Describe the following: Decarboxylation

Decarboxylation: Decarboxylation refers to the reaction in which carboxylic acids lose carbon dioxide to form hydrocarbons when their sodium salts are heated with soda lime. Example: CH 3 COONa → △ NaOH and CaO CH 4 + Na 2 CO 3 Decarboxylation also takes place when aqueous solutions of alkali metal salts of carboxylic acids are electrolysed. This electrolytic process is known as Kolbe's electrolysis.

Describe the following: Cannizzaro reaction

Cannizzaro reaction: The self oxidation-reduction (disproportionation) reaction of aldehydes which do not have α -hydrogen atom, on treatment with concentrated alkali is known as the Cannizzaro reaction. In this reaction, two molecules of aldehydes participate where one is reduced to alcohol and the other is oxidised to carboxylic acid. For example, when methanal is treated with concentrated potassium hydroxide, methanol and potassium methanoate are produced. 2 HCHO → Con . KOH CH 3 OH + HCOOK

Predict the major product of acid catalysed dehydration of 1-methylcyclohexanol.

Acid catalysed dehydration of 1 - methylcyclohexanol is as follows: The Sulphuric acid or Phosphoric acid is used in these reactions as they are good dehydrating agents. According to Saytzeff Rule, the alkene having more number of carbon groups attached to the double bonded carbon is obtained in more proportion. Therefore, the major product is 1-methyl cyclohexene.