Synthesis Of Ester-Containing Ionic Liquids And The Interaction In Water

Compared with traditional ionic liquids (ILs), Ester-containing ionic liquids have excellent biodegradation, and show a broad prospect in practical industrial applications. So it becomes one of the focuses in recent years. Without the physical and chemical properties of ionic liquids, Ester-containing ionic liquids can't be applied well in industry. However, few studies have been done in this field, which restrict the further development and application of this kind of ionic liquids. According to this, the physical and chemical properties and aggregation behavior for Ester-containing ILs were studied in this work. The results can give a reasonable explanation for the unusual phenomenon in ILs-containing system, and can also provide theoretical basis for the molecular design and industrial applications of ILs. As a part of the project supported by the National Natural Science Foundation of China (NO. 20873036), the major content of the present work is as follows:1. The 24 kinds of Ester-containing ionic liquids [mimCH₂COOCnH_{2n +1}]Cl (n = 1 8, 3-i, 4-i, 4-s, 6-c) and [pyCH₂COOCnH_{2n +1}]Cl (n = 1 8, 3-i, 4-i, 4-s, 6-c) have been synthesized and purified. The 22 kinds of ionic liquids were first reported.2. Densities for 22 kinds of aqueous Ester-containing ionic liquids solutions have been determined using Anton Parr DMA60/602 digital density meter at 298.15 K. Based on these data, the apparent molar volumes and the standard partial molar volumes have been calculated in water. It is shown from the result that the standard partial molar volumes increased as the alkyl chain of ionic liquids becomes longer. The structure of branched-chain on the side chain has little effect on standard partial molar volumes.3. The conductivities for 9 kinds of aqueous Ester-containing ionic liquids solutions [mimCH2COOCnH2n +1]Cl (n = 1 6, 3-i, 4-i, 6-c) have been precisely measured using Wayne-Kerr 6430B automatic balance bridge type digital conductivity meter at 298.15 K. The values of limiting molar conductivities (Λm0) and association constant (KA) for these ionic liquids were calculated. It is shown that limiting molar conductivity of Ester-containing ionic liquid decreases with the increasing of the chain length. Its effective volume is the main factor to determine to the moving speed of ionic liquids.4. Densities and conductivities for aqueous Ester-containing ionic liquids solutions were measured at 298.15 K. With the aid of the pseudophase model of micellization, the critical aggregation concentrations and the related physicochemical properties of the ILs have been calculated. The results show that the aggregation of ILs is tuned by adjusting the alkyl chain. The alkyl chain-ion inductive and hydrocarbon-hydrocarbon interactions were the main driving force for the aggregation.