Reaction of the Nitrate Radical with Some Potential Automotive Fuel Additives. A Kinetic and Mechanistic Study

Article abstract of DOI:10.1021/j100074a015

Rate coefficients for the reaction of NO3 with ethyl tert-butyl ether (ETBE), diisopropyl ether (DIPE), and tert-amyl methyl ether (TAME) have been determined.Absolute rates were measured at temperatures between 257 and 367 K using the fast flow-discharge (FFD) technique.Relative rate experiments were also performed at 295 K in a reactor equipped with White optics and using FTIR spectroscopy to follow the reactions.Rate data from FFD experiments can be presented as follows: k_ETBE=(2.48 +/-0.78)E-12exp<-(1613 +/-542)/T>, k_DIPE=(2.02 +/-0.35)E-12exp<-(1759 +/-301)/T>, and k_TAME=(1.21 +/-0.22)E-12exp<-(1874 +/-304)/T> (in units of cm³ molecule^-1 s^-1).The rate coefficients at room temperature from the FFD experiments are in goog agreement with the corresponding rate coefficients from the relative experiments.Products from simulated atmospheric oxidation of the investigated ethers, initiated by the reaction with nitrate radical, were identified using FTIR spectroscopy.The degradation of ETBE results in tert-butyl formate, tert-butyl acetate, formaldehyde, and methyl nitrate, that of DIPE in acetone, isopropyl nitrate, isopropyl acetate, and formaldehyde, and that of TAME in tert-amyl formate, formaldehyde, and tert-amyl nitrate.