In summary, CaO(OE) catalysts were prepared and adopted for
the catalytic transesterification of palm oil. In the magnetically
stirred system, CaO(OE) catalysts showed comparable catalytic
activity to the CaO(Lab). With ultrasonic assistance, significant
increase in the biodiesel yield was observed. The maximum yield
(92.7%) was obtained under the following conditions: catalyst
8 wt.%, methanol-to-oil ratio 9:1, reaction time 60 min and ultrasonic power 60% amplitude. Besides, this unique catalyst could
be reused for more than 8 times without significant loss of activity,
indicating a desirable recyclability. Thus, the CaO(OE) catalysts
could be a promising catalyst for biodiesel production