Obtaining Nanoporous Polycyclic Aromatic Hydrocarbon Networks by Cross-Linking Asphaltenes

Abstract

The complexity in the chemical structure of asphaltenes has the potential to be utilized in generating novel materials. In the present study, three different asphaltene samples derived from heavy and light crude oils are cross-linked in a chlorinated solvent. Diffuse reflectance infrared Fourier transform spectroscopy was used for the identification of functional groups and aliphatic-to-aromatic ratios type index values of cross-linked asphaltenes. Raman spectra of asphaltenes showed an increase in average molecular dimensions of cross-linked asphaltenes compared to the original asphaltenes without cross-linking. A porous network-type structure is proposed for explaining the structure of the cross-linked asphaltenes, and this is revealed by surface area analysis. It seems that it is possible to cross-link asphaltenes independent of their geographical origin. The experimental procedure here could be applied for similar materials as well. The cross-linked asphaltenes with porous network-type structure might act as a precursor material for making activated porous carbons, a carbonaceous scaffold for synthesizing novel materials in the confined state, and for modifying surfaces of nanomaterials.

Petroleum Asphaltene-Based Activated Nanoporous Carbon for CO2 Capture and H2 Storage

“…34 The L a values of carbonized asphaltenes upon thermal treatment at 700 and 800 °C in the present study are closer to those of the chemically cross-linked asphaltenes. 18 The most remarkable point arises from comparing the current results to the ones in the literature on graphite, graphene oxide, and reduced graphene oxide. As seen in Figure 2, thermal treatment increased the intensity and caused a shift in the peak position of the D1 band.…”

“…In contrast, carbonization of asphaltenes yielded a decrease in I 3 for sample 3, only a slight increase in I 3 for sample 2, and a threefold increase in I 3 for sample 1. 18,27 Upon carbonization of asphaltenes, there is an increase in I 1 . In contrast, I 1 decreased upon thermal treatment and became closer to zero.…”

“…16,17 The richness in sp 2 -hybridization of carbon species and polycyclic aromatic hydrocarbons found in the chemical structures of asphaltenes ease the cross-linking of these molecules. 18,19 The development of porous carbon nanosheets with a certain level of graphitization obtained from asphaltenes, 2 a cheap and abundant by-product, 3 for mass production might have significance for both the environment and crude oil industry. 3 Several reports have explained the synthesis of nanoporous carbonized asphaltenes.…”

Addressing Thermal Behavior and Molecular Architecture of Asphaltenes by a Thermal-Optical Carbon Analyzer Coupled to High-Resolution Mass Spectrometry

“…In fossil petroleum refining, flow assurance is one of the common challenges due to deposit formation, flocculation, or catalyst poisoning. − As a key contribution to a variety of problems, the fraction of petroleum termed “asphaltenes” has been identified. − Asphaltenes are defined as n -pentane/ n -heptane insoluble fraction of crude oil likely containing high molecular weight, heteroatom-rich and highly aromatic compounds, which are prone to aggregation, and complex occlusion inter- and intramolecular interactions with other oil fractions. − Despite their problematic nature with regard to petroleum processing, asphaltenes are currently gaining importance in material sciences for the generation of carbon fibers . They also have potential as supercapacitors, , as novel materials when chemically modified, e.g., by cross-linking, or for liquid purification . Thus, utilizing fossil resources in material science will coincide with lowering the carbon dioxide emissions, while still being able to supply the global economy with affordable products.…”

“…14−16 Despite their problematic nature with regard to petroleum processing, asphaltenes are currently gaining importance in material sciences for the generation of carbon fibers. 17 They also have potential as supercapacitors, 18,19 as novel materials when chemically modified, e.g., by crosslinking, 20 or for liquid purification. 21 Thus, utilizing fossil resources in material science will coincide with lowering the carbon dioxide emissions, while still being able to supply the global economy with affordable products.…”