• Nitriles?are compounds with a -CN functional group
• They can be prepared from the?nucleophilic substitution?of halogenoalkanes

Propanenitrile, an example of a nitrile

Reaction with KCN

• The?nucleophile?in this reaction is the?cyanide, CN^-?ion
• Ethanolic?solution?of?potassium?cyanide?(KCN in ethanol) is?heated?under?reflux?with the halogenoalkane
• The product is a?nitrile

Bromoethane reacts with ethanolic potassium cyanide when heated under reflux to form propanenitrile

• Hydroxynitriles?are compounds with both a hydroxy (-OH) and cyanide (-CN) functional group
• They can be prepared from the?nucleophilic addition?of?aldehydes?and?ketones

2-hydroxy-2-methylpropanenitrile

Reaction with HCN

• The nucleophilic addition of hydrogen cyanide to carbonyl compounds is a two-step process
• In?step 1,?the cyanide ion?attacks?the carbonyl carbon to form a negatively charged intermediate
• In?step 2,?the negatively charged oxygen atom in the reactive intermediate quickly reacts with aqueous H+?(either from HCN, water or dilute acid) to form a 2-hydroxynitrile

The cyanide ion attacks the carbonyl carbon to form a negatively charged intermediate which quickly reacts with a proton to form a 2-hydroxynitrile compound

• Nitriles?are hydrolysed by either?dilute acid?or?dilute?alkali followed by?acidification?to give a carboxylic acid
  • Hydrolysis is the breakdown of a compound using water

Hydrolysis of nitriles

• Nitriles are?hydrolysed by?either?dilute acid?or?dilute alkali followed by acidification
  • Hydrolysis by dilute acid results in the formation of a carboxylic acid and ammonium salt
  • Hydrolysis by dilute alkali results in the formation of a sodium carboxylate salt and ammonia;?Acidification?is required to change the carboxylate ion into a carboxylic acid
• The -CN group at the end of the hydrocarbon chain is converted to a -COOH group

Hydrolysis of nitriles by either dilute acid (1) or dilute alkali and acidification (2) will form a carboxylic acid