Three types of TiO2.Al2O3Â gels ([TiO2]/[ Al2O3]=1/4 in mol) wre prepared by hydrolysis of Al(OC4H9sec)3and Ti(OC3H7iso)4Â in an n-propanol solution with acid catalyst. Their physical properties and catalytic on the formation of polyethylene glycol ester were investigated. The wet gels were dried (Xerogel), immersed in surfactant solution before dying (Modified Gel), or supercritically extracted with CO2Â at 60oC and 24 Mpa for 2h (Aerogel). The pore size and pore volume of these gels hardly decreased after calcinations at 800oC, atlhough those values of the xerogel remarkably decreased after calcination up to 800oC. The thermal stability of the microstructure of mesoporous titania-alumina is improved by surfactant immersion of supercritical extraction. The aerogel had the highest catalytic activity for the reaction of polyethylene glycol and stearic acid. The effects preparation methods on the microstructure and catalytic activity of the gels were disccussed.
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