Temperature-dependent rate constants for the gas-phase reactions of OH radicals with 1,3,5-trimethylbenzene, triethyl phosphate, and a series of alkylphosphonates.

Rate constants for the reactions of OH radicals with dimethyl methylphosphonate [DMMP, (CH3O)2P(O)CH3], dimethyl ethylphosphonate [DMEP, (CH3O)2P(O)C2H5], diethyl methylphosphonate [DEMP, (C2H5O)2P(O)CH3], diethyl ethylphosphonate [DEEP, (C2H5O)2P(O)C2H5], triethyl phosphate [TEP, (C2H5O)3PO] and 1,3,5-trimethylbenzene have been measured over the temperature range 278-348 K at atmospheric pressure of air using a relative rate method. alpha-Pinene (for DEMP, DEEP, TEP and 1,3,5-trimethylbenzene) and di-n-butyl ether (for DMMP and DMEP) were used as the reference compounds, and rate constants for the reaction of OH radicals with di-n-butyl ether were also measured over the same temperature range using alpha-pinene and n-decane as the reference compounds. The Arrhenius expressions obtained for these OH radical reactions (in cm3 molecule(-1) s(-1) units) are 8.00 x 10(-14)e(1470+/-132)/T for DMMP (296-348 K), 9.76 x 10(-14)e(1520+/-14)/T for DMEP (296-348 K), 4.20 x 10(-13)e(1456+/-227)/T for DEMP (296-348 K), 6.46 x 10(-13)e(1339+/-376)/T for DEEP (296-348 K), 4.29 x 10(-13)e(1428+/-219)/T for TEP (296-347 K), and 4.40 x 10(-12)e(738+/-176)/T for 1,3,5-trimethylbenzene (278-347 K), where the indicated errors are two least-squares standard deviations and do not include the uncertainties in the rate constants for the reference compounds. The measured rate constants for di-n-butyl ether are in good agreement with literature data over the temperature range studied (278-348 K).