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Crystallization-free technique for preparing phenylacetic acid from impurity-containing phenylacetate solution

A technology of phenylacetate and phenylacetic acid, which is applied in the fields of carboxylate preparation, separation/purification of carboxylic acid compounds, organic chemistry, etc. It can solve the problem of low production efficiency, unstable product quality and inconvenient drying in the water recrystallization method and storage and transportation, to achieve the effect of improving the production environment, low cost, and convenient use, storage and transportation

Active Publication Date: 2013-01-16
BLUESTAR LEHIGH ENG INST CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the low solubility of phenylacetic acid in water, the water recrystallization method has low production efficiency, high energy consumption and large amount of waste water; the disadvantage of organic solvent recrystallization method is that the solvent loss is large, the cost is high, and the product quality is unstable; the recrystallization method is first The crude phenylacetic acid crystals are precipitated from the solution, and then purified by secondary crystallization with water or an organic solvent. A volatile odor with foul odor is produced in the environment, which seriously affects the environmental quality

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] Embodiment 1, a kind of process of preparing phenylacetic acid from devitrification-free phenylacetate solution containing impurities comprises the following steps:

[0025] (1) Dilution: Dilute the impurity-containing phenylacetate solution prepared by the alkaline hydrolysis process of phenylacetonitrile or the benzyl chloride carbonylation synthesis process with deionized water to a concentration not higher than 500g / l; the phenylacetate solution It is one or a mixed solution of sodium phenylacetate solution, potassium phenylacetate solution and ammonium phenylacetate solution;

[0026] (2) Decolorization: the diluted phenylacetate solution is adjusted to pH 8.5 with inorganic acid, the temperature is controlled at 10°C, and activated carbon is added to stir for 2.0 hours to decolorize, and then filtered; the inorganic acid is selected from sulfuric acid, hydrochloric acid, nitric acid or phosphoric acid;

[0027] (3) Oxidation: adjust the pH value of the decoloriza...

Embodiment 2

[0032] Embodiment 2, a kind of process of preparing phenylacetic acid from devitrification-free phenylacetate solution containing impurities comprises the following steps:

[0033] (1) Dilution: Dilute the impurity-containing phenylacetate solution prepared by the alkaline hydrolysis process of phenylacetonitrile or the benzyl chloride carbonylation synthesis process with deionized water to a concentration not higher than 500g / l; the phenylacetate solution It is one or a mixed solution of sodium phenylacetate solution, potassium phenylacetate solution and ammonium phenylacetate solution;

[0034] (2) Decolorization: adjust the pH value of the diluted phenylacetate solution to 9.5 with inorganic acid, control the temperature at 60°C, add activated carbon and stir for 2.5 hours to decolorize, then filter; the inorganic acid is selected from sulfuric acid, hydrochloric acid, nitric acid or phosphoric acid;

[0035] (3) Oxidation: adjust the pH value of the decolorized filtrate t...

Embodiment 3

[0040] Embodiment 3, a kind of process of preparing phenylacetic acid from devitrification-free phenylacetate solution containing impurities comprises the following steps:

[0041] (1) Dilution: Dilute the impurity-containing phenylacetate solution prepared by the alkaline hydrolysis process of phenylacetonitrile or the benzyl chloride carbonylation synthesis process with deionized water to a concentration not higher than 500g / l; the phenylacetate solution It is one or a mixed solution of sodium phenylacetate solution, potassium phenylacetate solution and ammonium phenylacetate solution;

[0042] (2) Decolorization: the diluted phenylacetate solution is adjusted to pH 9.0 with inorganic acid, the temperature is controlled at 30°C, and activated carbon is added to stir for 2.2 hours to decolorize, and then filtered; the inorganic acid is selected from sulfuric acid, hydrochloric acid, nitric acid or phosphoric acid;

[0043](3) Oxidation: adjust the pH value of the decolorized...

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Abstract

The invention relates to a crystallization-free technique for preparing phenylacetic acid from an impurity-containing phenylacetate solution, which comprises the following steps: adding water to dilute impurity-containing phenylacetate, adding active carbon for decolorization, and filtering; regulating the pH value of the filtrate, and adding an oxidizer to remove impurities; acidifying the solution subjected to impurity removal, heating, and discharging understratum wastewater; adding water to wash the supernatant oil layer, and heating to carry out vacuum dehydration; and pelletizing the dehydrated molten phenylacetic acid in a pelletizer, and packaging to obtain the finished phenylacetic acid product. The invention has the advantages of simple technique, low cost and high product quality, is convenient for use, storage and transportation, enhances the production efficiency, and improves the production environment.

Description

technical field [0001] The invention relates to a production process of organic chemical products, in particular to a process for preparing phenylacetic acid from impurity-containing phenylacetate solution without crystallization. Background technique [0002] Phenylacetic acid is an important organic chemical raw material. The pharmaceutical industry is mainly used in the production of penicillin, dimethazole and other drugs; phenylacetic acid is chlorinated and esterified to obtain ethyl α-chlorophenylacetate, which is used for broad-spectrum organophosphorus insecticides Daofengsan and ethyl rice The production of Fengsan itself is also a pesticide plant growth stimulant; phenylacetic acid has a sweet honey taste at low concentrations, and phenylacetic acid and its esters are widely used in the perfume industry as fixatives or modifiers. [0003] The production processes of phenylacetic acid mainly include acidic hydrolysis of benzyl nitrile, alkaline hydrolysis of benzy...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C57/32C07C51/02C07C51/42
Inventor 程辉董自斌相振昌
Owner BLUESTAR LEHIGH ENG INST CO LTD
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