Process for preparation of 3,3'- or 3,4'-diaminobenzophenones

Preparation of 3,3'- or 3,4'-diaminobenzophenone by nitrating a chloronitrobenzophenone mixture obtained by the Friedel-Crafts reaction between 3- or 4-nitrobenzoyl chloride and chlorobenzene, and catalytically reducing and dechlorinating the resulting chlorodinitrobenzophenone mixture in the presence of a reduction catalyst and a dehydrochlorinating agent.

BACKGROUND OF THE INVENTION 
The present invention relates to a novel process for the preparation of 
3,3'- or 3,4'-diaminobenzophenone. 
3,3'-Diaminobenzophenone and 3,4'-diaminobenzophenone are useful as 
monomers for the production of heat-resistant high-molecular compounds, 
intermediates for the production of agricultural chemicals, 
pharmacological compounds and dyes, particularly as starting materials for 
the production of polyamides and polyimides. 
Heretofore, these diaminobenzophenones have been prepared by reducing the 
corresponding dinitrobenzophenones. For example, 3,3'-diaminobenzophenone 
has been prepared by reducing 3,3'-dinitrobenzophenone in the presence of 
a tin compound in a large amount of concentrated hydrochloric acid [L.H. 
Kloron et al., J. Org. Chem., 23, 351(1958)]. 3,4'-Diaminobenzophenone has 
been prepared by reducing 3,4'-dinitrobenzophenone in the presence of a 
tin compound [I. Moyer. Hunsberger et al., J. Am. Chem. Soc., 71, 
2637(1949)]. 
However, it is very difficult to industrialize these processes, because 
there has been no method of advantageously preparing 3,3'- or 
3,4'-dinitrobenzophenone as the starting material. For example, 
3,3'-dinitrobenzophenone may be prepared by nitrating benzophenone, but 
the resulting product is composed of a mixture containing various isomers 
or the like. In order to isolate the desired 3,3'-dinitro compound, large 
amounts of solvents must be used and purification by recrystallization 
must be repeated [E. Barmatt et al., J. Chem. Soc., 125, 767(1924)]. For 
this reason, the yield of 3,3'-dinitrobenzophenone is greatly lowered, and 
complicated stages are required for the recovery of solvents used for the 
purification and for the treatment of residue. 
Recently, it has been proposed a process in which the nitration of 
benzophenone is conducted by using a large amount of oleum to selectively 
nitrate the meta-position. However, this process has problems in the 
disposal of a large amount of waste acid and materials for the apparatus 
[A. Onopchenko et al., J. Org. Chem., 46, 5014(1981)]. 
3,4'-Dinitrobenzophenone may be prepared, for example, by a process in 
which 4-nitrobenzyl alcohol is reacted with nitrobenzene to obtain 
3,4'-dinitrodiphenylmethane which is then oxidized with chromic acid [P.J. 
Montagne, Ber., 49, 2293-2294 (1916)]; a process in which diphenylacetic 
acid is nitrated with fuming nitric acid to obtain 
3,4'-dinitrodiphenylacetic acid which is then oxidized with chromic acid 
[I. Moyer Hunsberger et al., J. Am. Chem. Soc., 71, 2635-2639(1949)]; and 
a process in which 4-nitrobenzophenone is nitrated [Vernon, Li Bell et 
al., J. Org. Polymer, Chem., 14, 2277(1976)]. 
However, these processes have disadvantages in that very complicated 
reactions must be conducted, large amounts of by-products such as isomers 
must be removed, purification by recrystallization must be repeated and 
the disposal of waste acid and waste metals requires much cost. 
Further, the separation of the tin compound used in the reduction of the 
dinitrobenzophenones is troublesome. Care must be taken lest trace amounts 
of the metal should remain. Much cost and effort are required for the 
disposal of waste metal and waste acid to prevent them from causing 
environmental pollution. 
Therefore, the conventional processes of preparing dinitrobenzophenones and 
reducing them to diaminobenzophenones are industrially very unfavourable 
from the viewpoints of economy and environmental protection. Thus an 
improved process for the preparation of 3,4'-diaminobenzophenone, from 
which disadvantages associated with the prior art are eliminated has been 
eagerly seeked. 
SUMMARY OF THE INVENTION 
An object of the present invention is to provide an industrially and 
economically advantageous process for the preparation of 3,3'- or 
3,4'-diaminobenzophenone. 
Another object of the present invention is to provide a process for the 
preparation of 3,3'- or 3,4'-diaminobenzophenone, which does not require 
the troublesome separation and purification operations of intermediate 
compounds in the production of 3,3'- or 3,4'-diaminobenzophenone starting 
from 3- or 4-nitrobenzoyl chloride and chlorobenzene, gives good yields in 
a high purity and makes it possible to prepare the desired products 
inexpensively. 
In accordance with the present invention, it is possible to prepare 3,3'- 
or 3,4'-diaminobenzophenone in a high yield and in a high purity by 
subjecting 3- or 4-nitrobenzoyl chloride and chlorobenzene in the presence 
of a Lewis acid catalyst to the Friedel-Crafts reaction, nitrating the 
resulting mixture of chlorobenzophenone isomers without purifying it, and 
catalytically reducing and dechlorinating the resulting 
chlorodinitrobenzophenone mixture in the presence of a reduction catalyst 
and a dehydrochlorinating agent. 
In accordance with the present invention, the Friedel-Crafts reaction 
between 3- or 4-nitrobenzoyl chloride and chlorobenzene gives an isomer 
mixture which is then nitrated, and the resulting isomer mixture is 
reduced and dechlorinated to give the desired 3,3'- or 
3,4'-diaminobenzophenone. Thus, the desired product can be prepared from 
intermediate products themselves containing various isomers formed in two 
stages (the Friedel-Crafts reaction and nitration reaction) during the 
course of the reaction starting with 3- or 4-nitrobenzoyl chloride and 
leading to 3,3'- or 3'4'-diaminobenzophenone. Namely, the intermediate 
products used in this process need not be separated from undesirable 
isomers to isolate the suitable product. 
DETAILED DESCRIPTION OF THE INVENTION 
The process of the present invention is conducted in the following manner. 
(1) Nitrobenzoyl chloride and chlorobenzene are subjected to the 
Friedel-Crafts reaction in the presence of a Lewis acid catalyst to obtain 
a chloronitrobenzophenone mixture. For example, 3-nitrobenzoyl chloride is 
reacted with chlorobenzene in the presence of anhydrous aluminum chloride 
catalyst to obtain a mixture composed of 4'-chloro-3-nitrobenzophenone and 
2'-chloro-3-nitrobenzophenone. Alternatively, 4-nitrobenzoyl chloride is 
reacted with chlorobenzene in the presence of anhydrous aluminum chloride 
or anhydrous ferric chloride to obtain a mixture composed of 
4'-chloro-4-nitrobenzophenone and 2'-chloro-4-nitrobenzophenone. (2) When 
these mixtures are nitrated, a nitro group is introduced only into a 
metaposition with respect to the carbonyl group of the benzene ring having 
a chloro group. Therefore, the mixture composed of 
4'-chloro-3-nitrobenzophenone and 2'-chloro-3-nitrobenzophenone gives a 
mixture composed of 4'-chloro-3,3'-dinitrobenzophenone, 
2'-chloro-3,3'-dinitrobenzophenone and 2'-chloro-3,5'-dinitrobenzophenone. 
The mixture composed of 4'-chloro-4-nitrobenzophenone and 
2'-chloro-4-nitrobenzophenone gives a mixture composed of 
4'-chloro-3',4-dinitrobenzophenone, 2 '-chloro-3',4-dinitrobenzophenone 
and 2'-chloro-4,5'-dinitrobenzophenone. 
(3) When these mixtures are catalytically reduced and dehalogenated in the 
presence of a reduction catalyst and a dehydrohalogenating agent, only the 
corresponding 3,3'- or 3,4'-diaminobenzophenone can be obtained in a high 
yield industrially ad- vantageously. 
In the process of the present invention, 3-or 4-nitrobenzoyl chloride and 
chlorobenzene are firstly subjected to the Friedel-Crafts reaction 
(hereinafter referred to as the first-stage reaction). In the first-stage 
reaction, chlorobenzene is used in an amount of 1.1 to 3 times by mol that 
of nitrobenzoyl chloride. Any of catalysts which can be used in the 
Friedel-Crafts reaction may be used. Examples of such catalysts include 
Lewis acids such as anhydrous aluminum chloride, anhydrous ferric 
chloride, anhydrous ferric sulfate and boron trifluoride. As to the 
amounts of these catalysts to be used, anhydrous aluminum chloride is used 
in an amount of 1 to 2 mol per mol of nitrobenzoyl chloride, and anhydrous 
ferric chloride, anhydrous sulfate and boron trifluoride are used in an 
amount of 0.005 to 0.1 mol, preferably 0.01 to 0.05 mol per mol of 
nitrobenzoyl chloride. 
