TY - JOUR
T1 - Chromic acid oxidation of benzhydrols-kinetics and mechanism
AU - Sadagopa Ramanujam, V. M.
AU - Venkatasubramanian, N.
AU - Sundaram, S.
N1 - Funding Information:
One of us (V.M.S.R.) thanks Professor H. C. Brown, Purdue University, Indiana, U.S.A., for providing the substituted benzhydrols and Professor C. N. Pillai, Department of Organic Chemistry, I.I.T., Madras, India, for his help in infrared, n.m.r. and mass spectral analyses of benzhydrol[cr-Dl. He also wishes to express his gratitude to the Department of Preventive Medicine and Community Health, UTMB, Texas, U.S.A., for the assistance offered during the preparation of the manuscript. Partial support from the Robert A. Welch Foundation Grant H-416 (to Dr N. M. Trieff) is also gratefully acknowledged by V.M.S.R.
PY - 1977
Y1 - 1977
N2 - The kinetics of the oxidation of benzhydrol (diphenylmethanol) and several of its substituents by chromium(VI) oxide in aqueous acetic acid have been studied in detail. The rate of oxidation is expressed as v = k3[ArAr’CHOH][CrVI][H+]2 The effect of ring substituents on the rate gives a p+ value of -0.546 (r = 0.959) pointing to the development of an electron-deficient centre in the transition state. The oxidation of benzhydrol[α-D] proceeds 6.5 times slower than that of its protio analogue at 55°C. From the Arrhenius plots, activation parameters have beep evaluated and the isokinetic relationship has been analysed. The results are discussed in terms of a mechanism involving a rate-determining loss of hydride ion from the α-carbon of benzhydroxy chromate ester.
AB - The kinetics of the oxidation of benzhydrol (diphenylmethanol) and several of its substituents by chromium(VI) oxide in aqueous acetic acid have been studied in detail. The rate of oxidation is expressed as v = k3[ArAr’CHOH][CrVI][H+]2 The effect of ring substituents on the rate gives a p+ value of -0.546 (r = 0.959) pointing to the development of an electron-deficient centre in the transition state. The oxidation of benzhydrol[α-D] proceeds 6.5 times slower than that of its protio analogue at 55°C. From the Arrhenius plots, activation parameters have beep evaluated and the isokinetic relationship has been analysed. The results are discussed in terms of a mechanism involving a rate-determining loss of hydride ion from the α-carbon of benzhydroxy chromate ester.
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U2 - 10.1071/CH9770325
DO - 10.1071/CH9770325
M3 - Article
AN - SCOPUS:84971086453
SN - 0004-9425
VL - 30
SP - 325
EP - 334
JO - Australian Journal of Chemistry
JF - Australian Journal of Chemistry
IS - 2
ER -