KINETICS AND MECHANISM OF THE ATMOSPHERIC OXIDATION OF ETHYL TERTIARY BUTYL ETHER

Ethyl tertiary butyl ether (ETBE) is being proposed as an additive for use in reformulated gasolines. In this study, experiments were performed to examine the kinetics and mechanism of the atmospheric removal of ETBE. The kinetics of the reaction of ETBE with OH radicals were examined by using a relative rate technique with the photolysis of methyl nitrite to generate OH radicals. With n-hexane as the reference compound, a value of (9.73 +/- 0.33) x 10(012) cm3 molecule-1 s-1 was obtained for the rate constant. The OH rate constant for t-butyl acetate, a product of the oxidation of ETBE, was (4.4 +/- 0.4) x 10(-13) cm3 molecule-1 s-1 at 298 K. The primary products and molar yields for the OH reaction with ETBE in the presence of NO(x) were t-butyl formate (0.64 +/- 0.03), t-butyl acetate (0.13 +/- 0.01), ethyl acetate (0.043 +/- 0.003), acetaldehyde (0.16 +/- 0.01), acetone (0.019 +/- 0.002), and formaldehyde (0.53 +/- 0.04). Under the described reaction conditions, the formation of t-butyl nitrite was also observed. From these molar yields, approximately 98% of the reacted ETBE could be accounted for by paths leading to these products. Chemical mechanisms to explain the formation of these products are presented.