Abstract

Dayan lignite was subjected to thermal dissolution sequentially with cyclohexane, acetone and methanol. Each thermal dissolution extract was subjected to further separation/enrichment using a column chromatography, which was sequentially eluted with petroleum ether, a mixture of ethyl acetate and petroleum ether (vol:vol = 1:1), and ethyl acetate. The 3 thermal dissolution extracts and 9 enrichment sub-fractions were characterized by an Orbitrap mass spectrometry (MS) equipped with an atmospheric pressure chemical ionization ion source. The MS data were also statistically analyzed by principal component analysis, which can reduce the dimensionality of data and classify multiple samples according to principal components. Identified compounds in the extracts and sub-fractions are classified into 8 classes according to the heteroatom distribution. Hydrocarbon class is mainly presented in the petroleum ether fraction, and oxygen class, nitrogen class and oxygen-nitrogen class are distributed in both petroleum ether/ethyl acetate and ethyl acetate sub-fractions. The combination of different analytical methods enhances the understanding of a coal at the molecular level and provides important data for downstream refining processes. This article is protected by copyright. All rights reserved.