Note: Descriptions are shown in the official language in which they were submitted.
a~
~L~
The present invention rélatés to a novel process
for the preparation of 3,3'- or 3,4'-diaminodiphenyl~
methaneO
3,3'-Diaminodiphenylmethane and 3,4'-diamino-
diphenylmethane are useful as monomers for the produc-
tion of high-molecular compounds, intermediates for
the production of agricultural chemicals, pharmaco-
logical compounds and dyes, particularly useful as
starting materials for the production of polyamides
and polyimides having excellent heat resistance.
Herefore, 3,3'-diaminodiphenylmethane has been
prepared by condensing 3-nitrobenzyl alcohol with
nitrobenzene or condensing nitrobenzene with formal-
dehyde to prepare 3,3'-dinitrodiphe~ylmethane which
is then reduced in the presence of stannic chloride
or iron [ L. Gatterman et al., Ber., 27, 2295 (1894);
L. Thorp et al. 9 J. Am. Chem. Soc., 37, 373 (1915);
M. Schopff et al., Ber., 27 9 2322 (1894~ ~.
3,4'-Diaminodiphenylmethane has been prepared
by condensing 4-nitrobenzyl alcohol with nitrobenzene
to prepare 3,4'-dinitrodiphenylmethane which is then
reduced [ L. Gattarmann et al., Ber., 27, 2293 (1894) ].
However, even when the condensation reaction
between benzyl alcohol and nitrobenzene or between
nitrobenzene and formalin is conducted for a long
period of time by using a large amount of concentrated
sulfuric acid, these processes result in yields of
dinitrodiphenylmethane of as low as only 20 to 30 %.
Further, dinitrodiphenylmethane must be reduced in
the presence of a tin compound or iron to obtain
diaminodiphenylmethane. But, it is bothersome to
separate the metallic compound used for the reduction
from the product and it is necessary to Pay attention
lest trace amounts of the me-tal should remain in the
product.
Thus the conventional processes of preparing
dinitrodiphenylmethane by the known condensation
reaction and reducing it to prepare diaminodiphenyl-
methane have disadvantages in that they require much
cost and effort for the disposal of a large amount of
various waste materials to prevent them from causing
environmental pollution or for the recovery of them~
and in addition thereto the desired product is
obtained in a low yieldO Accordingly, these processes
are industrially unfavorable from the viewpoints of
economy and environmental protection.
An object of the present invention is to provide
an industrially advantageous and economical process
for the preparation o~ 3,3'- or 3,4'~diaminodiphenyl-
methane.
Another object o~ the present invention is to
provide a process for -~he preparation of 3,3'- or
3,4'-diaminodiphenylmethane in a high yield.
Still another object of the present invention
is to provide a process which does not require much
cost and effort as compared with the conventional
processes for the disposal of a large amount of various
waste materials, formed as by-products in manufacturing
processes, to prevent them from causing environmental
pollution and which is excellent in the viewpoint of
environmental protection.
In accordance with this invention, it is possible
to prepare 3,3'- or 3,4'-diaminodiphenylmethane by
catalytically reducing and dechlorinating, in the
presence of a reduction catalyst 9 a dinitrobenzophenone
having the formula
X~ ~Y
N2 N02
wherein X is chlorine and attached to a position 4
or 6 on the benzene ring, Y is hydrogen or chlorine
with the proviso that when Y is hydrogen, the nitro
~21~ 9
,
group is attached to a positinn 3~ or 4', and when Y
is chlorine, Y is attached to a position 4' and the
nitro group is attached to a position 3'.
