Tuesday, February 5, 2008

Reduction - Aldehydes - Ketones

Oxidation of Aldehydes by Silver Oxide: Reaction of simple aldehydes with aqueous Ag2O in the presence of NH3 yields the corresponding carboxylic acid and metallic silver. The silver is generally deposited in a thin metallic layer which forms a reflective "mirror" on the inside surface of the reaction vessel. The formation of this mirror forms the basis of a qualitative test for aldehydes, called the Tollens Test.

Oxidation of Aldehydes to form Carboxylic Acids: Reaction of simple aldehydes with acidic MnO4-, or CrO3/H2SO4 yields the corresponding carboxylic acid. Aldehydes oxidize very easily and it is often difficult to prevent oxidation, even by atmospheric oxygen.

Oxidation of Ketones: Ketones are more resistant to oxidation, but can be cleaved with acidic MnO4- to yield carboxylic acids.

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