The H abstraction reaction mechanisms between sevoflurane and Cl atom were investigated with DFT method. The geometries of all the species were optimized at wB97XD/6-311++G(d,p) level. Thermochemistry properties were calculated with the accurate model chemistry method G3MP2 combined with the standard statistical thermodynamics. Gibbs free energies were used for analyzing reaction pathways. Three pathways correspond to the H9, H11 and H10 reactions with the barriers of 55.01, 32.50 and 32.50 kJ.mol(-1), respectively. The rate constants for all the pathways over a wide temperature range of 200-2000 K were calculated, and the result is in good agreement with the experimental values. (C) 2014 Elsevier B.V. All rights reserved.