ISSN 1070-4272, Russian Journal of Applied Chemistry, 2014, Vol. 87, No. 9, pp. 1279−1283. © Pleiades Publishing, Ltd., 2014.
Original Russian Text © S.M. Danov, A.L. Esipovich, A.S. Belousov, A.E. Rogozhin, 2014, published in Zhurnal Prikladnoi Khimii, 2014, Vol. 87, No. 9, pp. 1286−1290.
ORGANIC SYNTHESIS AND INDUSTRIAL
Modiﬁ cation of Aluminum Oxide as a Method
for Controlling Its Activity and Stability
in Vapor-Phase Dehydration of Glycerol into Acrolein
S. M. Danov
, A. L. Esipovich
, A. S. Belousov
, and A. E. Rogozhin
Alekseev State Technical University of Nizhni Novgorod,
ul. Gaidara 49, Dzerzhinsk, Nizhni Novgorod oblast, 606026 Russia
Lobachevsky State University of Nizhni Novgorod, pr. Gagarina 23, Nizhni Novgorod, 603950 Russia
Received July 25, 2014
Abstract—It is shown that promotion of γ-Al
with zirconium, cobalt, boron, lanthanum, and cerium oxides
strongly affects its catalytic activity and stability in vapor-phase dehydration of glycerol into acrolein. Modiﬁ cation
of gamma-aluminum oxide with acid oxides impairs the stability and activity of the catalyst. Introduction of
lanthanum and cerium oxides into the structure of γ-Al
leads to a decrease in the number of strong acid centers,
which diminishes the activity of the catalytic system and improves its stability.
Gamma-aluminum oxide is widely used as a gas drier
and absorbent [1, 2], but serves in largest amounts as a
support and component of various catalysts [3–6].
One of the most promising processes in which systems
of this kind can be used is the vapor-phase dehydration
of glycerol into acrolein . This is due to the sharp rise
in the manufacture of biodiesel, which has increased in
recent years only in the EU countries by a factor of 50 and
reached 9 million tons in a year . Biodiesel is produced
from vegetable raw materials by catalytic re-etheriﬁ cation
of fatty acid triglycerides with methanol. This yields
glycerol as a by-product whose mass is about 10% of the
mass of the resulting fuel. As a result, a signiﬁ cant excess
of glycerol has formed in the world market, which cause
a substantial drop of its price.
An effective way to control the catalytic activity of
aluminum oxide systems is by chemical modiﬁ cation via
introduction of various additives. The most widely used
additives are compounds of boron [9, 10], cerium ,
lanthanum , nickel [13, 14], cobalt , silicon ,
etc. The modiﬁ ed aluminum oxide can be produced by
coprecipitation and impregnation methods [17, 18].
In , the possibility of using mixed oxides as
catalysts for dehydration of glycerol was considered. A
high selectivity (~50%) was achieved by using the catalyst
composed of 10 mol % TiO
, produced by the
coprecipitation method. However, the high acidity of the
catalyst caused its fast deactivation, with the conversion
of glycerol decreased by 20% after performing the process
during 10 h.
Mixed nickel, magnesium, and aluminum oxides
produced by the coprecipitation method exhibited a
low activity in the reaction of glycerol dehydration into
acrolein . For example, with NiO–MgO–γ-Al
used, the conversion of glycerol did not exceed 50% after
2 h, and the selectivity of acrolein formation was 11–13%,
depending on the process conditions. In this case, the
selectivity of acetol formation was as high as 80%.
The possibility of using CeO
-based mixed oxides in
dehydration of glycerol was considered in . Among
the catalytic systems considered, the maximum selectivity
of acrolein formation (~40%) after 10 h was observed
when the CeO
sample was used; however,
the fall of the conversion was 50%.