The Research On Properties Of Cu(?)based Deep Eutectic Solvents For Separation Of Ethylene/ethane

Ethylene is the basic materials of the petrochemical industry,and the production reflects the economic strength of a country or a region.However,in the product process of ethylene,the systems in the form of olefin/paraffin mixtures always exist,and the separation of ethylene from mixtures is a key process in the petrochemical industry.Low temperature distillation process has high equipment investment and energyintensive separation process in industrial application.Therefore,a low energy consumption and economy separation technology need to be developed.Deep eutectic solvents(DES)can be designed,show low volatile solvent,100% atom economy,and the price is low.The copper based DES can be used for the absorption separation of ethylene/ethane,at the same time,also can be used as membrane liquid,applied to the supported liquid membrane for ethylene/ethane separation.In this work,we have designed and synthesized of four different DES: ChCl-G,ChCl-EG,[Bmim][ Cl]-EG and [Bmim][Cl]-G,and determined the viscosity,the four types of DES were characterized by ATR-FTIR and NMR,the formation of hydrogen bonds network within the eutectic system is analyzed;the existence of copper(I)was analyzed by MS characterization;SEM was used to characterize the SILM's preparation.The experimental was tested and investigated of the variety of DES,cuprous ion concentration,transmembrane pressure,temperature and time upon the separation selectivity and permeability coefficient.By means of absorption experiment and first-order absorption equilibrium model,the complexation reaction equilibrium constant,activity coefficient and effective cuprous ion concentration were analyzed.Supported liquid membrane separation experiment study found that the solution of cuprous chloride in ChCl-EG has great ethylene permeation flux and certain selectivity.Under the condition of 298 K and 1.1 bar,3 mol/L cuprous chloride dissolved in ChCl-EG,ethane permeation flux reached 122 barrer and selectivity is 12.5,exceed the upper bound curve of polymer membrane on ethane/ethylene separation;Ethylene selectivity and permeation was increased with cuprous salt concentration in DESs;CuCl/DESs show a long-time stability.Absorption experiments show that the four different types of DESs for ethylene/ethane separation consequence are consistent with permeability experiment,and the system with better performance have larger activity coefficient.Combined with the gases permeability coefficient,ethylene and ethane gas diffusion coefficient can be calculated.Characterization analyzed that hydrogen bond network within DES have positive correlation with cuprous activity.CuCl/DESs used in separation of ethylene/ethane,have the great ethylene separation selectivity,permeation,stability,higher cuprous ion activity,and so on.Therefore,CuCl/DESs systems have excellent application potential on olefin/paraffin separation.