NL8002416A - Crystalline aluminium silicate(s) prepn. - useful as catalysts for prodn. of aromatic cpds. from four-carbon mono:olefin(s) or hydrogen-carbon mon:oxide mixts. - Google Patents

Abstract

Crystalline aluminium silicates are made which after calcining for 1 hour in air at 500 deg.C have the following properties: (a) thermally stable to above 600 deg.C; (b) X-ray powder diffraction pattern in which the four strongest lines are (as d(Angstroms)/relative intensity) 11.1 +/- 0.2, very strong; 10.0 +/- 0.2, very strong; 3.84 +/- 0.07, strong; and 3.72 +/- 0.06, strong; and (c) a formula, expressed in moles of oxides, of Al2O3/SiO2 of less than 0.05. The silicates are made by forming an aq. mixt. contg. one or more quat. alkylammonium cpds. R4NX; one or more Si cpds. which after drying at 120 deg.C and calcining at 500 deg.C gives a prod. with a SiO2 content of more than 90 wt.%; and one or more aluminium cpds. which after drying at 120 deg.C, produce a prod. with a content of elements other than Al, O or H of less than 1 wt.%. The molar ratios (R4N)20:SiO2 is 0.01-0.40; H2O:SiO2 is 5-65 and Al2O3:SiO2 is less than 0.05. The mixt. has an alkali metal (M) content such that M2O/Al2O3 is less than 0.2. The mixt. is maintained at an elevated temp. until the crystalline silicate is formed, and this is then recovered and calcined. The silicates are useful catalysts showing good activity and selectivity in the prodn. of aromatic hydrocarbon mixts. from C4 monoolefins or a hydrocarbon mixt. contg. more than 75 wt.% C4 monoolefins; and also in the prodn. of aromatic hydrocarbons from H2/CO mixts.

Description

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K 5532 NET

PROCESS FOR THE PREPARATION OF CRYSTALLINE SILICATES

The invention relates to a process for the preparation of crystalline aluminum silicates with improved catalytic properties.

Mono-olefins with up to four carbon atoms in the molecule (C 3 "mono-olefins) as well as hydrocarbon mixtures consisting of more than 75 wt.% Of C 3" mono-olefins can be converted to aromatic hydrocarbon mixtures using certain crystalline aluminum silicates as a catalyst. Said crystalline silicates are characterized in that after calcining in air at 500 ° C for one hour, they have the following properties a) thermally stable up to a temperature above 600 ° C, b) an X-ray powder diffraction pattern showing the four lines listed in Table 15A as strongest lines contains c) in the formula which represents the composition of the silicate expressed in moles of the oxides, the AlgO2 / SiO8 mole ratio (further referred to as m in this patent application for brevity) is less than 0.05.

8002416 -2-

Table A

d (£) Relative intensity

11.1 + 0.2 ZS

10.0 + 0.2 ZS

3.84 + 0.07 S

3.72 + 0.06 S

in which the letters used have the following meanings ZSs very strong; S = strong.

The silicates in question can be prepared from an aqueous mixture containing the following compounds: one or more compounds of an alkali metal (M), one or more quaternary alkyl ammonium compounds CR ^ NX), one or more silicon compounds with a high SiO2 content and one or more aluminum compounds.

In this patent application, silicon compounds with a high SiOg content are understood to be silicon compounds which, after drying at 120 ° C and calcining at 500 ° C, yield a product with a SiOg content of more than 90% by weight. The aluminum compounds used in the preparation of the crystalline silicates can be classified into two classes due to the content of elements other than aluminum, oxygen and hydrogen of the product obtained from these compounds after drying at 120 ° C. classified, viz aluminum compounds which provide a product with a content of elements other than aluminum, oxygen and hydrogen of less than 1 wt.% and aluminum compounds which provide a product with a content of elements other than aluminum, oxygen and hydrogen of at least 1 wt.% . For the sake of brevity, aluminum compounds which are suitable for use in the preparation of the crystalline silicates will be referred to hereinafter as layer aluminum compounds, respectively, in the light of the above-mentioned classification. high content of 8002416 * -3 elements other than A1.0 and H. Examples of aluminum compounds with low content of elements other than A1.0 and H are amorphous alumina and aluminum hydroxide.

