Oxidation activated manganese dioxide-silica

Silver permanganate and potassium permanganate on silica gel, or mixtures of silver oxide and manganese dioxide on the same support, show good activity in the absence of oil and water vapor (15), and a mixture of silver permanganate and manganese dioxide was rather active in the presence of water vapor (15). 

Pyridinium chlorochromate has also been used (Chakraborty and Bordoloi, 1999) under microwave irradiation for the oxidation of alcohols to the corresponding carbonyl functions with an efficient and mild methodology. Microwave irradiation of alcohols with silica supported active manganese dioxide in solvent-free condition provides rapid and selective oxidation of alcohols to the corresponding carbonyl compounds (Varma et al., 1997). 

The time required to achieve complete reaction varies from 20-48 hr depending on the activity of the manganese dioxide. The progress of the oxidation is easily monitored by TLC analysis on silica gel. 

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