scholarly journals Technical note: Estimating aqueous solubilities and activity coefficients of mono- and <i>α</i>, <i>ω</i>-dicarboxylic acids using COSMO-RS-DARE

2020 ◽  
Author(s):  
Noora Hyttinen ◽  
Reyhaneh Heshmatnezhad ◽  
Jonas Elm ◽  
Theo Kurtén ◽  
Nønne L. Prisle
Keyword(s):  
Activity Coefficients ◽  
Equilibrium Constants ◽  
Hydrate Formation ◽  
Dicarboxylic Acids ◽  
Water Systems ◽  
Technical Note ◽  
Monocarboxylic Acids ◽  
Binary Solutions ◽  
Experimental Activity ◽  
Aqueous Solubilities

Abstract. We have used the COSMOtherm program to estimate activity coefficients and solubilities of mono- and α, ω-dicarboxylic acids, and water in binary acid-water systems. The deviation from ideality was found to be larger in the systems containing larger acids than in the systems containing smaller acids. We found a better agreement between estimated and experimental activity coefficients of monocarboxylic acids when the water clustering with a carboxylic acid and itself was taken into account using the dimerization, aggregation and reaction extension (COSMO-RS-DARE) of COSMOtherm. Based on effective equilibrium constants of different clustering reactions in the binary solutions, acid dimer formation is more dominant in systems containing larger dicarboxylic acids (C5–C8), while for monocarboxylic acids (C1–C6) and smaller dicarboxylic acids (C2–C4), hydrate formation is more favorable, especially in dilute solutions.

scholarly journals Technical note: Estimating aqueous solubilities and activity coefficients of mono- and <i>α</i>,<i>ω</i>-dicarboxylic acids using COSMO<i>therm</i>

2020 ◽  
Vol 20 (21) ◽  
pp. 13131-13143
Author(s):  
Noora Hyttinen ◽  
Reyhaneh Heshmatnezhad ◽  
Jonas Elm ◽  
Theo Kurtén ◽  
Nønne L. Prisle
Keyword(s):  
Activity Coefficients ◽  
Equilibrium Constants ◽  
Hydrate Formation ◽  
Dicarboxylic Acids ◽  
Aqueous Solubility ◽  
Technical Note ◽  
Acid Water ◽  
Monocarboxylic Acids ◽  
Wide Range ◽  
Experimental Values

Abstract. We have used the COSMOtherm program to estimate activity coefficients and solubilities of mono- and α,ω-dicarboxylic acids and water in binary acid–water systems. The deviation from ideality was found to be larger in the systems containing larger acids than in the systems containing smaller acids. COnductor-like Screening MOdel for Real Solvents (COSMO-RS) underestimates experimental monocarboxylic acid activity coefficients by less than a factor of 2, but experimental water activity coefficients are underestimated more especially at high acid mole fractions. We found a better agreement between COSMOtherm-estimated and experimental activity coefficients of monocarboxylic acids when the water clustering with a carboxylic acid and itself was taken into account using the dimerization, aggregation, and reaction extension (COSMO-RS-DARE) of COSMOtherm. COSMO-RS-DARE is not fully predictive, but fit parameters found here for water–water and acid–water clustering interactions can be used to estimate thermodynamic properties of monocarboxylic acids in other aqueous solvents, such as salt solutions. For the dicarboxylic acids, COSMO-RS is sufficient for predicting aqueous solubility and activity coefficients, and no fitting to experimental values is needed. This is highly beneficial for applications to atmospheric systems, as these data are typically not available for a wide range of mixing states realized in the atmosphere, due to a lack of either feasibility of the experiments or sample availability. Based on effective equilibrium constants of different clustering reactions in the binary solutions, acid dimer formation is more dominant in systems containing larger dicarboxylic acids (C5–C8), while for monocarboxylic acids (C1–C6) and smaller dicarboxylic acids (C2–C4), hydrate formation is more favorable, especially in dilute solutions.

Limiting activity coefficients in dilute solutions of nonelectrolytes. II. Determination for polar–nonpolar and polar–polar binary mixtures, and the application of some solubility-parameter treatments

1986 ◽  
Vol 64 (1) ◽  
pp. 198-203 ◽  
Author(s):  
Shapour Afrashtehfar ◽  
Genille C. B. Cave
Keyword(s):  
Binary Mixture ◽  
Activity Coefficients ◽  
Vapor Phase ◽  
Solubility Parameter ◽  
Chromatographic Analysis ◽  
Dipole Interaction ◽  
The Other ◽  
Binary Solutions ◽  
Polar Components ◽  
Induced Dipole

Activity coefficients were determined at 293.15 K for the more dilute component in 24 binary solutions of nonelectrolytes, by gas-chromatographic analysis of the equilibrium vapor phase. One component of the binary mixture was either nitromethane, nitroethane, 1-nitropropane, 2-nitropropane, ethanenitrile, propanenitrile, ethyl ethanoate, or butyl ethanoate; and the other component was either heptane, 1-heptene, or 1,6-heptadiene.From the limiting activity coefficients of these components, some factors that affected their magnitude were identified. The values were also used to test the modifications of Prausnitz, Blanks, and Weimer, of Helpinstill and Van Winkle, and of Keller, Karger, and Snyder to the Scatchard–Hildebrand equation modified to accommodate polar components. In addition, the degree of constancy of the ratio of the dipole – induced dipole interaction parameter for a series of solutes in one solvent to that in another was considered.

scholarly journals Evaporation of sulphate aerosols at low relative humidity

2016 ◽  
Author(s):  
Georgios Tsagkogeorgas ◽  
Pontus Roldin ◽  
Jonathan Duplissy ◽  
Linda Rondo ◽  
Jasmin Tröstl ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Thermodynamic Properties ◽  
Sulphuric Acid ◽  
Activity Coefficients ◽  
Vapour Pressure ◽  
Equilibrium Constants ◽  
Cloud Chamber ◽  
Aerosol Dynamics ◽  
Sulphate Aerosols

Abstract. Here we explore the vapour pressure of sulphuric acid at very low relative humidity, where evaporation of sulphuric acid from particles can be important in the atmospheres of Earth and Venus. We performed experiments in the CLOUD chamber at CERN forming sulphuric acid particles via nucleation and then measuring evaporation versus temperature and relative humidity. We modelled the experiments with the ADCHAM model to constrain the thermodynamic properties governing the evaporation of sulphuric acid. ADCHAM includes a thermodynamics module coupled to an aerosol dynamics module. We derived the mole fractions and activity coefficients of H2SO4, HSO4−, SO42− and SO3 in the particles and then simulated the condensation and evaporation of H2SO4 and SO3. We constrained the equilibrium constants for the dissociation of H2SO4 to HSO4− (KH2SO4) and the dehydration of H2SO4 to SO3 (xKSO3). Our results suggest that particle shrinkage is mainly governed by H2SO4 evaporation, however, we cannot dismiss a contribution from SO3 evaporation. We conclude that KH2SO4 = 2–4 ∙ 109 mol ∙ kg−1 at 288.8 ± 5 K and xKSO3 ≥ 1.4 ∙ 1010.

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