Preparation method of phenoxycarboxylic acid herbicides
申请人:SHANDONG RAINBOW BIOTECH CO., LTD.
公开号:US11040933B2
公开(公告)日:2021-06-22
Disclosed is a preparation method of phenoxycarboxylic acid herbicides. The preparation method comprises the following steps. S1: mixing an anhydrous phenol and a basic substance with a chloro-substituted carboxylic acid ester and performing a one-pot condensation reaction in an anhydrous system to obtain a phenoxycarboxylic acid ester. The chloro-substituted carboxylic acid ester is represented by the formula ClR1COOR, in which R1 is a C1-3 alkanediyl or alkylidene group, R is a C1-10 alkyl group or a C3-10 cycloalkyl group; S2: the phenoxycarboxylic acid ester undergoes selective chlorination with a chlorinating agent in the presence of a first catalyst and a second catalyst to obtain a chloro-substituted phenoxycarboxylic acid ester; and S3: the chloro-substituted phenoxycarboxylic acid ester undergoes an acid hydrolysis reaction to obtain a phenoxycarboxylic acid herbicide represented by formula I, in which R3 is H, Cl or CH3.
Provided is a method for producing a chlorophenoxycarboxylate, comprising the following steps of: a phenoxycarboxylate under actions of a catalyst A and a catalyst B performing a selective chlorination of a chlorinating agent at a 2-position and/or a 4-position to obtain the chlorophenoxycarboxylate; the catalyst A is a Lewis acid; and the catalyst B has the following structure: R1′—S—R2′. The present disclosure redesigns the process route, and finely screens the catalyst and the chlorinating agent, thereby effectively improving the chlorination selectivity while avoiding the loss of the active ingredient, and the content of the obtained chlorophenoxycarboxylate can reach more than 98.5%, and the yield can reach more than 99%.
本发明提供了一种生产氯苯氧羧酸酯的方法,包括以下步骤:苯氧羧酸酯在催化剂 A 和催化剂 B 的作用下,在 2 位和/或 4 位上对氯化剂进行选择性氯化,以获得氯苯氧羧酸酯;催化剂 A 是路易斯酸;催化剂 B 具有以下结构:R1′-S-R2′。本发明重新设计了工艺路线,对催化剂和氯化剂进行了精细筛选,从而在避免有效成分损失的同时,有效提高了氯化选择性,得到的氯苯氧羧酸酯含量可达98.5%以上,收率可达99%以上。
[EN] METHOD FOR PREPARING PHENOXY CARBOXYLIC ACID HERBICIDE<br/>[FR] PROCÉDÉ DE PRÉPARATION D'UN HERBICIDE À BASE D'ACIDE PHÉNOXYCARBOXYLIQUE<br/>[ZH] 一种苯氧羧酸类除草剂的制备方法
[EN] PREPARATION METHOD OF PHENOXYCARBOXYLIC ACID HERBICIDES<br/>[FR] PROCÉDÉ DE PRÉPARATION D'HERBICIDES À BASE D'ACIDE PHÉNOXYCARBOXYLIQUE<br/>[ZH] 一种苯氧羧酸类除草剂的制备方法