The reactions of CFCl3, CF2Cl2, and N2O with OH are studied at temperatures up to 480 K in a discharge-flow system with resonance fluorescence detection of OH. Little, if any reaction is found, upper limits of 5,6 and 4¿10-6 cm3 s-1 are reported at 480 K for the three rate constants. The results are compared with other investigations and with reaction rate theory. On the basis of a very simple model, removal times greater than 104 years are calculated for reaction with tropospheric OH, i.e. they are negligibly slow removal processes.