1070-4272/01/7401-0157$25.00C2001 MAIK [Nauka/Interperiodica]
Russian Journal of Applied Chemistry, Vol. 74, No. 1, 2001, pp. 157!161. Translated from Zhurnal Prikladnoi Khimii, Vol. 74, No. 1,
2001, pp. 151!156.
Original Russian Text Copyright + 2001 by Platonov, Proskuryakov, Polovetskaya, Shavyrina, Ryl’tsova.
OF FOSSIL FUEL
Distribution of Varius Forms of Organic Nitrogen
in a Lignite Macromolecule
V. V. Platonov, V. A. Proskuryakov, O. S. Polovetskaya,
O. A. Shavyrina, and S. V. Ryl’tsova
Lev Tolstoi State Pedagogical University, Tula, Russia
St. Petersburg State Technological Institute, St. Petersburg, Russia
Received July 26, 1999
Abstract-The chemical composition of organic bases from tars of stepwise semicoking of lignite was
studied. The features of distribution of organic nitrogen in a coal macromolecule and the most probable
pathways of thermal degradation of the nitrogen-containing fragments were examined.
Up to now, fossil fuel is one of the sources of
diverse nitrogen organic compounds (NOCs). Data on
structural types of organic nitrogen and its distribution
in a coal macromolecule are necessary for determining
the chemical structure of coal and recovering in maxi-
mal yield the NOCs of the given structural-group and
qualitative composition. Nitrogen organic compounds
are valuable raw materials for preparing a wide set of
pesticides, pharmaceuticals, dyes, heat-resistant fibers,
special-purpose rubbers, ion-exchange resins, flotation
agents for rare and rare-earth metals, surfactants, and
vitamins. Recovery of NOCs from coals in high yield
is hampered by the lack of detailed information on the
chemical composition of the semicoking tars, which,
in turn, does not allow scientifically substantiated
selection of the initial brown coals and optimization
of their processing.
The goals of this work were to study in detail the
chemical composition of organic bases from tars of
stepwise semicoking of lignite,
determine the fea-
tures of distribution of organic nitrogen in the lignite
macromolecule, and reveal the most probable path-
ways of thermal degradation of the nitrogen-contain-
Semicoking was performed in a retort so as to min-
imize the pyrolysis of [primary] vapor3gas products
. Therefore, the major components of these prod-
ucts can be fairly reliably assigned to certain native
fragments of the organic matter of lignite (OML).
The tar was collected in three temperature ranges (oC):
(I) <350, (II) 3503450, and (III) 4503500oC, corre-
Lignite from the Near-Moscow fields was studied (Kimovsk
sponding, according to DTA, to the maximal yield of
the tar. The tar yield (wt % based on OML) in stages
I, II, and III was 1.5, 4.9, and 3.4, respectively.
The tars were subjected to total chemical group
analysis . The yield of organic bases in stages I, II,
and III, wt % based on anhydrous tar (wt % based
on OML), was 0.85 (0.013), 1.85 (0.091), and 1.17
The general characterization of the molecular struc-
ture of nitrogen organic compounds was based on data
of IR, UV,
C NMR spectroscopy, cryoscopy,
elemental and quantitative functional analysis, and
capillary gas3liquid chromatography (CGLC) .
The structural-group composition of organic bases
from tars of stepwise semicoking of Near-Moscow
lignite, calculated from the CGLC data, is listed in the
table. It is seen that the organic bases recovered in
different temperature ranges of OML degradation sig-
nificantly differ in the structural-group composition.
For example, the tars recovered in the temperature
range 3503 450oC have a high content of picolines,
lutidines, ethyl-, n-propyl-, isopropyl-, n-butyl-, and
isobutylpyridines, and aliphatic and aromatic amines.
The content of pyridine, quinoline, isoquinolines,
benzoquinolines, benzoisoquinolines, indoles, carba-
zoles, hydrogenated quinolines and benzopyrroles, and
polycyclic NOCs is the highest in the tars recovered
in the range 4503550oC.
The distribution of NOCs in the coal macromole-
cule can be estimated more descriptively from the
yield of separate groups of NOCs (see table). It is
seen that the tar recovered in the second stage of