Peng solubility

Lin T, Peng BX (1997) Synthesis and spectral characteristics of some highly soluble squarylium cyanine dyes. Dyes Pigm 35 331-338... 

The most important aspect of the simulation is that the thermodynamic data of the chemicals be modeled correctly. It is necessary to decide what equation of state to use for the vapor phase (ideal gas, Redlich-Kwong-Soave, Peng-Robinson, etc.) and what model to use for liquid activity coefficients [ideal solutions, solubility parameters, Wilson equation, nonrandom two liquid (NRTL), UNIFAC, etc.]. See Sec. 4, Thermodynamics. It is necessary to consider mixtures of chemicals, and the interaction parameters must be predictable. The best case is to determine them from data, and the next-best case is to use correlations based on the molecular weight, structure, and normal boiling point. To validate the model, the computer results of vapor-liquid equilibria could be checked against experimental data to ensure their validity before the data are used in more complicated computer calculations. 

Yinghuai Z, Peng AT, Carpenter K, Maguire JA, Hosmane NS, Takagaki M (2005) Substituted carborane-appended water-soluble single-wall carbon nanotubes New approach to boron neutron capture therapy drug delivery. J. Am. Chem. Soc. 127 9875-9880. 

To model the solubility of a solute in an SCF using an EOS, it is necessary to have critical properties and acentric factors of all components as well as molar volumes and sublimation pressures in the case of solid components. When some of these values are not available, as is often the case, estimation techniques must be employed. When neither critical properties nor acentric factors are available, it is desirable to have the normal boiling point of the compound, since some estimation techniques only require the boiling point together with the molecular structure. A customary approach to describing high-pressure phenomena like the solubility in SCFs is based on the Peng-Robinson EOS [48,49], but there are also several other EOS s [50]. 

Waters, E. J., Peng, Z., Pocock, K. F., and Williams, P. J. (1995). Proteins in white wine, I Procyanidin occurrence in soluble proteins and insoluble protein hazes and its relationship to protein instability. Aust. ]. Grape Wine Res. 1, 86-93. 

A serious test of mixture equations of state is shown to be their application for prediction of solubility of solutes in supercritical fluids (JJ. ). In the present report, we apply the Redl ich-Kwong and the Peng-Robinson equations of state for supercritical fluid extraction of solids and study the effect of choosing different mixing rules on prediction of solubility of solids in supercritical fluids -Figures 1-5. 

Nuclear weapons testing in the atmosphere introduced excess l4C that has proven to be an excellent tracer for processes that will be important in the uptake of fossil fuel CO2. For example, Peng (1986) mapped global uptake patterns of excess 14C and used these to calculate fossil fuel CO2 uptake by the oceans. His results indicate that about 10% of the fossil fuel CO2 is "missing". In the next chapter we will discuss the possibility that this missing CO2 may be the result of dissolution of highly soluble magnesian calcites from shallow water sediments. Also, Feely and... 

The experimental data are correlated with equation of state models. The calculation of binary phase equilibrium data for FAEE is commonly based on the Peng-Robinson-equation-of-state, Yu et al. (1994). Up to now only the solubility of the oil components in the solvent has been subject of various studies. No attention was paid to a correlation of ternary data. The computation of ternary or multicomponent phase equilibrium is the basis to analyse and optimise the separation experiments. 

The good agreement between experimental and calculated values is pointed out by the average absolute deviation, AAD. The results demonstrate the possibility to compute the solubility as well as the partition coefficients with the Peng-Robinson-equation of state and a mixing rule with two interaction parameters. 

Regarding the solid solubility, the EOS influence is inconclusive (for some mixing rules Peng-Robinson was the best, while for others ones, Soave) ... 

Solubility of toluene in SC CO2 can be found in the literature [8]. In a previous study in our laboratory, the solubility of DCB in SC CO2 was measured by [9] and was thus available. Figure 1 gives the solubilities (mol fraction) of DCB in SC CO2 vs pressure calculated for 3 temperatures using the Peng-Robinson EOS with an interaction parameter ki2 = 0.1175... 

Calculations of the solubility with a modified Peng-Robinson-EOS lead to remarkably lower equilibrium pressures for the given temperature ranges. The reason for this effect is, that the calculations are done for two-component systems. The paraffin used for the measurements and the production of the workpieces, however, is a mixture of homologue n-alkanes, so the calculation should be done for a multicomponent system. Up to now it was not possible to find a set of thermodynamic data, which represent this n-alkane mixture and lead to two-component-calculation results according to the measurements. 

Figure 6 The solubility of various gases in seawater as a function of temperature (Adapted from Broecker and Peng, 19827 )...

In all cultivars of V. vinifera studied so far, thaumatin-like proteins and chitinases are the major soluble components of grapes (Peng et al. 1997 Pocock et al. 1998,2000 Tattersall et al. 1997). The predominance of these PR proteins was clear at all stages of berry development following vdraison (Pocock et al. 2000). Importantly, as the concentration of these proteins in the berries continually increases... 

The predictive method suggested in this paper allows one to calculate the solubility of a solid in a binary mixture of SC fluids. The solubilities of three solids were predicted using only experimental data regarding the solubilities in the constituent binary mixtures (solid/SC fluid and solid/SC entrainer). Very good agreement was found between the experimental and predicted solubilities. For the solubilities of naphthalene and benzoic acid, the prediction of Eq. (42) provided even better agreement than the correlation [2] of experimental data based on the Peng-Robinson EOS with parameters determined from ternary data. 

For the prediction of the mixed-gas solubilities from the solubilities of the pure individual gases, the pressure dependence of the binary parameters ku is needed. The Peng—Robinson EOS was used to determine the binary parameters ku. The binary interaction parameter qi2 in the van der Waals mixing rule was taken from ref 28, where it was evaluated for the water-rich phases of water—hydrocarbon and water—carbon dioxide binary mixtures. The calculated binary parameters ku are listed in Table 1. One should note that, as expected for a liquid phase, the above parameters are almost independent of pressure, in contrast to their dependence on pressure in the gaseous phase near the critical point,... 

FIGURE 10 The solubility of C. I. Disperse Orange 30 dye in supercritical carbon dioxide as a function of pressure. Lines are calculated with Peng-Robinson equation of state (Equation 12). (From Baek, J.-K., Kim, S., Lee, G.-S., and Shim, J.-J., Korean J. Chem. Eng., 21(1), 230-235, 2004.)... 

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