ORGANIC CHEMISTRY
CARBONYL COMPOUNDS (L-6) B.SC. II BY DR. MONIKA GUPTA
Dr. Monika Gupta, Vaish College, Rohtak Oxidation of Aldehydes and Ketones
Aldehydes and ketone vary in their oxidation reactions but aldehydes can easily undergo oxidation to form carboxylic acids with known oxidizing agents such as potassium dichromate, potassium permanganate, and nitric acid, etc. Moreover, mild oxidizing agents such as Tollen’s reagents and Fehling’s reagent are also capable of oxidizing only aldehydes.
Dr. Monika Gupta, Vaish College, Rohtak Oxidation of Aldehydes
Dr. Monika Gupta, Vaish College, Rohtak Oxidation of ketones
Oxidation of ketones requires carbon-carbon bond cleavage so that the reaction can produce carboxylic acid containing a lesser number of bonds with respect to the parent ketone.
Dr. Monika Gupta, Vaish College, Rohtak Reaction with Mild Oxidizing agents
Mild oxidizing agents can be used for distinguishing between aldehydes and ketones. Now, we will how Mild oxidizing agents like Tollen’s reagent and Fehling’s solution is used for distinguishing between the aldehydes and ketones.
Dr. Monika Gupta, Vaish College, Rohtak Reaction with Tollen’s Reagent
Aldehydes readily undergo oxidation with Tollen’s Reagent whereas ketones are not. Tollen’s reagent is a colourless, basic ammoniacal silver nitrate solution
Dr. Monika Gupta, Vaish College, Rohtak Tollen’s Test (Silver Mirror Test)
It is a very common qualitative laboratory test help in differentiating between aldehydes and ketones. Aldehydes form silver mirror while ketones does not.
Dr. Monika Gupta, Vaish College, Rohtak Fehling’s reagent
Fehling’s Reagent consists of a mixture of two solutions (Fehling Solution A & B). Fehling solution A is made up of aqueous copper sulfate and Fehling solution B is made up of Rochelle salt or alkaline sodium potassium tartrate. Prior to the test equal quantity of both the solutions are mixed together.
Dr. Monika Gupta, Vaish College, Rohtak Fehling’s Test
The reaction requires heating of aldehyde with Fehling’s Reagent which will result in the formation of a reddish-brown colour precipitate.. However, aromatic aldehydes do not react to Fehling’s Test. Moreover, ketones do not undergo this reaction. Thus, we can differentiate between aldehydes and ketones.
Dr. Monika Gupta, Vaish College, Rohtak Contd.
Dr. Monika Gupta, Vaish College, Rohtak Methyl Ketone Oxidation by Haloform Reaction
Haloform reaction is one of the particular types of alpha halogenation reaction. The reaction occurs in the methyl ketones and converts the methyl group into haloform leaving the group. The reaction can include chloroform, bromoform, and iodoform solid precipitate. This reaction helps to detect the presence of methyl ketones in the laboratories.
Dr. Monika Gupta, Vaish College, Rohtak Haloform Reaction
Dr. Monika Gupta, Vaish College, Rohtak Baeyer‐Villiger Oxidation
It is another example of ketone oxidation. We know that ketone requires a strong oxidizing agent such as peroxybenzoic acid. For instance, phenyl methyl ketone undergoes oxidation by peroxybenzoic acid to produce phenylacetate.
Dr. Monika Gupta, Vaish College, Rohtak