Preparation method of 2, 6-dihydroxytoluene in laboratory

Abstract

The invention discloses a preparation method of 2,6-dihydroxytoluene in a laboratory. The preparation method is characterized by comprising the following steps: 1, carrying out a sulfonation reaction; 2, carrying out an alkali fusion reaction; and 3, carrying out a decarboxylic reaction to obtain the 2, 6-dihydroxytoluene with the content of more than 92 percent. The preparation method disclosed by the invention has the advantages of being simple in production cost, easy and simple to operate and reliable in product quality.

Description

technical field [0001] The invention belongs to the field of chemical industry, in particular to a laboratory preparation method of 2,6-dihydroxytoluene. Background technique [0002] 2,6-dihydroxytoluene, also known as 2-methylresorcinol, is a white or off-white crystalline powder, easily soluble in water, the English name is: 2,6-dihyroxytoluene, the molecular formula is: C7H8O2, and the molecular weight is : 124, melting point: 118°C, boiling point: 264°C, structural formula: [0003] [0004] 2,6-Dihydroxytoluene is a very important fine chemical product, widely used in many fields such as medicine, pesticides, pigments, synthetic resins, photosensitive materials, hair dyes, etc., and because of its good disinfection and sterilization functions, in recent years It is also widely used in shampoos, skin care products and other products. And because the development and application of its downstream products are gradually increasing, the application field of this produc...

AI Technical Summary

Problems solved by technology

[0009] The disadvantage is: the main disadvantage of this synthetic route is that intermediates and products are difficult to purify, and the reaction process is not easy to control, resulting in high production costs and low overall yield

[0012] The disadvantage is: hydrogenation and dehydrogenation reactions will be carried out in the reaction process, both of which need to use a large amount of palladium carbon catalyst, and the reaction yield is low

[0015] Weaknesses are: this route uses 2,6-dinitrotoluene as starting raw material, obtains 2,6-diaminotoluene through high-pressure hydrogenation under palladium charcoal catalysis, then catalyzes with palladium charcoal under acid system, through high temperature (240°C) high-pressure hydrolysis to obtain 2,6-dihydroxytoluene product

[0019] Disadvantages: This method is a one-step reaction of resorcinol in ammonium chloride methanol system at 530°C under high temperature and high pressure to obtain the product

[0022] Disadvantages: This method is to introduce tert-butyl at the 4-position and 6-position of resorcinol first, then undergo an alkylation reaction under the action of methyl iodide, and then remove the tert-butyl group under the action of aluminum trichloride base get product

[0026] The disadvantages are: First, the raw material resorcinol is highly toxic and harmful to the human body, so the residual amount of resorcinol in the product must be very low

Second, the price of the raw material itself is relatively high, reaching 40,000 / ton

The third is that the reaction conditions are relatively harsh, and it is easy to introduce multiple carbon chains on the benzene ring, resulting in impure products and difficulties in subsequent product purification.

So far, this route is more in line with industrial production, but the price is still high, which limits the marketization of products

[0027] Some of the above synthesis methods are too expensive, some are not easy to operate, and some produce a large amount of waste acid and waste water, which are not conducive to industrial production

But as an important intermediate, 2-methylresorcinol has great application potential in many fields, especially in the fields of cosmetics and skin care products, and the price of 2-methylresorcinol is too high limit its application

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