Change of chemical bonding of nitrogen of polymeric N-heterocyclic compounds during pyrolysis

Schmiers, Helmut; Friebel, Judith Miriam; Streubel, P.; Hesse, R.; Köpsel, Ralf

doi:10.1016/s0008-6223(99)00071-8

Cited by 237 publications

(139 citation statements)

References 18 publications

Supporting

Mentioning

134

Contrasting

Order By: Relevance

“…The first peak represents nitrogen involved in C-N (from amines or amides), whereas the second peak can be 9 assigned to C-N + (from quaternary nitrogen) or NH 4 + . [42][43][44] All of this indicates that ammonia is converted into new compounds strongly retained on the surface of GO or is incorporated to it via reactive adsorption/chemisorption. This is a very promising finding since one of the objectives to reach in efficient filtration is to prevent the gradual release of ammonia after its adsorption.…”

Section: Resultsmentioning

confidence: 99%

Revisiting the chemistry of graphite oxides and its effect on ammonia adsorption

2009

View full text Add to dashboard Cite

Graphical content entryThe mechanism of ammonia adsorption on graphite oxide (GO) is strongly related to the GO preparation and chemical features, especially to the sulfur-containing groups present on its surface. SummaryGraphite oxide (GO) was synthesized using two different methods: one with sulfuric acid as part of the oxidizing mixture (Hummers-Offeman method), and another one without the sulfurcontaining compound involved in the oxidation process (Brodie method). They were both tested for ammonia adsorption in dynamic conditions, at ambient temperature, and characterized before 2 and after exposure to ammonia by X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, potentiometric titration, energy-dispersive X-ray (EDX) spectroscopy, X-ray photoelectron spectroscopy (XPS) and elemental analysis. Analyses of the initial materials showed that besides epoxy, hydroxyl and carboxylic groups, a significant amount of sulfur is incorporated as sulfonic group for GO prepared by the Hummers-Offeman method. The process of ammonia adsorption seems to be strongly related to the type of GO. For GO prepared by the Brodie method, ammonia is mainly retained via intercalation in the interlayer space of GO and by reaction with the carboxylic groups present at the edges of the graphene layers. On the contrary, when GO prepared by the Hummers method is used, ways of retention are different: not only does the intercalation of ammonia is observed but also its reaction with the epoxy, carboxylic and sulfonic groups present. In particular, during the ammonia adsorption process, sulfonic groups are converted to sulfates in presence of superoxide anions O 2 -* . These sulfates can then react with ammonia to form ammonium sulfates. For both GOs, an incorporation of a significant part of the ammonia adsorbed as amines in their structure is observed as a result of reactive adsorption.

show abstract

Section: Resultsmentioning

confidence: 99%

Revisiting the chemistry of graphite oxides and its effect on ammonia adsorption

2009

View full text Add to dashboard Cite

show abstract

“…The N 1s core level spectrum of N-CNT2 is deconvoluted in Figure 2. Two main contributions are identified at 398.3 and 400.8 eV, which correspond respectively to pyridinic-N (39.5 %) and quaternary-N (58 %), and a minor peak at 403 eV, which is attributed to N-oxides of pyridine-N. 24,25 The weight ratio N/C is 0.026 for the bulk (elemental analysis) and 0. To characterize the porosity and surface area of the two synthesized materials as well as the original CNTs, N 2 adsorption measurements were performed.…”

Section: Chemical and Structural Characterizationmentioning

confidence: 99%

Surface Modification of CNTs with N-Doped Carbon: An Effective Way of Enhancing Their Performance in Supercapacitors

Sevilla

Zhao

et al. 2014

ACS Sustainable Chem. Eng.

