JPS5811944B2 - N-p-aminobenzyl-N'-p-aminophenyl urea and its production method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The first invention of this application is N-p-aminobenzyl-N'-p-aminophenyl urea represented by:

The second invention of this application is to produce N-p-nitrobenzyl represented by the formula by reacting p-nitrobenzylamine and p-nitrophenyl isocyanate in an aromatic hydrocarbon at a temperature in the range of 0 to 140°C. In the first step of producing -N'-p-nitrophenyl urea, the compound represented by the formula [■] is heated at 0 to 140°C in an organic solvent selected from amides, aliphatic alcohols, and aliphatic ethers. The second step is reduction at a temperature within a range.

The compound represented by the formula [■] and the compound represented by the formula [■] are both new compounds that have not been described in any literature, and the compound represented by the formula [■]
The compound represented by ] is useful as a component of diamine for producing aromatic polyamide.

Next, a method for producing the compound represented by formula [■] will be specifically explained.

[First step] In the first step, p-nitrobenzylamine and p-
By reacting with nitrophenyl isocyanate, the formula [■]
A compound represented by is produced.

The amount of p-nitrobenzylamine used is usually 0.5 to 2 mol per 1 mol of p-nitrophenyl isocyanate.
Preferably it is about 1 mol.

Specific examples of aromatic hydrocarbons include benzene, toluene,
Examples include xylene.

The amount of aromatic hydrocarbon used is usually 0.5 to 21 per mole of p-nitrobenzylamine.

The reaction between p-nitrobenzylamine and p-nitrophenyl isocyanate can also be carried out by adding both to an aromatic hydrocarbon at the same time. It can also be carried out by gradually adding an aromatic hydrocarbon containing an amine.

The reaction temperature is 0 to 140°C, preferably 50 to 100°C.

If the reaction temperature is lower than 0°C, the reaction rate will be low, which is not preferable, and if the reaction temperature is higher than 140°C, decomposition of p-nitrobenzylamine will occur, which is not preferable.

The reaction time is usually 30 minutes to 4 hours.

As the reaction progresses, a compound represented by formula [■] precipitates out.

After the completion of the reaction, the precipitated compound represented by the formula [■] can be separated by filtration, washed with benzene, toluene, xylene, carbon tetrachloride, etc., and then dried to provide a crude product for the second step. For example, it is preferable to recrystallize from a mixed solvent of ethyl alcohol and acetone and then dry a yellowish-white purified product to be subjected to the second step.

[Second Step] In the second step, the compound represented by the formula [■] is reduced in a hydrogen atmosphere to produce the compound represented by the formula [■].

The reduction reaction is carried out in an organic solvent selected from amides, aliphatic alcohols and aliphatic ethers.

Specific examples of amides include N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethylpropionamide, and N,N,N'.

N'-tetramethylurea, N-methylcaprolactam,
N-methyl-2-pyrrolidone, N-acetyl-2-pyrrolidone, etc. can be mentioned, and specific examples of aliphatic alcohols include methyl alcohol, ethyl alcohol,
Examples of the aliphatic ether include propyl alcohol, and specific examples of the aliphatic ether include diethyl ether and diisopropyl ether.

The amount of organic solvent used is usually 0.5 to 201 moles of the compound represented by formula [■].

Although the reduction reaction can be carried out without a catalyst, it is preferably carried out in the presence of a catalyst such as palladium or nickel.

The amount of the catalyst used is preferably 0.1 to 5 parts by weight per 100 parts by weight of the compound represented by formula [■].

The catalyst is placed on a carrier such as carbon, silica, alumina, etc.
It is desirable to carry 1 to 10 parts by weight per 00 parts by weight.

The reduction reaction temperature is 0 to 140°C, preferably 20 to 100°C.
It is ℃.

If the reduction reaction temperature is lower than 0°C, the reaction rate will decrease, which is undesirable, and if the reduction reaction temperature is higher than 140°C, dehydrogenation of the benzene ring of the compound represented by formula [■] may occur, which is undesirable. .

The reduction reaction is usually carried out under a hydrogen pressure of 1 to 100 Kg/cm2 (absolute pressure), preferably 5 to 50 Kg/cm2 (absolute pressure).

The reaction time is usually 30 minutes to 10 hours.

Isolation of the compound represented by formula [■] from the reaction product mixture can be carried out, for example, as follows.

The catalyst is filtered off from the reaction mixture and then the organic solvent is removed by distillation.

The distillation residue is added to water, the precipitated crystals are filtered off, and then the crystals are dissolved in an aqueous solution of hydrochloric acid, sulfuric acid, phosphoric acid, etc., and this solution is brought into contact with activated carbon or activated clay to undergo a decolorization treatment.

The decolorization treatment is preferably carried out in the presence of a small amount of hydrosulfide.

Thereafter, when a basic compound such as sodium hydroxide or potassium hydroxide is added to the solution obtained by filtering the activated carbon or activated clay to neutralize it, a white compound represented by the formula [■] is precipitated.

The precipitated compound represented by formula [■] is filtered off and then dried.

In the above isolation method, it is preferable that the filtration and drying of the crystals after the neutralization treatment be carried out under an atmosphere of an inert gas such as nitrogen in order to prevent coloring of the crystals.

In the above isolation method, since unreacted N-p-nitrobenzyl-N'-p-nitrophenyl urea is insoluble in the above acid aqueous solution, it is separated by filtration together with activated carbon after decolorization treatment.

Next, examples and reference examples will be shown.

