Purification of α-Olefins for Removing Colored Substances in Sulfonation Process

Abstract

Commercial α-olefins, used as a raw material for α-olefin sulfonates (AOS) which are new and promising active ingredient of synthetic detergents, may be furnished by thermal cracking of petroleum wax and Ziegler's ethylene polymerization.α-Olefins obtained from wax cracking contain impurities which give so intensively colored products that bleaching is required, in the sulfonation process with gaseous sulfur trioxide.An effective treatment was attained for removing impurities from the α-olefin feed by mixing with urea to form adduct followed by the separation from the impurities. The separated impurities were identified by chromatography as cyclic compounds composed of more than 140 components. When the cyclic compounds were treated with sulfuric acid, an intensive coloration was observed.As an another procedure for removing these impurities, the treatment with Friedel-Crafts catalyst such as anhydrous ferric chloride or boron trifluoride, was also promising.