Optimization of Synthesis of 2,4-Dinitrophenylhydrazones under Carbon Dioxide Pressure

Article abstract of DOI:10.1023/A:1025774817579

Catalytic synthesis of 2,4-dinitrophenylhydrazones formed in the aqueous reaction mixture of aliphatic and aromatic carbonyl derivatives with 2,4-dinitrophenylhydrazine in the presence of carbonic acid protons under pressure of the CO₂-H_2<

Full text of DOI:10.1023/A:1025774817579

Russian Journal of Applied Chemistry, Vol. 76, No. 4, 2003, pp. 566 568. Translated from Zhurnal Prikladnoi Khimii, Vol. 76, No. 4, 2003,
pp. 586 588.
Original Russian Text Copyright
2003 by Eremeev.
CATALYSIS
Optimization of Synthesis of 2,4-Dinitrophenylhydrazones
under Carbon Dioxide Pressure
A. P. Eremeev
Pod emtransmash Open Joint-Stock Company, St. Petersburg, Russia
Received July 3, 2002; in final form, January 2003
Abstract Catalytic synthesis of 2,4-dinitrophenylhydrazones formed in the aqueous reaction mixture of
aliphatic and aromatic carbonyl derivatives with 2,4-dinitrophenylhydrazine in the presence of carbonic acid
protons under pressure of the CO H O a steam gas mixture was studied for the example of synthesis of
2
2
p-quinone mono-2,4-dinitrophenylhydrazone.
Hydrazones are brightly colored (yellow to red)
chemical products insoluble in water and soluble in
polar organic solvents. Also, hydrazones are thermally
stable up to their melting points and resistant to direct
solar rays and ultraviolet radiation, acids, and oxygen,
and act as microbiocides. All this makes hydrazones
valuable for various chemical, chemical-engineering,
medical, and hygienic applications. When introduced
into protective organic-phase or water-dispersible
paint-and-varnish and impregnating materials, hydra-
zones act as biocides and anticorrosives for wood
and metals.
476 85] made of 12Cr18Ni10Ti steel (filling factor
0.7, working pressure up to 100 MPa, temperature
up to 300 C) equipped with an impeller-type stirrer
(3000 rpm). We used carbon dioxide from cylinders
and the following chemicals: 2,4-dinitrophenylhy-
drazine DNPH (pure grade, TU 6-09-2894 72) and
p-benzoquinone (PBQ, pure grade, TU 6-09-156 76)
in a 1 : 1 molar ratio and also other carbonyl deriv-
atives (RHCO or RR CO with R or R = Alk or Ar).
The condensation of DNPH with PBQ to form
,4-dinitrophenylhydrazone (DNPHN) was studied
2
using the design matrix of full-factorial experiment
Previously, 2,4-dinitrophenylhydrazones have been
synthesized in the presence of protons of a strong in-
organic acid [1]. A drawback of this process is the
need to treat ready-for-use products with an alkali so-
lution to neutralize the residual acid and to additional-
ly wash them with water to completely remove the
forming salts, which leads to a loss of up to 10% of
the target product.
3
(
FFE-2 ) [2] with varied physical factors: X for
1
the carbon dioxide pressure, MPa (lower level 0.5,
upper level 2.5); X for the reaction time, h (0.5, 3.5);
2
and X for the reaction mass temperature, C (50,
3
8
0). After isolation from the reaction mass, DNPH
was dried at 105 C and weighed, whereupon the yield
(% of the theoretical value) was estimated.
The regression equation with the coefficients cal-
In this study, we suggested to catalyze the process
of interest with carbonic acid formed under carbon
dioxide pressure in an aqueous pulp of the reaction
culated by the Yates method [2] adequately describes
3
the experimental responses for FFE-2 (Yi
Yi =
2
mass. We expected that the product to be isolated from Yˆ 1.2 at p = 0.95, f = 2, s = 0.5):
i
the reactor after the condensation of 2,4-dinitrophenyl-
ˆ
Y = 44.9 + 25.3X + 4.9X + 14.9X + 8.5X X . (1)
i 1 2 3 1 3
hydrazone with a carbonyl derivative is complete and
the carbon dioxide pressure is relieved will not re-
quire additional treatment to remove acid, since car-
bonic acid decomposes and carbon dioxide volatilizes
upon completion of the process.
In Eq. (1), the pair interaction effect X X proved
1
3
to be significant, in agreement with the local optimum
of the DNPH PBQ condensation, which is determined
primarily by the concentration of protons and temper-
ature X , and to a lesser extent by the reaction time X .
EXPERIMENTAL
3
2
This corresponds to the reaction mechanism analogous
to that describing the influence of strong acid protons
In our experiments, we used an RTsG-1.6-10-1k-01
.6-l autoclave [TU (Technical Specifications) 26-01-
*
1
[
1, 3] in accordance with the reactions
*
Manufactured by the Staraya Russa Chemical Machine Build-
ing Plant.
RR CO + H+ RR (OH)C+,
(2)
1
070-4272/03/7604-0566 $25.00 2003 MAIK Nauka/Interperiodica

