Preparation and characterization of a novel class of solid acid catalyst Nafion/SiO2

Due to its superacidic character, high thermal stability and chemical resis tance, Nafion(R) NR50 is a very promising catalyst for a wide range of acid - catalyzed reactions. However, its application is often limited by its ex tremely low specific surface area. A new class of solid acid catalysts Nafi on/SiO2 with meso - pore structure has been developed using an in situ sol - gel technique, where solutions of Nafion resin were mixed with soluble si licon sources of tetraethylorthosilicate to form a gel. The gel was then dr ied to give a clear hard glass - like material. These new porous materials showed significantly enhanced activity due to increased accessibility of th e Nafion resin - based acid sites. BET, MR, TG, SEM and EDX indicated that Nafion resin nanoporrticles were completely trapped and highly dispersed wi thin a porous silica network. NH3 - TPD disclosed that the materials have f our groups of acidic sites and that the thermal stability Of SO3H groups wa s different.