from first principles PP-I-1

OY-IV-5Could Calcination Temperature Stand for CaO CatalystReal Activation Act in Transesterification of Sunflower Oil?Randjelovic M. 1 , Stojkovic N. 1 , Ljupkovic R. 1 , Marinkovic M. 1 , Putanov P. 2 , Zarubica A. 11 University of Nis, Faculty of Science and Mathematics, 18000 Nis, Serbia2 Serbian Academy of Science and Arts, 11000 Belgrade, Serbiazarubica2000@yahoo.comIn heterogeneous catalytic approach in biodiesel production, CaO is very popular due to itsrelatively high catalytic activity. Moreover, a right activation act may improve efficiency andrentability of commercial CaO. Commercial CaO and different catalysts prepared by usingcalcination temperatures in the range 500-1000°C have been studied comparatively inbiodiesel synthesis process. Appropriate methods were used in order to characterize catalysts.Catalytic efficiency was tested in transesterification of sunflower oil under typical reactionconditions: temperature 65°C, pressure 1 atm, oil-to-methanol molar ratio = 6:1, and using 1%of CaO for 5h. Textural features show no substantial differences especially in case of CaOcalcined at 500 and 900°C. Namely, results show that CaO treated at higher temperaturepossesses a relatively high surface area (4.3 m 2 /g) and total pore volume (0.02 cm 3 /g), as wellas dominant meso-pores of 60 nm in size. XRD analysis proved that all calcined CaOcatalysts consisted of pure oxide unlike uncalcined commercial CaO with unknown thermalhistory. Temperatures above 700°C do not affect grain size or even undesirable sintering. Asthermal analysis exhibits, the higher the calcinations temperature, the lower the remnant ofwater (surface or constitutional one), particularly compared to commercial CaO thermallyuntreated. The authors suggest the presence of weak base sites on the surface of lowtemperatureactivated CaO catalysts, while a surface of well dehydrated CaO catalysts(calcined at 900 and 1000°C) consist of strong basic sites. SEM images reveal nano-scalespongy-like morphology of CaO catalyst treated at higher temperatures. CaO calcined athigher temperatures (900 and 1000°C) applied in catalysis of the transesterification ofsunflower oil for biodisel, presented excellent catalytic efficiency with the yield of 90.9%.Such activated CaO could be very attractive as a heterogeneous base catalyst of well-definedmorphology, low cost and easy-to-prepare material, with a potential application in othercatalytic fields on the industrial level.Acknowledgements: The authors wish to thank to Project of Serbian Academy of Science andArts (Project leader: Academician Paula Putanov) for the financial support.106