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OXIDATION OF ANGREN BROWN COAL BASED ON A NITRATING
MIXTURE FORMED IN THE PROCESS OF SYNTHESIS OF 2-METHYL-
3(H)-6-NITROQUINAZOLIN-4-ONE
Ziyadullaev Mirjalol E.
Ganiev Pirnazar Kh.
Associate Professor of the Department of Chemistry Chirchik State Pedagogical
University, Doctor of Philosophy in Chemical Sciences (PhD)
е–mail ziyadullayev.91@mail.ru
https://doi.org/10.5281/zenodo.12770461
Annotation.
In this article, nitration reactions of 2-methyl-3(H)-quinazolin-
4-one using nitrating mixture (HNO
3
+H
2
SO
4
) were carried out. As a result, the
mobile hydrogen atom located in the sixth position of the benzene ring in 2-
methyl-3(H)-quinazolin-4-ones is exchanged for the -NO
2
group, resulting in the
corresponding 2-methyl-3(H)-6-nitroquinazolin-4-one as a result of
electrophilic coupling reactions. synthesized. In the process of obtaining the
synthesized product, a large amount of nitrating mixture waste is generated.
This mixture was applied to the oxidation process of Angren mine lignite.
Oxidation process in nitric acid concentration from 5 to 15%, weight ratio of
coal (organic part); When studying HNO
3
:H
2
SO
4
= 1:0.2:0.4 to 1:1:2, it was
shown that it is possible to increase the amount of humic acids in coal from
3.96% to 55.17%.
Key words:
heterocyclic compound, 2-methyl-3(H)-quinazolin-4-one,
nitration, brown coal, oxidized coal, humic acid, fulvic acids
Introduction.
The analysis of the scientific articles published today
worldwide shows that conducting scientific and practical research on the basis
of synthetic heterocyclic compounds containing N, S, O heteroatoms is rapidly
developing. Among such compounds, we can include the quinazolin-4-one
compound, which can be isolated not only from the composition of plants, but
also synthesized by various methods.
The purpose of this research work is the conditions for increasing humic
acids in coal in the presence of the nitrifying mixture formed during the
synthesis of 2-methyl-6-nitro-3(H)-quinazolin-4-one in high yields.
Literature analysis. In the course of our research, in the course of the
analysis of literature sources, researches are being carried out in leading
scientific centers of the world on obtaining new derivatives of bicyclic
quinazolin-4-ones using modern organic synthesis methods, determining their
biological activity and creating drugs with high pharmacological activity and less
toxicological harm. This is due to the presence of bicyclic quinazolin-4-one and
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157
their derivatives with high biological activity and important organic compounds
with analgesic, anti-inflammatory and anti-cancer activity in medicine. In
addition, it can be explained by the fact that it is used in agriculture as a
fungicide, pesticide, insecticide, plant growth stimulator, in the chemical
industry as a raw material for the synthesis of various polymers and artificial
fibers, and as raw materials for obtaining corrosive agents. [1-2]. In our previous
studies, information on the optimal conditions and technology for the synthesis
of 3(H)-quinazolin-4-one, which can be used as an anthelmintic agent in animal
husbandry, is given [3]. In this research work, favorable conditions for the
synthesis of 2-methyl-3(H)-6-nitroquinazolin-4-one, which is an important
intermediate and exhibits high biological activity, are presented. Continuing the
research, in the synthesis of 2-methyl-3(H)-6-nitroquinazolin-4-one, 2-methyl-
3(H)-quinazolin-4-one was synthesized in the presence of a nitrating mixture.
The formation and purity of the synthesized compound was determined by the
TLC method on Silufol UV-254 paper and recrystallized in ethyl alcohol. As a
result, 3(H)-2-methyl-6-nitroquinazolin-4-one was synthesized with 87.4%
yield. The course of the reaction equation and mechanism was proposed as
follows (Figure 1).
Figure 1. Nitration reaction of 2-methyl-3(H)-quinazolin-4-one
The use of the above oxidizers to increase the yield of humic acids from
brown coal creates additional technological difficulties in the application of
inorganic and organic acids. This requires a large amount of water and a lot of
time, as well as additional equipment in the process of washing coal.
