摘要
在对Al-尖晶石、Cr-尖晶石、Fe-尖晶石和Ti-尖晶石等4类Ru改性的尖晶石催化剂筛选的基础上,发现Ru改性的Li Mn-尖晶石催化剂具有同Fe Mn-尖晶石催化剂类似的活性。XPS表征的结果显示,Ru改性的Li Mn-尖晶石的O1s电子结合能比Ru改性的Fe Mn-尖晶石的低1.8eV,说明前者O上的电子云密度更高。使用EXAFS(Extended X-ray adsorption fine structure)方法对Ru周围的化学环境分析发现,Ru的改性产生了具有较强氧化性的Ru O键,可有效地实现桂皮醇的催化氧化转化。此时Ru与O的配位数为5,其中与4个O原子的键长为0.1991nm,与1个O原子的键长只有0.1857nm。笔者认为,桂皮醇的催化氧化反应历程按照Michaelis-Menten模型进行,首先通过活性中心与桂皮醇形成Ru的醇化物,然后经β消除生成肉桂醛。
On the basis of the catalytic performance investigations for Al-spinel, Cr-spinel, Fe-spinel and Ti-spinel catalysts, Ru-modified LiMn-spinel exhibits similar catalytic oxidative activity as Ru-modified FeMn-spinel. The binding energy of Ois obtained from XPS characterization indicated that the electron cloud density over the O of Ru-modified LiMn-spinel was higher than that of Ru-modified FeMn-spinel owing to its Ols binding energy being lower about 1.8 eV. With the aid of EXAFS （Extended X-ray adsorption fine structure） characterization for the local environment of Ru, the Ru = O bond with more oxidative ability was generated by the modification of Ru, by which the oxidative conversion of cinnamyl alcohol can be efficiently reached. The isolated Ru species are surrounded by five O to form five Ru--O shells among which the distance for one Ru--O shells was 0. 1857 nm （one oxygen） and that for the other four Ru--O shells was 0. 1991 nm. The reaction was considered to occur according to Michaelis-Menten model, in which the Ru-alkoxide intermediate first generated between active Ru and cinnamyl alcohol, followed by β-hydride elimination to give an aldehyde.
出处
《石油学报（石油加工）》
EI
CAS
CSCD
北大核心
2005年第5期1-5,共5页
Acta Petrolei Sinica(Petroleum Processing Section)
基金
国家自然科学基金(20306009
20576045)
重大基础研究前期研究专项(2004CCA03100)资助
