Critical Temperatures and Densities of the SO<sub>3</sub>-H<sub>2</sub>O System.

Stuckey, J. E.; Secoy, C. H.

doi:10.1021/je60018a029

Cited by 12 publications

(7 citation statements)

References 4 publications

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“…For the calculation of the collision frequency of HSO 5 in air, o = Z LJ P, with the Lennard-Jones collision number Z LJ and the pressure P, we approximated the Lennard-Jones parameters of HSO 5 , using the relations given by Stiel and Todos 51 and critical parameters of H 2 SO 4 from ref. 52; the data for N 2 and O 2 were taken from ref. 53.…”

Section: Statistical Rate Theory Calculationsmentioning

confidence: 99%

Kinetics of the chemically activated HSO5 radical under atmospheric conditions – a master-equation study

González-García

Olzmann

2010

Phys. Chem. Chem. Phys.

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A detailed theoretical analysis of the HOSO(2) + O(2) reaction is performed, paying special attention to the kinetics of the intermediate HSO(5) radical. The possible formation of the monohydrated adduct, HSO(5)·H(2)O, in the presence of water vapor is examined. For the binding energy of the most stable isomer at T = 0 K, a value of D(0)(HOSO(4)-H(2)O) = 51.7 kJ mol(-1) was obtained at the CCSD(T)/CBS level of theory; other energies were adopted from a recently published high-level quantum chemical study of our laboratory. Molecular geometries and vibrational frequencies of the reactants, intermediates, and products were obtained from B3LYP/cc-pVTZ calculations. Rate coefficients and lifetimes of the HSO(5) intermediate were calculated by solving a master equation with specific rate coefficients from statistical rate theory. The master equation is extended by a bimolecular sink term, which accounts for the HSO(5) + H(2)O reaction. The relation between thermal and chemical activation in this reaction system is examined. The results show that the lifetime of the HSO(5) intermediate under atmospheric conditions is too short for a bimolecular reaction with water to become important. Relative yields of HSO(5)·H(2)O well below 1% were obtained, ruling out this reaction pathway as a relevant source for aerosols.

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Section: Statistical Rate Theory Calculationsmentioning

confidence: 99%

Kinetics of the chemically activated HSO5 radical under atmospheric conditions – a master-equation study

González-García

Olzmann

2010

Phys. Chem. Chem. Phys.

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“…The OH-stretching difference peak position was found to increase linearly with the temperature rise between about 200 and 360 °C, where it was fit by the least-squares equation ∆ν ) 3519.6 + 0.18630t. Substitution of the critical temperature of the 42 mol % acid, t ) 665 °C, 13 into the least-squares equation yields a peak position of 3643 cm -1 . This estimated value is in fairly close agreement with the non-hydrogen-bonded OH stretching frequency of liquid water, namely, about 3625 to 3630 cm -1 , despite the unusually long extrapolation involved.…”

Section: Vibrational Assignments For Hso 4and H 2 So 4 and Raman Spectramentioning

confidence: 99%

“…Stuckey and Secoy 13 reported critical temperatures and densities for aqueous H 2 SO 4 solutions between 0 and 100 mol %, although they did not measure critical pressures. T c is maximal at 61.3 mol % where its value is ∼666 °C (939 K).…”

Section: Vibrational Assignments For Hso 4and H 2 So 4 and Raman Spectramentioning

confidence: 99%

High-Temperature Raman Investigation of Concentrated Sulfuric Acid Mixtures: Measurement of H-Bond ΔH Values between H₃O⁺ or H₅O₂⁺ and HSO₄^-

