Dielectric relaxation dynamics and hydrogen bonding interactions reveal the molecular association mechanisms in binary mixtures of 3-chloroaniline and 1-methoxy-2-propanol at 298 K

Abstract

The complex dielectric spectra of binary mixtures of 3-chloroaniline (3-CA) and 1-methoxy-2-propanol (PGME) were measured at 298 K over a frequency range from 10 MHz to 30 GHz for eleven different volume compositions. The dielectric parameters, namely the complex dielectric permittivity spectra (ε′) and complex dielectric loss spectra (ε″), were analyzed using the Havriliak-Negami model, which revealed Cole-Davidson-type relaxation. The static dielectric constant (ε0) and relaxation time (τ) were determined. The dielectric response of all samples at 298 K was satisfactorily explained by a single relaxation mechanism. Additionally, the effective Kirkwood correlation factor (𝑔eff), Bruggeman factor (fB) and excess dielectric parameters were evaluated to investigate molecular interactions. Strong specific interactions were observed between the amino group (-NH2) of 3-CA and the alcoholic group (-OH) of PGEE through hydrogen bonding, resulting in significant non-ideality in mixing. These findings demonstrate the effectiveness of dielectric spectroscopy in elucidating molecular interactions and relaxation phenomena in binary liquid mixtures of 3-CA and PGME.