Preparation technology of high-purity 2-methyl-4-chlorophenoxyacetic acid

A technology of chlorophenoxyacetic acid and preparation process, applied in the field of pesticides, can solve problems such as less than 10,000 tons

Inactive Publication Date: 2018-12-07
JIANGSU JIANGU CHEM
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  • Abstract
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Problems solved by technology

[0002] 2-Methyl-4-chlorophenoxyacetic acid is widely used in rice, wheat, corn, sorghum, sugarcane and non-cultivated land to control broad-leaved weeds. It is a mature product with no weed resistance, high effect and moderate price. With the modernization of agricultural production, the economic concepts of farmers’ friends have changed, and the use of herbicides has increased year by year. According to the statistics of the Ministry of Agriculture, the annual consumption of 2-methyl-4-chlorophenoxyacetic acid in China is about 50,000 tons, and the export volume is about 30,000 tons. The total production capacity of domestic manufacturers is less than 10,000 tons, and there is a large gap

Method used

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Embodiment Construction

[0014] The present invention will not be described below in conjunction with the embodiments.

[0015] The preparation process of high-purity 2-methyl-4-chlorophenoxyacetic acid comprises the following steps:

[0016] (4) Combining external circulation vacuum rectification and liquid-liquid stratification to reuse o-cresol in sodium o-cresol;

[0017] The product generated by the reaction of o-cresol and sodium hydroxide is sodium o-cresolate solution and excess o-cresol, and the o-cresol and water are removed by rectification under reduced pressure. Layered, o-cresol and water are recycled, and the solution in the bottom of the tower is circulated to the middle of the tower through a pump for recycling.

[0018] (5) Preparation of 2-methyl-4-chlorophenoxyacetic acid by reverse chlorination by external circulation solvent method;

[0019] Using 1,2-dichloroethane as a solvent, chlorine gas and 2-methylphenoxyacetic acid are respectively reversely added to the reactor for chl...

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Abstract

The invention discloses a preparation technology of high-purity 2-methyl-4-chlorophenoxyacetic acid, comprising the following steps: (1) combining outer circulation rectification under vacuum and liquid-liquid layering and reusing ortho-cresol in sodium o-cresolate; (2) preparing 2-methyl-4-chlorophenoxyacetic acid by outer cycling solvent-process reverse chlorination; and (3) conducting coiled tubing preparation of 2-methyl-4-chlorodimethylamine salt. COD value of water during the treatment process is lower than 100 ppm, there is almost no loss of extraction absorbents and the extraction absorbents can be recycled; and by resource treatment of tail gas, annual output of 0.5 ton of dichloroethane with purity being 98% and above and 0.24 ton of ortho-cresol with purity being 97% and above is achieved.

Description

technical field [0001] The invention relates to the technical field of pesticides, in particular to a preparation process of high-purity 2-methyl-4-chlorophenoxyacetic acid. Background technique [0002] 2-Methyl-4-chlorophenoxyacetic acid is widely used in rice, wheat, corn, sorghum, sugarcane and non-cultivated land to control broad-leaved weeds. It is a mature product with no weed resistance, high effect and moderate price. With the modernization of agricultural production, the economic concepts of farmers’ friends have changed, and the use of herbicides has increased year by year. According to the statistics of the Ministry of Agriculture, the annual consumption of 2-methyl-4-chlorophenoxyacetic acid in China is about 50,000 tons, and the export volume is about 30,000 tons. The total production capacity of domestic manufacturers is less than 10,000 tons, and the gap is relatively large. Contents of the invention [0003] Aiming at the problems in the background techno...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C51/00C07C51/41C07C59/70C07C37/66C07C37/70C07C37/74C07C39/07C07C209/00C07C211/04
CPCC07C51/00C07C37/66C07C37/685C07C37/70C07C37/74C07C51/412C07C209/00C07C59/70C07C39/07C07C211/04
Inventor 董良胜陆劲松杜莹
Owner JIANGSU JIANGU CHEM
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