Ma. Fernandez et al., KINETICS OF THE WATER-GAS SHIFT REACTION CATALYZED BY CIS-[IR(CO)(2)(4-PIC)(2)]PF6 IN AQUEOUS 4-PICOLINE, Anales de quimica, 94(3), 1998, pp. 127-131
Described is a kinetics study of the homogeneous water gas shift react
ion catalyzed by the cis[Ir(CO)(2)(4-pic)(2)]PF6 complex in 4-picoline
aqueous solution. The activity proved to be nonlinear in iridium tota
l concentration, [Ir](tot), over the range 5 to 80 mM. This result was
interpreted in terms of the presence of active mononuclear and polynu
clear iridium species in the system, being the mononuclear the more ac
tive. The rate displays a first order dependence on CO pressure, P(CO)
, over the range 0.7 to 1.9 atm. The kinetics behavior with respect to
P(CO) leads to propose the CO addition to the catalytic species prior
to the rate-limiting step.