In a previous study, a series of density measurements were made on
DESs prepared with 5–33mol% ChCl in fresh glycerol [24]. All DESs prepared
in this study were less dense than pure glycerol (d=1.26 g/mL at
20 °C), with densities gradually decreasing from approximately
1.24 g/mL for 5% ChCl to 1.18 g/mL for 33% ChCl. Fig. 2 shows the results
of density measurements made on DESs in this same composition range
prepared with waste glycerol. The data is striking similar to the density
measurements made using pure glycerol. Froma visual interpretation of
the previous literature report [24] using pure glycerol as the DES HBD,
we estimate that the densities of DESs prepared with waste glycerol
are less than 1% different than the densities of DESs prepared with
pure glycerol.