RATES OF REACTION BETWEEN THE NITRATE RADICAL AND SOME ALIPHATIC-ALCOHOLS

Rate coefficients for the gas-phase reaction of NO3 with methanol, eth anol and propan-2-ol have been determined. Absolute rates were measure d at temperatures between 258 and 367 K using the fast flow-discharge technique. The measured rate coefficients (in units of 10(-15) cm(3) m olecule(-1) s(-1)) at 295 K are: 0.132 +/- 0.024, 1.37 +/- 0.10 and 3. 13 +/- 0.64 for methanol, ethanol and propan-2-ol, respectively. The t emperature dependence of the rate coefficients can be expressed as Arr henius equations: k(methanol) = (1.06 +/- 0.51) x 10(-12) exp[-(2093 /- 803)/T], k(ethanol) = (6.99 +/- 1.21) x 10(-13) exp[-(1815 +/- 419) /T] and k(propan-2-ol) = (1.54 +/- 0.75) x 10(-12) exp[-(1743 +/- 1009 )/T] (in units cm(3) molecule(-1) s(-1)). An attempted product study, using N2O5 as the NO3 source, failed since the alcohols react with N2O 5, producing alkyl nitrates. The estimated upper limit for rate coeffi cients for reaction of N2O5 with methanol, ethanol and propan-2-ol at 296 K in the gas phase were (2.0 +/- 1.0) x 10(-19), (3.9 +/- 2.0) x 1 0(-19) and (4.8 +/- 2.5) x 10(-19) cm(3) molecule(-1) s(-1), respectiv ely. The error limits correspond to the 95%-confidence interval.