Abstract: Nano-SiO2 was modified with titanate coupling agent（TMC-201） under ultrasonic dispersion. n-Butyl titanate[Ti(OC4H9)4]/nano-SiO2 catalysts were successfully prepared by loading Ti(OC4H9)4 on the surface of modified nano-SiO2 particles via impregnation method. The impacts of titanate coupling agent， temperature and time on the surface modification of hydrophilic nano-SiO2 were studied. The impacts of Ti(OC4H9)4 content, supported temperature and supported time loading on modified nano-SiO2 particles were investigated. The results indicated that the titanate coupling agent was fully grafted on nano-SiO2 when TMC-201 content was 35% of nano-SiO2, modification temperature was 90 ℃, modification time was 3.5 h. The Ti(OC4H9)4/nano-SiO2 catalysts were the best when the using of Ti(OC4H9)4 was 50% of modified nano-SiO2, supported time was 48 h at room temperature. The modified nano-SiO2 and Ti(OC4H9)4/nano-SiO2 catalysts were characterized by ICP-AES and FESEM. Compared with the Ti(OC4H9)4 catalysts, the Ti(OC4H9)4/nano-SiO2 catalysts exhibited excellent catalytic activity. The esterification time in the synthesis of the poly(trimethylene terephthalate)(PTT) with Ti(OC4H9)4/nano-SiO2 catalysts was 177 min. The viscosity was improved to 1.05 after 2 h polycondensation.

Key words: nano silicon oxide, n-butyl titanate/nano silicon oxide , catalyst, impregnation method, poly(trimethylene terephthalate)