Thermometric determination of aromatic aldehydes

Abstract

The thermometric determination of some aromatic aldehydes is described. A known and excess amount of 2,4-dinitrophenylhydrazine is added to the aldehyde to be determined and, after stirring the mixture for 10 to 15 minutes, the excess of 2,4-dinitrophenylhydrazine is titrated with a standard aldehyde, namely 2-methoxybenzaldehyde. The solvent used for both titrant and titrand is a solution of 4 per cent. v/v of water and 4 per cent. v/v of sulphuric acid in isobutyl alcohol. The time of titration is about 1 minute and the accuracy is within ±1 per cent.