Characterization of Saturated Hydrocarbons in Vacuum Petroleum Residua: Redox Derivatization Followed by Negative-Ion Electrospray Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

Heavy petroleum fractions, which have distinct chemical and physical properties, are becoming important refinery feedstocks. In comparison to aromatic and heteroatom-containing compounds, the saturate compounds in heavy petroleum fractions have rarely been analyzed using recent advanced mass spectrometry methods. In this work, the compositions of saturate fractions derived from six vacuum residua (VR) of different geological origins were determined and compared. Saturate fractions were subjected to ruthenium-ion-catalyzed oxidation (RICO) derivatization and characterized with negative-ion electrospray ionization (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). The results showed that the VR-derived saturates consisted of n-paraffins, isoparaffins, and naphthenes with 1–10 rings. The maximum double bond equivalent (DBE) values of species in various VR-derived saturates were similar. The maximum carbon number of VR-derived saturates was up to 100. The maximum carbon numbers of ...