日本ゼオライト学会　刊行物 Publication of Japan Zeolite Association

A hybrid mesoporous silica (HME) with ethynylene (–CH=CH–) groups and 2 dimensional hexagonal (2D-hex) structure is synthesized from bis (triethoxysilyl) ethylene ((EtO)₃–S–CH=CH–Si(OEt)₃) in the presence of structure directing reagent. The ethynylene sites exposed on the surface were reacted with benzocyclobutene to produce surface-protruded phenylene groups, which were stabilized through C–C bonds onto the surface (Ph-HME). The phenylene groups in Ph-HME were easily sulfonated by treatment with concentrated sulfonic acid to construct a stable and strong solid acid catalyst (Ph–SO₃H HME). Ph–SO₃H HME showed higher catalytic activity than other acid catalysts in Pinacol rearrangement, Beckmann rearrangement, Friedel-Crafts acylation and alkylation, olefin hydration and ether formation from carbonic acid and alcohol. No leaching of sulfur into the reaction solutions nor decrease of Ph–SO₃H HME in the amount of sulfur was observed, in addition to the preservation of the original 2D-hex mesoporous structure. As a result, no deactivation was observed during repeated reactions, and Ph–SO₃H HME demonstrated stable activity for a repeat use.