Examples of aluminum compounds with a high content of elements other than A1.0 and H are sodium aluminate, aluminum sulfate and aluminum nitrate. The crystalline silicates are prepared by keeping the aqueous mixture at an elevated temperature until the crystalline silicate is formed, separating it from the mother liquor and calcining. In the aqueous mixture from which the silicates are prepared, the various compounds should be present in the following proportions, expressed in moles of the oxides, M 2 O: SiO 2 <0.35, 15 '(R 2 NJO: SiO 2. 0.01- 0.40, H 2 O, SiO 2 5-65, and Al 2 O 3: SiO 2 <0.05 In an investigation by the Applicant into the use of the above-mentioned silicates as catalysts for the preparation of aromatic hydrocarbon mixtures from C4-mono-olefins and from hydrocarbon mixtures which for more than 75 wt.% of C 1-4 mono-olefins, it has been found that the aromatic selectivity of these catalysts is largely determined by the MgO / A 2 O 2 mole ratio in the aqueous mixture from which the crystalline silicates are prepared, it has been found that the aromatic selectivity of the catalysts decreases as a higher M 2 / AlgOg mole ratio is used in the aqueous mixture and that using a MgO / Al 2 mole ratio of 0.2 or higher, catalysts with an unacceptable low aromatics selectivity is obtained. Admittedly, the aromatic selectivity of catalysts prepared using a molar ratio of 0.2 or higher in the aqueous mixture can be improved by subjecting the crystalline silicates to a treatment in which at least part of the 8002416-4- alkali metal ions present are exchanged for other cations, but this requires one or more additional process steps, which makes the catalyst more expensive. Further research by the Applicant regarding the use of the crystalline silicates prepared using a MgO / AlgO2 molar ratio of less than 0.2 in the aqueous mixture for the above catalytic application has shown that the stability of the Aromatic selectivity of these catalysts is largely determined by the nature of the aluminum compound present in the aqueous mixture from which the crystalline aluminum silicate is prepared. It has been found that catalysts for the above application with excellent stability of the aromatic selectivity can be prepared from an aqueous mixture in which the

MjO / AlgO2 molar ratio is less than 0.2 if one or more aluminum compounds with a low content of elements other than Al, O and H are incorporated therein. The preparation of crystalline aluminum silicates which have the properties mentioned under a) -c), starting from an aqueous mixture in which the M 2 O / A 1 0 0 mol ratio is less than 0.2 and in which one or more aluminum compounds with a low content of elements other than A1, H and 0 is new.

The present application therefore relates to a new preparation method for crystalline aluminum silicates which have the properties mentioned under a) -c), wherein an aqueous mixture containing the following compounds! one or more quaternary alkyl ammonium compounds (RjjNX), one or more silicon compounds with a high SiOg content and one or more aluminum compounds, with a low content of elements other than A1.0 and H, in which mixture the different compounds in the following ratios, expressed 8002416 * * -5- in moles of the oxides, are present (R4N) 20: SiO2 = 0.01-0.40,

HgO: SiO 2 s 5-65, and Al 2 O 3 SiO 2 <0.05, 5 and which mixture has such a low content of alkali metals (M) that the MgO / AlgO 2 mol ratio in the mixture is less than 0.2 is held at an elevated temperature until the crystalline silicate is formed and then separated from the mother liquor and calcined.

The silicates prepared according to the invention are defined, inter alia, by means of the X-ray powder diffraction pattern. This should include the four lines listed in Table A as the strongest lines. The complete X-ray powder diffraction pattern of a typical example of a silicate prepared according to the invention is shown in Table B

Table B

d (fl) _Rel, int._ d (%) _ Rel, int.

