Intensification of synthesis of fatty acid isopropyl ester using microwave

Abstract

Fatty acid isopropyl ester is one of the derivative products from vegetable oils such as crude palm oil (CPO). Chemically, fatty acid isopropyl esters can be synthesized from oils or vegetable fats with isopropanol using inorganic catalysts. The purpose of this research was to intensify the process of synthesis of fatty acid isopropyl esters from CPO using microwaves. Research variables used were CPO to isopropanol molar ratios of 1:3, 1:5, 1:7, 1:9, 1:11, and 1:13; reaction times of 1, 3, and 5 minutes; and KOH catalyst concentrations of 0.10, 0.15, 0.20, and 0.30 (%-w of CPO). The experimental result showed that the process variables affected the yield of fatty acid isopropyl esters. The highest yield obtained (80.5%) was found at molar ratio of CPO to isopropanol of 1:11, catalyst concentration of 0.2% (%-w of CPO), and reaction time of 5 minutes. With the same conditions, a 72.2% yield was obtained in 150 minutes using conventional transesterification. Fourier transform infrared analysis showed some specific functional groups in fatty acid isopropyl esters. In addition, viscosity, density, and acid number of fatty acid isopropyl esters produced conformed to the Indonesian National Standard (SNI) No. 7182-2015.