JPH01238561A - Production of 1,3-dihydro-4,6-diaminobenzene - Google Patents

Abstract

PURPOSE:To obtain the title compound which is used as a structural material without formation of explosive by-products in no need of dangerous process by allowing 1,3-dihalobenzene to react with nitric acid, then an alkali metal hydroxide and to conduct hydrogenation. CONSTITUTION:1,3-Dihalobenzene which may be substituted with alkyls where the 4,6-positions are not substituted is allowed to react with nitric acid or potassium nitrate in a solvent such as sulfuric acid at 10-90 deg.C to give 1,3-dihalo-4,6- dinitrobenzene. Then, the product is allowed to react with an alkali metal hydroxide under such conditions where the halogens are substituted with hydroxide or its salt, in a medium such as water at 60-130 deg.C to give 1,3-dihydroxy-4,6- dinitrobenzene or its salt. Further the product is reduced with a reagent such as stannous chloride in a medium such as hydrochloric acid at 20-100 deg.C to give the subject compound.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for producing 1,3 dihydroxy 4,6 diaminobenzene.

More specifically, 1.3 does not produce explosive by-products.
The present invention relates to a method for producing dihydroxy 4.6 diaminobenzene.

<Prior Art> It is known that 1.3 dihydroxy 4,6 diaminobenzene reacts with an aromatic dicarzene acid such as terephthalic acid to produce polybenzbisoxazole. (
James F, Wolfe; Macromole
cules.

P915. (1981)) Fibers made of such polymers have high strength, high modulus of elasticity, and excellent heat resistance and chemical resistance, and are expected to be used as next-generation structural materials.

By the way, the conventional method for producing this compound was to acetylate resorcin, nitrate it with nitric acid, and then hydrolyze it, but in the nitration stage, only 30% of the dinitro form was produced. Since most of the residue is the explosive trinitro compound, a dangerous step was required to isolate and purify the desired dinitro compound.

(Typke, Ber, Dtsch, C!hem
, Ges 16. P 551 (1883) and “
The Encyclopedia of Polym
er 5cIens and Englneer1mg
``2nd Ed, J Wtlly & Son (
(1987) ) <Problems to be Solved by the Invention> In view of these drawbacks of the prior art, the present invention eliminates the by-product of trinitro compounds that have conventionally been produced in the manufacturing process of compounds, and therefore eliminates the isolation and purification process. The purpose is to provide a manufacturing method that does not require

A last resort to solving problems The gist of the present invention is as follows.

(,) Unsubstituted or substituted with 5 or 2 alkyl groups, however, for the part 4.6, unsubstituted 1,3 dihalobenzene with nitric acid or potassium nitrate,
(b) contacting it3'/halo4,6 dinitrobenzene with an alkali metal hydroxide in a reaction medium under conditions such that 1,3 dihalo4,6 dinitrobenzene is produced; contacting under conditions such that the moiety is replaced with a hydroxide or a salt thereof,
(c) preparing 1,3 dihydroxy 4,6 dinitrobenzene or a salt thereof in an acidic reaction medium;
6-,) A method for producing 1,3-dihydroxy-4,6-diaminobenzene, which comprises reducing under conditions in which aminobenzene is produced.

The method of the present invention prevents the generation of by-products of 1,3
This results in the production of dihydroxy 4,6 diaminobenzene.

In the first step of the present invention, 1,3 dihalobenzene which is unsubstituted or substituted with 1 to 2 alkyl groups, but is unsubstituted for the 4,6 moiety, is prepared in an acidic reaction medium.
By contacting with nitric acid or potassium nitrate, 1,3 dihalo4
, 6 dinitrobenzene. A suitable starting material is
All 1,3-dihalobenzenes in which the benzene ring is unsubstituted or substituted with 1 to 2 alkyl groups are included, provided that the 4.6 moiety is unsubstituted.

