The oxidation of thiophenol（RSH） to phenyl disulfide catalyzed by Co（Ⅱ） tetrakis（propyl-oxycarbonyl）phthalocyanine[CoPc（COOC3H7）4] in the presence of molecular oxygen was studied in synthetic bilayer membrane of vesicle, which is composed of hexadecyl 2-hydroxy-3-chloropropyl phosphate, SDS micelle, ethanol and benzene respectively. The catalytic activities followed the order of \{CoPc（COOC\}3H7）4 in the bilayer membrane>ethanol>benzene, and in the bilayer membraneSDS micelle. UV-Vis spectroscopic studies reveal that the catalytic oxidation proceeds through RS--CoPc-O2 intermediate. The catalytic activity of CoPc（COOC3H7）4 in the bilayer membrane of vesicle higher than that in the other media is considered to be attributable to the disaggregation of CoPc（COOC3H7）4 incorporated into the bilayer membrane and the easier H+ dissociation of RSH on the polar surface of the bilayer membrane bordered by bulk aqueous phase.
