Influence of reaction parameters on preparation of biodiesel from rapeseed oil using supercritical methanol

In this study, non-catalytic transesterification from rapeseed oil using supercritical methanol was carried out by varying the operation parameters such as temperature (320~365 ��C), time (0~20 min), pressure (10~35 MPa), molar ratio of oil to methanol (1: 15~60) and agitation speed (0~500 rpm). In order to evaluate the effects of reaction parameters on the content of fatty acid methyl esters (FAMEs), we carried out the study using a batch reactor. The content of FAMEs increased when the temperature increased. However, the content of FAMEs decreased with temperature above 350 ��C and time above 5 min. The content of FAMEs increased with increasing the molar ratio of methanol to oil but the content of FAMEs was slightly affected by molar ratio of oil to methanol above 1: 45 and pressure above 20 MPa. It was found that the agitation speed above 100 rpm slightly affected the content of FAMEs. The highest content of FAMEs in biodiesel (95%) was obtained under the reaction conditions: temperature of 335 ��C, time of 10 min, pressure of 20 MPa, molar ratio of 1: 45 (oil to methanol) and agitation speed of 250 rpm