SU68792A1 - Apparatus for continuous chlorination of benzene - Google Patents

Description

Methods for the continuous chlorination of benzene are known. To complete this process, a device is proposed, which is schematically shown in the drawing.

Chlorination of benzene is carried out in a cast-iron vertical column / filled with cooled liquid. Benzene from mernik 2 and chlorine are fed to the bottom of the column, the quantities of which are measured with rotameters 5.

The product, as it is formed, is automatically withdrawn from the top of the column to neutralization. The optimum temperature of the chlorination process is 30 ° C, the optimum degree of chlorination (percentage of chlorine in the cooled mixture) is 50 ° / o.

A mixing condenser 6, filled with iron rings serving as a catalyst for chlorination, is installed above the column (no iron rings are introduced into the column / catalyst in the form of iron rings).

A small part of the circulating cooled liquid after water cooling is subjected to brine cooling in a refrigerator 7 to -5 ° C and then supplied to irrigation in displacement condenser 6. Here benzene vapor is collected from hydrogen chloride gas. At the same time, the cooled liquid, passing through the displacement condenser, dissolves the catalyst (ferric chloride) and feeds the last column. Due to this, the concentration of catalyst in the column is significantly lower than the saturation concentration, which favorably influences the yield of chlorobenzene.

The main advantages of the proposed device are the following:

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a) The ability to conduct the process in a continuous way; the device is distinguished by the simplicity of the shredding process and the ease of adjusting the mode.

b) Greater productivity: the specific volumetric column capacity (the amount of chlorobenzene obtained per hour from 1 m of the reaction volume of the column) is on average 250 kg / tea (16-17 kg / hrm with a periodic method); the specific surface productivity of the column (the amount of chlorobenzene obtained per hour from 1 lgz of the cooling surface of the column) is 12–13 kg / tea (6–7 kg / tea with a periodic method).

c) High yield of chlorobenzene; at an optimum temperature of 30 ° C and the degree of chlorination of bo / o, the ratio of chlorobenzene and polychloride is from. 12: 1 to 14: 1, i.e., almost two times more than with the periodic method.

Neutralization of the cooled liquid is carried out in an injector with a 2-Zo / o-soda solution, to which salt is added to obtain a specific weight of solution 1.1.

After neutralizing and drying it with calcium chloride, the rectification of the chlorinated mixture is carried out in two successive distillation units in a known manner.

Subject invention

A device for the continuous chlorination of benzene and the like, consisting of a column with devices for the continuous introduction of chlorine and benzene into its lower part and removal of the chlorination products from the upper part, characterized in that the column is connected in the upper part to a mixing condenser filled with iron and an irrigated part of the circulating cooled liquid, in order to trap benzene vapor or similar from the vapor-gas mixture leaving the column, and also to introduce an iron catalyst into the column in the form of dissolved packing. condenser mix.

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