CA1233459A

CA1233459A - Procedure for producing zeolite catalysts, and alkylation process

Info

Publication number: CA1233459A
Application number: CA000465532A
Authority: CA
Inventors: Peter Idelman
Original assignee: Neste Oyj
Current assignee: Neste Oyj
Priority date: 1983-10-17
Filing date: 1984-10-16
Publication date: 1988-03-01
Also published as: AT399107B; JPS61500951A; SE453965B; DK272885A; DK272885D0; DK167867B1; CH668714A5; FI76005B; GB8513696D0; IT8423170A0; DE3490487C2; SE8502661L; FI76005C; WO1985001675A1; GB2169271B; IT1196297B; BE900830A; GB2169271A; FI833788A; FR2553301A1

Abstract

ABSTRACT OF THE DISCLOSURE

The present invention provides a process for producing an aluminium-boron-silicate catalyst with the composition 0.8-1.2 M2/n O : A12O3 : 0.005-0.01 B2O3 :
10-150 SiO2 : x H2O. In the process, a reaction mixture which contains a cation with organic nitrogen, an alkali metal oxide or a mixture thereof, aluminium oxide, boron oxide and silicon dioxide and water, is heated in a closed reaction vessel initially at a higher temperature and there-after at a lower temperature for producing an aluminium-boron-silicate catalyst. The cation containing organic nitrogen is suitably derived from pyrrolidine or tetraethyl, tetrapropyl or tetrabutyl ammonium chloride or a mixture thereof. The catalysts are useful in the alkylating of aromatic hydrocarbons.

Description

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The present invention relates to a process for producing zeolite catalysts. In particular, the invention relates to Al-s-Si catalysts which are suitable for alkyl-ating aromatic hydrocarbons. The presen-t invention also relates to a process for alkylating aromatlc hydrocarbons using said catalysts.

The use of crystalline silicat.e compounds in alkylating aromatic hydrocarbons is known. For instance, U.S. Patent No. 4,283,306, discloses a crystalline silicate for methylating toluene to produce paraxylene. Also cry-stalline aluminium silicate catalysts for alkylating aromatic hydrocarbons are known. U.S. Patent No. 2,904,697 discloses an alkylation process in which metallic aluminium silicate is used. U.S. Patent No. 3,251,897 descrlbes aluminium silicates of x and y type and in particular those which have as their cation either hydrogen or a rare earth metal. In several other U.S. patents such as U.S. Patents Nos.
3,702,886 ; 3,965,207; ~,100,217 and 4,117,024 aluminium silicates are described which have a high selectivity to form parasubstitu-ted aromatics.

In U.S. Patent No. 4,117,024, crystalline aluminium silicates are modified using solutions of difficultly reduc1ble oxides such as antimony, phosphorus or boron.
Alkylation processes have been described in numerous patents.
Alkylation in the vapour phase with aluminium silicate catalysts rich in silicon generally produces high conversion.
The useful life of silicate catalysts is rather long, and in many instances the required pressure is low, which makes said processes economically attrac-tive. Instances of vapour phase alk~lation disclosures are inter alia U.S. Patents Nos. 3,751,504 and 3,751,506.

The present invention provides novel zeolite catalysts containing silicon, aluminium and boron in which ~33~5~

the pores and passages are not clogged by atoms, molecules or ions, for lnstance sulphate or chlorlde ions. Thus, the movement of reagents within the silicate is unimpedea, resulting in high conversions in the alkylation process and in high selectivity.

The present invention also provides a process for pro-ducing such aluminium-boron-silicate catalysts which are particu-larly well suited for alkylat~ng aromatic hydrocarbons and which yield a hiyh conversion and/or high selectivity for producing parasubstituted hydrocarbons. The invention al50 provides a pro cess for alkylating aromatic hydrocarbons using said catalysts.

