Acceleration of catalytic activity of calcium oxide for biodiesel production.

This research was aimed at studying the acceleration of the catalytic activity of calcium oxide (CaO) for developing an effective heterogeneous catalyst for biodiesel production by the transesterification of plant oil with methanol. CaO was activated by pretreatment with methanol and was used for the transesterification reaction. The activation and transesterification reaction conditions were examined. The obtained optimal reaction conditions were 0.1-g CaO, 3.9-g methanol, 15-g rapeseed oil, and 1.5-h activation time at room temperature that provided methyl ester in approximately 90% yield within a reaction time of 3h at 60 degrees C. The activation mechanism was also investigated, and the proposed mechanism is as follows. By pretreatment with methanol, a small amount of CaO gets converted into Ca(OCH(3))(2) that acts as an initiating reagent for the transesterification reaction and produces glycerin as a by-product. Subsequently, a calcium-glycerin complex, formed due to the reaction of CaO with glycerin, functions as the main catalyst and accelerates the transesterification reaction.

Development of heterogeneous base catalysts for biodiesel production.

Investigations were conducted on heterogeneous base catalysts for the transesterification of oil aimed at effective production of biodiesel. Thirteen different kinds of metal oxides containing calcium, barium, magnesium, or lanthanum were prepared as catalysts. Their catalytic activities were tested for transesterification at 60 degrees C with a 6:1 molar ratio of methanol to oil and a reaction time of 10h. The calcium-containing catalysts - CaTiO3, CaMnO3, Ca2Fe2O5, CaZrO3, and CaO-CeO2 - showed high activities and approximately 90% yields of methyl ester. Furthermore, catalytic durability tests were performed by repeating the transesterification reaction several times with the calcium-containing catalysts recovered from the previous reaction mixture. It was found that CaZrO3 and CaO-CeO2 show high durability and have the potential to be used in biodiesel production processes as heterogeneous base catalysts.