R-(+)-2-(4-hydroxyphenoxy)propionic acid preparation method

A technology of hydroxyphenoxy and propionic acid, applied in the field of preparation of R--2-propionic acid, can solve the problems of low production efficiency, long reaction time, difficulty in yeast culture, etc., so as to reduce production costs and avoid polyphenols. Excessive alkylation of impurities, beneficial effect on environmental protection
CN110105201AActive Publication Date: 2019-08-09SUZHOU KAIYUAN MINSHENG SCI & TECH CORP
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
SUZHOU KAIYUAN MINSHENG SCI & TECH CORP
Publication Date
2019-08-09

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Abstract

The technical scheme of the invention adopts a R-(+)-2-(4-hydroxyphenoxy)propionic acid preparation method, which comprises: mixing a raw material compound and a solvent in an inert gas environment, heating, and carrying out an alkylation reaction; after completing the alkylation hydrocarbonization reaction, adding an alkaline solution in a closed environment to adjust the pH value of more than orequal to 8, stirring, and layering; separating to obtain a lower layer product, adding concentrated hydrochloric acid to adjust the pH value of less than 1, carrying out cooling precipitation, and re-crystallizing R-(+)-2-(4-hydroxyphenoxy)propionic acid; and recoverying the solvent for recycling. According to the present invention, the preparation method has characteristics of high raw materialconversion rate, high product purity, mild conditional and recycling of raw materials.
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Description

technical field

[0001] The invention relates to the field of compound preparation, in particular to a preparation method of R-(+)-2-(4-hydroxyphenoxy)propionic acid. Background technique

[0002] R-(+)-2-(4-Hydroxyphenoxy) propionic acid is important for the synthesis of aryloxypropionic acid herbicides such as thiafen-prop, haloxyfop-methyl, clodinafop-propargyl and high-efficiency clodinone. Intermediate, white or off-white crystal powder, melting point 143-147°C.

[0003] In the patent EP352168, it is proposed to prepare R-(+)-2-(4-hydroxyphenoxy) propionic acid with excess hydroquinone and s-2-halogenated propionic acid. This technology has two problems: one is Excessive alkylation of hydroquinone; the second is the oxidation of hydroquinone. A complex purification scheme is provided in EP352168.

[0004] In the patent CN100422129, the scheme of recovering excess hydroquinone with lye is adopted, and the use of reducing agent sodium bisulfite is increased at the same ...

Claims

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