Pyrolysis Kinetics of 2-Bromobutane and 2-Bromopentane in the Gas Phase

Article abstract of DOI:10.1021/j100338a044

The kinetics of the gas-phase pyrolysis of 2-bromobutane and 2-bromopentane were determined in a static system over the temperature range of 310-360 deg C and the pressure range of 40-180 Torr.The reactions in seasoned vessels, and in the presence of a free-radical inhibitor, are homogeneous, are unimolecular, and follow a first-order rate law.The temperature dependence of the rate coefficients is given by the following Arrhenius equations: for 2-bromobutane, log k₁(s^-1) = (13.04+/-0.05)-(188.3+/-0.6) kJmol^-1 (2,303RT)^-1; for 2-bromopentane, log k₁(s^-1) = (13.08+/-0.23)-(187.0+/-2.7)kJmol^-1 (2.303RT)^-1.The olefin products appear to rapidly isomerize in the presence of HBr gas until an equilibrium is reached.The elimination kinetics of these compounds suggest that the effect of the alkyl groups R in RCHBrCH3 is polar (+I electron release).