DE1768917A1 - Process for the preparation of aromatic dicarboxylic acid diazides - Google Patents

Description

Troisdorf, July 10, 1968 68 097 (H55)

DYNAMIT NOBEL AKTIENGESELLSCHAFT Troisdorf, District Cologne

"Process for the preparation of aromatic dicarboxylic acid diazides"

The present invention is a method for Production of aromatic Diearbönsäurediaziden the general formula

can be 0 to 4 wherein R = one or more organic substituents, and η, which is characterized in that a solution of a corresponding dicarboxylic acid dichloride with a 10-40 '^ term solution of a Älkalifizldö at temperatures between ⁰ C and 30 ⁰ C ₁ preferably between 10 ⁰ C and 20 ° C. The acid azides obtained by this process are obtained in a particularly pure form, such as are necessary, for example, for polycondensation.

109853/1804

In general, acid azides are prepared by reacting the corresponding acid hydrazides with aqueous nitrous acid.

It is also known to react acid chlorides of aliphatic monocarboxylic acids with sodium azide. However, this method is preferably carried out under anhydrous conditions worked and it is mainly only suitable for very reactive acid chlorides such as acetyl chloride.

However, these known methods are poorly suited to dicarboxylic acid diazides, especially tere- and isophthalydiazide in to represent such a pure Porm that they are suitable for polycondensation reactions} The functionality of the reactive azide grouping is not always full in the case of the carboxylic acid azides prepared by these known processes obtain.

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According to the invention, however, the aforementioned dicarbon

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eäurediazide in a simple manner in such a purity, that the azide grouping is fully retained and no disintegration

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decomposition to leobyanate or more extensive decomposition

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'dukes appearance.

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According to the invention, the starting materials for daa are new

Process acid chlorides with a benzene nucleus and two acid chloride groups in any position to one another

109853/18 (U

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used, such as phthalyl chloride and its Homologues. However, the products substituted on the benzene nucleus of these acid chlorides are also suitable. As a substituent may be mentioned, for example: alkyl, aryl and aralkyl radicals, cyclic radicals, halogen. The aryl radicals can also do so be connected to the benzene nucleus that they have two carbon atoms in common with the benzene nucleus, e.g. for 1,4-naphthoyl dichloride.

The dicarboxylic acid diazides produced by the new process are explosive. They react especially when dry to friction, impact or strong and rapid heating with violent detonation. This sensitivity to detonation, on the other hand, decreases sharply in the moist, particularly water-moist, state, so that it can be handled well in this state if normal precautionary measures are observed. Because of this sensitivity to detonation, the procedure for preparing these dicarboxylic acid diazides is generally as follows: Sodium azide is dissolved in water until it is saturated, the solution being slightly warmed. To diener after cooling to about 20 ⁰ C the filtered solution is allowed under vigorous stirring and cooling a solution of the acid chloride in an organic solvent is added dropwise, with the temperature not exceeding 25 ⁰ C as possible. After the exothermic reaction has ended, the mixture is diluted

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with plenty of water, the organic phase which may be formed is separated off and the acid azide which has separated out is filtered off and slurried it in water several times.

The work-up of the acid azides prepared according to the invention must therefore be carried out with the necessary care. It is

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It is easily possible to suck it off sharply when it is damp with water and then ^to dry it in a vacuum at room temperature over a strong desiccant such as Po ^ R. When dry, however, they should no longer come into contact with metal, but should be stored briefly in plastic containers and only touched with objects made of plastic or horn. It is much more advantageous to continue to use the dicarboxylic acid diazides formed in solution; Any water that may interfere with this can be removed using a drying agent, expediently a molecular sieve.

The optimal temperature range of the reaction is between 0 ° C and * 2O ⁰ C. The reaction proceeds at low temperatures very slowly and in poor yield. Exceeding 25 ^° C. should be avoided as far as possible because above this temperature partial decomposition to the isocyanate occurs.

All water-soluble alkali azides are suitable for the implementation and optionally also the alkaline earth azides, provided they are readily soluble in water. Sodium azide is advantageous

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1098S3 / 1804

used. It is beneficial to use an excess of alkali azide to work, an excess of 20 50 mol #, based on the acid chloride, is advantageous.

As a solvent for-the alkali acid is mainly suitable Water. However, it is also possible to use the alkali azide in a water-miscible solvent, such as e.g. acetone or lower aliphatic alcohols to dissolve, and to carry out the reaction in these solvents » Mixtures of these solvents can also be used.

The preferred solvents for the acid chlorides are solvents that are miscible with water, such as alcohols, acetone and dioxane. But it is also possible to work in water-immiscible solvents such as chloroform, ether and petroleum ether, if vigorous stirring is carried out during the reaction. When using these solvents can remain the resulting acid azide after reaction in solution and must by freezing, precipitation or careful evaporation in vacuo, with temperatures are from about 3O ⁰ C must be avoided, can be obtained.

The analytical identification of the resulting dicarboxylic acid diazides is difficult. The elemental analytical combustion is subject to certain precautionary measures possible, but the results can vary widely.

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Melting point determinations are only possible if the decomposition point is higher than the melting point. The exact determination of the decomposition point is usually not reproducible. The most secure identification remains the IRr

Spectrum in solution} there are characteristic outcomes

-1 -1 . Bororption bands between 2100 cm and 2200 cm. Often , however, it is also possible to characterize the diacid diazides formed by their reactions

The acid azides produced according to the invention can be used as blowing agents and crosslinkers for plastics and as insecticides.

example 1

78 g (1.2 Hol) sodium azide was dissolved in 200 ml water and filtered. In this solution was in the thermostat at + 20 ⁰ O with vigorous stirring 101.5 g of terephthalic

^% phthalyl chloride in 300 ml of acetone added dropwise · An then 200 ml of water were added, the liquid was decanted off from precipitating terephthalic acid and stirred up several times with plenty of water and washed · Am part was in the Vacuuroexsiccätor over Dried phosphorus pentoxide.

The product melts at 110 ⁰ O, after one recrystallization at 115 ⁰ O-116 ⁰ O. It detonates at

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Effects of friction and impact and when heated above the melting point. In the IR spectrum shows it has the characteristic absorptions between 2100 cm and 2200 cm.

Example 2

78 g (1.2 mol) of sodium azide were dissolved in 200 ml of water with heating, filtered, cooled to 2O ⁰ C and a solution of 101.5 g (0.5 mole) of isophthalyl chloride in 300 ml of acetone. Work-up was carried out as indicated in Example 1.

The product melts at 65 ° C - 66 ⁰ C, after a single recrystallization from acetone at 71 ⁰ C. It is still more sensitive than Terephthalylazid and also shows in the IR spectrum absorption at 2100 cm "* ^1-2200 cm ^'1.

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Claims (2)

Claims 1. Process for the production of aromatic dicarbon acid diazides of the general formula can be 0 to 4 wherein R = one or more organic substituents, and η, characterized in that einee a solution of a corresponding dicarboxylic acid dichlorides with a 10 to 40 #igen alkali metal azide solution at temperatures between 0 C and 30 ⁰ C, preferably between 10 C and 20 C. 2. The method according to claim 1, characterized in that the solvent for the dicarboxylic acid dichloride a water-miscible solvent is used. 3. Method according to claim 1 and 2, characterized in that that the solvent for the alkali azide is water and / or a water-miscible solvent is used Dr.Sk/Ko 109853/180