Separation and characterization of lignite derived preasphaltenes by gel permeation chromatography and nuclear magnetic resonance spectrometry

摘要: Preasphaltenes for purposes of this study are defined as that portion a lignite derived product which is soluble in tetrahydrofuran but insoluble toluene. The preasphaltenes studied would fall into the seventh and eighth fractions sequential elution by solvent chromatography (SESC) procedure. preasphaltene fraction was chromatographed size separation using Bio-Beads S-X3 columns pyridine eluent. distribution functionality nitrogen oxygen were then monitored molecular formed at different operating conditions. shows structure most important parameter. Work centered on development procedures quantitation material. For report it only possible to identify amount phenolic hydroxyl groups present. Gel permeation offers opportunity observe subtle changes be rather difficult another postulated aromatic core plus ether links polymer requires precise information about concentration sites they change with weight. type suggested explain why benzene even through their acidities, bascities andmore » carbons may equal those asphaltenes. Their insolubilities result from furan linkages locking systems very rigid condensed molecules.« less