Characterization and Comparison of Nitrogen Compounds in Hydrotreated and Untreated Shale Oil by Electrospray Ionization (ESI) Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR MS)

Abstract

Shale oil has attracted more attention, as a very important substitutable fuel resource. In the present research, the classes and structures of nitrogen species in hydrotreated and untreated Fushun shale oil (FSO) are characterized by electrospray ionization (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). Experimental results have demonstrated that most of the nitrogen compounds in FSO are removed effectively during the hydrotreatment. N1 and N2 classes are dominant in FSO, and their structures are deduced in terms of the double bond equivalent (DBE) values and the Fourier transform infrared (FTIR) spectra. N1 class species in FSO are probably pyridines, indoles, carbazoles, benzocarbazoles, and their derivatives. After hydrotreating, the N1 class species in hydrotreated Fushun shale oil (HFSO) extend over a wider range of DBE values and carbon numbers than in the original FSO. It can be concluded that the N1 class species in HFSO are generated from compounds containing two or more heteroatoms, such as N2, N1O1, N1O2, N1O1S1, N1S1, and N2S1 class species.

Characterization of Basic Nitrogen-Containing Compounds in the Products of Lube Base Oil Processing by Electrospray Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

“…Among the basic nitrogen compounds N 1 , N 2 , N 1 O 1 , and N 1 O 2 identified by the positive-ion mass spectra from VGOs, the N 1 class species were the most abundant, and N 1 O 1 class species took the second place, which is similar to the results reported by other authors. 4,5,14 While N 1 O 2 class was not found from VGO cut-2, and N 2 class was only identified from VGO cut-4, indicating the complexity of the basic nitrogen compounds increased with the increasing of boiling point of subfractions. In dewaxed VGOs, the N 1 class was also the predominant one, and followed by N 1 O 1 class.…”

“…Wu et al 16 pointed out that the quantitative determination to all species identified is not currently The N 1 O 1 class species are likely be comprised of a pyridine ring and a furan ring or a double bond of carbon and oxygen. 5 While N 1 O 2 class species may be suggested more complex structures: a pyridine ring and two furan rings, or a pyridine ring, a furan ring and a double bond of carbon and oxygen, etc. And the N 2 class species are likely amphoteric molecules including two heterocyclic rings: a pyridine ring and a pyrrole ring, 5 were enriched in the heavy fraction.…”

“…5 While N 1 O 2 class species may be suggested more complex structures: a pyridine ring and two furan rings, or a pyridine ring, a furan ring and a double bond of carbon and oxygen, etc. And the N 2 class species are likely amphoteric molecules including two heterocyclic rings: a pyridine ring and a pyrrole ring, 5 were enriched in the heavy fraction. Generally, N 1 compounds are the most complex and predominant basic nitrogen compound, and there are almost no nitrogen compounds with a small number of carbons and low saturation.…”

“…Sample preparation method by positive-ion ESI FT-ICR MS has been previously reported. 2,5 The sample solution was infused via an Apollo II electrospray source at 180 L/h by a syringe pump. The operating conditions for positive-ion formation were 4.0 kV emitter voltage, 4.5 kV capillary column front end voltage, and 320 V capillary column end voltage.…”

“…However, GC-MS is not capable of analyzing samples that contain higher molecular-mass nitrogen compounds because of their low volatility. 2,5 Recently, Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) with an ultrahigh mass resolution and mass accuracy has been successfully used to analyze trace polar compounds found in petroleum systems at the molecular level. Positive-ion ESI can selectively ionize heteroatom species, such as basic nitrogen compounds, and negative-ion ESI can be used for acids and neutral nitrogen compounds.…”