Organic Chemical Reactions in Supercritical Water

Savage, Phillip E.

doi:10.1021/cr9700989

Cited by 1,308 publications

(716 citation statements)

References 162 publications

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“…Eventually, after residence times of about 1 minute, full mineralization occurs to C0 2 , H 2 0, molecular N 2 , and inorganic acids associated with the heteroatoms (Cl, S, P, F). A key area many research groups have focused on is characterizing the rates and mechanisms of hydrolysis and oxidation reactions of model compounds under well-defined reaction conditions of T, P, p, x ir and residence time (Tester et al, 1993(Tester et al, ,1998Savage et al, 1995Savage et al, ,1999.…”

Section: Chemical and Phase Reactions In Supercritical Watermentioning

confidence: 99%

Guidelines for Phase Separations in High-Temperature and Supercritical Water Solutions: A Report on a Workshop Organized by the U.S. Army Research Office and the Forschungzentrum Karlsruhe, 7-9 July 1999

Shaw¹,

Boukis²

2000

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Approved for public release; distribution unlimited. AbstractThe U.S. Army is developing supercritical water oxidation for destruction of military toxic materials. The properties of high-temperature aqueous solutions are not, in most cases, well known. Understanding the phase behavior of these solutions will facilitate design and efficient operation of high-temperature water reactors. A U.S. Army workshop held at the Forschungzentrum Karlsruhe in July 1999 assembled experts on phase behavior to develop guidelines that, in the absence of more complete knowledge of solution properties, will aid reactor designers and operators. The experts presented papers on model systems, properties of high-temperature aqueous solutions, and chemistry in high-temperature water. Following these presentations, the experts developed some of the desired rules of thumb and made recommendations for research to develop these guidelines further. This workshop report includes the presentation papers, guidelines, and recommendations for research. Distribution 67Report Documentation Page 71 Participants in the workshop 2Hong, Model Systems P-T-x diagram for Type la systems and Type lb systems 122. T-x diagram for NaCI-H 2 0 at 250 bar 13 3. P-T projection of solidus for NaCI-H 2 0 14 4. P-T-x diagrams for Type 2a systems, and Type 2b systems 14 5. T-x projection of phase diagram for ternary systems of Type 1: subtype A, subtype B, and subtype C 16 6. P-T projection of eutonic curve for NaCl-Na 2 S04-H 2 0 system ... 177. Temperature progression of phase diagrams at 225 bar for NaCINa 2 S04-H 2 0 system 17 Supercritical water (SCW) oxidation (SCWO) provides a powerful means to transform toxic organic materials into simple, relatively inert oxides. Water at high temperatures and pressures is an active medium, however, and its properties and those of its solutions are only partially understood. Indeed, two principal challenges to broad use of this technology are (1) the materials requirements for the reactor and the heatup and cooldown sections, and (2) the incomplete understanding of and ability to predict the phase behavior of SCW solutions.Phase separations have the potential to impair the operation of an SCWO reactor (1) by dramatically changing transport properties (especially in the presence of dynamically separating liquid and solid phases), (2) by generating solid particles that may plug reactor orifices and deposit on reactor surfaces, and (3) by producing a highly corrosive electrochemical environment. Objectives for This WorkshopWe sought to develop (or recommend methodologies to develop) guidelines/rules of thumb for phase separations in organic/salt/gas/aqueous solutions in SCWO processing for defined sets of feed compositions. Useful speculations about these phase separations are in the areas not only of equilibrium thermodynamics (e.g., solubility), but also of the kinetics of phase separation and growth (e.g., the problem of heterogeneous nucleation). The phase separation guidelines are intended to indicate regions of safe (pr...

