Biodiesel Synthesis from Palm Fatty Acid Distillate Using Tungstophosphoric Acid Supported on Cesium-Containing Niobia

Tungstophosphoric acid supported on cesium-containing niobia (TPA/Cs (x) /Nb2O5, x = 1.0-2.5) catalysts were prepared by a two-step impregnation method, and their physico-chemical properties were investigated. The initial studies on the esterification of oleic acid with methanol revealed that TPA/Cs ratio affected the acidity as well as the activity of the catalysts. Among the catalysts tested, TPA/Cs-1.0/Nb2O5 exhibited the best performance. In addition, the efficiency of TPA/Cs-1.0/Nb2O5 for biodiesel synthesis from palm fatty acid distillate (PFAD), a by-product from palm oil industry, was demonstrated, and the reaction parameters were also evaluated. Over 90% yield of FAME was achieved, and the properties of the biodiesel obtained from PFAD met the standard requirements for biodiesel fuel. However, deactivation of the catalysts was observed, possibly due to structural transformation or organic residues blocking the active sites.