Dielectric Relaxation Mechanism in Some Alkanethiols. II

Abstract

Dielectric constant and dielectric loss (ε′ and ε″) of four liquid alkanethiols have been measured at four microwave frequencies at 0, 20, 40, and 60°C. The normalized plots of ε′/(ε0−ε∞) vs (ε′−ε∞)/(ε0−ε∞) for all four liquids are skewed arcs. The characteristic relaxation time (τ0) and empirical parameter (β) have been calculated from these plots. The dielectric behavior of alkanethiols is more like alkyl halides than alcohols. The main mechanism which is responsible for asymmetric distribution of relaxation time in the liquid state appears to be multiple relaxation processes.

Some physical properties of ten alkanethiols as a function of temperature

“…Physical properties of alkanethiols (RSH) are of interest as they are similar in structure to alcohols (ROM), which have been extensively studied in order to investigate the effect of hydrogen bonding. Krishna]i et al (6)(7)(8) have studied dielectric relaxation behavior of alkanethiols and found that the hydrogen bonding Is almost absent or too small to be detected by dielectric measurements in these compounds. The present study was undertaken to measure low frequency dielectric constants, viscosities, densities, and refractive indices of ten alkanethiols, namely, propane-1-thiol, butane-1-thiol, butane-2-thiol, 2-methylpropane-2-thiol, pentane-1-thiol, 2-methylbutane-2-thiol, hexane-1thiol, heptane-1-thiol, octane-1-thiol, and 2-methyloctane-2thiol in the temperature range 0-60 °C.…”