A smog chamber for studies of the reactions of terpenes and alkanes with ozone and OH

Abstract

The design and performance of a smog chamber for the study of photochemical reactions under simulated environmental conditions is described. The chamber is thermostated for aerosol experiments, and it comprises a gas chromatographic sample enrichment system suitable for monitoring hydrocarbons at the ppbv level. By irradiating NO x/alkane-mixtures rate constants for the reaction of OH radicals with n-alkanes are determined from n-pentane to n-hexadecane to be (k++_2a)/lO -12 cm 3 at 312K. Rate constants, (k _+ 2a)/10 -17 cm 3 s -l , for the reaction of ozone with trans-2-butene (21.2 _+ 1.0), cis-3-methylpentene-(2) (47.2 _+ 1.7), cyclopentene (62.4_+3.5), cyclohexene (7.8 _+0.5), cycloheptene (28.3 _+ 1.5), c~-pinene (8.6 _+ 1.3), and fl-pinene (1.4 _+ 0.2) are determined in the dark at 297 K using cis-2-bntene (13.0) as reference standard.

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

“…15). The rate constant obtained relative to n-heptane by Nolting et al (1988) at 312 K is in excellent agreement with the recommendation.…”

“…The room temperature rate constants for n-nonane are all from relative rate studies (Atkinson et al, 1982b;Behnke et al, 1987Behnke et al, , 1988Nolting et al, 1988;Ferrari et al, 1996;Kramp and Paulson, 1998), and are in good agreement. A least-squares analysis of the rate constants of Atkinson et al (1982b), Behnke et al (1987Behnke et al ( , 1988, Nolting et al (1988), Koffend andCohen (1996), Ferrari et al (1996) and Kramp and Paulson (1998), using the expression k=AT 2 e −B/T , leads to the recommendation of…”

“…As shown in Table 42, the available room temperature rate constants for n-decane are all from relative rate studies (Atkinson et al, 1982b;Nolting et al, 1988;Behnke et al, 1988;Aschmann et al, 2001), and are in good agreement.…”

“…Chem. Phys., 3, 2233 -2307, 2003 www.atmos-chem-phys.org/acp/3/2233 / ( Atkinson et al, 1982b;Behnke et al, 1987;Nolting et al, 1988) having been carried out. Figure 15 shows an Arrhenius plot of the absolute rate constants of Greiner (1970) and Koffend and Cohen (1996) together with the relative rate data of Atkinson et al (1982b), Behnke et al (1987) and .…”

“…Figure 15 shows an Arrhenius plot of the absolute rate constants of Greiner (1970) and Koffend and Cohen (1996) together with the relative rate data of Atkinson et al (1982b), Behnke et al (1987) and . The three relative rate measurements (Atkinson et al, 1982b;Behnke et al, 1987;Nolting et al, 1988) are in excellent agreement, and a least-squares analysis of the rate constants from the studies of Atkinson et al (1982b), Behnke et al (1987) and Koffend and Cohen (1996) (the study of Nolting et al (1988) was not used in the evaluation because the n-octane rate constant is used to derive the n-heptane rate constant which was the reference compound in the Nolting et al, 1988 study), using the expression k=AT 2 e −B/T , leads to the recommendation of k(n−octane)=2.72×10 −17 T 2 e 361/T cm 3 molecule −1 s −1 over the temperature range 290-1080 K, and…”