Optimasi Sintesis Biodiesel dari Minyak Jarak Pagar (Jatropha curcas L.) melalui Proses Esterifikasi-Transesterifikasi

Abstract

Jarak pagar is such a quick growth plant. It is also very tolerant to climate and any type of soils. Oil from its seeds (curcas oil) has known as an energy resource. This research was done to establish the optimum condition on convertion of curcas oil into its fatty acid methyl esters (methyl esters), applicated as biodiesel which has appropriate commercial quality standard. Production of biodisel from high-acid curcas oil was done through estrans (esterification-transesterification) process, which is acid-catalyzed esterification process converting free fatty acid into methyl esters on the first step, than continued through base-catalyzed transesterification process converting triglyceride into methyl esters. According to factors affecting esterification process, optimation was done through varying factor of HCl catalyst (2 levels: 1,0 and 2,0%), reaction time (2 levels: 60 and 120 minutes), and methanol to oil ratio (5 levels: 0, 5, 10, 15, and 20% %). Optimation of transesterification process was done through varying factor of time (2 levels: 30 and 60 minutes) and methanol oil ratio (6 levels: 0, 5, 7½, 10, 15, and 20% %). Both processes were done at 60°C and NaOH was used as catalyst on transesterification process. Optimum condition of esterification process attained at 10% (%) of addition of methanol, 1% (%) of HCl catalyst, and 120 minutes reaction. Meanwhile, optimum condition of transesterification process attained at 10% (%) of addition of methanol and 30 minutes reaction. Then, methyl esters were produced through the optimum condition, and some of its parameters were analysed to establish the quality of biodiesel. Generally, biodiesel analysis covering cetane index, density, viscosity, acid value, ash contain, water and sediment contain, pour point, cloud point, flash point, and calor value, suggested that curcas oil biodiesel met the required standard. However, the resulted metil esters still had relatively high viscosity (5.863 cSt).