The reaction is conducted at a temperature of 0.degree. to 80.degree. C., 
preferably 10.degree. to 60.degree. C., when anhydrous aluminum chloride 
catalyst is used. When anhydrous ferric chloride, anhydrous ferric sulfate 
or boron trifluoride is used as a catalyst, the reaction is conducted at 
the reflux temperature of an excess of chlorobenzene, i.e., at a 
temperature of 140.degree. to 180.degree. C. until the evolution of 
hydrogen chloride gas ceases. The termination of the reaction can be 
ascertained by determining the amount of hydrogen chloride gas evolved, or 
by confirming the amount of the consumed nitrobenzoyl chloride by means of 
gas chromatography or high performance liquid chromatography. 
After the completion of the reaction, an excess of chlorobenzene is 
distilled off under reduced pressure or by steam distillation to obtain a 
crude chloronitrobenzophenone mixture. 
In the subsequent nitration reaction, this chloronitrobenzophenone mixture 
is nitrated to prepare chlorodinitrobenzophenes (hereinafter referred to 
as the second-stage reaction). This second-stage reaction may be conducted 
under the same conditions in all cases irrespective of the contents of the 
2'-chloro and the 4'-chloro compounds in the chloronitrobenzophenone 
mixture obtained in the first stage reaction. 
As the nitrating agents, mixed acid, fuming nitric acid, nitric acid/acetic 
acid and other conventional nitrating agents may be used. Generally, the 
mixed acid and fuming nitric acid are preferred. 
By using these nitrating agents, the second-stage reaction is conducted in 
the following manner. 
When the nitration is conducted with fuming nitric acid, 95% nitric acid is 
used in an amount of 4 to 6 mol per mol of the crude 
chloronitrobenzophenone. When the nitration is conducted with a mixed 
acid, the one comprising a combination of concentrated sulfuric acid and 
nitric acid or a nitrate such as sodium nitrate or potassium nitrate is 
used in a molar ratio of the combined amount of nitric acid or the nitrate 
and concentrated sulfuric acid to the chloronitrobenzophenone of 1:1.1 - 
1.5:2 - 3. 
If necessary, a halogenated hydrocarbon solvent such as dischloromethane, 
1,2-dichloroethane, 1,1,2-trichloroethane, chloroform, carbon 
tetrachloride, 1,1,2,2-tetrachloroethane or trichloroethylene may be used 
in the nitration reaction. 
The reaction is conducted by mixing the crude chloronitrobenzophenone 
mixture, a nitrating agent and, if necessary, a solvent. When the reaction 
is conducted by using a mixed acid as a nitrating agent, the crude 
chloronitrobenzophenone is introduced into the mixed acid which has been 
previously prepared. Alternatively, nitric acid or the nitrate is added to 
a mixture of sulfuric acid and the starting material. The 
chloronitrobenzophenone mixture and the mixed acid are thoroughly mixed 
together. Then the nitration reaction is conducted by heating the mixture 
with stirring. The reaction temperature is in the range of 20.degree. to 
100.degree. C. The reaction time is in the range of 2 to 15 hours. 
The termination of the reaction can be determined by means of thin-layer 
chromatography or high performance liquid chromatography. After the 
completion of the reaction, the chlorodinitrobenzophenone mixture prepared 
in the second-stage reaction can be recovered by any of conventional 
methods. For example, when a solvent is not used, the reaction mixture is 
diluted with water or ice water to precipitate the product which is then 
recovered by filtration. When a solvent is used, the reaction mixture is 
separated into a solvent layer and a waste acid layer, or is diluted with 
water. The solvent is distilled off by steam distillation. The resulting 
product is recovered by filtration. 
As mentioned above, there can be obtained in the second-stage reaction the 
chlorodinitrobenzophenone where the nitro group has been introduced into a 
metaposition with respect to the carbonyl group of the benzene ring having 
a chloro group. When 3-nitrobenzoyl chloride is used as a starting 
material, the product is a mixture consisting of 
4'-chloro-3,3'-dinitrobenzophenone, 2'-chloro-3,3'-dinitrobenzophenone and 
2'-chloro-3,5'-dinitrobenzophenone. When 4-nitrobenzoyl chloride is used 
as a starting material, the product is a mixture consisting of 
4'-chloro-3',4-dinitrobenzophenone, 2'-chloro-3',4-dinitrobenzophenone and 
2'-chloro-4,5'-dinitrobenzophenone. 
