Preparation method of 3-methyl-4-isopropyl-phenol

Abstract

The invention discloses a preparation method of 3-methyl-4-isopropyl-phenol, and belongs to the technical field of organic synthesis. The method includes the steps: (1) performing reaction of m-cresoland alkali under the condition of 5-20 DEG C in water to obtain an intermediate A; (2) performing reaction of the intermediate A and triphosgene in an organic solvent A at the temperature of 20-50 DEG C under alkaline conditions, cooling products after reaction, and separating organic phases to obtain an intermediate B; (3) performing reaction of the intermediate B, a catalyst B and isopropylation reagents in an organic solvent B under the condition of 5-15 DEG C, adding water after reaction, and separating organic phases to obtain an intermediate C; (4) hydrolyzing the intermediate C under the alkaline conditions at the temperature of 50-90 DEG C to obtain products. A synthetic process route is simple, raw materials are easily obtained, reaction time is short, post-treatment is convenient, purity is 97% or more, total yield is 70% or more, and the preparation method is simple in operation and suitable for industrial production.

Description

technical field [0001] The invention relates to the technical field of organic synthesis, in particular to a preparation method of 3-methyl-4-isopropylphenol. Background technique [0002] Cymene-5-ol, also known as 3-methyl-4-isopropylphenol, is a very safe, broad-spectrum and highly effective antifungal fungicide that can contact mucous membranes. The efficacy, and can inhibit product oxidation. It has the characteristics of safety, low toxicity, easy degradation, and little environmental pollution. It has been widely used by major cosmetics companies. Its scope of application is gradually expanding, and its usage is also increasing year by year. However, there has been no industrial production in China. How to prepare it simply High-purity substances are still a difficult problem encountered in the development and promotion of this product. [0003] The more common method for preparing 3-methyl-4-isopropylphenol is mainly to carry out isopropylation with m-cresol as raw...

AI Technical Summary

Problems solved by technology

For example, in DE2139622, the content of the product obtained by m-cresol and propylene under the catalysis of zinc catalyst is 19.5%, and in DE2528303, the reaction of m-cresol and propylene is catalyzed by aluminum salt, and the product obtained is only 2%, so it is difficult to obtain high-purity products. substance

[0004] In the "Fine Organic Chemical Raw Materials and Intermediates Handbook", m-cresol and chloroisopropane are catalyzed by aluminum trichloride in trichlorethylene, and m-cresol reacts with isopropanol in sulfuric acid. The selectivity is not high, and the product Separation is difficult, and the pollution in the production process is relatively large

[0005] US2603662 uses m-cresol as a raw material, first protects it with tert-butyl to obtain 6-tert-butyl-3-methylphenol, and then reacts with isopropyl chloride with carbon disulfide as a solvent under the catalysis of zirconium chloride to generate 6-tert-butyl-4-isopropyl-3-methylphenol, and then remove the tert-butyl group in a fixed bed at 265°C to obtain the target product. This process requires three steps of protection, isopropylation and deprotection , the reaction is complicated, and the deprotection needs special equipment fixed bed, and the temperature is high, the energy consumption is large, the conditions are relatively harsh, and it is not convenient for industrial implementation

[0006] CN103044205 uses m-toluidine as a raw material, undergoes isopropylation, and then diazotizes and hydrolyzes the amine group to obtain the target product. The diazotization process of this process is dangerous, which brings unstable factors to industrial production

[0007] Simultaneously, above-mentioned several methods all exist the problem that product purity is low and yield is low