STM Article Repository

Comparative study of acid-base catalysed (ABC) and base catalysed (BC) processes for biodiesel production using high FFA shea butter was undertaken. The effect of methanol to oil ratio, catalyst loading and temperature on percentage yield of shea biodiesel from ABC and BC processes were studied. The ABC and BC samples obtained were characterised for physico-chemical properties using ASTM standard methods and fatty acid profile using GC-MS. The results show that methanol to oil ratio of 10:1 (%, w/w) gave highest yields of 84.67 and 67.21%, catalyst loading of 1.0 (%, w/w) gave 86.46 and 80.01% while temperature of 40 °C gave 86.48 and 67.23% for ABC and BC, respectively. The physico-chemical properties obtained in this study for ABC and BC are relatively close and within the range of ASTM standard. GC-MS analyses show that BC comprises 50.26% unsaturated and 49.75% saturated while ABC comprises 12.08% unsaturated and 87.91% saturated of FAMEs. The products from the two processes did not contain linolenic acids and polyunsaturated fatty acid. However, the physical and chemical properties of the samples indicate better quality in ABC than BC but the reaction time, energy cost and corrosive nature favoured BC than ABC.