Method for preparing 4-methyl-4-trichloromethyl-2, 5-cyclohexadiene-1-ketone

Abstract

The invention discloses a method for preparing 4-methyl-4-trichloromethyl-2, 5-cyclohexadiene-1-ketone. The method comprises the following steps that p-cresol and carbon tetrachloride serve as a raw material, aluminum chloride serves as a catalyst, and hydrochloric ether serves as a solvent to have a reaction at the temperature of 33 DEG C to 45 DEG C; water is added into mixed liquor prepared in the S1 to carry out quenching reaction, and the quenching reaction time ranges from 15 min to 45 min; liquor separating is carried out, the liquor separating temperature ranges from 5 DEG C to 20 DEG C, the solvent is removed, and residue is obtained; alcoholic solutions and activated carbon are added into the obtained residue and stirred, the temperature ranges from 50 DEG C to 78 DEG C, the stirring time ranges from 0.5h to 1h, heat filtering is carried out, cooling is carried out until a solid body is not separated out, filtering and drying are carried out, and the 4-methyl-4-trichloromethyl-2, 5-cyclohexadiene-1-ketone is obtained. The preparation method is safe in technological operation, a purification technology is simple, the production period is short, industrialization production is facilitated, raw material cost is low, and the yield is stable.

Description

technical field [0001] The invention relates to the field of preparation of chemical intermediates, in particular to a preparation method of 4-methyl-4-trichloromethyl-2,5-cyclohexadien-1-one. Background technique [0002] 4-Methyl-4-trichloromethyl-2,5-cyclohexadien-1-one is an additive used in the electronics industry and has an important application prospect as a photoacid generator in electronic chemistry. [0003] The preparation method of 4-methyl-4-trichloromethyl-2,5-cyclohexadien-1-one is mainly prepared by Zincke-Suhl reaction at present, method one: Zincke and Suhl reported in 1906 that p-cresol and Aluminum trichloride is prepared by reacting in a carbon tetrachloride system. After the reaction is completed, the product is obtained by steam distillation, and the reaction yield is between 37-42%. [0004] The reaction formula of Method 1 is as follows: [0005] [0006] Subsequently, Melvin S.Newman and A.G.Pinkusd improved this method in 1954, the solvent wa...

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Problems solved by technology

[0008] For the reaction conditions of Method 1, carbon tetrachloride is used as both the reaction raw material and the reaction solvent. The amount of carbon tetrachloride is large and the reaction yield is low, which not only increases the reaction cost, but also is not environmentally safe. The product post-treatment process uses water vapor Distillation, the time to process the reaction is quite long, and the 20g-scale reaction requires five or six hours of steam distillation, and is accompanied by a strong pungent smell, so it is not conducive to industrial production

[0009] For the synthesis process of Method 2, although this route improves the product yield, it uses carbon disulfide with malodorous and low flash point as the reaction solvent, the process operation is dangerous, and the treatment process also uses steam distillation to obtain the product, so it is not conducive to Industrial production

[0010] In addition, a large amount of tar-like products will inevitably be produced in the above-mentioned methods, which increases the difficulty of handling, and it is difficult to repeat the yield to reach the optimal yield reported in the literature. In the latest literature report, the yield is between 12-30%, and the reaction is reproduced. poor sex

Steam distillation can be carried out in the laboratory, but when it is scaled up to an industrial scale of 100 kg, the continuous steam distillation time exceeds more than 100 hours, resulting in the cross-linking and polymerization of the product to generate a large amount of coke-like substances, resulting in a yield far lower than that of the laboratory Repeated results, unable to achieve industrial production

[0011] For the preparation method of 4-methyl-4-trichloromethyl-2,5-cyclohexadien-1-one in this field, there are low product yield, poor reaction reproducibility, high raw material cost, harsh production conditions, The production process is complicated, the cycle is long, and it is not conducive to industrial production

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