Hydrogen abstraction reactions by atomic fluorine. IV. Temperature dependence of the intermolecular kinetic isotope effect for the nonthermal 18F+H2 reaction J. Chem. Phys. 64, 417 (1976); 10.1063/1.431936Hydrogen abstraction reactions by atomic fluorine. III. Temperature dependence of the intermolecular kinetic isotope effect for the thermal F+H2 reactionWe have measured the rate constant for the reaction of BO with H2 between 690 and 1030 K. The results are compared to transition-state-theory calculations consistent with a revised value for the heat of formation of the product HBO. By scaling the frequency of the doubly degenerate bend of the HHBO transition state in analogy with the isoelectronic HHCN transition state and lowering the calculated barrier from 9.5 to 8.5 kcal/mol, we are able to bring the theoretical and experimental rate constants into excellent agreement. Over the temperature range 300-3000 K, the theoretical rate constant is well represented by k(T) = 7.49 X 10-23 cm 3 S-I T 3 . 53 exp( -1590/T).

Articles you may be interested inReactions of pulsed laser produced boron and nitrogen atoms in a condensing argon stream J. Chem. Phys. 98, 922 (1993); 10.1063/1.464256 Laser fluorescence study of ytterbium plus halomethane reactions J. Chem. Phys. 73, 3831 (1980); 10.1063/1.440614 Calculation of Raman scattering parameters for methane and halomethanes from an atom dipole interaction model J. Chem. Phys. 66, 3455 (1977); 10.1063/1.434431Chemiluminescence from the gas phase reaction of atomic boron with the alkali metal fluorides Rate constants have been measured for the reactions of boron atoms with a series of halomethanes. The experiments were performed in a linear flow tube apparatus at 300 K. The measured rate constants in units ofcm 3 molecule-I S-I are CCI 4 :9.. The reaction of boron with all the chloromethanes is facile. The chlorofluoromethanes present a more complex pattern. Noteworthy is the low reactivity of the channel to produce BF, furthermore, the presence of fluorine in the halomethanes reduces the reactivity at the chlorine site. Semiempirical MNDO calculations were performed on the reacting systems. These calculations suggest possible explanations for the observed results.

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