The reaction of C6H5 with CO: Kinetic measurement and theoretical correlation with the reverse process

The kinetics of the C6H5 reaction with CO has been studied by the cavity ri ng-down spectrometric technique in the temperature range 295-500 K at 12-12 0 Torr pressure with Ar as the carrier gas. The reaction occurred near the high-pressure limit under the conditions used. A weighted least-squares ana lysis of all data gives the rate constant for the association reaction, k(1 ) = 10(11.93+/-0.14) exp[-(1507 +/- 109)/T] cm(3) mole(-1) s(-1), where the errors represent two standard deviations. Our result can correlated satisf actorily with the kinetic data reported by Solly and Benson for the reverse process (J. Am. Chem. Sec. 1971, 93, 2171) with the Rice-Ramsperger-Kassel -Marcus (RRKM) theory using the transition-state parameters computed quantu m mechanically by the MP2 method with the 6-31G(d,p) basis set. Combination of the forward and reverse reaction data gives Delta H-1(0) = -24.6 +/- 0. 8 kcal/mol at 0 K and k(1)(infinity) = 5.3 x 10(14) exp(-14600/T) s(-1) for the temperature range 300-670 K, The heat of reaction, combining with the known heats of formation of the reactants, leads to Delta(f)H(0)(o) (C6H5CO )= 32.5 +/- 1.5 kcal/mol.