Metallophthalocyanine has attracted considerable attention as oxidation catalyst because its structure similar to the active center of cytochrome P-450

and it can promote many reactions through oxidase-like

catalase-like

as well as peroxidase-like mechanism

whereas it has the following problems:low solubility

high aggregation tendency

difficulty in catalyst recovery and recycling

which restrict its further application as catalyst.Poly(N-isopropylacrylamide) (PNIPAAm) is a typical thermosensitive polymer

and it can be homogeneous below its lower critical solution temperature (LCST) and completely precipitated above LCST

which makes it become an attractive polymer support for catalyst. A novel reactive and aqueous soluble metallophthalocyanine derivative

cobalt tetra(2

4-dichloro-1

3

5-triazine)aminophthalocyanine (Co-TDTAPc)

was synthesized by the modification of cobalt aminophthalocyanine with 2

4

6-trichloro-1

3

5-triazine and immobilized on PNIPAAm by covalent bond to obtain a thermosensitive polymer catalyst

PNIPAAm-g-Co-TDTAPc. The polymer catalyst was characterized by UV-Vis spectrometer in ethanol and THF

and the results showed that PNIPAAm-g-Co-TDTAPc had characteristic absorption peaks of cobalt phthalocyanine (B band: 280～330 nm; Q band: 620～700 nm) in both ethanol and THF

while PNIPAAm had no absorption in these area

which proved that the Co-TDTAPc had been successfully grafted on PNIPAAm.The thermal stability of the polymers were also tested by heating from room temperature to 600℃ at a rate of 20 K/min in a nitrogen environment with flow rate of 100 mL/min.The results indicated that the beginning decomposition temperature of PNIPAAm-g-Co-TDTAPc was 407℃

which confirmed that the polymer catalyst had high thermal stability.The solubility of small molecular cobalt phthalocyanine

PNIPAAm and PNIPAAm-g-Co-TDTAPc was investigated in different solvents. The results showed that PNIPAAm-g-Co-TDTAPc could dissolve in water and most organic solvents

while the small molecule cobalt phthaloyanine only dissolve in DMSO and DMF

which proved that the solubility of cobalt phthalocyanine was improved significantly after immobilization on PNIPAAm. The thermosensitive property of PNIPAAm-g-Co-TDTAPc was investigated by cloud point measurements

and the results showed that PNIPAAm-g-Co-TDTAPc exhibited excellent thermosensitive property in aqueous solutions

and its LCST was 34.5℃.The LCST of PNIPAAm-g-Co-TDTAPc in the mixture of water and organic solvents (ethanol and DMF) was also studied

and the experimental results showed that the LCST of PNIPAAm-g-Co-TDTAPc first decreased when the volume fraction of ethanol in mixed solvents increased below 27.5% and then sharply increased above 59.5% until the thermosensitivity of PNIPAAm-g-Co-TDTAPc disappeared. The experimental results in DMF/water mixed solvents were similar to those in water/ethanol. Furthermore

the catalytic activity of PNIPAAm-g-Co-TDTAPc on 2-mercaptoethanol was investigated by the consumption of oxygen at different temperature and pH 11.The results indicated that PNIPAAm-g-Co-TDTAPc had a high catalytic oxidation activity on 2-mercaptoethanol

and the reaction rate was first increased with the temperature increasing and then rapidly decreased when temperature was over LCST due to the precipitation of this catalyst from the solution. In conclusion

a novel high efficient polymer catalyst was prepared

which has both good solubility and excellent thermosensitive properties. Based on the above properties

it can be served as a homogeneous catalyst and separated just by heating

having potential applications in the fields of organic synthesis and degradation of organic pollutants.