JPS59199657A - Method for removing o-phenylenediamine from phenylenediamines - Google Patents

Abstract

PURPOSE:To remove o-phenylenediamine from phenylenediamines containing o- phenylenediamine, easily and efficiently, by reacting the diamines with a specific compound. CONSTITUTION:Phenylenediamines (e.g. p-phenylenediamine) containing o-phenylenediamine are heat-treated at 100-270 deg.C in the presence of furfural, furfural and an acid, or an adduct of furfural and a bisulfite, and the heat-treated product is distilled. As an alternative process, the diamines are distilled at 100- 270 deg. in the presence of furfural, etc. to effect the removal of o-phenylenediamine from the aromatic diamines. The m- and p- phenylenediamines having extremely low o-phenylenediamine content or absolutely free from the diamine are useful as a raw material of heat-resistant polyamide.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for removing orthophenylenediamine from phenylenediamines. More specifically, furfural or a bisulfite additive of furfural and an acid or furfural is added to phenylene diamines containing ortho-phenylene diamine, and the ortho-phenylene diamine and the additive are heated to react, thereby producing ortho-phenylene diamine with a high boiling point. This invention relates to a method for removing or-1-phenylenediamine from phenylenediamines, which comprises distillation after conversion into a product.

Meta- and para-phenylenediamines have been used in large quantities in the Komu Pharmaceutical Industry and the dye and pigment industry for a long time.
Recently, it has been used industrially as a raw material for heat-resistant polyamide.

Usually, meta-phenylene diamine is produced by reduction of metadinitrobenzene, and para-phenylene diamine is produced by reduction of varanitroaniline or para-aminoazobenzene, or meta- and para-phenylene diamines produced by such methods are usually Ortho-phenylecidiamine or about 1 to 10:! , present as an impurity in an amount of about %.

Conventionally, methods for removing ortho-phenylene diamine from meta- and O-para-phenylene diamines containing gold include the use of glucose or glyoxal or its A method of separating orthoaromatic diamines by distillation with the addition of a bisulfite adduct, and a method of separating orthoaromatic diamines by distillation with the addition of a bisulfite adduct, and a method of separating orthoaromatic diamines by adding formamide or porumamido mavic acid and heating treatment, as shown in Japanese Patent Publication No. 57-7624, Methods of distilling and separating orthoaromatic diamines are known.

However, in these methods, it is difficult to directly add glyoxal and formamide during the distillation operation because the boiling point of glyoxal and formamide is lower than the melting point of phenylene diamines in a normal pressure system or a reduced pressure system, and it is difficult to carry out the direct addition treatment during the distillation operation. This method has the inconvenience of requiring pretreatment of the pressurized yarn and the inconvenience of having to use multiple reagents to obtain a sufficient effect.

The inventors of the present invention have conducted intensive studies to overcome the shortcomings of these conventional methods and to obtain meta- and para-phenylene diamines containing very little to no ortho-phenylene diamine in a simpler and more efficient manner. As a result of this research, the inventors discovered that highly pure phenylene diamines can be obtained when ortho-phenylene diamine is reacted with a specific compound and distilled, and the present invention has been achieved.

That is, the present invention involves heat-treating orthophenylenediamine containing t-phenylenediamines in the presence of furfural or furfural and an acid or a bisulfite adduct of furfural at about 100 to 270°C and then steaming or It is an object of the present invention to provide a method for efficiently removing phenylene diamines containing orthophenylene diamine by distillation at a temperature of 100 to 270C.

In carrying out the method of the present invention, the phenylene diamines containing ortho-phenylene diamine used as the treatment target are not particularly limited, but are usually meta-phenylene diamine produced by reduction of meta-dinitrobenzene17 or para-aminoiso For the reduction of benzene and the ammonia of chloroaniline, p-phenylenediamine produced by sulfur ammonolysis, reduction of nitroaniline, amination of the hydroxyl group of aminophenol with ammonia, ammonolysis of dichlorohenzene with ammonia, etc. is preferably used.

