SU891146A1 - Catalyst for vapour-phase isomerization of cyclohexanoxime to e-caprolactam - Google Patents

Description

(54) CATALYST FOR PARAPHASE IZOMERIZATION OF CYCLOGEXANOXYM IN - CAPROLACT

one

This invention relates to the production of cyclohexanone oxime isomerization catalysts in -caprol ctam in the vapor phase.

A known catalyst for vapor-phase isomerization of cyclohexanone oxime in -caprolactam, which is a decationized zeolite of the type Y 1.

When testing this catalyst in the process of isomerization of cyclohexanone oxime at 380 ° C, a space velocity of 0.7 and a working time of 60 minutes. the degree of conversion of the raw material reaches 85% with a selectivity of 76%, while after 20 hours of operation of the catalyst the degree of conversion decreased to 30% while reducing the selectivity to 50.0%.

The closest to the proposed technical essence and the achieved effect is catalyst 2 for vapor phase isomerization of cyclohexanone oxime in E - caprolactam, containing decationized type Z zeolite and boron compound, which contains aluminobras of composition, - 45% B2. with the following content of components, weight,%:

Composition alumoborate

9.1 - 37.5

45%

lOj

BUT

Decationized type U zeolite Else 5 The well-known catcher has a high activity (degree of conversion of raw materials 95-100%), but not high enough selectivity (84%) and stability (after 20 hours of operation, the selectivity of the catalyst is 80% at 75% conversion) . The purpose of the invention is to increase the stability and selectivity of the catalyst.

15 To achieve the goal, a catalyst for vapor phase isomerization of cyclohexanone oxime B - caprolactam containing decationized type Y zeolite and boron compound, 20 which contains boro lumosilicate, is used in the following ratio of components, wt. %:

Boraluminosilicate 70 - 90 Decathioned 25 U-type zeolite Else

A distinctive feature of the invention is the content of boro-aluminum silicate as a boron compound and the ratio of components. The proposed catalyst in comparison with the known possesses universal selectivity and stability.

Thus, the degree of conversion of the raw material in the presence of a HacTOHaiero catalyst is 99-100%, the selectivity of the catalyst is 90.6 - 91.0%, and after 20 hours of operation the selectivity of catalysis, the torus is 84% at 100% conversion.

The catalyst is obtained by joint precipitation of aluminum and silicon hydroxides from aqueous solutions of their salt by action of ammonia, followed by modification of boric acid, and adding 30% concentration of decationized type U zeolite to the aqueous suspension and calcining the precipitate at 500 ° C.

The invention is illustrated by examples.

Preparation of boraluminosilicate.

Example 1. To obtain an aluminosilicate composition of 80% (30%. 70% Si6) J f 20% B, to 4% HOM-j aqueous solution of sodium silicate (265.05 g of Na, in 6476 ml) acidified with dilute sulfuric acid. acid (1: 1) to pH 1, add 4% aqueous solution of aluminum sulphate (156.792 A 1 | 2 (50) -.. 18H ,, 0 in 3844 MJI water) and precipitate a mixture of hydroxides with concentrated ammonia at pH 8-8.5 with vigorous stirring. After sedimentation, the gel is left to mature for 1-2 hours;

those are washed from SO ions

and activate with 0.2 n n solution of ammonium chloride. Then the aluminosilicate gel is washed with distilled water to a negative reaction to the chlorine ion in the filtrate, sucked off from the excess water in a Buchner funnel and subjected to hydrothermal aging in an autoclave for 5-6 hours at 120 140 s. At the end of the hydrothermal treatment, the gel is again sucked off on a Buchner funnel and boric acid in the amount of 31.72 mg of dry boric acid per gram of gel is added to the wet gel, the mixture is thoroughly mixed and slightly dried in air

When producing aluminosilicate with 10% or 25%, the amount of boric acid applied per 1 g of gel is reduced or increased, respectively.

Example 2. To obtain an aluminosilicate composition of 80% (50% SiOn) + 20% to 4% aqueous solution of sodium silicate (189.33 g, and 510 g in 6409 ml of water), acidified with diluted 1: 1 sulfuric acid to pH 1, add 4% aqueous solution of aluminum sulphate (261.44 g A) f (SO) j 18 NPO in 4625 ml of water) and precipitate a mixture of hydroxides with concentrated ammonia solution at pH 8-8.5 at

intensive mixing. Then all operations are repeated as in example 1.

Preparation of decationized type y (OU) zeolite.

Example 3. Air-dry powdered zeolite NaJ with a ratio of 6 and containing about 23% of water is subjected to ion exchange in a solution of 1 n ammonium chloride at the rate of 6 ml of solution per 1 g of zeo; shta. The treatment was carried out three times with intermediate flow in a stream of water vapor for about an hour. Residual sodium should not exceed 0.20, 3 mg eq / g.

X-ray structural analysis of the obtained decayed zeolite shows a clear diffraction pattern testifying to the preservation of its crystal structure in the process of thermoprize activation. Differential-thermal analysis indicates a high thermal stability, corresponding to the thermal stability of yj bTpacTa6Hj boro zeolite.

Pri1 otlovlenie catalyst.

Example 4. A catalyst having a chemical composition of E0% 80% (30% .70% SiO,) + 20% + 10% NU is prepared as follows.

To 1/4 of the alumina-silica gel (280 g) obtained in Example 1, with vigorous stirring, a 30% concentration of 2.222 g of decationized type U zeolite is added in an aqueous suspension and stirred for an hour. The resulting mass is dried in air for 20 hours and formed into granules of 2 x Zg-4m in size which are dried for 48 hours at room temperature, 6 hours at 120 ° C in a drying cabinet and calcined for 4 hours at 500 seconds with a very slow rise in temperature during drying and calcination in order to avoid loss of boron oxide and destruction of the zeolite structure.

The content of boron oxide was determined by the method of extraction with hot water with a vat: it was precipitated as barium borotartrate.

Example 5. A cat.apizator (having a chemical composition of 80% 80% (30% 70% SiO, 2) + 20% + 20% NU, is prepared as follows.

To 1/4 of the alumina-silica gel obtained in Example 1, with vigorous stirring, in the form of an aqueous suspension, 30% concentration, 5,000 g of decationized type U zeolite, are stirred for an hour. Then, all operations are repeated as in example 4.

Example 6. A catalyst having a chemical composition of 70% 30% (30% - 70% Si05) + 20% Bn, 0g + 30% NU, is prepared as follows. To 1/4 of the alumina-silica gel obtained in Example 1, with vigorous stirring, a 30% concentration of 8.571 g of decationized type U zeolite is added in an aqueous suspension, stirred for an hour. Then, all the operations are repeated as in Example 4. Example 7. A catcher with a chemical composition of 80% 30% (50% Al, 0, .j, 50% SiO) + 20% 20% OH, is prepared in the following way. To 1/4 part of alumina-silica gel ("295 g), obtained according to example 2, is added with intensive alternation in the form of an aqueous suspension and 30% concentration of 5; 00 g of decationized zeolite NU. The mixture is stirred for one hour and then all operations are repeated as in Example 4. P. Example 9. A catalyst having a chemical composition of 80% 90% (50%. 50% SiOQ) + 10%, + 20% of OH is prepared according to Example 4 with the only difference that 5.00 g of decationized zeolite is introduced into the silica-alumina obtained according to Example 2, but the amount of boric acid taken to modify the gel was 15.86 mg per 1 g gel Then all operations are repeated as in example 4.

Comparative data on the testing of the activity of this catalyst and known catalysts (temperature S25 s, volumetric rate (OS) 1 test duration 60 min.).

Table 1 Example 9. A catalyst having a chemical composition of 80% 75% (30%. 70% SiO) + 25% B. 420% NU is prepared as in Example 4 with the only difference that 5.00 g of decationized The zeolite was introduced into the alumina-silica gel obtained in Example 1, but for modifying the gel, the amount of boric acid was 42.29 mg per 1 g of gel. Then all operators are repeated as in Example 4. The catalyst is tested in vapor phase isomerising, cyclohexanone oxime in t - caprolactam at 250-325 ° C, atmospheric pressure and a space velocity of 1.0 h. Cyclohexanone oxime is supplied to the reaction zone in the form of a 17% solution in toluene, in a stream of nitrogen (5 liters of nitrogen per 10 meters) 1 catalyst per hour. Before starting the experiment, the catalyst is activated by air for 2 hours at the temperature of the experiment. and then purged with nitrogen for 30 minutes. The reaction products are analyzed by gas chromatography using a column filled with 15% PEG-4000 on zeolite - 545, 60-80 mesh, treated with alkali. Helium carrier gas, column temperature 150 ° C, detector-katharometer. The test results of the activity of the proposed and known catalysts are given in table. 1 and 2.

13 80/3% NU + 16.7% (Alj Oj-45% 62.03) after .20 h of operation, OS 0.7 h- ,.

. 70% 80% (30% 70% S i 0 (j) + 20% BPO,

14 OS 0.4 CHOS 3.0 270 ° C

Known catalyst The effect of temperature on the activity of catalysts (bulk velocity 1

Continued table. one

-G-G75, 0

80.0

WELL

99.0

75.7 89.2 74.0 Table 2 of the present and well-known h, continuation. experience 60 min.)

80% 80% (30% AljOj 70% SiO,) + + 20% BriOj + 20% NU

90% 80% (30% 70% SJO ,,) + + 20% + 10% WELL

70% G80% (30% AliOj- 70% S i 0l) + + 20% + 30% NU

83.3% OU + 16.7% (A1 „0. -45%)

, 7 h)

Claims (2)

Decationized type Y zeolite Known catalyst (Claims of the invention) A catalyst for vapor phase isomerization of cyclohexanone oxime into caprolactam containing a decationized type Y zeolite and a bora compound, characterized in that, in order to increase the stability and selectivity of the catalyst, it contains 100 80.5 100 82.0 100 84.0 100 91.0 280 82 ,: 96, 0 79.5 74.0 300 60.1 91.0 300 76.0 85.0380 un). boraluminosilicate in the following ratio of components, weight. %: Boralumosilicate 70-90 Dication-free zolite of the Oostal type. Sources of information taken into account in the examination 1. Jandls P.S., P..B.Venito. Organs Reactions Catalyzed by Cristalline A I urn I no si 1 iаtes Beckmann Rear89114610 agaHu1 | z r ° ;; r% 5L% k USSR author's certificate J. Catalys.s, 6, No. 2, 1966, p. 245-. 2676377, class B 01 J 29/04, 1978  W-r f-l G-1 rt, J- yy. 2. Author 2676377,: (prototype).