Nitrogen release in the gasification of carbons

Grant, Ken; Zhu, Qian; Thomas, K. Mark

doi:10.1016/0008-6223(94)90045-0

Cited by 47 publications

(25 citation statements)

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“…Carbonization of polyvinylcarbazole at 600 and 900°C is accompanied by the minimal release of nitrogen-bearing volatile products (HCN and NH 3 ) by comparison with the other two polymers, from which it is concluded that there is preferential conversion of five-membered nitrogen rings into quaternary nitrogen compounds, which subsequently participate in the form of a labile structure preceding graphitization. This agrees with conclusions on the pyrolysis of coals and carbonaceous plant products containing nitrogen in various cyclic modifications [41,42], which confirms the genetic relation between coal formation from natural and synthetic high-molecular compounds. In these papers, thermochemical transformations of carbonaceous materials under identical conditions, namely ones based on lignin and synthetic carbonizates obtained from carbazole, acridine, and polyacrylonitrile.…”

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The role of nitrogen atoms in forming the carbon structure in the carbonization of polymer composites

2008

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Data have been used from X-ray photoelectron spectroscopy, small-angle X-ray spectroscopy, nuclear magnetic resonance, IR Fourier spectroscopy, electron spectroscopy, and other current methods for polyacrylonitrile, polypyromellitimide, hydrated cellulose, hard coals, and various model compounds to examine the effects of the nitrogen atoms on carbonization and graphitization. The nitrogen atoms are found to have multiple effects on the thermochemical and thermophysical parameters of the polymer carbonization over a wide temperature range. In the derivation of the carbon structures, the nitrogen acts as a messenger combined agent, which gives rise to heterorings, which are transformed into intermediate aromatic compounds, which form the basis of the matrix synthesis consisting of ordered graphite-type structures.Polymer carbonization is a thermochemical process with a long history. The first researches in this area were simultaneous with the determination of the macromolecular nature of coal.Analyses of hard coals with various degrees of metamorphism show that in addition to carbon they contain various heteroatoms, amongst which nitrogen and sulfur are counted fairly frequently no matter what the local origin of the coal. One trend in coal chemistry was research on thermal treatment, which alters the coal composition and structure. It alters the basic applied parameters of coal as a fuel. From the viewpoint of the chemistry and physics of macromolecular compounds, the changes occurring in coals involve thermophysical and thermochemical reactions. The multiplet composition found in coals means that these processes are inseparable and have effects on the composition and properties of the heat-treatment products. Numerous researches [1][2][3] have shown that competition between destruction and structuring determines the trend in thermochemical processes. The heating conditions determine whether the coal will burn almost completely up to a certain temperature and be converted to gaseous and readily volatile products from thermal and thermal-oxidative destruction. With special technologies, a hard coal can be converted to carbon-saturated products, from which carbon materials and components are formed that are used in many branches of industry.The transformations in the polymers forming the main part of a coal are dependent on many factors, amongst which a considerable part is played by the elemental and functional compositions. Accumulated analytical data for the area have enabled one to build up qualitative and quantitative pictures of the transformation of the constituent elements over wide temperature ranges. The data allow one to observe fairly novel properties of the nitrogen atoms: they are preserved in the carbonized products, whereas the atoms of hydrogen, oxygen, sulfur, and certain other elements almost completely leave the sphere of thermochemical reactions up to temperatures of 1000-1200°C. However, most researchers have not drawn any further conclusions from the unusual thermal stability of nitrogen in th...

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The role of nitrogen atoms in forming the carbon structure in the carbonization of polymer composites

2008

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“…4d). These peaks were assigned to; (i) pyridinic-N at 397.9-398.6 eV, with the N atom contributing one electron to the p-system, (ii) pyrrolic-N at 399.1-399.8 eV with the N atom contributing two electrons to the psystem, (iii) graphitic-N (400.9-400.9 eV) with the N atom substituting the C atom in the graphitic structure 37,71 and (iv) NO X due to oxygenation of pyridinic-N (>402 eV). 70,72,73 The NCSs-H 2 comprised of 48% pyridinic-N, 21% pyrrolic-N and 22% graphitic-N and 9% NO X .…”

Section: Xps Analysis Of the N-doped Cssmentioning

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Generation of radical species in CVD grown pristine and N-doped solid carbon spheres using H₂ and Ar as carrier gases

et al. 2017

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“…After Cagniant et al [21], ammoxidation of cellulosic material leads to fixation of 60% of nitrogen as imine which gives pyridinic nuclei, while the synthesis of pyrrolic nucleus occurs also by reaction of ammonia with dicarbonyl moieties. After Thomas et al [30,31], formation of pyrrolic, pyridinic and pyridine N-oxide functions at the edge and in the interior of the poly-aromatic systems (graphene layers) would depend on the isotropic/anisotropic character of the carbon and on the fact that the ammonia treatment is performed during or after carbonization.…”

Section: 2 Surface Groups Characterization After Modification With mentioning

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Adsorption of H2S or SO2 on an activated carbon cloth modified by ammonia treatment

Boudou

Chehimi

Broniek

et al. 2003

Carbon

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Nitrogen release in the gasification of carbons

Cited by 47 publications

References 8 publications

The role of nitrogen atoms in forming the carbon structure in the carbonization of polymer composites

The role of nitrogen atoms in forming the carbon structure in the carbonization of polymer composites

Generation of radical species in CVD grown pristine and N-doped solid carbon spheres using H₂ and Ar as carrier gases

Adsorption of H2S or SO2 on an activated carbon cloth modified by ammonia treatment

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Nitrogen release in the gasification of carbons

Cited by 47 publications

References 8 publications

The role of nitrogen atoms in forming the carbon structure in the carbonization of polymer composites

The role of nitrogen atoms in forming the carbon structure in the carbonization of polymer composites

Generation of radical species in CVD grown pristine and N-doped solid carbon spheres using H2 and Ar as carrier gases

Adsorption of H2S or SO2 on an activated carbon cloth modified by ammonia treatment

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Generation of radical species in CVD grown pristine and N-doped solid carbon spheres using H₂ and Ar as carrier gases