scholarly journals Qualitative and Quantitative Analysis of Heavy Crude Oil Samples and Their SARA Fractions with 13C Nuclear Magnetic Resonance

Processes ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 995
Author(s):  
Ilfat Rakhmatullin ◽  
Sergey Efimov ◽  
Vladimir Tyurin ◽  
Marat Gafurov ◽  
Ameen Al-Muntaser ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Nmr Spectroscopy ◽  
Magnetic Resonance ◽  
Crude Oil ◽  
Functional Groups ◽  
13C Nmr ◽  
Nmr Spectra ◽  
13C Nmr Spectra ◽  
Sara Fractions ◽  
Nuclear Magnetic

Nuclear magnetic resonance (NMR) approaches have unique advantages in the analysis of crude oil because they are non-destructive and provide information on chemical functional groups. Nevertheless, the correctness and effectiveness of NMR techniques for determining saturates, aromatics, resins, and asphaltenes (SARA analysis) without oil fractioning are still not clear. In this work we compared the measurements and analysis of high-resolution 13C NMR spectra in B0 ≈ 16.5 T (NMR frequency of 175 MHz) with the results of SARA fractioning for four various heavy oil samples with viscosities ranging from 100 to 50,000 mPa·s. The presence of all major hydrocarbon components both in crude oil and in each of its fractions was established quantitatively using NMR spectroscopy. Contribution of SARA fractions in the aliphatic (10–60 ppm) and aromatic (110–160 ppm) areas of the 13C NMR spectra were identified. Quantitative fractions of aromatic molecules and oil functional groups were determined. Aromaticity factor and the mean length of the hydrocarbon chain were estimated. The obtained results show the feasibility of 13C NMR spectroscopy for the express analysis of oil from physical properties to the composition of functional groups to follow oil treatment processes.

scholarly journals Study of the biologically active acyclic ureas by nuclear magnetic resonance

2020 ◽  
Vol 100 (4) ◽  
pp. 60-74
Author(s):  
А.А. Bakibaev ◽  
◽  
М.Zh. Sadvakassova ◽  
V.S. Malkov ◽  
R.Sh. Еrkasov ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Functional Groups ◽  
13C Nmr ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Biologically Active ◽  
Resonance Spectroscopy ◽  
13C Nmr Spectra ◽  
Nuclear Magnetic

A wide variety of acyclic ureas comprising alkyl, arylalkyl, acyl, and aryl functional groups are investigated by nuclear magnetic resonance spectroscopy. In general, spectral characteristics of more than 130 substances based on acyclic ureas dissolved in deuterated dimethyl sulfoxide at room temperature are studied. The re-sults obtained based on the studies of 1H and 13C NMR spectra of urea and its N-alkyl-, N-arylalkyl-, N-aryl- and 1,3-diaryl derivatives are presented, and the effect of these functional groups on the chemical shifts in carbonyl and amide moieties in acyclic urea derivatives is discussed. An introduction of any type of substitu-ent (electron-withdrawing or electron-donating) into urea molecule is stated to result in a strong upfield shift in 13C NMR spectra relatively to unsubstituted urea. A strong sensitivity of NH protons to the presence of acyl and aryl groups in nuclear magnetic resonance spectra is pointed out. In some cases, qualitative depend-encies between the chemical shifts in the NMR spectra and the structure of the studied acyclic ureas are re-vealed. A summary of the results on chemical shifts in the NMR spectra of the investigated substances allows determining the ranges of chemical shift variations of the key protons and carbon atoms in acyclic ureas. The literature describing the synthesis procedures are provided. The results obtained significantly expand the methods of reliable identification of biologically active acyclic ureas and their metabolites that makes it promising to use NMR spectroscopy both in biochemistry and in clinical practice.

scholarly journals Organoarsenic probes to study proteins by NMR spectroscopy

2021 ◽  
Author(s):  
Mithun Mahawaththa ◽  
Henry Orton ◽  
Ibidolapo Adekoya ◽  
Thomas Huber ◽  
Gottfried Otting ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Nmr Spectroscopy ◽  
Magnetic Resonance ◽  
Nmr Spectra ◽  
Protein Nmr ◽  
Structural Studies ◽  
Pseudocontact Shifts ◽  
Paramagnetic Probes ◽  
Loop Regions ◽  
Nuclear Magnetic

Arsenical probes enable structural studies of proteins. We report the first organoarsenic probes for nuclear magnetic resonance (NMR) spectroscopy to study proteins in solutions. These probes can be attached to irregular loop regions. A lanthanide-binding tag induces sizable pseudocontact shifts in protein NMR spectra of a magnitude never observed for small paramagnetic probes before.

Characterization of Crude Oil Products Using Data Fusion of Process Raman, Infrared, and Nuclear Magnetic Resonance (NMR) Spectra

2011 ◽  
Vol 65 (2) ◽  
pp. 181-186 ◽  
Author(s):  
Thomas I. Dearing ◽  
Wesley J. Thompson ◽  
Carl E. Rechsteiner ◽  
Brian J. Marquardt
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Data Fusion ◽  
Crude Oil ◽  
Nmr Spectra ◽  
Oil Products ◽  
Using Data ◽  
Nuclear Magnetic
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