Organically modified hexagonal mesoporous silicas . Clean synthesis of catalysts and the effect of high loading and non-catalytic second groups on catalytic activity of amine-derivatised materials

Abstract

The versatility of the one-pot synthesis of organically modified silicas is shown by the preparation of materials with very high loadings (up to 4.85 mmol g^–1) and by the synthesis of bifunctional catalysts. The synthesis of these materials is shown to be very atom efficient, with all the Si species being incorporated into the product, and 98% of the template being recovered, and successfully reused. Catalytic activity is excellent, and the new catalysts outperform both the traditional silica-based catalyst, and the initial versions of these materials. The incorporation of non-polar phenyl groups has a particularly pronounced positive effect on the rate of reaction, the yield and the catalyst lifetime.