Solid state 13C NMR studies of selected oil shales from Queensland, Australia

Miknis, Francis P.; Lindner, A. W.; Gannon, A.John; Davis, Mark F.; Maciel, Gary E.

doi:10.1016/0146-6380(84)90120-7

Cited by 25 publications

(5 citation statements)

References 13 publications

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“…The kerogen and the olivine powder were mixed at a ratio of 200.5 mg/800.9 mg (V or /V sil = 0.65) as a starting material. Type III kerogen shows C/H molar ratio and 13 C-NMR spectrum similar to those of IOM in the Murchison meteorite (Miknis et al 1984;Cronin et al 1987). Kerogen of low volatile bituminous coal may, however, be more suitable for an analogue of IOM in the Murchison meteorite compared with the type III kerogen of semianthracite (Sephton et al 2004a).…”

Section: Type III Kerogenmentioning

confidence: 87%

Selective release of D and ¹³C from insoluble organic matter of the Murchison meteorite by impact shock

Mimura

Okamoto

Sugitani

et al. 2007

Meteorit & Planetary Scien

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Abstract-We performed shock-recovery experiments on insoluble organic matter (IOM) purified from the Murchison meteorite, and determined the abundances and isotope ratios of hydrogen and carbon in the shocked IOM sample. We also performed shock experiments on type III kerogen and compared the results of these experiments with the experimental results regarding IOM.The shock selectively released D and 13 C from the IOM, while it preferably released H and 12 C from the kerogen. The release of these elements from IOM cannot be explained in terms of the isotope effect, whereas their release from kerogen can be explained by this effect. The selective release of heavier isotopes from IOM would be due to its structure, in which D and 13 C-enriched parts are present as an inhomogeneity and are weakly attached to the main network. Shock gave rise to a high release of D even at a lower degree of dehydrogenation compared with the stepwise heating of IOM. This effective release of D is probably an inherent result of shock, in which a dynamic highpressure and high-temperature condition prevails. Thus, shock would effectively control the hydrogen isotope behavior of extraterrestrial organic matter during the evolution of the solar nebula.

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Section: Type III Kerogenmentioning

confidence: 87%

Selective release of D and ¹³C from insoluble organic matter of the Murchison meteorite by impact shock

Mimura

Okamoto

Sugitani

et al. 2007

Meteorit & Planetary Scien

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“…According to the van Krevelen diagram, kerogen can be classified into four types on the basis of their ratios of H/C and O/C. In the past 2 decades, much efforts have been devoted to study kerogen, focusing on the research of the molecular structure, − kerogen pyrolysis, − and natural oil generation. − The chemical structure features of kerogen are of great practical significance to understand the pyrolysis mechanism and guide the actual industrial processes.…”

Section: Introductionmentioning

confidence: 99%

Three-Dimensional Structure of a Huadian Oil Shale Kerogen Model: An Experimental and Theoretical Study

et al. 2015

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The molecular structural information on a kerogen isolated from Huadian oil shale was obtained using solid-state 13 C nuclear magnetic resonance (NMR), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR), and X-ray diffraction (XRD) techniques. Then, a series of Huadian kerogen isomers were constructed on the basis of these structural data. The possible carbon skeleton isomer and the substituted position effects of the aromatic ring, aliphatic ether bond, carboxylic acid, and carboxylic acid derivative as well as the quantity of tertiary and quaternary carbons on Huadian kerogen model stability have been systematically studied on the basis of density functional theory (DFT) calculations. For the carbon skeleton isomer, the calculated total energy decreases with the increasing number of the closed annular space (grid), which is constituted by connecting the aliphatic chain to the aromatic cluster or other aliphatic chain. DFT calculations show an about 16.8 kcal mol −1 decrease in total energy for every grid increase when the number of grids increases from 2 to 11. A significant break in the decrease of the total energy has been obtained for an isomer with 11 grids, which means that a proper number of grids (11 grids is appropriate in this paper) in carbon skeleton should be considered for building the chemical structure of Huadian kerogen. For the substituted position effects, aliphatic ether bonding to quaternary carbon, carboxylic acid attaching to secondary carbon, and carboxylic acid derivative bonding to quaternary carbon seem to give a lower energy structure than other connections. Besides, a high quantity of tertiary and quaternary carbons is conducive to a stable model for Huadian kerogen. The aromatic cluster dispersed distribution also makes a contribution to improve the stability of the model. According to these results, we proposed a relatively stable Huadian kerogen three-dimensional (3D) model. Moreover, this 3D model was testified reasonablely through the match between calculated and experimental 13 C NMR spectra.

