Studies on the highly efficient catalyzation of sesamin to asarinin by phosphotungstic acid

Abstract

The conversion of sesamin to asarinin is a promising route for the production of asarinin. This work reports the affection of acid type and strength of the catalyst on the conversion of sesamin to asarinin and the effect of various reaction conditions in anhydrous ethanol using phosphotungstic acid (HPW) as catalyst. The experimental results indicate that the activity of sesamin conversion is determined by strong B acids. L acids are not active for the reaction, and do not show synergy with B acids for the formation of asarinin. Reaction time, HPW dosage and temperature have significant effects on sesamin conversion. A maximum asarinin yield of 57.93% was achieved. The reaction kinetics in the temperature range 55-75 °C were studied. The kinetic curves can be successfully fitted with an opposing first-order reaction model. The activation energy (Ea) for this reaction is found to be 105.2 ± 0.4 kJ/mol.

Keywords:
sesamin; asarinin; phosphotungstic acid; activation energy; acid catalysts