关键词: N-羟基邻苯二甲酰亚胺, 固载化, 交联聚苯乙烯微球, 分子氧, 催化氧化

Abstract: The immobilized N-hydroxyphthalimide (NHPI) catalyst was prepared with cross-linked polystyrene (CPS) microspheres as matrix by molecular design. The chloromethylated cross-linked polystyrene (CMCPS) microspheres were first prepared, and then phthalic anhydride (PA) was bonded onto them through the esterification reaction between the chloromethyl groups on the microspheres and carboxyl group of trimellitic anhydride (TMA), obtaining CPS-PA microspheres. Finally, the bonded PA reacted with hydroxylamine hydrochloride, resulting in CPS-NHPI microspheres, on which NHPI groups were immobilized. The CPS-NHPI microspheres were characterized, and used in the oxidation of toluene and cyclohexanol with molecular oxygen, respectively. The catalytic activity of CPS-NHPI was examined, and catalytic oxidation mechanism investigated. The results show that the reaction of CMCPS microspheres with TMA is a key step, which can be carried out smoothly with triethylamine as acid-binding agent and polar solvent N,N-dimethylacetamide at 110℃, the conversion rate of chloromethyl on CMCPS microspheres can reaches 73%, and the CPS-NHPI microspheres with a NHPI immobilized capacity of 2.25 mmol/g can be gained. The combinatorial catalyst system constituted by CPS-NHPI microspheres and a little of Co(OAc)2 displays fine catalytic activity in the oxidation reactions of toluene and cyclohexanol with molecular oxygen as oxidant, and the catalytic oxidations may undergo the mechanism of free radical chain reaction.

Key words: N-hydroxyphthalimide, immobilization, cross-linked polystyrene microsphere, molecular oxygen, catalytic oxidation