Rate Constants and Kinetic Isotope Effects in the Reactions of Atomic Chlorine withn-Butane and Simple Alkenes at Room Temperature

Abstract

Rate constants for the reactions of chlorine atoms with n-butane and simple alkenes, as well as most of their deuterated analogs, were studied at room temperature using two independent techniques. Using a fast flow discharge system (FFDS), the decay of chlorine atoms in 1 Torr He was followed using resonance fluorescence at 135 nm. In relative rate (RR) studies the decay of the organic was followed, relative to a reference compound, using GC-FID when they both reacted with chlorine atoms. These RR measurements were performed at 1 Torr in N2 and at 1 atm in both N2 and air. The results of the FFDS and RR studies at 1 Torr were generally in excellent agreement with each other and, where available, with literature data. Discrepancies appear to exist at 1 atm for isoprene, where the addition portion of the rate constant measured in this laboratory is 40% higher than a value for k∞ reported recently by Bedjanian et al.40 Our rate constant for 1,3-butadiene is 25% smaller than that of Bierbach et al.39 Rate con...