Thus, according to the invention, a process is provided producing aluminium-boron-silicate catalysts in which the SiO2/
15 A12O3 molar proportion it in the range 10-150, preferably in the range 10-60, and the A1203/B203 molar proportion is in the range

2~200, preferably in the range 19-200 and -the molecular formula may be expressed as follows:

20 0.8-1.2 M2/ 0 A123 0.005-0.1 B203 10-150 SiO~ : x H20 where M is at least one cation with valence n, and x is ih the range 0-60 in which process a reaction mixture, which comprises a cation containiny organic nitrogen and derived from pyrrolidine 1 25 or from tetraethyl, tetrapropyl or tetrabutyl ammonium chloride, j or from a mixture of these, an alkali metal oxide or a mixture of such, aluminlum oxide, boron oxide and silicon dioxide and water in a closed reaction vessel, in which said reaction solution is heated at first at a higher starting temperature, which is at 30 least 165C and not higher than 220C, and thereafter at a lower reaction temperature, which is in the range 100-190C, for form-ing the aluminium-boron-silicate catalyst.

\ - 2 -~233~9 In the above formula of the catalyst, M is at least one catlon with valence n, M may also be a mixture of alkali metal cations, preferably of sodium and potassium cations. The organic cation containing nitrog2n may be an , .~ ,.

- 2a -I' , ...

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an ammonium cation, such as a tetraethyl, tetrapropyl or tetrabutyl ammonium cation. the organic cation containing nitrogen may also be derived from pyrrolidine. Thus the cation containing organic nitrogen is derived from pyrroli-dine or Erom tetraethyl, tetrapropyl or tetrabutyl ammoniumchloride, or from a mixture thereof.

When producing a zeolite catalyst according to the present invention, a reactive mixture containing a cation with organic nitrogen alkali metal oxide, oxide of alumin-ium, boron and silicon and water is first heated in a reac-tion vessel. Depending on the conditions, the pressuxe required in the reaction varies in the range 1-15 bars. A
higher initial temperature is in the range 175-220C, pre-ferably in the range 190-200C. When a higher initial tem-perature is used, a homogeneous reaction mixture is obtained in shorter time and formation of crystals begins quicker.
The heating time at the initial temperature is preferably between 30 minutes and 6 hours. Heating is continued at the lower reaetion temperature in the range 100-190C. The heat-ing time at the lower temperature is at least 8 hours and preferably in the range 1-6 days.

It is possible in a catalyst according to the in-vention to exchange ions with other cations, using conven-tional exchange techniques. A recommendable practice is to exchange an alkali metal ion for a hydrogen ion, which in-creases the activity of the catalyst in aromatic alkylation.

According to one embodiment of the invention, the catalyst produced may be further modified using compounds containing boron, whereby a catalyst is produced which in alkylation produces parasubstituted aromatics in high yield.
The embodiment may be accomplished by mixing a catalyst produeed as described above and borie aeid, boron oxide or their mixture in dry state. Thereafter the mixture is heated ~L~33~
at 300-700 C, preferably at 550-600C, with periodic mixing.
The heating time is not critical. Suitably the quantity of boron compound used is 0.1-30% by weight. When a catalyst modified in this manner is used, parasubstituted aromatics are obtained at high yield in the alkylation.

The catalysts of the invention may, of course, be used either as such or combined with conventional carriers and bonding agents.

The present invention also provides an alkylation process in which Al-B-Si catalysts produced by the process of the invention are utilized. With the process, various hydrocarbons such as benzenes, naphthalenes, anthracenes and substituted derivatives, such as toluene and ethylben-zene, can by alkylated. The alkylating agent used in the process of the invention includes numerous compounds which have at least one reactive alkyl radical, such as ethylene, propylene, formaldehyde, alkyl halides and alcohols. The process conditions in alkylation, such as the temperature, pressure and flow rate, are generally critical, depending on the starting materials, and they are described more in detail in the following.

The alkylation process of the invention is effec-ted in the vapour phase. The reactor is either a fluidizedbed reactor or a stationary bed reactor. The aluminium-boron-silicate catalyst is present in its hydrogen form.
The reactor pressure may vary, depending on reactor type, catalyst quantity, ca-talyst particle size and other factors, from atmospheric pressure up to 10 bars. The temperature may vary in the range 200-700C, preferably in the range 300-600C. Prior to contacting the reactant materials with the catalyst, they are heated to desired reaction tempera-ture. The flow rate that is used depends on the reactants, the reactor, and generally is in the range 1-100 hr 1 (WHSV).

