Preparation method of 2,6-dihydroxytoluene

Abstract

The invention discloses a preparation method of 2,6-dihydroxytoluene. The preparation method comprises the following steps of: by taking the 2,6-dihydroxytoluene as an initial raw material; and under the effects of a composite tube solid acid catalyst, preparing the 2,6-dihydroxytoluene through high-temperature steam hydrolysis, wherein the liquefied 2,6-dihydroxytoluene and deionized water are fed into a fixed bed reactor according to a flow ratio of (1:1.5)-(1:10), and the mixed materials are subjected to a hydrolysis reaction through the effect of the solid acid catalyst filled in the fixed bed reactor at high temperature. By utilizing the preparation method, liquid acid with large environment pollution is avoided, at the same time, high-temperature equipment and acid corrosion resisting materials are not used, so that the acid corrosion problem of the equipment in the conventional method is overcome, the environment pollution is reduced, and the economic cost is lowered; moreover the process is simple, the product purity and the yield achieve a good level, the purity of the prepared 2,6-dihydroxytoluene is more than 99% under the optimal condition, and the yield can be 95%.

Description

technical field [0001] The invention relates to the field of fine organic synthesis, in particular to a preparation method of 2,6-dihydroxytoluene. Background technique [0002] 2,6-Dihydroxytoluene can be used in dyestuffs, medicine, pesticides and many other fields, especially as an important component of hair dyes, and is widely used. The currently reported synthesis methods of 2,6-dihydroxytoluene mainly include the following 5 methods, which are specifically discussed in relevant literature (Wu Yonghong et al., Research Progress in the Synthesis of 2-Methyl Resorcinol. Chemical Engineering and Equipment. 2008 .Second Issue; Chen Qiang et al., Preparation of 2-Methyl Resorcinol. Modern Pesticides. Vol.40No.4; Sun Hongtao et al. Preparation of 2-methylresorcinol. Dyes and dyeing Vol.41No.5; 2 Liu Xuelin et al. Synthesis of 2,6-dihydroxytoluene. Applied Chemistry. Vol.21No. 10). [0003] (1) Taking p-toluic acid as starting material: [0004] [0005] This route nee...

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Problems solved by technology

The study found that method (5) is the most promising path from the perspective of the simplicity of the process and economic cost. Nanjing University of Science and Technology also made considerable research on the second step of the path (Du Binbin 2010), generally speaking, acid hydrolysis is still carried out under high temperature and high pressure. Such a reaction system has very high requirements for the material of industrial equipment, and the service life is short and the investment is large.

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