65267-97-2Relevant academic research and scientific papers
Preparation method of 2,4-dichlorophenoxyacetic ester
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, (2019/01/08)
The invention provides a preparation method of 2,4-dichlorophenoxyacetic ester, wherein the preparation method includes the following steps: S1) carrying out a reaction of phenol and methyl chloroacetate under alkaline conditions to obtain methyl phenoxyacetate; S2) carrying out selective chlorination reaction of methyl phenoxyacetate with a chlorinating agent under the action of a catalyst A anda catalyst B to obtain 2,4-methyl dichlorophenoxyacetate, wherein the catalyst A is Lewis acid, and the catalyst B is C5-22 thioethers, thiazoles, isothiazoles and thiophenes or halogenated derivatives thereof; and S3) carrying out transesterification reaction of 2,4-methyl dichlorophenoxyacetate and alcohol under the action of a catalyst, to obtain 2,4-dichlorophenoxyacetic ester, wherein the alcohol is C2-20 alcohol. The selective chlorination reaction is carried out with methyl phenoxyacetate as a raw material, the selectivity of the reaction is improved, the loss of effective components isavoided, the yield of the effective components is greatly improved, and the three-waste treatment capacity, the three-waste treatment difficulty and the treatment cost are reduced.
Preparation method of 2,4-dichlorophenoxyacetic acid and salt thereof
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Paragraph 0127; 0129; 0131; 0133; 0135; 0137, (2019/01/06)
The invention provides a preparation method of 2,4-dichlorophenoxyacetic acid and a salt thereof, wherein the preparation method includes the following steps: S1) carrying out a reaction of phenol andchloracetic ester under alkaline conditions to obtain phenoxyacetic ester; S2) carrying out selective chlorination reaction of the phenoxyacetic ester with a chlorinating agent under the action of acatalyst A and a catalyst B to obtain 2,4-dichlorophenoxyacetic ester, wherein the catalyst A is Lewis acid, and the catalyst B is C5-22 thioethers, thiazoles, isothiazoles and thiophenes or halogenated derivatives thereof; and S3) carrying out hydrolysis reaction of 2,4-dichlorophenoxyacetic ester under acidic conditions to obtain 2,4-dichlorophenoxyacetic acid; or after 2,4-dichlorophenoxyaceticester is obtained, carrying out an alkaline hydrolysis reaction with an alkaline compound to obtain 2,4-dichlorophenoxyacetate. The production and use of 2,4-dichlorophenol with unpleasant odor are avoided, the production of dioxins is eliminated, the yield of products is improved, and the output of three wastes is greatly reduced.
Preparation method of phenoxycarboxylic acid choline salt
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Paragraph 0099; 0101, (2019/01/08)
The invention provides a preparation method of a phenoxycarboxylic acid choline salt, wherein the preparation method includes the steps: S1, carrying out condensation reaction of phenol or o-cresol with chlorocarboxylic ester in the presence of alkaline substances to obtain phenoxycarboxylic ester; S2, carrying out selective chlorination of the phenoxycarboxylic ester with a chlorinating agent inthe presence of a first catalyst and a second catalyst to obtain chlorobenzoxycarboxylic ester; and S3, after reaction of trimethylamine with ethylene oxide, adding the chlorophenoxycarboxylic acid ester, and carrying out alkaline hydrolysis reaction to obtain the phenoxycarboxylic acid choline salt. Compared with a conventional synthesis technology, the preparation method effectively avoids the production and use of chlorophenols with unpleasant odor, radically eliminates the production of highly toxic dioxins, and greatly improves the product quality and the operation environment of the production site; with phenol as the raw material, through condensation, selective chlorination and alkaline hydrolysis, the high-quality phenoxycarboxylic acid choline salt is obtained, the loss of effective ingredients is effectively avoided and the yield of the product is increased.
