- Preparation method of phenoxycarboxylate herbicide
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The invention provides a preparation method of a phenoxycarboxylate herbicide, wherein the preparation method includes the steps: S1, carrying out condensation reaction of phenol or o-cresol with chlorocarboxylic ester under the action of alkaline substances to obtain phenoxycarboxylic ester, wherein chlorocarboxylic ester has the general formula of ClR1COOR, R1 is C1-3 alkylene or alkylidene, R is C1-10 alkyl of or C3-10 cycloalkyl; and S2, under the action of a first catalyst and a second catalyst, carrying out selective chlorination of the phenoxycarboxylic ester with a chlorinating agent to obtain the chlorophenoxycarboxylic ester represented by the formula I, R3 is H, Cl or CH3, the first catalyst is selected from Lewis acid, and the second catalyst is selected from C5-22 thioether, thiazole, isothiazole or thiophene compounds; and S3, mixing chlorophenoxycarboxylic ester with an alkaline compound, and carrying out alkaline hydrolysis to obtain the phenoxycarboxylate herbicide. The preparation method can improve the product quality and production operation environment, and has low quantity of three wastes.
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Paragraph 0099; 0102
(2019/01/08)
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