Molecular Characterization Of Hydrocarbons In Petroleum Fractions By Combining Chemical Derivatization Reactions With High-resolution Mass Spectrometry

Saturated hydrocarbons and aromatic hydrocarbons are the main and high-value components of petroleum.In-depth study on the molecular composition of hydrocarbons in petroleum can provide basic experimental data for the development of molecular management and efficient utilization of petroleum resources.In this study,the method of molecular characterization of petroleum hydrocarbons by combining with chemical derivatization and high-resolution electrospray ionization mass spectrometry were investigated,and the related reaction conditions and the basis of methodology were further improved.In addition,combining the method with other analytical methods,a scheme for comprehensive molecular composition analysis of heavy petroleum fractions was established.Aromatic hydrocarbons in petroleum can be selectively converted into strong polar sulfonates through solid phase sulfonation reaction,silica sulfuric acid was used as the sulfonation agent.Aromatic sulfonates can be ionized by electrospray ionization,more importantly,these sulfonates of aromatic hydrocarbons with different condensation degrees had similar response factors.The method avoided the interference of saturated hydrocarbon compounds on the analysis of aromatic,and showed good quantitative analysis ability,which was far better than commercial atmospheric pressure photoionization method.The methodological basis for molecular characterization of saturated hydrocarbons in petroleum based on RICO reaction was improved.RICO reaction products of iso-paraffins and cycloparaffins are alcohols and ketones,but RICO reaction products of n-alkanes were mainly ketones.The molecular composition of iso-paraffins and cycloparaffins can be analyzed through alcohols originating from RICO products.Silica sulfuric acid was a much better agent than chlorosulfonic acid for the sulfonation reaction of aromatic hydrocarbons,which had better quantitative analysis ability.The molecular characterization method for hydrocarbons in heavy petroleum fractions showed good selectivity,alkyl and aryl groups could be effectively identified.The analysis methods of the molecular composition of hydrocarbons in heavy petroleum fraction combing with chemical derivatization and electrospray ionization mass spectrometry were combined with various analytical methods for other types of compounds.A scheme of semi-quantitative molecular characterization of heavy petroleum fractions was established,the electrospray ionization source was used as the only ionization technique.The molecular compositions of two heavy petroleum fractions with different bulk properties were analyzed.