Heat capacity anomaly near the lower critical consolute point of triethylamine–water

The heat capacity of the binary liquid mixture triethylamine–water has been measured near its lower critical consolute point using a scanning, adiabatic calorimeter. Two data runs are analyzed to provide heat capacity and enthalpy data that are fitted by equations with background terms and a critical term that includes correction to scaling. The critical exponent α was determined to be 0.107±0.006, consistent with theoretical predictions. When α was fixed at 0.11 to determine various amplitudes consistently, our values of A + and A− agreed with a previous heat capacity measurement, but the value of A+ was inconsistent with values determined by density or refractive index measurements. While our value for the amplitude ratio A+/A −=0.56±0.02 was consistent with other recent experimental determinations in binary liquid mixtures, it was slightly larger than either theoretical predictions or recent experimental values in liquid‐vapor systems. The correction to scaling amplitude ratio D+/D −=0.5±0.1 was half o...