Preparation method for p-hydroxybenzoic acid

A technology of p-hydroxybenzoic acid and trifluoromethylaniline, which is applied in the field of preparation of p-hydroxybenzoic acid, can solve the problems of low yield, high cost, long reaction time, etc., and achieves simple post-treatment, short synthesis route and fast reaction time. short time effect

Inactive Publication Date: 2016-04-13
HUBEI UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] There are many ways to produce p-hydroxybenzoic acid, chemical methods such as potassium phenate carboxylation, or potassium salicylate heating, or diazotization and Sandmeyer reaction from p-aminophenol. The process must be carried out under high temperature and high pressure, which requires a large amount of energy consumption, resulting in high production efficiency and low cost, especially the generation of environmental pollutant phenol in the synthesis route, which brings great difficulties to the treatment of industrial wastewater
The biosynthesis method uses plants or bacteria to synthesize, the reaction time is long, and the yield is low

Method used

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  • Preparation method for p-hydroxybenzoic acid
  • Preparation method for p-hydroxybenzoic acid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] Add 100mL dimethyl sulfoxide into a 500mL two-necked flask, add 20.5g pyrazole, 16g p-trifluoromethylaniline, and 17g potassium hydroxide in sequence, stir and dissolve, heat to reflux for 1 hour, and cool to room temperature. Add 200mL of water to dissolve, add dichloromethane and extract three times, 200mL each time. The organic phase was dried with anhydrous magnesium sulfate and separated by column chromatography to obtain 24.3 g of 4-tripyrazolylmethylaniline as a light yellow solid with a yield of 80.4%.

[0018] Add 18.3g of 4-tripyrazolylmethylaniline and 60mL of water into a three-necked flask equipped with a reflux condenser, slowly add 15mL of concentrated sulfuric acid and stir within 15 minutes, and add 23.3% 19.6 g of sodium nitrite aqueous solution was stirred for 15 minutes, and 16.5 mL of 15.5% sulfuric acid solution was added dropwise within 15 minutes. The temperature was raised to 50°C for 1 h, cooled naturally, and ethyl acetate was added for separ...

Embodiment 2

[0020] Add 20mL of dimethyl sulfoxide into a 100mL two-necked flask, add 4.1g of pyrazole, 3.2g of p-trifluoromethylaniline and 3.4g of potassium hydroxide in sequence, stir and dissolve, heat to reflux for 1h, and cool to room temperature. Add 40mL of water to dissolve, add dichloromethane and extract three times, 40mL each time. The organic phase was dried with anhydrous magnesium sulfate and separated by column chromatography to obtain 4.98 g of light yellow solid 4-tripyrazolylmethylaniline with a yield of 81.5%.

[0021] Add 3.05g of 4-tripyrazolylmethylaniline and 10mL of water into a three-necked flask equipped with a reflux condenser, slowly add 2.5mL of concentrated sulfuric acid dropwise within 5 minutes and stir, then add 23.3% sulfuric acid in an ice bath for 5 minutes. Sodium nitrate aqueous solution 1.3g, stirred for 15min. 1.1 mL of 15.5% sulfuric acid solution was added dropwise over 5 minutes. Raise the temperature to 100°C for 15 minutes, cool naturally, ad...

Embodiment 3

[0023] Add 10 mL of dimethyl sulfoxide to a 50 mL two-necked flask, add 2.05 g of pyrazole, 1.6 g of p-trifluoromethylaniline, and 1.7 g of potassium hydroxide in sequence, stir and dissolve, heat to reflux for 1 h, and cool to room temperature. Add 20mL of water to dissolve, add dichloromethane and extract three times, 20mL each time. The organic phase was dried with anhydrous magnesium sulfate, and separated by column chromatography to obtain 2.35 g of light yellow solid 4-tripyrazolylmethylaniline with a yield of 77.7%.

[0024] Add 1g of 4-tripyrazolylmethylaniline and 4mL of water into a three-necked flask equipped with a reflux condenser, slowly add 2mL of concentrated sulfuric acid dropwise within 5 minutes and stir, then slowly add 23.3% sulfuric acid in an ice bath for 5 minutes. 0.5 g of sodium nitrate aqueous solution was stirred for 15 min, and 0.4 mL of 15.5% sulfuric acid solution was added dropwise within 5 min. Raise the temperature to 30°C for 2 hours, cool n...

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Abstract

The invention relates to a preparation method for p-hydroxybenzoic acid. The preparation method comprises successively adding pyrazole, 4-aminobenzotrifluoride and potassium hydroxide into dimethyl sulphoxide, dissolving, heating and refluxing for 1 h, cooling, adding water into the refluxing liquid for dissolving, adding dichloromethane, separating the liquid, extracting for three times, drying the organic phase with anhydrous magnesium sulfate, and performing column chromatography separation for obtaining 4-(tri(pyrazol-1-yl)methyl)aniline; and dropwise adding concentrated sulfuric acid into a mixed solution of 4-(tri(pyrazol-1-yl)methyl)aniline and water, dropwise adding a sodium nitrite aqueous solution under an ice bath condition with stirring, dropwise adding a sulfuric acid solution with the concentration of 15.5%, heating to 30-100 DEG C, reacting for 15 min to 2 h, naturally cooling, adding ethyl acetate and performing liquid-separation extraction for three times, performing reduced-pressure rotary evaporation, drying the organic phase with anhydrous sodium sulfate, and performing vacuum drying, so as to obtain p-hydroxybenzoic acid. The reaction synthetic route is short, reaction time is short, yield is high, and postprocessing is simple. The yield of 4-(tri(pyrazol-1-yl)methyl)aniline is about 80%, and the yield of p-hydroxybenzoic acid is about 99%.

Description

technical field [0001] The invention belongs to the field of chemical synthesis, and in particular relates to a preparation method of p-hydroxybenzoic acid. Background technique [0002] p-Hydroxybenzoic acid is a very versatile raw material for organic synthesis. It is used as an intermediate for the preparation of dyes and pesticides. . Ester derivatives of p-hydroxybenzoic acid such as methyl, ethyl, propyl, butyl, isopropyl, and isobutyl p-hydroxybenzoate are widely used as food additives in soy sauce, vinegar, and refreshing drinks (except soft drinks) ), fruit flavorings, fruits and vegetables, pickled products, etc. It can also be used as preservatives, fungicides, and insecticides. [0003] There are many ways to produce p-hydroxybenzoic acid, chemical methods such as potassium phenate carboxylation, or potassium salicylate heating, or diazotization and Sandmeyer reaction from p-aminophenol. The process must be carried out under high temperature and high pressure,...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C51/00C07C51/42C07C65/03C07D231/12
CPCC07C51/00C07C51/42C07D231/12C07C65/03
Inventor 王薇任家强周宝晗孙丹李陵岚
Owner HUBEI UNIV OF TECH
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