Development and characterization of a microfiltration membrane catalyst containing sulfonated polystyrene grafts

Esterification catalysis using functionalized membranes

“…The RPES membrane was modified into catalytic membrane by a simple three step procedure. First, the internal surface of the membrane was mildly sulfonated by contact with dilute (0.5N) sulfuric acid [26]. The immobilized sulfonic acid groups act as the initiator for cationic polymerization of styrene.…”

“…Finally, the polystyrene grafts were formed in the membrane pores, and were activated by treatment with sulfuric acid (0.5N) solution. A more detailed description of the preparation conditions appears in a previous paper [26]. The results presented in this paper for the membrane catalyst are accomplished through the cationic route.…”

“…The convective flow of reagents through the dry membrane was maintained throughout the experiment. The complete experimental setup has been described in our previous work [26]. The feed tank was washed with water (pH 7) and dried completely before any convective run.…”

“…Catalytically active microfiltration (0.1-1 mm pore size) membranes containing sulfonated polystyrene grafts have demonstrated potential as heterogeneous strong acid catalysts [26]. The acid sites located on the polymer grafts are rapidly accessible to the reactive species in a convective flow type configuration.…”

“…The objective of this work was to apply novel membrane catalysts, developed in our laboratory [26], to acid catalyzed reaction systems. The esterification of ethanol and acetic acid (A.A.) to form ethyl acetate was used as the test reaction, and comparisons were made with standard available acid catalysts.…”