Dielectric Constant of Hydrogen-Bonded Liquids. I. Cyanoacetylene

Abstract

The dielectric constant of cyanoacetylene has been determined over the normal liquid range: ε (T) = (71 000/T) —170. Analysis of the data in terms of a hydrogen-bonded linear polymer yields: ΔH = —2.80 kcal; ΔS = —15.8 eu per mole of hydrogen bond. The vapor pressure of solid and liquid HCCCN has been measured. Molar enthalpies and entropies of fusion and vaporization are: 3.38 and 6.72 kcal; 12.1 and 21.3 eu, respectively. Hydrogen bonding in this and similar systems is discussed.