PREPARING AROMATIC HYDROCARBONS

(54) Title of invention Process for preparing aromatic hydrocarbons (51) INT CL³;C07C 1/0415/00 B01J 23/86 (21) Application No i-------------------------------- (73) Proprietor Shell Internationale Research Maatschappij B.V.{22) Date of filing Carel van Bylandtlaan 3024 Oct 1978The Hague The Netherlands (30) Priority data Holland (31) 7711719(32) 26 Oct 1977(33) Netherlands (NL) (72) Inventors Lambert Schaper (43) Application published Swan Tiong Sie10 May 1979 (45) Patent published 17 Mar 1982 (74) (52) Domestic classification Agents C5E 332 385 386 CF R. C. Rogers, B1E1162 11801284 1298 4 York Road, London, 1322 1351 1461 1617 1631 SE1 7NA 1705 1714 1729 1738 1741 1747 CB (56) Documents cited None (58) Field of search C5E (21) Application No i-------------------------------- (73) Proprietor Shell Internationale Research Maatschappij B.V.{22) Date of filing Carel van Bylandtlaan 3024 Oct 1978The Hague The Netherlands (30) Priority data Holland (31) 7711719(32) 26 Oct 1977(33) Netherlands (NL) (72) Inventors Lambert Schaper (43) Application published Swan Tiong Sie10 May 1979 (45) Patent published 17 Mar 1982 (74) (52) Domestic classification Agents C5E 332 385 386 CF R. C. Rogers, B1E1162 11801284 1298 4 York Road, London, 1322 1351 1461 1617 1631 SE1 7NA 1705 1714 1729 1738 1741 1747 CB (56) Documents cited None (58) Field of search C5EoCON)O O O)CO 00LONDON THE PATENT OFFICE GB 2 006 819 B SPECIFICATION Process for Preparing Aromatic Hydrocarbons The invention relates to a process for preparing aromatic hydrocarbons by catalytic reaction of 5 carbon monoxide with hydrogen. Hydrocarbon mixtures boiling in the gasoline range can be obtained, for instance, by straight-run distillation of crude mineral oil, by conversion of heavier mineral oil fractions, for instance, by catalytic cracking, thermal cracking and hydrocracking and by conversion of lighter mineral oil fractions, for instance, by alkalation. To improve the octane number of the hydrocarbon mixtures thus obtained, they are often subjected 5 to catalytic reforming, as a result of which the aromatics content increases. In view of the increasing need of gasoline and the decreasing reserves of mineral oil there is great interest in processes permitting the conversion in an economically justified way of carbon-containing materials not based on mineral oil, such as coal, into hydrocarbon mixtures boiling in the gasoline range. It is desirable that these hydrocarbon mixtures should have a sufficiently high octane number, as a result of which they are suitable for use as gasoline without any further refining. It is known that carbon-containing materials, such as coal, can be converted in a relatively simple way into mixtures of carbon monoxide and hydrogen by steam gasification. It is further known that mixtures of carbon monoxide and hydrogen whose H/CO molar ratio is more than 1.0 can be converted in good yield into mixtures of hydrocarbons by contacting the gas mixtures with suitable catalysts. Attempts to achieve a commercially attractive process for the preparation of gasoline from carbon containing materials, such as coal by combining the two 40 processes have met with serious objections. These objects are in the first place connected with the composition of the mixture of carbon monoxide and hydrogen that is obtained in the steam gasification and further with the 45 composition of the mixture of hydrocarbons formed in the conversion of the mixture of carbon monoxide and hydrogen. It has been found that in the steam gasification for obtaining a high yield of a mixture of carbon 50 monoxide and hydrogen and for suppressing the formation of methane, tarry products and phenols, temperatures higher than 1000⁰C should be used. It has further been found that the Hj/CO molar ratio in the product obtained in the steam 55 gasification is highly dependent on the temperature used and that at temperatures higher than 1000^oC gas mixtures are obtained in which the Hj/CO molar ratio is smaller than 1.0. Such gas mixtures are less suitable for conversion in 60 the second stage of the abovementioned combination process in which gas mixtures with a H^CO molar ratio above 1.0 are desired. An intermediate increase of the HjCO molar ratio to above 1.0 by applying the water gas shift reaction 65 to these gas mixtures with low H^CO ratio is not suitable for commercial use, because this step implies that the gas with increased H^CO molar ratio thus obtained should then be subjected to an expensive gas separation treatment to remove 70 