Different biodiesel runs carried out by varying these parameters
are listed in Table 2. Fig. 4 shows the effect of catalyst concentration
on the yield of FAME. The reaction was carried out at 65 C
using 12:1 methanol to oil ratio for 2 h. It was seen that FAME yield
increased with increase in the amount of catalyst. However, higher
amount of catalyst loading caused more mass transfer resistance
due to the highly viscous mixture [12]. Fig. 5 shows the variation
of yield of FAME with methanol to oil ratio. The reactions were carried
out at 65 C using 4 wt% catalyst for 2 h. It was observed that
the yield increased with increase in the molar ratio of methanol to
oil initially, but after a certain point, it decreased. This could be due
to the shift in equilibrium to the backward direction in presence of
excess methanol. This happens due to the dissolution of glycerol in
excess methanol and thereby interfering with the reaction of
methanol with the reactants [12,23]. Fig. 6 depicts the variation
in the yield of FAME with reaction time. The reaction was carried
out at 65 C using 12:1 methanol to oil ratio and 4 wt% catalyst.
At lower reaction time, the yield was very less. The reaction mixture
needed some amount of time for proper dispersion. Later yield
increased with increase in time and attained a maximum value. All
the graphs are shown with a maximum deviation of 2%.