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Treatment method for acyl-chlorination reaction tail gas

A technology of acyl chlorination and reaction, which is applied in the field of tail gas treatment of acyl chlorination reaction, can solve problems such as troublesome operation and treatment, and achieve the effect of safe and convenient production and operation, and create economic benefits

Inactive Publication Date: 2014-07-09
TIANJIN QIDONG CHEM PLANT
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Problems solved by technology

Because sodium sulfite or sodium bisulfite is crystalline solid, large-scale industrial production needs to be filtered and dried, and the operation is troublesome

Method used

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Embodiment Construction

[0027] Below in conjunction with embodiment the present invention is further explained.

[0028] Based on 300kg of hydrogen chloride and 530kg of sulfur dioxide produced by each batch of acid chlorination, after the hydrogen chloride is absorbed and stabilized by the three-stage series hydrogen chloride falling film absorption tower, the content of the first-stage absorption liquid reaches 30-31%, and enters the hydrochloric acid storage tank for standby; the third-stage absorption tower replenishes about 700 kg of water to maintain the stable cycle operation of the system; after the sulfur dioxide gas is absorbed and stabilized by the two-stage series ammonia absorption tower, about 1,500 kg of the first-level ammonia absorption liquid is produced, which is injected into the ammonium sulfite and ammonium bisulfite aqueous solution storage tanks, and Supplement about 1000 kg of 15% dilute ammonia water into the primary ammonia water absorption tower to maintain the system circu...

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Abstract

The invention relates to a treatment method for acyl-chlorination reaction tail gas. The reaction tail gas successively enters a three-step series hydrogen chloride falling-film absorption tower and a two-step series ammonium hydroxide absorption tower; p-chloroaniline and recovered hydrochloric acid are taken as raw materials and subjected to diazotization reaction for generating a diazo salt; and an aqueous solution of ammonium sulfite is taken as a reducing agent, after the diazo salt is dropwise added at room temperature, the recovered hydrochloric acid is dropwise added for acidification hydrolysis and further for preparing p-chlorophenylhydrazine hydrochloride. By employing the method to treat the acyl-chlorination reaction tail gas, tedious technologies for discharging and drying solid materials and selecting low-temperature equipment for liquefying sulfur dioxide are avoided, and the production operation is safe and convenient; and the produced tail gas absorption solution can be used as a raw material for preparing organic chemical products, is environment-friendly and is capable of creating economic benefit.

Description

technical field [0001] The invention relates to a treatment method for tail gas of acid chlorination reaction, by which hydrogen chloride and sulfur dioxide generated in the synthesis process of acid chlorination can be effectively separated to obtain high-concentration relatively pure aqueous solution of hydrochloric acid, ammonium sulfite and ammonium bisulfite, Use this absorption solution as a raw material to synthesize p-chlorophenylhydrazine hydrochloride. Background technique [0002] The acyl chloride reaction is one of the important organic synthesis, and it is widely used. Due to the influence of phosgene transportation restriction in large-scale industrial production, thionyl chloride is often used as the acylating agent, and the reaction generates a mixed tail gas of hydrogen chloride and sulfur dioxide as a by-product. Serious environmental pollution. Recycling with an effective treatment method can obtain a relatively high concentration of hydrochloric acid, a...

Claims

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Application Information

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IPC IPC(8): B01D53/14B01D53/78B01D53/50C07C243/22C07C241/02
Inventor 马荣洁
Owner TIANJIN QIDONG CHEM PLANT
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