Related Experiment Video
Updated: Aug 21, 2026

Preparation of Binary and Ternary Deep Eutectic Systems
Published on: October 31, 2019
Thermodynamic Study of Amine-Based Deep Eutectic Solvents with EtOH
Fei Lin1,2, Yusi Shen1, Zhida Zuo1,2
1State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 210009, P. R. China.
None:
The densities and viscosities of the three amine-based deep eutectic solvents (DESs), i.e., [EmimCl]-[MEA], [BmimCl]-[MEA], and [HmimCl]-[MEA], mixed with ethanol (EtOH), were measured from 288.15 to 323.15 K, and their enthalpies of mixing were determined at 298.15 and 308.15 K. Negative excess molar volumes across the entire compositional range indicate significant volume contraction and enhanced molecular packing, and their temperature dependence suggests the dominance of packing effects over hydrogen-bonding. Viscosity deviations show a characteristic U-shaped composition dependence, reflecting disruption of the original DES hydrogen-bond network by EtOH. The enthalpy of mixing changes from positive to negative as the DES composition increases, revealing strengthened DES-EtOH interactions. The distinct composition-dependent trends observed for these three (DES + EtOH) systems indicate that variations in alkyl chain length modulate molecular packing and interaction strength, resulting in nonuniform ordering patterns across thermophysical properties. Compared to water, which strongly restructures the DES hydrogen-bond network and produces significant exothermic mixing effects, EtOH exerts a milder structural and thermodynamic impact. This work provides reliable thermodynamic data and mechanistic insight for the design and application of amine-based DESs.
Related Concept Videos
Physical Properties of Ethers
An ether molecule has a net dipole moment due to the polarity of C–O bonds. Subsequently, boiling points of ethers are lower than those of alcohols of comparable molecular weight and slightly higher than those of hydrocarbons of comparable molecular weight (Table 1).
Ethers can act as hydrogen bond acceptors, making them more water-soluble than hydrocarbons, but since ethers cannot act as hydrogen bond donors, they are much less soluble in water than alcohols. Ethers are considered...
Aldehydes and Ketones with Amines: Enamine Formation Mechanism
Titration in Nonaqueous Solvents
Physical Properties of Amines
Basicity of Heterocyclic Aromatic Amines
Aldehydes and Ketones with Amines: Imine Formation Mechanism
Imines are formed under mildly acidic conditions. A pH of 4.5 is ideal for the reaction.
If the pH is low or the solution is too acidic, the reaction slows down in the...

