Minor processes in the photolysis of azomethane at low pressure: An upper limit for the rate of the unimolecular elimination of H2 from vibrationally excited ethane
✍ Scribed by J. M. Roscoe; C. Blatt; R. A. Back
- Publisher
- John Wiley and Sons
- Year
- 1991
- Tongue
- English
- Weight
- 332 KB
- Volume
- 23
- Category
- Article
- ISSN
- 0538-8066
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✦ Synopsis
The photolysis of azomethane in the near UV has been studied at room temperature and pressures from 10 mtorr to 10 torr. The main products, CzHs and Nz, accounted for more than 9% of the reaction. Minor hydrocarbon products observed were (with quantum yields) C ~H B (3.5 x and n-C4Hlo (trace). Quantum yields of Hz of 4 x and 2 x W5 were measured at azomethane pressures of 0.1 and 1.0 torr, respectively. The minor hydrocarbon products can be accounted for by reactions of CH3 and CzH5 radicals following hydrogen abstraction from azomethane by CH3. The Hz product observed represents an upper limit for the Hz elimination from vibrationally excited CZHG formed by CH3 combination in the system, corresponding to a rate of elimination ca. 5 x times the competing rate of dissociation to 2CH3. Assuming a frequency factor of lOI3 s-l for the Hz elimination, a lower limit of about 90 kcal mol-' was estimated for the energy barrier. CzH4 (3.2 x CH4 (3 x