The study on preparing bio-diesel by using rapeseed oil under ultrasonic wave

In this paper,with rapeseed oil as raw material,have the reaction with methanol under ultrasonic wave with the addition of KNO3/ Al2O3 as solid base catalyst,then the bio-diesel was obtained.The ultrasonic frequency,the molar ratio of methanol to rapeseed oil and the dosage of catalyst were investigated.We found out optimum reaction conditions as following: the ultrasonic frequency was 30 kHz,the molar ratio of methanol to rapeseed oil was 7∶1,the quality ratio of cata-lyst to rapeseed oil was 2.0%,in this case,the yield was up to 94%.Then the performance of the obtained bio-diesel was investigated,which reach the current bio-diesel standards in Germany.