11.1 100 4.00 3 10.0 70 3.84 57 8.93 1 3.72 31 7.99 1 3.64 10 7.42 1 3.44 5 6.68 7 3.34 3 6.35 11 3.30 5 5.97 18 3.25 2 5.70 7 3.05 5 5.56 10 2.98 12 5.35 2 2.96 3 4.98 6 2.86 2 4.60 4 2.73 2 4.35 5 2, 60 2 4.25 7 2.48 3 4.07 2 2.40 2 800 24 1 6 -6-

The preparation of the silicates can be carried out both at atmospheric pressure and at elevated pressure. If reaction temperatures above the boiling point of the mixture are used, it is preferred to work in an autoclave under autogenous pressure. The silicates are preferably prepared by keeping the mixture at a temperature between 90 and 300 ° C and in particular at a temperature between 125 and 175 ° C for at least four hours. After the formation of the silicates, the crystals are separated from the mother liquor, for example, by filtration, decantation or centrifugation. The crystal mass is then washed with water and finally dried and calcined.

As examples of suitable compounds which can be used in the preparation of the silicates according to the invention, mention can be made of quaternary alkyl ammonium bromides and hydroxides; amorphous solid silicas, silica sols, silica gels and silicic acid; aluminum hydroxide, and amorphous alumina. The silicates according to the invention are preferably prepared from an aqueous mixture in which RjNX is a tetrapropylammonium compound. In the preparation of the silicates according to the invention, it is further preferred to start from an aqueous mixture in which the aluminum-25 and silicon compounds, expressed in moles of the oxides, are present in a ratio of greater than 0.002 and in particular greater than 0, 0025.

Silicates prepared according to the invention can be used, inter alia, as an adsorbent and extractant, as a drying agent, as an ion exchanger and as a catalyst or catalyst support in the implementation of various catalytic processes, in particular the catalytic preparation of aromatic hydrocarbons from acyclic organic compounds. When used as a catalyst, the crystalline aluminum silicas can optionally be combined with a binder material such as bentonite or kaolin.

As noted above, an important application of the silicates prepared according to the invention is their use as a catalyst in the preparation of an aromatic hydrocarbon mixture from a mono-olefin or from a hydrocarbon mixture containing more than 75 weight percent of C Mono-olefins exist. The following can be considered as C-mono-olefins ethylene, propylene, butene 10 and iso-butene. If a hydrocarbon mixture is used which contains one or more other hydrocarbons in addition to one or more C 10-mono-olefins. these other hydrocarbons may be, inter alia, paraffins, diolefins or C + mono-olefins Preferably, one or 15 µl mono-olefin or a hydrocarbon mixture consisting essentially of one or more of these mono-olefins is used.

A very suitable feed is a hydrocarbon mixture consisting essentially of and / or Cjj mono-olefins obtained as a by-product in the catalytic or thermal cracking of hydrocarbons, in particular in the thermal cracking of hydrocarbons to prepare ethylene. The process is preferably carried out at a temperature of 300-550 ° C and in particular of 350-500 ° C, a pressure of 3-20 bar and in particular of 5-15 bar and a spatial throughput speed - 1 -1 of 1-20 µg. Hour and in particular of 2-10 µg. If desired, the process can be carried out in the presence of hydrogen. In the process, preference is given to the use of crystalline aluminum silicates prepared according to the invention for which 0.0075 µm ^ 0.0030 applies and which have a crystallite size of at most 500 nm.

Crystalline aluminum silicates prepared according to the invention are also very suitable for use as a catalyst component in the preparation of 8002416-8 aromatic hydrocarbon mixtures from H 2 / CO mixtures. This conversion is preferably carried out by contacting a Hg / CO mixture having a Hg / CO molar ratio below 1.0 with a mixture of two catalysts, one of which has the ability to convert a U / CO mixture in acydic oxygenated hydrocarbons and the other is the crystalline aluminum silicate. H2 / CO2 mixtures with an H2 / CO2 molar ratio below 1.0 can very suitably be prepared by steam gasification of coal at a temperature of 900-1500 ° C and a pressure of 10-50 bar.

