THE DIELECTRIC PROPERTIES OF METHANOL AND METHANOL-d

Abstract

The dielectric properties of methanol and methanol-d were examined between liquid nitrogen and room temperature at frequencies between 40 and 106 cycles per second. In addition to the large increase in the dielectric constant within solid CH3OH at 159.6°K., there is evidence of a further, gradual transition at about 155°K. Similar changes in CH3OD occur at 163.2° and about 157°K. Dispersion processes within the solid are discussed in terms of misaligned crystallites and polarization at the interfaces between crystallites and between regions of solid and liquid. Conductance maxima near 130°K. are tentatively related to the methanol–water eutectic. Static dielectric constants of liquid CH3OD are a little lower than those of CH3OH, while relaxation times over a limited temperature range above the freezing point are some 35% higher; the activation energies for dielectric relaxation of the two molecules in the liquid state are approximately the same (3.5 kcal./mole).