Generally, the phenylenecyamines produced by these methods contain about 10% by weight or less of ortho-hydrogen.

In carrying out the process of the present invention, furfural or a bisulfite adduct of furfural and acid or furfural is added to the phenylenecyamines to react with the orthophenylenediamine present in the phenylenecyamines.

Acids used in combination with furfural include sulfuric acid, hydrochloric acid, benzenesulfonic acid, toluenesulfonic acid, acetic acid,
Benzoic acid is cooled down.

The amount of furfural added is determined by the amount of ortho-phenylene diamine contained in the phenylenecyamines, and the molar ratio of furfural to ortho-phenylene diamine, which is usually quenched, is 1 or more, preferably 1.
It is used in the range of 05 to 4.

If the molar ratio of furfural to ortho-phenylenediamine is less than 1, the removal rate of or-1-phenylenediamine will decrease, while if it is in excess of 4, unreacted furfural will need to be treated, which is not desirable industrially.

When carrying out the method of the present invention, is it possible to remove orthophenylenediamine by adding only furfural to phenylenediamines containing orthophenylenecyamine and heat treatment? If carried out in the presence of acetic acid, the reaction between ortho-phenylenediamine and furfural will be significantly improved, and the target to-ortho-phenylenediamine can be removed by heat treatment at a lower temperature and in a shorter time, making it an extremely excellent method from an industrial perspective.

Generally, the amount of acid added is 0.00 molar ratio to ortho-phenylene diamine present in phenylene diamines.
It is used in a ratio of 1 or more, preferably 0.3 to 2.

Furthermore, the sulfites used in the present invention may include sodium salts, ammonium salts, etc. of sulfites.

Additives of furfural and bisulfite can be easily produced by mixing furfural and bisulfite, or the same effect can be obtained by adding furfural and bisulfite separately to phenylene diamines. can be obtained.

The amount of the monosulfite adduct of furfural to be added is desirably in a molar ratio of 1 to 10, preferably about 1.05 to 4, relative to the normally contained orthophenylene diamine.

When the molar ratio of the bisulfite adduct of 1 to 1 is less than 1, the removal of ortho-phenylenediamine decreases, while when the molar ratio is more than 4, it is necessary to treat the bisulfite adduct of unreacted furfural. Industrially undesirable.

In carrying out the method of the present invention, a mixture of phenylenediamines containing ortho-1-phenylenediamine and the above additives is used to react the orthophenylenediamine and the additive to convert the orthophenylenediamine into a high boiling point product. heated.

The temperature when furfural and acid or bisulfite adducts of furfural are added to phenylene diamines and heated or heated under heat treatment conditions varies depending on the amount and type of additive, and generally the temperature is 2
At temperatures above 70°C, the decomposition and cooling of phenylenediamines are accelerated, resulting in a significant decrease in the yield of meta- and para-phenylenediamines, while at temperatures lower than 100°C, removal of ortho-phenylenediamines is accelerated. The temperature is usually between 100 and 270 degrees Celsius.
and processed.

The heat treatment time is not particularly limited, but usually several seconds to about 60 minutes is sufficient. There is no particular problem even if the heat treatment time is made longer.

The phenylene diamines heat-treated as described above are then subjected to a distillation treatment to separate and recover the desired phenylene diamine that does not contain the ortho form. The distillation temperature can be arbitrarily selected depending on the operating pressure.

In the above explanation, we have explained the case where additives are added to phenylene diamines, heat treated, and then distilled.
In the method of the present invention, this heat treatment and distillation can be carried out simultaneously, which is a particularly preferred embodiment. In such embodiments, the distillation is conducted at about 100-270<0>C. The reason is the same as the heat treatment conditions.

In this way, the content of the ortho isomer in the phenylenediamine fraction obtained by distillation can be made to be less than 1.0%, preferably less than 1.0%, and this can be achieved in an industrial manner. The value is extremely high.

