A series of Ca/SBA-15 samples with Ca/Si atomic ratios of 0 1 02 03 04 and 05 were prepared by using a one-pot synthesis method They were used in the transesterification of sunflower oil with methanol For comparison 0 3Ca/SBA-15 was also synthesized by an incipient impregnation method (0 3Ca/SBA-15-IM) Small-angle XRD N-2 adsorption TEM SEM TG-DTA FTIR CO2-TPD techniques were used to determine the textual structure and physicochemical properties of Ca/SBA-15 samples The mesoporous structure of SBA-15 was well preserved with Ca/S1 ratios up to 05 Compared with 0 3Ca/SBA-15-IM sample the Ca/SBA-15 showed not only a better calcium species distribution but also higher BET surface area and larger medium basic sites A biodiesel yield of as high as 99 1% was achieved on the 0 5Ca/SBA-15 catalyst at a reaction temperature of 200 C for 8 h In the meantime no deactivation was found after five cycles on Ca/SBA-15 sample prepared by one-pot synthesis method in the transesterification reaction which showed a much better stability than that of prepared by conventional impregnation method Besides a water content of up to 5% and/or free fatty acids (FFAs) content of 3% did not affect the catalytic activity of Ca/SBA-15 catalyst in the transesterification reaction (C) 2010 Elsevier B V All rights reserved