Peresters XIII. Solvent effects in the decomposition of t-butylperoxy α-phenylisobutyrate with special reference to the cage effect
✍ Scribed by Frank E. Herkes; Juliette Friedman; Paul D. Bartlett
- Publisher
- John Wiley and Sons
- Year
- 1969
- Tongue
- English
- Weight
- 663 KB
- Volume
- 1
- Category
- Article
- ISSN
- 0538-8066
No coin nor oath required. For personal study only.
✦ Synopsis
t-Butylperoxy or-phenylisobutyrate (I) decomposes thermally by concerted formation of carbon dioxide, t-butoxy, and cumyl radicals. Radical pair return in the solvent cage therefore does not affect the observed rate of decomposition, but is readily determined by means of galvinoxyl and other scavengers. In a series of 15 solvents the rate constant varies over a 2.8 fold range, being fastest in aromatic solvents. I n the same solvent series the relative rates of diffusion and combination of radicals, measured by the cage effect, change by tenfold and are largely determined by the viscosity of the solvent. In all solvents of 7 > 8 mP, the reciprocal of the cage effect is a linear function of ( T1'2/q), as recently observed for trifluoromethyl and methyl radicals [16]. This property of the cage effect provides a test by which it can be distinguished from other processes that reduce the efficiency of free-radical production from a n initiator.