Just Grundnes

Pressure effects on conformational equilibria. Difference in volume between conformers of 1,1,2‐trichloroethane

The effect of pressure on the equilibrium between conformers of 1,1,2‐trichlorocyclohexane has been studied using infrared spectra obtained with the diamond anvil cell. Changes in relative intensities of infrared bands show that the population of the more polar conformer (Cs symmetry) increases relative to that of the less polar conformer (C1 symmetry) with increasing pressure. Volume differences for converting the less polar to the more polar conformer are −3.8 cm3/mol in pure liquid and −1.8 cm3/mol in CS2 solution. These results are in agreement with values calculated by K. R. Crook and E. Wyn‐Jones [J. Chem. Phys. 50, 3445 (1969)].

High Pressure Infrared Studies of Liquids with the Diamond Anvil Cell

The diamond anvil cell (DAC) has been used in many high pressure studies. Its simplicity and convenience make it an attractive tool for infrared, Raman, and visible-ultraviolet investigations of condensed phases. Unfortunately, although quite large pressures can be applied to samples in the cell, it is difficult to determine pressure values with reliability. This note describes our experience in using the DAC for quantitative infrared studies of liquids at pressures in the 0 to 12 kbar range.