What determines the drying temperature?

The determination of drying temperature is formulated based on the type of solvent, as various solvent components have different melting points. For example, zinc chloride has a melting point of 283°C and a boiling point of 732°C, whereas ammonium chloride begins to sublime at 350°C. Thus, when zinc chloride is used as the solvent, the drying temperature can be higher than when ammonium chloride is used. Typically, the drying temperature for zinc chloride is set at 200–250°C, while for ammonium chloride, it is only around 120°C. Strictly speaking, the upper limit of the drying temperature is determined by the melting point of the solvent component, and the lower limit is determined by the temperature at which the crystal water in the solvent component can be completely removed.