Thermodynamics of sulphuric acid: apparent and partial molar heat capacities and volumes of aqueous HSO–4 from 10–55 °C and calculation of the second dissociation constant to 350 °C

Hovey, Jamey K.; Hepler, Loren G.

doi:10.1039/ft9908602831

Cited by 50 publications

(35 citation statements)

References 52 publications

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“…The corrosion current model is based on measurements of the corrosion current density for different temperatures, polarization times and polarization potentials, which are published in [13], and on measurements of the increase in internal resistance due to introduction of functional groups of COOH and C¼O in the surface of the electrode which occur during the corrosion process. These measurements are published in [14]. These demonstrate that the corrosion current density increases linearly with polarization time until it reaches its maximum value.…”

Section: Electrochemical Modelmentioning

confidence: 89%

“…However, Stirring or agitation, for instance due to the electrolyte flow rate, reduces the thickness of the diffusion layer at the surface of the [20]. Table 4 Diffusion coefficients for the Nafion membrane (temperature dependency is not taken into account for the simulation) [14].…”

Section: Battery Characteristicsmentioning

confidence: 99%

“…It is assumed that the flow rate of the positive and negative electrolyte is equal (Q = Q + = Q À ) as are the temperatures in the tanks on the positive and negative side (T t ¼ T þ ¼ T À ), the volumes of the tanks (V t ¼ V þ ¼ V À ) and the heat transfer of the tanks (U À A À ¼ U þ A þ ). The heat capacity C p ½JK À1 kg À1 is calculated each time step based on the group distribution method and data taken from [14][15][16][17][18].…”

Section: Electrochemical Modelmentioning

confidence: 99%

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Multi-physics Model for the Aging Prediction of a Vanadium Redox Flow Battery System

Merei

Adler

Magnor

et al. 2015

Electrochimica Acta

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Section: Electrochemical Modelmentioning

confidence: 89%

Section: Battery Characteristicsmentioning

confidence: 99%

Section: Electrochemical Modelmentioning

confidence: 99%

See 1 more Smart Citation

Multi-physics Model for the Aging Prediction of a Vanadium Redox Flow Battery System

Merei

Adler

Magnor

et al. 2015

Electrochimica Acta

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“…The detailed characteristics of the thermodynamic and physical properties of aqueous sulfuric acid solutions are provided in previous studies . These studies analyze the isopiestic measurement data for the average ion activity coefficients, γ ± , water activities,

a_{H_{2} normalO}

, osmotic coefficient, and excess Gibbs free energy.…”

Section: Proton Aciditymentioning

confidence: 99%

Solvated proton as the main reagent and a catalyst in the single-stage aromatic sulfonation and protodesulfonation of sulfonic acids

2017

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This review is devoted to the critical analysis of the existing contradictory ideas about kinetic description and the mechanisms of electrophilic aromatic substitution (EAS), ie, reversible arene sulfonation and hydrolysis (protodesulfonation) of arenesulfonic acids. Contemporary scientific and educational literature contains prevailing, widespread points of view on the multistage nature processes of the EAS that proceed via πand σ-complexes and are accompanied by arenium ion formation. This interpretation does not account for determining influence of the medium, and the process accompanies the loss of aromaticity. The review presents an alternative point of view: These processes proceed via singlestage and the same transition state. To substantiate this position, we reviewed in detail the contemporary ideas on the solvated proton structure, the limits of applicability of acidity function Н о and excess acidity Х scales, and the experimental solubility data of arenesulfonic acid hydrates in sulfuric acid. This solubility depends on the medium acidity (h o ), which provides the formation of 3 conjugated types of hydrates: anionic (АrSO 3 − ·H 2 O), hydroxonium-arene sulfonated (АrSO 3 − ·H 3 O + ), and the hydroxonium complex with the H-form of АrSO 3 Н·H 3 O + acid. In sulfuric acid solutions with an excess of water, irreversible hydrolysis proceeds with the participation of ArSO 3 − ·H 3 O + . However, protodesulfonation becomes reversible and proceeds with the participation of ArSO 3 Н·H 3 O + in solutions with an excess of sulfuric acid. A conclusion has been made about determining the role of the hydrated proton environment by means the formation of a cyclic transition state. An alternative 2-stage mechanism of EAS is logically and energetically unsubstantiated and, therefore, should be rejected.

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“…Les propriétés thermodynamiques de ce système ont fait l'objet de nombreuses études au cours des 80 dernières années (1)(2)(3)(4)(5)(6)(7)(8). Une de ces propriétés est le coefficient d'activité qui indique l'activité de l'acide différente de sa concentration.…”

Section: Introductionunclassified

Coefficient d'activité de l'acide sulfurique déterminé par titrage infrarouge

Ménichelli¹,

Ma×²,

Chapados³

2000

Can. J. Chem.

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Le titrage fait par spectroscopie infrarouge (IR) en utilisant la technique de la réflexion totale atténuée (Attenuated total reflexion, ATR) des solutions aqueuses de l'acide sulfurique H 2 SO 4 est effectué pour des pH variant entre 0 et 14 dans la gamme de concentrations 1,89 à 0,01 M. La soustraction du spectre de l'eau dans les spectres des solutions est faite en tenant compte de l'eau acide, neutre et basique qui ont des spectres différents. Les spectres résultants sont les spectres de mélanges des espèces ioniques HSO 4 − et SO 4 2 − . Pour chaque concentration, l'analyse par facteurs (AF), donne le spectre des espèces ioniques pures et les facteurs multiplicatifs (FM) dont on tire la distribution des espèces en fonction du pH. Cette distribution est semblable à celle qui est obtenue à partir des équations d'équilibre. La mesure IR permet d'obtenir directement le rapport des coefficients d'activité des ions HSO 4 − et SO 4 2 − . Ce rapport varie essentiellement avec la concentration des ions sans dépendre de leur concentration relative. L'ajustement des courbes de titrage volumétrique expérimental et théorique dans les régions à haut et à bas pH a permis de déterminer les coefficients moyens d'activité des autres espèces présentes en solution. Les valeurs obtenues sont similaires à celles obtenues par mesures électrochimiques. Ceci montre que la spectroscopie IR peut-être utilisée pour étudier des solutions aqueuses d'acides inorganiques allant de concentrations faibles aux concentrations élevées. Abstract:The titration of sulphuric acid by infrared spectroscopy using the attenuated total reflection (ATR) technique was made in the 0 to 14 pH range for solutions ranging from 1.89 to 0.01 M. The subtraction of the water spectrum was made using acidic, neutral, and basic waters which exhibit different spectra. The results gave the spectra of mixtures of the HSO 4 − and SO 4 2 − ionic species in solutions. For each concentration, factor analysis (FA) sorted the spectra of the pure ionic species and gave through the multiplying factors (MF) the distribution of the species as a function of pH. This distribution is the same as that obtained from the equilibrium equations. The IR measurements gave directly the ratios of the activity coefficients of HSO 4 − and SO 4 2 − ions. This ratio varies with the total concentration of both ions but is independent of the relative concentration. The fitting of the experimental and theoretical volumetric titration curves in the high and low pH regions gave the mean activity coefficients of the other species present in the solutions. The values obtained are comparable to those obtained by electrochemical measurements. These results show that it is possible to use IR spectroscopy to study aqueous solutions of inorganic acids from low to high concentrations.

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Thermodynamics of sulphuric acid: apparent and partial molar heat capacities and volumes of aqueous HSO–4 from 10–55 °C and calculation of the second dissociation constant to 350 °C

Cited by 50 publications

References 52 publications

Multi-physics Model for the Aging Prediction of a Vanadium Redox Flow Battery System

Multi-physics Model for the Aging Prediction of a Vanadium Redox Flow Battery System

Solvated proton as the main reagent and a catalyst in the single-stage aromatic sulfonation and protodesulfonation of sulfonic acids

Coefficient d'activité de l'acide sulfurique déterminé par titrage infrarouge

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