DK167867B1 - PROCEDURE FOR THE PREPARATION OF AN ALUMINUM DRILL-SILICATE CATALYST - Google Patents

Description

DK 167867 B1

The present invention relates to a process for producing an aluminum boron silicate catalyst. In particular, the invention relates to Al-B-Si catalysts which can be used for alkylation of aromatic hydrocarbons.

The use of crystalline silicate compounds for the alkylation of aromatic hydrocarbons is known. For example, U.S. Patent No. 4,283,306 discloses a crystalline silicate for methylation of toluene to form the paraxylene.

Crystalline aluminum silicate catalysts for the alkylation of aromatic hydrocarbons are also known. U.S. Patent No. 2,904,697 relates to an alkylation process using metallic aluminum silicate. US Patent No. 3,251,897 describes aluminum silicates of the x and y types and especially those which, as a cation, have either hydrogen or a rare earth metal. In several other patents, aluminum silicates are described which have high selectivity to form para-substituted aromatics: e.g.

According to U.S. Patent No. 4,117,024, crystalline aluminum silicates have been modified using solutions of difficultly reducible oxides such as antimony, phosphorus or boron.

In several patents, alkylation processes have been described. Steam phase alkylation with high silicon aluminum silicate catalysts generally leads to high conversion rates. The useful life of silicate catalysts is quite long, and in many cases 25 the required pressure is low, making such processes economically attractive. Examples of vapor phase alkylation include U.S. Patent Nos. 3,751,504 and 3,751,506.

The present invention relates to novel zeolite catalysts containing silicon, aluminum and boron in which pores and passages 30 are not blocked by atoms, molecules or ions, for example by sulfate or chloride ions. Hereby, the movement of reagents within the silicate is hindered, leading to a high degree of conversion in the alkylation process and to a high selectivity.

DK 167867 B1 2

The present invention relates to a process for the preparation of such aluminum boron silicate catalysts which are particularly suitable for use in the alkylation of aromatic hydrocarbons and which provide high degree of conversion and / or high selectivity in the production of para-substituted hydrocarbons.

According to the invention, there is thus provided a process for the preparation of aluminum boron silicate catalysts in which the molar ratio SiC> 2 / Al2 O3 is in the range 10-150, preferably in the range 10-60, and the molar ratio Al2O3 / B2O3 is in the range 2-200. , preferably in the range 19-200. The molecular formula of these catalysts can be expressed as follows: 0.8-1.2 M 2 O: Al 2 O 3: 0.005-0.1 B 2 O 3: 10150 SiO 2: x H cation containing nitrogen, and x is in the range of 0-60.

The process is characterized in that a reaction mixture comprising a cation containing organic nitrogen obtained from pyrrolidine or tetraethyl, tetrapropyl, or tetrabutylammonium chloride or a mixture thereof, an alkali metal oxide or mixtures thereof, aluminum oxide, boron and silicon and water, 20 is heated in a closed reaction vessel, first to an initial temperature of at least 175 ° C and at most 220 ° G, and then to a lower reaction temperature which is in the range of 100-190 ° C, preferably in the range of 130-170 ° C. to form aluminum-boron silicate catalyst.

25 M can also be a mixture of alkali metal cations, preferably of sodium and potassium cations. The organic cation containing nitrogen may be an ammonium cation, for example a tetraethyl, tetrapropyl or tetrabutylammonium cation. The organic cation containing nitrogen may also be a cation derived from pyrrolidine.

In the preparation of an aluminum-boron-silicate catalyst of the present invention, a reaction mixture first containing a cation of organic nitrogen, alkali metal oxide, oxide, aluminum, boron and silicon and water in a reaction vessel is first heated. Depending on the circumstances, the required pressure of the reaction is in the range 1-15 bar. A higher starting temperature is selected in the range between 175 and 220 ° C, preferably in the range between 190 and 5,200 ° C. When a higher starting temperature is used, a homogeneous reaction mixture is obtained in a shorter time and the formation of crystals starts earlier. The heating time at the starting temperature is preferably between 30 minutes and 6 hours. Heating is continued at a lower reaction temperature in the range of 100-190 ° C. The heating time at the lower temperature is preferably selected in the range between 1 and 6 days.

It is possible in a catalyst according to the invention to exchange ions with other cations using known ion exchange technique. A recommended practice is to replace a hydrogen ion with an alkali metal cation, which increases the catalyst activity by aromatic alkylation.

In one embodiment of the invention, the catalyst prepared in the manner described above can be further modified using compounds containing boron to form a catalyst which, in alkylation, produces high yield para-substituted aromatics.

The modification can be carried out by mixing a catalyst prepared as above and boric acid, boric oxide or mixtures thereof in the dry state. Then the mixture is heated to 300-700 ° C, preferably 550-600 ° C, with occasional mixing. The warm-up time is not critical. When a catalyst modified in this way is used, para-substituted aromatics are obtained in high yield by alkylation.

