Analysis of cationic and amphoteric surfactants I. Determination of their homolog distributions by gas chromatography on the basis of the Hofmann degradation

Abstract

Abstract A method (DMF‐Methylate method) has been described for the homolog analysis of cationic and amphoteric surfactants having a quaternary am‐monium group. The homolog distribution of cationic and amphoteric surfactants obtained by the DMF‐Methylate method closely agrees with that of the original alkyldimethylamines used. Therefore, the DMF‐Methylate method should be applicable to the homolog analysis of these surfactants. This method also offers qualitative information for the identifica‐tion of these surfactants, since the ratio of the α‐olefin to the alkyldimethylamine varies with each sur‐factant. On the basis of the analysis of the elimina‐tion products, it was confirmed that the main degra‐dation process was the elimination of a β‐hydrogen atom. This mechanism is different from that of the pyrolysis gas chromatography, which will be dis‐cussed elsewhere (S. Takano, M. Kuzukawa, and M. Yamanaka, in preparation).