Transesterification of rapeseed oils in supercritical methanol to biodiesel fuels

The transesterification reaction of rapeseed oil was investigated. Methyl esters of this oil, known as biodiesel fuel, can be produced satisfactorily in supercritical methanol without using any catalyst. Experiments in the batch reactor at 380 degrees C and 20 MPa with a molar ratio of 1 to 42 of oil to methanol led us to conclude that 120 s treatment is an appropriate reaction time to yield nearly as much methyl esters as the theoretical value. This oil is also clearly similar to those prepared by common methylesterification methods that use an alkaline catalyst in its production. The merit of this new process is that it requires just a much shorter time and that purification of the product is much simpler.