Synthetic method of high-yield o-hydoxybenzonitrile

Abstract

The invention provides a synthetic method for high-yield o-hydoxybenzonitrile. The synthetic method mainly comprises the following steps: 1) adding salicylamide and a solvent xylene in a reaction vessel, starting the reaction vessel for full stirring; 2) turning on a jacket for steam heating, simultaneously introducing phosgene for a reaction; 3) after the reaction is complete, introducing nitrogen for expelling gas, setting an absorber at a gas outlet of the reaction vessel; 4) transferring a mixture in the step 3) to a rectifying tower, respectively collecting the fraction with the temperature of 137-140 DEG C and 145-155 DEG C; 5) cooling the fraction with the temperature of 137-140 DEG C and distilling the fraction to obtain the solvent xylene; and 6) condensing the fraction with the temperature of 145-155 DEG C in the step 4) and slicing the fraction to obtain the product o-hydoxybenzonitrile. The method is mature and reliable, the product quality is high, the raw material consumption is low, the cost is low, compared with the same kind of the product, the content of the o-hydoxybenzonitrile is increased by 1.5%, and the impurity is decreased by 1.0%.

Description

technical field [0001] The invention relates to the synthesis of salicylonitrile, in particular to a high-yield synthesis method 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, less three wastes, complex post-treatment, and no phosgene treatment device. The by-products benzoxazole and salicylonitrile are easily produced in the reaction process. The total yield is about 80%