Rate coefficients for the reactions of OH radicals with monoethylene glycol monoalkyl ethers have been determined by the competitive method at 297 ± 3 K. Relative to the value k OH+hexanol = 12.5 × 10-12 cm3 molecule-1 s-1, the rate coefficients are as follows (in units of 10-12 cm3 molecule-1 s-1):  methoxyethanol, 10.8 ± 1.1; ethoxyethanol, 14.5 ± 0.4; propoxyethanol, 16.4 ± 0.7; butoxyethanol, 19.4 ± 2.0. In a second set of experiments relative rate coefficients were measured for the same series of glycol ethers (TST) against heptanol. In all cases the values of k TST/k heptanol divided by k TST/k hexanol yielded values of k heptanol/k hexanol consistent with our experimentally determined value of k heptanol/k hexanol = 1.24 ± 0.08. The results are discussed with respect to literature data and structure activity relationships, and the tropospheric lifetimes of the glycol ethers are estimated.

A gas-phase kinetics study of the atmospherically important reaction between Cl 2 and dimethyl sulfide (DMS) Cl 2 + CH 3 SCH 3 → products ----- (1) has been made using a flow-tube interfaced to a photoelectron spectrometer. The rate constant for this reaction has been measured at 1.6 and 3.0 torr at T= (294±2) K as (3.4 ± 0.7) x 10 -14 cm 3 molecule -1 s -1 . Reaction (1) has been found to proceed via an intermediate, (CH 3 ) 2 SCl 2 , to give CH 3 SCH 2 Cl and HCl as the products. The mechanism of this reaction and the structure of the intermediate were investigated using electronic structure calculations. A comparison of the mechanisms of the reactions between Cl atoms and DMS, and Cl 2 and DMS has been made and the relevance of the results to atmospheric chemistry is discussed.

The products formed by the hydroxyl radical-initiated oxidation of 2-ethoxyethanol (CH 3 CH 2 OCH 2 CH 2 OH) have been investigated by irradiating synthetic air mixtures containing the substrate, methyl nitrite, and nitric oxide at ppm levels in a Teflon bag reactor at room temperature. The decay of reactants and the formation of products were monitored by gas chromatography and mass spectrometry. The major products ethyl formate [HC(O)OCH 2 CH 3 ], ethylene glycol monoformate [HC(O)OCH 2 CH 2 OH], ethylene glycol monoacetate [CH 3 C(O)OCH 2 CH 2 OH], and ethoxyacetaldehyde [CH 3 CH 2 OCH 2 C(O)H] give a quantitative mass balance with the decay of the substrate molecule.The yields of these products were 34 ( 10%, 36 ( 7%, 7.8 ( 2.4%, and 24 ( 13%, respectively, in terms of percent of 2-ethoxyethanol removed by the OH radical. The product distribution is explained by a mechanism involving initial OH attack at the three CH 2 groups in 2-ethoxyethanol followed by the subsequent reactions of the resulting alkyl and alkoxy radicals. The decomposition reactions of the alkoxy radicals from 2-ethoxyethanol, which can take place either by C-C or C-O bond breaking, involve preferential C-C cleavage rather than C-O cleavage. Rate coefficients at room temperature for the reactions of OH radicals with ethoxyacetaldehyde and 2-methyl-1,3-dioxolane (CH 3 CHOCH 2 CH 2 O, a minor product) have been determined to be 16.6 × 10 -12 and 9.4 × 10 -12 cm 3 molecule -1 s -1 , respectively.