SU957946A1 - Method of preparing zeolyte containing catalyst for isomerization of naphtene hydrocarbons - Google Patents

Description

BACKGROUND OF THE INVENTION The invention relates to preparative & zealot zeolite-containing catalysts for the isomerization of naphthenic hydrocarbons.

 A known method of preparing a catalyst for the isomerization of hydrocarbons by high-temperature treatment of zeolite NN4, comprising treating the zeolite at 315-760 ° C in a stream of dry hydrogen for 1-6 hours, treating the zeolite in air stream at 315-769 ° C for 0.25-2 hours and then processing the zeolite in a stream of dry hydrogen 0.25 h 1.

The disadvantage of this method is that it does not produce a catalyst with high activity in the isomerization of saturated hydrocarbons. This is due to the fact that with single-stage calcination of a zeolite at a temperature below 800-840 ° C in the absence of water vapor, for example, in a stream of dry hydrogen, a significant part of the zeolite crystal structure is destroyed.

The closest to the proposed technical essence and the achieved result is the method of preparation of zeo-litcontaining

catalyst for naphthenic hydrocarbon isomerization, including treating NaY zeolite with ammonium salt solution, calcining the obtained NH4NaY zeolite at 520-540 ° С, secondary treatment of HNaY zeolite with an ammonium salt solution, followed by calcining the obtained HNH4Y zeolite at 800-840 ° С in the presence of vapor

10 water and treatment of the obtained zeolite HY with a solution of a salt of a noble metal, for example, Pt (NN4) 4 С l, j. The content of the noble metal in the catalyst is 0.5 wt.% C22.

15

The disadvantage of this method is to obtain a catalyst with insufficient activity, namely: the catalyst requires high process temperatures and pressures (25020– 320 ° C, 2-3 MPa)

The purpose of the invention is the preparation of a catalyst with increased activity.

This goal is achieved by

25 that, according to the method for producing a naphthenic hydrocarbon isomerization catalyst, by treating an NaV zeolite with a solution of ammonium salt followed by calcining the resulting 30 zeolite at 520–540 ° C, re-treating it with a solution of ammonium salt, and calcining the resulting NMH4U zeolite at 800–840 ° C In the absence of water vapor, the zeolites NH4NaY and HNH4Y after calcination are additionally treated with hydrogen at 200-300s for 2-3 hours. The essence of the process is as follows. ZeYlite NaY is treated with 0.1-1 N, ammonium salt solution, as which any soluble ammonium salt, for example NH4C, is chosen at 20-100 ° C. The process is carried out for 3-8 hours, the resulting zeolite is calcined at 520-540 ° C for 2-3 hours and then treated with hydrogen at 200-300 ° C for 2-3 hours. The resulting material is subjected to secondary processing 0.1-1 n ammonium salt solution at 20–100 ° C for 48 h, calcined HNH4Y zeolite obtained at 800–840 ° C in the presence of water vapor for 2–3 h and treated with hydrogen at 2OO – 300 ° C for 2–3 h. Example 1. DL of zeolite NaY with a molar ratio S iOr: A j equal to 4.2 is placed in a thermostatted flask, 500 ml 0.2 n are added there too. NN401 solution, the resulting mixture was stirred at 100 ° C for 4 hours. After that, the zeolite was washed with distilled water until there were no C1 ions in the drain and was pierced at 540 ° C for 2 hours. Next, the resulting sample of zeolite was placed in a tubular reactor and treated with hydrogen at 200 ° C for 2 h (consumption of hydrogen 1.5 l / h). Later, the operations of treating HNaY olite with NN401 solution are repeated and washed with water under the same conditions. The zeolite HNH4Y is then calcined for 2 hours at 800 ° C in the presence of water vapor and again treated with hydrogen at 200 ° C for 2 hours. The result is a zeolite HY with a residual content NarjO 0.25 wt.%. Example 2. All operations listed in example 1 are performed, but the hydrogen treatment steps are carried out for 3 hours. Example 3. All operations listed in example 1 are performed, but the hydrogen treatment steps are carried out at 300 ° C for 1 hour. Example 4. All the operations listed in example 1 are carried out but hydrogen treatment is not carried out. Example 5 (for comparison). All operations listed in example 1 are performed, but the stage of treatment with hydrogen is not carried out. The resulting HY zeolite is impregnated with 100 ml of a 0.01 M solution of P t (NN4) 43 C Ij and NN40 in a volume ratio of 1 at room temperature for 10 hours, then dried for 4 hours, calcined in air flow at 500 ° C for 3 hours, and reduced with hydrogen at 350 ° C for 5 hours. The platinum content in the resulting catalyst is 0.5% by weight. Example 6 (for equation). 30 g of NaY zeolite with a molar ratio of SiOij: AI., Equal to 4.2, are treated with 1N. NH4C1 solution at 100 ° C for 50 hours. The result is an NH4Y zeolite with a residual content of 0.4 wt.%. Next, the obtained sample of zeolite is calcined in a stream of dry hydrogen at 540 ° C for b h, then treated with dry air at 500 ° C for 1 h and again treated with hydrogen at 500 ° C for 2 h. Catalyst specimens prepared in examples 1 -6 is used to isomerize cyclohexane and methylcyclopentane. The test results of samples of catalysts prepared in examples 1-6 are given in the table.

Isomerization of cyclohexane in a flow installation

Product yield, wt.%: Methylcyclopentane cracking products

Isomerization of methylcyclopentane on a pulsed installation

28.5

29.5

25.3

29.0 4.2 2.0 6.5 6.7 Experimental conditions Experimental conditions;

As can be seen from the presented data, the samples of catalysts prepared by the proposed method have a higher activity: the yield of methylcyclopentane is 4-8 may.% Higher than in the case of catalysts prepared by lime methods (examples 5-6).

Claims (2)

1. US patent 3390101, cl. 252-455, published. 1968. 2. Kozlov N.S., Urbanovich I.I. et al. Isomerisation of i-hexane on catalysts containing platinum on a decationized zeolite 5 Y, stabilized at different temperatures. - Lime Academy of Sciences of the BSSR. Ser. Chemical Sciences, 1975, № 3, p. 10-13 (prototype). 230 ° C, a volumetric feed rate of 1.5 h, the sample from example 5 is tested in a stream of hydrogen, the molar ratio hydrogen: cyclohexane is 2: 1, the pressure is 0.1 MPa. 280 ° С, image1№1 according to examples 1-4 and b I test in a stream of nitrogen, the sample according to example 5 in a stream of hydrogen, the flow rate of carrier gas is 100 ml / min.