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Section: Chemical and Phase Reactions In Supercritical Watermentioning

confidence: 99%

Guidelines for Phase Separations in High-Temperature and Supercritical Water Solutions: A Report on a Workshop Organized by the U.S. Army Research Office and the Forschungzentrum Karlsruhe, 7-9 July 1999

Shaw¹,

Boukis²

2000

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“…Some researchers believe that SCW could not only serve as the solvent but also provide the activehydrogen for capping of reactive fragments to form more light components and less coke in upgrading heavy oil (Cheng et al, 2009;Kozhevnikov et al, 2010;Morimoto et al, 2010;Sato et al, 2003;Watanabe et al, 2010;Zhao et al, 2006). It is also reported that C-O bonds in ethers and esters, C-S bonds in aliphatic chain and metal elements incorporated in asphaltene are easily broken in SCW (Mandal et al, 2011(Mandal et al, , 2012bSavage, 1999). Unfortunately, upgrading asphaltene in SCW has not garnered attention until recently.…”

Section: Introductionmentioning

confidence: 99%

Kinetic and reaction pathway of upgrading asphaltene in supercritical water

Yan

Xiao

2015

Chemical Engineering Science

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“…1,2 Supercritical (sc) fluids of molecules containing hydrogen bonds, such as supercritical water (SCW, T c = 657 K, P c = 22.1 MPa, r c = 0.32 g cm À3 ) and methanol (SCM, T c = 513 K, P c = 8.1 MPa, r c = 0.27 g cm À3 ), have been a target of recent research in fundamental and applied sciences, especially in the field of environmentally friendly chemistry and as reaction media for the decomposition of hazardous organic compounds and recovery of useful chemicals from industrial wastes. 3 The study of supercritical water (SCW) is thus relevant to the widespread use of supercritical solvents in industrial reactions and separation science. SCW consists of highly excited molecules 9 and is believed to be important in the geological formation of hydrocarbons.…”

Section: Introductionmentioning

confidence: 99%

Hydrogen bond dynamics of superheated water and methanol by ultrafast IR-pump and EUV-photoelectron probe spectroscopy

Vöhringer‐Martinez

Link

Lugovoy

et al. 2014

Phys. Chem. Chem. Phys.

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Supercritical water and methanol have recently drawn much attention in the field of green chemistry. It is crucial to an understanding of supercritical solvents to know their dynamics and to what extent hydrogen (H) bonds persist in these fluids. Here, we show that with femtosecond infrared (IR) laser pulses water and methanol can be heated to temperatures near and above their critical temperature T c and their molecular dynamics can be studied via ultrafast photoelectron spectroscopy at liquid jet interfaces with high harmonics radiation. As opposed to previous studies, the main focus here is the comparison between the hydrogen bonded systems of methanol and water and their interpretation by theory. Superheated water initially forms a dense hot phase with spectral features resembling those of monomers in gas phase water. On longer timescales, this phase was found to build hot aggregates, whose size increases as a function of time. In contrast, methanol heated to temperatures near T c initially forms a broad distribution of aggregate sizes and some gas. These experimental features are also found and analyzed in extended molecular dynamics simulations. Additionally, the simulations enabled us to relate the origin of the different behavior of these two hydrogen-bonded liquids to the nature of the intermolecular potentials. The combined experimental and theoretical approach delivers new insights into both superheated phases and may contribute to understand their different chemical reactivities.

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Organic Chemical Reactions in Supercritical Water

Cited by 1,308 publications

References 162 publications

Guidelines for Phase Separations in High-Temperature and Supercritical Water Solutions: A Report on a Workshop Organized by the U.S. Army Research Office and the Forschungzentrum Karlsruhe, 7-9 July 1999

Guidelines for Phase Separations in High-Temperature and Supercritical Water Solutions: A Report on a Workshop Organized by the U.S. Army Research Office and the Forschungzentrum Karlsruhe, 7-9 July 1999

Kinetic and reaction pathway of upgrading asphaltene in supercritical water

Hydrogen bond dynamics of superheated water and methanol by ultrafast IR-pump and EUV-photoelectron probe spectroscopy

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