Characterization of dissolution products from two turkish lignites by 1H NMR, IR and GC techniques

Abstract

Some structural features of the dissolution products from two Turkish lignites (Beypazari and Tuncbilek lignites) have been investigated with proton nuclear magnetic resonance and infra-red spectroscopies and gas chromatography. The results indicate that, in general, no substantial changes occur in the structural characteristics of the soluble products obtained from different extraction conditions. This is true especially for preasphaltene and asphaltene fractions. On the other hand, some structural differences were observed in the compositions of oil fractions, especially in the neutral fraction of oils from the different experimental conditions. The neutral oils from the low temperature and short time extractions are mainly consisted of alkylated aromatics and include a very small quantity of longer chain paraffins. Whereas, the oils from the extractions at high temperatures and longer times, include several long straight-chain paraffins (C15 - C32) with higher quantity. Hydrogen atmosphere is moderately effective for deoxygenation of the products. Dealkylation reactions for smaller molecules are insignificant but hydrogen atmosphere is relatively effective for the dealkylation of larger molecules. Higher temperature and longer extraction period accelerate the liquid phase pyrolysis. © 1991, Taylor & Francis Group, LLC. All rights reserved.