According to the method of the present invention as described in detail above, compared to conventionally known methods, a small amount of additives can be used to produce methane containing less orthophenylenediamine (1) or no methane at all. Alternatively, the industrial advantage of being able to obtain para-phenylenediamine can be demonstrated. Furthermore, the method of the present invention has the advantage of practical simplicity in that it does not require a pressurized reaction unlike conventional methods.

The present invention will be explained in more detail below with reference to Examples, but the present invention is not limited by these Examples. In addition, the rate of missing examples is 11, which is 10%.

Example 1 2.8 q of orthophenylenediamine and 2.3 q
Para-phenylene diamine 307 containing aniline of 6
1 was placed in a 500 cc round-bottomed flask, and after completely melting at a temperature of 165 to 180°C while introducing nitrogen gas through a capillary, the furfural tofu x-,':'-1/diamine was 2.
5 times molar equivalent) and 50 ammonium bisulfite aqueous solution 1 4. 1! 7- were sequentially added to the pot solution, and total reflux was performed for 30 minutes. Next, simple distillation was carried out at a vacuum pot temperature of 160 to 180°C under a reduced pressure of 30 to 60wπHg-, and after removing the first distillate 315' containing aniline, water, furfural, etc., the distillate 25 was mainly composed of p-phenylenediamine.
I got 2z.

The concentration of orthophenylenediamine in the paraphenylenecyamine fraction was 0.05%.

On the other hand, for comparison, a sample was treated in exactly the same manner as above except that the 50% ammonium bisulfite aqueous solution was not added. - As a result, the concentration of orthophenylenediamine in the obtained bulk phenylenecyamine fraction was 2.4%.

Example 2 Paraphenylenediamine 80 with the same composition as Example 1
0.07 was charged into the same container used in Example 1 and completely dissolved in the same manner, and then furfural was added to 29.0.
8 5' (4 for orthophenylenediamine)
0 times molar equivalent) was added to the pot liquid, and total reflux was carried out for 90 minutes. Next, simple distillation of 30-6 Q yLyzHy- was carried out under reduced pressure to obtain a product containing aniline, furfural, etc.
First distillate 24g- followed by paraphenylenecyamine fraction 2
585' was obtained. The concentration of ol-1-phenylenediamine in the para-phenylenediamine fraction was 0.45%.

Example 3 5 0 0 C. 4.6 liters of oil 1 in round bottom flask C
Para-phenylene diamine 8201 containing phenylene diamine 17.8%, furfural 28.7!74 (2.2 times the molar equivalent to orthophenylene diamine), ammonium sulfite 9 and ammonium hydrogen sulfite 34 Water bath liquid 35 which is the combination of
．． After adding 61, heat under reduced pressure while introducing nitrogen gas from a capillary, and after the whole is completely dissolved, simple distillation is carried out under reduced pressure at a pot temperature of 160 to 190 ° C. and 30 to 45 ml of water. 88g of first distillate containing furfural etc.
51 whose main component is paraphenylenediamine after removing
Obtained 27 By minutes. The concentration of orthophenylenecyamine in the paraphenylenediamine fraction was 0.9%, and the concentration of metaphenylenecyahene was 16.3%.

Examples 4-9 Paraphenylenediamine 3501 with the same composition as Example 1
was charged into the same equipment used in Example 1 and completely dissolved in the same manner, then furfural omahyic acid was added in the proportion shown in Table 1, and after 40 minutes of total reflux, 30 to 60 m
Simple distillation was carried out at a reduced pressure of Hz and a lower pot temperature of 160 to 180°C.
After removing the initial fractions 35 to 402, a fraction containing p-phenylenediamine as a main component was obtained. Table 1 shows the results of analysis of the concentrations of ol-1 to phenylenediamine in the bulk phenylenediamine.

Claims (1)

[Claims] (]) Aromatic diamines containing orthophenylenediamine are added to about 100% of the aromatic diamine in the presence of furfural or furfural and an acid or a bisulfite adduct of furfural.
Heat treatment at ~270°C followed by distillation or removal of about 1007 enylenediamine.