Dielectric Relaxation of Some Aliphatic Ketones in Cyclohexane Solution

Dielectric constant and loss data are presented for cyclohexane solutions of 2-hexanone, 2-, 3-, 4-, and 5-nonanone, 2- and 4-decanone, 2-, 4-, and 8-pentadecanone, and 2- and 10-nonadecanone in cyclohexane at up to nine frequencies between 1.5 and 145 GHz at 25°C. The absorption for each system may be represented by a Cole—Cole distribution. For the 2-alkanones, all the nonanones, and 4-decanone, dipole orientation occurs predominantly by intramolecular motion. Rotational orientation of the molecule as a whole appears to make an appreciable contribution also when the dipole is located away from the chain end in the longer molecules.