Direct synthesis of acid–base bifunctionalized hexagonal mesoporous silica and its catalytic activity in cascade reactions

A series of efficient acid–base bifunctionalized hexagonal mesoporous silica (HMS) catalysts contained aminopropyl and propanesulfonic acid have been synthesized through a simple co-condensation by protection of amino group. The results of small-angle XRD, TEM, and N2 adsorption–desorption measurements show that the resultant materials have mesoscopic structures. X-ray photoelectron spectroscopies, elemental analysis (EA), back titration, 29Si NMR and 13C NMR confirm that the organosiloxanes were condensed as a part of the silica framework. The resultant catalysts exhibit excellent acid-basic properties, which make them possess high activity for one-pot deacetalization–Knoevenagel and deacetalization–nitroaldol (Henry) reactions.

Graphical abstractA series of efficient acid–base bifunctionalized hexagonal mesoporous silica (HMS) catalysts have been synthesized. The novel catalysts possess high activity for cascade reactions.Figure optionsDownload full-size imageDownload high-quality image (67 K)Download as PowerPoint slideResearch highlights► Acid-base bifunctionalized hexagonal mesoporous silica catalysts. ► Synthesized through protection of amino group. ► Exhibit excellent acid-basic properties. ► Possess high activity for one-pot cascade reactions.