Rate Coefficient Measurements and Theoretical Analysis of the OH + (E)‑CF₃CH==CHCF₃ Reaction

Rate coefficients, k, for the gas-phase reaction of the OH radical with (E)CF3CHCHCF3 ((E)-1,1,1,4,4,4-hexafluoro-2-butene, HFO-1336mzz(E)) were measured over a range of temperatures (211−374 K) and bath gas pressures (20−300 Torr; He, N2) using a pulsed laser photolysis−laser-induced fluorescence (PLP−LIF) technique. k1(T) was independent of pressure over this range of conditions with k1(296 K) = (1.31 ± 0.15) × 10−13 cm3 molecule−1 s−1 and k1(T) = (6.94 ± 0.80) × 10−13exp[−(496 ± 10)/T] cm 3 molecule−1 s−1, where the uncertainties are 2σ, and the pre-exponential term includes estimated systematic error. Rate coefficients for the OD reaction were also determined over a range of temperatures (262−374 K) at 100 Torr (He). The OD rate coefficients were ∼15% greater than the OH values and showed similar temperature dependent behavior with k2(T) = (7.52 ± 0.44) × 10−13exp[−(476 ± 20)/T] and k2(296 K) = (1.53 ± 0.15) × 10−13 cm3 molecule−1 s−1. The rate coefficients for reaction 1 were also measured using a relative rate technique between 296 and 375 K with k1(296 K) measured to be (1.22 ± 0.1) × 10−13 cm3 molecule−1 s−1, in agreement with the PLP−LIF results. In addition, the 296 K rate coefficient for the O3 +( E)CF3CHCHCF3 reaction was determined to be