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BAYGUZINA et al.
zyl butyl ether by the intermolecular dehydration of Brunauer–Emmett–Teller (BET) method for a rela-
tive partial pressure of Р/Р0 = 0.2 [19].
benzyl and n-butyl alcohols over a novel heteroge-
neous catalyst based on CuBr2 supported on zeolite
HY with a hierarchical pore structure.
Macropore volume was determined by mercury
porosimetry on a Porosimeter-2000 instrument. Mer-
cury penetration into pores with a radius of 30–
10000 Å was performed at a pressure of 0.1–200 MPa.
EXPERIMENTAL
To determine the valence state of copper in the cat-
alyst composition, electronic diffuse reflectance spec-
tra of samples in the ultraviolet and visible regions
were recorded on a Shimadzu UV-2501 PC spectrom-
eter in a spectral range of 200–900 nm using an IRS-
250A diffuse reflectance attachment. The spectra of
the catalyst samples were recorded in air without pre-
conditioning. Prior to spectra recording, the pow-
dered catalysts were placed in a quartz cell with an
optical path length of 2 mm. The experimentally
determined radiation reflection coefficients (R) were
converted to units of the Kubelka–Munk function
F(R) by the following equation: F(R) = (1 − R)2/2R.
Chromatographic analysis of the products was
conducted on a Shimadzu GC-9A instrument (2 m ×
3 mm column; stationary phase, SE-30 (5%) on
Chromaton N-AW-HMDS; temperature program-
ming, 50–270°С; heating rate, 8°C/min; carrier gas,
helium (47 mL/min)).
Mass spectra were recorded on a Shimadzu
GCMS-QP2010Plus gas chromatograph–mass spec-
trometer system (30 m × 0.25 mm SPB-5 capillary
column; carrier gas, helium, temperature program-
ming, 40–300°C; heating rate, 8°C/min; evaporator
temperature, 280°C; ion source temperature, 200°C;
ionization energy, 70 eV).
Nuclear magnetic resonance (NMR) spectra were
recorded on Bruker Avance-400 spectrometers (400.13
and 100.62 MHz, respectively) in CDCl3.
Materials and Reagents
The precursors were n-butyl alcohol (BunOH,
99%), benzyl alcohol (BnOH, 99%), and CuBr2
(99%), all available from Acros Organics.
Synthesis Procedure
for Supported CuBr2/HY Catalyst System
Zeolite HY with a micro–meso–macroporous
structure was used as a support; the zeolite synthesis is
described in [18]; hereinafter, it is referred to as HY.
Supported CuBr2/HY catalysts were prepared by the
incipient wetness impregnation of a calcined pellet-
ized HY zeolite with a CuBr2 alcoholic solution to syn-
thesize catalysts with a given salt content. After
impregnation, the pellets were dried in a nitrogen
atmosphere at 170°C to remove alcohol and adsorbed
water. Samples with a salt content of 5, 10, and
20 wt % are designated as CuBr2(5%)/HY,
CuBr2(10%)/HY, and CuBr2(20%)/HY, respectively.
Catalytic Testing Procedures
The intermolecular dehydration of benzyl and
butyl alcohols was run in a flow reactor at 140–160°С
and a pressure of 1 atm with a catalyst load of 2 g (frac-
tional composition of 0.1–0.2 mm). The BnOH :
BunOH molar ratio in the feedstock was 1 : 4. The feed
space velocity was 1.0 h−1. Before the reaction, the cat-
alyst was preheated at 170°C in a dry nitrogen stream
(3 mL/min) for 3 h to remove adsorbed moisture.
Reaction products were sampled at intervals of 4 h.
RESULTS AND DISCUSSION
Table 1 shows results of elemental analysis for dried
catalyst samples. It is evident that the CuBr2 content in
the catalyst is close to the calculated value.
Figure 1 shows XRD patterns of the studied sam-
ples. It is evident that the XRD patterns for all the
samples exhibit the principal signals characteristic of a
HY zeolite phase with high phase purity and crystal-
linity. For the sample with a CuBr2 content of 20%,
there is a signal at 45°, which is attributed to the pres-
ence of the CuBr2 phase. The absence of this signal for
the samples with a lower salt content is apparently due
to the high degree of dispersion of the CuBr2 particles.
It should be noted that the introduction of CuBr2 into
Analysis Methods
Copper(II) bromide content in the dried catalyst
samples was determined by X-ray fluorescence spec-
trometry on a Shimadzu EDX 900HS instrument.
X-ray diffraction (XRD) analysis of the uncalcined
samples was conducted on a Bruker D8 Advance dif-
fractometer using CuKα radiation. Scanning was con-
ducted in a 2θ angular range of 3° to 50°–80° with a
step size of 1°/min; the acquisition time was 2 s per
point. The XRD patterns were processed using the the zeolite composition has hardly any effect on the
TOPAS and EVA software programs and the PDF2
database.
phase composition and crystallinity of the zeolite; this
fact suggests that the structure of the selected zeolite is
stable with respect to the introduction of the active
component.
Specific surface area and micro- and mesopore
volumes were determined by low-temperature nitro-
gen adsorption–desorption on a Nova 1200e sorption
Table 2 lists characteristics of the pore structure of
meter. The specific surface area was calculated by the the studied samples. The data show that the HY zeolite
PETROLEUM CHEMISTRY
Vol. 60
No. 8
2020