Of course, the catalysts of the invention can be used either as such or in combination with conventional carriers and binders.

30 Al-B-S1 catalysts prepared by the process of the invention can be used in alkylation. In this process, various hydrocarbons such as benzenes, naphthanes, anthracenes and substituted derivatives thereof such as toluene and ethylbenzene can be alkylated.

DK 167867 B1 4

As alkylating agents in the process of the invention, several compounds may be used which contain at least one reactive alkyl radical, for example ethylene, propylene, formaldehyde, alkyl halides and alcohols.

The process conditions during alkylation, e.g., temperature, pressure and flow rate, are generally critical and depend on the starting materials and are therefore described in more detail below.

The alkylation process of the invention is carried out in vapor phase. As a reaction vessel, either a fluid bed reactor or a stationary bed reactor is used. Aluminum boron silicate for use as a catalyst occurs in hydrogen form. The reaction pressure can vary depending on the type of reactor, catalyst amount, catalyst particle size and other factors, and is between atmospheric pressure and 10 bar. The temperature can vary in the range of 200 to 700 ° C, preferably in the range of 300 to 600 ° C. Before contacting the input materials with the catalyst, they are heated to the desired reaction temperature. The flow rate used depends on the reactants and the reactor and is generally in the range between 1 and 100 hours (WHSV). The mole ratio of aromatic carbohydrate to alkylating agent may be in the range of 0.5 to 20. The recommended mole ratio for monoalkylation is In addition, a diluent gas, e.g., nitrogen and / or coke formation agents, e.g., hydrogen, may be used.

The hot product stream from the reactor is cooled to room temperature or a temperature below, after which the liquid and gas phases are separated. Gases that have not reacted can be stored and recycled. The liquid components which have not participated in the reaction, for example toluene, are separated from the product mixture, for example by distillation, and reused. In the examples below, the preparation of the catalyst 30 according to the invention is further described.

EXAMPLE 1 In this example, an aluminum boron silicate catalyst having the identification BOA-1 is prepared.

Dissolve 4.05 g of NaOH in 165 ml of water. 87.85 g of tetrapropylammonium bromide are added to the solution at room temperature to give solution A.

Solution B is prepared by dissolving 4.2 g of NaA102 (containing 28.4 wt% Na2 O, 46.8 wt% Al2 O3 and 24.8 wt% H2 O) and 0.19 g Na2B40-7 x 10 H 2 O (containing 16.3 wt% Na2 O, 36.5 wt% B 2 O 3 and 47.2 wt% H 2 O in 405.5 g water. Solution A and B are then mixed together and passed into an autoclave in which an additional 34.2 g SiO 2 (silica gel) and 82.8 g water are placed. The composition of the mixture is as follows: 0.02 moles Na 2 O, 0.02 moles Al 2 O 3, 0.001 moles B 2 O 3, 0.57 moles SiO 2, 0.33 moles N (CH 3 CH 2 CH 2) 4 and 36.3 moles of water.

The mixture is heated to 200 ° C for 2 hours and then to 160 ° C for 3 days. After cooling to room temperature, the crystalline product is filtered and washed with 2 liters of water. The crystals are dried at 100 ° C and then calcined at 530 ° C for 18 hours.

The catalyst thus obtained is contacted with a 5% by weight solution of ammonium chloride at 80 ° C for 1 1/2 hours. The procedure is repeated three times, each time using 15 ml of solution per ml. g catalyst. The product is filtered and washed chloride-free with water.

Drying is carried out at 100 ° C and after drying calcination in 25 air overnight at 530 ° C to give the hydrogen form of catalyst BOA-1.

The surface area of the catalyst is 345 m 2 / g.

EXAMPLE 2

This example describes the synthesis of the aluminum boron silicate catalyst BOA-2.

The following ingredients are mixed in water (265 g): 6.5 g NaAlO 2 (containing 28.4 wt% Na 2 O, 46.8 wt% Al 2 O 3 and 24.8 wt% H 2 O) and 0.29 g Na 2 B 40 y (containing 16.3 wt% Na2O, 36.5% by weight B2O3 and 47.2% by weight H2O). To the mixture is added 2.78 g of NaOH and thoroughly mixed. The mixture is placed in an autoclave and 900 g of H2O, 395 g of S1O2 and 141 g of pyrrolidine are added.

The mixture is heated to 200 ° C for 3 hours and then to 165 ° C for 3 days, after which it is cooled to room temperature over 15 hours. The crystals are filtered and washed with 3 liters of water. Further preparation of the catalyst BOA-2 is carried out as described in Example 1 with the difference that temperatures above 100 ° C are used and nitrogen atmosphere is used instead of air.

EXAMPLE 3

According to this example, modification with boron compounds of the catalysts B0A-1 and BOA-2 is performed.

