RU2201802C2 - Molded ionite catalyst preparation method - Google Patents

Abstract

FIELD: organic synthesis catalysts. SUBSTANCE: catalyst is prepared by mixing of styrene/divinylbenzene-based copolymer and thermoplastic material, extrusion-mediated molding of resulting mixture, sulfurization, washing, and drying, aforesaid copolymer being, in particular, macroporous styrene/divinylbenzene copolymer mixed with gel-like terpolymer of styrene, divinylbenzene, and a polar monomer at weight ratio between 1:4 and 4:1. Preferable particle size of copolymers ranged between 30 and 160 mcm. EFFECT: increased catalytic activity. 2 cl, 1 tbl, 5 ex

Description

 The invention relates to the production of ionized molded catalysts used in olefin hydration, esterification, dehydration of alcohols, decomposition of esters and other processes catalyzed by ion exchangers.

 A known method of preparing an ionic molded catalyst using crushed synthetic resin is a copolymer of styrene with divinylbenzene [USSR copyright certificate 1075499, 01 J 31/10, 1995, Bull. 6]. According to the method, the styrene copolymer is molded with a hermoplastic material by extrusion and the obtained granules with a diameter of 4-5 mm and a length of 5-10 mm are sulfonated with sulfuric acid.

 This method involves the mandatory preliminary swelling of the molded copolymer in dichloroethane before the stage of sulfonation, which complicates the production of the catalyst.

Closest to the claimed method is a method of preparing an ionic molded catalyst for organic synthesis by mixing a copolymer of styrene and divinylbenzene with a thermoplastic material [RF patent 1804003, 01 J 31/10, 1995, Bull. 8]. The method includes mixing a copolymer of styrene and divinylbenzene with a thermoplastic material; extrusion of the resulting mixture at a temperature of 70-160 ^o With subsequent sulfonation of the resulting product, washing and drying. As the copolymer, a ternary copolymer of styrene, divinylbenzene and a monomer containing a functional group, for example, acrylic acid nitrile (NAC) or methyl methacrylate, can be used. In this case, sulfonation is carried out without preliminary swelling in dichloroethane, and the resulting catalyst has a total static exchange capacity (PSOE) of 3.6-3.9 mEq / g and activity in the process of decomposition of tert-butyl alcohol (TBS) - an azeotrope of 75%.

 The present invention is directed to increasing the activity of the catalyst.

 It is known that the catalytic activity of sulfocationionites based on macroporous copolymers, as a rule, is significantly higher than the activity of gel sulfocationites [N. G. Polyansky "Catalysis by ion exchangers", M., Chemistry, 1973, pp. 54-56].

The catalyst activity could be increased if, instead of a ternary copolymer of styrene, divinylbenzene and a polar monomer having a gel structure, a double copolymer of styrene with divinylbenzene having a macroporous structure was used. In this case, sulfonation of the molded copolymer could also be carried out without preliminary swelling in the solvent. It is known that the specific surface of gel copolymers of styrene with divinylbenzene and ion exchangers based on them varies depending on the particle size from 0.1 to 0.5 m ² / g, while the specific surface of macroporous copolymers of styrene with divinyl benzene and ion exchangers based on them depending on the composition and method of preparation in the unmilled state (granulation 0.6-1 mm) is 5 - 40 m ² . When grinding, the specific surface increases (B.N. Lasporin, A.I. Yuzhin, L.A. Strelkov. Porous ion-exchange resins in the collection. Synthesis and properties of ion-exchange materials "Science", Moscow, 1968, pp. 34-38) . Due to the developed inner surface of the milled macroporous copolymer, it is impossible to obtain a molded product from this copolymer and thermoplastic, for example, polyethylene, at a mass ratio of 70:30, as was proposed in [1] and [2]. To facilitate molding, it is necessary to increase the amount of thermoplastic in the molding mixture, which inevitably affects the quality of the obtained catalyst, i.e. It is not possible to obtain a catalyst with increased activity in this way.

 To achieve this result, we propose a method for preparing an ionized molded catalyst for organic synthesis by mixing a copolymer based on styrene and divinylbenzene with a thermoplastic polymer material, molding the resulting mixture by extrusion, followed by sulfonation, washing and drying, which consists in the fact that as a copolymer based on styrene and divinylbenzene use a double macroporous styrene-divinylbenzene copolymer mixed with a triple gel styrene copolymer, divi ylbenzene and a polar monomer in a weight ratio of from 1: 4 to 4: 1.

 It is most preferable to use these copolymers with a particle size of 30-160 microns.

The present invention used double macroporous styrene divinylbenzene copolymers of Purolite company with a specific surface in the unmilled state from 2.5 m ² / g to 30 m ² / g and triple gel copolymers of styrene, divinylbenzene and acrylic acid nitrile (NAC) or methyl methacrylate with specific surface in the unmilled state ~ 0.1 m ² / g.

