NMR-Spectrometric Determination of the Fragmented Oil Composition from the Karazhanbas and Zhangurshi Oil Deposits

The methods of 1 H, 13C NMR-spectroscopy were used to study the fragmentary compositions of oil from the Karazhanbas, Zhangurshi deposits (Kazakhstan) and heavy oil residues obtained before and after the electrohydraulic effect of water hammer after topping a light fraction of oil products. Their fragmentary composition were determined by the value of integrated intensities of 1 H, 13C NMR signals of the oil under study. The obtained results have shown that the composition of oil samples understudy includes terminal CH3-groups of long alkyl chains having a value of 0.87 ppm. The presence of long alkyl chains of oil components imparts a high viscosity and bituminous consistency to the latter. The content of aromatic protons according to the integrated intensities of 1 H NMR in both oil samples does not exceed 2.08%; but there are no aromatic nuclei by the integral intensities of carbon atoms at all. The low content of protons of Hα-type in hydrocarbon crude (5.2–5.3%) indicates a low content of aromatic and carbonyl carbons as well as heteroatoms in the studied samples. The content of the greater proportion of protons of the Hγ-type in Karazhanbas oil (33.0%) compared to the Zhangurshi oil (23.8%) indicates a greater length of aliphatic hydrocarbons of the latter and its increased viscosity.

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13C-NMR-Spektroskopie an polycyclischen Aromaten, II. Die 13C-NMR-Spektren von 1- und 2-Fluornaphthalin. Überprüfung der Signalzuordnung und Untersuchung der Substituenteneffekte auf die chemischen Verschiebungen / 13C NMR Spectroscopy of Polycyclic Aromatics, II. The 13C NMR Spectra of 1- and 2-Fluoronaphthalene. Reexamination of Signal Assignments and Investigation of Substituent Effects on Chemical Shifts

Zeitschrift für Naturforschung B ◽

10.1515/znb-1975-9-1026 ◽

1975 ◽

Vol 30 (9-10) ◽

pp. 788-793 ◽

Cited By ~ 14

Author(s):

Ludger Ernst

Keyword(s):

13C Nmr ◽

Nmr Spectra ◽

Chemical Shifts ◽

Double Resonance ◽

Substituent Effects ◽

13C Nmr Spectroscopy ◽

Polycyclic Aromatics ◽

H Nmr ◽

Iterative Analysis ◽

C Nmr

During a reinvestigation of the 13C NMR spectra of 1-fluoronaphthalene (1) and of 2-fluoronaphthalene (2) at 20 and 25.16 MHz, uncertainties that existed in the literature about signal assignments for 1 could be cleared. In the spectral analyses for 2 given so far, five out of ten signals were incorrectly assigned. The corrected assignment is supported by extensive 13C{1H} double resonance experiments, by recording of proton-coupled 13C and 13C{19F} spectra and by off-resonance 13C{1H} noise-decoupling. The results show a strong + M-effect of the fluorine substituents on 13C chemical shifts similar to the effects of OH and OCH3 groups. 1H NMR spectra of 1 and 2 could be partially assigned by decoupling of the 19F resonances and by iterative analysis.

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Investigation of Electrohydraulic Effect on Physicochemical Characteristics of High-Resinous Oil “Karazhanbas”

Eurasian Chemico-Technological Journal ◽

10.18321/ectj999 ◽

2020 ◽

Vol 22 (4) ◽

pp. 315

Author(s):

R.Kh. Salakhov ◽

M. Seitzhanova ◽

D.U. Bodykov ◽

L.R. Sassykova ◽

N.K. Zhakirova ◽

...

