Pustaka Ilmiah Universitas Padjadjaran

Abstrak

Synthesis Of Pulegol From Pulegyl Acetate

Synthesis of pulegol from pulegyl acetate has been carried out started from citronellal as precursor that achieved by vacuum distillation of citronella oil, and then refluxed it with anhydride of acetic acid catalyzed by Lewis acid followed by hydrolysis of the product in alcoholic KOH. Structure elucidation of the products was determined by GC-FID, GC-MS, FTIR, and 1H-NMR evidences. Isomers identification was determined by computational simulation. All experimental results were compared to the available literature. Cyclization of citronellal with anhydride of acetic acid catalyzed by Lewis acid FeCl3 yielded 60% mixture of (-)-isopulegyl acetate, (+)-neoisopulegyl acetate, (+)-isoisopulegyl acetate with ratio of 16:6:1 while 63% mixture of (-)-isopulegyl acetate, (+)-neoisopulegyl acetate, (+)-isoisopulegyl acetate with ratio of 122:43:1 was obtained over Lewis acid ZnCl2. Hydrolysis of pulegyl acetate (catalyzed by FeCl3) refluxed in KOH/alcohol gave 38% mixture of (-)-isopulegol, (+)-neoisopulegol, (+)-isoisopulegol with ratio of 62:17:2, and 59.5% with ratio of 15:2:3 due to pulegyl acetate (catalyzed by ZnCl2) hydrolysis products.