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DL-mandelic acid preparation process

A mandelic acid and process technology, applied in the field of mandelic acid preparation, can solve the problems of difficult separation of benzoic acid, high raw material cost, low yield and the like, and achieve the effects of high product optical purity, reduced raw material price, and improved product quality

Inactive Publication Date: 2017-07-28
枣阳市残联福利生物化工厂
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Wherein the benzaldehyde phase-transfer catalytic method has mild reaction conditions, but under the action of alkali, benzaldehyde is prone to disproportionation reaction, generating benzoic acid which is difficult to separate; the raw material cost of the glyoxylic acid method is high, and the yield is low; unnecessary waste is caused, To this end, we propose a process for the preparation of DL-mandelic acid

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] The present invention proposes a kind of technique for preparing DL-mandelic acid, comprises the steps:

[0022] S1. Select benzaldehyde, catalyst, sodium hydroxide and raw materials, and store the raw materials in a sealed manner;

[0023] S2. Add benzaldehyde and sodium hydroxide into the three-necked bottle with reflux and stirring, and the three-necked bottle is sterilized, and the temperature of the three-necked bottle is kept at 45 degrees Celsius, and slowly move into the three-necked bottle. Ionized water , and stirring at the same time;

[0024] S3, after reacting for 45s, slowly add dichloroacetophenone dropwise, and the temperature in the dropping process is controlled at 50 degrees Celsius. After the dropwise addition is completed, move to an environment of 65 degrees Celsius for 50 minutes, thereby generating a mixed solution, to Add hydrogen cyanide gas to the mixed solution again, and react at the same temperature for 30s again;

[0025] S4, adding an a...

Embodiment 2

[0036] The present invention proposes a kind of technique for preparing DL-mandelic acid, comprises the steps:

[0037] S1. Select benzaldehyde, catalyst, sodium hydroxide and raw materials, and store the raw materials in a sealed manner;

[0038] S2. Add benzaldehyde and sodium hydroxide into the three-necked bottle with reflux and stirring, and the three-necked bottle is sterilized, and the temperature of the three-necked bottle is kept at 50 degrees Celsius, and slowly move into the three-necked bottle. Ionized water , and stirring at the same time;

[0039] S3, after reacting for 50s, slowly add dichloroacetophenone dropwise, and control the temperature in the dropping process at 53 degrees Celsius. After the dropwise addition is completed, move to an environment of 65 degrees Celsius and place it for 51 minutes, thereby generating a mixed solution. Add hydrogen cyanide gas to the mixed solution again, and react at the same temperature for 35s again;

[0040] S4, adding ...

Embodiment 3

[0051] The present invention proposes a kind of technique for preparing DL-mandelic acid, comprises the steps:

[0052] S1. Select benzaldehyde, catalyst, sodium hydroxide and raw materials, and store the raw materials in a sealed manner;

[0053] S2. Add benzaldehyde and sodium hydroxide into the three-necked bottle with reflux and stirring, and the three-necked bottle is sterilized, and the temperature of the three-necked bottle is kept at 55 degrees Celsius, and slowly move into the three-necked bottle. Ionized water , and stirring at the same time;

[0054] S3, after reacting for 55s, slowly add dichloroacetophenone dropwise, and control the temperature in the dropping process at 57 degrees Celsius. After the dropwise addition is completed, move to an environment of 65 degrees Celsius and place it for 53 minutes, thereby generating a mixed solution. Add hydrogen cyanide gas to the mixed solution again, and react at the same temperature for 40 seconds;

[0055] S4, adding...

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Abstract

The invention discloses a DL-mandelic acid preparation process. The DL-mandelic acid preparation process comprises the following steps: adding benzaldehyde and sodium hydroxide into a three-neck bottle having backflowing and stirring functions, keeping the temperature of the three-neck bottle to 45-60 DEG C, slowly adding ionized water into the three-neck bottle, then slowly adding dichloroacetophenone dropwise, moving to the environment of 65 DEG C to place for 50-55 minutes so as to generate a mixed solution, adding a hydrogen cyanide gas into the mixed solution again, reacting at the same temperature again for 30-45 seconds, adding an acid solution into the mixed solution until a crystal overflows, adding a catalyst for multiple times to obtain a white crystal, adding water to dissolve the white crystal, adding an activated carbon to decolorize, filtering, enabling the solution to recrystallize at the environment of 30-35 DEG C, centrifuging and drying to obtain a finished product, namely the DL-mandelic acid. The cost of the raw materials is effectively reduced, the optical purity of the product is higher, and the product quality is greatly improved.

Description

technical field [0001] The invention relates to the technical field of mandelic acid preparation, in particular to a process for preparing DL-mandelic acid. Background technique [0002] Mandelic acid, also known as mandelic acid, is an intermediate in organic synthesis and a drug for oral treatment of urinary tract infections. DL-mandelic acid is the most important member of mandelic acid. DL-mandelic acid (hydroxyphenylacetic acid) is an important pharmaceutical intermediate and dye intermediate. Its synthesis methods mainly include benzaldehyde phase transfer catalysis, ethyl Aldehydic method, acetophenone method and benzaldehyde cyanation method. Wherein the benzaldehyde phase-transfer catalytic method has mild reaction conditions, but under the action of alkali, benzaldehyde is prone to disproportionation reaction, generating benzoic acid which is difficult to separate; the raw material cost of the glyoxylic acid method is high, and the yield is low; unnecessary waste ...

Claims

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Application Information

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IPC IPC(8): C07C59/50C07C51/08C07C45/63C07C49/80
CPCC07C51/08C07C45/63C07C253/08C07C59/50C07C255/36C07C49/80
Inventor 曹亮
Owner 枣阳市残联福利生物化工厂
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