Hydrochloric Acid → 4-Aminobenzoic Acid

Reaction equation

Cl[C:2]1[C:10](C)=[C:9](Cl)[C:8]([N+:13]([O-])=O)=[CH:7][C:3]=1C(O)=O.[O-]S(S([O-])=O)=O.[Na+].[Na+].Cl.[C:25](=[O:28])([O-])[O-:26].[Na+].[Na+]>COCCO.O>[CH:3]1[C:2]([C:25]([OH:26])=[O:28])=[CH:10][CH:9]=[C:8]([NH2:13])[CH:7]=1

Participants

Procedure

55 g of 2,4-dichloro-3-methyl-5-nitrobenzoic acid and 141.6 g of Na2S2O4 are boiled in a mixture of 440 ml of glycol monomethyl ether and 440 ml of water for 3 hours. 620 ml of 1/2-concentrated HCl are added to the still warm solution and the mixture is then boiled up once more. After cooling to room temperature, the mixture is poured into 1.5 l of water and brought to pH 5 with sodium carbonate. 24.6 g of aminobenzoic acid are obtained. Melting point: 202°-3°.