Separation, Analysis And Directional Transformation Of Karamay Natural Bitumen

Karamay Natural Bitumen (KNB) was sequentially extracted with methanol, ethanol,acetone, ethyl acetate, petroleum ether and carbon disulfide under ultrasonic irradiation in thisstudy. Six extracts E1, E2, E3, E4, E5, E6and the extraction residue were obtained. The extractsE1to E5were separated and purified using column chromatography with silica gel and somecolumn chromatography fractions were obtained. KNB was subject to ruthenium ion-catalyzedoxidation and sodium oxidation. KNB, all extractions and the extraction residue were analyzedusing Fourier transform infrared spectroscopy instrument （FTIR） to explore their structurefeatures. All extractions, some fractions of column chromatography and the oxidation productswere analyzed by gas chromatography/mass spectrometry analysis (GC/MS). The mainconclusions are as follows.The extraction yields and physical properties of each extract were significantly differentafter deep extraction. E1was enriched in a large amount of saturated alkanes compounds withhydroxyl functional group. Some n-alkanes, branched alkanes and small amounts of aromaticcompounds were detected in E2. E3was aboundant of terpane compounds, sterane compoundsand phthalates compounds and E4was enriched in aromatic compounds and phthalatescompounds. The compounds in E5and E6were mainly macromolecular compounds whichwere beyond the detection range of GC/MS.The variety and quantity of the GC/MS detectable compounds increased significantly aftercolumn chromatography separation. Polar solvents had good selectivity to terpane compounds,sterane compounds, aromatic compounds and fatty acid ester. Intermediate sovents had goodeluting effect for phthalates compounds and non-polar solvents such as petroleum ether andcarbom disulfide had good selectivity to n-alkanes, branched alkanes and cyclanes compounds.The oxidation products of KNB mainly included aliphatic monocarboxylic acids, aliphaticdicarboxylic acids, aliphatic trcarboxylic acids and aromatic polycarboxylic acids. It caninferred that there were considerable amount of aromatic hydrocarbons with the alkyl sidechain. However, the amount of benzene ring structure linked with bridge bond and condensedaromatic rings was small.There were a large number of biomarkers in extracts and it can be conferred that Karamaynatural bitumen was of higher maturity and there was almost no biodegradation in the processof diagenesis. The formation of KNB’s geographic environment may be ocean or lake, and theterrestrial substances, bacteria, algae and some higher plants made great contribution.KNB could be separated preliminarily by fractional extraction, and it could be furtherseparated and purified through chromatography. Oxidation provides some theoretical data to reveal the original structure and composition of natural bitumen at the molecular level and animportant technology for high value-added use of natural bitumen.This study provides aneffective way to selectively separate, analyze and directionally transformate KNB, and thenreveal the composition and distribution discipline of organic matter in natural bitumen, whichenriches the knowledge of its organic geochemistry.