Electrical Conductances of Aqueous Solutions at High Temperature and Pressure. II. The Conductances and Ionization Constants of Sulfuric Acid—Water Solutions from 0 to 800° and at Pressures up to 4000 Bars<sup>1,2</sup>

Quist, Arvin S.; Marshall, William L.; Jolley, Hadley

doi:10.1021/j100892a040

Cited by 74 publications

(45 citation statements)

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“…The k * values showed an evident dependence on temperature as well as on H 2 SO 4 initial concentration, and thus an acid catalysis correlation, taking into account the H 3 O + influence on the reaction, needed to be formulated. It is known from literature that the second dissociation constant of sulphuric acid varies significantly with temperature and with the ionic strength of the solution, Dickinson et al [1990], Marshall and Jones [1966], Quist et al [1965], and it is important to take into account those temperature effects in the kinetic formulation as observed by many authors, Antal Jr et al [1991], Zeitsch [2000]. Within the range of conditions of interest for this work, aqueous sulphuric acid can be considered with good approximation to be present as H 3 O + and HSO − 4 .…”

Section: Resultsmentioning

confidence: 99%

“…In this temperature range the reaction is very slow and thus k * values rather small (∼ 10 −5 ). Sulphuric acid thermodynamics at various pressure and temperature conditions have been thouroughly studied by many authors, Dickinson et al [1990], Quist et al [1965], Marshall and Jones [1966]. Nevertheless, an explicit correlation for individual ion activity coefficients depending on temperature, pressure and ionic strength has not yet been formulated.…”

Section: Resultsmentioning

confidence: 99%

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Bioenergy II: Furfural Destruction Kinetics during Sulphuric Acid-Catalyzed Production from Biomass

Marcotullio¹,

Jong²,

Cardoso³

et al. 2009

International Journal of Chemical Reactor Engineering

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The interest for furfural has increased in the last years due to its potential for competing with oil derivatives as platform chemical. In addition, furfural, derived from C 5 sugars, can play a key role in the valorization of the hemicellulose contained in biomass when considering the development of a modern biorefinery concept. The development of such new and competitive biorefinery processes must be based on accurate kinetic data for the reactions involving furfural in the conditions used for its production.This work addresses the determination of furfural destruction kinetics in aqueous acidic environment, using sulphuric acid as catalyst, in the temperature range 150 -200• C, acid concentration range 36.4 -145.5 mM and furfural initial concentration between 60.4 and 72.5 mM. These studies were carried out using a recently built lab-scale titanium reactor that enables liquid phase reactions in a relatively broad range of conditions.The obtained results show that destruction of furfural follows first-order reaction kinetics within the range of temperature and acid concentration evaluated. Moreover, the proposed kinetic model takes into account the effects of temperature and acid dilution on the ions activity, and thus H 3 O + , by using the electrolyte Non-Random Two-Liquid (eNRTL) model. By using this approach, the rate constant dependence on temperature could be described by the Arrhenius law and thus the activation energy could be estimated as being 125. Contrarily to what is reported in previous works, formic acid formation from furfural under the tested conditions can be regarded as playing a far less pronounced role than suggested before.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Bioenergy II: Furfural Destruction Kinetics during Sulphuric Acid-Catalyzed Production from Biomass

Marcotullio¹,

Jong²,

Cardoso³

et al. 2009

International Journal of Chemical Reactor Engineering

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“…The results of series of experiments at 300.0" and roughly constant ionic strength hydrogen sulfate ion, HS0,-, behaves as a univalent, non-basic, non-acidic ion between 300 and 400" (28), and a solution, 2 M in LiClO, and 3 M in NaHSO, at 20°, showed no decomposition after 55 h at 294.5". The effect of added NaHSO, on the rate of decomposition of 2 M (20") HC10, is illustrated by the data of Table 4, which show that a modest but definite "medium" or "ionic strength" effect causes the rate of HClO, decomposition to decrease as the electrolyte concentration increases.…”

Section: Kinetics Of Decomposition Of Aqueous Perchloricmentioning

confidence: 94%

Kinetics of Thermal Decomposition of Aqueous Perchloric Acid

Henderson¹,

Miasek²,

Swaddle³

1971

Can. J. Chem.

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Thermal decpmposition of 1.1-6.6 m aqueous perchloric acid at 295-322" yields oxygen, chlorine, and a small quantity of hydrochloric acid. The initial rates of decomposition have been measured, using a perchlorate ion activity electrode, and show 3.5 order dependence on the stoichiometric perchloric acid concentration; the corresponding rate coefficient and activation energy at 300.0" are 3.1 x lo-' tn-2.5 s-' and 84 kcal mole-', respectively. The order of reaction with respect to time is less than 3.5 and depends upon the initial perchloric acid concentration; this effect is due to acceleration of the decomposition by the reaction products, notably chloride ion. It is suggested that the ratedetermining step in the decomposition of aqueous perchloric acid is the reaction of two undissociated HC10, molecules to give H 2 0 , CIO,, and C10,. Perchloric acid is used extensively in physical studies of phenomena in aqueous solution, since it is the strongest of the common acids and also because its anion has remarkably little tendency to form complexes with metal ions. The aqueous acid is, however, thermodynamically unstable (AGO = -26.3 kcal/mole-' at 25" for the hypothetical 1 rn solution (1)) with respect to decomposition to oxygen, chlorine, and water, and it is clear that the kinetics of this decomposition must be known if the acid is to be used in extending studies of aqueous electrolyte solutions to high temperatures.Accordingly, the present study was designed primarily to provide empirical rate data on the decomposition of aqueous perchloric acid as a function of temperature, and over a concentration range which would include the commonlychosen "swamping electrolyte" values, 1-6 m. A literature search for such information was unsuccessful, although it has been reported (2) that no chlorine, DOCI, DCIO,, or DCIO, can be detected spectroscopically in 1 m DCIO, after several days in a titanium vessel with sapphire windows at 250". On the other hand, the decomposition of 83-100% HCIO, has received considerable attention (3-8), as has the decomposition of HC10, vapor (9-12). ExperimentalAll the stock chemicals used in this study were "Baker Analyzed" reagent grade, with the exception of ammonium nitrate (Matheson, Coleman and Bell) and sodium nitrate (Fisher Certified reagent). The perchloric acid (72%) was used without further purification; the experi-'To whom correspondence should be addressed. mental results were independent of the manufacturer's batch. Lithium perchlorate trihydrate was made from lithium carbonate and perchloric acid. Distilled water was passed through Barnstead deionizer and organic removal cartridges before use. Red mercuric oxide was used as the primary standard in acidimetry. Spectrophotometric measurements were made using a Cary Model 15 spectrometer.The pressure vessels used consisted of a cylindrical body (2.54 cm i.d. x 4.60 cm 0.d.) of ATL-40 commercially pure titanium, 0.2% palladium alloy (Atlas Titanium, Welland, Ontario), with a plug of the same material, such that the cavity volum...

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“…Aqueous HS0,-ion becomes progressively less acidic up to 300 "C, and it is neither appreciably acidic nor basic between 300 and 400 "C (19). Thus hydrolysis of chromium(111) sulfate at high temperatures is aided by protonation of SO,'-only as far as HS0,-, and the observed complexing of chromium(111) by SO,'-will suppress further hydrolysis.…”

Section: Hydrolytic Precipitation Reactionsmentioning

confidence: 96%

The Aqueous Chemistry of Chromium(III) above 100 °C: Hydrothermal Synthesis of Chromium Spinels

Swaddle¹,

Lipton²,

Guastalla³

et al. 1971

Can. J. Chem.

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The hydrothermal deposition of CrO(OH) from aqueous chromium(III) chloride, nitrate, and perchlorate, and of Cr3(SO4)2(OH)5•H2O and Cr(OH)SO4•2H2O(?) from aqueous chromium(III) sulfate, has been investigated. Aqueous chromium(III) is oxidized to chromium(VI) by 0.4 M perchloric acid above 225 °C, and by molecular oxygen above 250 °C. Aqueous chromium(III) can react at 300 °C with iron or steel, cobalt, and copper to produce FeCr2O4, CoCr2O4, and Cu2Cr2O4, respectively. CrO(OH) reacts with type 316 stainless steel at 440 °C in supercritical water of density 0.7 g cm−3 to yield (Fe,Ni)-Cr2O4, which is the "cubic Cr2O3" of Laubengayer and McCune. The spinels MCr2O4 (M = Mg, Mn, Fe, Co) can be made hydrothermally at ca. 300 °C from Cr(OH)3 and M(OH)2. This information is relevant to corrosion phenomena, and the possible hydrothermal origin of chromite deposits in serpentinized rocks.

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Electrical Conductances of Aqueous Solutions at High Temperature and Pressure. II. The Conductances and Ionization Constants of Sulfuric Acid—Water Solutions from 0 to 800° and at Pressures up to 4000 Bars^1,2

Cited by 74 publications

References 1 publication

Bioenergy II: Furfural Destruction Kinetics during Sulphuric Acid-Catalyzed Production from Biomass

Bioenergy II: Furfural Destruction Kinetics during Sulphuric Acid-Catalyzed Production from Biomass

Kinetics of Thermal Decomposition of Aqueous Perchloric Acid

The Aqueous Chemistry of Chromium(III) above 100 °C: Hydrothermal Synthesis of Chromium Spinels

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Electrical Conductances of Aqueous Solutions at High Temperature and Pressure. II. The Conductances and Ionization Constants of Sulfuric Acid—Water Solutions from 0 to 800° and at Pressures up to 4000 Bars1,2

Cited by 74 publications

References 1 publication

Bioenergy II: Furfural Destruction Kinetics during Sulphuric Acid-Catalyzed Production from Biomass

Bioenergy II: Furfural Destruction Kinetics during Sulphuric Acid-Catalyzed Production from Biomass

Kinetics of Thermal Decomposition of Aqueous Perchloric Acid

The Aqueous Chemistry of Chromium(III) above 100 °C: Hydrothermal Synthesis of Chromium Spinels

Contact Info

Product

Resources

About

Electrical Conductances of Aqueous Solutions at High Temperature and Pressure. II. The Conductances and Ionization Constants of Sulfuric Acid—Water Solutions from 0 to 800° and at Pressures up to 4000 Bars^1,2