OPTIMIZATION OF SYNTHESIS OF 2,4-DINITROPHENYLHYDRAZONES
Ph(NO ) NHNH + RR (OH)C+
567
2
2
2
+
[
Ph(NO ) NHNH C(OH)RR ] ,
(3)
2
2
2
[
Ph(NO )NHNH C(OH)RR ]
2 2
RR C=NNHPh(NO ) + H+ + H O.
(4)
2
2
The significance of the time factor X is determined
2
by the fact that the reactions are diffusion-controlled
and occur at the DNPH DNPHN PBQ water inter-
face in the pulp of the reaction mass, which is sat-
urated with protons, after the necessary degree of hy-
drolysis of carbon dioxide by the reaction
CO2 + H O
H+ + HCO3
2H+ + CO2 (5)
3
2
3
D diagram of the response surface for X X pair interac-
1 3
is attained under the optimal conditions as determined
ˆ
ˆ
ˆ
i
tion. b = Y
Y
= 45 14 = 31. Y = 12, 32, 80.
0
0
min
by the X and X factors.
1
3
The process becomes predominantly kinetically
controlled [reactions (2) (4)] under conditions of vig-
orous stirring, which continuously renew the DNPH
solid particle surface, thereby making it accessible to
an attack by protonated molecules of the carbonyl der-
ivative dissolved in water. Thus, DNPHN (a loose
product formed on the DNPH particle surface) is re-
moved from the reaction zone owing to constant abra-
sive collisions of the DNPH particles getting over-
grown with a DNPHN layer.
6
8%, i.e., the product yield increases by 68% (in pro-
portion to the doubled reaction time). This suggests
the rates of reactions (2) (4) are invariable for a given
chemical system under the chosen synthesis condi-
tions.
(
3) When the X factor changes from the lower
3
+
(X3 = 0.5 h) to upper (X3 = 1 h) level at fixed
lower level (X = 5 MPa) of the X factor, the re-
1
1
sponse changes by Yˆ = Yˆ Yˆ = 0 12 =
2
1
3
The behavior of the response surface was visual-
ized as the geometric image of the pair interaction
12%, i.e., the product yield increases by 12% only,
owing to a low concentration of protons under de-
creased carbon dioxide pressure and to insufficient
shift of equilibrium (5) to the right.
[4, 5], using the regression equation
ˆ
Y = 45 + 25X + 15X3 + 9X X ,
(6)
i
1
1 3
(
4) When the X factor changes from the lower
3
+
(X3 = 0.5 h) to upper (X3 = 1 h) level at fixed
incorporating significant effects of factors entering
+
1
higher level (X = 20 MPa) of the X factor, the re-
into the X X pair interaction.
1
1
3
sponse changes by Yˆ = Yˆ Yˆ = 80 32 =
4
2
4
The 3D diagram of the response surface of the
4
8%, i.e., the product yield increases by 48%, which
X X pair interaction effect presented in the figure
1
3
is virtually proportional to the reaction time doubled
for chemical reactions (2) (4).
suggests the following.
(
1) When the X factor changes from the lower
1
+
Thus, the interaction of the upper levels of factors
(
X1 = 5 MPa) to upper (X1 = 20 MPa) level at
fixed lower level (X3 = 0.5 h) of the X factor,
X X ensures the optimal influence of these factors
1
3
3
on the product synthesis. This can be accounted for
by a strong shift to the right of the equilibrium in re-
action (2), owing both to an increase in the carbon
dioxide pressure and, hence, in the proton concentra-
tion [reaction (5)] and to rise in temperature, which
favors reactions (3) and (4). This stabilizes the shift
of the equilibria of reactions (2), (3), and (5) at a level
at which the main reaction (4) proceeds in the optimal
regime with high yield of p-quinonemono-2,4-dinitro-
the response changes by Yˆ = Yˆ Yˆ = 32%,
1
1
2
i.e., the product yield grows by 32% when the carbon
dioxide pressure is raised, owing to an increase in
the concentration of protons in the reaction mass via
reaction (5).
(2) When the X factor changes from the lower
1
+
1
(
X1 = 5 MPa) to upper (X = 20 MPa) level at
fixed higher level (X3 = 1 h) of the X factor, the
+
3
response changes by Yˆ = Yˆ Yˆ4 = 12 80 = phenylhydrazone (99.95%).
3
3
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 76 No. 4 2003

