Heat capacities and thermodynamic properties of (S)-tert-butyl 1-phenylethylcarbamate

An N - tert -butyloxycarbonylated organic synthesis intermediate, ( S )- tert -butyl 1-phenylethylcarbamate, was prepared and investigated by means of differential scanning calorimetry (DSC) and thermogravimetry (TG). The molar heat capacities of ( S )- tert -butyl 1-phenylethylcarbamate were precisely determined by means of adiabatic calorimetry over the temperature range of 80-380 K. There was a solid–liquid phase transition exhibited during the heating process with the melting point of 359.53 K. The molar enthalpy and entropy of this transition were determined to be 29.73 kJ mol −1 and 82.68 J K −1 mol −1 based on the experimental C p – T curve, respectively. The thermodynamic functions, [ ] and [ ], were calculated from the heat capacity data in the temperature range of 80–380 K with an interval of 5 K. TG experiment showed that the pyrolysis of the compound was started at the temperature of 385 K and terminated at 510 K within one step.