Transesterification was carried out in a screw-capped vial
(capacity ca. 50 cm3
) with a Teflon/silicon rubber septum that retained
any vaporized mixture. The reaction vial was immersed in
a thermostatic water bath to maintain the reaction temperature
between 65 and 70 C, slightly below the boiling point of methanol
(Gryglewicz et al., 2003). The bath was placed on the plate of a
magnetic stirrer. During the reaction, the mixture of oil, catalyst
and methanol was completely stirred by a cross-headed stirrer bar.