Kinetic studies of OH-initiated reactions of isoprene uri icon

abstract

  • We report laboratory kinetic studies of isoprene reactions initiated by the hydroxyl radical OH, using a turbulent flow reactor coupled to chemical ionization mass spectrometry (CIMS) detection. The rate constants for the reaction of isoprene with OH have been measured in the pressure range of 70 to 120 torr at 2982 K and are found to be independent of pressure with an averaged value of (10.10.8)1011 cm3 molecule1 s1. The error limit given is within 1 standard deviation; a systematic error is estimated to be 15%. We also describe direct observation of the OHisoprene adduct based on ionmolecule reactions by using the CIMS method. The formation of the OHisoprene adduct was used to extract the rate constant between OH and isoprene; within the uncertainty of the experiments the results were consistent with those obtained from the observed disappearance of OH. By monitoring the formation of the OHisoprene adduct in the presence of oxygen molecules, an overall rate constant between OHisoprene adduct and O2 has been first determined, with an averaged value of (2.80.7)1015 cm3 molecule1 s1 at 76 torr and an estimated systematic error of 50%. Atmospheric implications of the present results to the photochemical oxidation of isoprene are discussed.

published proceedings

  • JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES

author list (cited authors)

  • Zhang, R. Y., Suh, I., Lei, W., Clinkenbeard, A. D., & North, S. W.

complete list of authors

  • Zhang, RY||Suh, I||Lei, W||Clinkenbeard, AD||North, SW