Separation and characterization of components of catalytic cracker feed using centrifugal partition chromatography

Abstract

Centrifugal partition chromatography (CPC) was used to fractionate a catalytic-cracking feedstock (i.e., catalytic cracker feed) into 16 separate fractions in the descending mode and 5 fractions in the inverse or ascending mode. Each fraction was analyzed by UV, fluorescence, and synchronous luminescence (SL) spectroscopy as well as by gas chromatography/mass spectrometry (GC/MS). It appeared that CPC can be used to fractionate larger samples of this type and with a greater degree of selectivity than previously reported preparative HPLC approaches. The SL spectra tended to be much more useful and information-rich for these complex mixtures as compared to UV or fluorescence spectra. GC/MS of each fraction allowed identification of specific components. In this way the selectivity of the CPC separation could be accessed. It was found that CPC effectively separated catalytic cracker feed into fractions by polarity, aromaticity, and alkyl substitution patterns. In addition, fractionation by heteroatom type and of homologues was observed. The aromatic content found by gravimetry after CPC separation matched well with the aromatic content measured by UV spectrometry. 29 refs., 6 figs., 2 tabs.