SU554263A1 - Method for producing isopropyl benzene - Google Patents

Description

one

The invention relates to a process for the preparation of benzene alkyl derivatives - isopropyl benzene.

Currently, isopropyl benzene (IPB) is obtained by alkylation of benzene with propylene. M. IPB is widely used in the production of phenol, acetone, cc-methylstyrene and as a component of aviation gas. Sulfuric acid, phosphoric acid, supported on diatomaceous earth and other carriers, boron fluoride, alumina, amorphous and crystalline aluminosilicates are used as catalysts for alkanelation.

The alkylation of benzene and its homologues with olefins, alcohols, chlorinated derivatives is carried out at a temperature of 20-350 ° C and a pressure of 0.150 atm. The yield of the alkylation products of benzene with propylene is significantly affected by the temperature and pressure of the process, the molar ratio of benzene to propylene. It is known that in the gas phase the optimum temperature range for the alkylation of benzene with propylene in the presence of aluminosilicate catalysts is 300-350 ° C and elevated pressure.

The most widely used alkylation catalysts are sulfuric acid, aluminum chloride, phosphoric acid on kieselguhr, and other phosphoric acid catalysts.

When using a phosphoric acid catalyst for the alkylation of Beisol with propylene at a temperature of 214 ° C at a pressure of 35 atm and a molar ratio of benzene to propylene of 8: 1, 0.11 mol of IPB per 1 mol of benzene or 0.92 mol of IPB per 1 mol of propylene 1 are obtained.

Various catalysts based on alumina and aluminosilicates are also known.

promoted with boron trifluoride, hydrogen fluoride, boric anhydride.

However, these catalysts, although they have a sufficiently high catalytic activity but the yield of IPB, at a significant consumption of unregenerable catalyst, cause equipment corrosion and contamination of reservoirs with wastewater, as well as a large amount of diisopropyl benzene (DIIPB), triisopropyl benzene (TRIIPB) and tetraisome in the alkylate composition. TIPB), which is due to the low selectivity of the process.

At present, amorphous

and crystalline aluminosilicate catalysts.

The closest in technical essence and the achieved result to the proposed is a method of obtaining nzopropylbenzene,

that is, alkylation of benzene with propylene is carried out in the presence of an aluminosilicate zeolite-containing catalyst at a temperature of 140 ° C, a pressure of 5-10 atm and a molar ratio of benzene to propylene of 3: 1 for 14 hours. %: IPB 20.5, DIPB 10.7, TRIIPB 3.0 (Stage 1). However, when aluminosilicate zeolite catalysts are used, the selectivity of the process is also low (1.6) 2. To increase the selectivity of the process and increase the yield of the target product according to the proposed method, the preparation of isopropyl benzene by alkylation of benzene with propylene in the liquid phase is carried out in the presence of a zirconium silicate zeolite-containing catalyst, weight. %: ZrOa2.0-20.0 ALOZ1.3-6.5 Alkali metal oxides 0.3-0.8 SiOaD 100 In the implementation of the proposed method, the yield of the target product increases to 22% and the selectivity of the process to 15.7. The technology of the method is as follows. Zirconium silicate zeolite-containing catalyst (CSA), which can be synthesized: - by joint precipitation both directly with the zeolite and by subsequent mixing of the zeolite with zirconium silicate; - coagulation of the sols with the introduction of the zeolite into the sol as an aqueous suspension or with a solution of sodium silicate; impregnation of silica gel with soluble zirconium compounds followed by displacement with zeolite. Zeolites can be used as zeolites: NaX, NaV, CaX, CaU, HX, NU, obtained both by preliminary ion exchange for the corresponding cations, and by subsequent ion exchange after the introduction of zeolite X or Y into zirconium silicate. Zirconium silicate zeolite catalysts have a composition, mass,%: Zeolite X or V0.1-50 Zirconium silicate 99.9-50 In this case, the zirconium silicate base may have the following composition, mass. %: ZrOs 0.1-45; SiOg 99.8-54.2; 0.1-0.8. Benzene Limethylbenzene by Propylene Conducted in a four-necked flask equipped with a stirrer, a thermometer, a refrigerator and propylene inlet. The alkylation reaction is carried out in the liquid phase at a temperature of 20-60 ° C and atmospheric pressure. Before carrying out the reaction, the catalysts are calcined at a temperature of 600 ° C for 6 hours in a stream of air free from impurities, then purged with nitrogen until the catalyst is cooled to room temperature. The flask is charged with 50 cm of catalyst and 50 ml of benzene free from impurities. In the examples, the zirconium silicate zeolite-containing catalyst (CCSK) has the following composition, mass. %: ZrOa 5.8; AlaOs 5.4; NajO 0.35; SiOa 88.45. As catalysts for comparison, under similar conditions for testing of CSVC, we used industrial samples of aluminosilicate (ASC) and zeolite-containing aluminosilicate (AShNTs-3) catalysts. Example 1. The benzene alkylation reaction with propylene is carried out at 20 ° C and the propylene feed rate is 0.18 mol per 1 mol of benzene per 1 hour. The reaction is carried out for 3 hours. Alkylate samples are taken every hour and analyzed by chromatography. The results of the experiments are given in table. 1. Table 1 Example 2. Alkylation is carried out at 40 ° C and the propylene feed rate is 0.18 mol / / mol-h. The results of the experiments are given in table. 2. Table 2 5 Example 3. Alkyliroviis .. is carried out ,, np.iL.60 ° С, and the propylene feed rate is 0.18 mol /, 6, mol, h. The data results of the experiments prnademy table. 3., T a b l and c a 3

