3. Results and discussion
The results of l-Gn solubility in water and mixed solvents are listed in Table 1.
Fig. 4 gives the plot of the solubility of l-Gn in these solvents at a temperature range of about 278–313 K. In all of the tables and figures, R, which represents the solvent molar ratio of the solvent mixture,
can be calculated as follows:
where Ni represents the other solvents except for water,
such as ethanol and acetone.
The solubilities are a function of temperature,
increasing with an increase in temperature.
In the mixed solvent systems,
the solubility would increase with the increasing of R,
which indicates that pure water has a high dissolving power.
Among the two different mixed solvent systems,
only if it has the same solvent molar ratio (R),
the molar fraction solubility will decrease in the same degree.