Liquid-Liquid Equilibrium For Extraction Separation Of Benzene And Cyclohexane Using Dimethyl Sulfoxide/(Dimethyl Sulfoxide And Potassium Thiocyanate)

Both of benzene and cyclohexane are important chemical products,and theirs application are very wide.In industrial,Benzene is prepared by catalytic hydrogenation of cyclohexane.Due to the reaction can not complete,separating benzene from the unreacted cyclohexane is important.The traditional distillation operation can not separate benzene from cyclohexane effectively.Therefore,more and more researchers pay attention to it.In order to solve the problem which the traditional distillation separation methods can't separate,researchers study a suitable separation technology.It is named liquid-liquid extraction separation technology.The key to this technology is that the choice of a suitable extraction solvent.The main contents of this paper is that:The compound solvent is preparated which is formed potassium thiocyanate and dimethyl sulfoxide.It is the extraction solvent to separate cyclohexane and benzene.The correction factor of the components is measured.The time when the system reaches the liquid-liquid equilibrium is measured.Equilibrium data of the ternary system cyclohexane+benzene+dimethyl sulfoxide and the quaternary system cyclohexane+benzene+dimethyl sulfoxide+potassium thiocyanate are measured at different temperatures.The selectivity coefficient of the solvent and distribution coefficient of the solute are calculated,and it is compared with some extractant.It is concluded that: the content of potassium thiocyanate in the co-solvent is closely related to selectivity coefficient of the solvent.As the mass fraction of potassium thiocyanate in the co-solvent becomes large,the selectivity coefficient becomes larger.The selectivity coefficient is certain affiliated with the operating temperature.As the temperature increasing,the selectivity coefficient of the solvent will be reduced.At 25?,the selectivity coefficient of the ternary solvent system is 4.1774~14.7549,the distribution coefficient is 0.6596~0.8000;At 30?,the selectivity coefficient of the ternary solvent system is 4.8171~14.2250,the distribution coefficient is 0.5689~0.7070;At 25?,the selectivity coefficient of the quaternary solvent is 6.1347~ 23.1559,the distribution coefficient is 0.0475~0.6261;At 30?,the selectivity coefficient of the quaternary solvent is 5.2762~22.6358,the distribution coefficient is 0.0639~0.5866.In order to analyze liquid-liquid equilibrium data intuitively,triangle phase diagrams of the ternary system and the quaternary system are plotted by origin8.5 at different temperatures.The experimental data of the ternary system are correlated by Othmer-Tobias equation and Hand equation.It is analyzed that the ternary system can be correlated well by these two equations.The experimental data of the ternary system and the quaternary system are correlated by the NRTL equation.And the root-mean-square Deviation between the measured data and the predicted data are calculated.The ternary system can be correlated and predicted well by this equation,but the quaternary system of the salt content of greater and lesser are dissatisfied.