用 XAFS(X-ray absorption fine structure)分析了由溶胶-凝胶、液相浸渍和化学气相沉积等三种方法制备的二氧化钛和二氧化硅复合氧化物的 Ti K 边结构．结果表明：溶胶-凝胶法制得的复合氯化物中的钛分散很好，液相浸渍法次之，而化学...用 XAFS(X-ray absorption fine structure)分析了由溶胶-凝胶、液相浸渍和化学气相沉积等三种方法制备的二氧化钛和二氧化硅复合氧化物的 Ti K 边结构．结果表明：溶胶-凝胶法制得的复合氯化物中的钛分散很好，液相浸渍法次之，而化学气相沉积法最差，不论哪种方法，随钛含量(或钛硅原子比)的增加，边前特征峰 A2降低，钛的第一配位层 Ti-O 的配位数和键长增加；在复合载体中既有钛中心对称的八面体6配位 TiO_6的结构也有钛中心对称性差的四面体4配位 TiO_4或五面体5配位结构，并且随钛含量增加，钛的局域结构越来越接近锐钛矿型二氧化钛，根据 XAFS、XRD、IR 表征结果，提出了钛硅复合氧化物模型。展开更多
A highly efficient Pd\|BMImCl/TiO\-\%y\%\|SiO\-\%x\% catalyst system synthesized through sol\|gel method from palladium complex, ionic liquid, titanate and silicate esters was found for the oxidative carbonylation of ...A highly efficient Pd\|BMImCl/TiO\-\%y\%\|SiO\-\%x\% catalyst system synthesized through sol\|gel method from palladium complex, ionic liquid, titanate and silicate esters was found for the oxidative carbonylation of amines. The catalyst efficiency was much higher than that reported in previous papers and the TOF number reached to 10 372 when catalyst 0.05%Pd\|4.6%BMImCl/TiO\-\%y\%\|SiO\-\%x\% was used. The usability of ionic liquid was the key point for preparation of this catalyst system because of its high dissolvability to palladium complex and affording appropriate micro\|environment for the reaction. The synergism among palladium complex, ionic liquid, titanate and silicate was the main reason for the high catalytic activity of the catalyst system. BET, AES and XRD were used to characterized the catalysts in detail.展开更多
文摘用 XAFS(X-ray absorption fine structure)分析了由溶胶-凝胶、液相浸渍和化学气相沉积等三种方法制备的二氧化钛和二氧化硅复合氧化物的 Ti K 边结构．结果表明：溶胶-凝胶法制得的复合氯化物中的钛分散很好，液相浸渍法次之，而化学气相沉积法最差，不论哪种方法，随钛含量(或钛硅原子比)的增加，边前特征峰 A2降低，钛的第一配位层 Ti-O 的配位数和键长增加；在复合载体中既有钛中心对称的八面体6配位 TiO_6的结构也有钛中心对称性差的四面体4配位 TiO_4或五面体5配位结构，并且随钛含量增加，钛的局域结构越来越接近锐钛矿型二氧化钛，根据 XAFS、XRD、IR 表征结果，提出了钛硅复合氧化物模型。
文摘A highly efficient Pd\|BMImCl/TiO\-\%y\%\|SiO\-\%x\% catalyst system synthesized through sol\|gel method from palladium complex, ionic liquid, titanate and silicate esters was found for the oxidative carbonylation of amines. The catalyst efficiency was much higher than that reported in previous papers and the TOF number reached to 10 372 when catalyst 0.05%Pd\|4.6%BMImCl/TiO\-\%y\%\|SiO\-\%x\% was used. The usability of ionic liquid was the key point for preparation of this catalyst system because of its high dissolvability to palladium complex and affording appropriate micro\|environment for the reaction. The synergism among palladium complex, ionic liquid, titanate and silicate was the main reason for the high catalytic activity of the catalyst system. BET, AES and XRD were used to characterized the catalysts in detail.
