Glycerol and spent lye clarification - Illinois Institute of Technology

and pure water be observed suocesaively.
Tablea in the appendix give the differences
between the refractive index of water and
aqueous solutions of glycerol of different
concentration. The table of specific gravity
of aqueous solutions is also given in the
appendix.
F. Schulze (Chem. Zeit., 1906, 29, 976,)
has recently made a systematic comparison of
the methods in us© for estimating glycerol; he
gives tables showing the results obtained with
fats, soaps, and various commercial glycerols.
The following are his principle conclusions :-
(1) The permanganate method is considered
unreliable in all cases, whether carried out
by the method of Benedikt and Zisigmondy or by
Herbig or Mangold's modifications.
(2) The diohroraate method gives high results.
Approximate values may be obtained by lowering
the figures obtained by ten percent. This
method is valid only in the absence of phos-
phoric acid.
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