Probenazole production process

Abstract

The invention discloses a probenazole production process, comprising the steps of: carrying out a condensation reaction on lactic acid and o-phenylenediamine in hydrochloric acid water solution; regulating pH to obtain 2-alpha-hydroxyethyl benzimidazole; putting into a container using acetone and sulfuric acid as solvents for oxidization with potassium permanganate; extracting, desolventizing and drying to obtain 2- acetyl benzimidazole; putting into a container using glacial acetic acid as a solvent to be brominated with bromne; drying a filtering cake to make 2- Dibromo-acetyl benzimidazole hydrobromide; finally cyclize with formamide and phosphorus pentasulfide in a container using ethyl acetate as a solvent; purifying; and regulating the pH to obtain probenazole, the content of which is larger than or equal to 99%. The production process reduces the cost and risks of safety environmental protection, reduces environmental pollution, enhances production efficiency, enables the whole reaction process to execute at normal temperature and pressure, and has mild reaction condition and stable reaction yield of each step. The total yield counted by the o-phenylenediamine is above 75%.

Description

technical field [0001] The invention relates to a production process of pesticides, in particular to a production process of fungicides. Background technique [0002] The current production process of thiabendazole is: use pyruvic acid to react with thioformamide after bromination reaction, then carry out condensation reaction with o-phenylenediamine, and adjust the pH to obtain thiabendazole. The yield of this process is low, and the total yield can only reach 48% in terms of o-phenylenediamine; the cost is high, and pyruvic acid is expensive, and it cannot be purchased in China; the process is unsafe and pollutes the environment. At this time, the temperature is required to be above 230°C. Under this temperature condition, o-phenylenediamine is easily oxidized. The whole process needs to be protected by nitrogen gas. Therefore, the whole production process is unsafe, the operation is difficult and dangerous, and it also pollutes the environment. Contents of the invention...

AI Technical Summary

Problems solved by technology

The yield of this process is low, and the total yield can only reach 48% in terms of o-phenylenediamine; the cost is high, and pyruvic acid is expensive, and it cannot be purchased in China; the process is unsafe and pollutes the environment. At this time, the temperature is required to be above 230°C. Under this temperature condition, o-phenylenediamine is easily oxidized, and the whole process must be protected by nitrogen gas. Therefore, the entire production process is unsafe, difficult to operate, highly dangerous, and pollutes the environment.