~L233~9 The molar proportion of aromatic hydrocarbon and alkylation agent may vary in the range 0.5-20. The molar proportion recommended in monoalkylation is 1-4. In addition, a dilu-tion gas may be used, e.g. nitrogen and/or agents reducing the co]ce formation, for instance hydrogen.

The hot product flow emerging from the reactor is cooled to room temeprature or to a lower -temperature, whereafter the liquid and gas phases are separated. The gases that have not reacted may be stored and reused. The liquid components which have not participated in the reaction, such as toluene, are separated from the product mixture for instance by distillation and reused.

In the following Examples, the production of the catalyst of the invention is described more in detail:

Example 1 The aluminium-boron-silicate catalyst carrying the identification BOA-l is produced.

4.05 g NaOH were dissolved in 165 ml water. To the solution, 87.85 g tetrapropylammonium bromide were added at room temperature, thereby obtaining solution A.

Solution B was prepared by dissolving 4.2 g NaAlO2 (containing 28.4% by weight Na 2 46.8% A12O3, and 24.8% by weight H2O and 0.19 g Na2B4O7 x 10 H2O (containing 16.3% by weight Na2O, 36.5% by weight B2O3 and 47.2% by weight H2O) in 405.5 g H2O. Solutions A and B were thereafter mixed to-gether and introduced in an autoclave, in which in addition 34.2 g SiO2 (silicagel) and 82.8 g water were placed. The composition of the mixture was as follows: 0.02 mol Na 0.02 mol A12O3, 0~001 mol B2O3, 0.57 mol SiO2, 0.33 mol N(CH3CH2CH2)4 and 36.3 mol water.

~L~33~9 The mlxture was heated at 200C for two hours, and thereafter at 160C temperature for three days. Subsequent to cooling to room temperature, the craystalline product was filtered and washed with 2 litres of water. The crystals were dried at 100C and thereafter calcined at 530C for 18 hours.

The catalyst thus obtained was contacted with a 5% by weight solution of ammonium chloride at 30 C for 1.5 hours. The procedure was repeated three times, using each time 15 ml solution per one gramme of catalyst. The product was filtered and washed with water until chloride-free. Dry-ing was carried at 100C, and after drying calcination was performed in air at 530C overnight, whereby the hydrogen form of the catalyst BOA-l was obtained.

- 5a -

3~

The surface area of the catalyst was 345 m2/g.

example 2 Thls Example concerns the synthesis of the alumlnium-boron-silicate catalyst BOA-2.

The following ingredients were mixed in water ~265 g):
6.5 g NaA102 (containing 28O4% by weight Na2O, 46.8~ by welght A12O3 and 24.8% by weight H2O) and 0.29 g Na2B407 (containiny 16.3~ by weight Na2O, 36.5% by weight B2O3 and 47.2% by welght H2O). To the mixture were added 2.78 g NaOH, and it was well mixed. The mixture was placed in an autoclave, and 900 g H2O, 395 g SiO2 and 141 g pyrrolidine were added. The mixture was heated at 200C for three hours, and thereafter at 165C for three days, whereafter it was cooled to room temperature during 15 hours. The crystals were filtered and washed with water (3 litres). The further preparation of the catalyst BOA-l took place as in Example 1, with the difference that at temperatures higher than 100C a nitrogen atmosphere was used instead of air.
Example 3 In this Example, modification with boric compounds of the catalysts BOA-l and sOA-2 is carried out.
To the catalysts prepared in Examples 1 and 2 (5 g thereof) were admlxed 0.5 g B2O3, followed by heating in air at 550C for one hour. During the heating, the components were mixed five times. After this treatment, the modified catalysts were ready to be used.

Toluene ethylating tests were performed using the unmodified and modified catalysts BOA-l and BO~-2 produced in Examples 1-3-Examples 4-8 In these Examples a fluidized bed reactor was used in which 5 g of the unmodlfied catalyst BOA-l of Example 1 has been introduced. In all Examples, the reaction temperature was 600C, and the input rate and the toluene/ethylene molar proportion were varied. The results are presented in Table l below.

