Background for Carboxylic Acids and Derivatives
A carboxylic acid contains an hydroxide attached to C of C=O group (carbonyl group). An acid halide contains a halogen attached to the C of the C=O group. An ester contains an alkoxy group attached to a C of a C=O. An anhydride contains two C=O separated by an oxygen. An amide contains a nitrogen attached to C of a C=O. The carbon in the carbonyl is sp2 hybridized, has a bond angle of 120o, and is trigonal planar. Carboxylic acids, primary amides, and secondary amides have intermolecular hydrogen bonding. Carboxylic acids, primary amides, and secondary amides have higher melting points and boiling points than other carboxylic acid derivatives.
Uses of Carboxylic Acids and Derivatives
Esters, tertiary amides, and nitriles are used as solvents. Formic acid is in ant bites. Acetic acid is used as vinegar.
Nomenclature of Carboxylic Acids and Derivatives
In a carboxylic acid, the longest continuous carbon chain is the parent compound. Number the chain so that the C at the C=O is position 1. From the alkyl prefixes, use Aanoic acid.@ Name and number substituents. An acid halide is named as alkanoyl halide. An ester is named as an alkyl alkanoate. An anhydride is named as an alkanoic alkanoic anhydride. An amide is named as an alkanamide.
Synthesis of Carboxylic Acids
Zero and primary alcohols are oxidized with sodium dichromate, potassium dichromate, potassium permanganate, sodium hypochlorite, nitric acid, or chromium trioxide to form carboxylic acids. Aldehydes are oxidized with sodium dichromate, potassium dichromate, potassium permanganate, sodium hypochlorite, nitric acid, or chromium trioxide to form carboxylic acids. Alkyl magnesium halide is treated with carbon dioxide, followed by hydrolysis, yields a carboxylic acid. Nitriles are hydrolyzed to yield carboxylic acids.
Reactions of Carboxylic Acids
Reduction of carboxylic acids with lithium aluminum hydride yield alcohols. Carboxylic acids react with thionyl chloride to give acid chlorides, sulfur dioxide, and hydrogen chloride. The reaction of carboxylic acids with alcohols, in the presence of acid, yield esters. Carboxylic acids react with acid chlorides to give anhydrides.
Reactions of Acid Halides
Acid chlorides are hydrolyzed to carboxylic acids. Acid chlorides react with alcohols to form esters. Acid chlorides react with amines to form amides. Reduction of acid chlorides with lithium aluminum hydride form alcohols and with lithium aluminum tri(t-butoxy) hydride form aldehydes. Acid chlorides react with dialkyl lithium cuprates to yield ketones.
Reaction of Amides
Esters are hydrolyzed to carboxylic acids and alcohols. Esters react with lithium aluminum hydride, followed by hydrolysis, to yield alcohols. Esters react with amines to produce amides and alcohols.
Reactions of Anhydrides
Anhydrides are hydrolyzed to produce carboxylic acids. Anhydrides react with alcohols to produce esters and carboxylic acids. Anhydrides react with amines to produce amides and carboxylic acids.
Reaction of Amides
Amides are hydrolyzed with acid to yield carboxylic acids and ammonium ions. Amides are hydrolyzed with base to yield the anions of carboxylic acids and amines. Reduction of amides with lithium aluminum hydride yield amines. Primary amides are dehydrated with phosphorus oxychloride or diphosphorus pentoxide to yield nitriles.