Without isolating each of the chlorodinitrobenzophenones, these mixtures 
may be subjected to the subsequent reduction and dechlorination reaction 
(hereinafter referred to as the thirdstage reaction) to prepare the 
desired 3,3'- or 3,4'-diaminobenzophenone. 
The third-stage reaction can be conducted, e.g., in the following manner. 
In case (a), crude chlorodinitrobenzophenones are dissolved or suspended 
in a solvent. A reduction catalyst is added thereto. Then hydrogen is 
introduced into the mixture with stirring at a predetermined temperature 
to effect the reduction of the nitro groups followed by the addition of a 
dehydrochlorinating agent to effect a dechlorination reaction. In case 
(b), the dehydrochlorinating agent is added together with the reduction 
catalyst. Hydrogen is introduced into the mixture with stirring at a 
predetermined temperature to simultaneously conduct the reduction of the 
nitro groups and the dechlorination reaction. In any case the reaction 
proceeds smoothly to form the desired 3,3'- or 3,4'-diaminobenzophenone. 
However, since the chlorine atom of the starting chlorodinitrobenzophenone 
is nucleophilic, a side reaction between the chlorine atom and the 
dechlorinating agent takes place under certain conditions to lower the 
yield of the desired product. Thus, the method (a) is preferred. 
As the reduction catalysts used in the thirdstage reaction, any of 
conventional metal catalysts for catalytic reduction may be used. Examples 
of the metals include nickel, palladium, platinum, rhodium, ruthenium, 
cobalt and copper. Palladium catalyst is industrially preferred. These 
catalysts may be used in a metallic form. Usually, these metals are 
supported on a catalyst carrier such as carbon, barium sulfate, silica gel 
or alumina. Nickel, cobalt or copper may be used in the form of a Raney 
catalyst. 
The catalyst is used in an amount of 0.01 to 10% by weight based on that of 
the crude chlorodinitrobenzophenone. When the catalyst is used in the form 
of a metal, the amount is usually in the range of 2 to 8% by weight. When 
the catalyst is supported on a carrier, the amount is in the range of 0.05 
to 5% by weight. 
As the dehydrochlorinating agents, alkali metal or alkaline earth methal 
oxides, hydroxides and bicarbonates, alkali metal or alkaline earth metal 
salts of lower fatty acids, ammonia and organic amines may be used. 
Examples of such dehydrochlorinating agents are calcium carbonate, sodium 
hydroxide, magnesium oxide, ammonium bicarbonate, calcium oxide, lithium 
hydroxide, barium hydroxide, potassium carbonate, potassium hydroxide, 
sodium acetate, potassium propionate, ammonia, triethylamine, 
tri-n-butylamine, triethanolamine, pyridine, N-methylmorpholine and 
mixtures thereof. 
The dehydrochlorinating agent is used in an amount of 0.2 to 5 times by 
mol, preferably 0.5 to 2 times by mol that of the crude 
chlorodinitrobenzophenone. 
Usually, the reaction is carried out in an organic solvent. Any of organic 
solvents which are inert to the reaction may be used without particular 
limitation. Examples of such solvents include alcohols such as methanol, 
ethanol and isopropyl alcohol; glycols such as ethylene glycol and 
propylene glycol; ethers such as ehter, dioxane, tetrahydrofuran and 
methyl cellosolve; aliphatic hydrocarbons such as hexane and cyclohexane; 
esters such as ethyl acetate and butyl acetate; halogenated hydrocarbons 
such as dichloromethane, chloroform, carbon tetrachloride, 
1,2-dichloroethane, 1,1,3trichloroethane and tetrachloroethane; 
dimethylformamide and dimethyl sulfoxide. When a solvent immiscible with 
water is used and the reaction proceeds too slow, the reaction can be 
accelerated by adding a conventional phase transfer catalyst such as a 
quaternary ammonium salt or a quaternary phosphonium salt. The solvent is 
used in an amount sufficient to suspend or completely dissolve the 
chlorodinitrobenzophenone. Usually, the solvent is used in an amount of 
0.5 to 10 times by weight that of the starting material. 
