Determination And Correlation Of Liquid-liquid Phase Equilibrium For Ternary Mixtures Of Formamide(or Ethylene Glycol, Monoethanolamine, Dilute Sulphuric Acid)+Quinoline+Diphenyl

Quinoline is also known as benzopyridine. It is prone to electrophilic addition reaction, widely used in organic synthesis and pharmaceutical preparation, etc., and also a good organic solvent. It can be extracted from coal tar or synthesized by aniline. However, the synthesis method is too complex, the raw material is expensive, not suitable for industrial production. But also the discharge of waste acid increases the post processing, so that the cost of production is further increase. On the other hand, the quinoline content in the accumulation of coal tar can reach 10% ~ 20%. But, the coal tar is often processed seldom or as raw material of carbon black on sale, which result in the unreasonable utilization of resources. Therefore, it is a good method that quinoline is extracted from coal tar. In the industrial production, the combination of distillation and extraction method is adopted to extract quinoline. The selection of extraction agents is very important.Coal tar also contains a variety of organic compounds, such as naphthalene compounds, diphenyl and fluorene, etc.. Therefore, this thesis discussed that quinoline and biphenyl as the original solution, four solvents were selected as the extraction agent and then the liquid phase equilibrium of the ternary system was studied. The four types of extraction agents are formamide, ethylene glycol(EG), monoethanolamine(MEA), dilute sulfuric acid(DSA). When extracting agent is added into the original solution for performing extraction operation, it will make the mass and heat transfer between the two phases to achieve balance. The liquid-liquid phase equilibrium data of the four systems are determined by the experiment, and it can be used as the basic data for extraction operation. Also the most effective extracting agent is judged according to the experimental data.In this thesis, we mainly study the liquid-liquid equilibrium(LLE) of four ternary-mixture systems. In order to obtain basic data on calculating theoretical extraction stage, solubility and liquid-liquid equilibrium(LLE) data were determined for mixtures of formamide(or EG or MEA or DSA) + quinoline + diphenyl at 344.15 K and 1 atm. And draw out ternary phase diagrams basic on the experimental data. Then the Othmer-Tobia equation and activity coefficient models of NRTL and UNIQUAC were used to correlate the experimental data. The linear correlation coefficient of experimental data correlated by Othmer-Tobia equations are close to 1. Meanwhile, binary interaction parameters of activity coefficient models were determined by the objective function. And then, calculated LLE data were obtained. The two activity coefficient models can well simulate to the four systems of the LLE according to the mean relative standard deviation(mrsd). In addition, distribution coefficients and selectivity values, derived from the tie line data, indicate that dilute sulphuric acid is suitable to the liquid–liquid extraction of quinoline from diphenyl, comparatively.