Experimentelle Untersuchungen über das thermodynamische Verhalten konzentrierter Halogenwasserstoffsäuren

Haase, Rolf; Naas, H.; Thumm, H.

doi:10.1524/zpch.1963.37.3_4.210

Cited by 60 publications

(18 citation statements)

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“…For example, the x H2O =x HI mole ratio in HI x is only 5.1 which is close not only to the values in HI 67 and HI 57 of 3.5 and 5.4, respectively, but also to the value of 6 in the case of the aquo-complex ions mentioned above, and to its value in the HI-H 2 O azeotrope at 251C which is 5.8 [49]. Of interest here also is a recent theoretical study of the stability of HIwater clusters that found that clusters containing four or more water molecules are more stable when the solvated HI is dissociated into ions, I…”

Section: Concentrated Solutions Of Halogen Acids or Halide Ions Espesupporting

confidence: 74%

Raman scattering studies of the condensed phase of the HIx feed of the sulfur-iodine thermochemical cycle

Ramos-Sánchez

Jeans

Devonshire

2011

Int. J. Energy Res.

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SUMMARYThe species present in the condensed phase of the HI x , hydrogen producing, feed in the water-splitting, sulfur-iodine thermochemical cycle have been investigated using spontaneous Raman scattering. Measurements of I 2 -containing species in the low Raman-shift region from 50 to 400 cm À1 in samples of the two aqueous binary systems, I 2 /H 2 O and HI/H 2 O, and the ternary system HI/I 2 /H 2 O with and without the addition of H 2 SO 4 have provided a consistent picture of the aqueous iodine and polyiodide chemistry. Samples were contained in sealed silica ampoules and were heated to temperatures in the range 20-3001C. The results, which cover a wide range of I 2 and HI mole fractions, and x I2 =x HI mole ratios, in the HI/I 2 /H 2 O system, reveal the co-occurrence of, and H 1 -I À (I 2 ) 2 solvated species in the condensed phase of HI x . Thus, while the first is mostly evident by its strong fundamental band with Raman shift in the range from 110 to 115 cm À1, the other two species appear convoluted in a broad prominent band whose Raman shift ranges between 153 and 172 cm À1 depending on the x I2 =x HI mole ratio. These well characterized Raman features are proposed as an in situ diagnostic for process control of the cycle.

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Section: Concentrated Solutions Of Halogen Acids or Halide Ions Espesupporting

confidence: 74%

Raman scattering studies of the condensed phase of the HIx feed of the sulfur-iodine thermochemical cycle

Ramos-Sánchez

Jeans

Devonshire

2011

Int. J. Energy Res.

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“…Consequently, ATcT currently produces an enthalpy of formation of HBr (-35.85±0.15 kJ mol −1 at 298.15 K) that is higher (less negative) than the value assigned by CODATA by an amount that -while not large in absolute terms -exceeds substantially the combined uncertainties, leading to the conclusion that the aqueous thermochemical route selected by CODATA contains a hidden cumulative systematic bias that is larger than their declared uncertainty. It should be stressed here that while the current ATcT value for HBr relies heavily on spectroscopic data, it is, at the same time, still entirely consistent (within the respective uncertainties) with the relevant calorimetric [54,55] and aqueous [56][57][58][59][60][61][62][63][64] thermochemical measurements.…”

Section: Thermochemistrysupporting

confidence: 52%

Inhibition of hydrogen oxidation by HBr and Br2

Dixon‐Lewis

Marshall

Ruščić

et al. 2012

Combustion and Flame

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The high-temperature bromine chemistry was updated and the inhibition mechanisms involving HBr and Br 2 were re-examined. The thermochemistry of the bromine species was obtained using the Active Thermochemical Tables (ATcT) approach, resulting in improved data for, among others, Br, HBr, HOBr and BrO. Ab initio calculations were used to obtain rate coefficients for selected reactions of HBr and HOBr, and the hydrogen/bromine/oxygen reaction mechanism was updated. The resulting model was validated against selected experimental data from literature and used to analyze the effect of HBr and Br 2 on laminar, premixed hydrogen flames. Our work shows that hydrogen bromide and molecular bromine act differently as inhibitors in flames. For HBr, the reaction HBr + H ⇀ ↽ H 2 + Br (R2) is rapidly equilibrated, depleting HBr in favor of atomic Br, which is the major bromine species throughout the reaction zone. The chain-breaking

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“…Most of the experimental osmotic coefficient data at 25°C were taken from the NIST databank, 30 except for HCl between 19 and 45 mol kg -1 . 31 In the databank, the data for the 1:1 electrolytes come from the compilation by Hamer and Wu 32 and those for sulfuric acid are from the work of Rard et al 33 The diameters of the free anions, σ 2 (kept constant versus concentration), and the diameter of H + ion at infinite dilution were taken from previous work: 9,14a 3.62 Å for Cl -, 3.40 Å for NO 3 -, 4.53 Å for ClO 4 -, 4.40 Å for SO 4 2-, 3.55 Å for OH -, and 5.04 Å for σ H + (0) . The charges of the species in the pair, z 3 and z 4 (with z 4 ) z 1 + z 2 -z 3 ) , were taken from a database, developed on the basis of DFT molecular structure calculations.…”

Section: Resultsmentioning

confidence: 99%

Ionic Solutions in the Binding Mean Spherical Approximation. Thermodynamics of Associating Electrolytes up to Very High Concentrations

2004

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A previous model, developed to describe the thermodynamic properties of associating electrolytes within the binding mean spherical approximation (BIMSA), is modified on the basis of a better representation of the pair. The ions are represented as charged hard spheres interacting through a sticky point potential, leading to the creation of pairs. In this version of the model, the species constituting the pair are allowed to have charges and sizes different from those of the free ions. New expressions for the osmotic and activity coefficients are proposed that account for these features. The equations were applied to fit the parameters in the model to osmotic data for a variety of aqueous solutions of inorganic acids, and for a base, NaOH, at 25°C up to the highest concentrations for which data are available. In all cases, accurate representations could be obtained up to very high concentrations, such as 28 mol kg -1 for nitric acid, 45 mol kg -1 for hydrochloric acid, and 29 mol kg -1 for NaOH. The case of sulfuric acid could be treated consistently in the concentration range 0-27.7 mol kg -1 by considering the equilibrium between sulfate and bisulfate ions. In all cases, the new model represents an improvement over the previous BIMSA model.

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Experimentelle Untersuchungen über das thermodynamische Verhalten konzentrierter Halogenwasserstoffsäuren

Cited by 60 publications

References 0 publications

Raman scattering studies of the condensed phase of the HIx feed of the sulfur-iodine thermochemical cycle

Raman scattering studies of the condensed phase of the HIx feed of the sulfur-iodine thermochemical cycle

Inhibition of hydrogen oxidation by HBr and Br2

Ionic Solutions in the Binding Mean Spherical Approximation. Thermodynamics of Associating Electrolytes up to Very High Concentrations

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