The reaction temperature is not critical and usually within the range of 
20.degree. to 200.degree. C., preferably 20.degree. to 100.degree. C. The 
reaction pressure is usually within the range of from atmospheric pressure 
to 50 kg/cm.sup.2 G. 
The termination of the reaction can be confirmed by determining the amount 
of hydrogen consumed or by means of thin layer chromatography. After the 
completion of the reaction, the catalyst and inorganic salts are removed 
by filtering the reaction solution with heating or by extraction. If 
necessary, the resulting solution is concentrated to precipitate 3,3'- or 
3,4'-diaminobenzophenone as a crystal. Alternatively, hydrogen chloride 
gas is bubbled through the reaction solution after the removal of the 
catalyst and the inorganic salts to isolate the product as 3,3'- or 
3,4'-diaminobenzophenone hydrochloride.

The following examples further illustrate the present invention in more 
detail. 
EXAMPLE 1 
2.7 g (0.02 mol) of anhydrous ferric chloride was added to a mixture of 
185.5 g (1.0 mol) of 3-nitrobenzoyl chloride and 124 g (1.1 mol) of 
chlorobenzene. While introducing nitrogen gas into the reactor, the 
reaction was conducted with stirring at a temperature of 140.degree. to 
150.degree. C. for 19 hours. After the completion of the reaction, an 
excess amount of chlorobenzene was distilled at the same temperature under 
reduced pressure to recover it. Then the reaction mixture was cooled to 
80.degree. C. and 500 ml of 1,2-dichloroethane was added thereto to form a 
homogeneous solution. While keeping the temperature at 70.degree. to 
75.degree. C., 335 g (5 mol) of 94% nitric acid (d =1.50) was added 
dropwise to the above solution over a period of two hours. After the 
completion of the addition, the reaction was continued at the reflux 
temperature of 1,2-dichloroethane for 12 hours to complete the nitration 
reaction. 1,2-Dichloroethane was distilled off to precipitate light brown 
particulate chlorodinitrobenzophenone. This product was recovered by 
filtration, washed with water, and dried to give 286 g (over-all yield 
93.2%) of crude chlorodinitrobenzophenone. 
The analysis by means of high performance liquid chromatography revealed 
that the crude reaction product consisted of the following composition: 
______________________________________ 
4'-chloro-3,3'-dinitrobenzophenone 
82.8% 
2'-chloro-3,3'-dinitrobenzophenone 
12.4% 
2'-chloro-3,5'-dinitrobenzophenone 
other products 5.8% 
______________________________________ 
30.7 g (0.1 mol) of this crude chlorodinitrobenzophenone, 0.31 g of 5% Pd/C 
(a product of Nippon Engelhardt K.K.) and 200 ml of ethanol were charged 
in a closed glass vessel equipped with a thermometer and a stirrer. While 
vigorously stirring the mixture at 45.+-.2.degree. C., hydrogen was 
introduced thereinto and 11.76 l(0.525 mol) of hydrogen was absorbed in 7 
hours. The reaction mixture was cooled to 30.+-.2.degree. C. and 11 g of 
28% aqueous ammonia was added thereto. Hydrogen was introduced at the same 
temperature and 3.84 l (0.17 mol) of hydrogen was absorbed in 5 hours. 
After the completion of the reaction, the temperature of the reaction 
mixture was raised to 75.degree. to 80.degree. C. The catalyst and 
contaminants were removed by filtering the reaction mixture with heating. 
The filtrate was cooled to precipitate 3,3'-diaminobenzophenone as a 
yellow crystal. The crystal was recovered by filtration, washed with a 50% 
aqueous ethanol solution, and dried to give 15.3 g (yield 72.2% based on 
the crude chlorodinitrobenzophenone) of a product with m.p. of 148.degree. 
to 149.5.degree. C. This product was recrystallized from water to give 
pure 3,3'-diaminobenzophenone as a light yellow needle crystal with m.p. 
of 149.degree. to 150.degree. C. 
Elemental analysis: Calculated (%): C73.5, H5.7, N13.2. Found (%): C73.5, 
H5.8, N13.2. 
