Abstract
• Kinetics of oxidation of certain polyols have been studied by Cornforth's and Corey-Suggs Cr(VI) compounds viz., Pyridinium dichromate (PDC), and Pridinium chlorochromate (PCC). • Under mineral acid-free conditions in aqous KHSO 4 medium. • Reactions obeyed second order kinetics with a first order in [PCC] (or [PDC]) and [Alcohol], and rate of oxidaion accelerated by increaing [KHSO 4 ]. • On the basis of observed results plausible mechanism involvement of ((PyH)CrO 3 + ) spesies and polyol (ROH) in the rate determining step is proposed in he case of PDC oxidation. • In the case of PCC oxidaion, the slow step involved [(PyH)OCrO(OH)Cl) + ], and ROH to give corresponding carbonyl compounds as products. Cornforth's Pyridinium dichromate (PDC), and Corey-Suggs Pyridinium chlorochromate (PCC) were accomplished as efficient reagents for selective oxidation of certain polyols (ROH) in aqueous KHSO 4 medium at different temperatures. Kinetic study of these reactions depicted second order kinetics with a first order in [PCC] or[PDC] and [ROH] in aqueous bisulfate medium. A ten-fold increase in KHSO 4 concentration increased the observed rate constant (k′) by ten times showing first order dependence on [KHSO 4 ]. Added olefinic monomers did not affect the rate of oxidation, indicating the absence of free radical intermediates. On the basis of observed kinetic features, participation of ((PyH)CrO 3 + ) and polyol (ROH) in the rate determining step to give products in PDC path. In the case of PCC system, the slow step involved [(PyH)OCrO(OH)Cl) + ], and ROH to give products.
Published Version
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