The process of the present invention has advan-
tages in that it does not require much cost and effort
for the disposal of a large amount of various was-te
materials to prevent them from causlng environmental
pollution or for the recovery of them and in addition
thereto the desired product can be prepar~d in a high
yield, while the conventional processes of preparing
3,3'- or 3,4'-dinitrodiphenylmethane by the known
condensation reaction and reducing it require much
cost and effort.
m e process of the present invention comprislng
dechlorinating a dinitrochlorobenzophenone compound
as ~educing its nitro groups and further converting
its carbonyl group into a methylene group is not known
by those skilled in the art. Therefore, -the present
invention provides a novel process for the preparation
of 3,3'- or 3,4'-diaminodiphenylmethane which can be
prepared industrially advantageously.
~=~3
The present invention relates to a process for
the preparation of 3,31_ or 3,4'-diaminodiphenylmethane
by catalytically reducing and dechlorinating, in the
-- 4 --
L4~
presence of a reduction catalyst, the dinitrobenzo-
phenone compound represented by the above formula to
obtain 3,3'- or 3,4'-diaminodiphenylmethane hydrochlo-
ride followed by neutralization with ammonia or an
amine.
Typical dinitrobenzophenones that can be used
as starting materials in the practice of the present
invention include 3,3'-dinitro-4,41-dichlorobenzophenone,
3,3'~dinitro-6,4'-dichlorobenzophenone, 3,3'-dini-tro-
6-chlorobenzophenone, 3,3'-dinitro-4-chlorobenzophenone,
3,4'-dinitro-6-chlorobenzophenone and 3,4'-dinitro~4-
chlorobenzophenone.
These dinitrobenzophenones can be easily obtained
by nitrating the corresponding halogenobenzophenones
such as 4,4'-dichlorobenzophenone, 4-chlorobenzophenone,
4-nitro-6'-chlorobenzophenone, 4 chloro-4'-nitro
benzophenone and 2,4'~dichlorobenzophenone.
For example, 3,3'-dinitro-4 9 4'-dichlorobenzo-
phenone can be prepared in a yield of 95 to 98 % by
nitrating 4,4'-dichlorobenzophenone ~ E. R. Kofanov
e-t al., J. Org. Chem. USSR, 15, 98-lOO (1979) ].
5,3'-Dinitro-2,4'--dichlorobenzophenone can be prepared
in a high yield by nitrating 2,4'-dichlorobenzophenone
[ E. H. Faith et al., J. Am. Chem. Soc., 779 543
(1955) ]. 3,3'-Dinitro 4-chlorobenzophenone can be
69
prepared in a high yield by nitrating 4-chlorobenzo-
phenone ~ G. S Mironov et al., J, Org. Chem, USSR,
8, 1533 (1972) ~. 3,4'-Dinitro-4-chlorobenzophenone
can be prepared by nitrating 4-halogeno~4~-nitrobenzo-
phenone obtained by the condensation reaction between
p-nitrobenzoyl chloride and chlorobenzene [ P. T.
Montagne et al., Ber., 49, 2267-2270 (1916); G. S.
Mironov et al,, J. Org. Chem. USSR, 8, 1538-1543
(1972) ]. 3,3l-Dini-tro-694'-dichlorobenzophenone can
be prepared in a high yield by nitrating 2,4'-dichloro-
benzophenone obtained by the condensation reaction
- between 2-chlorobenzoyl chloride and chlorobenzene
[ H. F. Faith et al., J Am. Chem. Soc., 77, 543
(1955) ].
As reduction catalysts suitable for use in the
practice of the present invention, metal catalysts
which are conventionally used in cataly-tic reduction
may be used. Examples of the metals are nickel,
palladium, platinu~l, rhodium, ruthenium9 cobalt and
iron. Palladium catalyst is industrially pre~erred.
These catalysts may be used in a metallic ~o~m, but
they are generally supported on a carrier such as
carbon, bariu~ sulfate, silica gel or alumina.
Nickel, cobalt and copper may be used in the form of
a Raney catalyst.
~ :`
~211~691
The catalyst is used in an amount of from 0.05
to 10 % by weight based on that of the starting
dinitrobenzophenone. When the catalyst is used in a
metallic form, the amount is usually within the range
5 of from 2 to 10 ~ by weight. When supported on a
carrier, the amount is within the range of from 0.1
to 5 % by weight.