carbon dioxide, before the gas can be converted in the second stage of the combination process. As regards the composition of the mixture of hydrocarbons formed in the conversion of the mixture of carbon monoxide and hydrogen it is 75 noted that this mixture has a very wide molecular weight distribution and that it contains hardly any aromatics. This means that only part of this mixture consists of hydrocarbons boiling the gasoline range and that, moreover, before this 80 part can be used as gasoline it first has to be subjected to a catalytic reforming treatment to increase the aromatics content. The Applicant has carried out an extensive investigation to examine to what extent it is 85 possible to prepare from mixtures of carbon monoxide and hydrogen such as are obtained in the high-temperature steam gasification of carbon-containing materials such as coaj, aromatic hydrocarbon mixtures with a 90 high octane number that are suitable for use as gasoline without any further refining. In the investigation emphasis has been placed on the implementation of this conversion in one stage. It has been found that the abovementioned 95 requirements can indeed be met by contacting the gas mixture with a catalyst which combines three functions. In the first place the catalyst should comprise one or more metal components having catalytic activity for the conversion of a 100 H/CO mixture into hydrocarbons and/or oxygen-containing hydrocarbons. The catalyst should further contain a crystalline silicate which a) is thermally stable to temperatures higher than600⁰C, 105 b) is capable of absorbing, after dehydration at 400^oC in vacuum, more than 3%w water at 25⁰C and saturated water vapour pressure, and c) has, in dehydrated form, the following overall composition, expressed in moles of the 110 oxides. (1.0±0.3)(R)_2/nO./a Fe^g. b A\₂0₃. c Ga^ / .ytd Si0₂. eGe0₂). where R=one or more mono- or bivalent cations 115 a>0.1 b>0, c>0, a+b+c=1. y>io, 120 d>0.1, e>0, d+e=1, and n=the valency of R. Finally, thecatalyst should contain one or more 125 metal components having catalytic activity for the water gas shift reaction.

GB 2 006 819 8 The present patent application therefore relates to a process for preparing aromatic hydrocarbons by catalytic reaction of carbon monoxide with hydrogen in which process a 5 mixture of carbon monoxide and hydrogen whose H/CO molar ratio is less than 1.0 is converted in one step into an aromatic hydrocarbon mixture by contacting the gas mixture with a trifunctional catalyst containing one or more metal components having catalytic activity for the conversion of a HJCO mixture into hydrocarbons and/or oxygen-containing hydrocarbons, one or more metal components having catalytic activity for the water gas shift reaction and a crystalline b silicate as defined hereinbefore. The process according to the invention starts from a mixture of carbon monoxide and hydrogen whose HJCO molar ratio is less than 1.0. As was mentioned earlier, such a mixture can be readily prepared by steam gasification of a carbon-containing material at a high temperature. Examples of such materials are brown coal, anthracite, coke, crude mineral oil and fractions thereof, as well as oils extracted from tar sand and bituminous shale. During the steam gasification the feed, in finely divided form, is converted with steam and oxygen or air, if desired enriched with oxygen, into a gas mixture containing, inter alia, hydrogen, carbon monoxide, carbon dioxide, nitrogen and water. The steam gasification is preferably carried out at a temperature between 1000 and 2000^oC and a pressure between 10 and 50 bar. In order to be able to remove contaminants such as ash, carbon-containing material and hydrogen sulphide from the gas obtained in the steam gasification, which has a temperature higher than 1000⁰C, this gas should first be cooled down to a temperature between 100 and 200^oC. This 40 cooling can very suitably be effected in a boiler in which steam is generated with the aid of the waste heat. The cooled gas can be freed from nearly all solid components by washing it with water. After this washing treatment, during which 4b the temperature of the gas has fallen to 20— 30^oC, the gas is further purified by removal of hydrogen sulphide and carbon dioxide. This may very suitably be effected with the aid of the ADIP process or the SULFINOL process. 