Biodiesel synthesis by simultaneous esterification and transesterification using oleophilic acid catalyst
Journal
Industrial and Engineering Chemistry Research
Journal Volume
49
Journal Issue
5
Pages
2118-2121
Date Issued
2010
Author(s)
Abstract
Solid-acid catalysts can perform transesterification and esterification simultaneously so that free fatty acids (FFAs) in oil can be converted into biodiesel to avoid the disposal of biomaterial. A carbon catalyst was prepared by pyrolyzing glucose at 400 �XC under a N2 stream. The catalyst was further sulfated using concentrated sulfuric acid. Transesterification of soybean oil and methanol was carried out at 150 �XC and 1.7 MPa in a pressurized autoclave. More than 90% biodiesel yield was achieved within 2 h with a molar ratio of methanol to soybean oil of 30:1. The total biodiesel yield for the mixture of soybean oil and palmitic acid decreased to 85% when 20 wt % palmitic acid was used. A rate equation based on the Langmuir?Hishelwood mechanism was established to describe the kinetic behavior of transesterification. The adsorption equilibrium constant of soybean oil was higher than those of the other species, implying an oleophilic surface of the sulfated carbon catalyst.
Type
journal article