Water-tolerant catalysis of a silica composite of a sulfonic acid resin, Aciplex Original Research Article

A silica composite of a perfluorocarbonsulfonic acid resin, Aciplex, has been used as a solid acid catalyst for a variety of reactions concerning water. The Aciplex–SiO2 composite containing 20 wt% Aciplex has a surface area of 1.3 m2 g−1 and possesses an ion-exchanged capacity of 0.46 meq. g−1 after pretreatment at 423 K, which is higher than that of 13 wt% Nafion–SiO2 (0.12 meq. g−1). The acid strengths estimated from an initial heat of adsorption of NH3 were similar for these polymer resin composites. It was found that the Aciplex–SiO2 was more active than typical solid acids such as Cs2.5H0.5PW12O40, H-ZSM-5, and SO42−/ZrO2 for hydrolysis of ethyl acetate in excess water and esterification of acrylic acid with 1-butanol, while it was less active than Cs2.5H0.5PW12O40 for N-alkylation of acrylonitrile with 1-adamantanol and solid–solid hydrolysis of 2-naphthyl acetate. The Aciplex–SiO2 was superior in activity to Nafion–SiO2 for all the above reactions and in thermal stability. These results indicate that Aciplex–SiO2 is a promising solid acid catalyst for reactions involving liquid phase water.