resulted
in the formation of solids.
Interestingly, the addition of ChCl to waste glycerol from the acidcatalyzed
biodiesel reaction to prepare DESs appears to serve as a purification
technique. Before the addition of ChCl, all waste glycerol samples
were homogeneous, amber colored liquids which would stand
unchanged for days to weeks. The addition of ChCl to these homogeneous
samples engenders a dark upper layer at the surface of the
amber colored solution. 1H NMR analysis shows that the darker layer
is pure biodiesel. Thus, the formation of the DESs forces biodiesel from
the waste glycerol sample. This purification technique may have some
utility in other glycerol refining capacities as well.