The rate constants, for the hydrogen abstraction reaction of hydrofluoroethers (HFEs) and hydrofluorocarbons (HFCs) with OH radicals (k(OH)) at 298 K were estimated by using new empirical estimation method consisting of two steps. Firstly we calculated the bond dissociation enthalpies (BDEs) of the C-H bond by using the artificial neural network (ANN) technique from molecular formula. Next, k(OH) were evaluated by using the estimated BDEs and a modified Heicklen's empirical equation. Consequently, the combination of these two empirical methods could estimate the k(OH) of HFEs and HFCs within the 0.56-1.8 times of experimental data as average deviation. (C) 2002 Elsevier Science B.V. All rights reserved.