Solubility and hydrolysis of HCFC‐22 (CHF2Cl): Upward revision of rate constants for aqueous reactions of CHF2Cl with OH− at elevated temperature

Abstract

AbstractHenry's law constants of CHF2Cl in water at temperature T in K, KH(T) in M atm−1, were determined to be ln(KH(T))=−(11.1±1.5)+((2290±500)/T) at 313–363 K by means of a phase ratio variation headspace method. The temperature‐dependent rate constants for aqueous reactions of CHF2Cl with OH−, k(T) in M−1 s−1, were also determined to be 3.7×1013exp(−(11, 200/T)) at 313–353 K, by considering the gas–water equilibrium, the aqueous reaction at room temperature, and liquid‐phase diffusion control. The liquid‐phase diffusion control was approximated with a one‐dimensional diffusion first‐order irreversible chemical reaction model. The k(T) value we determined is 10 times (at 353 K) or 3 times (at 313 K) as large as the value reported (R. C. Downing, Fluorocarbon Refrigerants Handbook, Prentice Hall: Englewood Cliffs, NJ, 1988). This upward revision of k(T) indicates that the removal efficiency of CHF2Cl directly through the hydrolysis (CHF2Cl + OH−) is higher than previously expected at temperatures, such as 353 K, relevant to wet flue gas cleaning systems for ozone‐destruction substance‐destruction facilities. © 2011 Wiley Periodicals, Inc. Int J Chem Kinet 43: 639–647, 2011