Method for synthesizing 2-chlorobutyric acid

A technology of chlorobutyric acid and n-butyric acid, which is applied in the preparation of carboxylic acid anhydride, chemical recovery and other directions, can solve the problems such as the inability to recycle the catalyst, the by-product 3-chlorobutyric acid is too much, and the reaction time is long, so as to reduce excessive chlorine The effect of improving the environmental protection effect and high utilization rate

Inactive Publication Date: 2011-11-16
JIAXING BOYUAN BIO CHEM TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Although the conversion rate of this reaction is better (97%~99%), the by-product 3-chlorobutyric acid is more (...

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] 1) Add n-butyric acid and butyric anhydride in the reaction vessel, stir evenly at room temperature, the mass ratio of n-butyric acid and butyric anhydride is 1:0.5;

[0017] 2) continuous chlorine gas, the reaction temperature is controlled at 95 ° C, normal pressure, the reaction time is 5 hours, the mol ratio of the amount of chlorine to n-butyric acid is 2: 1 (during the reaction, check the conversion rate of n-butyric acid and control it at 85 %~95% to prevent over-chlorination);

[0018] 3) Add water equimolar to butyric anhydride, and hydrolyze it into n-butyric acid at 50°C under normal pressure; the hydrolyzed crude material contains 2-chlorobutyric acid, 3-chlorobutyric acid, n-butyric acid and other by-products. Detected by gas chromatography: 65% of 2-chlorobutyric acid, 33% of n-butyric acid, 0.99% of 3-chlorobutyric acid, 0.46% of 4-chlorobutyric acid, and 0.55% of others.

[0019] 4) The crude material is rectified to obtain 2-chlorobutyric acid with a c...

Embodiment 2

[0022] 1) Add n-butyric acid and butyric anhydride in the reaction vessel, stir evenly at room temperature, the mass ratio of n-butyric acid and butyric anhydride is 1:1;

[0023] 2) continuous chlorine gas, the reaction temperature is controlled at 90°C, normal pressure, the reaction time is 7 hours, the molar ratio of the amount of chlorine to n-butyric acid is 2.5: 1 (during the reaction, check the conversion rate of n-butyric acid and control it at 85 %~95% to prevent over-chlorination);

[0024] 3) Add water equimolar to butyric anhydride, and hydrolyze it into n-butyric acid at 50°C under normal pressure; the hydrolyzed crude material contains 2-chlorobutyric acid, 3-chlorobutyric acid, n-butyric acid and other by-products;

[0025] 4) The crude material is rectified to obtain 2-chlorobutyric acid with a content of more than 99%, and the yield of 2-chlorobutyric acid is 98%.

[0026] The rectification can also obtain n-butyric acid with a content of more than 99%, and ...

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Abstract

The invention discloses a method for synthesizing 2-chlorobutyric acid, which comprises the following steps that: n-butyric acid and liquid chlorine are reacted in the presence of butyric anhydride serving as a catalyst at 50 to 150 DEG C for 5 to 15 hours, namely chloride ions substitute hydrogen ions at position-2 of the molecules of butyric anhydride to form 2-chlorobutyric anhydride and then the 2-chlorobutyric anhydride reacts with n-butyric acid to form butyric anhydride and 2-chlorobutyric acid; and after reaction, the 2-chlorobutyric acid with a purity of over 99 percent can be obtained by rectification. In the invention, butyric anhydride is used as a catalyst, and by controlling the reaction temperature and chlorine content, the conversion rate can be kept between 85 and 95 percent, the by-products generated can be reduced, and excessive chlorination can be prevented; and after being hydrolyzed, the catalyst can be recycled, and unreacted n-butyric acid can be reclaimed by rectification and can be reused in subsequent production. In the invention, the used amount of chlorine is small, fewer byproducts are produced, the utilization rate of n-butyric acid is high, and the environment-protection effect is improved considerably.

Description

technical field [0001] The invention relates to a method for synthesizing organic acids, in particular to a method for synthesizing 2-chlorobutyric acid. Background technique [0002] There are many traditional processes for making 2-chlorobutyric acid, usually phosphorus and phosphorus chloride are used as catalysts, such as: n-butyric acid is used as raw material, phosphorus pentachloride is used as catalyst, and chlorine gas is passed through for chlorination reaction. Normal pressure, temperature control 150-200°C, reaction time 20-50h. After the reaction is completed, the crude material is rectified. The molar ratios of n-butyric acid, phosphorus pentachloride and liquid chlorine are 1:0.2~0.5:3~6 respectively. [0003] Although the conversion rate of this reaction is better (97%~99%), the by-product 3-chlorobutyric acid is more (5%~10%), the reaction time is longer, the temperature is higher, and the catalyst cannot be recycled and reused. solid waste. Contents of...

Claims

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Application Information

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IPC IPC(8): C07C53/19C07C51/083
CPCY02P20/584
Inventor 陈效宁王国庆王晓宇金文海张胜建
Owner JIAXING BOYUAN BIO CHEM TECH
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