Table l 10 Exam- TOemp. tol.-eth. WHSy tol.conv. p-ethyltol ethyltol ples C moles hr~ per total per aro-ethytol %_ matics %
600 0.8 2~ 25 2~ 67 600 l.l 22 26 2~ 85 6 600 1.9 20 30 27 91 7 600 1.4 38 13 45 90 8 600 l.9 50 9 58 96 J

Examples 9-l3 In the following Examples 5 g of the modified catalyst BOA-l of Example 3 was introduced in a fluidized bed reactor.
The results are presented in Table II.

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Table II

Exam- Kemp. tol:eth. WHS~ tol.conv. p-ethyltol. ethyltol ples C moles hr %per total per aro-ethytol. % matics %
.
9 520 1.9 61, 12 90 91 520 2.3 59 13 90 100 11 520 1.4 32 22 84 95 12 52~ 37 22 go 97 13 470 1.2 33 17 93 1~0 No o-ethyltoluene was formed.

Examples 14 15 In these examples, the catalyst BOA-l (5 g) of Example 1 was used for catalyst in a stationary bed reactor. The results are presented in Table III.

Tabl_ III
T .~
Exam- Kemp. tol .: eth. WHSy tol . conv . p-ethyltol. etnyltol.
ples C moles hr %per total per aro-_ ethytol. % matics %
14 500 2.1 25 6 74 92 600 2.1 25 7 72 98 E _ ples 16-18 In the following Examples, 5 g of the unmodified catalyst BOA-2 of Example 2 were introduced in a fluidized bed reactors. The reaction temperature used was 600C. The results are presented in Table IV.

Table IV
Exam- Kemp. tol.:eth. WHSy tol.conv~ p-ethyltol. ethyltol ples C moles hr % per total per aro-_ ethytol. matlcs S 16 600 1.1 22 28 27 84 17 600 1.5 42 22 39 87 18 600 1.9 50 17 53 78 .

Examples 19-21 5 g of the catalyst BOA-2 of Example 3 were modlfied as in Example 3, and in the alkylatlon tests a fluidized bed reactor and 600C reaction temperature were used. The results are presented in Table v.

Table V
.
Exam- Temp. tol.:eth. WHsy tol.conv. p-ethyltol. ethyltol.
ples UC moles hr~ % per total per aro-ethvtol. % matics %
19 600 2.3 j 15 2 92 70 600 1.9 20 2 92 65 21 600 1.5 42 2 89 30 Example 22 Methylation of toluene was accomplished with methanol using toluene/methanol molar proportion 2:1. The catalyst was BOA-2 of example 2, modified as in Example 3. The reaction was carried out in a stationary bed reactor, at 500C. The yield was l of pure isomer-free p-xylene.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. In a process for preparing an aluminium-boron-sili-cate catalyst of the composition 0.8-1.2 M2/nO : Al2O3 : 0.005-0.01 B2O3 : 10-150 SiO2 : X H2O

where M is at least one cation with the valence n, and x is in the range 0-60, by heating a reaction mixture which comprises a cation containing organic nitrogen and derived from pyrrolidine or from tetraethyl, tetrapropyl or tetrabutyl ammonium chloride, or from a mixture of these, an alkali metal oxide or a mixture of of such, aluminium oxide, boron oxide and silicon dioxide and water in a closed reaction vessel, the improvement in which said reaction solution is heated at first at a higher starting temper-ature, which is at least 165°C and not higher than 220°C, and thereafter at a lower reaction temperature, which is in the range 100-190°C, for forming the aluminium-boron-silicate catalyst.

2. A process according to claim 1, in which the heat-ing time at the lower reaction temperature is at least 8 hours.

3. A process according to claim 1, in which the heat-ing time at the lower reaction temperature is 1 to 6 days.

4. A process according to claim 1, 2 or 3, in which the heating time at the starting temperature is in the range 30 minutes to 6 hours.

5. A process according to claim 1, 2 or 3, in which the cation containing organic nitrogen is totally or partially substituted with proton in order to form a catalyst having the form of an acid.

6. A process according to claim l, 2 or 3, in which the lower reaction temperature is in the range 130 to 170°C.