The rate of approach to equilibrium in uncatalyzed CO2 hydration reactions: The theoretical effect of buffering capacity

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Abstract

A treatment of the kinetics of the uncatalyzed reaction of CO2 and H2O is presented with particular reference to the rate of equilibration in an open system at constant PCO2 under conditions of different buffering capacities, d[HCO3]/dpH. The treatment is based on the accepted first-order kinetics of the hydration and dehydration reactions and characterizes the strong dependence of the time course of the equilibration process on the buffering capacity. The computed half-times are found to vary from 0.3 to 30 sec as the buffering capacity increases from 0.2 mM/pH unit (a solution devoid of non-bicarbonate buffer) to 40 mM/pH unit. An appendix is included which describes the computation method.

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Work supported by grant HE 02888-12 of the National Heart Institute, National Institutes of Health.

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Supported by Medical Scientist Program of the Life Insurance Medical Research Fund.

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