Hydrogen Bonding in 1-Propanol-Ethanol Binary Mixture: Experimental and Modeling Approaches

Hydrogen bonds between the constituent molecules determine the physical properties of binary liquids. In this work, we explore the nature of hydrogen bonding in ethanol-propanol system through experimental and computational techniques. The refractive index, dielectric spectroscopy and infrared spectroscopy along with molecular dynamic simulations of 1-propanol-ethanol binary system over the entire concentration range are reported here. The excess static permittivity and excess relaxation time shows the evidence of hydrogen bonded multimer structures. The deconvoluted OH peaks from IR spectra indicate the presence of trimers, tetramers and pentamers. The linear decrease in refractive index indicates the absence of caged structures. Molecular Dynamics simulations confirm the presence of the multimers and the absence of caged structures. Radial distribution function shows the binary mixtures exhibit no structural change throughout the concentration range. We also examine the H-bonding networks present in these systems via graph theoretic analysis.