Method for synthesizing vanillin

Abstract

The invention relates to a method for synthesizing vanillin, comprising the following steps of: carrying out material thermal pretreatment by adopting a pressured reaction axe, and then pouring the materials into a cannular slurry reactor for vanillin synthetic oxidation reaction; and by using 4-methyl-2-metoxyphenol as a raw material, using ethylene glycol monomethyl ether or ethylene glycol monoethyl ether as a solvent and using oxygen as an oxidant, carrying out the oxidation reaction for synthesizing vanillin in a way of intermittently feeding oxygen. The conversion rate of the 4-methyl-2-metoxyphenol as the raw material reaches more than 99%, the selectivity of the vanillin reaches more than 93%, and the separation yield reaches about 82%. The oxidation test carried out in the cannular slurry reactor proves that the oxidation reaction of the 4-methyl-2-metoxyphenol can be successfully carried out in the reactor under a milder condition to synthesize vanillin, and the method avoids a danger of easy explosion of the traditional axe type oxidation technology process for synthesizing vanillin by using methanol as the reaction solvent and has the advantages of environmental-protection process and high efficiency.

Description

technical field [0001] The invention relates to the synthesis of vanillin, in particular to a safe process technology suitable for industrial production that uses 4-methyl-2-methoxyphenol as a raw material to synthesize vanillin through oxidation. Background technique [0002] The methods for synthesizing vanillin mainly include eugenol method, guaiacol method, sassafras oil method and lignin method. The raw materials used in these methods are difficult to obtain, the price is high, and the synthetic routes are complicated. Although the glyoxylic acid method has been successfully developed to produce vanillin, the synthesis process discharges a large amount of phenolic wastewater, which is likely to cause serious environmental pollution problems. The Chinese patent CN1167750A published on December 17, 1997 reported a process for the synthesis of vanillin by a one-step oxidation method successfully developed by the Dalian Institute of Chemical Physics, Chinese Academy of Sci...

AI Technical Summary

Problems solved by technology

The disadvantages of this process are: the reaction temperature is too high / long time leads to serious deep oxidation of the target product, and the product yield is low; the reaction pressure is not easy to control, and it is difficult to avoid the wide explosion limit of methanol-oxygen, so the risk of explosion is great

Because the tank-type oxidation process technology that also uses methanol as the reaction solvent cannot avoid the extremely wide explosion limit of methanol-oxygen, so this process also has serious explosion hazards

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