Microstructure In Liquid-liquid Systems And Its Application In Synthesis Of Hierarchical Porous Materials

The liquid-liquid mixture system can usually be a single-phase,two-phase or multi-phase coexistence system according to its degree of mutual solubility,and its chemical structure will change with the composition of the system,the composition of the mixture,the temperature and pressure.The study of the phase behavior of different systems has received extensive attention because of the great significance in both theoretical and practical viewpoints.However,the variation of microstructures in liquid solutions near the phase boundary is not clear.In this paper,the formation of nano-domains in solution is studied when the components in the single-phase region of the liquid-liquid mixed solution are close to the phase boundary.In this paper,four groups of liquid-liquid ternary partially miscible mixed systems composed of different hydrocarbons were selected as research objects,including n-hexane/ethanol/water,cyclohexane/ethanol/water,n-heptane/ethanol/water and n-octane/ethanol/water.The microstructure of the solution in the single-phase region of the four hydrocarbon mixed systems was investigated.It is found that there exist nanodomains in a solution near the phase boundary and the size increases abruptly as the composition approaches the phase separation point.Based on the above findings,a new method of designing and synthesizing hierarchical porous materials by using the variation of solution phase separation microstructure is proposed.Ionic liquid is a green solvent with many characteristics.It provides a broad space for the synthesis of new porous materials.The molecular aggregation and solution microstructure research in ionic liquid solution system is of great significance.Metal-organic frameworks?MOFs?materials are an important class of pore materials,but generally MOFs have only micropores,which limit their application to a large extent.In this paper,the hierarchical porous Cu-BTC MOF was synthesized in the ionic liquid 1-hexyl-3-methylimidazolium hexafluorophosphate?[Hmim][PF₆]?/ethanol system under normal temperature and pressure conditions.It is found that aggregation behavior exists in this system,and the pore properties of the catalytic material can be regulated by changing the mass fraction of the ionic liquid/ethanol and the mass of the ligand.The synthesized hierarchical porous Cu-BTC MOF has good catalytic activity for the oxidation of alcohols to aldehydes and can be recycled.