Vapor Pressure, Vaporization Enthalpy, Standard Enthalpy of Formation and Standard Entropy of n-Butyl Carbamate

The vapor pressures of n-butyl carbamate were measured in the temperature range from 372.37 K to 479.27 K and fitted with Antoine equation. The compressibility factor of the vapor was calculated with the Virial equation and the second virial coefficient was determined by the Vetere model. Then the standard enthalpy of vaporization for n-butyl carbamate was estimated. The heat capacity was measured for the solid state (299.39–324.2 K) and liquid state (336.65–453.21 K) by means of adiabatic calorimeter. The standard enthalpy of formation ΔfHθ[crystal (cr),298.15 K] and standard entropy Sθ(crystal,298.15 K) of the substance were calculated on the basis of the gas-phase standard enthalpy of formation ΔfHθ(g,298.15 K) and gas-phase standard entropy Sθ(g,298.15 K), which were estimated by the Benson method. The results are acceptable, validated by a thermochemical cycle.

Graphic abstractThe vapor pressures of n-butyl carbamate (BC) were measured in the temperature range from 372.37 K to 479.27 K. The plot of lgp of n-butyl carbamate against lgp′ of ethyl butyrate in the temperature range shows that lgp/lgp′ is constant and independent of temperature, which is used to calculate ΔvapHθ(298.15 K) of BC by the Othmer method.Figure optionsDownload full-size imageDownload as PowerPoint slide