RUTHENIUM- AND PALLADIUM-CONTAINING CATALYSTS BASED
1137
Transmission electron microscopy (TEM) studies insertable glass tube. The calculated amounts of the
were carried out on a LEO912 AB OMEGA micro- catalyst ground into powder, guaiacol, and water and a
scope. TEM images were processed and the average magnetic stirrer anchor were placed in the insertable
particle size was calculated using the program ImageJ. glass tube. The tube was placed in the autoclave, the
The size of resorcinol-formaldehyde nanospheres was autoclave was pressurized, filled with hydrogen to a
determined by dynamic light scattering on a Malvern pressure of 4.0 MPa, held at a temperature of 200°С,
Zetasizer Nano ZS instrument. Sample preparation and stirred at a rate of 1000 rpm for 2 h. When the reac-
was conducted by suspending 100 mg of sample in tion was completed, the autoclave was cooled below
1
0 mL of water. Nitrogen adsorption/desorption iso- room temperature and depressurized. The reaction
therms were measured at T = 77 К using a Gemini VII mixture was diluted with 2 mL of acetone, and the cat-
2
390 surface area analyzer. Before analysis the samples alyst was separated by centrifugation. The sample was
were degassed at a temperature of 120°С for 12 h. The analyzed by gas-liquid chromatography.
specific surface area of the samples was assessed by the
Brunauer–Emmett–Teller (BET) method using the
RESULTS AND DISCUSSION
The nanospherical mesoporous polymer based on
adsorption data obtained in the relative pressure
(
Р/Р ) range of 0.04–0.2. The pore volume and pore
0
size distribution were determined from the adsorption resorcinol and formaldehyde was synthesized by the
branches of the isotherms using the Barrett–Joyner– soft template method at low concentrations of reac-
Halenda (BJH) method. The quantitative analysis of tants. The resulting polymer was studied by TEM,
metals in the catalyst was conducted by inductively dynamic light scattering, and low-temperature nitro-
coupled plasma atomic emission spectroscopy (ICP- gen adsorption.
AES) on an IRIS Interpid II XPL instrument
The TEM microphotographs (Fig. 1) show poly-
(
Thermo Electron Corp., United States) in radial and
mer particles with diameters of 50–380 nm; the aver-
age particle size is 220 ± 10 nm. Mesoporous channels
with an average size of 6 ± 0.5 nm are observed on the
particles. The sizes of nanospheres (average size,
nanosphere size distribution) determined by estimat-
ing parameters of more than 500 particles agree with
the dynamic light scattering data.
axial viewing configurations at a wavelength of
45.5 nm. Substrates and reaction products were ana-
2
lyzed on a Kristallyuks 4000 M chromatograph
equipped with a flame-ionization detector and a Pet-
rocol® DH 50.2 capillary column coated with the
polydimethylsiloxane stationary liquid phase (dimen-
sions, 50 m × 0.25 mm; carrier gas, helium; split ratio,
The characteristics of the synthesized mesoporous
1
2
: 90). Analysis conditions: column temperature,
polymer are as follows: a specific surface area of
35°С; detector temperature, 300°С; and injector
2
2
95 m /g, a pore size of 5.6 nm, and a pore volume of
temperature, 300°С. Chromatograms were recorded
and analyzed on a computer using the program
NetChrom. Conversion was calculated as a change
in the relative surface areas of the substrate and prod-
ucts (%).
3
0
.17 cm /g. The nitrogen low-temperature adsorption
isotherm for the polymer NSMR (Fig. 2) is intermedi-
ate between type II, which is typical of microporous
materials, and type IV corresponding to mesoporous
materials; according to the IUPAC classification, the
hysteresis loop is of type Н-4, which is typical of mes-
oporous carbons and zeolites [14]. The hysteresis loop
is open, which is often observed due to polymer swell-
ing in the presence of condensed nitrogen [15].
The nanospherical mesoporous polymer NSMR
was synthesized as described in [13; however, in this
study a template was annealed at a temperature of
3
60°С to keep the polymer structure. For the synthesis
of the catalyst Ru-NSMR 0.8 g of NSMR, 68 mg of
The NSMR materials were modified via impregna-
RuCl , and 60 mL of water (solvent) were loaded in a
3
tion with the calculated amount of metal salt (RuCl ,
1
00-mL round bottom flask and the resulting mixture
3
Pd(OAc) ) to obtain Pd and Ru catalysts (Pd-NSMR
was stirred for 24 h. The impregnated NSMR polymer
2
was removed from solution by centrifugation and and Ru-NSMR). According to ICP-AES, the metal
placed together with 50 mL of ethanol and 10 mL of content in the catalysts was 0.5 wt % Pd in Pd-NSMR
water in a 100 mL round-bottom flask equipped with and 4.0 wt % Ru in Ru-NSMR. Pd-NSMR and Ru-
a reflux condenser. NaBH (150 mg) was added in
4
NSMR samples were metal nanoparticles with average
sizes of 7.2 and 2.2 nm, respectively, immobilized in
pores of the nanospherical support NSMR (Fig. 3).
Ru nanoparticles occurred both in the form of
agglomerates and as individual particles; the propor-
portions to the reaction mixture, and the mixture was
stirred for other 12 h at room temperature. The
obtained suspension was centrifuged, washed with
water and ethanol, and dried at a temperature of 60°С.
The catalyst Pd-NSMR was synthesized in a simi- tion of agglomerates was no more than 10% of the total
lar manner but Pd(OAc) was used as a source of pal-
ladium and СHCl was used as a solvent.
Catalytic tests were run in a steel thermostated NSMR 2-methoxycyclohexanol is the major product
autoclave equipped with a magnetic stirrer and an of guaiacol hydrogenation (Table 1). The highest
2
amount of Ru nanoparticles.
3
In the presence of catalysts Ru-NSMR and Pd-
PETROLEUM CHEMISTRY Vol. 60 No. 10 2020
Boronoev, M. P.
