Low-temperature heat capacity and thermodynamic properties of 3,6-dichloro-2-methoxy-benzoic acid

The low-temperature heat capacity of 3,6-dichloro-2-methoxy-benzoic acid was precisely determined with an automated adiabatic calorimeter over the temperature range from 78 to 402 K. The sample was observed to melt at 388.15±0.03 K. The molar enthalpy and entropy of melting as well as the chemical purity of the substance were determined to be 22244±35 J mol−1, 57.31±0.09 J mol−1 K−1 and 99.31±0.02 mol%, respectively. The extrapolated melting temperature for the absolutely pure compound obtained from fractional melting experiments was 388.52±0.08 K.