- Thermal reaction of (CH3)2C=C(CH3)2 in the presence of di-tert-butyl peroxide; reactions of the radicals ·CH3, (CH3)3C·C(CH3)2 and (CH3)2C=C(CH3)·CH2
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A study of the thermal reaction of (CH3)2C=C(CH3)2 (23DMB2) in the presence of di-t-butyl peroxide (PODBT) at 389-451 K yielded kinetic data on some reactions of the radicals ·CH3, (CH3)3C·C(CH3)2 (1122TMP·) and (CH3)2C=C(CH3) ·CH2 (112TMA·). The ratio of the cross-combination ratios of the radicals o(112TMA·, 122TMP·)/φ(·CH3, 1122TMP·) and the rate constant for H-abstraction from 23DMB2 by ·CH3 relative to that of the recombination reaction, ·CH3 + (CH3)2C=C(CH3)2 → CH4 + (CH3)2C=C(CH3) ·CH2 (4) 2·CH3 → C2H6 (7) have been determined. The values are φ(1122TMP·, 112TMA·)/φ(·CH3, 1122TMP·) = 0.9 ± 0.3 log(k4/k71/2) = (3.74 ± 0.21) - (36.3 ± 2.2)/Θ where Θ = RT ln 10 and the units are dm3/2 mol-1/2 s-1/2 for k4/k71/2, and kJ mol-1 for the energy of activation.
- Koertvelyesi,Seres
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p. 253 - 273
(2007/10/03)
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- EXCIPLEX AND RADICAL ION INTERMEDIATES IN THE PHOTOCHEMICAL REACTION OF 9-CYANOPHENANTHRENE WITH 2,3-DIMETHYL-2-BUTENE
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The photochemical reaction of 9-cyanophenanthrene and 2,3-dimethyl-2-butene, first reported by Mizuno, Pac and Sakurai, has been reinvestigated.The formation of a -cycloadduct via a singlet exciplex is the exclusive reaction in the nonpolar solvents benzene and ethyl acetate.Photochemical behavior in polar solvents is far more complicated than previously reported.Mechanisms consistent with the effects of solvent polarity, methanol concentration, methanol deuteration, and light intensity upon product yields are proposed.Formation of a 9-cyanophenanthrene anion radical and 2,3-dimethyl-2-butene cation radical is the primary photoinitiated process in polar solvent.The cation radical can undergo deprotonation to yield an allyl radical or nucleophilic attack by methanol to yield a methoxyalkyl radical.Covalent bonding of these radicals and the 9-cyanophenanthrene anion radical gives rise to the acyclic adducts obtained in polar solvents.The anion radical can also be protonated, leading ultimately to the formation of 9,10-dihydro-9-cyanophenanthrene.
- Lewis, Frederick D.,DeVoe, Robert J.
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p. 1069 - 1078
(2007/10/02)
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