The ester product of the vegetable oil−alcohol
transesterification reaction (biodiesel) is the
best and the most popular diesel fuel alternative. The refining of
the transesterification reaction
products is technically difficult and brings an extra cost. Also,
the purity level of the biodiesel
must conform to European Union standards for alternative diesel fuels.
The target of this study
was to investigate the refining of the product mixture obtained by the
transesterification reaction
(with an alkali catalyst) of neutralized rapeseed oil (extracted from
the seeds of the rape plant
cultivated in the Thrace region of Turkey) with methanol. To
obtain pure biodiesel conformable
to the standards, methods of washing with hot distilled water,
dissolving in petroleum ether and
then washing with distilled water, and neutralization with
H2SO4 (1:1) were tested in the
refining
step. Washing with hot distilled water at 50 °C was chosen as
the best refining process. The
purity of the biodiesel obtained was about 99%.