METHANOL SYNTHESIS IN A THREE-PHASE SLURRY REACTOR
575
in accordance with the XRD data (Fig. 3), after catal-
ysis, copper is preserved in the zero-valence state and
zinc is present in the form of oxide, it may be assumed
that zinc oxide concentrates on the catalyst surface.
0.3
1288
870
990
c
Thus, this study has revealed that the effective three-
phase synthesis of methanol may be accomplished in
the three-phase slurry reactor in the presence of ultraf-
ine catalyst systems formed in situ in the hydrocarbon
dispersion medium. It has been shown that drop ther-
molysis provides an opportunity to produce nanosized
catalyst suspensions containing components whose
structure and composition are analogous to those of
commercial low-temperature heterogeneous catalysts
of methanol synthesis. These ultrafine catalyst systems
are activated in a more severe regime compared to con-
ventional catalysts. It is found that partial oxidation of
the dispersion medium occurs during the synthesis of
1
570
1730
b
a
0
8
00 1000 1200 1400 1600 1800
cm
Fig. 5. IR spectra of (а) paraffin, (b) Cu–Zn–Al after acti-
vation, and (c) deactivated Cu–Zn–Al sample after catal-
ysis.
after reduction; however, the peaks become narrower. the mentioned ultrafine catalysts from nitrates. This
On the basis of this observation, it may be inferred that
the crystallites of zinc oxide enlarge partially.
circumstance may contribute to additional stabilization
of the nanosized suspension.
The XRD spectra of the sample that lost activity
It has been shown that during catalysis the size of
copper and zinc oxide crystallites grows apparently
owing to the recrystallization of copper, despite the
improved heat exchange in the slurry reactor. The
(
Fig. 4d) after catalysis exhibit narrower reflections
compared with the activated sample (Fig. 4c). This
fact indicates further enlargement of crystallites for all
of the components.
recrystallization of Cu and the reduction of Cu O to
2
0
In Fig. 5, the IR spectra of the initial paraffin are
compared with the spectra of the samples after activa-
tion and catalysis in paraffin. In the IR spectra of the
samples after catalysis, bands corresponding to paraf-
fin with a considerably altered structure predominate.
The band at 730 cm , which characterizes the ordered
linear paraffin chains, is practically absent. This
observation indicates a strong change in the confor-
mation of paraffin units and may be explained by their
arrangement around a nanosized metal-containing
particle to form spherical shells. The spectrum of the
sample after activation exhibits weak bands at 1570
Cu apparently lead to the loss of catalyst activity.
REFERENCES
1
. Methanol production in Russia. http://www.newchemistry.
–1
ru/letter.php?n_id=8471.
2
3
. E. M. Yur’ev and E. V. Popok, Fundam. Res. 8 (3)
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Pet. Chem. 56, 77 (2016).
and 1730 cm corresponding to ionized and acidic
carboxylate groups, respectively. Probably, during the
decomposition of the introduced metals nitrates, the
5. S. N. Khadzhiev, S. A. Sagitov, A. S. Lyadov,
M. V. Kulikova, and A. Yu. Krylova, Pet. Chem. 54,
88 (2014).
–
partial oxidation of paraffin occurs to afford С(О)О
6
. G. N. Bondarenko, M. V. Kulikova, A. Kh. Khaz-
radzhi, Al’, O. S. Dement’eva, M. I. Ivantsov, and
M. V. Chudakova, Pet. Chem. 56, 1128 (2016).
and С(О)ОН terminal groups that are preserved even
after activation. As follows from the intensity of
absorption bands, the amount of these groups does
not exceed 0.1%. Of special note is that the formed
fatty acids and their salts are used for stabilization of
nanosized suspensions [11]. After catalysis, the
7. C. V. Ovesen, B. S. Clausen, J. Schiotz, P. Stoltze,
H. Topsoe, and J. K. Norskov, J. Catal. 168, 133
(
1977).
–
absorption bands due to С(О)О and С(О)ОН groups
are absent; this circumstance probably facilitates the
8. C. Baltes, S. Vukojevic, and F. Schuth, J. Catal. 258,
34 2008.
3
enlargement of catalyst particles.
9. F. Ren, L. Hansheng, D. Wang, and J. Wang, Amer.
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In the spectrum of the sample inactive after catalysis,
–
1
new broad bands appear at 970, 990, and 1288 cm . 10. A. Cybulski, Catal. Rev.–Sci. Eng. 36, 557 (1994).
These bands cannot be assigned to paraffin but may
be attributed to the overtones of long-wave bands of
М–О bonds (200–500 cm ) in metal oxides. Note
that after activation these bands were absent probably
because during catalysis the surface of catalyst parti-
cles transformed into a more oxidized state. Because
1
1. A. Rittermeier, M. K. Schroter, Sh. Miao, X. Zhang,
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Translated by T. Soboleva
PETROLEUM CHEMISTRY Vol. 57 No. 7 2017