In the examples, infrared absorption spectra of compounds were determined by the KBr tablet method.

Example Synthesis of N-p-nitrobenzyl-N'p-nitrophenyl urea; 4.10 g of p-nitrophenyl isocyanate was dispersed in 150 ml of dehydrated toluene with stirring, and this suspension was
Heated to 0-70°C.

A solution of 3.80 g of p-nitrobenzylamine dissolved in 70 ml of toluene was added to this suspension over 1 hour with stirring, and stirring was then continued for an additional 2 hours.

The produced yellow precipitate was filtered, washed with 30 ml each of hot carbon tetrachloride and hot benzene, and dried to give 6.4 mL of crude crystals of N-p-nitrobenzyl-N'-p-nitrophenyl urea.
8 g (yield: 82%) was obtained.

The crude crystals were recrystallized from 95 ml of a mixed solvent of ethyl alcohol and acetone (volume ratio 1:1), and the crystals were filtered and dried to give a yellow-white mixture of N-p-nitrobenzyl-N'-p-nitrophenyl urea. 5.02 g of lust crystals were obtained.

The melting point of this crystal was 226°C.

The elemental analysis values of this crystal were as follows.

Actual value C, 53, 16%; H, 3, 84%; N, 17
．． Calculated value as 95% C14H12N4O5 C,53,16
%; H, 3.80%; N, 17.72% The infrared absorption spectrum of this crystal is shown in FIG.

Synthesis of N-p-aminobenzyl-N'-p-aminophenyl urea; 3.0 g of crystalline N-p-nitrobenzyl-N'-p-nitrophenyl urea, 160 ml of N,N'-dimethylacetamide and carbon 0.3 g of a catalyst supported with palladium (manufactured by Kouki Fine Chemicals Co., Ltd., palladium-carbon type catalyst, palladium content: 5% by weight) was charged into a titanium-lined, electrode-stirred autoclave with an internal volume of 400 m1, and then Supply hydrogen until the pressure reaches 40Kg/cm2 (absolute pressure), then heat to 90℃ without replenishing hydrogen.
The reduction reaction was carried out for 2 hours.

The catalyst was filtered off from the reaction product mixture, and the filtrate was distilled to give N,
Approximately 130 ml of N-dimethylacetamide was distilled off.

The distillation residue was added to 400 ml of water, and the precipitated crystals were filtered off.

These crystals were dissolved in 80 ml of 35% by weight hydrochloric acid, and 0.5 g of activated carbon was added to this solution and stirred at 70 to 80°C for 1 hour.

The activated carbon was filtered off and the solution was neutralized by adding an aqueous sodium hydroxide solution to precipitate white crystals.

The crystals were filtered under a nitrogen atmosphere and then dried to obtain 1.87 g of fine crystals of N-p-aminobenzyl-N'-p-aminophenyl urea (reduction yield near 7%).

This crystal had no melting point and thermally decomposed at temperatures above 202°C.

The elemental analysis values of this crystal were as follows.

Actual value C, 65,34%; H, 6,27%; N2
1.98% Calculation surface as C14H16N4O C, 65, 63%
; H6, 25%; N, 21.88% The infrared absorption spectrum of this crystal is shown in FIG.

Reference Example (Synthesis of aromatic polyamide using N-p-aminobenzyl-N'-p-aminophenyl urea) 2.45 g of p-phenylenediamine, N-p-aminobenzyl-N'-p-aminophenyl urea 1.50g,
81.3 ml of N-methylpyrrolidone and 40.7 ml of hexamethylphosphoramide were placed in a 500 ml flask and stirred under a nitrogen atmosphere to form a homogeneous solution.

After this time the flask was immersed in an ice bath.

After 20 minutes, 5.95 g of terephthalic acid dichloride was added and stirred for 30 minutes.

The solution became viscous due to polymer formation.

The ice bath was removed and the flask contents were stirred for 2 hours without heating or cooling.

After this, the flask contents were left at 20° C. for 12 hours, and the contents of the flask were added to water and washed with water while being crushed with a mixer.

The filtered polymer was immersed in an aqueous sodium bicarbonate solution for 12 hours, and then the polymer was filtered, washed with water and acetone, and dried.

7.81 g of an ocher-colored polymer was obtained.

The intrinsic viscosity of this polymer (98
(measured at 30°C for wt% sulfuric acid) is 0.78 dl/g
Met.

The heat resistance of this polymer was measured using a differential thermobalance TG- manufactured by Rigaku Denki.
When measured using a DSC standard model at a heating rate of 5°C/min, 2% weight loss was 436°C and 4% weight loss was 447°C.
Met.

[Brief explanation of drawings]

Figures 1 and 2 show N-p-nitrobenzyl-N'-p-nitrophenylurea and N-p-
It is an infrared absorption spectrum of aminobenzyl-N'-p-aminophenyl urea.

Claims (1)

[Claims] 1 N-p-aminobenzyl-N'p-aminophenyl urea represented by the formula. 2 p-Nitrobenzylamine and p-nitrophenyl isocyanate are reacted in an aromatic hydrocarbon at a temperature in the range of 0 to 140°C to produce N-p-nitrobenzyl-N′-p-nitro The first step is to produce phenylurea, and the second step is to reduce the compound represented by formula [■] in an organic solvent selected from amides, aliphatic alcohols, and aliphatic ethers at a temperature in the range of 0 to 140°C. A method for producing N-p-aminobenzyl-N'-p-aminophenyl urea represented by the formula consisting of steps.