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A kind of technology and application of p-hydroxybenzaldehyde one-step oxidation esterification

A technology of p-hydroxybenzaldehyde and oxidative esterification, applied in the chemical industry, can solve the problems of weak active oxygen capacity, difficult product separation, poor product quality, etc., achieve high conversion rate, good product selectivity, and promote oxygen exchange Effect

Active Publication Date: 2022-03-04
SHANDONG UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Chinese patents CN 103193651 A, CN 103030565 A, CN 103193651 A, CN 104725235 A, CN104447308 A use p-hydroxybenzoic acid and methanol under the action of sulfuric acid catalyst and salt catalyst to convert acid into ester, but the product quality is poor, And there are toxic by-products, the problem of difficult product separation
The use of noble metals as catalyst active sites has the disadvantage of high cost, and the problem that the ability of active oxygen provided by the carrier is weak

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] (1) Conducted in a stainless steel jacketed off-pressure batch reactor, adding p-hydroxybenzaldehyde and methanol at a ratio of 1:10, and adding nano-cobalt-loaded Ce x Me 1-x o 2 solid solution catalyst with [bmim] + [BF 4 ] — The mass ratio of ionic liquid is 1:1. After sealing the reaction device, first feed oxygen to 0.3 MPa, the oxygen flow rate is 10mol / min, then start the circulating water bath heating temperature to 90°C, start stirring, and the reaction starts. After reacting for 2 h, stop air intake and stirring, turn off the heating, feed circulating cold water, cool down, and exhaust the gas.

[0020] (2) Pour the reaction liquid into a clean single-necked flask, distill off excess methanol by means of vacuum distillation, pour the remaining part into a beaker, add an appropriate amount of 2-10% sodium carbonate solution, cool and crystallize, and the obtained white solid can be Wash with deionized water and dry to obtain pure methyl p-hydroxybenzoate...

Embodiment 2

[0023] (1) Conducted in a stainless steel jacketed off-pressure batch reactor, adding p-hydroxybenzaldehyde and methanol at a ratio of 1:20, and adding nano-cobalt-loaded Ce x Me 1-x o 2 solid solution catalyst with [emim] + [BF 4 ] — The mass ratio of ionic liquid is 1:3. After sealing the reaction device, first feed oxygen to 0.3 MPa, the oxygen flow rate is 10mol / min, then start the circulating water bath to heat the temperature to 70°C, start stirring, and the reaction starts. After reacting for 2 h, stop air intake and stirring, turn off the heating, feed circulating cold water, cool down, and exhaust the gas.

[0024] (2) Pour the reaction solution into a clean single-necked flask, distill off excess methanol by vacuum distillation, pour the remaining part into a beaker, add an appropriate amount of 2-10% sodium carbonate solution, cool and crystallize, and obtain a white solid It can be washed with deionized water and dried to obtain pure methylparaben.

[0025]...

Embodiment 3

[0027] (1) Conducted in a stainless steel jacketed off-pressure batch reactor, adding p-hydroxybenzaldehyde and methanol at a ratio of 1:50, and adding nano-cobalt-loaded Ce x Me 1-x o 2 solid solution catalyst with [emim] + [PF 6 ] — The mass ratio of ionic liquid is 1:5. After sealing the reaction device, firstly feed oxygen to 0.6 MPa, the flow rate of oxygen is 10mol / min, then start the circulating water bath heating temperature to 80°C, start stirring, and the reaction starts. After reacting for 2 h, stop air intake and stirring, turn off the heating, feed circulating cold water, cool down, and exhaust the gas.

[0028] (2) Pour the reaction solution into a clean single-necked flask, distill off excess methanol by vacuum distillation, pour the remaining part into a beaker, add an appropriate amount of 2-10% sodium carbonate solution, cool and crystallize, and obtain a white solid It can be washed with deionized water and dried to obtain pure methylparaben.

[0029...

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PUM

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Abstract

The invention relates to a method for preparing methyl p-hydroxybenzoate through one-step oxidative esterification of p-hydroxybenzaldehyde. Add p-hydroxybenzaldehyde, methanol, nano cobalt catalyst and ionic liquid into a batch reaction kettle. Oxygen was introduced, heated and stirred in a circulating water bath. After reacting for 1 to 8 hours, stop the air intake and stirring, lower the temperature, exhaust the air, distill the excess methanol from the reaction solution through vacuum distillation, pour the remaining part into a beaker, and add an appropriate amount of 5% sodium carbonate solution , cooling and crystallization, the obtained white solid was washed with deionized water and dried to obtain pure methyl p-hydroxybenzoate, and the ionic liquid in the solution could be used repeatedly after purification. The method for one-step oxidative esterification of aldehydes to generate esters described in this patent is to generate unsaturated carboxylic acid esters by one-step oxidative esterification of unsaturated aldehydes and saturated alcohols through the co-catalysis of catalysts and ionic liquids. The method has simple operation steps and no Pollution, easy recycling of ionic liquids and catalysts, and high yields.

Description

technical field [0001] The invention relates to the technical field of chemical industry, in particular to a method for preparing methyl p-hydroxybenzoate through one-step oxidative esterification of p-hydroxybenzaldehyde. Background technique [0002] Paraben, also known as parabens, is a preservative with a large amount in the world, and has been widely used in food, beverage, cosmetics, medicine and other fields. The mechanism of action of parabens is basically similar to that of phenol. It can destroy the cell membrane of microorganisms, denature intracellular proteins, and inhibit the activity of respiratory enzymes and electron transfer enzymes of microorganisms. [0003] At present, there are many patents at home and abroad related to the preparation of methyl p-hydroxybenzoate. Some people use p-hydroxybenzoic acid and methanol as raw materials to prepare methyl p-hydroxybenzoate, and some also prepare methyl p-hydroxybenzoate by other methods. Chinese patents CN 10...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C67/39C07C69/84
CPCC07C67/39C07C69/84
Inventor 李玉超尹德峰田运郑艳霞王鸣傅忠君黄昊飞张天王静高文文黄福玲邓子实陈宁
Owner SHANDONG UNIV OF TECH