A thermosensitive copolymer of cobalt tetra(N-acryliccarbonyl)aminophthalocyanine (Co-TACAPc) and N-isopropylacrylamide (NIPA) was prepared through redox polymerization in aqueous solution, and its catalytic activity for oxidation of 2-mercaptoethanol was investigated. The products of Co-TACAPc and its copolymer were characterized by elemental analysis, IR, UV/vis, and TGA. The copolymer can be dissolved into most solvents, particularly into water over a wide range of pH. The copolymer also revealed a lower critical solution temperature (LCST) phenomenon at 32.6 degrees C in water; i.e., it was soluble in cold water (below 32.6 degrees C) but insoluble in hot water (above 32.6 degrees C). As a result, in contrast to Co-TACAPc, the copolymer is able to serve as a homogeneous catalyst on oxidation of 2-mercaptoethanol below 31.0 degrees C and be recovered with increasing temperature due to its lower solubility above 31.0 degrees C. (c) 2006 Elsevier Inc. All rights reserved.