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Preparation method of p-hydroxyacetophenone

A kind of p-hydroxyacetophenone, a certain amount of technology, applied in the field of preparation of p-hydroxyacetophenone, can solve the problems that o-hydroxyacetophenone cannot be completely eliminated, limited application, no difference, etc., achieves less impurities, simplified operation, The effect of reducing by-products

Inactive Publication Date: 2020-02-28
HUBEI ARTEC CARBOHYDRATE CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, major domestic manufacturers all adopt this route. The disadvantage is that the by-product o-hydroxyacetophenone of this process has many related documents. The yield of p-hydroxyacetophenone is between 30-60%, and the corresponding o-hydroxyacetophenone 60 -30% between
And due to the complex reaction, the reverse reaction will occur in the Fries rearrangement process to produce phenol, which will inevitably enter the by-product aluminum trichloride hexahydrate, which limits the application of the by-product aluminum trichloride hexahydrate as a water purifier
[0005] The second is a one-step method: using phenol and acetyl chloride as an anhydrous aluminum chloride catalyst to obtain p-hydroxyacetophenone and o-hydroxyacetophenone respectively. Compared with the two-step method, this method can limit the improvement of bit content, but there is no essential difference, and cannot completely eliminate the production of o-hydroxyacetophenone

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] Put 14.7g of anhydrous aluminum trichloride (0.11mol), 10.8g of anisole (0.1mol), and 50g of o-dichlorobenzene into a three-necked flask with stirring, cool down to 0-5°C in an ice-water bath, and drop 7.85 g acetyl chloride (0.1 mol), stirred for 2 hours. Then 5.65 g of ethanedithiol (0.06 mol) was added, and the temperature was raised to 30-35° C. for two hours. Pour the above reaction solution into 200g of ice water, bring the temperature of the solution down to 15-20°C, add hydrochloric acid to adjust the pH value to 1-2, put all the materials into a stirred flask, and the temperature at normal pressure is 95-100°C Carry out distillation under low temperature, distill o-dichlorobenzene and water azeotropically. After the distillation of o-dichlorobenzene is completed, stop the distillation, lower the temperature to 20°C, crystallize, filter with suction, and dry to obtain 12.9g of white crystalline solid. After testing , the p-hydroxyacetophenone content is 99.5%, ...

Embodiment 2

[0025] Put 800g of anhydrous aluminum trichloride (6mol), 540g of anisole (5mol), and 3000g of o-dichlorobenzene into a stirred 5L glass kettle, cool to 0-5°C in an ice-water bath, and dropwise add 400g of acetyl chloride ( 5.1mol), stirred for 3 hours. Then 272.6 g of ethanedithiol (2.9 mol) was added, and the temperature was raised to 30-35° C. and kept for 3 hours. Pour the above reaction solution into 10kg of ice water, lower the temperature of the solution to 20-25°C, add hydrochloric acid to adjust the pH value to 1-2, put all the materials into a stirred flask, and the normal pressure temperature is 95-100°C Carry out distillation under low temperature, distill o-dichlorobenzene and water azeotropically, after the distillation of o-dichlorobenzene is completed, stop the distillation, cool down to 20°C, crystallize, filter with suction, and dry to obtain 650g of white crystalline solid. After testing, The p-hydroxyacetophenone content is 99.5%, and the yield is 96%.

Embodiment 3

[0027] Put 698.3g of anhydrous aluminum trichloride (5.25mol), 540g of anisole (5mol), and 3000g of o-dichlorobenzene into a 5L glass kettle with stirring, cool down to 5-10°C in an ice-water bath, and add 412.1g of Acetyl chloride (5.25 mol), stirred for 3 hours. Then 272.6 g of ethanedithiol (2.9 mol) was added, and the temperature was raised to 35-40° C. for 2 hours. Pour the above reaction solution into 10kg of ice water, lower the temperature of the solution to 25-30°C, add hydrochloric acid to adjust the pH value to 1-2, put all the materials into a stirred flask, and the normal pressure temperature is 95-100°C Carry out distillation under low temperature, distill o-dichlorobenzene and water azeotropically. After the distillation of o-dichlorobenzene is completed, stop the distillation, lower the temperature to 20°C, crystallize, filter with suction, and dry to obtain 658g of white crystalline solid. After testing, The p-hydroxyacetophenone content is 99.6%, and the yie...

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Abstract

The invention relates to the technical field of chemical synthesis, in particular to a preparation method of p-hydroxyacetophenone. The preparation method comprises the following steps: 1, adding a certain amount of anisole, anhydrous aluminum trichloride and o-dichlorobenzene into a reactor, adding a certain amount of acetyl chloride after the temperature of the raw materials is reduced to 0-10 DEG C, and carrying out acetylation reaction at 0-10 DEG C for 1-3 hours; 2, adding a certain amount of a sulfide demethylation reagent into a system obtained in the step 1, and carrying out demethylation reaction for 1-3 hours at the temperature of 30-40 DEG C; 3, reducing the temperature of an obtained solution to 15-30 DEG C, and then adding hydrochloric acid to adjust the pH value of the solution to 1-2; and 4, distilling, crystallizing, centrifuging and drying to obtain p-hydroxyacetophenone. According to the method, anisole is used as a starting raw material, anhydrous aluminum trichloride and acetyl chloride are used as acetylation reagents, and ethanedithiol is used as a demethylation reagent, so that the generation of by-products is greatly reduced, the product yield is increased,the obtained product is high in purity and low in impurity content, the operation is simplified, and the production efficiency is greatly improved.

Description

technical field [0001] The invention relates to the technical field of chemical synthesis, in particular to a preparation method of p-hydroxyacetophenone. Background technique [0002] 4-Hydroxyacetophenone is widely used in medicine, cosmetics, and industry. It naturally exists in the stems and leaves of Artemisia spp. and soothing multifunctional cosmetic ingredient. In cosmetics, it can also be used as a substitute for traditional preservatives. It has antiseptic and synergistic effects, can promote the efficacy of various preservatives, and has excellent stability in high and low pH and temperature ranges. Can be used in a variety of formulations including sunscreens and shampoos. It has good compatibility with various cosmetic ingredients and packaging materials. [0003] There are two traditional preparation methods of p-hydroxyacetophenone: [0004] The first is a two-step method: first, phenyl acetate is produced by esterification of phenol and acetylating reagen...

Claims

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Application Information

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IPC IPC(8): C07C45/64C07C45/84C07C49/825C07C45/46C07C49/84
CPCC07C45/64C07C45/84C07C45/46
Inventor 李林飞
Owner HUBEI ARTEC CARBOHYDRATE CHEM
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