Silver dichromate, tetrakis oxidation

Many chromium oxidants suffer from problems of stability, light sensitivity or acidity, but tetrakis(py-ridine)silver dichromate is stable, nonphotosensitive, nonhygroscopic and a neutral oxidant It can be used to oxidize allylic and benzylic alcohols selectively in benzene. Unfortunately, it cannot be used in chlorinated solvents because it decomposes in these solvents. 

Common features of the tetrakis(pyridine)silver dichromate oxidations of vicinal and non-vicinal diols and their monoethers, aliphatic aldehydes, a-hydroxy acids (glycolic, lactic, malic and few substituted mandelic acids), and aliphatic primary alcohols in DMSO are = a + h[H+], fractional order in the substrates, = 5.91 (ethane diol), 5.80 (MeCHO), 5.78 (mandelic acid), and 5.85 (ethanol). The solvent effects have been analysed using Taft and Swain multiparametric equations for all the substrates except mandelic acid, for which the Kamlet and Swain multiparametric equation is used. The rate constants for aldehydes correlated with Taft s a values with a negative reaction constant. The rate-determining step for oxidation of aldehydes and hydroxy acids is the transfer of H ion. For diol oxidation, the... 

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