119

View full text Add to dashboard Cite

show abstract

“…In contrast, the comparatively more delayed metamorphic decrease of pyrrolic/pyridone nitrogen (N-5; Fig. 7c, d) may be explained by (i) a conversion of pyridone to pyrrole (Brent et al, 1970;Schmiers et al, 1999), and (ii) by the difficulty of expanding pyrrole-type rings to pyridine-type rings as suitable building blocks for accreting graphitic structures. Few nitrogen concentration data have been published for natural graphite (van Zuilen et al, 2005).…”

Section: Increase Of N-c 3 Substituting For Carbon In Condensed Partmentioning

confidence: 99%

“…Experimental dry, open-system programmed pyrolysis of model substances shows that pyridinic, pyrrolic and N-C 3 -type nitrogen species are remarkably stable at high temperature (e.g., Stanczyk and Boudou, 1994;Schmiers et al, 1999;Xiao et al, 2005;Boudou et al, 2006). Modelling with Optkin or 2D Petromod software, for example, justifies the early pyrolytic elimination of only a minor amount of anthracitic N org , even under high heat flow of up to 80 W/cm 2 from the Carboniferous to present time (Littke et al, 1995), in reality most N org is not eliminated throughout low grade metamorphism (Boudou and Espitalié, 1995).…”

Section: The Role Of H O-containing Hot Fluids During Transformationmentioning

confidence: 99%

Organic nitrogen chemistry during low-grade metamorphism

Boudou

Schimmelmann

Ader

et al. 2008

Geochimica et Cosmochimica Acta

136

View full text Add to dashboard Cite

-Most of the organic nitrogen (N org ) on Earth is disseminated in crustal sediments and rocks in the form of fossil nitrogen-containing organic matter. The chemical speciation of fossil N org within the overall molecular structure of organic matter changes with time and heating during burial. Progressive thermal evolution of organic matter involves phases of enhanced elimination of N org and ultimately produces graphite containing only traces of nitrogen. Long-term chemical and thermal instability makes the chemical speciation of N org a valuable tracer to constrain the history of sub-surface metamorphism and to shed light on the subsurface biogeochemical nitrogen cycle and its participating organic and inorganic nitrogen pools. This study documents the evolutionary path of N org speciation, transformation and elimination before and during metamorphism and advocates the use of XRay Photoelectron Spectroscopy (XPS) to monitor changes in N org speciation as a diagnostic tool for organic metamorphism. Our multidisciplinary evidence from XPS, stable isotopes, traditional quantitative coal analyses, and other analytical approaches shows that at the metamorphic onset N org is dominantly present as pyrrolic and pyridinic nitrogen. The relative abundance of nitrogen substituting for carbon in condensed, partially aromatic systems (where N is covalently bonded to three C atoms) increases exponentially with increasing metamorphic grade, at the expense of pyridinic and pyrrolic nitrogen. At the same time, much N org is eliminated without significant nitrogen isotope fractionation. The apparent absence of Rayleigh-type nitrogen isotopic fractionation suggests that direct thermal loss of nitrogen from an organic matrix does not serve as a major pathway for N org elimination. Instead, we propose that hot H, O-containing fluids or some of their components gradually penetrate into the carbonaceous matrix and eliminate N org along a progressing reaction front, without causing nitrogen isotope fractionation in the residual N org in the unreacted core of the carbonaceous matrix. Before the reaction front can reach the core, an increasing part of core N org chemically stabilizes in the form of nitrogen atoms substituting for carbon in condensed, partially aromatic systems forming graphite-like structural domains with delocalized π-electron systems (nitrogen atoms substituting for "graphitic" carbon in natural metamorphic organic matter). Thus, this nitrogen species with a conservative isotopic composition is the dominant form of residual nitrogen at higher metamorphic grade.

show abstract

Change of chemical bonding of nitrogen of polymeric N-heterocyclic compounds during pyrolysis

Cited by 237 publications

References 18 publications

Revisiting the chemistry of graphite oxides and its effect on ammonia adsorption

Revisiting the chemistry of graphite oxides and its effect on ammonia adsorption

Surface Modification of CNTs with N-Doped Carbon: An Effective Way of Enhancing Their Performance in Supercapacitors

Organic nitrogen chemistry during low-grade metamorphism

Contact Info

Product

Resources

About