Study On The Basic Properties Of Ordered Molecular Aggregates Of Imidazole Ionic Liquid/oleic Acid

The imidazole ionic liquid has excellent physical and chemical properties,and can be used as a solvent or a surfactant depending on the cation chain length and the anion species.Oleic acid has good biocompatibility and degradability,and the ordered aggregates that contain oleic acid can be applied to the pharmaceutical and food industries.By combining the characteristics of imidazole ionic liquids and oleic acid to construct ordered aggregates of these two compounds,the application fields of these two compounds can be broadened.In this paper,the formation process of lyotropic liquid crystals and microemulsions of molecular ordered aggregates which contain imidazole ionic liquid and oleic acid were analyzed preliminarily,and the phase behaviors,structural properties and electrical conductivities of the aggregates were studied.The formation of high-grade structures of imidazole ionic liquids and oleic acid is presented.The system is regulated to achieve pre-designed properties.The effects of intermolecular interactions on the formation of high-order structures and their stability are preliminarily discussed.Three hydrophilic imidazole ionic liquids[BMim]Cl,[BMim]BF₄ and[EMim]BF₄ were combined with TX-100,oleic acid and water,respectively,to prepare three lyotropic liquid crystal systems with high electrical conductivity.The liquid crystal and non-liquid crystal regions of the three systems at normal pressure and different temperatures were divided by drawing a pseudo-ternary phase diagram.The content of[BMim]Cl in TX-100/oleic acid/water/[BMim]Cl liquid crystal system increases in the range of 0¹3.3wt%,and the structure of liquid crystal changes from layered to hexagonal,and the lattice parameters are all at the nanometer level,and the liquid crystal is hexagonal,the inner core of the cylinder is an aqueous ionic liquid solution.The phase behavior of the three liquid crystal systems shows that the greater the polarity of the ionic liquid,the smaller the range of lyotropic liquid crystals formed by the system is affected by the aqueous ionic liquid solution.For the same system,the larger the mass ratio of ionic liquid to water,the smaller the liquid crystal phase region that the system can form.As the temperature increases,the intermolecular hydrogen bonding in the system weakens,tending to form a non-liquid crystal mixture,and the liquid crystal region is reduced.Part of the liquid crystal in the liquid crystal region is a layered and hexagonal structure,and has corresponding rheological properties and good electrical conductivity.Two oleic acid-based ionic liquid microemulsions were prepared by using oleic acid as the non-polar phase,[BMim]BF₄ as the polar phase,and TX-100 and catalytically active ionic liquid[HMim]HSO₄ or[OMim]HSO₄ as surfactant.The conductance behaviors of the two systems were related to the structures of them.As the content of oleic acid in the system increased,the electrical conductivity of the O/W microemulsion increased,and the conductivity of the microemulsion with the bicontinuous structure decreased nonlinearly.The conductivity of the W/O microemulsion showed a linear decrease.Phase behavior studies have shown that these two oleic acid-based ionic liquid microemulsion systems have good temperature independence and thermal stability.The micro-reaction system of synthesis of butyl oleate was constructesd by microemulsion with[HMim]HSO₄ as catalyst.The yield of butyl oleate was 92.5%.