Synthesis of polymeric materials in mesoporous silica templates and their catalytic functionalization

Abstract

The work presented the aspects of ordered mesoporous polymers: synthetic strategy for ordered mesoporous polymers, their structural characterizations and catalytic applications with their functionalizations. Since the ordered mesoporous carbon CMK-1 was first synthesized in 1999 via the template-directed synthesis strategy using ordered mesoporous silica as templates, various kinds of mesoporous materials were synthesized through template synthesis using mesoporous silica. In this work, mesoporous organic materials were synthesized via free-radical polymerization of crosslinkable olefinic monomers inside porous templates. The synthesis process has been employed to generate ordered mesoporous structures through use of a mesoporous silica template, KIT-6. The polymerization reaction proceeded with heating at $150^\circ C$ after initiation with AIBN. The resultant polymeric materials were characterized after template extraction using HF solution. Characterization results demonstrated that the polymeric materials retained a cubic Ia3d mesoporous structure only when the template pore diameters exceeded 5 nm, even if highly crosslinkable monomers were incorporated. The polymeric structure collapsed unless the template pore diameters were sufficiently larger than the distance between crosslinking points. In addition, structural integrity was maintained only if the mesopore walls were hydrophobically functionalized via silylation. Under optimal replication conditions, the ordered mesoporous polymeric materials exhibited a very narrow pore size distribution and a high specific surface area $(619m^2g^{-1})$ that reflected the qualities of the original silica template. Such mesoporous polymeric materials could be functionalized via copolymerization with other functional monomers or via organic reactions. An acid catalyst was prepared for esterification reaction of benzyl alcohol with hexanoic acid via reaction of poly-DVB material with sulfuric acid. And heterogeneous m...