Following our qualitative observation of decreasing viscosity with
increasing mol percent ChCl, we measured the viscosity of four DESs
prepared with waste glycerol (see Fig. 3). As predicted in the literature,
the viscosity of the mixtures decreased with increasing ChCl [24]. This
decrease in viscosity helps confirm the formation of a DES (not just a
simple mixture of the two components). For the 15 and 25% ChCl
DESs, the viscosity measurements were well within the measurement
error (approximately 5%) of the literature values for DESs prepared
with clean glycerol. However, for the 5 and 35% ChCl DESs, the viscosities
with waste glycerol were, on average, approximately 25% different
than the literature values (while still retaining the trend of decreasing
viscosity with increasing ChCl) [24].