Recovering and recycling method of excessive methyl catechol in vanillin production process

A guaiacol and production process technology, which is applied in the field of recovery and recycling of excess guaiacol in the vanillin production process, can solve the problems of high energy consumption and complicated operation in rectification operation, and save steam , the effect of improving the purity and reducing the cost of recycling

Inactive Publication Date: 2013-09-25
SHANGHAI INST OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to solve the above-mentioned excessive guaiacol recovery process used in the production process of vanillin, the extraction solvent and guaiacol need to be separated by rectification, and guaiacol also needs to be p...

Method used

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Examples

Experimental program
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Effect test

Embodiment 1

[0027] A method for the recovery and recycling of excess guaiacol in the vanillin production process, specifically comprising the steps:

[0028] (1), at 12M 3 In the condensation reaction kettle of , add 8.0 M under cooling conditions 3 Water, adding 752 Kg of guaiacol (6.06Kmol) with a purity of 99.5%, and then adjusting the pH value of the solution with an aqueous sodium hydroxide solution with a concentration of 30% by weight to be 12.1 is the criterion to obtain a solution with a concentration of 9.1% by weight. guaiacol sodium salt solution;

[0029] Add 665 Kg of glyoxylic acid (4.49Kmol) with a concentration of 50% (weight percent) to the guaiacol sodium salt solution with a concentration of 9.1% by weight obtained above, and then use a hydrogen concentration of 30% by weight. The pH value of the sodium oxide aqueous solution was adjusted to 11.9, and the temperature was controlled to be 20 to 22° C. After the condensation reaction was carried out for 20 hours, it wa...

Embodiment 2

[0039] A method for the recovery and recycling of excess guaiacol in the vanillin production process, specifically comprising the steps:

[0040] (1), in the 2000ml condensation reaction kettle, add 1000ml water under cooling conditions, add 125.5 Kg of guaiacol (1.0mol) with a purity of 99.6%, and then adjust the solution with an aqueous sodium hydroxide solution with a weight percent concentration of 31% The pH value is 11.6, that is, the guaiacol sodium salt solution with a weight percent concentration of 12.6% is obtained;

[0041] In the above-obtained guaiacol sodium salt solution with a concentration of 12.6% by weight, add glyoxylic acid (0.7 mol) with a content of 103 grams and a concentration of 50% (by weight), and then use a hydrogen concentration of 31% by weight. The pH value of the sodium oxide aqueous solution was adjusted to 11.1, and the temperature was controlled to be 30 to 32° C. After the condensation reaction was carried out for 15 hours, it was detected...

Embodiment 3

[0052] A method for the recovery and recycling of excess ethyl guaiacol in the production process of ethyl vanillin, specifically comprising the steps:

[0053] (1), at 50 M 3 Add 28 M to the ethyl guaiacol preparation kettle 3 Water, the purity of 98.5% ethyl guaiacol (the main impurity is o-diphenyl ether, the content is 1.3%) 3465Kg (25.2kmol), the pH value is adjusted with the sodium hydroxide aqueous solution that the weight percent concentration is 30% under cooling Be as the criterion to 11.6, to obtain the ethyl guaiacol sodium salt solution with a weight percent concentration of 11.6%;

[0054] Add 2980kg 50% concentration (weight percent) glyoxylic acid (20.1 kmol) to the 11.6% weight percent concentration of ethyl guaiacol sodium salt solution obtained above, and then use 30 percent weight percent concentration of hydrogen The pH value of the sodium oxide aqueous solution is adjusted to 11.2, and the condensation reaction is carried out at a temperature of 12 to 1...

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Abstract

The invention discloses a recovering and recycling method of excessive methyl catechol in a vanillin production process. The method comprises the following steps of: carrying out condensation reaction on the methyl catechol and glyoxylic acid under an alkaline condition after the methyl catechol is prepared into a methyl catechol sodium phenolate solution in the vanillin production process; adjusting the pH to 3-5 after the condensation reaction is finished; then extracting and separating by using a non-polar organic solvent to obtain methyl catechol extract liquor; carrying out reverse extraction on the obtained methyl catechol extract liquor by using proper concentration of an aqueous solution of sodium hydroxide, so that the methyl catechol in the methyl catechol extract liquor is transformed into methyl catechol sodium phenolate and transferred into a water phase, so as to obtain a water solution of the methyl catechol sodium phenolate; and adding the methyl catechol to the obtained water solution of the methyl catechol sodium phenolate to prepare the methyl catechol sodium phenolate solution with the concentration which is required for carrying out condensation reaction with the glyoxylic acid, so as to achieve recycling. By adopting the method, separation and purification of the methyl catechol can be simultaneously achieved; and the method is simple to operate, less in steam consumption, and energy-saving. Therefore, the production cost of the vanillin is reduced.

Description

technical field [0001] The invention relates to a method for recovering and recycling excess guaiacol in the production process of vanillin. Background technique [0002] Vanillin is an important food additive and spice product, which can be divided into vanillin (3-methoxy-4-hydroxybenzaldehyde) and ethyl vanillin (3-ethoxy-4- hydroxybenzaldehyde). At present, vanillin is mainly synthesized by three steps of condensation, oxidation and decarboxylation of guaiacol and glyoxylic acid as raw materials. When guaiacol and glyoxylic acid are condensed, there are three selectivities for simultaneous condensation of ortho, para and ortho-para. In order to improve the single condensation selectivity of guaiacol and glyoxylic acid, reduce the At the same time, due to the selectivity of condensation, guaiacol will generally be in excess of 10-50% during the reaction. These excess guaiacol raw materials need to be recovered after the condensation reaction is completed. [0003] The...

Claims

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Application Information

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IPC IPC(8): C07C43/23C07C41/38C07C59/64C07C51/367
Inventor 毛海舫潘仙华王朝阳吴建新王立志
Owner SHANGHAI INST OF TECH
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