Tin-Empty Palm Bunch Ash Impregnated Zeolite as Suitable Catalyst for Simultaneous Transesterification-Esterification Reaction of Palm Oil

A single-step method was developed for methyl ester production from palm oil using tin-empty palm bunch ash impregnated zeolite (Sn-PBA-Zeolite) as heterogeneous catalyst. The weight ratios between Sn solution and zeolite 1:4, while the weight of the PBA was varied from 5, 10, 15, 20, 25, and 30 g in 60 mL of distilled water. Effects of reaction time, molar ratio of reactants, and catalyst concentration on the yield of methyl ester were studied. Characteristics of methyl ester produced were also investigated. The optimal conditions for transesterification reaction carried out by using a Sn-PBA-Zeolite of 1:4:25 weight ratio were a palm oil/methanol molar ratio 1:6, catalyst concentration (3% wt/wt), and 3 hours reaction time, whereas the maximum yield of methyl ester reached 76.21% wt/wt. The optimal conditions for esterification reaction carried out by using a Sn-PBA-Zeolite of 1:4:5 weight ratio were a palm oil/methanol molar ratio 1:12, catalyst concentration (3% wt/wt), and 3 hours reaction time, and the maximum yield of methyl ester reached 94.76% wt/wt. The methyl ester resulted has a density of 0.89 g/mL, viscosity of 7.82 cSt, and dominated by a methyl oleate, methyl palmitate, and methyl stearate.