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 10 6 cycles per second. In addition to the large increase in the dielectric constant within solid CH 3 OH at 159.6°K., there is evidence of a further, gradual transition at about 155°K. Similar changes in CH 3 OD 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 CH 3 OD are a little lower than those of CH 3 OH, 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).