Processing method of nipagin ester

A technology of parabens and processing methods, which is applied in chemical instruments and methods, preparation of carboxylic acid esters, preparation of organic compounds, etc., can solve the problems of low yield of calcium oxide dehydration method and high cost of preparation process, and avoid equipment Corrosion is serious, the effect of reducing the dosage and increasing the yield

Pending Publication Date: 2022-03-08
ZHEJIANG SHENGXIAO CHEM
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The catalyst preparation process of the solid heteropolyacid catalysis method is relatively expensive; although the microwave irradiation catalysis method can shorten the reaction time, it needs special experimental equipment; the calcium oxide dehydration method also has the disadvantage of low yield, etc., which needs to be improved

Method used

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  • Processing method of nipagin ester

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Experimental program
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Effect test

Embodiment 1

[0019] Embodiment 1: for the processing method of a kind of parabens disclosed by the present invention, comprising,

[0020]

[0021] The salt-forming dehydration process of potassium phenate obtained from the reaction of phenol and potassium hydroxide; the carboxylation process of dipotassium p-hydroxybenzoate obtained from the reaction of potassium phenate and carbon dioxide; the reaction of dipotassium p-hydroxybenzoate and sulfuric acid to obtain p-hydroxyl The acid precipitation process of benzoic acid and potassium sulfate; the recovery process of water-absorbing agent prepared from potassium sulfate and activated carbon; and the esterification process of paraben ester prepared from p-hydroxybenzoic acid, alcohol compounds, sulfuric acid and water-absorbing agent.

[0022] Wherein, the alcohol compound is methanol, ethanol, propanol, butanol or isobutanol.

Embodiment 2

[0023] Embodiment 2: be the processing method of a kind of parabens disclosed by the present invention, the difference with embodiment 1 is,

[0024] S1 is the salt-forming dehydration process of potassium phenate obtained by the reaction of phenol and potassium hydroxide

[0025] First put potassium hydroxide and phenol into the carboxylation reaction kettle, raise the temperature to 100±5°C under normal pressure, keep stirring for more than 30 minutes, until the content of free alkali in the reaction solution is 0.8%; then raise the temperature to 140±5°C under normal pressure, Then reduce the reaction pressure to 10.6kPa, evaporate and dehydrate for 48 minutes; then raise the temperature to 200±10°C, and increase the reaction pressure to 2.76kPa synchronously, and the dehydration is completed, and a potassium phenate solution containing potassium phenate is obtained;

[0026] S2 The carboxylation process of dipotassium p-hydroxybenzoate obtained from the reaction of potassi...

Embodiment 3

[0036] Embodiment 3: be the processing method of a kind of parabens disclosed by the present invention, the difference with embodiment 1 is,

[0037] S1 is the salt-forming dehydration process of potassium phenate obtained by the reaction of phenol and potassium hydroxide

[0038] First put potassium hydroxide and phenol into the carboxylation reaction kettle, raise the temperature to 100±5°C under normal pressure, keep stirring for more than 30 minutes, until the content of free alkali in the reaction solution is 0.3%; then raise the temperature to 140±5°C under normal pressure, Then reduce the reaction pressure to 11.0kPa, evaporate and dehydrate for 30min; then raise the temperature to 200±10°C, and increase the reaction pressure to 2.50Pa synchronously, and the dehydration is completed, and the potassium phenate solution containing potassium phenate is obtained;

[0039] S2 The carboxylation process of dipotassium p-hydroxybenzoate obtained from the reaction of potassium p...

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Abstract

The invention relates to a processing method of nipagin ester, which comprises the following steps: reacting phenol with potassium hydroxide to obtain potassium phenolate; a carboxylation process in which potassium phenolate reacts with carbon dioxide to obtain dipotassium p-hydroxybenzoate; an acidification process of reacting the dipotassium p-hydroxybenzoate with sulfuric acid to obtain p-hydroxybenzoic acid and potassium sulfate; a recovery process of a water absorbent prepared from potassium sulfate and activated carbon; and an esterification process of preparing nipagin ester from p-hydroxybenzoic acid, an alcohol compound, sulfuric acid and a water absorbent. According to the method, potassium sulfate produced in the processing process is recycled and prepared into the water absorbent, so that the consumption of sulfuric acid can be reduced, serious corrosion to equipment due to high concentration of the sulfuric acid in a reaction system is avoided, the potassium sulfate and the sulfuric acid can act synergistically, the esterification reaction is accelerated, and the yield of the nipagin ester is improved.

Description

technical field [0001] The invention relates to the technical field of organic synthesis, in particular to a processing method of parabens. Background technique [0002] Paraben is an internationally recognized broad-spectrum high-efficiency food preservative. The United States, Europe, Japan, Canada, South Korea, Russia and other countries allow paraben to be used in food, and is widely used in soy sauce, vinegar and other condiments , pickled products, baked food, sauce products, beverages, rice wine and fruit and vegetable preservation and other fields. China GB2760 stipulates that ethylparaben, propylparaben and sodium methylparaben, sodium ethylparaben and sodium propylparaben can be used as food preservatives. [0003] At present, the commonly used production method of parabens is to synthesize p-hydroxybenzoic acid first, and then use sulfuric acid as a catalyst to obtain it by reflux esterification with p-hydroxybenzoic acid and alcohol compounds at a certain temper...

Claims

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Application Information

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Patent Type & AuthorityApplications(China)
IPC IPC(8): C07C67/08C07C69/84
CPCC07C67/08C07C69/84
Inventor袁鹏章丽冯永胜秦秀芳胡秀雪王先英郭小忠
OwnerZHEJIANG SHENGXIAO CHEM