 A mixture of a double macroporous and a triple copolymer with a thermoplastic is successfully formed at a mass ratio of copolymer: thermoplast of 70:30.

 After sulfonation of the formed granules with concentrated sulfuric acid (diameter 5-6 mm, length 5-10 mm), a catalyst is obtained having a PSOE of 3.8-4.0 mEq / g and a catalytic activity in the dehydration of TBS - an azeotrope of 80-85%.

Often, catalytic processes in tubular reactors require a catalyst with a particle size of 2 • 2 mm or less. The proposed method allows to obtain a catalyst with particles of this size, while the activity of the catalyst increases significantly, for example, in the process of dehydration of the TBS azeotrope is 90-93%. Macroporous sulfocationionites, for example, KU-23 with a particle size of 0.3-1.25 mm, have the same activity in this process. Molded ion-exchange catalysts with a small granule size (diameter 1.5-3 mm, length 2-5 mm) with equal catalytic activity exceed standard cation exchangers by the convenience of working with them, namely:
- have less hydrodynamic resistance;
- do not undergo cracking, abrasion and destruction during operation;
- no special devices are required to retain small catalyst particles.

 The invention is illustrated by the following examples.

Example 1
A mixture of 14 wt. including ternary copolymer of styrene, divinylbenzene and NAC in the form of balls with a particle size of 50 μm, 56 wt. including ground double macroporous copolymer with a particle size of 30-160 microns (specific surface 30 m ² / g), 30 wt. including powdered polyethylene of low pressure (HDPE) and 5 wt. including water formed by extrusion. The obtained cylindrical granules of size d = 5 mm and 1 = 10 mm are sulfonated with sulfuric acid, for which 75 ml of 95% sulfuric acid are poured into 15 g of the molded copolymer and stirred at 96-100 ^° C for 7 hours. The acid is drained, the catalyst is washed with distilled water and dried. PSOE of the catalyst for 0.1 N. NaOH solution equals 3.9 mEq / g.

Example 2
Mixture 56 wt. including ground triple copolymer of styrene, divinylbenzene and methyl methacrylate, with a particle size of 30-160 microns, 14 wt. including milled double macroporous copolymer composition, as in example 1, with a particle size of 30-160 microns, 30 wt. including HDPE in the form of granules d = 3 mm and 5 wt. including water formed by extrusion. The obtained cylindrical granules d = 5 mm and l = 10 mm are sulfonated, as described in example 1. PSOE of the catalyst of 0.1 N. NaOH solution is 4.0 mEq / g.

Example 3
Mixture 35 wt. including ternary copolymer composition, as in example 1, in the form of balls with a particle size of 50 μm, 35 wt. including ground double macroporous copolymer with a particle size of 30-160 μm (specific surface area 25 m ² / g), 30 wt. including HDPE in the form of granules d = 3 mm and 5 wt. including water formed by extrusion. The obtained granules with a diameter of 2 mm and a length of 2-3 mm are sulfonated, as described in example 1. PSOE of the catalyst of 0.1 N. NaOH solution is 4.1 mEq / g.

Example 4
A mixture of 60 wt. including ground double macroporous copolymer with a particle size of 30-160 μm (specific surface area 20 m ² / g), 40 wt. including powdered HDPE and 5 wt. including water formed by extrusion. The obtained granules d = 5 mm and l = 10 mm are sulfonated, as described in example 1. PSOE of the catalyst at 0.1 N. NaOH solution is 3.5 mEq / g.

Example 5
The use of prepared catalysts in the process of dehydration of the TBS azeotrope.

 10 g of catalyst and 50 ml of TBS-water azeotrope are placed in a flask equipped with a reflux condenser with a gas outlet tube and a cooled ampoule to condense the isobutylene emitting. The flask is placed in a boiling water bath. After 2 hours, measure the amount of liquid isobutylene. The activity of the catalyst is calculated as the ratio of the released isobutylene to the theoretically possible, expressed as a percentage.

 The table shows the results of the experiment.

 As can be seen from example 5, the activity of the catalysts obtained by the present method based on a mixture of copolymers of double macroporous and triple gel is higher than the activity of catalysts that can be obtained on the basis of each of the copolymers.

Claims (2)

 1. A method of producing an ionized molded catalyst for organic synthesis by mixing a copolymer based on styrene and divinylbenzene and a thermoplastic material, molding the resulting mixture by extrusion, followed by sulfonation, washing and drying, characterized in that double macroporous is used as a copolymer based on styrene and divinylbenzene styrene-divinylbenzene copolymer mixed with a triple gel copolymer of styrene, divinylbenzene and polar monomer in a weight ratio of 1: 4 to 4: 1.  2. The method according to claim 1, characterized in that the use of these copolymers with a particle size of 30-160 microns.

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