Optimization of the Synthesis of Biolubricant from Palm Kernel Oil (PKO) with Alkali Produced from Oil-Palm Empty Fruit Bunches (OPEFB)

Abstract

In this study Design-Expert Software Version 11 was used to optimize the
synthesis of a biolubricant through the transesterification of palm kernel oil
(PKO) methyl ester and propane-1,2-diol, using potassium hydroxide (KOH)
produced from Oil-Palm Empty Fruit Bunches (OPEFB). The OPEFBs were
first pulverized into small bits, sun-dried, and burned. The resulting fine
particles were soaked in distilled water. The concentration of the filtrate was
determined by titration as 0.2 mol/dm3. The KOH produced was odourless,
slightly yellow, and hygroscopic. Response surface methodology (RSM) using
central composite design (CCD) was employed for the experiment design. The
effects of temperature, molar ratio, and reaction time on the yield of
biolubricant were evaluated. The predicted yield after process optimization
was found to agree with the experimental value. The optimum conditions
were obtained at a temperature of 100 °C, a molar ratio of 7:1, and a time of
200 min for a 96% biolubricant yield for PKO. Molar ratio and reaction time
were found to be the most significant variables for PKO. The Analysis of
Variance (ANOVA) implied that molar ratio and temperature were the most
significant factors affecting the yield of biolubricant.