Determination of Structural Building Blocks in Heavy Petroleum Systems by Collision-Induced Dissociation Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

Abstract

Collision-induced dissociation Fourier Transform ion cyclotron resonance mass spectrometry (CID-FTICR MS) was developed to determine structural building blocks in heavy petroleum systems. Model compounds with both single core and multicore configurations were synthesized to study the fragmentation pattern and response factors in the CID reactions. Dealkylation is found to be the most prevalent reaction pathway in the CID. Single core molecules exhibit primarily molecular weight reduction with no change in the total unsaturation of the molecule (or Z-number as in chemical formula C(c)H(2c+Z)N(n)S(s)O(o)VNi). On the other hand, molecules containing more than one aromatic core will decompose into the constituting single cores and consequently exhibit both molecular weight reduction and change in Z-numbers. Biaryl linkage, C(1) linkage, and aromatic sulfide linkage cannot be broken down by CID with lab collision energy up to 50 eV while C(2)+ alkyl linkages can be easily broken. Naphthenic ring-openings were observed in CID, leading to formation of olefinic structures. Heavy petroleum systems, such as vacuum resid (VR) fractions, were characterized by the CID technology. Both single-core and multicore structures were found in VR. The latter is more prevalent in higher aromatic ring classes.

Studying the fragmentation mechanism of selected components present in crude oil by collision‐induced dissociation mass spectrometry

“…Additionally, the loss of further fragments that differ in mass by multiples of 14 Da is observed. Following Qian et al, this could correspond to the loss of varying numbers of methylene units along the side chain, as depicted in Figure . Considering that the individual sulfur compounds present in the sample are likely to have an aromatic core structure, such as benzothiophene (BT), dibenzothiophene (DBT) or benzonaphthothiophene (BNT), among others, this would lead to the conclusion that besides the terminal CH 3 groups the side chains are cleaved at arbitrary positions with the loss of varying numbers of methylene units from fragment to fragment.…”

“…Some of those reports are the result of CID studies of synthesized compounds, albeit produced using synthetic methods that lead to a mixture of isomers. These might result in different fragmentation patterns and thus invalidate the interpretation of fragmentation mechanisms, as single fragments cannot be attributed to single isomers from the mixture …”

“…These might result in different fragmentation patterns and thus invalidate the interpretation of fragmentation mechanisms, as single fragments cannot be attributed to single isomers from the mixture. 26 Here, we report the synthesis and the study of the fragmentation behavior of different isomerically pure compounds that are considered to be present in a crude oil. For this study we focus on two types of compounds.…”

Core Structure Analysis of Heavy Oil Components with Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

“…This analysis revealed that both island and archipelago-type molecules were present in each aromatic ring fractions. Qian et al determined the typical aromatic building blocks contained in heavy petroleum fractions by FT-ICR MS with collision induced dissociation (CID) 12) . Their studies provided basic knowledge about the fragmentation of both island and archipelago-type molecules in CID analysis, indicating that the vacuum residue (VR) contains both island and archipelago-type structures.…”

Approach for Selective Separation of Thiophenic and Sulfidic Sulfur Compounds from Petroleum by Methylation/Demethylation

“…5,6 Characterization of sulfur compounds has been an important research topic in the petroleum community; 7−15 however, this issue has been challenging due to the complex hydrocarbon matrix and the inherent molecular complexity of sulfur compounds in heavy oils. 16,17 Separation of sulfur compounds from petroleum is critical for their multifaceted detailed characterization.…”