Shi Ruifen, Zhou Fengyi, Chen Yu, Liu Zhenghui, Liu Shuzi, Mu Tiancheng
Department of Chemistry, Renmin University of China, Beijing, 100872, China.
Department of Chemistry and Material Science, Langfang Normal University, Langfang, 065000, Hebei, P. R. China.
Phys Chem Chem Phys. 2022 Aug 31;24(34):20073-20081. doi: 10.1039/d2cp01592g.
Deep eutectic solvents (DESs) are well-known as novel solvents due to their unique properties, which are indispensable for the development of green chemistry in the future. CoCl·6HO and NiCl·6HO-based DESs, which could be called magnetic DESs (MDESs) for short in view of their responsive behavior to an external magnetic field, have been widely used in many industrial applications, such as biomass treatment, electrolytes, and material preparation. For better application and full-scale development of these MDESs in various fields, eleven MDESs were prepared in this work by using CoCl·6HO and NiCl·6HO as hydrogen bond acceptors (HBAs) with alcohols, carboxylic acids and amides as hydrogen bond donors (HBDs), respectively. The intermolecular interactions between the components of MDESs were characterized FTIR, H NMR and DSC analysis. In addition, physicochemical properties including density, viscosity, conductivity, ionicity, pH values, surface tension, thermostability and solvatochromic parameters were investigated. All MDESs exhibit acid characteristics and have good conductivity comparable with ionic liquids (ILs) and other DESs used for electrolytes. The results show that stronger H-bonding networks in Ni-based MDESs make them have higher density, viscosity, polarity and surface tension values than Co-based MDESs. Moreover, all prepared MDESs possess a good conductivity behavior which could be comparable to that of common organic solvents and ILs. According to this work, we could better comprehend the behavior of Co/Ni-based MDESs and choose the appropriate one for particular applications.
深共熔溶剂（DESs）因其独特的性质而作为新型溶剂广为人知，这些性质对于未来绿色化学的发展不可或缺。基于CoCl₂·6H₂O和NiCl₂·6H₂O的DESs，鉴于其对外部磁场的响应行为，可简称为磁性DESs（MDESs），已广泛应用于许多工业领域，如生物质处理、电解质和材料制备。为了在各个领域更好地应用和全面开发这些MDESs，本工作以CoCl₂·6H₂O和NiCl₂·6H₂O作为氢键受体（HBAs），分别与醇类、羧酸和酰胺作为氢键供体（HBDs）制备了11种MDESs。通过傅里叶变换红外光谱（FTIR）、核磁共振氢谱（¹H NMR）和差示扫描量热法（DSC）分析对MDESs各组分之间的分子间相互作用进行了表征。此外，还研究了包括密度、粘度、电导率、离子性、pH值、表面张力、热稳定性和溶剂化显色参数等物理化学性质。所有MDESs均表现出酸性特征，并且具有与离子液体（ILs）和其他用于电解质的DESs相当的良好电导率。结果表明，镍基MDESs中较强的氢键网络使其比钴基MDESs具有更高的密度、粘度、极性和表面张力值。此外，所有制备的MDESs都具有良好的导电性能，可与常见有机溶剂和离子液体相媲美。根据本工作，我们可以更好地理解钴/镍基MDESs的行为，并为特定应用选择合适的MDESs。
