ROOM-TEMPERATURE RATE COEFFICIENTS FOR THE REACTIONS OF OH RADICALS WITH SOME MONOETHYLENE GLYCOL MONOALKYL ETHERS

Rate coefficients for the reactions of OH radicals with monoethylene g lycol monoalkyl ethers have been determined by the competitive method at 297 +/- 3 K. Relative to the value k(OH+hexanol) = 12.5 x 10(-12) c m(3) molecule(-1) s(-1), the rate coefficients are as follows (in unit s of 10(-12) cm(3) molecule(-1) s(-1)): methoxyethanol, 10.8 +/- 1.1; ethoxyethanol, 14.5 +/- 0.4; propoxyethanol, 16.4 +/- 0.7; butoxyethan ol, 19.4 +/- 2.0. In a second set of experiments relative rate coeffic ients 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 wi th our experimentally determined value of k(heptanol)/k(hexanol) = 1.2 4 +/- 0.08. The results are discussed with respect to literature data and structure activity relationships, and the tropospheric lifetimes o f the glycol ethers are estimated.