Preparation method of o-methylbenzoyl nitrile

Abstract

The invention discloses a preparation method of o-methylbenzoyl nitrile, the preparation method comprises the following steps: dissolving o-toluic acid in a toluene solvent, dropwise adding thionyl chloride for reaction, and removing a small amount of unreacted thionyl chloride at low temperature after the reaction is finished to obtain a solvent-containing intermediate o-methylbenzoyl chloride solution; then directly adding a catalyst, solid sodium cyanide and a reaction aid, continuing a second-step reaction, after the reaction is finished, adding a saturated sodium chloride solution into a reaction solution, pulping and splitting phases, and washing an organic phase once by using the saturated sodium chloride solution; and carrying out reduced pressure distillation on the organic phase to recover the solvent, and carrying out vacuum rectification to obtain the o-methylbenzoyl nitrile product with the purity of more than 99.0%. According to the method, the o-methylbenzoyl nitrile is synthesized by taking o-toluic acid as an initial raw material through a one-pot method, the method is simple and feasible, a safe and environment-friendly treatment process is provided for waste gas and a byproduct sodium chloride salt generated in the reaction process, and the whole technological process is green and environment-friendly and is suitable for large-scale industrial enlarged production.

Description

technical field [0001] The invention relates to the technical field of medicinal chemistry, and more specifically relates to a preparation method of o-toluonitrile. Background technique [0002] Trifloxystrobin ((2Z)-2-methoxyimino-2-[2-[[1-[3-(trifluoromethyl)phenyl]ethylideneamino]oxymethyl]phenyl]acetic acid Methyl ester) is a low-toxicity, high-efficiency, broad-spectrum, systemic fungicide. It is one of the mainstream products in agricultural fungicides, and it is harmless to mammals. It can be rapidly degraded in soil or water, and it is harmful to the environment. friendly. At present, the main difficulty in the synthesis of trifloxystrobin is the synthesis of 2-halomethyl-α-methoxyiminophenylacetic acid methyl ester. 2-halomethyl-alpha-methoxyiminophenylacetic acid methyl ester can be o-toluic acid as raw material, and reflux with thionyl chloride as a chlorination reagent to obtain o-toluyl chloride; then with sodium cyanide Or react with potassium cyanide to obt...

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Problems solved by technology

[0003] However, there are certain defects in the synthetic methods of o-toluonitrile disclosed in the prior art, which cannot meet the requirements of practical application.

For example, the Chinese patent with publication number CN 102952038A discloses a synthetic method of o-toluoyl nitrile, but the cyanide reagent used therein is an aqueous solution of sodium cyanide or potassium cyanide, and the raw material o-toluoyl chloride Unstable in the presence of water, it is easy to react with water to generate o-toluic acid and HCl, causing a part of the loss of raw materials and reducing the yield; and, due to the excessive amount of cyanide reagent, the generated by-product sodium chloride and unreacted Aqueous solutions of sodium cyanide or potassium cyanide are mixed together to obtain a large amount of cyanide-containing and salt-containing wastewater, which increases the difficulty of post-treatment

[0004] In addition, as the Chinese patent with the publication number CN104387293A discloses a preparation method using hydrocyanic acid as a cyanation reagent, but it only has high atom economy from the perspective of chemical reaction, but if it is enlarged to In industrial production, the use of hydrocyanic acid gas is limited, and the requirements for production equipment are high and there are great safety hazards; the unreacted hydrocyanic acid and by-product HCl are blown out by nitrogen, and the by-product hydrochloric acid obtained after being absorbed by water There is a large amount of hydrocyanic acid mixed in it, which is highly dangerous and cannot be treated as an ordinary by-product, which is not conducive to environmental protection and also increases the safety risk in the process

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