New synthesis technology of 2-hydroxybenzonitrile

Abstract

A new synthesis technology of 2-hydroxybenzonitrile comprises the following steps: 1, adding o-chlorotoluene, ammonia gas, oxygen and water vapor to a free turbulent fluidized bed reactor, uniformly stirring above added materials, adding a V-Cr-O and V-P-O fine particle mixture as a catalyst, and heating and reacting the above materials; 2, washing a crude o-chlorobenzonitrile product obtained after the reaction ends with water, and rectifying the crude o-chlorobenzonitrile product to obtain pure o-chlorobenzonitrile; and 3, adding an alkali metal alkoxide solution to the pure o-chlorobenzonitrile obtained in step 2, controlling the reaction temperature, carrying out a reaction under a normal-pressure condition, carrying out reduced pressure distillation after the reaction ends to recover a solvent, and adding hydrochloric acid to the above obtained system in a dropwise manner to carry out acidification in order to obtain solid 2-hydroxybenzonitrile. Compared with the prior art, the technology has the advantages of avoiding of use of phosgene or a phosphorus-containing compound, guaranteeing of the personnel safety of operating personnel, pollution reduction, and facilitation of increase of the productivity of a device and the yield of o-chlorobenzonitrile by using the free turbulent fluidized bed reactor.

Description

technical field [0001] The invention relates to the synthesis of salicylonitrile, in particular to a new synthesis process of salicylonitrile. Background technique [0002] Salicylonitrile, also known as o-hydroxybenzonitrile, is an off-white powdery solid with a very pungent odor. A small amount can affect people's breathing and has a bitter odor. Salicylonitrile is often used as an intermediate in the organic synthesis of Bunirolol and as an intermediate in the fungicide azoxystrobin. There are few reports about the synthesis of salicylonitrile, mainly following two types of reactions: [0003] The first type of reaction is that salicylaldehyde first generates salicylaldoxime with hydroxylamine hydrochloride, and then dehydrates with acetic anhydride or thionyl chloride to obtain salicylonitrile; [0004] The second type of reaction is the dehydration of salicylamide in the presence of phosgene or thionyl chloride or phosphorus oxychloride to obtain salicylonitrile; [...

AI Technical Summary

Problems solved by technology

However, this method is cumbersome to operate, the cost of raw materials is relatively expensive, the total yield of salicylonitrile is low, and a large amount of industrial wastes are generated, which is not conducive to industrial production

The second type of method is the nitrilation reaction of amide compounds. This type of reaction has simple steps and less waste, but the highly toxic gas phosgene is used in the process of use, which is likely to cause environmental pollution and threaten the personal safety of operators.