Structural Characterization of Unfractionated Asphalts by¹H NMR and¹³C NMR

Abstract

An improved methodology for the structural characterization of heavy fractions of petroleum by hydrogen-1 and carbon-13 nuclear magnetic resonance was applied to three fresh and unfractionated asphalts in solution. The results were compared with those generated by two other known characterization methods applied to the same NMR spectra. The comparison revealed inconsistencies in the traditional methods for the structural characterization of this type of materials. The improved methodology can be applied to unfractionated samples, and it provides a more detailed structural characterization of the asphalts than previously obtained. The new method provides a better correlation between physicochemical properties and the chemical structure of the complex mixtures of hydrocarbons.

Characterization of deasphalted heavy fuel oil using APPI (+) FT-ICR mass spectrometry and NMR spectroscopy

“…This indicates that benzothiophenes (DBE 6), dibenzothiophenes (DBE 9) and benzonaphthothiophenes (DBE 12) and their derivatives with alkyl side chains may be the most abundant PASH species [31] in both HFO and DAO. These PASH species exhibit carbon numbers up to 80, which shows the presence of long or multiple short alkyl chains connected to the rings [58,[67][68][69]. The high boiling range of these fuels is evident due to the presence of large DBE values (>20) which indicate the presence of tetra and penta aromatics [31,70].…”

Study of Thermal Aging of Model Compounds Present in Asphalt Cement by GC/MS, ESI-MS, NMR, and FTIR

“…Cardozo, Moreno, and Trujillo (2016) 15 improved a methodology for the structural characterization of heavy fractions of petroleum by 1 H and 13 C NMR on unfractionated asphalt samples and provided a better correlation between physicochemical properties and chemical structure of the complex mixtures. Siddiqui (2009) 16 evaluated the chemical changes by short-and long-term aging in the saturates, naphthenic aromatics, resins, and asphaltene fractions of an asphalt sample by 1 H and 13 C NMR.…”

Exploration of the Difference in Molecular Structure of n-C7 and CO2 Induced Asphaltenes

“…10,11 Particularly remarkable advances have been achieved in understanding asphaltene morphologies using scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM) techniques. 14 The past decade has also witnessed major achievements by NMR 12,13,15,16 and Fourier transform infrared (FTIR) 17 spectroscopies. These techniques have been used to determine the structure and composition of petroleum fractions including asphaltenes.…”

“…Recent developments in key analytical techniques, i.e., X-ray diffractometry (XRD), , NMR spectroscopy, , and electron microscopy, have continuously pushed the limits for studying challenging carbonaceous and high molecular weight assemblies such as asphaltenes. X-ray crystallography remains the primary tool for the determination of interlayer spacing, crystallite size, and crystallite diameter of asphaltenes, and major accomplishments have been reported in recent years. , Particularly remarkable advances have been achieved in understanding asphaltene morphologies using scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM) techniques .…”

“…X-ray crystallography remains the primary tool for the determination of interlayer spacing, crystallite size, and crystallite diameter of asphaltenes, and major accomplishments have been reported in recent years. , Particularly remarkable advances have been achieved in understanding asphaltene morphologies using scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM) techniques . The past decade has also witnessed major achievements by NMR ,,, and Fourier transform infrared (FTIR) spectroscopies. These techniques have been used to determine the structure and composition of petroleum fractions including asphaltenes.…”