Li Haoran

Prediction of Vapor-Liquid Equilibrium Data from C H Band Shift of IR Spectra in Some Binary Systems *

Abstract Prediction of vapor-liquid equilibrium (VLE) is extremely necessary to separate liquid mixture in chemical production, especially when the required experimental data are difficult to measure, or the measurement is not economical. The infinite dilution activities can be used to predict VLE. However, it needs both the ends of the activities that are difficult to obtain for many systems. In the present study, a new model is proposed for correlating the frequency shift of C—H stretching band of IR spectra over the whole concentration. Investigated mixtures include water/2-propanol, water/ N, N -dimethylformamide (DMF), water/methanol, water/ethanol, water/1,4-dioxane, and water/dimethylsulfoxide (DMSO) systems. Simultaneous correlations of C—H frequency shift and VLE data are made. Furthermore, the VLE data were predicted with satisfactory results by the parameters obtained from IR spectra coupled with one of the infinite dilution activity coefficients.

A Study of the Stability of Emulsion with Mixed Surfactants using Electrolytic Conductivity

Alcohols play an important role as cosurfactant in emulsions. The effects of cosurfactant chain length and concentration are discussed based on their particle size distribution (PSD) curves. A new model is established to determine the PSD by measuring the electrolytic conductivity of the emulsions.

Prediction of Vapor-Liquid Equilibria of Alcohol-Hydrocarbon Systems by 1H NMR and Azeotropic Point

Abstract With the energy parameters obtained from 1H nuclear magnetic resonance (NMR) chemical shifts data by local composition model and coupled with azeotropic point, the low-pressure vapor-liquid equilibrium is satisfactorily predicted for alcohol + hexane, alcohol + cyclohexane, and alcohol + benzene binary systems at different temperatures. The relationship between the spectroscopic information and thermodynamic property is presented.

Monte Carlo Simulation of the Interfacial Property of Surfactant–Cosurfactant–Oil–Water Systems

A square-lattice model of surfactant–cosurfactant–oil–water interfacial systems is developed in which oil and water act as solvent and occupy empty site and amphiphiles including surfactant–cosurfactant occupy chains of sites. The oil–water interface concentrations of amphiphiles calculated by Monte Carlo method show that for a certain surfactant–cosurfactant–oil–water system there is an optimum chain length of surfactant. And the interfacial concentration curves show that the amphiphile concentration affects the speed of the interface membrane reformation. The segment density profile of non-ionic surfactant systems is also investigated. The results showed that the depth of interface region is about twice the chain length. And the segment density is decreasing with the increasing of depth from interface for both oil–water region just like the error function. The partition coefficient of the surfactants in oil–water also vary for different surfactant chain length.