Reaction of CF₃ radicals with H₂O and D₂O

Abstract

The reaction of CF3 radicals with Ha0 (D20) has been studied over the range of 533-723 K using the photolysis and the pyrolysis of CFJ as the free radical source. Arrhenius pa- where klkE/* is in ~r n~'~/ r n o l~'~-s~~~ and B = 2.303RT/cal/mol. The activation energy and the primary kinetic isotope effect have been compared with those derived from the BEBO method.

Reflected Shock Tube and Theoretical Studies of High-Temperature Rate Constants for OH + CF3H ⇆ CF3 + H2O and CF3 + OH → Products

“…There are three pertinent earlier theoretical investigations on reactions 1 and -1 [19][20][21] of varying degrees of complexity. Pasteris et al 19 used the bond energy-bond order (BEBO) method to estimate barrier heights, force fields, and configurations to calculate rate constant values for k -1 . Their results on transformation to k 1 give predictions that are high by ∼10.…”

“…As a supplement to these experimental studies, we have also performed ab initio based variational transition state theory (TST) studies of the CF 3 H + OH and CF 3 + OH reactions. The former reaction has been the subject of a few prior theoretical kinetics studies. − The present work proceeds beyond these studies by (i) implementing higher level quantum chemical estimates, (ii) considering the effects of anharmonicities on the transition state partition functions, (iii) including variational treatments, and (iv) considering tunneling through the vibrationally adiabatic ground state potential.…”

Arrhenius parameters for the hydrogen abstraction from ammonia by CF3 radicals

“…Even if 5 kJ/mol were taken for E, [91, the EH value would be reduced in 2.5 kJ/mol, which is within the experimental error. Under enthalpy considerations we did expect this EH value since for the reaction with CH,CN, which is exothermic in about 54 kJ/mol, a n activation energy of 49.4 kJ/mol has been found [21, whereas for a very endothermic reaction such as CF, + H 2 0 a value of 70.2 kJ/mol has been reported [15].…”

The gas phase reaction of CF3 radicals with C6F5H in the temperature range 373–658 K

“…The Arrhenius parameters for hydrogen abstraction by CF3 radicals have been reported for many compounds of different nature such as alkanes, alcohols, aldehydes, ketones, amines, etc [l]. In most of the cases these are exothermic or thermoneutral reactions except for a few such as benzene which was studied by Whittle et al and for HCN, DCN [2,3], and H20, D 2 0 [4], reactions previously studied in our laboratory.…”

“…In most of the cases these are exothermic or thermoneutral reactions except for a few such as benzene which was studied by Whittle et al and for HCN, DCN [2,3], and H20, D 2 0 [4], reactions previously studied in our laboratory.…”