UV absorption spectra and kinetics for alkyl and alkyl peroxy radicals originating from di-tert-butyl ether

Abstract

Alkyl, (CH3)3COC(CH3)2CH2, and alkyl peroxy, (CH3)3COC(CH3)2CH2O2, radicals from di-tert-butyl ether (DTBE), have been studied in the gas phase at 296 K. A pulse radiolysis UV absorption technique was used to measure the spectra and kinetics. Absorption cross sections were quantified over the wavelength range 220-330 nm. At 240 nm, σ(CH3)3COC(CH3)2CH2 = (3.6 ± 0.4) × 10-18 cm2 molecule-1 and at 260 nm, σ(CH3)3COC(CH3)2CH2O2 = (3.8 ± 0.3) × 10-18 cm2 molecule-1 have been obtained. The observed rate constants for the self-reaction of (CH3)3COC(CH3)2CH2 and (CH3)3COC(CH3)2CH2O2 radicals were found to be (2.9 ± 0.2) × 10-11 cm3 molecule-1 s-1 and (2.7 ± 0.2) × 10-12 cm3 molecule-1 s-1, respectively. For the reaction of the alkyl radical with O2 in 1 atm pressure of SF6 a rate constant of (7.2 ± 1.1) × 10-13 cm3 molecule-1 s-1 was found. The rate constants for the reaction of the alkyl peroxy radicals with NO and NO2 were determined to be (1.8 ± 0.2) × 10-12 and (9.9 ± 1.3) × 10-12 cm3 molecule-1 s-1, respectively. As a part of the work the rate constants k(F + DTBE) and k(O + DTBE) were determined to be (2.6 ± 0.6) × 10-10 and (4.0 ± 0.9) × 10-12 cm3 molecule-1 s-1, respectively. © 1995.