Reactivity of some organic compounds with supercritical water

Houser, Thomas J.; Tiffany, David M.; Li, Zhuangjie; McCarville, M. Beth; Houghton, Michael E.

doi:10.1016/0016-2361(86)90077-3

Cited by 83 publications

(72 citation statements)

References 10 publications

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“…These experimental low N 2 yields during artificial heating of coals cannot explain the strong loss of N org during natural anthracitization. Instead, they indirectly support other experimental evidence for ammonia being the main inorganic nitrogen product from hydrous pyrolysis of kerogen and model compounds (Ader et al, 1998a(Ader et al, , b, 2000, as well as of other nitrogen heterocyles (Houser et al, 1986(Houser et al, , 1989Katritzky et al, 1995Katritzky et al, , 1997Ogunsola, 2000;Yuan et al, 2006).…”

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

confidence: 67%

Organic nitrogen chemistry during low-grade metamorphism

Boudou

Schimmelmann

Ader

et al. 2008

Geochimica et Cosmochimica Acta

136

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-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.

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

confidence: 67%

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

show abstract

“…Streit (1988, 1989) included elementary reaction steps that involved water as a reactant in their detailed kinetic models of methane oxidation in SCW. Additionally, several pyrolysis studies in SCW revealed that water was an active participant in the reaction and not merely an inert solvent (Lawson and Klein, 1985;Townsend and Klein, 1985;Townsend et al, 1988;Huppert et al, 1989;Houser et al, 1986).…”

Section: Effect Of Pressurementioning

confidence: 99%

Kinetics of phenol oxidation in supercritical water

1992

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“…Weingartner and Franck [28] disclosed that ionic product falls by orders of magnitude at SCW condition, thus is able to produce H and OH radicals under experimental conditions. Heteroatom containing organics present in the body can react with water via hydrolysis [14], [17], [18]. Moriya and Enomoto [29], Arai and Adschiri [20] and Mandal et al [9] reported that the effect of SCW on the pure hydrocarbon decomposition is insignificant.…”

Section: Resultsmentioning

confidence: 99%

“…Sato et al in 2003 [12] discovered that SCW is favorable for the decomposition of alkylphenols in water. Very few studies have been conducted on the pyrolysis of hydrocarbons in SCW by Houser et al [18] in 1986, Hirth and Franck [19] in 1993, Arai and Adschiri [20] in1999, Ederer et al [21] in 1999, Savage [22] in 1999, Ding et al [23] in 2006 and Mandal et al [9] in 2011. These studies showed that water had no significant effect on the pyrolysis of alkylbenzenes.…”

Section: Introductionmentioning

confidence: 99%

Comparison Study of Heptylbenzene and Hexylbenzene Decomposition under Supercritical Water

MandalMandal¹,

Chowdhury²,

Sasaki³

2016

IJCEA

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Abstract-The world reserves of conventional light oils are decreasing and being replaced by an increasing amount of heavy oils. Heptylbenzene (HPB) and hexylbenzene (HXB) are compounds that are also present in heavy oils. This study is aimed at comparing the supercritical hydrolysis reaction of HPB and HXB producing low molecular weight hydrocarbons. The dramatic change in the ionic product and the dielectric constant of water under supercritical conditions makes it an acid or a base catalyst. In this study, water was used without any catalyst. The reaction was carried out in an 8.8 mL batch type reactor fabricated from Hastelloy C-276 whose respective design temperature and pressure was 500 o C and 50 MPa. The comparison study on the ability of supercritical water (SCW) to decompose HPB and HXB were studied at temperatures of 450-475 o C and water partial pressure (WPP) of 35 MPa. The experimental results show that conversion as well as production of low molecular weight compounds was high at water to oil ratio of 10, a reaction time of 60 min and a temperature of 475 o C. The supercritical water was found to be potential to convert the heavy oils into the lighter oils without the addition of any catalyst.

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Reactivity of some organic compounds with supercritical water

Cited by 83 publications

References 10 publications

Organic nitrogen chemistry during low-grade metamorphism

Organic nitrogen chemistry during low-grade metamorphism

Kinetics of phenol oxidation in supercritical water

Comparison Study of Heptylbenzene and Hexylbenzene Decomposition under Supercritical Water

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