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Transesterification of triolein in excess methanol oversodium-loadedcatalysts prepared from Na-ion exchange with zeolites at a relativelylower reaction temperature, namely, at 60 °C, is studied in thiswork. Two zeolites, i.e., as-synthesized ZeoliteMCM-22 and commercial Zeolite HY (CBV-780), are employed in this study.Althoughboth zeolites show to some extent the capability of catalyzing transesterificationof triolein in methanol to biodiesel, the resulting yields are onlyca. 90% for CBV-780 after a 40-h reaction and 16.3% for MCM-22 aftera90-h reaction. In contrast, the conversion yields are much improvedwith Na-ion exchange to the surface of zeolite catalysts. For example,the yields of triolein to biodiesel have reached 98% and 99% withina 5.5-h reaction, respectively, using the NaOH-treated CBV-780 andMCM-22 catalysts, even if these NaOH-treated catalysts become amorphousand have suffered a loss of the Brunauer–Emmett–Tellersurface area. Furthermore, no saponification was observed using theseNaOH-treated catalysts. [ABSTRACT FROM AUTHOR]