50 The trifunctionai catalysts which are used in the process according to the invention contain, in addition to the metal components, a crystalline silicate of a special class. These silicates effect a high conversion of aliphatic hydrocarbons into 55 aromatic hydrocarbons in commercially desirable yields and they are in genera! very active in conversion reactions in which aromatic hydrocarbons are involved. In the process according to the invention 60 preference is given to the use of silicates in which no gallium or germanium are present, in other words: silicates of which, in the above-mentioned overall composition, c and e are 0. Such silicates are the subject of Netherlands patent application 65 No. 7,613,957. Further, in the process according to the invention preference is given to the use of silicates of which, in the above-mentioned overall composition, a is greater than 0.3 and in particular of which a is greater than 0.5. Particular 70 preference is given to silicates in which no aluminium is present, in other words: silicates of which in the above-mentioned overall composition b is 0. It should be noted that in the silicates which are used in the process according 75 to the invention, y is preferably less than 600 and in particular less than 300. Finally, in the process according to the invention preference is given to silicates whose X-ray powder diffraction pattern has, inter alia, the reflections given in Table A of 80 Netherlands Patent Application No. 7,613,957. The trifunctional catalysts which are used in the process according to the invention contain one or more metal components having catalytic activity for the conversion of a HJCO mixture into 85 hydrocarbons and/or oxygen-containing hydrocarbons, one or more metal components having catalytic activity for the water gas shift reaction and a crystalline silicate such as defined hereinbefore having catalytic activity for the 90 conversion of acyclic hydrocarbons and/or oxygen-containing acyclic hydrocarbons into an aromatic hydrocarbon mixture boiling in the gasoline range. The ratio in which the three catalytic functions are present in the catalyst may 95 vary within wide limits and is determined by the activity of each of the catalytic functions. For, in the process according to the invention the object is that of the acyclic hydrocarbons and/or oxygen-containing acyclic 100 hydrocarbons formed under the influence of the first catalytic function, as much as possible is converted under the influence of a second catalytic function into an aromatic hydrocarbon mixture boiling in the gasoline range, and that of 105 the water liberated in the conversion of the mixture of carbon monoxide and hydrogen into hydrocarbons and/or in the conversion of oxygen-containing hydrocarbons into an aromatic hydrocarbon mixture, as much as possible reacts 110 under the influence of a third catalytic function with the carbon monoxide present in an excess amount in the mixture of carbon monoxide and hydrogen with formation of a mixture of hydrogen and carbon dioxide. In the composition of an 115 optimum trifunctional catalyst to be used in the process according to the invention, which catalyst contains a given quantity of a first catalytic function having a given activity, it is therefore possible to do with less of the other catalytic 120 functions according as these are more active. Although the catalysts according to the invention are described in this patent application as catalysts containing one or more metal components having catalytic activity for the 125 conversion of a H/CO mixture into hydrocarbons and/or oxygen-containing hydrocarbons and one or more metal components having catalytic activity for the water gas shift reaction, this means in no way that metal components each 130 having in themselves one of the two catalytic GB 2 006 819 B functions should always separately be present in the catalysts according to the invention. For, it has been found that metal components and combinations of metal components having 5 catalytic activity for the conversion of a Hj/CO mixture into oxygen-containing hydrocarbons as a rule also have sufficient catalytic activity for the water gas shift reaction, so that in such a case incorporation of one metal 10 component or one combination of metal components into the catalysts according to the invention will suffice. Examples of such metal components are the metals chosen from the group formed by the metals zinc, copper and 5 chromium. When use is made of trifunctional catalysts according to the invention containing these metals, preference is given to catalysts containing combinations of at least two of these metals, for instance the combination zinc-copper, zinc-chromium or zinc-copper-chromium. Particular