Rate constants of the reactions of OH radicals with cyclopropane and cyclobutane

Abstract

The kinetics of the reactions of hydroxy radicals with cyclopropane and cyclobutane has been investigated in the temperature range of 298-492 K with laser flash photolysidresonance fluorescence technique. The temperature dependence of the rate constants is given by k l = (1.17 ? 0.15) x T3'' exp[-(1037 * 87) kcal mol-'/RT] cm3 molecule-' s' and kz = (5.06 ? 0.57) x T3"exp[-(228 * 78) kcal mol-'/RT] cm3 molecule-' s-' for the reactions OH + cyclopropane + products (1) and OH + cyclobutane + products (2), respectively. Kinetic data available for OH + cycloalkane reactions were analyzed in terms of structure-reactivity correlations involving kinetic and energetic parameters.

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

“…Figure 18 shows an Arrhenius plot of the data from these studies (for the study of Wilson et al (2001) only the data obtained relative to the rate constant for ethane are plotted). The absolute rate constants of Dóbé et al (1991Dóbé et al ( , 1992 are significantly higher than the other data, more so at room temperature, with the discrepancy decreasing as the temperature increases (Fig. 18).…”

“…Over the temperature range ∼200-800 K the absolute rate constants of Overend et al (1975), Howard and Evenson (1976b), Leu (1979), Lee and Tang (1982), Margitan and Watson (1982), Tully et al (1983Tully et al ( , 1986a, Smith et al (1984), Devolder et al (1984), Schmidt et al (1985), Baulch et al (1985), Stachnik et al (1986), Bourmada et al (1987), Wallington et al (1987), Lafage et al (1987), Zabarnick et al (1988), Abbatt et al (1990), Schiffman et al (1991, Dóbé et al (1991Dóbé et al ( , 1992, Sharkey and Smith (1993), Talukdar et al (1994), Crowley et al (1996), Donahue et al (1996Donahue et al ( , 1998 and Clarke et al (1998) are in good agreement. Because several of these studies involved measurement of the rate constant for the reaction of OH radicals with ethane at one temperature (generally room temperature) as a check on the experimental technique used (Leu, 1979;Lee and Tang, 1982;Margitan and Watson, 1982;Devolder et al, 1984;Bourmada et al, 1987;Lafage et al, 1987;Zabarnick et al, 1988;Dóbé et al, 1991Dóbé et al, , 1992, the rate constants from the more extensive absolute studies of Tully et al (1983Tully et al ( , 1986a, S...…”

“…Rate constants are available from the absolute rate studies of Jolly et al (1985), Dóbé et al (1991Dóbé et al ( , 1992 and Clarke et al (1998) and from the relative rate studies of DeMore and Bayes (1999) and Wilson et al (2001). Figure 18 shows an Arrhenius plot of the data from these studies (for the study of Wilson et al (2001) only the data obtained relative to the rate constant for ethane are plotted).…”

“…Accordingly, the data of Dóbé et al (1991Dóbé et al ( , 1992 are not used in the evaluation of the rate constant for this reaction. While this discrepancy could be due to the presence of reactive impurities in the cyclopropane sample used by Dóbé et al (1991Dóbé et al ( , 1992, Dóbé et al (1991Dóbé et al ( , 1992 stated that the cyclopropane sample was ≥99.99% pure with 0.01% propene impurity (Dóbé et al, 1992) (which would result in a ∼4% increase in the measured rate constant at 298 K). The room temperature rate constants of Jolly et al (1985), Clarke et al (1998), DeMore and Bayes (1999) and Wilson et al (2001) are in good agreement.…”

“…As shown in Table 52, rate constants are available from the absolute rate studies of Dóbé et al (1991Dóbé et al ( , 1992 and from Atmos. Chem.…”