Synthesis of porous silicas with high surface area using renewable templates

摘要

Porous silica have attracted great interest as supports in heterogeneous catalysis because they show very high specific surface areas and pore volume, and offer the possibility of incorporating a variety of heteroatoms. Non-ionic templates have been traditionally used for the synthesis of mesoporous silicas but they have drawbacks such as high cost and non-renewable nature. In this work we evaluated the use of templates that are renewable, cheap and highly available, specifically glycerol and glycerol monostearate. Tetraethylorthosilicate was employed as the silica precursor while ethanol, isopropanol and a water-ethanol mixture were used as solvents. The results show that glycerol induces microporosity while glycerol monostearate induces mesoporosity, but this latter template requires the presence of glycerol for its stabilization. Ethanol was the best solvent. Some of the obtained silicas exhibit ideal surface characteristics for a potential application as supports in heterogeneous catalysis.