3-hydroxyacetophenone synthesis method

Abstract

The invention provides a 3-hydroxyacetophenone synthesis method. The method includes the steps that 3-hydroxybenzoic acid is subjected to hydroxyl protection through an esterification or etherification reaction, then a chloroformylation reaction and an alkylation reaction are conducted, finally hydrolysis is conducted, and the 3-hydroxyacetophenone is obtained. According to the method, raw materials are cheap, easy to obtain and wide in source, high-temperature and high-pressure operation does not exist, equipment requirement is low, and equipment investment is low; peroxide, heavy nitride and the like do not exist, and high safety is achieved; compared with a nitration-iron powder reduction-diazotization route commonly adopted in the nation, the synthesis method has huge environment-friendly advantages. Besides, according to the method, the amount of wastewater is less than 5% that of an original process, the total route yield is 90%, and the method has huge technological advantages.

Description

technical field

[0001] The invention belongs to the field of chemical synthesis, and in particular relates to a synthesis method of 3-hydroxyacetophenone. Background technique

[0002] 3-Hydroxyacetophenone, also known as m-hydroxyacetophenone, m-hydroxyacetophenone, 3-hydroxyacetophenone, 3-acetylphenol, m-acetylphenol, 3-hydroxyacetylketone, etc., is the synthesis of phenylephrine Intermediates are in great demand in the market. The chemical structure of 3-hydroxyacetophenone is shown below:

[0003]

[0004] At present, the main synthetic methods of 3-hydroxyacetophenone include the following:

[0005] 1) The process route generally adopted by enterprises is to use acetophenone as the starting material, and to obtain m-nitroacetophenone through meta-nitration with mixed acid under the condition of -10~0°C, and crystallize and separate in ice water to obtain m-nitrobenzene Crude ethyl ketone, add the crude product to iron powder and hydrochloric acid system for reduc...

Examples

Embodiment 1

[0057]

[0058] Step (1): Add 50g of 3-hydroxybenzoic acid, 67g of acetic anhydride and 0.35g of concentrated sulfuric acid to the reaction vessel, heat up to 100°C under stirring and react for 30 minutes. After the reaction is over, distill under reduced pressure Removal of the solvent gave 64.5 g of 3-acetoxybenzoic acid (crude) as a white solid.

[0059] Step (2): Add 50 g of 3-acetoxybenzoic acid and 725 ml of toluene as a reaction solvent to the reaction vessel, then slowly add 56 g of thionyl chloride dropwise to the reaction system, and after the dropwise addition, heat up to the solvent After reacting at 100°C for 1 h, the solvent and unreacted thionyl chloride were removed by vacuum distillation to obtain 70.3 g of 3-acetoxybenzoyl chloride with a yield of 98% (crude product).

[0060] Step (3): Add 62.2 g of dimethyl malonate and 34.4 g of magnesium chloride to 600 ml of dichloromethane, slowly add triethylamine dropwise at an internal temperature of 5°C, and star...

technical field

[0001] The invention belongs to the field of chemical synthesis, and in particular relates to a synthesis method of 3-hydroxyacetophenone. Background technique

[0002] 3-Hydroxyacetophenone, also known as m-hydroxyacetophenone, m-hydroxyacetophenone, 3-hydroxyacetophenone, 3-acetylphenol, m-acetylphenol, 3-hydroxyacetylketone, etc., is the synthesis of phenylephrine Intermediates are in great demand in the market. The chemical structure of 3-hydroxyacetophenone is shown below:

[0003]

[0004] At present, the main synthetic methods of 3-hydroxyacetophenone include the following:

[0005] 1) The process route generally adopted by enterprises is to use acetophenone as the starting material, and to obtain m-nitroacetophenone through meta-nitration with mixed acid under the condition of -10~0°C, and crystallize and separate in ice water to obtain m-nitrobenzene Crude ethyl ketone, add the crude product to iron powder and hydrochloric acid system for reduc...

Examples

Embodiment 1

[0057]

[0058] Step (1): Add 50g of 3-hydroxybenzoic acid, 67g of acetic anhydride and 0.35g of concentrated sulfuric acid to the reaction vessel, heat up to 100°C under stirring and react for 30 minutes. After the reaction is over, distill under reduced pressure Removal of the solvent gave 64.5 g of 3-acetoxybenzoic acid (crude) as a white solid.

[0059] Step (2): Add 50 g of 3-acetoxybenzoic acid and 725 ml of toluene as a reaction solvent to the reaction vessel, then slowly add 56 g of thionyl chloride dropwise to the reaction system, and after the dropwise addition, heat up to the solvent After reacting at 100°C for 1 h, the solvent and unreacted thionyl chloride were removed by vacuum distillation to obtain 70.3 g of 3-acetoxybenzoyl chloride with a yield of 98% (crude product).

[0060] Step (3): Add 62.2 g of dimethyl malonate and 34.4 g of magnesium chloride to 600 ml of dichloromethane, slowly add triethylamine dropwise at an internal temperature of 5°C, and star...

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