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Rüger, C.P.* ; Neumann, A.* ; Chacón-Patiño, M.L.* ; Rodgers, R.P.* ; Zimmermann, R.

Investigation of island/single-core- And archipelago/multicore-enriched asphaltenes and their solubility fractions by thermal analysis coupled with high-resolution Fourier transform ion cyclotron resonance mass spectrometry.

Energy Fuels 35, 3808-3824 (2021)
DOI
Open Access Green as soon as Postprint is submitted to ZB.
Despite extensive research, the molecular-level chemical characterization of asphaltenes, a highly aromatic solubility fraction of petroleum, remains an analytical challenge. This fraction is related to diverse problems in crude oil exploration, transportation, and refining. Two asphaltene architecture motifs are commonly discussed in the literature, “island” (single-core)- and “archipelago” (multicore)-type structures. The thermal desorption and pyrolysis behavior of island- and archipelago-enriched asphaltenes and their extrography fractions was investigated. For this purpose, the evolved chemical pattern was investigated by thermal analysis coupled with ultrahigh-resolution mass spectrometry (Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS)). Soft atmospheric pressure chemical ionization preserved the molecular information of the thermal emission profile. Time-/temperature-resolved analysis allowed the chemical characterization of the occluded material as well as of asphaltene building blocks during pyrolysis. Regarding the thermogravimetric information, the island-type enriched sample (Wyoming asphaltenes) revealed a significantly higher coke residue after the pyrolysis process compared to the archipelago-type enriched sample (Athabasca asphaltenes). In contrast to whole asphaltenes, extrographic fractions revealed that occluded material evolved during the desorption phase. For the acetone fraction, this effect was the most abundant and suggests cooperative aggregation, which persists at high temperatures. Pyrolysis revealed a bimodal behavior for most of the compound classes, suggesting the presence of both architecture motifs in each asphaltene. double-bond equivalent (DBE) vs #C diagrams of the pyrolysis molecular profile revealed specific compositional trends: compounds with high DBE values and short alkylation are likely to be originated from island-type asphaltenes, whereas species with low DBE values and high carbon numbers likely derive from archipelago-type asphaltenes. In the asphaltene structural debate, thermal analysis ultrahigh-resolution mass spectrometry serves as an additional technique and supplements results obtained by other techniques, such as direct infusion approaches. Consistent results on the structural motifs are indicated by the molecular fingerprint visualized by DBE vs #C diagrams and serve as a measure for the dominance of a structural motif.
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Publication type Article: Journal article
Document type Scientific Article
Corresponding Author
ISSN (print) / ISBN 0887-0624
e-ISSN 1520-5029
Journal Energy & Fuels
Quellenangaben Volume: 35, Issue: 5, Pages: 3808-3824 Article Number: , Supplement: ,
Publisher American Chemical Society (ACS)
Publishing Place 1155 16th St, Nw, Washington, Dc 20036 Usa
Non-patent literature Publications
Reviewing status Peer reviewed
Institute(s) Cooperation Group Comprehensive Molecular Analytics (CMA)
Grants German Research Foundation (DFG)
Horizon 2020 program
State of Florida
National Science Foundation Division of Chemistry