2.3. Transesterification of palm oil
The activity of catalysts was evaluated in terms of fatty acid methyl
ester (FAME) conversion during transesterification of palmoil. The reaction was
performed in a 100mL flat-bottomed flask, equipped with a reflux
condenser and a magnetic stirrer. The reactor which was heated to
65 °C while stirring at 800 rpm was initially filled with 30 g of palm oil,
varied amounts of catalyst and different volumes of anhydrous methanol.
All of the experiments were performed at atmospheric pressure.
After the transesterification reaction, the catalyst was removed from
the mixture by centrifugation. The filtrate was kept in the funnel separator
for 24 h. The upper layer was subjected to rotary evaporation to remove
excess methanol and the product obtained was dried over sodium
sulfate before gas chromatography analysis.
The amount of FAME obtained through transesterification were analyzed
by gas chromatography (Agilent 7890A), equipped with a flame
ionization detector, a capillary column (DB-WAX, 30 m × 0.25 mm
i.d. × 0.25 μm), the programmed column oven, and a programmed
temperature injector. Methyl heptadecanoate was used as an internal
standard to quantify FAME content. The biodiesel yield was calculated
by the following expression: Yield = (weight of biodiesel × % FAME) /
(weight of oil). % FAME is the concentration of FAME obtained by GC
analysis.