1-丁基-3-甲基咪唑氯盐-水和2，6-二甲氧基苯酚混合物中分子相互作用的衰减全反射红外光谱研究

Molecular interactions of the ternary mixtures of 1-butyl-3-methylimidazolium chloride ([C₄C₁im]Cl)-water-2,6-dimethoxyphenol (2,6-DMP, a phenolic monomer lignin model compound) were investigated in comparison with the [C₄C₁im]Cl-water binary systems through attenuated total reflection infrared spectroscopy. Results indicated that the microstructures of water and [C₄C₁im]Cl changed with varying mole fraction of [C₄C₁im]Cl (^xIL) from 0.01 to 1.0. This change was mainly attributed to the interactions of [C₄C₁im]Cl-water and the self-aggregation of [C₄C₁im]Cl through hydrogen bonding. The band shifts of C-H on imidazolium ring and the functional groups in 2,6-DMP indicated that the occurrence of intermolecular interactions by different mechanisms (i.e., hydrogen bonding or π-π stacking) resulted in 2,6-DMP dissolution. In the case of ^xIL=0.12, the slightly hydrogen-bonded water was fully destroyed and [C₄C₁im]Cl existed in the form of hydrated ion pairs. Interestingly, the maximum 2,6-DMP solubility (238.5 g/100 g) was achieved in this case. The interactions and microstructures of [C₄C₁im]Cl-water mixtures influenced the dissolution behavior of 2,6-DMP.