preference is given to a trifunctional catalyst containing, in addition to the crystalline silicate the metal combination zinc-chromium. Metal components and combinations of metal components having catalytic activity for the conversion of a H/CO mixture into hydrocarbons have as a rule no or insufficient activity for the water gas shift reaction. When use is made of such metal components or combinations of metal components in the catalysts according to the invention, one or more separate metal components having catalytic activity for the water gas shift reaction should therefore be incorporated therein. The trifunctional catalysts which are used according to the invention are preferably composed of two or three separate catalysts, which will for convenience be designated catalysts X, Y and Z. Catalyst X is the catalyst containing 40 the metal components having catalytic activity for the conversion of a Hj/CO mixture into hydrocarbons and/or oxygen-containing hydrocarbons. Catalyst Y is the crystalline silicate. Catalyst Z is the catalyst containing the metal 45 component having catalytic activity for the water gas shift reaction. As has been explained hereinbefore the use of a Z-catalyst may be omitted in some cases. If as the X-catalyst a catalyst is used which is 50 capable of converting a H^CO mixture into oxygen-containing hydrocarbons, preference is given to a catalyst which is capable of converting the H₂/CO mixture into methanol and/or dimethyl ether. For the conversion of a Hj/CO mixture into 55 methanol, catalysts containing the metal combinations mentioned hereinbefore are very suitable. If desired, the said metal combinations may be emplaced on a carrier material. By introducing an acid function into these catalysts, 60 for instance by emplacing the metal combination on an acid carrier, it may be effected that apart from the conversion of the H^/CO mixture into methanol a considerable part of the mixture will be converted into dimethyl ether.

65 X-catalysts which are capable of converting a H/CO mixture into hydrocarbons are referred to in the literature as Fischer-Tropsch catalysts. Such catalysts often contain one or more metals of the iron group or ruthenium 70 together with one or more promoters to increase the activity and/or selectivity and sometimes a carrier material such as kieselguhr. They can be prepared by precipitation, melting and by impregnation. The preparation of the catalysts 75 containing one or more metals of the iron group by impregnation, takes place by impregnating a porous carrier with one or more aqueous solutions of salts of metals of the iron group and, optionally, of promoters, followed by drying and 80 calcining the composition. If in the process according to the invention use is made of a catalyst combination in which catalyst X is a Fischer-Tropsch catalyst, it is preferred to choose for this purpose an iron or cobalt catalyst, in 85 particular such a catalyst which has been prepared by impregnation. Very suitable Fischer-Tropsch catalysts for use in the catalyst combinations according to the invention are the catalysts prepared by impregnation according to 90 the Netherlands Patent Application No. 7,612,460. The catalysts concerned contain per 100 pbw carrier 10—75 pbw of one or more metals of the iron group, together with one or more promoters in a quantity of 1—50% of the 95 quantity of metals of the iron group present on the catalyst, which catalysts have such a specific average pore diameter (p) of at most 10,000nm and such a specific average particle diameter (d) of at most 5 mm that the quotient p/d is more 100 than 2 (p in nm and d in mm). If in the process according to the invention the object is to use a catalyst combination of which X is a Fischer-Tropsch iron catalyst, it is preferred to choose an iron catalyst containing a promoter 105 combination consisting of an alkali metal, a metal that is easy to reduce, such as copper or silver and optionally, a metal which is hard to reduce, such as aluminium or zinc. A very suitable iron catalyst for the present purpose is a catalyst prepared by 110 impregnation containing iron, potassium and copper on silica as the carrier. If in the process according to the invention the object is to use a catalyst combination ofwhich X is a Fischer-Tropsch cobalt catalyst, it is preferred to choose a 115 cobalt catalyst containing a promoter combination consisting of an alkaline-earth metal and thorium, uranium or cerium. A very suitable Fischer-Tropsch cobalt catalyst for the present purpose is a catalyst