摘要
非晶钛硅复合氧化物不同于钛硅分子筛,由于其不受分子固定的骨架结构限制,故其活性中心钛含量以及孔的结构易被调控,且具有很好的催化活性和再生性能。以双氧水为氧源,非均相催化环氧化制备精细化学品,对环境无污染,符合现在绿色化工生产工艺的要求。本文以硅酸钠为硅源,硫酸钛为钛源,采用沉淀法制备不同TiO_2-SiO_2复合氧化物。表征结果显示:TiO_2-SiO_2复合氧化物为非晶态结构,样品中存在Ti-O-Si键。在温和的条件下,以双氧水为氧化剂,乙腈为溶剂、TiO_2-SiO_2复合氧化物为催化剂进行催化氧化苯乙烯生成环氧苯乙烷,结果表明:在反应温度60℃、反应时间1h、苯乙烯15mmol、氢氧化钠0.1g和苯乙烯与氧化剂比例为1:6的条件下,苯乙烯转化率为60%,选择性为94%。
Amorphous titanium silicon composite oxides are different from titanium silicon molecular sieve,because they are not affected by the structure of molecular sieve,and the titanium content and pore structure is easy to control,and which have the excellent catalytic activity and regeneration performance.TiO_2-SiO_2 was prepared by using sodium silicate as silicon source and titanium sulfate as titanium source.TiO_2-SiO_2 with different TiO_2contents were prepared by coprecipitation and the results of characterization showed that they were noncrystalline structure.The heterogeneous catalytic oxidation of styrene was investigated using hydrogen peroxide solution as oxidizing agent and acetonitrile as solvent under mild conditions.The optimized reaction conditions are shown as follows:15mmol of styrene,sodium hydroxide amount 0.1g,6:1 molar ratio of H_2O_2 and styrene,reaction time 1h and reaction temperature 60 ℃.The conversion of styrene is 60%and the selectivity of epoxy ethylbenzene is 94%,respectively.
引文
[1]Liu G,Liu Y,Yang G,et al.Journal of Physical Chemistry.2009,113(21):9345-9351.
[2]葛金龙,王传虎,陶云龙.光谱实验室,2011,28(5):2291-2294.
