A “one-step” sulfonic acid PMO as a recyclable acid catalyst

•Sulfonic acid-functionalized PMOs are synthesized by in situ and post-synthesis oxidations.•In situ functionalized PMO shows a well-ordered mesostructure and a narrow pore size distribution.•Sulfonated PMO materials are active in the esterification of acetic acid with benzyl alcohol.•In situ functionalized PMO is an efficient, robust, non-swelling, and recyclable catalyst.

The synthesis and catalytic activity of a new sulfonic acid-functionalized periodic mesoporous organosilica (PMO) obtained by an in situ oxidation process have been reported. This material was prepared by co-condensation of a homemade thiol-functionalized bis-silane precursor (EtO)3Si-R-Si(OEt)3 (R = CH2CHSH) with 1,2-bis(triethoxysilyl)ethane (BTEE) in the presence of a nonionic triblock co-polymer. Thiol groups were oxidized either in situ during the formation of the mesostructure, or by a post-synthesis oxidation of the solid material. The in situ generated sulfonated PMO material had a well-ordered hexagonal mesoporous structure and a narrow pore size distribution. The sulfonic acid concentration of these materials was in the range of 0.85–1.48 mmol H+ g−1. The catalytic performance of these sulfonic acid-functionalized materials was evaluated and compared with the commercial resin Amberlyst-15 in the esterification of acetic acid with benzyl alcohol. The in situ sulfonated PMO has shown to be an efficient, robust, and recyclable catalyst in acid-catalyzed reactions throughout consecutive catalytic cycles.

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