Preparation method to recycle pyribenzoxim byproduct dicyclohexylurea

Abstract

The invention discloses a preparation method to recycle pyribenzoxim byproduct dicyclohexylurea and belongs to the field of agricultural chemistry. The byproduct N,N'-dicyclohexylurea is used as a rawmaterial; N,N'-dicyclohexylurea and organic phosphorus catalyst are heated to 140-160 for reacting; the temperature is then lowered to 60-80 DEG C for reacting; after reacting, the catalyst is recycled by filtering, and filtrate is distilled under reduced pressure; distillate at 125-140 DEG C (6-8 mmHg) is collected and cooled to obtain white solid, N,N'-dicyclohexylcarbodiimide; the highest yield reaches 88.2%, and purity reaches 98.4%. The preparation method is efficient, environmentally friendly, sustainable, and suitable for industrial production; the preparation method has the advantagesof good energy efficiency, low consumption, lower pollutant emission and the like, allows a preparation technique of recycling byproducts of pyribenzoxim production process to be implemented, and meets the green manufacturing principle.

Description

technical field [0001] The invention relates to a method for preparing dicyclohexylcarbodiimide (DCC) by recovering and applying the by-product N,N'-dicyclohexylurea (DCU) produced in the production process of pyrimidin saflufenacil, in particular to a method utilizing The method for preparing DCC by using DCU as a raw material belongs to the field of agricultural chemistry. Background technique [0002] DCC (Dicyclohexylcarbodiimide), that is, N, N'-dicyclohexylcarbodiimide, is a dehydrating agent commonly used in industries and laboratories to synthesize aldehydes, ketones, amino acids, acid anhydrides, esters and other compounds, and is widely used in medicine and pesticides , materials and other fine chemical industries. With the rapid development of modern agriculture, the market demand for DCC is more and more strong. Zhang Guangyou and others reported the method of using dicyclohexyl thiourea method to synthesize DCC, that is, reacting cyclohexylamine and carbon dis...

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Problems solved by technology

[0003] The above-mentioned methods all have safety hazards, or use phosphorus pentoxide or phosphorus oxychloride as raw materials, or produce hydrogen sulfide gas with the smell of rotten eggs in the process, all of which have serious safety problems, seriously pollute the environment, and are not compatible with green manufacturing. match

[0004] Our research group invented a method for preparing saflufenacil in the next step of catalyst action by using bispyribac and benzophenone oxime (Xu Defeng, A preparation method of saflufenacil, a pyrimidine salicylic acid herbicide , Chinese invention patent: ZL 201310228135.9), during the production process, a large amount of by-product DCU is also generated, if not treated, it will become solid waste, affecting the sustainable production of saflufenacil

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