In the present invention, "halo" means chlorine, bromine, iodine and fluorine. Preferred 1.3-) halobenzenes have formula C
Corresponds to I).

In the formula, R is independently hydrogen or an alkyl of ~010, X is independently a halogen, and a is 0
, 1 or 2 integers.

The 1,3 dihalobenzenes useful in the present invention include side-lighting, 1,
2dichloro2methylbenzene, 1,3dichloro2ethylbenzene, 1,3dichloro2propylbenzene, 1,3
Dibromo2methylbenzene, 1.3dibromo2ethylbenzene, 1.3dibromo2propylbenzene, 1,3dichloro5methylbenzene, 1,3dichloro5ethylbenzene, 1,3dichloro5propylbenzene, 1,3dibromo5methylbenzene , 1,3 dibromo5-ethylbenzene, 1. :17Bromo5propylbenzene having no acyl or alkyl substituents is preferred, and 1,3 dichlorobenzene is particularly preferred.

The products produced at this stage are unsubstituted or
1゜3dihalo4,6 which may be substituted with alkyl groups
−j is nitrobenzene. Preferred 1,3 dihalo 4,
6-dinitrobenzene can be exemplified by formula (II).

In the formula, R, X, and m are as defined above.

The 1,3 dihalo 4,6-,l nitrobenzenes useful in the present invention include 1.3 dichloro 2 methyl 4,6 dinitrobenzene%, 1.3 dichloro 2 ethyl 4,6 dinitrobenzene,
1.3 dichloro2propyl 4.6 J) nitrobenzene, 1.3 dibromo2methyl 4.6 dinitrobenzene, 1
．． 3 dibromo 2 ethyl 4,6 dinitrobenzene, 1.3
dibromo2propyl 4.6 dinitrobenzene, 1.3 dichloro5 methyl 4.6 dinitrobenzene, 1.3 dichloro5 ethyl 4,6 dinitrobenzene, 113 dichloro5
Propyl 4.6 Dinitrobenzene, 1,3-)bromo5methyl4.6 Dinitrobenzene, 1,3 dibromo5
Ethyl 4.6 dinitrobenzene, 1.3 dibromo 5 propyl 4.6 dinitrobenzene, especially 1,3 dihalo 4,6 dinitrobenzene having no alkyl group is preferred, 1.3 dichloro 4.6 per % Dinitrobenzene is most preferred.

The method of the first stage can be illustrated by the following formula.

In the formula, I'L, X, and a are as defined in the above constant H.

In the first step, the desired 1,3 dihalo4,6 dinitrobenzene can be produced by known methods. (e.g. GE340831) Generally, 1,
Although about 2 equivalents of nitric acid or potassium nitrate are allowed to react with 3-dihalobenzene, it is preferable to use 2 equivalents of excess nitric acid or potassium nitrate to complete the reaction.

The acidic reaction medium includes sulfuric acid, hydrochloric acid, acetic acid, trifluoroacetic acid, phosphoric acid, methanesulfonic acid, hydro7hydric acid, etc., with sulfuric acid being preferred. Although the present invention can be carried out at any temperature at which the desired product is produced, preferred temperatures are 10-90°C, more preferably 20-80°C for nitric acid.
When using potassium nitrate at 0°C, preferably 10
-160°C, preferably 30-150°C.

The reactants are allowed to react for a sufficient time to produce the desired product. The preferred reaction time is 1 to 48 hours;
It is preferably 2 to 24 hours.

After the reaction is completed, it can be diluted with water, preferably water at 0°C, precipitated, and recovered by filtration.

The yield of 1,3 dihalobenzene at this time is 70-98%
The content is preferably 90 to 98%. It's necessary,
It can be purified by recrystallization with 95% methanol.

In the second step of the present invention, the 7'C1
! +3N Yaguchi 4,6 sinitrobenzene is converted into 1,3 dihydroxy 4, which may be unsubstituted or substituted with one or two alkyl groups, so that the halo moiety replaces the hydroxide component or its salt. .6 contacted with an alkali metal hydroxide in the reaction medium to produce dinitrobenzene.

