Supported Nafion catalyst for 1-pentanol dehydration reaction in liquid phase

Silica-supported and alumina-supported Nafion catalysts that differ in surface area and Nafion contents were prepared using an impregnation technique. Liquid-phase dehydration of 1-pentanol to produce di-n-pentyl ether was used to measure their catalytic activity. A reproducible impregnation method was found, which considers a controlled evaporation of water and alcohols and a further washing with methanol before final drying. Only silica-supported catalysts were active for the alcohol dehydration reaction. Acid capacity and 1-pentanol conversion, increased on increasing the initial amount of Nafion. Despite 1-pentanol conversion obtained for all silica-supported catalysts were lower than that obtained for commercial Nafion NR50, turnover numbers were always better for impregnated catalyst. A maximum turnover number was found for 26 wt% loading of Nafion on silica. A kinetic model in terms of compounds activities describes satisfactorily the experimental kinetic data. It is based on a mechanism in which the rate-determining step is the surface reaction between two adjacent adsorbed 1-pentanol molecules. The apparent activation energy was found to be in the range 106–128 kJ mol−1.