The correlation between the effects of base strength and basicity
of the catalyst on the catalytic activity was studied. Fig. 5 shows the
catalytic trend of CaOeLa2O3 series with its basicity. The results
illustrated the catalytic trends were parallel to the variability of
total basicity. This study was in good agreement with previous
studies by Olutoye and Hameed (2009) [39], stating that the higher
basicity shall enhance the catalytic activity.
Other than basic active site of catalyst, it is anticipated that
catalytic activity of CaOeLa2O3 can be contributed by the acidity of
CaOeLa2O3 catalyst. Hence, an esterification reaction between oleic
acid with methanol was carried out by using CL8.0 catalyst. This
study was used to examine the capability of optimized CL8.0 to act
as acid catalyst and esterifies FFA in jatropha oil to methyl ester. In
this experiment, oleic acid (as a model compound of FFA) with
9 wt.% (similar to FFA content in jatropha oil) was reacted with
methanol at same transesterification condition (160 C, 3 h, 3 wt.%
of catalyst and methanol/oil molar ratio of 25). Oleic acid was
successfully converted to methyl oleate with around 95%, which
means that CL8.0 catalyst consisted acid sites for esterification
reaction.