2002

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Forty-two mol percent sulfuric acid is a room-temperature molten salt composed of H-bonded ion pairs H 3 O + -HSO 4 -(8.2 M) and H 5 O 2 + -HSO 4 -(5.4 M), the former breaking primarily below ∼360 °C and the latter, mainly between ∼360 °C and the critical point. These ruptures produce H 2 SO 4 and H 2 O. Iterative van't Hoff thermodynamic analysis of Raman spectra to 360 °C employing peak height or component area ratios at ∼905 and ∼1035 cm -1 or at ∼1165 and ∼1035 cm -1 yielded an average ∆H of 3.2 ( 0.2 kcal/mol corresponding to H-bond breakage between H 3 O + and HSO 4 -. A Raman ∆H of 5.9 ( 0.3 kcal/mol was measured for the rupture of H 5 O 2 + -HSO 4 -H-bonds between 360 and 513 °C Versus ∼5.7 kcal/mol calculated. H-bonds exist between species other than the two hydronium-bisulfate ion pairs but are not measured by the Raman H 2 SO 4 /HSO 4intensity ratios. Hydrogen bonding wanes near the critical point, ∼665 °C, at which only neutral species, H 2 SO 4 and H 2 O (plus some SO 3 ), remain. A ∆H of 3.5 ( 0.4 kcal/mol was also measured from the 87 mol % acid, close enough to the 3.2 ( 0.2 kcal/mol value to assign both to H 3 O + -HSO 4and also because H 5 O 2 + cannot form in the 87 mol % solution. The integral heat of solution (42 mol %) calculated using Raman data for the two hydronium-bisulfate ion pairs is consistent with the calorimetric value. Values of the dielectric constant were also estimated from Raman data.

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“…31 The strong chemical interaction between SO 3 and H 2 O makes the prediction difficult, although some attempts have been made in the past. 31,32 The hard sphere approach does not consider such interactions; however, they can be represented empirically by the values of the binary adjustable parameters k 12 in eq 6, and the values of l 12 in the combining rule for covolume:…”

Section: Resultsmentioning

confidence: 99%

“…To emphasize this fact more, we have implemented Melchem's modification of the Peng−Robinson EOS 16 for correlating the critical data of the industrially important SO 3 −H 2 O system . The strong chemical interaction between SO 3 and H 2 O makes the prediction difficult, although some attempts have been made in the past. , The hard sphere approach does not consider such interactions; however, they can be represented empirically by the values of the binary adjustable parameters k 12 in eq 6, and the values of l 12 in the combining rule for covolume: …”

Section: Resultsmentioning

confidence: 99%

About the Relation between the Empirical and the Theoretically Based Parts of van der Waals-like Equations of State

Polishuk

Wisniak

Segura

et al. 2002

Ind. Eng. Chem. Res.

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It is demonstrated that empirical temperature functionalities for the cohesive parameter in van der Waals-like equations can be responsible for prediction of nonphysical results such as fictitious critical points of pure compounds, that can result in prediction of unrealistic phase behavior in the entire thermodynamic phase space. Simple numerical tests for detecting this pitfall are proposed, and the roles played by the empirical and the theoretically based parts in semiempirical engineering equations are investigated. In particular, it is demonstrated that improvement of the accuracy with which equations of state approximate the hard sphere virial coefficients makes the theoretical part more self-sufficient for an accurate description of data. This significantly reduces the contribution of the corresponding empirical part and has a positive effect on the overall robustness and reliability of the model. In addition, an improved theoretical base contributes to the ability of the model so simultaneously and accurately predict both liquid and vapor densities.

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Critical Temperatures and Densities of the SO₃-H₂O System.

Cited by 12 publications

References 4 publications

Kinetics of the chemically activated HSO5 radical under atmospheric conditions – a master-equation study

Kinetics of the chemically activated HSO5 radical under atmospheric conditions – a master-equation study

High-Temperature Raman Investigation of Concentrated Sulfuric Acid Mixtures: Measurement of H-Bond ΔH Values between H₃O⁺ or H₅O₂⁺ and HSO₄^-

About the Relation between the Empirical and the Theoretically Based Parts of van der Waals-like Equations of State

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Critical Temperatures and Densities of the SO3-H2O System.

Cited by 12 publications

References 4 publications

Kinetics of the chemically activated HSO5 radical under atmospheric conditions – a master-equation study

Kinetics of the chemically activated HSO5 radical under atmospheric conditions – a master-equation study

High-Temperature Raman Investigation of Concentrated Sulfuric Acid Mixtures: Measurement of H-Bond ΔH Values between H3O+ or H5O2+ and HSO4-

About the Relation between the Empirical and the Theoretically Based Parts of van der Waals-like Equations of State

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Product

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About

Critical Temperatures and Densities of the SO₃-H₂O System.

High-Temperature Raman Investigation of Concentrated Sulfuric Acid Mixtures: Measurement of H-Bond ΔH Values between H₃O⁺ or H₅O₂⁺ and HSO₄^-