The detailed kinetic mechanism of the CH2OO + C2F4 reaction was explored using the accurate composite G4 method and the master equation/Rice-Ramsperger-Kassel-Marcus (ME/RRKM) rate model. Corrections for tunneling, hindered internal rotation and anharmonicity treatments were included. The 1,3-cycloaddition was found to be the rate-determining step with a small barrier Delta V-double dagger (0 K) of 3.5 kcal/mol. The total rate constants were suggested as k(tot)(T) = 3.69 x 10(23) x T-2.91 x exp(-1114 K/T) (cm(3)/molecule/s) for T = 200-1000 K & P-independence (P = 76-760 torr). (C) 2018 Elsevier B. V. All rights reserved.