We measured the rate constant for reactions of the OH radical with several potential chlorofluorocarbon replacements over the temperature range 251--314 K using laser photolysis laser-induced fluorescence techniques. The compounds studied and Arrhenius parameters determined from fits to the measured rate constants are as follows: CHF2OCHF2(E 134), k(T)=(5.4¿3.5)¿10-13 cm3 s-1 exp<(-3.1¿0.4 kcal mol-1)/RT>; CF3CH2CF3(FC 236fa), k(T)=(2.0¿1.0¿10-14 cm3 s-1 exp<(-1.8¿0.3 kcal mol-1)/RT>; CF3CHFCHF2(FC 236ea), k(T)=(2.0¿0.9)¿10-13 cm3 s-1 exp<(-2.0¿0.3 kcal mol-1)/RT>; and CF3CF2CH2F(FC 236cb), k(T)=(2.6¿1.6)¿10-13 cm3 s-1 exp<(-2.2¿0.4 kcal mol-1)/RT>. The measured activation energies (2--3 kcal mol-1) are consistent with a mechanism of H atom abstraction. The tropospheric lifetimes, estimated from the measured OH reaction rates, and measured integrated infrared absorption cross sections over the range 770 to 1430 cm-1 suggest that E 134 and FC 236fa may have significant global warming potential, while FC 236ea and FC 236cb do not. ¿ American Geophysical Union 1993