5 g of the catalysts 20 prepared as described in Examples 1 and 2 are mixed with 0.5 g of B2O3 and then heated in air to 550 ° C for 1 hour. During heating, the components are mixed five times. After this treatment, the modified catalysts are ready for use.

Toluene ethylation tests are performed using the unmodified and modified catalysts BQA-1 and BOA-2 prepared as described in Examples 1-3.

EXAMPLES 4-8 In these examples, a fluid bed reactor is used in which 5 g of the unmodified B0A-1 catalyst from Example 1 is introduced. In all of the examples, the reaction temperature is 600 ° C and the feed rate and molar ratio of toluene to ethylene are varied. The results are given in Table I below.

TABLE I

5 Eczema Temp.Tol. WHSV toluene-p-ethyltol. ethyltol.

pel ratur mole hour "conversion per total per aro- ° C ethyl etol. mat%% 10 4 600 0.8 24 25 26 67 5 600 1.1 22 26 24 85 6 600 1.9 20 30 EXAMPLES 9-13 In the following examples, 5 g of modified catalyst BOA-1 from Example 3 is introduced into a fluidized bed reactor. listed in Table II.

TABLE II

Eczema Temp- tol.:eth. WHSV toluene-p-ethyltol. ethyltol. pel ratur mole hour "* * converted per total by arole ethyltol. mat%%% 25 9 520 1.9 61 12 90 91 10 520 2.3 59 13 90 100 II 520 1.4 32 22 84 95 12 520 1.4 37 22 90 97 30 13 470 1.2 33 17 93 100 DK 167867 B1 8

No o-ethyltoluene is formed.

EXAMPLES 14-15 In these examples, 5 g of the catalyst BOA-1 from Example 1 is used as a catalyst in a stationary bed reactor. The results are given in Table III.

TABLE III

Eczema Temp- tol.:eth. WHSV toluene-p-ethyltol. ethyltol.

pel ratur mols time'conversion. total pr. ethyl acetate. mat 10%%% 14,500 2.1 25 6 74 92 15 600 2.1 25 7 72 98 15 EXAMPLES 16-18 In the examples below, 5 g of unmodified catalyst BOA-2 from Example 2 is introduced into a fluid bed reactor. The reaction temperature is 600 ° C. The results are given in Table IV.

TABLE IV

20 Eczema Temp.Tol. WHSV toluene-p-ethyltol. ethyltol.

pel ratur mole hour '^ · convert. total pr. ethyl acetate. mat%%% 25 16 600 1.1 22 28 27 84 17 600 1.5 42 22 39 87 18 600 1.9 50 17 53 78 DK 167867 B1 9 EXAMPLES 19-21 5 g of the catalyst BOA prepared according to Example 3 -2 is modified as described in Example 3, and for the alkylation tests a fluid bed reactor and a reaction temperature of 600 ° C are used. The results are given in Table V below.

TABLE V

Eczema Temp- tol.:eth. WHSV toluene-p-ethyltol. ethyltol.

pel ratur mole hour "conversion per total per aroleC ethyl etol. mat 10%%% 19 600 2.3 15 2 92 70 20 600 1.9 20 2 92 65 21 600 1.5 42 2 89 EXAMPLE 22

Methylation of toluene is done with methanol using toluene and methanol in a 2: 1 molar ratio. The catalyst is BOA-2 from Example 2, modified as described in Example 3. The reaction is carried out in a stationary bed reactor and at a temperature of 500 ° C.

The yield is 1% pure isomer-free p-xylene.

Claims (3)

A process for preparing an aluminum boron silicate catalyst having the composition: 0.8-1.2 M 2 O: Al 2 O 3: 0.005-0.1 B 2 O 3: 10150 SiO 2: x H 2 O where M is selected from the group consisting of an alkali metal cation or an organic cation containing nitrogen, and x is in the range of 0-60, by heating a reaction mixture comprising a cation containing organic nitrogen obtained from pyrrolidine or tetraethyl, tetrapropyl, or tetrabutylammonium chloride or a mixture thereof, an alkali metal oxide or mixtures thereof, aluminum oxide, boron and silicon and water, in a closed reaction vessel, characterized in that said reaction mixture is first heated to an initial temperature of at least 175 ° C and not more than 220 ° G, and then to a lower reaction temperature which is within In the range of 100-190 ° C, preferably in the range 130-170 ° C, to form the aluminum boron silicate catalyst. Process according to claim 1, characterized in that the heating time at the initial temperature is between 30 minutes and 6 hours. 20 Process according to claim 1 or 2, characterized in that the heating time at the lower temperature is at least 8 hours and preferably 1-6 days. Process according to any one of claims 1 to 3, characterized in that the cation containing organic nitrogen is completely or partially replaced with protons to produce an catalyst in the form of an acid.