DETERMINATION BY HIGH-PERFORMANCE CAPILLARY ELECTROPHORESIS OF ALKYLAROMATICS USED AS BASES OF SULFONATION IN THE PREPARATION OF INDUSTRIAL SURFACTANTS

Having previously attempted to determine by high-performance capillary electrophoresis (HPCE) industrial surfactants resulting from the sulfonation of oil fractions (WITCO TRS 10-80), it was decided, because of the complexity of these fractions and of the low resolution obtained, to undertake the analysis by HPCE of mixtures of alkylaromatics used as bases to prepare these compounds. Using a model mixture of alkylbenzenes, including benzene and a series of homologous compounds with alkyl chain lengths of C-1-C-16, the conditions of the separation were optimized. It was shown that it is possible to analyse this mixture, with total baseline resolution, in 35 min using simultaneously sodium dodecyl sulfate and an organic co-solvent at high concentrations. These conditions also allow the resolution not only of the alkylated compounds used as the bases for the preparation of industrial alkylbenzenesulfonates (Sulframine ACB and Sulfo TPB) but also the surfactants themselves. It must also be noted that these conditions, transposed to WITCO TRS 10-80, allow for the first time the resolution of this complex mixture.