Rate coefficient for the reaction FCO+FC(O)O2-->2 FC(O)O at 296 K.

BADENES, M. P.; CASTELLANO, E.; COBOS, C. J.; CROCE, A. E.; MARIA EUGENIA TUCCERI

CHEMICAL PHYSICS LETTERS

Año: 1999 vol. 303 p. 482 - 488

0009-2614

   The kinetics of the reaction FCO+FC(O)O2 --> 2 FC(O)O has been studied. The reactants were generated by KrF excimer laser flash photolysis of mixtures of (FCO)2 and O2 in excess of M=SF6 at 296 K. The three radicals were monitored by absorption spectroscopy. Assuming that the reaction proceeds through a complex-forming process, the measured rate coefficient,  (2.1±0.5)x10-11 cm3 molecule-1 s-1, agrees very well with that predicted by a simplified version of the statistical adiabatic channel model using a ratio a/b=0.50 between the looseness and the Morse parameters. The rate coefficient of (3.7±0.2)x10-12 cm3 molecule-1 s-1 was determined for the FC(O)O+FC(O)O2+M-->(FCO)2O3+M reaction. Employing isodesmic reaction schemes at the B3LYP/6-311++G(d,p) level of theory, the enthalpy of formation of FC(O)O2 and (FCO)2O2 are calculated to be -76.1±4 and -202.9±4 kcal mol-1 respectively.