3.1. Characterization of the crude roselle oil
The crude roselle oil used in this study was clear, viscous, and
yellow in color, without having undergone any further refining
for use as a biodiesel feedstock. Its properties were determined
to ascertain suitability for biodiesel production and to determine
a suitable production process for this feedstock. The predominant
fatty acids in the oil and its various important properties are shown
in Table 1
off and the methyl ester layer was purified by washing with hot
distilled water at 60C until the washing water had a pH value
similar to that of distilled water. The hot distilled water-to-crude
methyl ester ratio was 1:1. The washing step was done gently to
prevent the possibility of loss of methyl ester due to emulsion formation. Next, the methyl ester layer was dried under reduced pressure at 70C by rotary evaporator. Finally, the products from the
reactions were analyzed by using the standard test method, EN
14103, to determine methyl ester content.
(The averages of the results are shown inFigs. 1–3.) The optimum of each variable was
determinedbyconsidering the methyl ester content while the