Preferred 1,3 dihydroxy 4,6 dinitrobenzene or a salt thereof corresponds to formula (to).

In the formula, R and a are as defined above, and z is independently hydrogen or a cation.

1,3 dihydroxy 4,6 dinitrobenzene or a salt thereof useful in the present invention is 1,3 dihydroxy 2 methyl 4,
6 dinitrobenzene, 1.3 dihydroxy 2 ether 4.
6 dinitrobenzene, 1,3 dihydroxy 2 propyl 4
, 6 dinitrobenzene, 1,3 dihydroxy 5 methyl 4
．． 6 dinitrobenzene, 1.3 dihydroxy 5-ethyl 4,6 dinitrobenzene, 1.3 dihydroxy 5-propyl 4,6 dinitrobenzene, or an alkali metal salt thereof. Particularly preferably 1,3 dihydroxy 4°, 6
It is dinitrobenzene.

The method at this stage is generally exemplified by the formula below.

(I[) (2) In the formula, R
, Z and a are as defined above, and M is an alkali metal.

The method for converting 1.3 dihalo 4,6 dinitrobenzene into 1,3 dihydroxy 4,6 dinitrobenzene is a known method (E, Chem, 8. Jg, P 33B
(196B) ) can be used, but the following method is preferred.

That is, 1,3 dihalo 4,6-j nitrobenzene is reacted with at least 2 equivalents of excess alkali metal hydroxide. Preferred alkali metal hydroxides include sodium hydroxide, potassium hydroxide, lithium hydroxide, and most preferably sodium hydroxide.

Although the process can use a sufficient amount of reaction medium to react the reaction components occurring in the reaction medium, the preferred reaction medium is an inert solvent and water, with water being most preferred.

Further, the concentration of the alkali metal hydroxide in the reaction medium at this time is 2 to 40%, preferably 5 to 30%.

This method can be set at any temperature that produces the desired product, preferably from 60 to 130°C, more preferably from 65 to 90°C.

1.3 dihalo4.6 dinitrobenzene is recovered by [1], but it may be used as a solution in the next reduction reaction without being recovered.

In the third step of the invention, 1,3 dihydroxy 4°6 dinitrobenzene is reduced to 1,3 dihydroxy 4,6 diaminobenzene. In the present invention, 1.3 dihydroxy 4.6 diaminobenzene is generally recovered as an amine salt, so it also means an acidic amine salt of 1.3 dihydroxy 4,3 diaminobenzene.

The preferred 1.3 dihydroxy 4.6 diaminobenzene corresponds to Shikijun.

In the formula, 几 and 3 are as defined above.

The 1,3 dihydroxy 4,6 diaminobenzenes useful in the present invention include 1,3 dihydroxy 2 methyl 4,6 diaminobenzene, 1,3 dihydroxy 2 ethyl 4,6 diaminobenzene, 1,3 dihydroxy 72 propyl 4,6 Diaminobenzene, 1.3 dihydroxy 5 methyl 4.6 diaminobenzene, 1,3 dihydroxy 5 ethyl 4,6 diaminobenzene, 1.3 dihydroxy 5 propyl 4.6 diaminobenzene. Particularly preferred is 1,3 dihydroxy 4.6 diaminobenzene.

1.3 dihydroxy 4.6 dinitrobene+;! / to 1
The reduction to ゜3-dihydroxy-4.6-diaminobenzene can be carried out by a known method.

For example, this can be achieved by contacting hydrogen or hydrogen gas with a hydrogenation catalyst such as palladium on carbon in an acidic reaction medium.

Alternatively, it can be produced by reacting a reducing agent such as stannous chloride in an acidic reaction medium such as hydrochloric acid.

The acidic reaction medium includes hydrochloric acid, hydrobromic acid, hydroiodic acid, nitric acid, etc., with hydrochloric acid being particularly preferred.

