Studies on Analysis of Ingredients in Household Detergents. X.

Abstract

Polyoxyethylene (POE) fatty acid ester (1), POE glycerol fatty acid ester (2), POE hardened castor oil (3) and POE sorbitan fatty acid ester (4), all classsifyable as POE ester type nonionic surfactants, show similar IR and NMR spectra. For this reason, identification of these surfactants by means of spectroscopy has been difficult. But, from a detailed analysis of the NMR spectar of these nonionics, it was found that each has a characteristic signal specific for its structure. From the study of 1H-NMR, (3) was identified by the appearance of signals at 4.9 and 1.5ppm along with those of the alkyl, POE, and the ester groups. Similarly, (4) was identified by the signals at 4.5 and 4.7ppm. (1) and (2) could not be identified by 1H-NMR measurements since they have no characteristic signal. But by 13C-NMR spectroscopy, (1) and (2) were identified. The appearance of a signal at 78.9ppm indicates that the spectrum belongs to (2) and its disappearance to (1). These data show that either 1H-NMR or 13C-NMR spectroscopy is effective for identifying POE ester type nonionic surfactants.