β-蒎烯合成对异丙基苯甲酸反应的研究

Study on Synthesis of p-Isopropylbenzoic Acid from βPinene

以松节油中β-蒎烯为原料,通过氧化、酸催化开四元环和脱氢三步反应,合成了对异丙基苯甲酸,总得率达到29.9%。并对各步反应条件进行了考察,重点讨论了脱氢步骤中各因素对反应的影响。用7.5%Pd/C催化二氢枯茗酸脱氢成对异丙基苯甲酸,对异丙基甲苯作溶剂,温和回流2 h,得率达到89%。

p-Isopropylbenzoic acid is synthesized from β-pinene, through a three-step sequence of oxidation, ring-opening and dehydrogenation. The overall yield is 29.9 %. The synthesis of the goal is a new approach. Besides, the conditions of each reac- tion step are studied. The dehydrogenation of dihydrocumic acid has been discussed emphatically. The optimum conditions of dehydrogenation are 7.5 % Pd/C as catalyst, p-isopropylmethylbenzene as solvent, refluxing time 2 h. The yield is 89 %.