Synthesis method for 2, 5-dimethyl phenylacetic acid

A technology of dimethylphenylacetic acid and a synthetic method, which is applied in the field of compound preparation, can solve problems such as low yield of synthetic products, highly toxic reaction raw materials, etc., and achieve the effects of cheap raw materials, easy large-scale industrial production, and simple method and process

Inactive Publication Date: 2014-05-21
SOUTHEAST UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The purpose of this invention is to provide a kind of synthetic method of 2,5-dimethylphenylacetic acid, and this synthetic method is economical, environment-friendly, efficient, solves the highly toxic reaction raw material in existing 2,5-dimethylphenylacetic acid synthesis, produces Problems such as toxic intermediate products and low yield of synthetic products

Method used

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  • Synthesis method for 2, 5-dimethyl phenylacetic acid
  • Synthesis method for 2, 5-dimethyl phenylacetic acid

Examples

Experimental program
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Effect test

Embodiment 1

[0034] (1) Take 16g of p-xylene and 4.5g of paraformaldehyde in a 250ml four-neck bottle, add 75ml of glacial acetic acid and stir well. At room temperature, while vigorously stirring at 1000rpm, another 12ml of 47% (wt) hydrogen bromide aqueous solution was added dropwise to the mixture, and the dropwise addition was completed in about 1 hour. Then, the temperature was raised to 60°C, and the reaction was refluxed for 4 hours. After cooling to room temperature, the solution was poured into 300ml of distilled water, allowed to stand for liquid separation, and the organic phase was separated, dried with anhydrous sodium sulfate, and filtered. The filtrate was distilled under reduced pressure (vacuum degree: 0.09 MPa, temperature: 50°C), and after glacial acetic acid and unreacted reactants were evaporated, 12.34 g of 2,5-dimethylbenzyl bromide was obtained with a yield of 62%.

[0035] (2) Add 10.0g 2,5-dimethylbenzyl bromide, 2g sodium hydroxide (2,5-dimethylbenzyl bromide:sod...

Embodiment 2

[0037] (1) Take 16g of p-xylene and 4.5g of paraformaldehyde in a 250ml four-neck bottle, add 75ml of glacial acetic acid and stir well. At room temperature, while vigorously stirring at 1500rpm, another 17ml of 47% (wt) hydrogen bromide aqueous solution was added dropwise to the mixture, and the dropwise addition was completed in about 1 hour. The temperature was raised to 70°C, and the reaction was refluxed for 6 hours. After cooling to room temperature, the solution was poured into 300ml of distilled water, allowed to stand for liquid separation, and the organic phase was separated, dried with anhydrous sodium sulfate, and filtered. The filtrate was distilled under reduced pressure (vacuum degree: 0.08MPa, temperature: 60°C), and after glacial acetic acid and unreacted reactants were distilled off, 21.66 g of 2,5-dimethylbenzyl bromide was obtained with a yield of 74%.

[0038] (2) Add 10.0g 2,5-dimethylbenzyl bromide, 2.4g sodium hydroxide (2,5-dimethylbenzyl bromide:sodiu...

Embodiment 3

[0040] (1) Take 16g of p-xylene and 4.5g of paraformaldehyde in a 250ml four-neck bottle, add 75ml of glacial acetic acid and stir well. At room temperature, while stirring vigorously at 500rpm, another 14ml of 47% (wt) hydrogen bromide aqueous solution was added dropwise to the mixture, and the dropwise addition was completed in about 1 hour. Then, the temperature was raised to 80°C, and the reaction was refluxed for 8 hours. After cooling to room temperature, the solution was poured into 300ml of distilled water, allowed to stand for liquid separation, and the organic phase was separated, dried with anhydrous sodium sulfate, and filtered. The filtrate was distilled under reduced pressure (vacuum degree: 0.09 MPa, temperature: 60°C), and after glacial acetic acid and unreacted reactants were evaporated, 16.13 g of 2,5-dimethylbenzyl bromide was obtained with a yield of 68%.

[0041] (2) Add 10.0g 2,5-dimethylbenzyl bromide, 3g sodium hydroxide (2,5-dimethylbenzyl bromide:sodi...

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Abstract

The invention discloses a synthesis method for 2, 5-dimethyl phenylacetic acid. Paraxylene is taken as the raw material to generate 2, 5-dimethyl benzyl bromide through bromine methylation, then the 2, 5-dimethyl benzyl bromide and CO generate carbonylation to generate 2, 5-dimethyl phenylacetic acid. The synthesis method uses cheap raw material, is simple and convenient to operate, is applicable to industrial production in a large scale, and has high application value. The synthesis method adopts CO and a catalyst for carbonylation, so that the reaction processes are shortened, three wastes are greatly reduced, and the energy consumption is also lowered as the processes are shortened.

Description

technical field [0001] The invention relates to the field of compound preparation, in particular to a method for synthesizing 2,5-dimethylphenylacetic acid. Background technique [0002] Spirotetramat is so far the only modern insecticide with bidirectional systemic conduction in xylem and phloem. The compound can move up and down throughout the plant, reaching the foliage and bark, thereby controlling pests such as those hidden on the inner leaves of lettuce and cabbage and on the bark of fruit trees. This unique systemic property protects new stems, leaves and roots from the growth of pest eggs and larvae. Two-way systemic conductivity means that pests have no safe place to hide, and the control effect is more thorough. Another feature is its long-lasting effect, which can provide effective control for up to 8 weeks. 2,5-Dimethylphenylacetic acid is a key intermediate for the synthesis of spirotetramat, and it is also an important fine chemical intermediate, widely used...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C57/30C07C51/02C07C22/04C07C17/32
CPCC07C51/02C07C17/32C07C51/14C07C57/30C07C22/04
Inventor 肖国民王中豪丁军露牛磊薛志君黄兵
Owner SOUTHEAST UNIV
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