The reactions of Cl with tetrahydrofuran, tetrahydropyran, and dimethyl ether have been studied as a function of temperature, pressure, and O 2 concentration. The temperature was varied from approximately 280 to 360 K, the mole fraction of O2 ranged from zero to approximately 0.6, and the experiments were made in a bath of argon at total pressures ranging from approximately 300 to 760 Torr. The rate coefficients were measured using the relative rate method with gas chromatographic analysis. The reaction of Cl with isobutane was the reference reaction, the rate coefficients for which were calibrated against the reaction of propane with chlorine atoms as a function of temperature. The rate coefficients were unaffected by the concentration of O2 or by variation in pressure. The rate coefficient for the reaction of Cl with isobutane increased slightly with decreasing temperature. This weak temperature dependence of the rate coefficient was in satisfactory agreement with information in the literature and is represented in Arrhenius form by k(T) = (1.02-0.25+0.32)× 10-10 exp(99 ± 88/T) cm3 molecule-1 s-1, where the uncertainties represent two standard deviations. The rate coefficients for the reactions of Cl with the ethers did not show a statistically significant dependence on temperature. Their average values over our range of temperature are: for Cl + tetrahydrofuran, k = (2.71 ± 0.34)× 10-10 cm3 molecule-1 s-1; for Cl + tetrahydropyran, k = (2.03 ± 0.82)× 10-10 cm3 molecule -1 s-1; and for Cl + dimethyl ether, k = (1.73 ± 0.22)× 10-10 cm3 molecule-1 s -1, in which the uncertainties are again two standard deviations.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry