TECHNOLOGIES FOR PROCESSING OF CRUDE GLYCEROL
1485
The equilibrium conversion of glycerol in this case is
0% at 20–25°С. The major fraction of mineral salts
REFERENCES
8
present in crude glycerol precipitates from the reaction
products. After neutralization of the reaction mixture,
the soaps that are formed from fatty acids dissolved
in crude glycerol precipitate also. Solketal with the
main substance content of no less than 99.5 wt % can
be isolated from the neutralized reaction products by
fractional distillation after separating the precipitate.
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The solketal synthesized from crude glycerol can be
used for producing glycerol of any quality, up to the level
meeting the requirements of food and pharmaceutical
industry. The reversibility of the solketal synthesis
allows its hydrolysis to be performed with virtually
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. Konstantinović, S.S., Danilović, B.R., Ćirić, J.T.,
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00% glycerol yield when the acetone formed in the
. Dmitriev, G.S., Terekhov, A.V., Zanaveskin, L.N.,
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process is distilled off. An acid catalyst is required for
the solketal hydrolysis. Sulfuric acid exhibiting strong
acid properties causes the formation of an appreciable
amount of a by-product, acrolein, whose concentration
in the glycerol obtained can reach 1.5%. WithAmberlyst
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3
5Wet resin used as a catalyst, the relative contribution
of this side reaction can be reduced to a minimum,
and the acrolein content of the glycerol obtained does
not exceed 0.05 wt %. Additional vacuum distillation
of glycerol allows obtaining a high-quality (up to
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9
9.8 wt %) product.
A flowsheet for processing of crude glycerol to obtain
solketal and then pure glycerol via solketal hydrolysis
has been suggested.
1
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ACKNOWLEDGMENTS
1
1. Patent JP 2006290815, Publ. 2006.
The study was performed within the framework of
the government assignment for the Topchiev Institute of
Petrochemical Synthesis, RussianAcademy of Sciences.
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RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 91 No. 9 2018