SU622802A1 - Method of obtaining higher alkylchlorbenzols - Google Patents

Description

The invention is related to the preparation of higher (C5 C-alkyl) chlorobenzenes. These compounds are used in the synthesis of a variety of practically valuable products — plasticizers, stabilizers, emulsifiers, etc. A method is known for producing higher alkylchlorobeneols by chlorinating aromatic hydrocarbons in the presence of nitrate ions, hydrochloric acid, and other strong acids in an aqueous medium 6 oxygen atmosphere at 60-150C l. Carrying out the process under such conditions results in a complex CM of products, which are lichlorinated as c. draw and in the side chain. This property, as well as the strong corrosion of the apparatus, make this method unacceptable for efficient production of alkyl chlorobenzenes. The closest to the invention to the technical essence and the achieved result is a method of obtaining higher (Cj-Cq-alkyl) chlorobenzenes by chlorination of the corresponding aromatic hydrocarbons with molecular chlorine in an organic solvent at elevated temperature in the presence of a metallic iron catalyst 2. According to this method Chlorinated C – C hydrocarbons are used as a solvent and the process is carried out at a temperature of 70–160 ° C. The ratio between hydrocarbon and chlorine is 1: 2. However, the yield of the target product does not exceed 50 mol.%, And conducting a reaction at a relative 1 {; very high temperature requires substantial energy costs. The aim of the invention is to increase the yield of the target product and decrease the reaction temperature - this is achieved by chlorinating aromatic hydrocarbons with molecular chlorine in the presence of a metallic iron catalyst in an organic solvent, acetic acid, at a temperature of 44-56 ° C and a ratio between the initial hydrocarbon and chlorine 1: 1,2. Distinctive features of the invention are the use of acetic acid as an organic solvent and carrying out the process at a temperature of 4-4-56 ° C and a ratio between the initial carbon and chlorine equal to 1: 1.2.

When carrying out the reaction using the proposed method, the target products are obtained with a yield of up to 74, mrl%, the reaction temperature is reduced to 44-56 0.

As a result of the reaction, a mixture of ortho- and para-substituted monochlorine derivatives is obtained, in which the content of the ortho-isomer is 35-40%. The resulting product without additional separation can be used for further processing.

The reaction is carried out in a three-necked glass flask equipped with a reflux condenser, a mechanical stirrer and a chlorine supply unit.

N-alkyl substituted benzene, toluene, and m-xylene are obtained as the starting hydrocarbon, obtained by alkylation of the latter with the appropriate C3C-olefins of normal structure, isolated from the industrial product of the thermal decomposition of n-paraFins.

The reaction is exothermic, the reaction temperature is maintained by adjusting the chlorine feed rate.

At the end of the reaction, the liquid phase is separated by decantation from the catalyst and first subjected to atmospheric distillation, with a solvent, and then vacuum distillation, with the separation of unreacted hydrocarbon fractions and the alkyl chlorobenzenes desired product. .

A significant discontinuity in the TeMnepaTv boiling {of SIMILAR hydrocarbons and their chlorine derivatives ensures the completeness and purity of the selection of the corresponding components. Unreacted hydrocarbon can be reused to produce the desired product.

The obtained alkylchlorobenzenes waspuuaMT, identified by mass and IR spectroscopic methods. The data obtained confirm the formation of alkylchloride salts, and the percentage ratio between the ortho and para isomers for heptyl and octylchlorobenzenes is 35-40: 65-60. with

5 Example. 176 g of n-heptylbenzene, 5 g of metallic iron (chips) and 50 g of acetic acid are loaded into the reactor. 85.2 g of gaseous chlorine are passed through the mixture for 8 hours at, the molar ratio.

the suspension between the aromatic carbohydrate. RODOG4 and chlorine 1: 1,2. Conversion of n heptylbenzene to heptylchlorobeneol (62 mol.%, The yield of heptylchlorobenzene to the recovered hydrocarbon is 73 mol.%. The selectivity of heptylmonochlorobenzene is 99.5%.

The data of a number of examples carried out in a similar way are tabulated. When conducting the reaction, use-. 85.2 g of chlorine gas and 5 g

metallic iron (shavings). The molar ratio between alkylbenzene and chlorine is 1: 1.2.

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Claims (2)

IUt4. . , 7 62280 Claims The method of producing higher alkyl chlorobvsols containing alkyl with 5-9 carbon atoms by chlorinating the corresponding aromatic hydrocarbons with chlorine in the front of an organic solvent at a fermented temperature in the presence of a catalyst - metallic iron, characterized in that increasing the yield of the target 28 product and lowering the reaction temperature, the process is carried out using acetic acid as an organic solvent at a temperature of 4456 C and a ratio between at the initial hydrocarbon and chlorine equal to 1: 1,2; Sources of information taken into account during the examination; 1. US patent No. 3717684, kl.260-650, 1973. i. „,„ P, l “ 2. Japanese patent 49-48298, cl. 16С21, 1974.