prepared by impregnation 120 containing cobalt, magnesium and thorium on silica as the carrier. Other very suitable Fischer-Tropsch cobalt catalysts prepared by impregnation are catalysts containing, in addition to cobalt, one of the 125 elements chromium, titanium, zirconium and zinc on silica as the carrier. If desired, it is also possible to use in the process according to the invention catalyst combinations containing an X-catalyst, which is capable of converting a H^CO mixture GB 2 006 819 B into a mixture containing both hydrocarbons and oxygen-containing hydrocarbons in comparable quantities. As a result, such a catalyst has sufficient catalytic activity for the water gas shift 5 reaction, so that the use of a Z-catalyst in the 70 combination can be omitted. An example of an X-catalyst of this type is an iron-chromium oxide catalyst. If desired, it is also possible to use in the process according to the invention catalyst combinations containing two or more X-catalysts, 75 for instance in addition to a catalyst of the X-type which is capable of converting a HJCO mixture into hydrocarbons, a second catalyst of the X-type which is capable of converting a H/CO mixture 5 into oxygen-containing hydrocarbons. 80 Z-catalysts which are capable of converting a H-j/CO mixture into a H₂/C0₂mixture are referred to in the literature as CO-shift catalysts. Such catalysts often contain one or more metals of the group formed by iron, chromium, copper, zinc, 85 cobalt, nickel and molybdenum as the catalytically active component, either as such, or in the form of their oxides or sulphides. Examples of suitable CO-shift catalysts are the mixed sulphidic catalysts according to the Netherlands 90 Patent Applications No. 7,305,340 and No. 7,304,793 and the spinel catalysts according to the French Patent Application No. 7,633,900. If in the process according to the invention use is made of a catalyst combination in which a Z- gg catalyst is present, it is preferred to choose a catalyst which contains both copper and zinc, in particular a catalyst in which the Cu/Zn atomic ratio ties between 0.25 and 4.0. In the trifunctional catalysts the catalysts X, Y ] qq and, optionally, Z may be present as a mixture, in which, in principle, each particle of catalyst X is surrounded by a number of particles of catalyst Y and, optionally, catalyst Z and conversely. If the 40 process is carried out with use of a fixed catalyst 105 bed, this bed may be built up of alternate layers of particles of catalysts X, Y and, optionally, Z. If the two or three catalysts are used as a mixture, this mixture may be a macromixture or a 45 micromixture. In the first case the trifunctional prepared by incorporating the metal components having catalytic activity for converting a H^CO mixture into hydrocarbons and/or oxygen-containing hydrocarbons and, optionally, the metal components having catalytic activity for the water gas shift reaction into the crystalline silicate, for instance by impregnation or by ion exchange. The crystalline silicates which are used in the trifunctional catalysts according to the invention are usually prepared from an aqueous mixture as the starting material which contains the following compounds in a given ratio; one or more compounds of an alkali or alkaline-earth metal, one or more compounds containing a mono- or bivalent organic cation or from which such a cation is formed during the preparation of the silicate, one or more silicon compounds, one or more iron compounds, and, optionally, one or more aluminium, gallium and/or germanium compounds. The preparation is effected by maintaining the mixture at elevated temperature until the silicate has been formed and then separating the crystals of the silicate from the mother liquor. The silicates thus prepared contain alkali and/or alkaline-earth metal ions and mono-and/or bivalent organic cations. Before being used in the trifunctional catalysts according to the invention at least part of the mono- and/or bivalent organic cations introduced during the preparation are preferably converted into hydrogen ions, for instance by calcining and at least part of the exchange mono- and/or bivalent cations introduced during the preparation are preferably replaced by other ions, in particular hydrogen ions, ammonium ions and/or ions of the rare-earth metals. The crystalline silicates used in the trifunctional catalysts according to the invention preferably have an alkali metal content of less than 1 %w and in particular of less than 0.05 %w. If desired, a binder material such as