Kinetic Elucidation of the Acid-Catalyzed Mechanism of 1-Propanol Dehydration in Supercritical Water

Narayan, Ram C.

doi:10.1021/bk-1989-0406.ch015

Cited by 19 publications

(14 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…They reported that an E2 mechanism was consistent with their experimental kinetics results for both propanol and ethanol dehydration in SC water (Narayan and Antal, 1989;Xu et al, 1990), whereas an E l mechanism was not consistent. The ethanol mechanism involved a protonated alcohol as an intermediate species, whereas the propanol mechanism may be concerted and avoid the formation of the charged intermediate (Narayan and Antal, 1990).…”

Section: Liquefaction and Degradation Of Biomassmentioning

confidence: 85%

“…The ethanol mechanism involved a protonated alcohol as an intermediate species, whereas the propanol mechanism may be concerted and avoid the formation of the charged intermediate (Narayan and Antal, 1990). They also reported rate constants for the elementary reaction steps for propanol at 375°C and 34.5 MPa (Narayan and Antal, 1989) and for ethanol at 385°C and 34.5 MPa (Xu et al, 1990(Xu et al, , 1991. The propanol studies were extended to examine the influence of pressure on the kinetics at 375°C (Narayan and Antal, 1990).…”

Section: Liquefaction and Degradation Of Biomassmentioning

confidence: 99%

See 1 more Smart Citation

Reactions at supercritical conditions: Applications and fundamentals

et al. 1995

View full text Add to dashboard Cite

Section: Liquefaction and Degradation Of Biomassmentioning

confidence: 85%

Section: Liquefaction and Degradation Of Biomassmentioning

confidence: 99%

Reactions at supercritical conditions: Applications and fundamentals

et al. 1995

View full text Add to dashboard Cite

“…power systems using SC steam cycles and in some geochemical processes. The technological applications in which SC water is considered as a solvent and/or reaction medium include destructive oxidation of hazardous wastes (Model1 et al, 1982;Thomason and Modell, 1984;Staszak et al, 1987); conversion of coal (Model1 et al, 1978;Penninger, 198.51, and production of chemicals (Narayan and Antal, 1989). Huang et al (1989a,b) consider the technologically important corrosion processes of alloys in SC water.…”

Section: Introductionmentioning

confidence: 99%

“…They speculated that regions of increased local water density about reactant molecules might contribute to the unusual kinetic behavior. Penninger (1985) and Narayan and Antal (1989) concluded that ionic species (despite the relatively low degree of dissociation in SC water) play important roles in catalyzing some reactions that occur in SC water. We suggest that fundamental understanding of some of these technologically important applications of SC water might be substantially improved through understanding the solvation structures around solutes dissolved in SC water.…”

Section: Introductionmentioning

confidence: 99%

Solvation in supercritical water

Cochran

Cummings

Karaborni

1992

Fluid Phase Equilibria

View full text Add to dashboard Cite

Cochran, H.D., Cummings, P.T. and Karaborni, S., 1992. Solvation in supercritical water. The aim of this work is to determine the solvation structure in supercritical water compared with that in ambient water and in simple supercritical solvents. Molecular dynamics studies have been undertaken of systems that model ionic sodium and chloride, atomic argon, and molecular methanol in supercritical aqueous solutions using the simple point charge model of Berendsen for water. Because of the strong interactions between water and ions, ionic solutes are strongly attractive in supercritical water, forming large regions of increased local water density around each ion comparable to the solvent structures surrounding attractive solutes in simple supercritical fluids. Likewise, the deficit of water molecules surrounding a dissolved argon atom in supercritical aqueous solutions is comparable to that surrounding repulsive solutes in simple supercritical fluids. Methanol appears to be a weakly attractive or even repulsive solute in supercritical water. Only a small number of excess water molecules (if any) surround a methanol molecule in supercritical water, and this becomes a deficit at higher density. The number of hydrogen bonds per water molecule in supercritical water was found to be about one-third the number in ambient water. The number of hydrogen bonds per water molecule surrounding a central particle in supercritical water was only weakly affected by the identity of the central particle -atom, molecule or ion. These results should be helpful in developing a qualitative understanding of important processes which occur in supercritical water.

show abstract

“…In keeping with the assumption of constant water concentration, we also assume that the density of the reactant mixture does not change as the reaction progresses; therefore, the velocity of the fluid is constant down the length of the reactor. More detailed examples of this approach have been given by Narayan and Antal (1989), Xu et al (1990Xu et al ( , 1991, and Xu (1992).…”

mentioning

confidence: 99%

Kinetics and mechanism of isobutene formation from T‐butanol in hot liquid water

Antal

1994

AIChE Journal

View full text Add to dashboard Cite

Isobutene is the only product of the uncatalyzed and acid-catalyzed dehydration of tert-butanol in compressed liquid water at 250°C. The uncatalyzed dehydration reaction is fast: equilibrium is established after about 30 s. Only one of many chemically-motivated kinetic models is able to f i t all the experimental data. This model presumes a heterolytic dehydration mechanism that involves protonated alcohol, carbocation, di-tert-butyl ether, and protonated ether as intermediates. The model permits tert-butanol to dissociate as both an Arrhenius acid and a Bronsted acid while catalyzing its dehydration to isobutene. The pK, of tert-butanol at 250°C is predicted to be about 9, whereas its value at normal temperature and pressure is 18. This I @ increase in the K, value of tert-butanol hints of the promising new world of reaction chemistry in near-and supercritical water.

show abstract

Kinetic Elucidation of the Acid-Catalyzed Mechanism of 1-Propanol Dehydration in Supercritical Water

Cited by 19 publications

References 0 publications

Reactions at supercritical conditions: Applications and fundamentals

Reactions at supercritical conditions: Applications and fundamentals

Solvation in supercritical water

Kinetics and mechanism of isobutene formation from T‐butanol in hot liquid water

Contact Info

Product

Resources

About