As regards the catalysts which have the ability to catalyze the conversion of an H 2 / C0 mixture into acyclic oxygen-containing hydrocarbons, catalysts capable of converting an H 2 / C0 mixture into essentially oxygen are preferred. methanol and / or dimethyl ether. Particular preference is given to catalysts containing the metal combination Zn-Cr. The conversion of the H2 / CO mixture into an aromatic hydrocarbon mixture is preferably carried out at a temperature of 200-500 ° C and in particular of 250-450 ° C, a pressure of 1-150 bar and in particular of 5 -100 bar and a spatial throughput of 50-5000 and in particular 300-3000 25 NI gas / 1 catalyst / hour. The above-described conversion using a mixture of a crystalline aluminum silicate prepared according to the invention and a catalyst which has the ability to catalyze the conversion of a Hg / CO mixture into acydic oxygen-containing hydrocarbons can also be very suitably used as first step in a two-step process for the conversion of an H 2 / CO mixture with an Hg / CO molar ratio below 1.0 into an aromatic hydrocarbon mixture. In this case, of the reaction product of the first step, at least the C 2 "fraction in 8002416 -9-, a second step is contacted with a catalyst containing one or more metal components with catalytic activity for the conversion of an H 2 / CO mixture to acyclic hydrocarbons, which metal components are selected from the group consisting of cobalt, nickel and ruthenium, with the proviso that if the feed for the second step has an H 2 / CO molar ratio of less than 1.5, water is added to this feed and a bifunctional catalyst combination is used in the two step which, in addition to the metal components with catalytic activity for the conversion of an H 2 / CO mixture to acyclic hydrocarbons, additionally contains one or more metal components with catalytic activity for the conversion of an H 2 / CO mixture to an H 1 / CO2 mixture.

The invention is now illustrated by the following example.

Example

Four crystalline aluminum silicates (silicates I-IV) were prepared by heating mixtures containing amorphous silica, (C 2 H 2 J NOH and water) in an autoclave at 150 ° C for 24 hours. The aqueous mixtures from which the silicates were prepared additionally contain:

For the preparation of silicate X NaAlOg + NaOH 25 "" "" "II A1 (NO3) 3" "" "" III amorphous alumina

w "" "" IV amorphous alumina + NaOH

After cooling the reaction mixtures, the resulting silicates were filtered off, washed with water until the pH of the wash water was about 8, dried at 120 ° C and calcined at 500 ° C. The silicates I-IV had the following properties a) thermally stable to a temperature above 800 ° C, 8002416 -10-b) an X-ray powder diffraction pattern substantially corresponding to that stated in Table B,

c) a value for m as listed in Table C.

Table C

Silicate No. m I 0.0066 II 0.0059 III 0.0059 IV 0.0061 5 The amorphous silica used in the preparation of the silicates I-IV yielded a product after drying at 120 ° C and calcining at 500 ° C which was 99.97 wt.% SiO4.

The amorphous alumina used in the preparation of the silicates III and IV 10 yielded, after drying at 120 ° C, a product consisting of more than 99.9% by weight of Al.0 and H.

In the composition of the aqueous mixtures from which the silicates I-IV were prepared, use was made of a 25 water aqueous (C-H7) NNOH solution containing traces of 3 '(RN) 0 alkali metal (M). The 2 mol ratio is the solution was about 225. 2

The molar composition of the aqueous mixtures from which the silicates I-IV were prepared can be represented as follows: 25 SiO 2. 0.125 A1203x MgO. 4.5 / C ^ J ^ O. 450 H2O where x has the value shown in Table D. Table D also lists the MgO / AlgO2 molar ratio in the aqueous mixtures.

Table D

Silicate No. x M20 / A1203 I 1.02 8.16 II 0.02 0.16 III 0.02 0.16 IV 0.12 0.96 8002 416 -11-From silicate I, a silicate V was prepared by adding at 500 Boil ° C calcined material with 1.0 molar NH 2 NO 3 solution, wash with water, boil again with 1.0 molar NH 2 NO 3 solution and wash, dry at 120 ° C and calcine at 500 ° C.