From tab. 1-3, it is clear that 60 ° C is the optimum temperature for carrying out the alkylation of benzene with propylene on all the catalysts used, therefore, in the following examples, experimental data are obtained from the alkylation of benzene with propylene at this temperature and other propylene nodule rates.

Example 4. The feed rate of propylene 0,087 mol / mol-h The results of the experiments are given in table. four.

Table 4

Example 5. The feed rate of propylene 0.40 mol / mol-h The results of the experiments are given in table. five.

Thus, from Tables 1-5, it follows that the alloys of benzene with propylene allow the preparation of more target α-isopropylbenzene (IPB) and significantly improve the selectivity of the process, since less alkylation secondary products, diisopropylbenzenes (DIIPB), are obtained. Thus, in the case of alkylation of benzene with propylene in the presence of CSC, the maximum yield of IPB is 22.0 wt. % at the temperature of the reTable 5

ten

the stock is 60 ° C and the propylene feed rate is 0.18 mol / mol-h. Under the same conditions, in the presence of an aluminosilicate zeolite-containing catalyst AShNTs-3, the yield is 18.0 wt.%. %, and on the ACK-15.0 wt. % (tab. 3). From tab. 3 tak {e it can be seen that in the presence of CGSC, only 1.4 masses are formed. % DIIPB, and at ASHNZ-3-3,1

masses % and on the ASC - 3.5 mass. %, and the selectivity of the process (ratio of PIB to PFIB) is respectively 15.7; 5.8; 4.3. At other temperatures of the reaction and the feed rate of propylene, the activity and selectivity of the CCSK catalyst are higher than the comparable catalysts.

Example 6. Alkylation of benzene with propylene in the gas-liquid phase under optimal reaction conditions: temperature 60 ° C, molar propylene feed rate 0.18 mol / mol-hour, reaction time 3 hours. The results of the alkylation of banzole with propylene are given in the table. 6

From tab. 6 that within the specified content of the components in the catalyst, the latter has a high catalytic activity for the yield of isoironyl benzene

(IPB) and high selectivity.

Along with this, it is known that alkali metal oxides in alkylation catalysts are home and they are tried to be separated from the structure by ion exchange in the preparation of catalysts. The effect of alkali metals in the form of oxides on the activity of catalysts in the alkylation reaction is shown in Table. 6

Results data on the alkylation of benzene with propylene on various types of zeolite are given in Table. 7

Claims (2)

1. US patent number 3527823, 1970. cl. C 07C 2. The patent of France No. 2012553, 3/00, 1970 (prototype).