UV ABSORPTION-SPECTRA AND KINETICS FOR ALKYL AND ALKYL PEROXY-RADICALS ORIGINATING FROM DI-TERT-BUTYL ETHER

Alkyl, (CH3)(3)COC(CH3)(2)CH2, and alkyl peroxy, (CH3)(3)COC(CH3)(2)CH 2O2, radicals from di-tert-butyl ether (DTBE), have been studied in th e gas phase at 296 K. A pulse radiolysis UV absorption technique was u sed to measure the spectra and kinetics. Absorption cross sections wer e quantified over the wavelength range 220-330 nm. At 240 nm, sigma((C H3)3COC(CH3)2CH2) = (3.6 +/- 0.4) X 10(-18) cm(2) molecule(-1) and at 260 nm, sigma((CH3)3COC(CH3)2CH2) = (3.8 +/- 0.3) X 10(-18) cm(2) mole cule(-1) have been obtained. The observed rate constants for the self- reaction of (CH3)(3)COC(CH3)(2)CH2 and (CH3)(3)COC(CH3)(2)CH2O2 radica ls were found to be (2.9 +/- 0.2) X 10(-11) cm(3) molecule(-1) s(-1) a nd (2.7 +/- 0.2) X 10(-12) cm(3) molecule(-1) s(-1), respectively. For the reaction of the alkyl radical with O-2 in 1 atm pressure of SF6 a rate constant of (7.2 +/- 1.1) X 10(-13) cm(3) molecule(-1) s(-1) was found. The rate constants for the reaction of the alkyl peroxy radica ls with NO and NO2 were determined to be (1.8 +/- 0.2) X 10(-12) and ( 9.9 +/- 1.3) X 10(-12) cm(3) molecule(-1) s(-1), respectively. As a pa rt of the work the rate constants k(F + DTBE) and k(OH + DTBE) were de termined to be (2.6 +/- 0.6) X 10(-10) and (4.0 +/- 0.9) X 10(-12) cm( 3) molecule(-1) s(-1), respectively.