摘要
担载于Al_2O_3或ZrO_2上的Ru_3(CO)_(12)络合物在空气中易发生氧化,出现表征单核钌羰基氧化络合物的一对特征羰基带,担载于ZrO_2上者还同时出现桥式羰基带。担载络合物在真空中升温至100℃以上时也出现表征络合物发生氧化的一对特征羰基带,升温至500℃以上可以完全脱羰基而成为分散型氧化钌催化剂。担载络合物在CO中升温时,在200℃左右出现表征多种单核钌羰基氧化络合物(Ru(CO)_yO_2)的特征羰基带,升温至600～700℃时,部分表面络合物分解成分散型氧化钌催化剂。
The decarbonylation of Ru3(CO)12 complex supported on A12O3 and ZrO2 in air, vacuum and CO atmosphere has been studied by IR and TPDE-GC techniques. The oxidation of supported Ru3(CO)12 complexes in air leads to the disappearance of the carbonyl bands characteristic of the original cluster and the formation of the carbonyl bands corresponding to an oxidized complex Ru(CO)2O2; after ageing Ru3(CO)12/ZrO2 for 25 days in air, besides the terminal carbonyl bands, the bridged carbonyl band appears. Heating the supported complexes in vacuum at above 100℃, the carbonyl bands corresponding to the oxidized complex also appear, it is considered that in the absence of oxygen, the oxidizing agents are the surface OH groups on A12O3 or ZrO2- at above 500℃, the carbonyl bands diminish gradually, and the supported Ru exists in an oxidized form.When the supported complexes are heated in CO to above 200℃, three characteristic carbonyl bands corresponding to the oxidized complexes Ru(CO)yO2 appear. Accordingly, the decarbonylation process and the structure transformation of Ru3(CO)12/Al2O3 and Ru3(CO)12/ ZrO2 are proposed.
基金
国家自然科学基金
