1070-4272/03/7607-1182$25.00C 2003 MAIK [Nauka/Interperiodica]
Russian Journal of Applied Chemistry, Vol. 76, No. 7, 2003, pp. 1182!1184. Translated from Zhurnal Prikladnoi Khimii, Vol. 76, No. 7,
2003, pp. 1216!1218.
Original Russian Text Copyright + 2003 by Platonov, Kudrya, Proskuryakov.
Structure of Asphaltene Compounds
Formed by Homogeneous Pyrolysis of 2-Naphthol
V. V. Platonov, A. N. Kudrya, and S. V. Proskuryakov
Leo Tolstoy Tula State Pedagogical University, Tula, Russia
St. Petersburg State Technological Institute, St. Petersburg, Russia
Received April 24, 2002; in final form, April 2003
Abstract-The structure of asphaltene compounds formed by homogeneous pyrolysis of 2-naphthol was
Although asphaltenes of various origins were
studied in numerous works , their nature is not
understood in detail. At the same time, asphaltenes
play an important role in formation of liquid products
of high-temperature coking of coals; they largely
affect the structure and reactivity of coke and also of
pyrocarbon prepared by pyrolysis of individual hydro-
carbons and their mixtures.
To optimize processing of fossil fuels and high-
temperature pyrolysis, it is quite necessary to study
in detail the thermal degradation of the raw materials,
including asphaltenes whose content in tars from [pri-
mary] decomposition of the organic matter of fuels
reaches 30 wt %.
In this work we studied the structure of asphaltene
compounds formed by homogeneous pyrolysis of
2-naphthol (800oC, 4.5 s).
Asphaltenes were isolated as described in . The
molecular structure of asphaltenes was characterized
by IR, UV,
H NMR, and
C NMR spectroscopy,
elemental and quantitative functional analysis, and
We found that the asphaltenes are a complex mix-
ture of relatively high-molecular-weight polyfunction-
al compounds in which the prevailing structural frag-
ments are fused aromatic rings and heterocomponents.
Oxygen is present, in particular, in the forms of five-
membered heterocycles inside fused aromatic struc-
tures [like naphtho(benzo)furans] and of quinoid
groups (mainly 1,4-quinones). Phenolic hydroxyls are
present, but alcoholic hydroxyls are not detected at
all. Methoxy groups are present in small amounts.
Among alkyl substituents in the rings, methyl groups
prevail, but the degree of substitution is low. The
mean size of fused systems is four rings.
To elucidate the structural features of asphaltene
compounds in detail, we separated them into fractions
by extraction with acetone, adsorption liquid chroma-
tography, and preparative thin-layer chromatography
Preparative TLC of asphaltene fractions was per-
formed on standard Silufol plates (20 0 20 cm). The
optimal separation of asphaltene fractions was attained
in the following systems (the volume ratio is given in
parentheses): fraction 1.1.1, hexane3diethyl ether3
acetone (5 : 5 : 1); fraction 1.2, hexane3diethyl ether3
ethyl acetate (10 : 10 : 1); fraction 2.1, heptane3di-
ethyl ether (1 : 1); and fraction 2.2, hexane3diethyl
ether (1 : 1).
The bands were developed under UV light (l 254
and 366 nm). The nonluminescent bands were devel-
oped by treatment with solutions of various agents
and also by chromatography on Silufol UV-254 plates
in which the sorbent contained a luminescent additive,
0.05% sodium fluorescein. In this case, the nonlumin-
escent bands were revealed by quenching of the green
luminescence of sodium fluorescein.
The extracts, close-cut fractions, and even individ-
ual asphaltene compounds were characterized by a set
of physicochemical methods.
We found that fractions 1.1.1 and 1.2 have a mixed
hydroaromatic nature; they contain aromatic rings and
heterocyclic groups. Their spectra exhibit absorption
bands n characteristic of fused aromatic systems
(303033080, 150031600, 145031525 cm
aromatic rings are bonded with hydrogenated groups,