Journal ArticleDOI
Elucidation of structural and hydroliquefaction characteristics of Yallourn brown coal by carbon-13 CP/MAS n.m.r. spectrometry
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In this article, the chemical structure and hydroliquefaction characteristics of oxygen-rich Yallourn brown coal were investigated, and the structural parameters (fa, f' a, and H aru C ar ) were derived from spectral data.About:
This article is published in Fuel.The article was published on 1982-09-01. It has received 66 citations till now. The article focuses on the topics: Coal & Diphenyl ether.read more
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Book ChapterDOI
An Essay on the Organic Geochemistry of Coal
Abstract: Publisher Summary It is the geoscience of coals, that is, their geochemistry of origin and postburial geological history, that suggests that coals are a very diverse set of materials. This chapter discusses the relations between the chemistry of coal macerals and reviews the biochemistry of their precursors and the biological markers in coals that are indicative of their origins. The content of carboxyl groups in coals is commonly determined by an ion-exchange reaction with barium acetate. Values of 1–4 milliequivalents per gram have been found for lignites and lower-rank subbituminous coals—decreasing with increasing rank and essentially zero for coals of higher rank—except that HVC coals of the Rocky Mountain province may contain some carboxyl. The cations in the carboxylates of low-rank coals can give rise to calcite deposits in liquefaction reactors, can promote liquefaction, and can give rise to catalysts for the gasification of lignite chars.
Journal ArticleDOI
Analysis of oxygen-functional groups in brown coals
TL;DR: In this article, the distribution of oxygen-functional groups (alcohol, phenol, carboxyl, carbonyl, and ether groups) in four brown coals, Australian Yallourn (abbreviated as YL), Indonesian South Banko (SB) and Adaro (AD), and US Beulah Zap (BZ), was evaluated based on chemical analysis and 13 C NMR measurement.
Journal ArticleDOI
Preparation of carbon fibers with excellent mechanical properties from isotropic pitches
Byung Jun Kim,Youngho Eom,Osamu Kato,Jin Miyawaki,Byoung Chul Kim,Isao Mochida,Seong Ho Yoon +6 more
TL;DR: In this paper, a novel isotropic pitch composed of linear methylene chains of polycondensed aromatic molecules was synthesized from naphtha-cracked oil through bromination and subsequent dehydrobromination (NB).
Journal ArticleDOI
Compositional and solid-state nuclear magnetic resonance study of humic and fulvic acid fractions of soil organic matter
TL;DR: In this article, four soil organic matter samples (two humic acid fractions and two fulvic acid fractions) were obtained from two proximate soils in the flood plain of the Altamaha River in south-eastern Georgia.
Journal ArticleDOI
Enhancing the tensile strength of isotropic pitch-based carbon fibers by improving the stabilization and carbonization properties of precursor pitch
Byung Jun Kim,Toru Kotegawa,Youngho Eom,Jung-Chul An,Ik Pyo Hong,Osamu Kato,Koji Nakabayashi,Jin Miyawaki,Byoung Chul Kim,Isao Mochida,Seong Ho Yoon +10 more
TL;DR: In this article, a unique isotropic pitch composed of linear chains of polycondensed aromatic molecules was synthesized through the bromination and subsequent dehydrobromination of mixed naphtha-cracked oil (NCO) and quinoline-insoluble free coal tar (CT).
References
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Journal ArticleDOI
Proton‐enhanced NMR of dilute spins in solids
TL;DR: In this article, the NMR signals of isotopically or chemically dilute nuclear spins S in solids can be enhanced by repeatedly transferring polarization from a more abundant species I of high abundance (usually protons) to which they are coupled.
Journal ArticleDOI
Estimation of coal aromaticities by proton-decoupled carbon-13 magnetic resonance spectra of whole coals
TL;DR: In this paper, a cross-polarization technique was applied to obtain high-resolution carbon-13 spectra of vitrains from two coals, which overcomes the problem of dipolar line broadening by protons, permits estimates of the carbon aromaticities of solid coals.
Journal ArticleDOI
Characterization of organic material in coal by proton-decoupled 13C nuclear magnetic resonance with magic-angle spinning
TL;DR: In this article, the authors used high-power proton decoupling, cross polarization and magic-angle spinning to obtain the carbon distribution between aromatic and non-aromatic structures in coal samples.
Journal ArticleDOI
Prospects for carbon-13 nuclear magnetic resonance analysis of solid fossil-fuel materials
TL;DR: In this paper, it is shown that cross-polarization spectra obtained with dipolar decoupling display chemical shift anisotropy which interferes with attempts to distinguish the resonances of aromatic and aliphatic carbons.
Related Papers (5)
Estimation of coal aromaticities by proton-decoupled carbon-13 magnetic resonance spectra of whole coals
Evaluation of the quantitative reliability of the 13C CP/MAS technique for the analysis of coals and related materials
R. L. Dudley,Colin A. Fyfe +1 more