Keyword(s):

Heavy Oil ◽

Hydrocarbon Composition ◽

13C Nmr Spectroscopy ◽

Physicochemical Characteristics ◽

High Viscosity ◽

Fragment Composition ◽

Oil Hydrocarbons ◽

Oil Fractions ◽

Before And After ◽

High Viscosity Oil

In order to change the viscosity of high-resinous oil of the “Karazhanbas” field (Kazakhstan), the effect of electrohydraulic action on it was studied. The effect of adding an organic solvent xylene on the rheological properties of oil is investigated. A comparative study of the hydrocarbon composition of oil before and after electrohydraulic impact was carried out by the method of gas chromatographymass spectrometry. Fragment composition of oil hydrocarbons before and after electrohydraulic treatment was determined by 1H and 13C NMR spectroscopy. It is shown that the conversion of heavy oil fractions to light ones begins with a five-time electrohydraulic impact. It is determined that 20‒25 electric discharge pulses are sufficient for the quantitative process of splitting hydrocarbons. It was found that the addition of xylene to high-viscosity oil leads to an increase in the conversion of hydrocarbons under electrohydraulic action. The content of paraffins and naphthalenes in high-viscosity oil is slightly reduced during electrohydraulic processing. In oil, after electrohydraulic action, a decrease in the proportion of protons of long alkyl terminal СН3-groups of hydrocarbons is observed, which indicates the process of decomposition of heavy oil fractions into light fractions.

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Isolierungen und 11C-NMR-Spektroskopie von Indoleninalkaloiden / Isolation and 13C NMR Spectroscopy of Indolenine Alkaloids

Zeitschrift für Naturforschung B ◽

10.1515/znb-1982-0417 ◽

1982 ◽

Vol 37 (4) ◽

pp. 494-498 ◽

Cited By ~ 12

Author(s):

Mohammad Ataullah Khan ◽

Hans Horn ◽

Wolfgang Voelter

Keyword(s):

Nmr Spectroscopy ◽

13C Nmr ◽

Nmr Spectra ◽

13C Nmr Spectroscopy ◽

H Nmr ◽

First Time

The indolenine alkaloids raucaffricine and perakine were isolated from Rauwolfia caffra Sonder and their PFT 13C{1H}-NMR spectra studied for the first time. The interpretations of their spectra were accomplished in correlating with those of quinuclidine, indole, methyl-α-D-galactopyranoside, methyl-β-D-galactopyranoside, methyl-2,6-di-O-methyl-α-D-galactopyranoside and methyl-3-O-methyl-β-D-galactopyranoside.

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2D Solid-State HETCOR 1H-13C NMR Experiments with Variable Cross Polarization Times as a Tool for a Better Understanding of the Chemistry of Cellulose-Based Pyrochars—A Tutorial

Applied Sciences ◽

10.3390/app11188569 ◽

2021 ◽

Vol 11 (18) ◽

pp. 8569

Author(s):

Heike Knicker ◽

Marta Velasco-Molina ◽

Michael Knicker

Keyword(s):

Solid State ◽

13C Nmr ◽

Contact Time ◽

Chemical Nature ◽

13C Nmr Spectroscopy ◽

Variable Cross ◽

Cross Polarization ◽

Alkyl Chains ◽

Protonation Degree

The chemistry and nature of biochars are still far from being well understood. In the present work, solid-state 2D HETCOR 1H-13C NMR spectroscopy is introduced for an improved characterization of the aromatic network in biochars. To that end, a pyrochar obtained from the pyrolysis of cellulose at 350 °C for 1 h was used as an example. Variation of the contact time during cross polarization from 50 µs, to 200 µs and 1000 µs gave information about the protonation degree of the different C groups and their interactions. We demonstrated that carbohydrates did not survive the used pyrolysis conditions. Therefore, O-alkyl C was assigned to ethers. Phenols were not identified to a higher extent suggesting that furan and benzofuran-type units determine the O-functionality of the aromatic domains. The latter are directly connected to alkyl chains. Those features are expected to affect chemical but also physical properties of the biochar. Based on our results, we developed a new concept describing the nature of the aromatic network in the studied cellulose-based pyrochars. The latter contrasts common views about the chemical nature of biochar, possibly because pyrolysis temperatures > 350 °C are required for achieving advanced condensation of the aromatic domains.

