KINETIC STUDIES OF O(3P) ATOMS REACTIONS WITH PERHALOBUTENES IN THE RANGE OF 298 TO 363 K

COMETTO, PABLO M.; TACCONE, RAÚL A.; LANE, SILVIA I.

CHEMICAL PHYSICS LETTERS

Año: 2007 p. 245 - 250

0009-2614

The temperature dependences of the gas-phase reactions of O(3P) atoms with CF3CF=CFCF3, CF3CF=CClCF3 and CF3CCl=CClCF3 were studied under pseudo-first-order conditions in the range 298–359 K, using the discharge flow-chemiluminescence technique. The Arrhenius expressions obtained (in units of cm3 molecule-1 s-1) were: k1 = (0.32 ± 0.05) x 10-12 exp[-(8.1 ± 0.5) x 103/RT], k2 = (1.50 ± 0.74) x 10-11 exp[-(17.7 ± 1.4) x 103/RT] and k3 = (2.58 ± 1.10) x 10-11 exp[-(18.0 ± 1.2) x 103/RT], with Ea inJ mol-1. The positive temperature dependences point to the importance of the irreversibility of the addition channel. Complete substitutionby halogen atoms in the alkenes results in dramatic reduction of the rate constants. The reactivity trend with the ionization potential is also analyzed.