Multistage reduction of coals in the potassium/liquid ammonia system

Wachowska, Helena; Kozłowski, Mieczysław

doi:10.1016/0016-2361(95)00092-j

Cited by 12 publications

(7 citation statements)

References 12 publications

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“…As follows from our earlier works, , the multiple processes run in the potassium/liquid ammonia system cause deeper transformations in the coal structure than the processes run only once. That is why the effect of repeating the process on the sulfur compounds in coal is also investigated in this study.…”

Section: Introductionmentioning

confidence: 60%

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Atmospheric-Pressure Temperature-Programmed Reduction Study of High-Sulfur Coals Reduced in a Potassium/Liquid Ammonia System

Kozłowski¹,

Wachowska²,

Yperman³

et al. 1998

Energy Fuels

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Two high-sulfur coals have been subjected to an atmospheric-pressure temperature-programmed reduction study (AP-TPR). The studies were performed on both raw and potassium/liquid ammonia reduced samples. The reduction of coals in the potassium/liquid ammonia system was shown to induce conversion of sulfide and disulfide groups into thiol groups. AP-TPR studies performed with addition of the reducing mixture provided evidence for the presence of different types of thiols. The possibility of cleavage of the C-S bonds in thiophenes was indicated. A favorable effect of the reducing mixture on sulfur recovery was observed in the AP-TPR method, while the calcium compounds occurring in coal were found to be responsible for significant deformation of the kinetograms obtained. The effect of extraction with dichloromethane on sulfur compounds in coal was established, leading to a supposition of sulfur being mainly bonded with the macromolecular part of coal.

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Section: Introductionmentioning

confidence: 60%

“…Reduction of coals in the potassium/liquid ammonia system leads to an increase in their solubility in organic solvents . A detailed analysis of the soluble components gives important information on the coal structure.…”

Section: Resultsmentioning

confidence: 99%

Atmospheric-Pressure Temperature-Programmed Reduction Study of High-Sulfur Coals Reduced in a Potassium/Liquid Ammonia System

Kozłowski¹,

Wachowska²,

Yperman³

et al. 1998

Energy Fuels

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“…The adsorption of ammonia takes place during reduction [16] and the content of nitrogen increases. The original sulphur compounds in coal are diluted by introduction of methyl substitutes which leads to the decline of sulphur content [19,20]. Similar eects in changes of …”

Section: Resultsmentioning

confidence: 98%

Groups of Paramagnetic Centres in Reduced and Methylated Low Rank Coal

et al. 2015

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Low rank Illinois No. 6 coal was studied by electron paramagnetic resonance EPR spectroscopy. The parameters of EPR spectra (spectroscopic splitting factors g, linewidths ∆Bpp, concentrations of paramagnetic centres N ) were measured for row and chemically treated coal (demineralized, reduced and methylated samples). The multicomponent structure of experimental spectra of this coal was proved. Two groups of paramagnetic centres responsible for broad Lorentzian 1 and narrow Lorentzian 2 lines exist in studied samples. Paramagnetic centres connected with component lines revealed dierent behaviour during chemical treatments.

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“…8 The solubility of reduced anthracite was also found to be greater than that of the starting anthracite. 7 Atomic force microscopy (AFM). Atomic force microscopy (AFM) provides a way to determine the three-dimensional surface profile of a sample.…”

Section: Resultsmentioning

confidence: 99%

Reductive Alkylation of Anthracite: Edge Functionalization

et al. 2011

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Reduction of anthracite by electron transfer from either lithium or sodium in liquid ammonia yields a salt that can be alkylated by 1-iodododecane to yield nanocoal that is partially soluble in common organic solvents. NMR indicates that the dodecyl groups are attached to the edges of the aromatic ring systems, with many of the dodecyl groups extending into void spaces. Thermal gravimetric analysis shows that sodium gives a slightly higher level of functionalization. Atomic force microscopy (AFM) images of soluble dodecylated anthracite reveal nanoparticles that vary from 3 to 12 nm high. Scanning electron microscopy (SEM) and bright field high-resolution transmission electron microscopy (HRTEM) of the raw anthracite reveal a layered structure with dislocations. Inorganic materials that occur in the raw anthracite were identified by energy dispersive X-ray spectroscopy (EDS). Simple alkenes were found to react with the coal salt to give oligomers of the alkene that are grafted onto the surface of the coal.

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Multistage reduction of coals in the potassium/liquid ammonia system

Cited by 12 publications

References 12 publications

Atmospheric-Pressure Temperature-Programmed Reduction Study of High-Sulfur Coals Reduced in a Potassium/Liquid Ammonia System

Atmospheric-Pressure Temperature-Programmed Reduction Study of High-Sulfur Coals Reduced in a Potassium/Liquid Ammonia System

Groups of Paramagnetic Centres in Reduced and Methylated Low Rank Coal

Reductive Alkylation of Anthracite: Edge Functionalization

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