Generally~ the reaction of the present invention
is conducted in an organic solvent. Any o~ organic
solvents which are inert to the reaction of the pre~
sent invention may be used without particular limita-
tion. Examples of such organic solvents include
alcohols such as methanol, ethanol and isopropyl
alcohol; glycols such as ethylene glycol and propylene
glycol; ethers such as ether, dioxane, tetrahydrofuran
and methyl cellosolve; aliphatic hydrocarbons such as
hexane and cyclohexane; aromatic hydrocarbons such as
benzene, toluene and xylene; esters such as ethyl
acetate and butyl acetate; halogenated hydrocarbons
such as dichloromethane, chloroform, carbon tetrach-
loride, 1,2-dichloroethane, 1,1,2-trichloroethane and
tetrachloroethane; N,N-dimethylformamide and dimethyl
sulfoxide. Hydrogen chloride or hydrochloric acid
in a molar ratio of 1 to 2 may be previously added to
these solvents to carry out the reduction of the
present invention. When an organic solvent immiscible
with water is employed and the reaction proceeds too
slow, the reaction can be accelerated by adding a
conventional phase transfer catalyst such as a qua-
ternary ammonium salt or a quaternary phosphonium
salt, The solvent is used in an amount sufficient
to suspend the starting dinitrobenzophenones or to
completely dissolve them. There is no particular
upper limit for the amount of~-the solvent to be used,
but the solvent is usually used in an amount o~ 0.5
to 10 times by weight that of the starting material.
The reac-tion temperature is usually within the
range of from 20 to 200C, preferably 50 to 150C.
The reaction pressure is usually within the range
of from atmospheric pressure to 50 kg/cm2 G.
In the practice of the present i~vention, the
dinitrobenzophenone compound is suspended or dissolved
in a solvent and a reduction catalyst is added there-to.
Hydrogen is introduced into the mixture with stirring
at a predetermined temperature to convert the nitro
groups into amino groups and the carbonyl group into
a methylene group and to e~fect dechlorination, thus
obtaining 3,3'- or 3,4'-diaminodiphenylmethane
hydrochloride~
The reaction mixture is filtered to recover a
~Zl~L4~9
mixture composed of the desired hydrochloride and the
catalyst. Then the mlxture is dissolved in a 70-90 %
aqueous isopropyl alcohol solution with heating, and
filtered. The filtrate is cooled to precipitate pure
3,3'- or 3,4'-diaminodiphenylmethane hydrochloride
which is then isolated by filtration. The isolated
hydrochloride is dissolved in water and then neutra-
lized to give free 3,3'- or 3,4'-diaminodiphenylmethane~
The progress of the reaction can be traced by
the absorption of a theoretical amount of hydrogen
or by means of thin layer chromatography.
me following examples ~urther illustrate the
present invention in more detail.
Example 1
34.1 g (0 1 mol) of 3,3'-dinitro-4,4' dichloro-
benzophenone, 3.4 g o~ 5 % Pd/C catalyst (a product
of Nippon Engelhardt K.K.) and 100 m~ of dioxane were
charged in a closed glass vessel equipped with a
thermometer and a stirrer. While stirring the mix-ture
at a temperature of 80 to ~5C, hydrogen was introduced
thereinto and 21.8 ~ (0.97 mol) of hydrogen was absorbed
in 10 hours. Since no more absorption of hydrogen
was observed, the reaction was terminated at this point.
The reaction mixture was cooled to room tempera-
ture. A precipitate was rec.overed by filtration and
_ g _
~2~
washed with 10 mB of dioxane to obtain a black filter
cake. This filter cake was dissol~ed in 100 m~ of
an 80 % aqueous isopropyl alcohol solution with heating.
