PALM OIL BASED FATTY ALCOHOLS TEMPLATED MESOPOROUS SILICA AND SILICA SPHERES

Abstract

Mesoporous silica xerogels with wormhole-like pore structure were successfully synthesized using a series of surfactantless oil-in-water emulsion at room temperature. The surfactantless emulsion systems consisted of palm-oil derived fatty alcohols having several carbon chain lengths to act as mesoporous templates in place of commercial surfactants in a direct base–acid catalyzed sol–gel method. This method allowed direct decomposition of fatty alcohols in situ during calcination process to create mesoporosity in the materials. The mesoporous silica xerogels exhibited relatively high surface area at ca. 505 m2/g and pore sizes at ca. 8 nm to 13 nm as the carbon chain lengths were varied. The pore size obtained in this study was larger than the conventional MCM-41 materials (at ca. 2 nm). The mesopores were generated from the interstices of the primary particles (framework-confined porosity) and secondary particles (textural porosity). Furthermore, by changing the co-solvent amount and oil/water ratio, surfactantless oil-in-water microemulsions were obtained. These microemulsions were useful in the synthesis of monodispersed silica spheres. The size of the silica spheres could be controlled at two different size clusters, ca. 50–200 nm and at ca. 500 nm.