摘要
担载于Ａｌ_２Ｏ_３和ＺｒＯ_２上的Ｆｅ_２（ＣＯ）_９络合物的羰基在真空中极易脱附，在Ａｒ或Ｈ_２中２５０℃左右也可完全脱羰而成分散型催化剂．以ＺｒＯ_２为载体者在Ａｒ中低温下易发生表面歧化反应而生成ＣＯ_２，高温下生成少量ＣＨ_４．吸附于分散型催化剂上的ＣＯ在Ａｒ或Ｈ_２中均易发生岐化反应，以ＺｒＯ_２为载体者在Ｈ_２中发生加氢反应而生成ＣＨ_４，在ＣＯ加氢中其反应物除了大量ＣＯ_２外还有少量ＣＨ物．原位ＦＴ－ＩＲ谱表明以ＺｒＯ_２为载体者在Ｈｅ中或ＣＯ和Ｈ_２中均出现相当于多种中间物种的Ｃ－Ｈ振频带．根据实验结果提出了以ＺｒＯ_２为载体的Ｆｅ_２（ＣＯ）_９络合物在脱羰基过程中和在ＣＯ加氢反应过程中生成ＣＨ物种的机理．
The decarbonylation of Fe_2(CO)_ 9 complex supported on Al_2O_3 or ZrO_2,and the adsorptiondesorption and the surface reaction of CO on the dispersed Fe catalysts derived from the supported complexes have been studied by IR and programmed temperature tech niques. It is found that the carbonyls of surface complexes are easily desorbed in vacuum at room temperature.During the TPDE run of supported complexes in Ar or H2 stream, the carbonyls are fully desorbed at about 250℃.The TPDE products of Fe_2 (CO)_9/ZrO_2 complex in Ar stream are composed mainly of CO2,with less amounts of CO and CH4. The TPDE products of Fe_2(CO)_9/Al_2O_3 complex are composed mainly of CO,with less amount of CO_2. TPD-GC and TPSR-GC profiles show that CO on the supported iron catalysts derived from the Fe_2(CO)_9 complex are very easily decomposed by the disproportionation reaction. It is noticed that CO on the ZrO_2-supported iron catalyst can be hydrogenated to form hydrocarbons at temperatures above 300℃.'In situ'FT-IR spectra show that some bands of C-H stretching frequencies corresponding to various species appeared du ring the TPDE and CO hydrogenation run of ZrO_2-supported Fe_2(CO)_9 catalyst. The mechanism of CO hydrogenation for the ZrO_2-supported catalyst is proposed.This proposal involves adsorption and dissociation of CO on the catalyst prior to reaction with H_2 to form CHx and CHO intermediates.In addition,the abilities of adsorption and catalytic reaction for CO on the ZrO_2-supported iron catalyst is higher than that of the A1_2O_3-supported iron catalyst.
出处
《分子催化》
EI
CAS
CSCD
1995年第2期81-89,共9页
Journal of Molecular Catalysis(China)
基金
国家自然科学基金
关键词
络合物
铁
催化剂
吸脱附和
催化
Supported Fe_2(CO)_ 9 complexes,Decarbonylation , Dispersed iron catalysts,Adsorption-Desorption and surface reaction,Hydrogenation of CO.
