Methods and systems for isochoric measurements using differential scanning calorimetry

A process for measuring a vapor-liquid phase transition of a confined substance in a constant volume system, comprising:

• (a) introducing a substance into a sample cell of a calorimetric block of a differential scanning calorimeter (DSC) at a first initial pressure, the system volume being constant, the sample cell containing an adsorbent;
• (b) maintaining the substance in a liquid phase;
• (c) heating the substance at a heating rate, wherein the heating rate is from about 0.01° C./min to about 0.1° C./min;
• and
• (d) generating a thermogram of a vapor-liquid phase transition of the substance confined inside a pore of the adsorbent.

A process for measuring a vapor-liquid phase transition of a confined substance in a constant volume system, comprising:

• (a) introducing an adsorbent into a sample cell of a calorimetric block of a differential scanning calorimeter, the system volume being constant;
• (b) introducing a substance into the sample cell at a first initial pressure;
• (c) maintaining the substance in a vapor phase or maintaining the substance in a liquid phase;
• (d) cooling the substance at a cooling rate when the process comprises maintaining the substance in a vapor phase, or heating the substance at a heating rate when the process comprises maintaining the substance in a liquid phase, wherein the cooling rate or the heating rate is from about 0.01° C./min to about 0.1° C./min;
• and
• (e) generating a thermogram of a vapor-liquid phase transition of the substance confined inside a pore of the adsorbent.