bentonite or kaolin may be incorporated in the trifunctional catalysts. The process according to the invention preferably starts from a mixture of carbon monoxide and hydrogen whose H/CO molar ratio is more than 0.4. The process according to the invention is preferably carried out at a temperature of from 200 to 500⁰C and in particular of from 300 to 450^oC, a pressure of from 1 to 1 50 bar and in particular of from 5 to 100 bar and a space velocity of from 50 to 5000 and in particular of from 300 to 3000 Nl gas/I catalyst/hour. The process according to the invention can very suitably be carried out by passing the feed in upward or in downward direction through a vertically disposed reactor in which fixed or a moving bed of the trifunctional catalyst concerned is present. The process may, for instance, be carried out in the so-called fixed-bed operation, in bunker-flow operation or in ebulated-bed operation. It is preferred to use catalyst particles catalyst consists of two or three kinds of macroparticles of which one kind is completely made up of catalyst X, the second kind completely of catalyst Y and, optionally, a third kind 50 completely of catalyst Z. In the second case the trifunctional catalyst consists of one kind of macroparticles, each macroparticle being made up of a large number of microparticles of each of the catalysts X, Y and, optionally, Z. Trifunctional 55 catalysts according to the invention in the form of micromixtures may be prepared, for instance, by thoroughly mixing a fine powder of catalyst X with a fine powder of catalyst Y and, optionally, with a fine powder of catalyst Z and shaping the 60 mixture to larger particles, for instance, by extruding or pelletizing. In the process according 125 to the invention it is preferred to use trifunctional catalysts in the form of micromixtures. The trifunctional catalysts which are used 65 according to the invention may also have been GB 2 006 819 B then with a diameter between 1 and 5 mm. If desired, the process may also be carried out in fluidized-bed operation or with the use of a suspension of the catalyst in a hydrocarbon oil. It 5 is preferred to use catalyst particles then with a diameter between 10 and IBO^m. The invention will now be explained with reference to the following examples. Example I10 A crystalline iron silicate (silicate A) was prepared as follows. A mixture of FedMOg^, Si0₂, NaN0₃and [(C₃H₇)₄N]0H in water with the molar composition higher than 1000^oC and was capable, after a dehydration at 400^oC in vacuum, of adsorbing 8%w water at 25⁰C and saturated water vapour pressure. With silicate C as the starting material 60 silicate D was prepared in the same way as described for the preparation of silicate B from silicate A. Example 111 A catalyst was prepared by mixing a ZnOCr₂0₃ 65 composition with the crystalline iron silicate B in a weight ratio of 3:1. Both materials were present in the catalyst in the form of particles with a diameter of 0.1 5—0.3 mm. The ZnO-Cr₂0₃ composition used catalyses both the reduction of 70 CO to methanol and the water gas shift reaction. The catalyst obtained by mixing was tested for the one-stage preparation of an aromatic hydrocarbon mixture starting from a mixture of carbon monoxide and hydrogen. The testing was 75 carried out in a 50-ml reactor, in which a fixed catalyst bed having a volume of 7.5 ml was present. A mixture of carbon monoxide and hydrogen with a H^CO molar ratio of 0.5 was passed across the catalyst at a temperature of 80 375⁰C, a pressure of 60 bar and a space velocity of 1000 Nl gas/I catalyst/h. The results of this experiment are given below Na₂0 . 1.5[{C3H₇)₄N]₂0 . 0.125- Fe^ . 25SiO_: .468H₂0 was heated for 48 hours in an autocalve at 150⁰C under autogeneous pressure. After the reaction mixture had cooled down, the silicate formed was filtered off, washed with water until the pH of the 20 wash water was about 8 and dried for two hours at 120⁰C. Silicate A thus prepared had the following chemical composition 0.8[(C3H₇)₄N]₂0 . 0.3Na₂0 . Fe₂0₃ . 200SiO₂ . 55 H₂0. The silicate had an X-ray powder diffraction pattern substantially as given in Table B of Netherlands Patent Application No. 7,613,957. The silicate was thermally stable to temperature higher than 900^oC and was capable, after dehydration at 400^oC in vacuum, of absorbing 7 %w water at 25⁰C and saturated water vapour pressure. With silicate A as the starting material silicate B was prepared by successively calcining silicate A at 500⁰C boiling with 1.0 molar NH₄N0₃ solution washing with water, boiling again with 1.0 molar NH₄N0₃ solution and washing, drying for two hours at 120^oC and calcining for four hours at 500^oC. Example II40 A crystalline silicate {silicate C) was prepared in substantially the same way as silicate A, the difference being that in the present case the starting material was an aqueous mixture which contained, in addition to FelNOg)^ AI(N0₃)₃ and 45 which had the following molar composition: Na₂0 . 