Method for in situ preparing o-vanillin by taking pyrocatechol as raw material

Abstract

A method for in situ preparing o-vanillin by taking pyrocatechol as the raw material and relates to production methods of drug materials. The method comprises, firstly, taking the pyrocatechol with apurity degree of 99 w% as the raw material; secondly, taking absolute ethyl alcohol as solvent and polyethylene glycol and sodium hydroxide as catalysts; thirdly, taking acetonitrile as solvent, triethylamine as acid-binding agent and magnesium chloride as catalysts; fourthly, adding sodium chloride into reaction liquid, performing chromatographic layering, and removing a water layer; fifthly, cooling raffinate down to -10 DEG C for freezing concentration, and performing rotary evaporation and separation to obtain oily 2-hydroxy-3-methoxybenaldehyde. The raw material applied is a bulk organicraw material of the pyrocatechol, which is easy to acquire and low in price; by means of the technical processes of methylation and then formylation, the method for in situ preparing the o-vanillin bytaking the pyrocatechol as the raw material can shorten the technical process and reduce the cost, thereby being applicable to industrial production of the o-vanillin, overcoming the limitation of yield of the o-vanillin and achieving significant economic and social benefits.

Description

technical field [0001] The invention relates to a preparation method of a drug raw material, in particular to a method for preparing o-vanillin by using catechol as a raw material. Background technique [0002] Ortho-vanillin is an important intermediate in medicine and organic synthesis. 2,3-dimethoxytoluene, 1,2,3-trimethoxybenzene, brominated ortho piperonal, novolac epoxy resin and 2,3-dimethoxy O-vanillin is an important raw material for the production of berberine. [0003] At present, there is no report on the industrial production of ortho-vanillin. It is only obtained as a by-product of vanillin production after purification and separation. The annual output of vanillin in my country is about 10,000 tons, distributed in 14 enterprises, with a kiloton level There are only two companies, and there are two companies with hundreds of tons of ortho vanillin, and the product quality is not guaranteed, there are many impurities, and subject to the difficulty of separating...

AI Technical Summary

Problems solved by technology

[0003] At present, there is no report on the industrial production of ortho-vanillin. It is only obtained as a by-product of vanillin production after purification and separation. The annual output of vanillin in my country is about 10,000 tons, distributed in 14 enterprises, with a kiloton level There are only two companies, and there are two companies with hundreds of tons of ortho vanillin, and the product quality is not guaranteed, there are many impurities, and subject to the difficulty of separating isomer mixtures, the so-called analytically pure ortho vanillin in the market Berberine also contains isomer impurities, which seriously restricts the large-scale production of berberine drugs in both yield and quality, which is a strategic issue

[0004] Taking guaiacol as raw material through formylation reaction, due to the low selectivity, only the mixture of vanillin and ortho-vanillin can be obtained; Removal of sulfonic acid, continue electrolytic oxidation, deshrinkage and extraction to prepare ortho-vanillin, which has not been industrialized due to the limitation of electrolytic oxidation process; from 5-formyl vanillin, dealdehyde group under catalytic conditions, combined with The preparation of ortho-vanillin by falling film distillation is also limited to experimental research

Images