Based on a modified van der Waals model, in which the excluded volume is expressed as a linear function of density, the internal pressure and the physical contribution of two - dimensional solubility parameter suggest...Based on a modified van der Waals model, in which the excluded volume is expressed as a linear function of density, the internal pressure and the physical contribution of two - dimensional solubility parameter suggested by Bagley et al. can be expressed as functions of density and a size dependent parameter A. A group contribution method for estimating parameter A and then the solubility parameter has been developed. Average relative deviation of the predicted solubility parameters in comparison will the experimental values for more than sixty liquids including non- polar and polar species as well as those with strong hydrogen bonding is 0.8%. Further correlation with topological indices of molecules makes this method applicable to various isomers of saturated alkanes. Average relative deviation of prediction for 34 saturated alkanes is only 0.6%.展开更多
The original van Laar's theory has been modified. The internal pressures of components and mixture are expressed by Frank's relation and the excess entropy for mixing of components is also considered. A new ac...The original van Laar's theory has been modified. The internal pressures of components and mixture are expressed by Frank's relation and the excess entropy for mixing of components is also considered. A new activity coefficient equation, which can be satisfactorily applied to polymer solutions, is obtained. The calculated results for the VLE of 179 polymer solutions show that the accuracy of fit is evidently superior to UNIQUAC equation.展开更多
The modified van der Waals’model which has only one molecular size-dependent parameter is used to calculate the internal pressures of liquids.It is found that the model parameter has very good linear relation with th...The modified van der Waals’model which has only one molecular size-dependent parameter is used to calculate the internal pressures of liquids.It is found that the model parameter has very good linear relation with the molar volume of liquids at normal boiling point.A group contribution method is established for the molar volume of liquids at normal boiling point.Therefore the internal pressures of various liquids can be predicted.On the basis of the generalized Gibbs free energy model for mixing of liquids,proposed by our previous work,a new solubility parameter had been defined,which is equal to the ratio of the cohesive energy density with the square root of internal pressure.This definition is more strict and its range of application is more exten sive than classical Hildebrand solubility parameter.In present work,the values of new solubility parameter for 170 solvents at 298.15 K are obtained.展开更多
文摘Based on a modified van der Waals model, in which the excluded volume is expressed as a linear function of density, the internal pressure and the physical contribution of two - dimensional solubility parameter suggested by Bagley et al. can be expressed as functions of density and a size dependent parameter A. A group contribution method for estimating parameter A and then the solubility parameter has been developed. Average relative deviation of the predicted solubility parameters in comparison will the experimental values for more than sixty liquids including non- polar and polar species as well as those with strong hydrogen bonding is 0.8%. Further correlation with topological indices of molecules makes this method applicable to various isomers of saturated alkanes. Average relative deviation of prediction for 34 saturated alkanes is only 0.6%.
基金Supported by the National Natural Science Foundation of China(No.29376236).
文摘The original van Laar's theory has been modified. The internal pressures of components and mixture are expressed by Frank's relation and the excess entropy for mixing of components is also considered. A new activity coefficient equation, which can be satisfactorily applied to polymer solutions, is obtained. The calculated results for the VLE of 179 polymer solutions show that the accuracy of fit is evidently superior to UNIQUAC equation.
文摘The modified van der Waals’model which has only one molecular size-dependent parameter is used to calculate the internal pressures of liquids.It is found that the model parameter has very good linear relation with the molar volume of liquids at normal boiling point.A group contribution method is established for the molar volume of liquids at normal boiling point.Therefore the internal pressures of various liquids can be predicted.On the basis of the generalized Gibbs free energy model for mixing of liquids,proposed by our previous work,a new solubility parameter had been defined,which is equal to the ratio of the cohesive energy density with the square root of internal pressure.This definition is more strict and its range of application is more exten sive than classical Hildebrand solubility parameter.In present work,the values of new solubility parameter for 170 solvents at 298.15 K are obtained.
