STEADY-STATE KINETICS OF THE CO-N2O REACTION OVER AN ALUMINA-SUPPORTED RHODIUM CATALYST

被引:110
作者
MCCABE, RW
WONG, C
机构
[1] Physical Chemistry Department, General Motors Research Laboratories, Warren
关键词
D O I
10.1016/0021-9517(90)90250-N
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
Kinetics of the rhodium-catalyzed reaction between carbon monoxide (CO) and nitrous oxide (N2O) were measured in a laboratory plug-flow reactor at temperatures between 550 and 700 K, space times between 0.06 and 0.26 s, and CO and N2O partial pressures between 0.6 and 7 Torr. A brief comparison was also made between the CON2O kinetics and kinetics of the CONO and COO2 reactions. The comparison showed that the CON2O reaction is an important subreaction of the CONO reaction (i.e., CO reacts initially with NO to produce N2O which undergoes further reaction is much lower than rates of the CONO and COO2 reactions (ratio of turnover frequencies at 475 K estimated as 1 (CON2O) vs 7.1 × 102 (CONO) vs 4.4 × 105 (COO2). CON2O rate measurements under differential conversion conditions at temperatures of 564 and 583 K yielded reaction orders of -1.0 ± 0.15 in CO pressure, 0.65 ± 0.1 in N2O pressure, and -0.30 ± 0.1 in total (CO + N2O) pressure. The reaction orders and apparent activation energy (40 ± 2 kcal/gmol) are consistent with a mechanism involving reaction between adsorbed CO and adsorbed N2O dissociation products. The low rate of the CON2O reaction compared to the COO2 and CONO reactions suggests that, under reaction conditions characterized by high CO coverages, the rate of dissociative N2O adsorption is slow compared to the rates of dissociative O2 or NO adsorption. © 1990.
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页码:422 / 431
页数:10
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