In the present invention, the 1,3 dihydroxy 4,6 diaminobenzene produced is preferably recovered in the form of an acidic amine salt in an acidic reaction medium.

The reaction temperature may be any temperature condition that produces the desired product, but is preferably 20 to 100°C, more preferably 30 to 90°C.

In this case, the amine salt usually precipitates out of solution and can be recovered by filtration. The product can then be purified by recrystallization.

EXAMPLES The present invention will be explained below with reference to Examples, but the present invention is not limited thereto.

<Example> 1.3 dichlorobenzene, 9x, a dihydroxy 4.
6-77 Method for producing minobenzene hydrochloride (1) 1.3 Method for producing dichlorobenzene In a 500 d flask, 100
Add concentrated sulfuric acid and 20.0122 g of 1,3 dichlorobenzene at room temperature. Further, 60 ml of potassium nitrate solution is added and heated to 130°C. That-! After keeping the reaction mixture at a temperature of 3 hours, the reaction solution was poured onto ice at 0° C. to precipitate the product, which was then filtered.

The obtained product was 30.011 F and the yield was 93%.
Met.

(b) Method for Preparing 1,3 Dihydroxy 4,6 Dinitrobenzene 100 d of 5% strength sodium hydroxide and 4,989 d of 1,3 dichloro 4,6 dinitrobenzene are added to a flask having a 500 ml reflux tube. The solution is heated at reflux under nitrogen for 4 hours. After the reaction is completed, the reaction solution is cooled to room temperature and the product is collected by filtration.

The product obtained had a weight of 3.04 f and a yield of 72%.

(C) Method for producing 1,3 dihydroxy 4.6 diaminobenzene Add 10 portions of methanol to 3,042 portions of 1,3 dihydroxy 4.6 dinitrobenzene in a 500 cell flask. A solution of 1st stannous chloride added to 30 Q we 12-N hydrochloric acid was heated at room temperature (21°C) under a nitrogen atmosphere.
While stirring, slowly add the mixture dropwise over 2 hours.

The product obtained was 2.15r and the yield was 79%.

(d) Recrystallization of 1.3 dihydroxy 4,6-diaminobenzene hydrochloride To 400 l of 6-N hydrochloric acid, add 69 stannous chloride and 22 activated carbon, and pre-purify with nitrogen to give an oxygen is replaced, then 2.15 t of the above reactants are added and heated to 85° C. under nitrogen atmosphere.

After complete dissolution, the solution is filtered under heating and the filtrate is reduced to 0.
Cool to ℃ and recrystallize.

After filtering and washing with acetone, the precipitate is dried at 30° C. under vacuum.

<Effects of the Invention> Compared to conventional methods, the production method of the present invention generates almost no trinitro form, so there is no need for the complicated and dangerous process of isolating and purifying the dinitro form before proceeding to the next step. It has the excellent feature of not having any

Patent applicant: Asahi Kasei Industries, Ltd.

Claims (1)

Scope of Claims: (a) Unsubstituted or substituted with 1 or 2 alkyl groups, provided that for moieties 4 and 6, unsubstituted 1,
(b) 1,3 dihalo 4,6 dinitrobenzene is contacted with nitric acid or potassium nitrate in an acidic reaction medium under conditions that produce 1,3 dihalo 4,6 dinitrobenzene; (b) 1,3 dihalo 4,6 dinitrobenzene is contacted with alkali metal water; contacting the oxide in a reaction medium under conditions such that the halo moiety is replaced with the hydroxide or a salt thereof;
, 3 dihydroxy 4,6 dinitrobenzene or a salt thereof; and (c) 1,3 dihydroxy 4,6 dinitrobenzene or a salt thereof in an acidic reaction medium.
A method for producing 1,3-dihydroxy 4,6-diaminobenzene, which comprises reducing under conditions in which 6-diaminobenzene is produced.