BETA-CAROTENE: THERMAL DEGRADATION

Abstract

Thermal treatment of crystalline beta-carotene (240 degrees C in a vacuum) results in the formation of a volatile fraction containing chiefly aromatic hydrocarbons such as toluene, m- and p-xylene, 2,6-dimethylnaphthalene, and ionene. These compounds have been identified by means of gas-liquid chromatography, infrared spectroscopy, and, in the case of ionene, by additional nuclear magnetic resonance and mass spectroscopy. The principal degradation product is a yellowish-brown, glutinous mass which can be separated by means of preparative thin-layer chromatography in a number of fractions different in molecular weight. The structure of these fractions is not yet clear.