The solution was filtered with heating to remove the
catalyst. The filtrate was cooled -to precipitate
3,3'-diamino-diphenylmethane dihydrochloride as a white
needle crystal. This product was recovered by filtra-
tion, washed with 10 mB of a 90 ~ aqueous isopropyl
alcohol solution, and dried to give 20~3 g (yield
75 ~) of pure 3,3'-diaminodiphenylmethane dihydro-
chloride as a white needle crystal with m.p. above
260C.
Elementary analysis for C13H16N2Ca2:
calculated (%): C 57.6, H 6.09 N 10.3, C~ 26.1
found (%): C 57.4, H 6.1, N 10.3, CB 25.9
Example 2
34.1 g (0.1 mol) of 3j3'-dinitro 4,4'-dichlor-
benzophenone, 1.5 g of 5 % Pd/C9 and 100 m~ of ethanol
were charged in a closed glass vessel equipped with
a thermometer and a stir~er. While stirring the
mixture at a temperature of 50 to 60C 3 hydrogen was
introduced thereinto and 22.9 ~ (1.02 mol) of hydrogen
was absorbed in 7.5 hours. Since no more absorption
of hydrogen was observed, the reaction was terminated
at this point, The reaction solution was neutralized
-- 10 --
with 13.4 g (0,22 mol) of 28 % aqueous ammonia and
fil-tered to remove the catalyst. The filtrate was
concentrated -to give 3,3'~diaminodiphenylmethane as
a brown oil. A high performance liquid chromatography
revealed that the purity was 93.8 %.
This brown oil was vacuum-distilled to give 16.8
g (yield 85 %) of a fraction having a boiling point
of 228 to 229C/5 mmHg. The purity was 99.9 %.
This fraction was recrystallized from benzene
to give a pure product as a white prismatic crystal
with m.p, of 84.5 to 85C.
Elementary analysis for C13H14N2:
calculated (%): C 78.7, H 7.1, N 14.1
found (%): C 78~7, H 7.2, N 14.1
Example 3
34.1 g (0.1 mol) of 3,3' dinitro-6,4'-dichloro-
benzophenone, 1 g of palladium black catalyst and
100 mB of ethyl cellosolve were charged in a closed
glass vessel equipped with a thermometer and a stirrer.
While stirring the mixture at a temperature of 75 to
80C, hydrogen was introduced thereinto and 22.3 ~
(1.0 mol) of hydrogen was absorbed in 5 hours. Since
no more absorption of hy~rogen was observed, the
reaction was terminated at this point. The reaction
solution was neutralized with 42 g (0.21 mol) of a
`~2~L~9L6~
20 % aqueous caustic soda solution and filtered to
remove the catalyst. m e filtrate was concentrated
and vacuum-distilled to give 15 6 g (yield 78.7 ~)
of a fraction having a boiling point of 228 to 229C/
5 mmHg.
Purity: above 99.9
Example 4
15~3 g (0.05 mol) of 3,3'-dinitro-4-chloroben-
zophenone, 1.5 g of 10 % Pt/C and 50 m~ of diethylene
glycol dimethyl ether were charged in an autoclave.
While stirring the mixture at a temperature of 100
to 110C, hydrogen was introduced. m e reaction was
conducted for two hours while keeping the pressure
at 10 Kg/cm2G. After the completion of the reaction,
the reaction mixture was cooled and neutralized with
3.7 g (0.06 mol) of 28 % aqueous ammonia. The catalyst
was removed by filtration. The filtrate was concen~
trated and vacuum-distilled to give 7.9 g (yield
79 8 %) of a fraction having a boiling point o~ 228
to 229oc/5 mmHg.
Example 5
30.7 g (0.1 mol) of 3,3'-dinitro-4-chlorobenzo-
phenone~ 1 5 g of 5 ~ Pd/C and 100 mB o~ ethanol were
charged in a closed glass vessel equipped with a
thermometer and a stirrer. While stirring the mixture
- 12 -
at a temperature of 65 to 70C, hydrogen was introduced
thereto and 20.1 ~ (0~9 mol) of hydrogen was absorbed
in 6 hours. Since no more absorption of hydrogen
was observed, the reaction was terminated at this point.
