Crystallization treatment process of paracetamol acylation material liquid

Abstract

The invention relates to a crystallization treatment process of paracetamol acylation material liquid, which is characterized in that the process comprises the following steps of: a preheating step for preheating a crystallization container; and a crystallization treatment step for introducing the acylation material liquid into the crystallization container and performing crystallization treatment of the acylation material liquid. Through preheating the crystallization container to a specified temperature, the impact to the bottom of the crystallization container caused by the material liquid of the high-temperature acylation material is effectively avoided; the generation of phenomena of porcelain crack and caking is solved; the service life of the equipment is prolonged; the crystal form of the crystallized material is protected favorably; the generation of powder material is reduced; and the product quality is improved.

Description

technical field [0001] The invention relates to a crystallization treatment process, in particular to a crystallization treatment process of an acylation feed solution in the production process of acetaminophen (that is, a crystallization treatment process of acetaminophen acylation feed solution). Background technique [0002] After the p-aminophenol and glacial acetic acid are batched in the batching container, they are put into the acylation kettle and acylated at 140°C. During the acylation process, water will evaporate, and a part of acetic acid will be brought out when the water evaporates (that is, the following steam acid), the acylated material needs to be crystallized after the acid distillation is completed. [0003] At present, in the production process of acetaminophen, after the acylation and distilling of p-aminophenol and glacial acetic acid, although it is possible to directly carry out cooling and crystallization in the acylation tank, and then centrifuge, ...

AI Technical Summary

Problems solved by technology

[0003] At present, in the production process of acetaminophen, after the acylation and distilling of p-aminophenol and glacial acetic acid, although it is possible to directly carry out cooling and crystallization in the acylation tank, and then centrifuge, but if that takes up the acyl The time for the tank will increase, which will affect the acylation reaction of the next batch of materials. In order to speed up the material circulation process and increase the output, two tanks are selected for acylation and crystallization respectively.

That is, in order not to occupy the resources of the acylation tank, after the acylation reaction and the acid steaming process are completed, the feed liquid (hereinafter referred to as the acylation feed liquid) obtained after the completion of the acylation acid steaming process is put into another enamel reaction tank (also called crystallization tank) to carry out the crystallization reaction, during this reaction process, since the temperature of the acylation feed liquid reaches 130°C, and the temperature of the crystallization tank is relatively low, if the high-temperature acylation feed liquid meets the wall of the crystallization tank with a large temperature difference or At the bottom, there will be a phenomenon that the acylation feed liquid will agglomerate on the wall or bottom of the crystallization tank due to chilling, resulting in that the overall crystal form of the product does not meet the requirements, and the wall or bottom of the crystallization tank will also be damaged due to severe thermal shock. It is easy to appear the phenomenon of broken porcelain, thereby reducing the service life of the equipment. In the place where broken porcelain occurs, the acid contained in the acylation liquid will soak into the broken porcelain point and corrode the crystallization tank (iron enamel tank). Timely discovery and repair of the broken porcelain, the tank body at the broken porcelain will be corroded and cause the acylation material liquid placed in it to seep out or the circulating medium in the jacket enters the acylation material liquid of the crystallization tank, affecting The quality of the crystallization material, if it is more serious, the crystallization tank will be scrapped