A continuous reactor was used to examine the effect of pressure on biodiesel production using a supercritical tert-butyl methyl ether (MTBE) at the pressure range of 10-30 MPa and temperature range of 300-400°C. The effect of pressure on reaction rate as well as final product composition was negligible for the conditions employed here. This negligible effect could be explained by the almost constant density of MTBE. The pre-exponential factors and activation energy for each reaction step as well as its reverse reaction have been determined.
Biodiesel is defined as the mono-alkyl esters of vegetable oils (both edible and non edible) or animal fats, obtained by transesterifying oil or fat with an alcohol. In this research, biodiesel is produced by in situ transesterification (direct transesterification) method from the seed of rubber tree using KOH as a catalyst. The influence of seed to methanol mass ratio, reaction time, temperature, seeds sizes, and catalyst loading was investigated. Important properties of biodiesel such as free fatty acid (FFA), viscosity, pour point, density etc were also investigated. The result showed that the best ratio of seeds to methanol was 1:6 (10 g seeds with 60 g methanol), 120 min reaction time at 60°C reaction temperature, and catalyst loading of 3.0 g with 150 µm seeds size. The maximum yield obtained was 96 %, and also most of the properties obtained were in agreement with the standards and with other FAMEs. This study supports the production of biodiesel from the rubber seeds using in situ (direct) transesterifcation method from the seeds as an alternative to diesel fuel.