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S. Cotton's Lanthanide and Actinide Chemistry reports that naphthalene can be oxidized to naphthalene-1,4-dione using cerric ammonium sulfate (CAS), $\ce{MeCN, H2SO4},$ and $\ce{H2O}$.1 No mechanism was provided, and I was unable to find a complete mechanism for this transformation in the literature. From what I did find, Love et al.2 have reported the first step of this mechanism is the formation of the radical cation while the second step is the attack of a water molecule. After these two steps, the authors of the paper do not give any further information. I proposed a mechanism below, but I have a few concerns. To start, why is sulfuric acid used when protons seem to be lost during the transformation? I assume this is to prevent the cerium from reacting with the water to form hydroxides as it can be quite basic, but it is nonetheless unsettling.

CAS Oxidation of Naphthalene by CAS


References:

1Simon Cotton, In Lanthanide and Actinide Chemistry; Inorganic Chemistry, A Wiley Textbook Series, John Wiley & Sons, Ltd: Chichester, England, 2006 (ISBN-13: 978-0-470-01005-1).

2Brian E. Love, Alexander L. Simmons, "Substituent Effects in the Oxidation of 2-Alkyl-1,4-dialkoxybenzenes with Ceric Ammonium Nitrate," Tetrahedron Lett. 2016, 57(50), 5712-5715 (DOI: https://doi.org/10.1016/j.tetlet.2016.11.042).

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