Selective reduction of diolefins over the metal catalysts surface-modified by UHV treatment

特高压表面改性金属催化剂选择性还原二烯烃

• 批准号: 14550762
• 负责人: NISHIYAMA Satoru
• 金额: $ 2.37万
• 依托单位: Kobe University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2002
• 资助国家: 日本
• 起止时间: 2002 至 2003
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-14550762/
• 关键词: UHV treatment; Butadiene; Hydrogenation; TPD; Zinc oxide; Deuterium; Surface reconstruction; 選択性; パラジウム; 水素同位体

In this study, the influence of surface structure has been investigated on the activity and selectivity of hydrogenation of 1,3-butadiene. Metal and metal oxide catalysts were thermally treated under ultrahigh vacuum (UHV<10^<-7> Pa) condition (the UHV treatment). The hydrogenation activity of 1,3-butadiene was markedly enhanced over supported Pd catalysts by the UHV treatment. The selectivity of 1-butene from 1,3-butadiene was increased by the UHV treatment. Thermodynamically, 2-butenes are more stable than 1-butene. The higher selectivity of 1-butene from 1,3-butadiene over the UHV-treated Pd catalysts strongly suggests that 1,2-addition of 1,3-butadiene proceeded preferentially at the initial stage of the hydrogenation. For the formation of 2-butenes, 1,4-addition of 1,3-butadiene was requested. The adsorption intermediate for 1,4-addition requires a more flat surface of Pd, like (111) basal plane. On a roughened surface, much more 1,2-addition will be expected than 1,4-addition. The high selectivity of 1-butene on the UHV-treated Pd catalysts indicates that the surface of Pd was roughened by the UHV treatment. These results show that the UHV treatment can modified the surface structure of metals and influenced the selectivity of terminal olefins. The activity on ZnO catalysts was also significantly enhanced by the UHV treatment. It is clearly indicated that the UHV treatment was also effective for the surface modification of the metal oxide catalysts.

本研究考察了表面结构对1,3-丁二烯加氢活性和选择性的影响。在超高真空（UHV<10^<-7> Pa）条件下对金属和金属氧化物催化剂进行热处理（UHV处理）。特高压处理显著提高了负载型钯催化剂上1,3-丁二烯的加氢活性。特高压处理提高了1,3-丁二烯对1-丁烯的选择性。热力学上，2-丁烯比1-丁烯更稳定。在uhv处理的钯催化剂上，1-丁烯对1,3-丁二烯的选择性较高，这强烈表明1,3-丁二烯的1,2加成在加氢的初始阶段优先进行。2-丁烯的生成需要1,4- 1,3-丁二烯的加成。1,4加成的吸附中间体需要更平坦的Pd表面，如（111）基面。在粗糙的表面上，1,2的加入比1,4的加入要多得多。1-丁烯在特高压Pd催化剂上的高选择性表明，特高压处理使Pd表面粗化。结果表明，特高压处理可以改变金属的表面结构，影响末端烯烃的选择性。特高压处理也显著提高了氧化锌催化剂的活性。结果表明，特高压处理对金属氧化物催化剂的表面改性也是有效的。