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“…The 13 C NMR spectra can be divided into three main regions: aliphatic carbons (0–90 ppm), aromatic carbons (90–170 ppm), and carbonyl carbons (170–220 ppm) . Peak fitting spectra of 13 C NMR was broadly used to study various types of carbon and their contents. − The chemical shifts of different carbons in 13 C NMR were determined according to the literature, − and they are shown in Table S1 in the Supporting Information.…”

Section: Results and Discussionmentioning

confidence: 99%

Production of Benzene Carboxylic Acids and Small-Molecule Fatty Acids from Lignite by Two-Stage Alkali-Oxygen Oxidation

Hou

Yang

et al. 2017

Ind. Eng. Chem. Res.

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Carboxylic acids are widely used in industry as a kind of important chemical materials, and it is very promising to produce carboxylic acids from lignite. The traditional alkalioxygen oxidation of lignite does not consider the complex structure of lignite, and the structures with different reactivities are treated under identical and harsh reaction conditions, resulting in a low yield of carboxylic acids. We propose a twostage oxidation process of lignite to increase the yield and mitigate the harsh reaction conditions. First, lignite was extracted using a NaOH aqueous solution to yield two parts (extract and residue) with different reactivities. The extract and residue then were oxidized separately with alkali-oxygen oxidation under different conditions. In this way, high yields of benzene carboxylic acids (BCAs, 12 types) and small-molecule fatty acids (SMFAs) could be obtained. The extraction conditions and the alkali-oxygen oxidation conditions of the extract and the residue were investigated. Compared with the oxidation of extract, the oxidation of residue requires higher reaction temperature, higher initial O 2 pressure, higher alkali concentration, and longer reaction time. The structures of the extract and residue were characterized by 13 C nuclear magnetic resonance ( 13 C NMR) and Fourier transform infrared (FT-IR) spectroscopy, which indicates that most of aromatic structures in the extract are single aromatic rings with side chains containing many oxygen-containing functional groups. However, aromatic structures in the residue are mainly condensed aromatic rings with side chains containing many alkyl chains. These differences in their structures result in different yields of carboxylic acids from the extract and residue.

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Solid state 13C NMR studies of selected oil shales from Queensland, Australia

Cited by 25 publications

References 13 publications

Selective release of D and ¹³C from insoluble organic matter of the Murchison meteorite by impact shock

Selective release of D and ¹³C from insoluble organic matter of the Murchison meteorite by impact shock

Three-Dimensional Structure of a Huadian Oil Shale Kerogen Model: An Experimental and Theoretical Study

Production of Benzene Carboxylic Acids and Small-Molecule Fatty Acids from Lignite by Two-Stage Alkali-Oxygen Oxidation

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Solid state 13C NMR studies of selected oil shales from Queensland, Australia

Cited by 25 publications

References 13 publications

Selective release of D and 13C from insoluble organic matter of the Murchison meteorite by impact shock

Selective release of D and 13C from insoluble organic matter of the Murchison meteorite by impact shock

Three-Dimensional Structure of a Huadian Oil Shale Kerogen Model: An Experimental and Theoretical Study

Production of Benzene Carboxylic Acids and Small-Molecule Fatty Acids from Lignite by Two-Stage Alkali-Oxygen Oxidation

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Product

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Selective release of D and ¹³C from insoluble organic matter of the Murchison meteorite by impact shock

Selective release of D and ¹³C from insoluble organic matter of the Murchison meteorite by impact shock