Preparation method of salicylamide

Abstract

The invention provides a preparation method of salicylamide and belongs to the field of fine chemicals. The preparation method is characterized by comprising the following steps that under normal pressure, methyl salicylate and a buffer solution are added into a reaction bottle according to the weight ratio being 1:2-4, the temperature is increased to 30-60 DEG C, ammonia gas is introduced continuously to conduct an amidation reaction, the reaction temperature is controlled to be 40-60 DEG C, the ammonia gas is stopped being introduced after the reaction is conducted for 1 hour, the temperature is decreased to 20-25 DEG C through cooling, centrifugation and drying are conducted, and the salicylamide is obtained. By the adoption of the preparation method, the hydrolysis side reaction of methyl salicylate is effectively reduced, the prepared salicylamide is high in yield, easy to separate, high in purity and free of mixed color in appearance, and the preparation method is low in cost and environmentally friendly.

Description

technical field [0001] The invention relates to a preparation method of salicylamide, which belongs to the field of fine chemicals. Background technique [0002] Salicylamide is an important fine chemical, which is widely used in the large-scale industrial production of fine chemicals such as 5-acetyl salicylamide, benzalidine, leather antifungal agent No. 1, and salicylonitrile; , which itself is an important antipyretic and analgesic, used to treat fever, headache, neuralgia, arthralgia and active rheumatism. [0003] At present, the laboratory has extensively developed the one-step preparation process of phenol and urea (for example: CN1923800A), but this small-scale test process has fatal defects such as high reaction temperature and low yield, which cannot be applied to scale-up production. [0004] The existing mainstream production process of salicylamide generally uses methyl salicylate and ammonia as the basic raw materials and methanol as the reaction medium (for ...

AI Technical Summary

Problems solved by technology

[0005] 1) The amount of organic solvent is large, and its recovery rate is low, which is easy to cause environmental pollution;

[0006] 2) The side reaction of hydrolysis leads to unsatisfactory yield, which is generally lower than 80%, and the production cost is high;

[0007] 3) The reaction conditions are harsh, the post-treatment process is complicated, the purification operation is cumbersome, and the equipment requirements are high;