The Dissociation Constants of Nitrogen Tetroxide and of Nitrogen Trioxide

We have used in this work the crossover soft-SAFT equation of state to model nitrogen dioxide/dinitrogen tetraoxide (NO 2 /N 2 O 4 ), carbon dioxide (CO 2 ) and their mixtures. The prediction of the vapor -liquid equilibrium of this mixture is of utmost importance to correctly assess the NO 2 monomer amount that is the oxidizing agent of vegetal macromolecules in the CO 2 + NO 2 / N 2 O 4 reacting medium under supercritical conditions. The quadrupolar effect was explicitly considered when modeling carbon dioxide, enabling to obtain an excellent description of the vapor-liquid equilibria diagrams. NO 2 was modeled as a self associating molecule with a single association site to account for the strong associating character of the NO 2 molecule. Again, the vaporliquid equilibrium of NO 2 was correctly modeled. The molecular parameters were tested by accurately predicting the very few available experimental data outside the phase equilibrium. Soft-SAFT was also able to predict the degree of dimerization of NO 2 (mimicking the real NO 2 /N 2 O 4 situation), in good agreement with experimental data.Finally, CO 2 and NO 2 pure compound parameters were used to predict the vaporliquid coexistence of the CO 2 + NO 2 / N 2 O 4 mixture at different temperatures.Experimental pressure -CO 2 mass fraction isotherms recently measured were well described using a unique binary parameter, independent of the temperature, proving that the soft-SAFT model is able to capture the non-ideal behavior of the mixture.

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“…Figure 6 compares the calculated values with experimental data from Dunn et al [46] that also compared well with previous measurements [24,47].…”

Section: Pure Compounds Vle Modelingsupporting

confidence: 81%

Modeling the vapor–liquid equilibrium and association of nitrogen dioxide/dinitrogen tetroxide and its mixtures with carbon dioxide

Belkadi¹,

Llovell²,

Gerbaud³

et al. 2008

Fluid Phase Equilibria

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“…449] under the conditions of the present experiments. This is corroborated by a caleulation based on the equilibrium data of Verhoek and Daniels [14]. Th e fraction of nitrogen tetroxide in equilibrium with nitrogen dioxide, computed from the data of Giauque and Kemp [15], was found to be negligible under the conditions of the present experiments.…”

Section: Resultssupporting

confidence: 85%

Heat of combustion and formation of cyanogen

Knowlton¹,

Prosen²

1951

J. RES. NATL. BUR. STAN.

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Calorimetric measureme nts weTe made of the heat of combustio n of cyanogen in oxygen in a flame at consta nt press ure. The data y ielded the following value for the reaction of combu stion: C2N 2 (gas) + 202 (gas)= 2C02 (gas)+N2 (gas), !1FIc o at 25° C= -1095.97 ± 1.80 kj /mole = -261.94 ± 0.43 kcal/mole. Utili zing t he value for t he h eat of formation of carbon dioxide, the following value is given for the reaction of formation : 2C (solid, g raphi te) +~2 (gas) =C2X2 (gas) , MljO at 25° C=308.94 ± 1.80 kj /mole = 73 .84± 0.43 k ca1/mole.

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“…For example, Reamer and Sage [8] have done density measurements in the liquid-vapour coexistence region. Values of equilibrium constants in the gas phase as a function of temperature can be found in works of Verhoek and Daniels [9] or Chao et al [10]. James and Marshall [11] have determined equilibrium data for the liquid mixture and Redmond and Wayland [12] have been interested in equilibrium constant data for the nitrogen dioxide dissolved in organic solvents.…”

Section: Generalities On Cellulose Oxidation By Nitrogen Dioxidementioning

confidence: 99%