Abstract The thermodynamic properties and phase behaviour of 1,3-diisopropylnaphthalene were studied for the first time using static vapour pressure measurements, Tian-Calvet calorimetry, and differential scanning calorimetry (DSC). Polymorphic behaviour of the compound was detected and studied in detail by combination of DSC and variable-temperature X-ray powder diffraction. The crystal structure of the disordered metastable phase was obtained using a single-crystal X-ray diffraction for the first time. The experimental study was supplemented by calculating thermodynamic properties in the ideal-gas state using a combination of statistical thermodynamics and quantum-chemical calculations. Recommended vapour pressure equation was derived by simultaneous treatment of vapour pressures, experimental heat capacities of the condensed phases, calculated ideal-gas heat capacities, and temperature and enthalpy of fusion, assuring their mutual thermodynamic consistency.

中文翻译：

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1,3-二异丙基萘的热力学和晶体学联合研究

摘要 采用静态蒸气压测量、Tian-Calvet 量热法和差示扫描量热法 (DSC) 首次研究了 1,3-二异丙基萘的热力学性质和相行为。通过DSC和变温X射线粉末衍射相结合，对该化合物的多晶型行为进行了详细的检测和研究。首次使用单晶X射线衍射获得了无序亚稳相的晶体结构。通过结合使用统计热力学和量子化学计算来计算理想气体状态下的热力学特性，对实验研究进行了补充。推荐的蒸气压方程是通过同时处理蒸气压、凝聚相的实验热容、