Density, viscosity, surface tension, spectroscopic properties and computational chemistry of the 1, 4-butanediol + 1, 3-propanediamine-based deep eutectic solvent

A green 1,3-propanediamine (PDA)-based deep eutectic solvent (DES) was obtained using 1,4-butanediol (BDO) as the H bond donor (HBD), in which the basic physical and chemical properties of the binary system, such as density, viscosity and surface tension, were systematically studied under atmospheric pressure at T = 293.15–318.15 K. The excess Gibbs free energy (GE), apparent molar volumes (Vφ,1 and Vφ,2), partial molar volumes (V1 and V2) and isobaric thermal expansion coefficient (αp) of the binary system were also calculated. After that, the molecular configurations and intermolecular interaction mode of the BDO + PDA-based deep eutectic solvent were simulated and calculated by the Gaussian software; then, the intermolecular interaction between the BDO and PDA was explored by spectral technologies. Based on these discussions, it is confirmed that there is a hydrogen bond (HB) between the H atom of BDO and the N atom of PDA.