Selective Electrochemical versus Chemical Oxidation of Bulky Phenol
Published In
The Journal of Physical Chemistry B
Document Type
Citation
Publication Date
7-25-2016
Abstract
The electrochemical oxidation of selected tert-butylated phenols 2,6-di-tert-butyl-4-methylphenol (1), 2,6-di-tert-butylphenol (2), 2,4,6-tri-tert-butylphenol (3), 2-tert-butylphenol (4), and 4-tert-butylphenol (5) was studied in an aprotic environment using cyclic voltammetry, squarewave voltammetry, and UV−vis spectroscopy. All compounds exhibited irreversible oxidation of the corresponding phenol or phenolate ion. Compound 2 was selectively electrochemically oxidized, while other phenol analogues underwent mostly chemical oxidation. The electrochemical oxidation of 2 produced a highly absorbing product, 3,5,3′,5′-tetra-tertbutyl-4,4′-diphenoquinone, which was characterized by X-ray crystal diffraction. The electrochemical oxidation was monitored as a function of electrochemical parameters and concentration. Experimental and theoretical data indicated that the steric hindrance, phenoxyl radical stability, and hydrogen bonding influenced the outcome of the electrochemical oxidation. The absence of the substituent at the para position and the presence of the bulky substituents at ortho positions were structural and electrostatic requirements for the selective electrochemical oxidation.
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DOI
10.1021/acs.jpcb.6b06135
Persistent Identifier
http://archives.pdx.edu/ds/psu/18853
Citation Details
Zabik, N. L., Virca, C. N., McCormick, T. M., & Martic-Milne, S. (2016). Selective Electrochemical versus Chemical Oxidation of Bulky Phenol. The Journal of Physical Chemistry. B, 120(34), 8914-8924.