Injecting superheated C1 and C3 alcohol supports towards non-catalytic semi-continuous conversion of Hevea brasiliensis oil into biodiesel

Biodiesel synthesis from rubber seed oil using superheated methanol and 2-propanol was comparatively evaluated in this study. For conversion, the alcohol was pre-heated far beyond its boiling point and then allowed to flow into heated oil in the reactor, where spontaneous conversion takes place, before being collected with the formed product after cooling. Batch studies were used to estimate the suitable range of parametric values for central composite design optimization. Product separation requires only distillation for alcohol removal, while formed glycerol is recovered from the unreacted oil via centrifugation. Methanol converts the oil faster than 2-propanol but propyl esters have higher thermal stability. Optimal fuel yields of 98.59% and 96.92% were obtained using initial oil mass of 400 g at preheat temperatures of 130 degrees C and 140 degrees C when reaction temperatures were 240 degrees C and 260 degrees C for 7 min and 8 min respectively with methanol and 2-propanol. Fuel characterization shows its suitability for use as biodiesel according to standards set for commercial biodiesel. Boasting a high rate of conversion and simple operation along with easy product separation, the superheated conversion approach described here can therefore be scaled up for commercial application and even made continuous with some appropriate modifications.

Automated summary

This study comparatively evaluated the synthesis of biodiesel from rubber seed oil using superheated methanol and 2-propanol. The results showed that methanol converted the oil faster than 2-propanol, but propyl esters had higher thermal stability. The optimal operating conditions were determined as reaction temperatures of 240 degrees C and 260 degrees C for 7 minutes and 8 minutes, respectively.