The gas-phase decomposition of alkoxy radicals

✍ Scribed by L. Batt

• Publisher: John Wiley and Sons
• Year: 1979
• Tongue: English
• Weight: 587 KB
• Volume: 11
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/kin.550110905

✦ Synopsis

It is shown that it is possible to obtain good data for the rate constant for the decomposition 01 alkoxy radicals [RO] by using nitric oxide a s a radical trap. Two experimental systems have been used.

T h e first system involves the use of dialkyl peroxides [(RO)?] a s thermal sources ofalkoxy radicals. The peroxide concentration was -10-4M, nitric oxide -2 X 10-4M, and the extent o f reaction was -10%. T h e total pressure was altered using carbon tetrafluoride a s an inert gas. T h e mechanism is

Hence Hs/R:, = k2[RO]/k:+. Our previous studies show that k? lies in the range

()I I) 3 i ( I 'M-

T h e second system employs alkyl nitrites (RONO] a s a thermal source of alkoxy radicals. T h e experimental conditions are very similar, except that we chose to use a n atmosphere of nitric oxide for initial experiments. If anything nitric oxide appears to be superior to carbon tetrafluoride as a n energy transfer agent. The mechanism is

( 2 )

Results are given for R = t-Am, s-Bu, t-Bu, i-Pr, Et, and Me. In addition the first unequivocal evidence is given for the pressure dependence of k:3 when R = t-Ru. T h e implications for atmospheric chemistry and combustion are also discussed.