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探讨了文题的方法,研究了反应物与催化剂浓度对凝胶化速度、颗粒大小及分布的影响。结果表明,烷氧基钛在醋酸催化作用下水解和缩聚可制备均匀透明的块状凝胶,经干燥、焙烧得到金红石型的TiO_2超细颗粒。颗粒平均粒度随水含量增加而下降;随水解底物浓度的增加而下降,然后略有上升;随醋酸浓度增加而降低。醋酸根离子浓度不仅作为催化剂,而且作力能形成Ti(OC_4H_9)_x(Ac)_y络合物的配位体而起作用,改善了颗粒粒度的均匀性。凝胶透明度与颗粒的粒度及其分布有关,而与凝胶化时间无关。本法制备的TiO_2颗粒粒度细(20～200nm)、单分散性好且纯度高。
The article discusses the method, the reactants and the concentration of catalyst on the gelation speed, particle size and distribution. The results show that titanium dioxide can be hydrolyzed and polycondensed under the catalysis of acetic acid to produce uniform and transparent massive gel. After drying and roasting, the ultrafine particles of rutile TiO2 are obtained. The average particle size decreased with the increase of water content; decreased with the increase of hydrolyzate substrate concentration, then slightly increased; decreased with the increase of acetic acid concentration. The acetate ion concentration not only acts as a catalyst, but also acts as a ligand for forming the Ti (OC_4H_9) _x (Ac) _y complex and improves the uniformity of the particle size. The transparency of the gel is related to the particle size and distribution of the particles, but not to the gelation time. The TiO 2 particles prepared by the method have fine particle size (20-200 nm), good monodispersity and high purity.