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DETERMINATION OF CHEMICAL STRUCTURE OF METHYL HYDROXYETHYLCELLULOSE BY 13C NMR SPECTROSCOPY

IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENIY KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA ◽

10.6060/ivkkt.20196208.5910 ◽

2019 ◽

Vol 62 (8) ◽

pp. 102-112

Author(s):

Sergey G. Kostryukov ◽

Sergey V. Araslankin ◽

Pavel S. Petrov ◽

Valentin A. Kalyazin ◽

Angam Adil Ismail Al-Rubaye

Keyword(s):

Nmr Spectroscopy ◽

13C Nmr ◽

Program Analysis ◽

Chemical Structure ◽

Chemical Shifts ◽

Structural Parameters ◽

13C Nmr Spectroscopy ◽

Degree Of Substitution ◽

Integrated Intensities

This paper discusses the determination of the structural parameters of methyl hydroxyethylcellulose (MHEC) by 13C NMR spectroscopy. Four samples of methyl hydroxyethylcellulose (MHEC, DS ~ 1.7) of different viscosity aqueous solutions were analyzed to determine the distribution of methyl and hydroxyethyl groups in different positions of the anhydroglucose unit of the polymer chain. For this purpose, MHEC samples were subjected to acid-catalyzed hydrolysis in the presence of sulfuric acid. Optimal conditions for complete hydrolysis leading to methyl and hydroxyethyl substituted D-glucose derivatives were determined. The structure of the hydrolysis products was studied by 13С NMR spectroscopy. The assignment of carbon atom signals in the 13С NMR spectra was made based on chemical shifts calculated using BIOPSEL program. Analysis of the integrated intensities of the C-atom groups of the products of hydrolysis allowed us to determine the distribution of substituents in the anhydroglucose unit. The values of the degree of substitution in 2, 3 and 6 positions (DSC-2, DSC-3 и DSC-6) are calculated, the number of methoxyl (DSMe) and hydroxyethoxyl (DSHE) groups is determined, the total degree of substitution (DStotal) is calculated. The distribution of substituents in different positions of the glucopyranose unit indicates the highest reactivity of 2 and 6 positions, as well as hydroxyl in the hydroxyethyl group. In this paper, the degree of substitution in four different MHEC samples with known DS values is determined. Comparative analysis of the results obtained with the data specified by the manufacturer confirms the high accuracy of the considered method. The proposed method for determining the chemical structure of MHEC is informative since the method allows determining the distribution of substituents for different positions of the anhydroglucose unit and the degree of substitution of each substituent.

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(2S,3R,6R)-2-[(R)-1-Hydroxyallyl]-4,4-dimethoxy-6-methyltetrahydro-2H-pyran-3-ol

Molbank ◽

10.3390/m1140 ◽

2020 ◽

Vol 2020 (2) ◽

pp. M1140

Author(s):

Jack Bennett ◽

Paul Murphy

Keyword(s):

Mass Spectrometry ◽

Nmr Spectroscopy ◽

Ir Spectroscopy ◽

13C Nmr ◽

Conjugate Addition ◽

13C Nmr Spectroscopy ◽

One Pot ◽

1H And 13C Nmr ◽

Esi Mass Spectrometry ◽

The One

(2S,3R,6R)-2-[(R)-1-Hydroxyallyl]-4,4-dimethoxy-6-methyltetrahydro-2H-pyran-3-ol was isolated in 18% after treating the glucose derived (5R,6S,7R)-5,6,7-tris[(triethylsilyl)oxy]nona-1,8-dien-4-one with (1S)-(+)-10-camphorsulfonic acid (CSA). The one-pot formation of the title compound involved triethylsilyl (TES) removal, alkene isomerization, intramolecular conjugate addition and ketal formation. The compound was characterized by 1H and 13C NMR spectroscopy, ESI mass spectrometry and IR spectroscopy. NMR spectroscopy was used to establish the product structure, including the conformation of its tetrahydropyran ring.

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