Time domain reflectometry studies on benzaldehyde–ethanol binary solutions

Time domain reflectometry (TDR) study has been carried out on benzaldehyde (PhCHO), ethanol (EtOH) and their binary solutions in the frequency range from 10 MHz to 25 GHz at different temperatures viz., 288.15, 293.15, and 298.15 K. The complex permittivity spectra have been fitted to the Debye function. Dielectric constant (ε0) vs mole fraction (X2, of EtOH ) graph shows that PhCHO-EtOH H-bond interactions are weaker in the solutions for which 0.0≤X2≤0.50 than in the solutions with 0.50<X2≤1. The relaxation time τ values suggest that lower order EtOH multimer involves in heteromolecular H-bond in PhCHO rich solutions. Antiparallel orientation of dipoles in pure PhCHO continues to exist upto X2 = 0.69. The smaller deviation of gf,εE/fB/ΔFE from the ideal behavior specifies that the PhCHO interactions is weaker than EtOH-EtOH interactions. The well-known cyclic and linear dimers of PhCHO and cyclic multimers of EtOH is confirmed by geff and enthalpy values. The average number of hydrogen bonds have been analyzed using Luzar model calculations. EtOH multimers are found to be vulnerable on dilution by PhCHO. It appears that EtOH exhibits similar behavior in the solutions with aromatic carbonyl compounds. © 2024 Elsevier B.V.