ISSN 1070-4272, Russian Journal of Applied Chemistry, 2007, Vol. 80, No. 5, pp. 846 !850. + Pleiades Publishing, Ltd., 2007.
Original Russian Text + S.A. Semenova, Yu.F. Patrakov, 2007, published in Zhurnal Prikladnoi Khimii, 2007, Vol. 80, No. 5, pp. 871!875.
OF FOSSIL FUEL
Effect of Ozonation on the Composition
of Crude Coal-Tar Benzene
S. A. Semenova and Yu. F. Patrakov
Institute of Coal and Coal-Tar Chemistry, Siberian Division, Russian Academy of Science, Kemerovo, Russia
Received July 3, 2006; in final form, January 26, 2007
Abstract-The effect of ozonation on the composition of crude benzene produced by the coal-tar chemical
industry was studied.
One of the most urgent problems of coal-tar chemi-
cal industry is improvement of crude benzene quality.
The main impurities deteriorating characteristics of
crude benzene are sulfur-containing, unsaturated, and
saturated hydrocarbons. At present, among procedures
of benzene purification are conventional sulfuric acid
treatment and also fairly expensive catalytic hydrofin-
ing . The latter combines in one process hydro-
genolysis of sulfur-contaning compounds and hydro-
genation of unsaturated hydrocarbons, which allows
production of the pure product, an important raw
material for synthesis of organic compounds .
Difficulties in utilization of wastes formed in sul-
furic acid purification and high capital and operation
costs of hydrofining processing  require develop-
ment of simple and environmentally safe procedures
of purification of crude benzene.
Along with conventional procedures, oxidation
(e.g., with hydrogen peroxide) , ultrasonic treat-
ment , and biotechnologies  are also used for
purification of oil fractions for which the main detri-
mental impurities are unsaturated and sulfur-contain-
Ozonation [7, 8] is suggested as one of oxidation
procedures of purification of diesel fractions. The fea-
ture of ozone is its selective electrophilic addition to
both sulfur-containing and unsaturated compounds
and polycyclic arenes . Unique chemical activity of
ozone allows the reactions to be efficiently performed
at moderate temperatures without catalysts.
Considering similar composition of undesirable
target products of oil refining and coal-tar chemical
industries, ozonation can be one of the feasible proce-
dures of purification of crude coal-tar benzene. In this
connection, our study was aimed to determine how
ozonolysis affects the composition of crude coal-tar
Crude benzene produced by coal-tar shop at the
Novokuznetsk Metallurgic Plant was used as a subject
of the study. The characteristics of the initial product
are presented in Table 1.
Ozonation was performed at 25oC and atmospheric
pressure in a bubbling-type reactor with uninterrupted
feeding of ozone3oxygen mixture (1.5 vol % ozone).
After the process completion, tar products accumu-
lated at the reactor walls and dissolved in benzene
were extracted with 5% KOH. Then, the product
purified to remove tar was treated with 50% H
Table 1. Characteristics of crude benzene
Index ³ Characteristic
External appearance ³Transparent yellow-orange
³liquid without suspended
Density, g cm
Temperature, at which 97% ³ Not higher than 140
of the product is distilled, oC³
Content, wt %: ³
benzene ³ 32.3
toluene ³ 37.1
xylene ³ 13.5
carbon disulfide ³ 0.24
Acidity, mg g
Bromine number, % ³ 5.66