Potential of palm fatty acid distillate as a feedstock in the synthesis of ethyl esters using solid SO4 2-/TiO2-SiO2 catalysts

Utilization of by-products from the cooking oil industry, such as palm oil fatty acid distillates (PFAD) can reduce the cost of producing ethyl ester/biodiesel. This PFAD is processed into biodiesel using SO4 2 −/TiO2-SiO2 solid catalyst and ethanol reagent. The central composite design in Response Surface Methodology is applied in optimizing the effect of process variables such as the amount of catalyst, ethanol to PFAD molar ratio and reaction time. The results of the study show that the best-operating conditions with 98.89% ethyl ester conversion were achieved with the catalyst amount of 5% w, a molar ratio of 13 in reaction time of 2.25 hours. The presence of SO4 2 −/TiO2-SiO2 catalyst components can be characterized using SEM-EDX. A functional group showing the presence of ethyl ester in biodiesel products has been identified using FTIR. Ethyl ester properties related to biodiesel properties can be shown as saponification value: 583.8446 mg/g, iodine value: 8.8714 mg/g and cetane value: 49-54.