TiOSO_4／SiO_2催化合成环己酮缩1,2-丙二醇

Catalytic Synthesis of Cyclohexanone 1,2-Propanediol Ketal over TiOSO_4/SiO_2

通过高温焙烧Ti(SO4)2／S1O2制得一种新型固体酸TiOSO4／SiO2,用吸附吡啶的红外光谱表征其表面酸 性,用环己酮与1,2-丙二醇的缩酮化反应表征其酸催化活性。结果表明:催化剂表面存在明显的Bronsted酸中心,对缩 酮化反应的催化活性好,且催化活性随灼烧温度的升高而降低。并获得优化条件如下:醇酮摩尔比1．2,催化剂用量为 酮质量的4％,反应时间55 min,反应温度140℃,甲苯作带水剂,缩酮产率为88％。催化剂易回收,可重复使用多次。

A new type of solid acid catalysts TiOSO4/SiO2 was prepared by calcination of Ti（SO4）2/SiO2 at high temperature. The acid property was characterized by FT-IR spectra of pyridine adsorbed on its surface. And the catalytic activity was determined by ketalization between cyclohexanone and 1,2-propanediol. The results showed that the catalysts had Bronsted acid centers and the catalytic activity decreased with the rising of calcination temperature. The yield of ketalization was 88 % under the optimum conditions as follow： calcination temperature 450℃, the molar ratio of 1,2-propanediol to cyclohexanone 1.2, the amount of catalyst 4% upon the mass of cyclohexanone, reaction time 55 min,reaction temperature 140℃, toluene used as entrainer. And the catalyst could be recovered easily and reused for many times.