Studying Natural Buckyballs and Buckybowls in Fossil Materials

Abstract

Buckyballs (fullerenes) were first reported over 30 years ago, but still little is known regarding their natural occurrence, since they have so far only been found at sites of high‐energy incidents, such as lightning strikes or meteor impacts, but have not been reported in low‐energy materials like fossil fuels. Using ultrahigh‐resolution mass spectrometry, a wide range of fullerenes from C30 to C114 was detected in the asphaltene fraction of a heavy crude oil, together with their building blocks of C10nH10 stoichiometry. High‐level DLPNO‐CCSD(T) calculations corroborate their stability as spherical and hemispherical species. Interestingly, the maximum intensity of the fullerenes was found at C40 instead of the major fullerene C60. Hence, experimental evidence supported by calculations show the existence of not only buckyballs but also buckybowls as 3‐dimensional polyaromatic compounds in fossil materials.

Lessons Learned from a Decade-Long Assessment of Asphaltenes by Ultrahigh-Resolution Mass Spectrometry and Implications for Complex Mixture Analysis

“…In contrast, asphaltenes, which consist of ∼42 wt % of the entire sample, reveal a complementary compositional range to maltenes: with a similar carbon number range but a high relative abundance of species with DBE > 15 that are clustered close to the polycyclic aromatic hydrocarbon (PAH) limit. This compositional boundary (PAH limit) represents the highest possible DBE value, at a given carbon number, for planar/near planar petroleum molecules. − DBE values above this limit contain nonplanar aromatic cores (fullerene-like compounds) that are most likely absent in naturally occurring petroleum. , The analyzed asphaltenes required an accumulation period ∼40-fold longer than for maltenes (200 ms, MIY ≈ 5 ms –1 ); therefore, the characterization of the entire sample preferentially reveals maltenic compounds (despite containing ∼42 wt % asphaltenes), because asphaltenes are more difficult to ionize by APPI.…”

“…168−170 DBE values above this limit contain nonplanar aromatic cores (fullerene-like compounds) that are most likely absent in naturally occurring petroleum. 171,172 The analyzed asphaltenes required an accumulation period ∼40-fold longer than for maltenes (200 ms, MIY ≈ 5 ms −1 ); therefore, the characterization of the entire sample preferentially reveals maltenic compounds (despite containing ∼42 wt % asphaltenes), because asphaltenes are more difficult to ionize by APPI.…”

Understanding “Fouling” in Extremely Complex Petroleum Mixtures

“…The study of the chemical transformation of such complex mixtures with often more than one million different chemical compounds present needs special analytical tools. Here, ultra-high-resolution mass spectrometry − allows the analysis of the molecular changes of complex mixtures and as a very accurate analytical technique allows the calculation of elemental compositions from each detected signal. − For these studies, a research-type Orbitrap Elite was used that allows detailed and accurate coverage of complex samples and provides elemental compositions for a large number of signals …”

Study of Crude Oil Fouling from Sulfur-Containing Compounds Using High-Resolution Mass Spectrometry

“…One observation from the results is that the maximum DBE range here is below DBE 40. While we could show that it is possible to detect hydrocarbon type compounds up to DBE 100 34 and even after a fouling reaction it was shown that nitrogen compounds up to DBE 50 can be detected, 40 here the DBE of sulfur compounds remains comparably low. However, the ionization and the reactivity of the sulfurcontaining compounds depend on their structure.…”

“…Among them, gas chromatography/mass spectrometry (GC/MS) has been used to determine elemental sulfur in naphtha and gasoline, gel permeation chromatography (GPC) and ultrahigh resolution mass spectrometry have been successfully applied in the characterization of aromatic hydrocarbons and sulfur heterocycles in a heavy crude oil, while recently the analysis of three classes of sulfur compounds has been shown by using LC separation and an online detection and quantification by ICP-MS . High-resolution mass spectrometry (HRMS) is the method of choice for the investigation of complex mixtures due to its ability to provide high resolving power and highly accurate mass measurements. − Electrospray ionization (ESI) is not commonly selected for the ionization of polycyclic aromatic sulfur hydrocarbons (PASHs) since these species are typically not basic enough to be easily protonated and this method is often used for acidic types of compounds. − Thus, atmospheric pressure photoionization (APPI) is preferably used for their ionization. However, using chemical methods such as alkylation, we can achieve a selectivity toward sulfur-containing species, producing preformed ions and thus making their characterization by ESI possible .…”