Kinetics of the reactions of O₃ and OH radicals with furan and thiophene at 298 ± 2 K

Abstract

Rate constants for the reactions of 0 3 and OH radicals with furan and thiophene have been determined at 298 f 2 K. The rate constants obtained for the 0 3 reactions were (2.42 f 0.28) X 1O-lS cm3/molec.s for furan and <6 X cm3/molec-s for thiophene. The rate constants for the OH radical reactions, relative to a rate constant for the reaction of OH radicals with n-hexane of (5.70 f 0.09) X cm3/molec.s, were determined to be (4.01 f 0.30) X lo-" cm3/molec.s for furan and (9.58 f 0.38) X 10-l2 cm3/molec.s for thiophene. There are to date no reported rate constant data for the reactions of OH radicals with furan and thiophene or for the reaction of 0 3 with furan. The data are compared and discussed with respect to those for other alkenes, dialkenes, and heteroatom containing organics.

Kinetics of the gas-phase reactions of OH radicals with alkanes and cycloalkanes

“…In the temperature range 292-390 K the agreement between the absolute and relative rate studies is good. The room temperature relative rate data of Atkinson et al (1983a), , Behnke et al (1987Behnke et al ( , 1988 and McLoughlin et al (1993), which are not shown in the Arrhenius plot in Fig. 11, are also in good agreement with these data of Atkinson et al (1982a), Klein et al (1984), Donahue et al (1998) and DeMore and Bayes (1999).…”

Effects of ring strain on gas‐phase rate constants. 2. OH radical reactions with cycloalkenes

“…The experimental technique has been described previously [7,9] and was essentially identical to that used for the determination of OH radical rate constants for a series of acyclic alkenes [9]. Hence only the relevant details are given here.…”

“…(1) OH + alkene -products (2) OH + isoprene -products Provided these organics are consumed only by reaction with OH radicals (see later) and since dilution due to sampling is avoided by use of a collapsible Teflon reaction bag, then [7,9] Irradiations were carried out in a -60-L cylindrical Teflon reaction bag surrounded by 24 GE F15T8-BL 15-W blacklights. In this work eight of these blacklights were used, corresponding to a photolytic half-life of CH3ONO of -30 min.…”

“…A recent study of the reactions of OH radicals with a series of cyclic and polycyclic alkanes, where the reactions proceed via H-atom abstraction, showed [7] that ring strain energies in excess of -5 kcal mol-I lead to a decrease in the rate constants relative to those expected for the strain-free molecules. In contrast, the room temperature rate constants for the addition reactions of 0 3 with a series of cycloalkenes appear to correlate with the difference in ring strain energy between the cycloalkene and the corresponding cycloalkene or cycloalkane with one less double bond [8], with, for example, the rate constant for bicyclo[2.2.1]-2-heptene being a factor of -16 higher than that for cis-2-butene (which has the same number and configuration of substituents).…”

Effects of ring strain on gas‐phase rate constants. I. Ozone reactions with cycloalkenes

“…In a recent study of the reactions of OH radicals with a series of cyclic and polycyclic alkanes, where the reactions proceed via H-atom abstraction, it was observed [9] that ring strain energies in excess of -5 kcal/mol led to a decrease in the rate constants relative to those expected for the strainfree molecules. For the addition reactions of 0 3 and OH radicals, however, data are available only for a small number of cycloalkenes [7,8].…”