Micrometer-sized silica gel was modified chemically by using γ-methacryloxypropyl trimethoxysilane(MPTMS) as a coupling agent

and double bond was introduced onto silica gel particle surface.4-vinylpyridine was grafted from silica gel surfaces

and grafting particles P4VP/SiO2 was prepared.The coordination between grafted P4VP and cupric ions was performed

and the complex catalyst P4VP-Cu(Ⅱ)/SiO2 was obtained.The chemical structure and thermal stability of the product were characterized with infrared spectrum(IR) and thermogravimetry(TG) respectively

and the morphology of grafting particles P4VP/SiO2 was observed with scanning electron microscopy(SEM).The graft polymerization is a key step for the preparing of the complex catalyst P4VP-Cu(Ⅱ)/SiO2

so the effects of various factors on the graft polymerization were examined.The suitable conditions of reaction are as follows: a monomer concentration of 15~20 wt%

an initiator concentration of 2wt%(percent of monomer amount)

at 80 ℃ and for 7 h.Under these conditions

the grafting degree of P4VP could get up to 25 g/100 g.The results of TG determining showed that the complex P4VP-Cu(Ⅱ) grafted onto SiO2 has much better heat stability than the ungrafted complex P4VP-Cu(Ⅱ).