Catalytic Synthesis of Ethyl Ester From Some Common Oils

Abstract

Catalytic conversion of ethanol to fatty acid ethyl esters (FAEE) was carried out by homogeneous and heterogeneous transesterification of melon seed, shea butter and neem seed oils using NaOH, KOH and 5wt%CaO/Al₂O₃ catalyst systems respectively.  Oil content of the seeds from n-hexane or hot water extract ranged from 25.0-33.3% and increased in the order melon seed< shea butter seed < neem seed. The heterogeneous catalyst maintained an optimal activity after 5 cycles of reusable applications and produced higher FAEE of 95.63% than 91.2% and 92.8% obtained with KOH and NaOH respectively. After purification by distillation of excess ethanol and neutralisation and separation of the homogeneous catalysts, the FAEE was subjected to qualitative analysis to determine its potential application as commercial biodiesel based on international specifications. With the exception of neem seed oil FAEE that shows high acid value and total ash content the esters could be used directly or as blend in diesel engines to give good performance.