The silicates I-V were tested as a catalyst for the preparation of an aromatic hydrocarbon mixture from isobutylene. The test was carried out in a 50 ml reactor containing a fixed catalyst bed with a volume of 5 ml consisting of the respective silicate. Isobutene was passed over the catalyst at a temperature of 400 ° C, a pressure of 10 bar, a spatial flow rate of 3.4 g of isobutene / g of silicate / hour and a Hg / isobutene molar ratio of 5: 1. The results of these experiments are shown in Table E. In this table, the aromatic selectivities are expressed as yield of aromatics in weight based on isobutene feed.

Table E

Experiment No. 12345

Silicate No. I II III IV V

Aromatic Selectivity, Wt% After 1 Day 2 20 22 5 23 After 10 Days 0.1 5 18 1 19 20 Of the silicates listed in Table D, only silicate III was prepared according to the invention. The silicates I, II and IV from table D as well as silicate V are outside the scope of the invention. They are included in the patent application for comparison.

Of the experiments listed in Table E, only Experiment 3 was conducted using a catalyst prepared according to the invention. In this experiment, both high aromatic selectivity and high stability of aromatic selectivity were achieved. Experiments 1,2,4 and 5 are outside the scope of the invention and are included for comparison. In experiments 1,2 and 4, an unacceptably low aromatic selectivity and / or an unacceptably low stability of aromatic selectivity was observed. In Experiment 5, although a high aromatic selectivity as well as a high stability of aromatic selectivity was achieved, this experiment was carried out with a silicate which had previously been subjected to two ion exchange treatments.

8002416

Claims (25)