It is known from the literature that oxidation of lignite with nitric acid in
the presence of acetic acid [4]. Accordingly, the coal was first treated in a
mechanical lime with acetic acid in a coal:acetic acid ratio of 1:0.05 to 1:0.2 for
30 minutes, oxidation from 10 to 30% was carried out in nitric acid
concentration up to Temperature 40 °C, duration 120 minutes and weight ratio
coal:HNO
3
= 1:2. After oxidation under optimal conditions, the GC content
increased to 66.1%
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The results of the study of oxidation processes of lignite obtained from the
Angren mine with a mixture of nitric and sulfuric acids depending on various
parameters are presented. The optimal process mode was found for the
maximum yield of humic acids and minimum loss of nitrogen oxides. When coal
was oxidized with a mixture of acids, the yield of humic acids increased
significantly and reached 61.62%. In this work, we decided to test the oxidation
process in the presence of a nitrifying mixture against Angren lignite.
Analyzes and results. In the experiments, we obtained 36% sulfate and 24%
nitric acid liquid in the reaction mixture, which is formed in large quantities
when using a nitration mixture in the process of obtaining 2-methyl-3(H)-6-
nitroquinazolin-4-one. We used a ground sample of coal from the Angren mine,
which was air-dried and ball-milled to a size of 0.25 mm to have the following
composition. Humidity 15.26%; ash 13.06%; organic matter 71.68%; For
organic mass, humic acid (GC) is 3.96 and fulvic acids is 0.41. Oxidation process
in nitric acid concentration from 5 to 15%, weight ratio of coal (organic part); It
was found that HNO
3
:H
2
SO
4
= 1:0.2:0.4 to 1:1:2. The experiments were carried
out under the following conditions: first, the coal was treated with a ratio of
mechanically crushed coal (organic part): HNO
3
was added to the mass tube
reactor for mixing from 1:0.2:0.4, where the nitrifying mixture solution was pre
poured and processed for 2 hours. During the oxidation of coal with a nitrating
mixture, the temperature of the reaction mass increased to 30-70 °C, depending
on the speed and concentration of the nitrating mixture. In all experiments, at
the end of the process, the reaction mass was air-dried and its ash content,
moisture content, organic matter, humic and fulvic acid yield were determined.
After extraction of alkali-soluble organic matter from oxidized coal, insoluble
residual carbon remains. It is washed with distilled water, then dried to constant
weight and the amount of insoluble organic matter is determined. The difference
between the amount of alkali-soluble organic matter, humic acids, and insoluble
organic matter gives us the composition of fulvic acids in oxidized coal.
Table 1
Oxidized coal products depend on the concentration of the nitrating
mixture (40
o
C, 120 minutes)
Coal:
HNO
3
:H
2
SO
4
Oxidized
product yield,
Components identified in relation to the
organic part of oxidized coal, %
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mass ratio
%
Organic
substances that
dissolve in an
alkaline
environment
-
The concentration of HNO
3
in the nitrating mixture is 5%
1 : 0,2 : 0,4
102,63
24,12
22,89
1,
23
75,8
8
1 : 0,4 : 0,8
104,46
30,49
28,98
1,
51
69,5
1
1 : 0,6 : 1,2
106,31
41,37
39,32
2,
05
58,6
3
1 : 0,8 : 1,6
106,69
42,09
39,95
2,
14
57,9
1
1 : 1 : 2
107,01
44,41
42,19
2,
22
55,5
9
The concentration of HNO
3
in the nitrating mixture is 10 %
1 : 0,2 : 0,4
103,49
27,58
24,35
1,
43
72,4
2
1 : 0,4 : 0,8
105,01
36,47
36,47
1,
91
64,2
3
1 : 0,6 : 1,2
107,35
48,11
45,65
2,
46
51,8
9
1 : 0,8 : 1,6
108,01
52,34
49,75
2,
59
47,6
6
1 : 1 : 2
108,41
53,61
50,99
2,
62
46,3
9
The concentration of HNO
3
in the nitrating mixture is 15 %
1 : 0,2 : 0,4
104,22
33,62
31,94
1,
68
66,3
8
1 : 0,4 : 0,8
106,49
42,47
40,15
2,
32
57,5
3
1 : 0,6 : 1,2
107,25
54,32
51,24
3,
08
45,6
8
1 : 0,8 : 1,6
110,01
57,76
54,51
3,
25
42,2
4
1 : 1 : 2
110,41
58,51
55,19
3,
32
41,4
9
Conclusion.
The following can be concluded from the above studies. Based
on the conducted research, 36% sulfate and 24% nitric acid liquid was taken
into the nitration reaction mixture formed during the synthesis of 2-methyl-
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3(H)-6-nitroquinazolin-4-one compound. Oxidized coal is 5% HNO
3
, and the
organic mass ratio of coal is HNO
3
:H
2
SO
4
= 1:0.6:1.2. coal obtained using
Foydalanilgan adabiyotlar:
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Aisha Youssif Hassan Helali, Marwa Taha Mostafa Sarg, Makarem
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