Supercharge Your Innovation With Domain-Expert AI Agents!

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

Active Publication Date: 2019-08-09
SUZHOU KAIYUAN MINSHENG SCI & TECH CORP
View PDF8 Cites 6 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[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
[0006] In the patent CN10619305, R-2-phenoxypropionic acid is used as raw material and prepared by fermentation of Pseudomonas-1. This method is difficult to cultivate yeast, long reaction time, more waste water, and low production efficiency

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • R-(+)-2-(4-hydroxyphenoxy)propionic acid preparation method
  • R-(+)-2-(4-hydroxyphenoxy)propionic acid preparation method
  • R-(+)-2-(4-hydroxyphenoxy)propionic acid preparation method

Examples

Experimental program
Comparison scheme
Effect test

preparation example Construction

[0030] The present invention relates to a kind of preparation method of R-(+)-2-(4-hydroxyphenoxy)propionic acid, comprising the following steps:

[0031] 1) Mix the compound shown in Formula I and Formula II and a solvent in an inert gas environment, and heat for an alkylation reaction; wherein X is F, Cl, Br or I;

[0032]

[0033] 2) After the alkylation and alkylation reaction is completed, add an alkaline solution in a closed environment to adjust the pH to ≥ 8, and separate layers after stirring;

[0034] 3) Separate the lower layer product, add concentrated hydrochloric acid to adjust the pH<1, cool down and crystallize, and recrystallize to obtain R-(+)-2-(4-hydroxyphenoxy)propionic acid;

[0035] 4) Recycling the solvent for reuse.

[0036] According to the present invention, the alkylation reaction is specifically: carrying out the compound represented by formula I, aniline and its derivatives, and the compound represented by formula II according to an equivalent...

Embodiment 1

[0053] R-(+)-2-(4-hydroxyphenoxy)propionic acid is prepared in the presence of aniline and the aniline is recovered.

[0054] step 1

[0055] In 1000mL reaction flask, add p-chlorophenol (64.3g, 0.5mol, 1.0eq), aniline (372.4g, 4.0mol, 8.0eq) and S-2-hydroxypropionic acid (45.04g, 0.5mol, 1.0eq), Nitrogen was replaced three times, the temperature was raised to 50-70° C., and the reaction was kept for 4-6 hours. The conversion rate of S-2-hydroxypropionic acid monitored by HPLC was greater than 99.5%, and the reaction was completed. Cool down, add 30% liquid caustic soda, adjust pH ≥ 8, stir for 30 minutes to separate layers, separate the water layer and adjust pH < 1 with 31% hydrochloric acid, cool to below 10°C, crystallize and filter to obtain R-(+)-2- (4-hydroxyphenoxy)propionic acid crude product 94.5g (undried). The crude product was recrystallized with 94.5 g of water, filtered and dried to obtain 89.1 g of R-(+)-2-(4-hydroxyphenoxy)propionic acid, with a yield of 97....

Embodiment 2

[0059] R-(+)-2-(4-hydroxyphenoxy)propionic acid was prepared using recovered aniline.

[0060] step 1

[0061] Add p-chlorophenol (64.3g, 0.5mol, 1.0eq) to a 1000mL reaction flask, recover aniline (372.4g, 4.0mol, 8.0eq) and S-2-hydroxypropionic acid (45.04g, 0.5mol, 1.0eq) , replaced with nitrogen three times, heated up to 50-70° C., kept for 4-6 hours, and the conversion rate of S-2-hydroxypropionic acid monitored by HPLC was greater than 99.5%, and the reaction was completed. Cool down, add 30% liquid caustic soda, adjust pH ≥ 8, stir for 30 minutes to separate layers, separate the water layer and adjust pH < 1 with 31% hydrochloric acid, cool to below 10°C, crystallize and filter to obtain R-(+)-2- (4-hydroxyphenoxy) propionic acid crude product 93.7g (undried). The crude product was recrystallized with 93.7 g of water, filtered and dried to obtain 88.2 g of R-(+)-2-(4-hydroxyphenoxy)propionic acid, with a yield of 96.8% and a purity of 99.7%.

[0062] step 2

[0063] ...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

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.

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

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Applications(China)
IPC IPC(8): C07C59/125C07C51/367
CPCC07C51/367C07B2200/07C07C59/125Y02P20/582
Inventor 余志强徐剑锋曾淼孙思沈洁韦伟
Owner SUZHOU KAIYUAN MINSHENG SCI & TECH CORP
Features
  • R&D
  • Intellectual Property
  • Life Sciences
  • Materials
  • Tech Scout
Why Patsnap Eureka
  • Unparalleled Data Quality
  • Higher Quality Content
  • 60% Fewer Hallucinations
Social media
Patsnap Eureka Blog
Learn More

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic, Popular Technical Reports.

© 2025 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap|About US| Contact US: help@patsnap.com