KINETIC H/D ISOTOPE EFFECTS FOR GAS-PHASE HYDROXYLATION OF BENZENE AND CHLOROBENZENE BETWEEN 520-1080 K - HYDROXYL RADICAL VERSUS O(3P) ATOM ATTACK
KINETIC H/D ISOTOPE EFFECTS FOR GAS-PHASE HYDROXYLATION OF BENZENE AND CHLOROBENZENE BETWEEN 520-1080 K - HYDROXYL RADICAL VERSUS O(3P) ATOM ATTACK
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DOI：
10.1002/kin.550200707
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发表时间：
1988-07-01
影响因子：
1.5
通讯作者：
LOUW, R
中科院分区：
文献类型：
--
作者：
MULDER, P;LOUW, R
Gas phase slow combustion of (chloro)benzene in O2/N2mixtures, and induced by addends such as tert butylhydroperoxide, cyclohexane, or methanol, leads to (chloro)‐phenol as the only important aromatic product. Using C6H6/C6D6mixtures, formation of phenol/perdeuterophenol was studied between 520–1080 K. The temperature dependence of this product ratio was found to obey the Arrhenius expression for the intermolecular isotope effect logkH/kD= −0.14 ± 0.03 + (1240 ± 80)/2.303RT(Rin cal/mol K). Essentially the same result was obtained for the intramolecular isotope effect, measuring the change in isomer distribution for the chlorophenols formed from p‐deuterio‐chlorobenzene versus those for chlorobenzene.These results are in accordance with H(D)‐abstraction by ·OH, via a linear transition state, as the first and (relative) rate determining step. Whereas above 1000 K, at reduced pressure, the intramolecular isotope effect continues to prevail, C6H6/C6D6do not show differences in rate of formation of C6H5OH/C6D5OH. Under these conditions, the only effective reaction of arene to phenol appears to be set in by addition of O(3P).
