Treatment method for tail gas produced by reaction of sulfonyl chlorination

Abstract

A treatment method for tail gas produced by reaction of sulfonyl chlorination comprises the following steps: (1), the tail gas produced by the reaction of sulfonyl chlorination is injected into a tertiary series hydrogen chloride falling-film absorption tower, and absorption liquid in a primary hydrogen chloride falling-film absorption tower becomes hydrochloric acid to enter a hydrochloric acid storage tank; (2), tail gas after the hydrogen chloride gas is absorbed by the tertiary hydrogen chloride falling-film absorption tower and then passes through a secondary series aqua ammonia absorption tower, sulfur dioxide gas in the tail gas is absorbed by aqua ammonia in a primary aqua ammonia absorption tower, and the residual tail gas enters a secondary aqua ammonia absorption tower; (3), ammonium sulfite water solution is prepared; (4), parachloroaniline and recovered hydrochloric acid in the primary hydrogen chloride falling-film absorption tower are taken as raw material, and sodium nitrite water solution is added into the raw materials to produce parachlorobenzene diazonium chloride; (5), parachlorobenzene diazonium chloride is dripped into the ammonium sulfite water solution to produce diazonium parachlorobenzene disulfonate; and (6), recovered hydrochloric acid is dripped into the diazonium parachlorobenzene disulfonate to prepare parachlorobenzene hydrazine dihydrochloride. The treatment method effectively separates the tail gas, utilizes hydrochloric acid and ammonium sulfite, which are recovered by the tail gas, to prepare the parachlorobenzene hydrazine dihydrochloride, thereby being environment-friendly and economical.

Description

technical field [0001] The invention relates to a treatment method for acid chlorination reaction tail gas. Background technique [0002] Acyl chloride reaction is one of the important organic synthesis methods with a wide range of applications. Due to the impact of limited transportation of phosgene in large-scale industrial production, thionyl chloride is often used as an acylating agent in the acyl chloride reaction. This reaction generates a tail gas containing a mixed gas of hydrogen chloride and sulfur dioxide, which seriously pollutes the environment. [0003] Existing processing methods of acid chloride reaction tail gas are simply summarized as follows: [0004] 1. Alkaline direct absorption method. Use a certain concentration of lye to directly absorb hydrogen chloride and sulfur dioxide gas in the tail gas to form sodium chloride and sodium sulfite. This method produces a large amount of brine, and secondary biochemical treatment is required to meet the emission...

AI Technical Summary

Problems solved by technology

[0009] The main purpose of the present invention is to overcome the above-mentioned shortcomings existing in the existing tail gas treatment method, and provide a treatment method for the tail gas of the acid chlorination reaction, which can effectively separate the mixed gas of hydrogen chloride and sulfur dioxide contained in the tail gas produced by the acid chlorination reaction , the available pure high-concentration hydrochloric acid and ammonium sulfite aqueous solution, the separated products can be used as raw materials for the synthesis of p-chlorophenylhydrazine hydrochloride, which not only solves the problem of environmental pollution, but also creates economic benefits