3-乙酰基-4-羟基苯甲酸的无溶剂合成及正交设计工艺优化

Solvent-free synthesis of 3-acetyl-4-hydroxybenzoic acid and process optimization via orthogonal test

以4-乙酰氧基苯甲酸甲酯为原料,经无溶剂的Fries重排法合成得到3-乙酰基-4-羟基苯甲酸.采用L_(9)(3^(4))正交实验,考察了物料投料比、反应温度和反应时间等参数对目标产物收率的影响,并对重排反应机理进行了探讨.结果表明,4-乙酰氧基苯甲酸甲酯与无水三氯化铝的用量比为1∶3,反应温度为170℃,反应时间为2 h,反应收率达95%.通过^(1)HNMR和IR对产物的结构进行了表征.该工艺原料廉价易得、操作简单、环境友好、收率高,适合工业化生产.

3-Acetyl-4-hydroxybenzoic acid was synthesized by solvent-free Fries rearrangement method with methyl 4-acetoxybenzoate as a raw material.The mechanism of rearrangement reaction was discussed.The effect of feeding ratio,reaction temperature and reaction time on the yield of target product was investigated by L_(9)(3^(4))orthogonal experiment.The results showed that the optimal synthetic conditions were as follows:the ratio of methyl 4-acetoxybenzoate to anhydrous aluminum trichloride was 1:3,under the reaction temperature of 170℃and the reaction time of 2 h with the yield of 95%.The structure of the title product was characterized by^(1)H NMR and IR.The raw material for this synthetic route is cheap and easy to obtain.The synthetic process is simple to operate with the advantage of environmental friendliness and high yield,which is suitable for industrial production.