Application of liquid clathrates for separation of aromatic hydrocarbons from synthetic fuels

The high aromaticity of synthetic crudes from upgraded tar sands degrades mid-distillate fuel quality and incurs high costs through refining by hydrotreating. Recent work has demonstrated that a class of complex ionic liquids 'liquid clathrates' may be used to extract aromatic components from synthetic fuels at ambient temperatures. Liquid clathrates are formed by matching large organic cations, e.g., alkyl ammonium and alkyl pyridinium with air stable anions Al₂Cl₇- and AlCl₄- in the presence of an aromatic component. Such ternary mixtures typically form two liquid phases; the lower phase is salt-rich and contains a high concentration of aromatic components. Experimental details are given together with preparation procedures and extraction results determined by mass spectrometry and NMR spectroscopy.