected.

EXAMPLE 5 lOg of a titanium aluminosilicate catalyst in a mixture of 150m methanol, 35g of a 75/25 (m/m) mixture of liquid propylene and propane, and 50m of hydrogen peroxide (30 weight percent solution in water) were introduced into a pressure reactor at 20 bar pressure. The mixture was heated to 90°C under stirring. A sample was withdrawn and analyzed. Unconverted hydrogen peroxide was determined by iodometric titration, unconverted propylene and unreacted propane in the propylene/propane mixture and the peroxidation product, propylene oxide, were determined using gas chromatography. With a hydrogen peroxide conversion of 99%, 3% of propylene oxide, 46% of propylene glycol and 31% of propylene glycol methyl ethers were formed, with reference to the propylene converted. The

propylene oxide, propylene glycol and propylene glycol methyl ethers selectivity, with reference to the peroxidation products formed, were 97%. The propane in the mixture was unaffected.

EXAMPLE 6 15mQ of chloroform, 4g of a 20/20/60 (m/m) mixture of 3- methyl-1-pentene, 4-methyl-1-pentene and pentane, and 4mQ of peracetic acid (39 weight percent solution in acetic acid) were introduced into a round-bottomed flask. The mixture was left at room temperature under stirring. A sample was withdrawn and analyzed. Unconverted peracetic acid was determined by iodometric titration, while unconverted 3-methyl-1-pentene, 4-methyl-1-pentene and unreacted pentane in the 3-methyl-1-pentene/4-methyl-1- pentene/pentane mixture, and the peroxidation products, 3- methyl-1-pentene oxide and 4-methyl-1-pentene oxide, were determined using gas chromatography. With a peracetic acid conversion of 94%, 88% of 3-methyl-1-pentene oxide and 96% 4-methyl-1-pentene oxide were formed, with reference to the 3-methyl-1-pentene and 4-methyl-1-pentene converted. The combined 3-methyl-1-pentene oxide and 4-methyl-1-pentene oxide selectivity, with reference to the peroxidation products formed, was 94%. The pentane in the mixture was unaffected.

EXAMPLE 7 lOg of a particulate titanium aluminosilicate catalyst was dispersed in 60me of sand, and placed in a fixed bed tubular reactor. A liquid feedstock comprising 97% propylene/3% propane mixture (proportions on a mass basis) was introduced at a pressure of 20 bar and at a rate of 2, lg/min into the reactor. Simultaneously a mixture of methanol, hydrogen peroxide and water, in a ratio of 63: 11: 26 on a mass % basis, was introduced at a rate of 2,4m. /min. The temperature was maintained at 36°C. With

a hydrogen peroxide conversion of 95%, 99% of propylene oxide was formed with reference to the propylene converted.

EXAMPLE 8 lOg of a particulate titanium aluminosilicate catalyst was dispersed in 60mQ of sand and placed in a fixed bed tubular reactor. A liquid feedstock comprising 97% propylene/3% propane mixture (proportions on a mass basis) was introduced at a pressure of 20 bar and at a rate of 2, lg/min into the reactor. Simultaneously a mixture of methanol, hydrogen peroxide and water, in a ratio of 63: 11: 26 on a mass % basis, was introduced at a rate of 3,4mQ/min. The temperature was maintained at 50°C. With a hydrogen peroxide conversion of 99%, 99% of propylene oxide was formed with reference to the propylene converted.

The Applicant has thus surprisingly found that, in the process of the invention, when using close-boiling Fischer- Tropsch or Fischer-Tropsch derived or refinery mixtures of olefin (s) and paraffin (s) as feedstock, the peroxidation component reacts only with the olefin (s) to produce an olefin oxide and/or a glycol product, while leaving the paraffin compound in the mixture unreacted.

It has also surprisingly been found that when the particulate titanium aluminosilicate catalyst is mixed with an inert particulate material such as sand, the selectivity towards to the epoxide is significantly improved. This is believed to be due to better heat dispersion of the exothermic reaction thereby limiting the formation of hot spots that could be the cause of by-product formation. By controlling the reaction temperature, feed rates and ratio of olefin/hydrogen peroxide introduced to the reactor, excellent conversion of hydrogen peroxide (greater than 99%) and excellent selectivities to the epoxide (99%) can be obtained.

It has previously been known to practice peroxidation on a pure olefin and oxidation on a pure paraffin separately, but it has thus now surprisingly been found that when using stoichiometric amounts of the peroxidation component and olefin when reacting the peroxidation component with an olefin/paraffin mixture, only the olefin component partakes in the peroxidation reaction, irrespective of whether short or long residence times of reaction are used.

The process thus provides a method for selectively and quantitatively producing, from a Fischer-Tropsch derived or refinery mixture of olefin (s) and paraffin (s), the corresponding olefin oxide (s) and/or glycol product (s) and unreacted paraffin (s), ie a method for selectively and quantitatively epoxidizing olefin (s) in such a mixture. It has not previously been known to treat, by means of peroxidation, a mixture of close-boiling range olefin (s) and paraffin (s), resulting in the corresponding olefin oxide and/or glycol product (s), and unreacted paraffin (s).

Reaction conditions can also be controlled to such an extent that the selectivity or product distribution is changed (depending on the alcoholic solvent, peroxidation component, residence time and temperature used) to produce corresponding glycols and glycol alkyl ethers from respective olefins in the Fischer-Tropsch or refinery mixture of olefins and paraffins. Although the reaction temperatures (typically >70°C) and retention times (typically >60 minutes) are significantly higher for producing glycols and glycol alkyl ethers than the conditions needed to produce pure olefin oxide, the paraffin remains unaffected by peroxidation treatment.

After distillation by normal means, pure olefin oxide (and/or corresponding glycol and glycol alkyl ethers), and unreacted paraffin are obtained. The unreacted paraffin may be further applied in any chemical process known to

those skilled in the art, eg oxidation, oxychlorination, dehydrogenation, aromatization, etc.

Hitherto it has been necessary, in respect of Fischer- Tropsch derived or refinery streams consisting of close- boiling mixtures of olefin (s) and paraffin (s), to separate the olefin (s) from the paraffin (s), and then subsequently to convert or react the olefin (s) and paraffin (s). This separation is not only difficult and costly, but the products obtained are mostly pure compounds of the olefin (s) and paraffin (s) with low product value. These products, in order to obtain higher value products, must then be treated in costly downstream processing to obtain the higher value products. These steps are avoided or at least minimized with the process of the present invention.