A process for the preparation of crystalline aluminum silicates which, after calcination in air at 500 ° C for one hour, have the following properties a) thermally stable up to a temperature above 600 ° C, 5 b) an X-ray powder diffraction pattern which shows the four lines shown in Table A as strongest lines contains Table A d (£) Relative intensity 11.1 +0.2 ZS 10.0 + 0.2 ZS 3.84 + 0.07 s 3.72 + 0.06 S in which the letters used have the following meaning have ZS = very strong; S = strong, and c) in the formula representing the composition of the silicate expressed in moles of the oxides, the AlgO2 / SiO2 molar ratio (m) is less than 0.05, characterized in that a aqueous mixture containing the following compounds: one or more quaternary alkylaramonium-15 compounds (R ^ NX), one or more silicon compounds which, after drying at 120 ° C and calcining at 500 ° C, yield a product with an SiO2 content of more than 90 parts by weight and one or more aluminum compounds, which, after drying at 120 ° C, yield a product with a content of elements other than aluminum, oxygen and hydrogen of less than 1% by weight, in which mixture the various compounds in the following molar ratios, expressed in moles of the oxides, are present (Η4Ν) 20: SiO2 = 0.01-0.40, 2. Process according to claim 1, characterized in that the al3 compound R1-NX a tetrapropylammonium compound 15 is used. Method according to claim 1 or 2, characterized in that the mixture is kept at a temperature between 90 and 300 ° C for at least four hours. 4. Method according to claim 3, characterized in that the mixture is kept at a temperature between 125 and 175 ° C. 5. Process according to any one of claims 1-4, characterized in that an aqueous mixture is started in which the aluminum and silicon compounds, expressed in moles of the oxides, are present in a ratio greater than 0.002. 5 HgO: SiO2 = 5-65, and Al2O3: SiO2 <0.05, and which mixture has such a low content of alkali metals (M) that the MgO / AlgO2 molar ratio in the mixture is less than 0.2 is held at an elevated temperature until the crystalline silicate is formed and is then separated from the mother liquor and calcined. Method according to claim 5, characterized in that said ratio is above 0.0025. 7. Process for the preparation of crystalline aluminum-30-silicates, substantially as described above and in particular with reference to the preparation of silicate III in the example. 8. Crystalline aluminum silicates prepared according to a method as described in claim 7. 8002416 -15- Process for carrying out catalytic processes, characterized in that a catalyst is used which contains a crystalline aluminum silicate according to claim 8. 10. Process according to claim 9, characterized in that the crystalline aluminum silicate is used as a catalyst in the preparation of an aromatic hydrocarbon mixture from a mono-olefin or from a hydrocarbon mixture containing more than 75% by weight of C 10-mono-olefins. exists. Process according to claim 10, characterized in that the feed used is a C 1 or mono-olefin or a hydrocarbon mixture consisting essentially of one or more of these mono-olefins. 12. Process according to claim 11, characterized in that the feed used is a mainly hydrocarbon mixture consisting of and / or mono-olefins, which is obtained as a by-product in the catalytic or thermal cracking of hydrocarbons, in particular in the case of thermal cracking of hydrocarbons to prepare ethylene. 13. A method according to any one of claims 10-12, characterized in that it is carried out at a temperature of 300-550 ° C, a pressure of 3-20 bar and a spatial flow rate of 1-20 µg. "1. Method according to claim 13>, characterized in that it is carried out at a temperature of 350-500 ° C, a pressure of 5-15 bar and a spatial flow rate of 2-10 µg "1hr" 1. 15. A method according to any one of claims 10-14, characterized in that it is carried out using a crystalline aluminum silicate for which 0.0075 ^. m ^ 0.0030 and having a crystallite size of at most 500 nm. 80024 16 -16- 16. Process according to claim 9, characterized in that the crystalline aluminum silicate is used as a catalyst component in the preparation of an aromatic hydrocarbon mixture from an E 2 / CO mixture. Process according to claim 16, characterized in that an E 2 / CO mixture having an E 2 / CO molar ratio below 1.0 is contacted with a mixture of two catalysts, one of which has the capacity to to catalyze the conversion of one E 2 / CO mixture into acyclic oxygenated hydrocarbons and the other is the crystalline aluminum silicate. 18. Process according to claim 17, characterized in that the Hg / CO mixture is prepared by steam gasification of coal at a temperature of 900-1500 ° C and a pressure of 10-50 bar. 19. Process according to claim 17 or 18, characterized in that the catalyst having the ability to convert an E 2 / CO mixture to acyclic oxygen-containing hydrocarbons and a catalyst capable of converting an H 2 / C0 mixture to convert mainly to methanol and / or dimethyl ether. Process according to claim 19, characterized in that a catalyst is used which contains the metal combination Zn-Cr. 21. Process according to any one of claims 16-20, characterized in that it is carried out at a temperature of 200-500 ° C, a pressure of 1-150 bar and a spatial throughput of 50-5000 NI gas / 1 catalyst / hour. Process according to claim 21, characterized in that it is carried out at a temperature of 250-450 ° C, a pressure of 5-100 bar and a spatial flow rate of 300-3000 nl gas / 1 catalyst / hour. 8002416 -17- 23. Process according to any one of claims 17-22, characterized in that it is used as the first step of a two-step process for the preparation of an aromatic hydrocarbon mixture from an I / O / CO mixture 5 with an H 2 / CO mol Ratio below 1.0, of the reaction product from the first step, at least the C2 ”fraction being contacted in a second step with a catalyst containing one or more metal components with catalytic activity for the conversion of a 10 Hg / CO mixture to acyclic hydrocarbons, which metal components are selected from the group consisting of cobalt, nickel and ruthenium, with the proviso that if the feed for the second step has an II / CO molar ratio of less than 1.5, water will be added to this feed is added and that in the second step a bi-functional catalyst is used which in addition to the metal components with catalytic activity for the conversion of a Hg / CO mixture into acyclic hydrocarbons, in addition, contains one or more metal components 20 with catalytic activity for the conversion of an HgO / CO mixture into an H 2 / CO 2 mixture. 24. A process for carrying out catalytic processes, in particular the preparation of aromatic hydrocarbon mixtures, essentially as described above and in particular with reference to experiment 3 in the example. 25. Aromatic hydrocarbon mixtures prepared by a method as described in claim 24. 8002416