EXAMPLES 2 to 4 
146.6 g (1.1 mol) of anhydrous aluminum chloride was added to a mixture of 
185.5 g (1.0 mol) of 3-nitrobenzoyl chloride and 225 g (2.0 mol) of 
chlorobenzene. The reaction was conducted at a temperature of 50.degree. 
to 60.degree. C. for 3 hours. After the completion of the reaction, the 
contents were poured into 2 l of ice water. The resulting organic layer 
was separated and subjected to steam distillation to distill off an excess 
amount of chlorobenzene and to precipitate greyish white particulate 
chloro-nitrobenzophenone. This product was recovered by filtration, washed 
with water, and dried to give 252.7 g (crude yield 96.6%) of crude 
chloro-nitrobenzophenone. 
This crude chloronitrobenzophenone was dissolved in 500 ml of methylene 
chloride and 250 g (2.5 mol) of concentrated sulfuric acid and 93.5 g (1.1 
mol) of sodium nitrate were added thereto. The mixture was reacted at a 
temperature of 35.degree. to 40.degree. C. for 7 hours. After the 
completion of the reaction, 500 ml of ice water was carefully added 
thereto. Methylene chloride was removed by heating. The precipitated light 
brown particulate material was recovered by filtration, washed with water, 
and dried to give 293 g (over-all yield 95.5%) of crude 
chlorodinitrobenzophenone. 
The analysis by means of high performance liquid chromatography revealed 
that the crude reaction product consisted of the following composition: 
______________________________________ 
4'-chloro-3,3'-dinitrobenzophenone 
96.7% 
2'-chloro-3,3'-dinitrobenzophenone 
3.1% 
2'-chloro-3,5'-dinitrobenzophenone 
other products 0.2% 
______________________________________ 
Then the experiment of Example 1 was repeated except that the amount of the 
crude chlorodinitrobenzophenone, the catalysts, the solvents, the 
dehydrochlorinating agents and pressures given in Table 1 were employed. 
The results are shown in Table 1. 
EXAMPLE 5 
4 g (0.03 mol) of ferric chloride was added to a mixture of 185.5 g (1.0 
mol) of 4-nitrobenzoyl chloride and 135 g (1.2 mol) of chlorobenzene. 
While introducing nitrogen gas into the reactor, the reaction was 
conducted with stirring at a temperature of 140.degree. to 155.degree. C. 
After the completion of the reaction, the reaction mixture was cooled to 
90.degree. C. and 200 ml of hot water was added thereto. An excess amount 
of chlorobenzene was recovered by steam distillation. Then the contents 
were cooled and the product was recovered by filtration and dried to give 
246.7 g (crude 94.3%) of brown particulate crude chloronitrobenzophenone. 
This crude chloronitrobenzophenone was nitrated at a temperature of 
50.degree. to 60.degree. C. for 3 hours by using a mixed acid consisting 
of 250 g (2.5 mol) of concentrated sulfuric acid and 80 g (1.2 mol) of 94% 
nitric acid (d =1.50). After the completion of the reaction, the reaction 
mixture was cooled and poured into 2 l of ice water. The product was 
recovered by filtration and dried to give 283.9 g (over-all yield 92.6%) 
of pale brown particulate crude chlorodinitrobenzophenone. 
The analysis by means of high performance liquid chromatography revealed 
that the crude reaction product consisted of the following com- position: 
______________________________________ 
4'-chloro-3',4-dinitrobenzophenone 
86.2% 
2'-chloro-3',4-dinitrobenzophenone 
10.7% 
2'-chloro-4,5'-dinitrobenzophenone 
other products 3.1% 
______________________________________ 
Then the experiment of Example 1 was repeated in all essential details 
except that the amount of the crude chlorodinitrobenzophenone, the 
catalysts, the solvents, the dehydrochlorinating agents and pressures 
given in Table 1 were employed. The results are shown in Table 1. 
EXAMPLE 6 
The experiment of Example 5 was repeated except that 4-nitrobenzoyl 
chloride was used as a starting material. 294.3 g (over-all yield 96%) of 
crude chloronitrobenzophenone was obtained. The analysis by means of high 
performance liquid chromatography revealed that the crude reaction product 
consisted of the following composition: 
______________________________________ 
4'-chloro-3',4-dinitrobenzophenone 
96.3% 
2'-chloro-3',4-dinitrobenzophenone 
3.4% 
2'-chloro-4,5'-dinitrobenzophenone 
other products 0.3% 
______________________________________ 
30.7 g (0.1 mol) of this crude chlorodinitrobenzophenone, 1 g of palladium 
black catalyst (a product of Nippon Engelhardt K.K.) and 100 ml of 
isopropyl alcohol were charged in the same reactor as that of Example 1. 
