Catalytic production of biodiesel from corn oil by metal-mixed oxides

Abstract

The present study investigates the transesterification of corn oil with methanol over two oxides of MgO and ZnO at 65 ͦC and 1 atm. These two catalysts have been prepared via a conventional co-precipitation process. As for MgO, the corresponding mixed metal nitrate solution has been mixed and heated at the presence of urea. ZnO has also been synthesized by co-precipitation of metal acetate at the presence of oxalic acid and ethanol. The catalysts then have been characterized by means of X-Ray Diffraction (XRD) and Scanning Electron Microscope (SEM). XRD results indicate high purity for both catalysts. Also, catalytic activity has been evaluated in methanol reflux temperature through corn oil transesterification, with the impacts of reaction variables, like catalyst amount, methanol/oil molar ratio, and reaction time on biodiesel yield, investigated by means of HNMR spectrum. Under appropriate transesterification conditions at 65 °C (catalyst amount= 5%, methanol/ oil ratio= 20, and reaction time= 10 hr), an ME content of 62.61% can be achieved, using MgO catalyst. Similarly, the experiments have been repeated to achieve the best yield, using ZnO catalyst, with the highest rate, equal to 53.1%, obtained in 9% of catalyst and methanol/oil ratio of 30 over 10 hr. Furthermore, reusability of ZnO and MgO has been evaluated in transesterification reaction.