【摘要】 <正> 钨的氧化物作为催化剂,特别适用于氧化制醛、肟等化合物,以及烯烃水合和环氧化.Schiavello和DeRossi等研究了各种钨氧化物吸附丙烯和氧的情况,以及用于丙烯氧化的活性.发现在400℃以上,蓝色氧化钨对丙烯氧化生成丙烯醛有很好的催化活性,而三氧化钨的催化活性较差,并且选择性较低.本文利用热脱附谱研究了丙烯和氧在三氧化钨表面上的吸附,并与以前研究的丙烯和氧在蓝色氧化钨上的吸附态相比较,得更多还原

【Abstract】 Thermal desorption spectroscopic method was used to measure the adsorption states of propene and oxygen on tungsten trioxide under ultra high vacuum conditions. It was found that the yellow tungsten trioxide was partly decomposed to lower valence blue tungsten oxide by heating up to 200℃ in vacuum chamber, so it was difficult to get thermal desorption spectra on pure tungsten trioxide. The thermal desorption spectra obtained in this experiment, in fact, are from the mixture of tungsten trioxide and blue tungsten oxide. Comparing with the thermal desorption spectra of pure blue tungsten oxide, we can distinguish the thermal desorption spectra of tungsten trioxide from that of the mixed sample. At room temperature, there are a chemical adsorption state for propene on tungsten trioxide and another one for ,propene on- blue tungsten oxide. These two states are both adsorption states of first order. The desorption activation energies of these two states calculated using two different methods are consistent. Average activation energies of desorption for propene on tungsten trioxide and on blue tungsten oxide are found to be 12.5 and 10.3 Kcal/mol respectively. The chemical adsorption state for oxygen on tungsten trioxide is also of first order and its activation energy of desorptipn is 7.7 Kcal/mol.It is found that the sticking coefficient for propene on blue tungsten oxide is larger than that for propene on tungsten trioxide. Finally, the adsorption sites for propene and oxygen on tungsten oxide are discussed.更多还原