Alkaline Conventional and in Situ Transesterification of Cottonseed Oil for the Production of Biodiesel

In the present work, the transesterification of cottonseed oil with methanol and ethanol, in the presence of alkali catalyst (NaOH), using low-frequency ultrasonication (24 KHz) and mechanical stirring (600 rpm) for the production of biodiesel fuel was studied. Both conventional and in situ transesterification were investigated. Use of ultrasonication in conventional transesterification with methanol gave high yields of methyl esters (95%) after a short reaction time (20 min) similar to those using mechanical stirring. Higher concentrations of NaOH (2.0%) gave higher ester yields. Use of ultrasonication in conventional transesterification with ethanol gave similar yields to those using mechanical stirring but significantly lower than respective yields using methanol. In the in situ transesterification, the use of ultrasonication and mechanical stirring led to similar high yields (95%) of methyl esters after approximately 20 min of reaction time. In the presence of ethanol, use of ultrasonication led to hi...