Measurements of phase equilibrium temperature and dissociation heat of tetrabutylphosphonium glutarate ionic semiclathrate hydrate

•The highest equilibrium temperature was experimentally determined to be 287.4 K.•The largest dissociation heat was 193.3 ± 1.6 kJ/kg.•This hydrate had suitable thermophysical properties for thermal storage media. Thermophysical properties such as phase equilibrium temperature and dissociation heat are important to determine the performance of phase change materials targeting thermal energy storage. The phase equilibrium temperature and dissociation heat of tetrabutylphosphoniumglutarate ionic semiclathrate hydrate were measured in this study. The highest phase equilibrium temperature of tetrabutylphosphoniumglutarate hydrate was experimentally determined 287.4 K at the mass fraction 0.347 and 0.357. The largest dissociation heat was 193.3 ± 1.6 kJ/kg at the mass fraction 0.357. The measurement results in this work show that the dissociation heat can be utilized in the suitable temperature range targeting general air conditioning and data center.