Kinetic study of OH radical reaction with n‐heptane and n‐hexane at 240–340K using the relative rate/discharge flow/mass spectrometry (RR/DF/MS) technique

Abstract

The kinetics of reactions of OH radical with n-heptane and n-hexane over a temperature range of 240-340K has been investigated using the relative rate combined with discharge flow/mass spectrometry (RR/DF/MS) technique. The rate constant for the reaction of OH radical with n-heptane was measured with both n-octane and n-nonane as references. At 298K, these rate constants were determined to be k 1,octane = (6.68 ± 0.48) × 10 −12 cm 3 molecule −1 s −1 and k 1,nonane = (6.64 ± 1.36) × 10 −12 cm 3 molecule −1 s −1 , respectively, which are in very good agreement with the literature values. The rate constant for reaction of n-hexane with the OH

Rate Constants for the Reaction of OH Radicals with Hydrocarbons in a Smog Chamber at Low Atmospheric Temperatures

“…More experimental data are needed (especially at high temperatures) to determine a more appropriate temperature dependence relationship from the existing Arrhenius expressions. Data reported by Crawford et al [29] for n-hexane are away from expression 3 and in case of n-heptane, their data are also lower than the recommended Arrhenius expression, indicating a systematic deviation. When using only n-hexane as reference compound, our result at 248K for n-heptane agrees to the results of Crawford et al and Wilson et al (see SI, Figure S6).…”

Kinetics Study of the Reaction of OH Radicals with C5–C8Cycloalkanes at 240–340 K using the Relative Rate/Discharge Flow/Mass Spectrometry Technique

“…It is critical to choose appropriate reference compounds in a kinetics study using the relative rate technique because usage of different reference rate constants can affect the target rate constant. In this study, we used n -hexane, n -heptane, n -octane, and n -nonane as reference compounds to measure rate constants for the reaction of C 5 –C 8 cycloalkanes at 240 – 340 K. The rate constants for these reference compounds are available from our previous investigations , and from several other groups. ,, We chose to use the rate constants provided by our group in the present kinetics study of reactions – at 240 – 340 K for two reasons. First, these rate constants were previously determined as independent kinetics studies by our group, and within experimental uncertainty, they are consistent with other research groups at room temperature.…”

“… a The rate constant of the hydroxyl radical reaction with n -hexane were taken from ref , and that of cyclohexane is taken from Table of this work. b The error bar was taken as 2σ. The number in parentheses represents the number of data points collected at corresponding temperature. c RR: relative rate; DF: dischage flow; MS: mass spectrometry. …”

“… a The rate constant of the hydroxyl radical reaction with n -hexane were taken from ref , and that of cyclohexane is taken from Table of this work. …”

Kinetics Study of the Reactions of OH with n-Undecane and n-Dodecane Using the RR/DF/MS Technique

“…The RR/DF/MS technique for kinetics investigation of the reactions of VOCs with OH radicals was developed in our laboratory, and the technique has been used to determine the rate constant of OH reaction with n -C 6 - n -C 10 alkanes as a function of temperature. − Figure shows the schematic of the RR/DF/MS apparatus used to study the kinetics of reactions and . Briefly the flow reactor was made of a 100 cm Pyrex tube with an internal diameter of 5.08 cm.…”