Method for preparing methyl R-(+)-2-(4-hydroxyphenoxy)propionate

A technology of hydroxyphenoxy and methyl propionate, which is applied in the field of compound preparation, can solve the problems of reducing reaction efficiency, prolonging reaction time, and low reaction yield, achieving high reaction rate, reducing the amount of waste acid, and increasing yield Effect

Inactive Publication Date: 2018-06-08
SUZHOU KAIYUAN MINSHENG SCI & TECH CORP
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Problems solved by technology

[0004] Synthesis of R-(+)-2-(4-hydroxyphenoxy)propionic acid methyl ester by esterifying R-(+)-2-(4-hydroxyphenoxy)propionic acid with methanol Reaction, known reaction has: 1, direct esterification; Reaction yield is low; 2, carry out esterification under the action of catalyst, catalyst has: sulfuric acid, hydrogen chloride, lead catalyst, need to add catalyst, prolonged reaction time, The reaction efficiency is reduced and, if lead-based catalysts are used, lead will bring heavy metal ions along with the wastewater or the wastewater contains a large amount of methanol, making the COD in the wastewater higher
3. It is necessary to use a solvent for dehydration during the reaction to promote the forward progress of the esterification reaction, such as toluene, etc. However, if the solvent is used for dehydration, the solvent will remain in the wastewater and affect the environment

Method used

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  • Method for preparing methyl R-(+)-2-(4-hydroxyphenoxy)propionate
  • Method for preparing methyl R-(+)-2-(4-hydroxyphenoxy)propionate

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preparation example Construction

[0034] The present invention relates to the technical scheme of the present invention is to adopt a kind of preparation method of R-(+)-2-(4-hydroxyphenoxy) methyl propionate, comprising:

[0035] 1) Mix the compounds shown in formula I, methanol and formula II in a closed environment, and heat to reflux for esterification;

[0036]

[0037] According to the present invention, in order not to add catalyst in reaction process, and make reaction form catalyst, the present invention has preferably used the organic matter that contains sulfur, preferably uses dimethyl sulfate, in reaction process, a methyl alcohol and the compound shown in formula I carry out Esterification reaction, and the generated water can impel the hydrolysis of dimethyl sulfate to form sulfuric acid and methanol, and sulfuric acid and methanol can promote the esterification reaction of the compound shown in formula I and methanol to proceed forward, improving the conversion of the reaction Rate. Accordi...

Embodiment 1

[0059]Dimethyl sulfate (32g; 0.5eq), methanol (105.6g; 6eq) and R-(+)-2-(4-hydroxyphenoxy)propionic acid (91g; 1eq) were added in a 500mL reaction flask, and the The reaction was carried out under reflux for 4-6 hours, and the esterification conversion rate monitored by HPLC was greater than 99.5%, and the reaction was completed. Lower the temperature, start to concentrate methanol under reduced pressure at 30°C, control the vacuum degree <-0.095MPa, concentrate at below 55°C, recover the methanol for use, add toluene (182g, twice the raw material) until it cannot evaporate, and cool down to 30-40°C , continue to distill methanol under reduced pressure, detect methanol<1% (GC: area normalization method), wash the sulfuric acid produced by the reaction in the toluene layer with 5% sodium bicarbonate solution (50mL) and destroy monomethyl sulfate, wash and divide layer, then concentrate the organic layer to 165g, cool down at 0°C to crystallize for 2 hours, centrifuge, and dry t...

Embodiment 2

[0061] Dimethyl sulfate (13g; 0.2eq), methanol (105.6g; 6eq) and R-(+)-2-(4-hydroxyphenoxy)propionic acid (91g; 1eq) were added in a 500mL reaction flask, and the The reaction was carried out under reflux for 4-6 hours, and the esterification conversion rate monitored by HPLC was greater than 99.5%, and the reaction was completed. Lower the temperature, start to concentrate methanol under reduced pressure at 30°C, control the vacuum degree <-0.095MPa, concentrate at below 55°C, recover the methanol for use, add toluene (182g, twice the raw material) until it cannot evaporate, and cool down to 30-40°C , continue to distill methanol under reduced pressure, detect methanol<1% (GC: area normalization method), wash the sulfuric acid produced by the reaction in the toluene layer with 5% sodium bicarbonate solution (50mL) and destroy monomethyl sulfate, wash and divide Then concentrate the organic layer to 165g, cool down at 0°C for crystallization for 2 hours, centrifuge, and dry th...

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Abstract

The first problem to be improved in the invention is to provide a method for preparing methyl R-(+)-2-(4-hydroxyphenoxy)propionate. Dimethyl sulfate and water, methanol and sulfuric acid generated during an esterification reaction continuously catalyze the reaction, so the esterification conversion rate is improved to above 99.5%, and the average esterification yield of the whole process is about99%; and no catalyst is excessively added in the reaction process, and a reaction system is sealed, so the environment is protected. The reaction rate of methanol in the system is high, and the methanol can be repeatedly used, so the problem of low conversion rate of pure methanol when reacted under the action of the catalyst is improved, the yield is increased, and the cost is reduced. An alkali-washed mother liquor can be recycled to solve the problem of high COD of alkali washing wastewater during dehydration, so the wastewater treatment cost is reduced. Experiments in the invention show that the average yield of the method is 99%, and the purity of the product is 99% or more.

Description

technical field [0001] The present invention relates to the field of compound preparation, in particular to one. The preparation method of R-(+)-2-(4-hydroxyphenoxy) methyl propionate. Background technique [0002] Clodinafop propargyl is also known as (R)-2-[4-(5-chloro-3-fluoro-2-pyridyloxy)phenoxy]propargyl propargyl; top herbicide, its original drug is milky white crystal , Odorless, tasteless, mainly used for the control of wild oats, kangaroos, oats, ryegrass, common bluegrass, foxtail and so on. [0003] Methyl R-(+)-2-(4-hydroxyphenoxy)propionate is an important intermediate in the synthesis of clodinafop-propargyl, white or off-white crystalline powder, with a melting point of 145-148°C. [0004] Synthesis of R-(+)-2-(4-hydroxyphenoxy)propionic acid methyl ester by esterifying R-(+)-2-(4-hydroxyphenoxy)propionic acid with methanol Reaction, known reaction has: 1, direct esterification; Reaction yield is low; 2, carry out esterification under the action of catalys...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C67/11C07C69/736C07C67/48
CPCC07B2200/07C07C67/11C07C67/48C07C69/736
Inventor 余志强徐剑锋曾淼沈洁孙思韦伟
Owner SUZHOU KAIYUAN MINSHENG SCI & TECH CORP
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