5
68
EREMEEV
The experimental results for DNPH PBQ conden-
confirms that the proton catalysis mechanism of con-
densation of 2,4-dinitrophenylhydrazine with p-ben-
zoquinone is similar to that revealed previously for
strong inorganic and organic acids.
sation under the optimal conditions we found were
extended to some other commercial aliphatic and ar-
omatic carbonyl derivatives. The yields of the cor-
responding 2,4-dinitrophenylhydrazones (% of the
theoretical value) were as follows: anisaldehyde 99.7,
acetone 99.2, benzaldehyde 99.5, isobutyraldehyde
(4) The condensation reaction studied is suitable
for synthesizing 2,4-dinitrophenylhydrazones from
aliphatic and aromatic carbonyl derivatives in high
yield (99.3 99.7%).
9
9
9.6, methyl ethyl ketone 99.2, m-nitrobenzaldehyde
9.4, salicylicaldehyde 99.3, and cyclohexanone 99.5.
REFERENCES
CONCLUSIONS
1
2
. Eremeev, A.P., Belyaeva, E.M., and Golounin, A.V.,
(
1) A full-factorial experiment on condensation of
Zavod. Lab., 1986, vol. 52, no. 10, pp. 61 62.
2
,4-dinitrophenylhydrazine with p-benzoquinone to
. Hicks, Ch.R., Fundamental Concepts in the Design of
Experiments, New York: Holt, Rinehart, and Winston,
1973.
p-quinone mono-2,4-dinitrophenylhydrazone suggests
that synthesis of hydrazones can be catalyzed by pro-
tons of carbonic acid formed in the aqueous pulp of
the reaction mass via hydrolysis of dissolved carbon
dioxide under a pressure of the CO H O steam gas
3
4
. Eremeev, A.P. and Belyaeva, E.M., Kontrol’ mekha-
nizma protsessa parnymi vzaimodeistviyami (Control
of the Mechanism of the Process by Pair Interactions),
Available from ONIITEKhIM, Cherkassy, March 3,
2
2
mixture.
1
980, no. 865-khp-D80.
(2) The optimal conditions were found for syn-
. Eremeev, A.P., Posledovatel’noe planirovanie khimi-
cheskogo eksperimenta s ispol’zovaniem fiziko-khimi-
cheskoi interpretatsii effektov parnykh vzaimodeistvii
(Successive Designing of a Chemical Experiment Us-
ing Physicochemical Interpretation of Pair Interaction
Effects), Available from VINITI, Moscow: November
16, 1981, no. 5245 81.
thesis of p-quinone mono-2,4-dinitrophenylhydrazone:
pressure P 2.5 MPa, temperature T 80 C, con-
densation time
3) The 3D diagram of the response surface and
the revealed regression effect of the X X pair interac-
1 h.
(
1
3
tion (total pressure of the steam gas mixture in the
5. Eremeev, A.P., Zh. Prikl. Khim., 1980, vol. 53, no. 5,
autoclave X and the reaction mass temperature X )
pp. 1134 1135.
1
3
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 76 No. 4 2003