Process and system for continuously producing m-aminoacetanilide hydrochloride at high temperature under pressure

Abstract

The invention discloses a process and a system for continuously producing m-aminoacetanilide hydrochloride at high temperature under pressure. The process comprises the following steps: continuously conveying mother liquor water, acetic acid, m-phenylenediamine and hydrogen chloride gas to a closed supergravity reactor, continuously discharging materials in the supergravity reactor, part of the materials passing through a closed first heat exchanger and then returning to the supergravity reactor for circulation, and part of the materials entering a crystallization kettle and then being treatedby a separation device; obtaining an m-aminoacetanilide hydrochloride finished product and mother liquor water, and collecting and recycling the mother liquor water. The system comprises a second heat exchanger, a closed supergravity reactor, a closed first heat exchanger, a crystallization kettle, a separation device and a mother liquor water collection device which are connected in sequence. The second heat exchanger is used for preheating acetic acid and m-phenylenediamine; and a closed loop is formed between the supergravity reactor and the first heat exchanger.

Description

technical field [0001] The invention relates to the technical field of production of dye intermediates, in particular to a process and system for continuous production of m-aminoacetanilide hydrochloride under high temperature and pressure. Background technique [0002] M-aminoacetanilide is a widely used chemical raw material, widely used in disperse dyes, reactive dyes and pharmaceutical intermediates, mainly used to prepare reactive yellow K-RN and disperse dye intermediates, and is in great demand. [0003] The synthesis of m-aminoacetanilide hydrochloride, the traditional production method uses m-phenylenediamine, acetic acid, hydrochloric acid solution and the previous cycle of mother liquor water after concentration, and the temperature is raised to 90°C for reaction. After the reaction is completed, cooling crystallization and suction filtration Or centrifuge to get the product. The separated mother liquor water is distilled under reduced pressure, concentrated and ...

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Problems solved by technology

However, it adopts a batch production process, which requires a large reactor volume, poor mass and heat transfer effects, and large heat loss, which is not conducive to energy saving and emission reduction.

In addition, intermittent production also has problems such as long production cycle and product quality batch differences.

[0005] Patent CN108147975A introduces a process for continuous production of m-aminoacetanilide hydrochloride, which realizes the continuous feeding and discharging of reaction materials. Since the whole production process is under normal pressure conditions, the mother liquor water absorbs hydrogen chloride and increases the concentration. Special absorption towers and other devices, and the increase of the reaction temperature is limited (up to 110°C), which affects the reaction rate, so there are pro

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