HYDRODEOXYGENATION OF PALMITIC AND STEARIC ACIDS
1327
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matography methods using a flame ionization detec-
tor (GC-FID) and a mass spectrometric detector
(GC-MS). The catalyst was washed with n-hexane
and ethanol and dried in a fume hood. After that, the
catalyst was analyzed by X-ray powder diffraction
(XRD) and X-ray photoelectron spectroscopy (XPS).
* Ni2P
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Instruments and methods. The qualitative analysis
of liquid products was carried out on a Finnigan MAT
95 XL gas-liquid chromatograph (Thermo Scientific)
equipped with a mass spectrometric detector and a
Varian VF-5MS capillary column (30 m × 0.25 mm ×
0.25 μm) using helium as a carrier gas. The quantita-
tive analysis of liquid products was carried out on a
Kristallyuks 4000M gas-liquid chromatograph (Meta-
Chrom) equipped with a flame ionization detector
and an SPB-1 capillary column (Superlco, 30 m ×
0.25 mm × 0.25 μm) using helium as a carrier gas.
Before quantitative analysis, samples were prepared
according to the known procedure [10]. The sample
solution (1 mL) was placed in a vial, and methanol
(1 mL) was added. Acetyl chloride (50 μL) was care-
fully added dropwise to the mixture. The resulting
mixture was held under stirring for 2 h at a temperature
of 70°C until methyl esters of fatty acids formed. The
mixture was cooled to room temperature, and benzene
(2 mL) was added. The pH of the reaction mixture was
neutralized with an aqueous K2CO3 solution. Then the
resulting mixture was shaken and centrifuged for 5 min
(5000 rpm). The nonpolar phase was analyzed.
* CoP
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Co(PO3)2
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30 40 50 60 70 80 90 100
10 20
2θ, deg
Fig. 1. X-ray powder diffraction patterns of nickel and
cobalt phosphides formed in situ from oil-soluble precur-
sors in the reaction medium. Phases identified: Ni P
2
(PDF#65-9706), CoP (PDF#29-0497), and Co(PO )
3 2
(PDF#27-1120).
phosphides in situ in the reaction medium and to
examine their catalytic activity.
EXPERIMENTAL
Materials. The catalysts were prepared using
cobalt(II) 2-ethyl hexanoate (Aldrich, 65 wt % solu-
tion in C10–C13 iso-alkanes), nickel(II) 2-ethyl hexa-
noate (Aldrich, 78 wt % solution in 2-ethylhexanoic
acid), and trioctylphosphine (Acros, 90%). Stearic
acid (Komponent reaktiv, Russia; high-purity grade)
and palmitic acid (Reakhim, Russia; high-purity
grade) were used as substrates, and benzene (Ekros,
Russia; reagent grade) was used as a solvent. H2 (Air
Liquide, ≥98%) and Ar (Air Liquide, ≥98%)
gases were used. In addition, methanol (Reakhim,
reagent grade), acetyl chloride (Sigma-Aldrich,
≥99%), n-heptane (Komponent reaktiv, reagent
grade), ethanol (Reakhim, reagent grade), KMnO4
(Komponent reaktiv, high-purity grade), and K2CO3
The XRD analysis of the catalysts was carried out
using a Rotaflex RU-200 (Rigaku) diffractometer
(CuKα radiation) in the 2θ angle range of 5°–100°
with a D/Max-RC (Rigaku) goniometer at a rotation
speed of 1° 2θ/min with a step of 0.04°. The average
crystallite size was estimated from the widths of corre-
sponding reflections using the Scherrer formula
(Fig. 1).
The XPS analysis of the catalysts was carried out on
an ESCALAB MK2 electron spectrometer (Vacuum
Generators Ltd.). The surface of the samples was
(Komponent reaktiv, high-purity grade) were used. All investigated without heating and ion-beam treatment;
solvents were purified by standard procedures.
the position of the lines of elements was normalized to
the position of the carbon line C1s due to hydrocarbon
surface contamination. The survey spectrum was
obtained at an analyzer pass band of 50 eV with a scan
step of 0.25 eV; partial element spectra were obtained
at a pass band of 20 eV with a scan step of 0.2 eV.
Catalyst synthesis and catalytic activity runs. The
calculated amount of precursors (0.0436 mmol of
cobalt(II) or nickel(II) 2-ethyl hexanoate and
0.0872 mmol of trioctylphosphine, respectively), sub-
strate (0.218 mmol of stearic or palmitic acid), solvent
(3 g of benzene), and a magnetic stirrer were placed in
a 45-cm3 stainless steel autoclave. The autoclave was
pressurized, filled with hydrogen to a pressure of
5 MPa, and placed in an oven. The reaction was car-
ried out under vigorous stirring at 350°C for 3 and 6 h.
RESULTS AND DISCUSSION
In the nickel phosphide sample, the crystalline
phase of the phosphide of composition Ni2P
Temperature was controlled using a thermocouple. (PDF#65-9706) was identified; the average crystallite
Upon completion of the reaction, the autoclave was size was 50 nm. Two crystalline phases were identified
cooled and the gas was passed through a KMnO4 solu- in the cobalt phosphide sample: the phosphide phase
tion. Afterwards, the autoclave was depressurized. The
reaction products were separated from the resulting
catalyst via centrifugation and analyzed by gas chro- average crystallite size of the phases was 52 and 23 nm,
of composition CoP (PDF#29-0497) and the cobalt
metaphosphate phase Co(PO3)2 (PDF#27-1120). The
PETROLEUM CHEMISTRY Vol. 59 No. 12 2019