ISSN 0965-5441, Petroleum Chemistry, 2019, Vol. 59, No. 5, pp. 504–510. © Pleiades Publishing, Ltd., 2019.
Russian Text © The Author(s), 2019, published in Nanogeterogennyi Kataliz, 2019, Vol. 4, No. 1, pp. 23–29.
Properties of Nanosized Cobalt-Molybdenum Sulfide Catalyst
Formed in situ from Sulfonium Thiosalt
M. I. Knyazevaa, *, D. I. Panyukovaa, and A. L. Maximova, b
aTopchiev Institute of Petrochemical Synthesis, Russian Academy of Sciences, Moscow, 119991 Russia
bFaculty of Chemistry, Moscow State University, Moscow, 119991 Russia
*e-mail: knyazeva@ips.ac.ru
Received December 20, 2018; revised January 10, 2019; accepted January 14, 2019
Abstract—A cobalt-molybdenum-containing sulfonium thiosalt is prepared; when decomposed in situ, it
forms the catalyst active in hydrogenation and hydrodesulfurization. The possibility of catalyst isolation and
reuse in several hydrogenation cycles is shown. It is found that a lower selectivity for naphthalene hydrogena-
tion products in catalyst recycling is associated with decrease in the dispersity of molybdenum sulfide
nanoparticles and reduction in the degree of their promotion by cobalt atoms.
Keywords: nanosized catalyst, hydrogenation, hydrodesulfurization
DOI: 10.1134/S0965544119050049
Oil recycling distillates are characterized by an marily investigated in the process of dibenzothiophene
increased content of polycyclic aromatic, olefin, and hydrodesulfurization. The in situ activation of ammo-
diene hydrocarbons and hard-to-remove sulfur-con- nium thioprecursors for the synthesis of molybdenum
taining cyclic compounds [1]. In view of toughening and tungsten sulfides was first proposed by the authors
environmental regulations and fuel quality standards,1
there is need to remove/decrease the concentration of
polyaromatic and sulfurous compounds in the hydro-
carbon feedstock; this aim may be attained by hydro-
treating. Hydrotreating is a large-scale catalytic pro-
cess [2] involving hydrodesulfurization [3, 4], hydro-
denitrogenation [5, 6], and hydrodearomatization
reactions [7, 8]. For a long time Co(Ni)/Mo(W) sul-
fide catalysts supported on γ-Al2O3 have been basic
hydrotreating catalysts for various kinds of crude oil
feedstock [9]. However, at present, they do not meet
modern world requirements implying the involvement
of heavy hydrocarbon feedstock in processing [10].
This stimulated the design of novel highly efficient
unsupported dispersed catalysts for hydroconversion
of the hydrocarbon feedstock in the slurry regime [11,
12]. Sulfide catalysts may be synthesized both by the
ex situ and in situ decomposition of precursor com-
pounds in the reaction medium. This provides forma-
tion of nanoscale and mesoscale particles and ensures
a high content of sulfur in the final sulfide catalyst [13,
14]. The most common precursors of nanosized sul-
fide catalysts are thiosalts: ammonium thiomolyb-
dates and tungstanates [15, 16] and alkyl thiomolyb-
dates and tungstanates [17, 18]. Their activity was pri-
of [19]. The same research team showed [20] that the
situ formation of WS2 from thiosalts provides a 5-fold
increase in the specific surface area of sulfide com-
pared with that prepared ex situ and thus ensures a
higher catalytic activity. It is known that the introduc-
tion of cobalt or nickel promoting additives in the case
of supported sulfide W/Mo-containing catalysts
affects their activity and selectivity in hydroconversion
reactions [21, 22]. The same tendency is observed for
the in situ formation of catalysts from thiosalts. For
example, the authors of [17] demonstrated that, when
the bimetallic Co–Mo-containing precursor is used
for catalyst formation, the reaction of dibenzothio-
phene hydrodesulfurization occurs via the
direct desulfurization pathway. For trimetallic pro-
moted systems, activity is also influenced by the
method of catalyst synthesis [23, 24]. For example, for
the Ni–Mo–W catalyst formed in situ, the degree of
hydrogenation is higher. This observation is attributed
to the formation of carbide-like admixture phases. No
data are available on the activity of unsupported sul-
fide catalysts formed in situ from thio precursors in the
hydrogenation of aromatic hydrocarbons.
As is known, the presence of nitrogen atoms in the
ammonium precursors hinders formation of the sul-
fide phase and, hence, decreases the number of cata-
lytically active sites. Therefore, the simplest prepara-
tive variant which stipulates replacement of the
ammonium cation with the sulfonium one is pro-
1
The RF Government resolution no. 118 of February 27, 2008,
On Adoption of Technical Regulation On Requirements for
Automobile and Aviation Gasolines, Diesel and Marine Fuels,
Jet Fuel, and Heating Oil.
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