While vigorously stirring the mixture at a temperature of 25.degree. to 
30.degree. C., hydrogen was introduced thereinto and 10.2 l (0.455 mol) of 
hydrogen was absorbed in 10 hours. Then 12.2 g (0.12 mol) of triethylamine 
was added and hydrogen was introduced thereinto. 5.2 l (0.232 mol) of 
hydrogen was absorbed in 5 hours. After the completion of the reaction, 
the temperature of the reaction mixture was raised to 70 to 80.degree. C. 
The catalyst and contaminants were removed by filtration with heating. The 
filtrate was cooled to precipitate 3,4'-diaminobenzophenone as a yellow 
crystal. This crystal was recovered by filtration, washed with 15 ml of 
isopropyl alcohol, washed with water, and dried to give 17.7 g (yield 
83.5%) of a product with m.p. of 126.5.degree. C. This product was 
recrystallized from water to give pure 3,4'-diaminobenzophenone as a pale 
yellow needle crystal with m.p. of 126.3.degree. to 127.9.degree. C. 
Elemental analysis: Calculated (%): C73.5, H5.7, N13.2. Found (%): C73.4, 
H5.7, N13.1. 
EXAMPLE 7 
30.7 g (0.1 mol) of crude chlorodinitrobenzophenone obtained in Example 6, 
1.5 g to 5% Pd/C 22.2 g (0.3 mol) of calcium hydroxide, 800 ml of 
methylene chloride and 1 g of a 90% aqueous solution of 
trioctylmethylammonium chloride (a reagent of Tokyo Kasei K.K.) were 
charged in an autoclave. While vigorously stirring the mixture at a 
temperature of 35.degree. to 40.degree. C., hydrogen was introduced and 
the pressure was kept at 10 to 12 kg/cm.sup.2 G. The reaction was 
continued for 11 hours. The catalyst and contaminants were removed by 
filtration. An organic layer was separated from the filtrate. Hydrogen 
chloride gas was bubbled through the organic layer until the layer was 
saturated. The precipitated crude crystal was recovered by filtration. 
Yield: 21.8 g (76.5%). This crystal was recrystallized from a 20% aqueous 
isopropyl alcohol solution to give 3,4'-diaminobenzophenone hydrochloride 
as a light yellowish white needle crystal with m.p. above 250.degree. C. 
Elemental analysis: Calculated (%): C54.7, H4.9, N9.8, Cl24.9. Found (%): 
C54.5, H5.0, N9.9, Cl24.7. 
EXAMPLE 8 
The experiment of Example 1 was repeated in all essential details except 
that the amount of. the crude chlorodinitrobenzophenone obtained in 
Example 6, the catalysts, the solvents, the dehydrochlorinating agents and 
pressure given in Table 1 were employed. The results are shown in Table 1. 
TABLE 1 
__________________________________________________________________________ 
Starting Dehydrochlorinating Desired 
Example 
material 
Catalyst Solvent agent Temperature 
Pressure 
Time 
product 
No. (mol) 
(g) (ml) (mol) (.degree.C.) 
(kg/cm.sup.2.G) 
(hr) 
yield 
__________________________________________________________________________ 
(%) 
2 0.1 5% Pt/C 1.5 
dioxane 
100 
20% aqueous 
0.1 
70.about.80 
normal 
18 3,3'-DABP* 
caustic soda pressure 81.6 
solution 
3 0.1 Raney nickel 
3 ethyl 100 
magnesium 
0.08 
95.about.100 
5.about.7 
10 3,3'-DABP 
cellosolve 
chloride 80.6 
4 0.1 5% Pd/C 0.3 
THP 60 
sodium acetate 
0.16 
20.about.30 
normal 
9 3,3'-DABP 
pressure 80.1 
5 0.1 5% Pd/C 0.6 
isopropanol 
100 
20% aqueous 
0.12 
30.about.45 
normal 
15 3,4'-DABP 
ammonia pressure 74.7 
8 0.1 5% Pd--Rh/C 
0.6 
methanol 
60 
calcium carbonate 
0.1 
30.about.45 
normal 
18 3,4' -DABP 
pressure 82.5 
__________________________________________________________________________ 
*Note: 
DABP = diaminobenzophenone