4.5[{C₃H₇)₄N]₂0 . O.SSAIA, . 0.1 5Fe₂0₃ .29.1Si0₂.468H₂0. Silicate C thus prepared had the following chemical composition: CO conversion, % H₂ conversion, %Product composition.%w on<v^hproductc,c₂c₃c₄c₅-c₁₂C,3⁺ CO conversion, % H₂ conversion, %Product composition.%w on<v^hproductc,c₂c₃c₄c₅-c₁₂C,3⁺ C₅⁺product composition, %w on C₅⁺product paraffins+olefins 20 naphthenes 27 aromatics 53 Example IV A catalyst was prepared by mixing the ZnO-Cr₂0₃ composition of Example III with the crystalline iron-aluminium silicate D in a weight 100 ratio of 5:1. Both materials were present in the catalyst in the form of particles with a diameter of 0.1 5—0.3 mm. This catalyst was tested for the one-stage preparation of an aromatic hydrocarbon mixture starting from a mixture of 105 carbon monoxide and hydrogen with a HJCO molar ratio of 0.5. The testing was carried out in substantially the same way as described in Example III, the differences being that in the present case a 110 temperature of 350^oC and a pressure of 80 bar were used. The results of this experiment are given below 50 0.35[{C₃H₇)₄NJ₂0 . 0.2Na₂0 . 0.1 SFe^ .0.35A!₂O3.31SiO₂.9H₂O. The silicate had an X-ray powder diffraction pattern substantially as given in Table B of Netherlands Patent Application No. 7,613,957. 55 The silicate was thermally stable to temperatures CO conversion, % H₂ conversion, % 54 59 GB 2 006 819 B Product composition, %w on C,"¹" product 40 a>0, 1, b>0,c>0, a+b+c=1, Y>10, 45 d>0.1, e>0, d+e— 1, and n=the valency of R. 2. A process according to Claim 1, 50 characterized in that the trifunctional catalyst is composed of three separate catalysts of which the first catalyst (catalyst X) contains the metal components having catalytic activity for the conversion of a H₂/C0 mixture into hydrocarbons, 55 the second catalyst (catalyst Y} is the crystalline silicate and the third catalyst (catalyst Z) contains the metal components having catalytic activity for the water gas shift reaction. 3. A process according to Claim 2, 60 characterized in that catalyst X is an iron or cobalt catalyst. 4. A process according to Claim 2, characterized in that catalyst Z is a catalyst which contains both copper and zinc, preferably with a 65 Cu/7n atomic ratio between 0.25 and 4.0. 5. A process according to any one of Claims 2—4, characterized in that a trifunctional catalyst is used which consists of one kind of macroparticles, each macroparticle being built up 70 of a large number of microparticles of each of the catalysts X, Y and, optionally Z. 6. A process according to any of Claims 1—5, characterized in that it is carried out at a temperatue of from 200 to 500⁰C and preferably 75 of from 300 to 450^oC, a pressure of from 1 to 1 50 bar and preferably of from 5 to 100 bar and a space velocity of from 50 to 5000 and preferably of from 300 to 3000 Nl gas/I catalyst/h. 7. Aromatic hydrocarbon mixtures which have 80 been prepared with use of a process according to any one or more of Claims 1 —6.

C₂ c⁺ C₅⁺product composition, %w on C₅⁺product paraffins+olefins 18 naphthenes 20 aromatics 62 Claims 1. A process for preparing aromatic hydrocarbons by catalytic reaction of carbon 5 monoxide with hydrogen, characterized in that a mixture of carbon monoxide and hydrogen, whose Hj/CO molar ratio is less than 1.0, is converted in one step into an aromatic hydrocarbon mixture by contacting the gas mixture with a trifunctional catalyst containing one or more metal components having catalytic activity for the conversion of a H/CO mixture into hydrocarbons and/or oxygen-containing hydrocarbons, one or more metal components having catalytic activity for the water gas shift reaction and a crystalline silicate which a)is thermally stable to temperatures higher "than 600^oC, b)is capable of absorbing, after dehydration at 30 400^oC in vacuum, more than 3%w water at 25⁰C and saturated water vapour pressure, and c)has, in dehydrated form, the following overall composition, expressed in moles of the oxides, (1.0±0.3HR}_2/nO./a Fe₂0₃. b Al₂0₃. c Ga₂Oj .y(dSi0₂ eGe0₂), where R—one or more mono-or bivalent cations.

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