Thermodynamic properties and intermolecular hydrogen bonding in 1,2-Propanediol/Diethylenetriamine Mixtures: Experimental and computational insights

This study investigates the thermodynamic properties and intermolecular hydrogen transfer behavior in binary mixtures of 1,2-propanediol (1,2-PD) and diethylenetriamine (DETA). Experimental measurements of density, sound velocity, and viscosity reveal significant interactions between the hydroxyl group of 1,2-PD and the amino group of DETA, leading to non-ideal mixing behaviors. The excess molar volumes, apparent molar volumes, and viscosity deviations show clear evidence of intermolecular hydrogen bonding. Theoretical calculations using density functional theory (DFT) further support the formation of hydrogen bonds, with optimized molecular structures and pathways confirming a concerted hydrogen transfer mechanism. The study identifies the pathway for hydrogen transfer and provides insights into the thermodynamic and structural changes occurring in this mixture. These findings enhance our understanding of hydrogen transfer processes between alcohol and amine and offer valuable knowledge for the design of materials with tailored properties in industrial and research applications.