One mole of vegetable oil, six moles of methanol, and a
desired amount of catalyst were placed in a 300 ml stainless
steel reactor (Parr series reactor). The reactants were stirred at
350 rpm, which was sufficient to keep system uniform in temperature
and suspension. The reactor temperature was controlled by
a heater with a programmable PID temperature controller. The
system temperature was raised to 200 ◦C for the desired reaction
time, and then the reactor was cooled to room temperature. After
cooling, the catalyst was separated from the product mixture by
filtration. Phase separation of the filtrate resulted in the isolation
of the methyl esters and the glycerol. The glycerol phase (bottom
layer) was removed and kept in a separate container. Afterwards,
the methyl esters biodiesel phase (top layer) was washed
with 50 ◦C distilled water [9], and dried by adding sodium
sulfate (25% based on the weight of washed methyl esters
product)