Homogeneous catalysis of the water gas shift reaction by iridium carbonyl in alkaline solution

摘要: Abstract The water gas shift reaction, H 2 O + CO ⇌ , catalyzed homogeneously by a system based on tetrairidiumdodecacarbonyl (Ir 4 (CO) 12 ) in alkaline 2-ethoxyethanol/water solution was examined at moderate temperatures (90–130°C) and pressures ( P 0.5–2.0 atm). catalytic reaction showed an approximate first-order dependence base concentration the of iridium. cycle shown to have zero order partial pressure CO. An apparent activation energy 10.7 kcal mol −1 obtained from linear Arrhenius plot hydrogen production over temperature range 90–130°C. predominant pathway can be explained mechanism which nucleophilic attack hydroxide metal hydride species HIr 11 − produces dihydride species, Ir 10 2− rate-limiting step. Subsequent this anion with gives plus again. complex 8 20 is catalytically poor component solution. has also been active toward decomposition formate. This however, concluded make insignificant contribution catalysis rate under conditions.