The reaction mixture was cooled to room -temperature
and filtered to obtain a black filter cake. This
filter cake was dissolved in lO0 mB of a 90 % aqueous
isopropyl alcohol solutiQn with heating. The catalyst
was removed by filtra-tion with heating. The filtrate
was cooled to precipitate 3,3'-diaminodiphenylmethane
hydrochloride as a crystal. This crystal was recovered
by fil-tration, washed with lO m~ of isopropanol and
neutralized with dilute aqueous ammonia to precipitate
a white crystal. The crystal was recovered by filtra-
tion and dried in vacuo to give 1603 g (yield 82.2 %)
of 3,3' diaminodiphenylmethane.
Examples 6 to 9
The experiment of Example 2 was repeated except
that the catalysts, the solvents, the reaction tempe-
ratures and the pressures given in Table l were
employed to give the desired product.
- 13
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t-
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a) ^ ~ ~ ~ ~ a
:~ ~ ~ Pl ~
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~) bl ~ ~ a~ ~ ~ r~
O ~ 0 P1 td
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a~ ~ ,_ ~ ~1
~o O O O O
~j _ O 1~ C-- 1
+'
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~: ~o ~ o ,~o a~o
a~ a~u~ o oo ~0
a~ ~ ~ ~ td
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b~ ~1 ~
h . ~ ~Z
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Example 10
15.3 g (0.05 mol) of 3,4'-dinitro-4-chlorobenzo-
phenone, 0.75 g of 5 % Pd/C and 50 mB of ethyl cellosolve
were charged in a closed glass vessel equipped with a
thermometer and a stirrer. While stirring the mixture
at a temperature of 75 to 80 C, hydrogen was introduced
thereinto and 10.3 ~ (0.46 mol) of hydrogen was absorbed
in 13 hours. Since no more absorption of hydrogen was
observed, the reaction was terminated at this point.
The reaction solution was neutralized with 3,6 g (0.06
mol) of 28 % a~ueous ammonia. The catalyst was removed
by filtration. The filtrate was concentrated to obtain
3,4'-diaminodiphenylmethane as a brown oil. A high
performance liquid chromatography revealed that the
purity was 88.2 %.
This brown oil was vacuum-distilled to give 7.9 g
(yield 79.7 %) of 3,4'-diaminodiphenylmethane having a
purity of 9907 ~ according to a high performance liquid
chromatography
This product was recrystallized from water to give
a pure product as a white needle crystal with m.p. o~
85 to 87C.
Elementary analysis for C13HlLN2:
calculated (%): C 78.7, H 7.1, N 14.1
found (%): C 7805, H 7.1, N 14~0
- 15 -
-
:~2~4~9
Example 11 ! i
m e reduction of 15.3 g (0.05 mol) of 3,4'-dinitro-
4 chlorobenzophenone was conducted in a similar manner
to that of Example 10. After the completion of the
reaction, the catalyst was immediately removed by
filtration with heating. 5.2 g (0.05 mol) of concen-
tra-ted hydrochloric acid was added to the filtrate.
Upon cooling, a light brown needle crystal was preci-
pitated. The crystal was recovered by filtration,
washed with isopropanol, and dried to give 8.9 g ~yield
66 ~) of 3,4'-diaminodiphenylmethane hydrochloride.
This crude crystal was recrystallized ~rom aqueous
isoprpanol solution to give pure 3,4~-diaminodiphenyl-
methane hydrochloride as a white crystal with m.p.
above 210 C ~slowly decomposed)
Elementary analysis for C13H16N2C~2:
calculated (%): C 57.6, H 6.0, N 10.3, C~ 26.1
found (%) : C 57.3, H 6.2, N 10.2, CB 25.9
