Fractionation of soluble portion of reductively alkylated bituminous coals

Abstract

Five bituminous coals were reductively alkylated with potassium and 1-butyl iodide in THF. The benzene soluble portion of reductively butylated coals were separated into the saturates, aromatics, neutral heterocyclics, ethers and polar compounds on a silica gel column. From the saturates, the n-alkanes were isolated by the thin-layer and column chromatography on silica gel, and then analyzed by GC. The aromatics were fractionated on a dual packed SiO2/Al2O3 column. The mono- and diaromatic fractions obtained were studied by GC-MS method. The non-hydrocarbon and polar compounds were charcterized by elemental composition, VPO molecular weight and both IR and 1H NMR spectra. The asphaltenes from one reductively butylated coal were fractionated into basic and acidic/neutral parts after bubbling dry HCl gas through their benzene solution. A concept that benzene eluates collect C-alkylation products and diethyl ether + THF mixtures collect the products of O-alkylation was evolved. The ratio of C-alkylation to O-alkylation was found to be a function of the C content of the initial coals.