GB2032421A

GB2032421A - Stabilised Percarboxylic Acids

Info

Publication number: GB2032421A
Application number: GB7928997A
Authority: GB
Original assignee: Henkel AG and Co KGaA; Degussa GmbH; Deutsche Gold und Silber Scheideanstalt
Current assignee: Henkel AG and Co KGaA; Evonik Operations GmbH
Priority date: 1978-10-25
Filing date: 1979-08-21
Publication date: 1980-05-08
Also published as: JPS6243990B2; FR2446816A1; ATA526279A; BE878199A; NL7906196A; AT370411B; FR2446816B1; JPS5589263A; DE2930546C2; DE2930546A1; GB2032421B

Abstract

A process for the production of a storage stable desensitized aliphatic and/or aromatic percarboxylic acid, comprises reacting at least one aliphatic and/or aromatic carboxylic acid with hydrogen peroxide in the presence of sulphuric acid, and adding to the reaction mixture at least one substance which reacts with sulphuric acid to form a sulphate salt as a desensitizing agent. The substance which reacts with sulphuric acid is preferably sodium hydroxide, magnesium hydroxide or sodium aluminate. The carboxylic acid used is preferably azelaic acid, adipic acid, suberic acid, sebacic acid, 1,12- dodecandioic acid, benzoic acid, isophthalic acid or mellitic acid.

Description

SPECIFICATION Stabilised Percarboxylic Acids The present invention relates to the production of desensitized and storage stable percarboxylic acids, for example, diperalkanedioic acids.

Solid, water-insoluble peroxy carboxylic acids are thermally and mechanically sensitive when in a pure or highly concentrated form. Various methods for safely handling these compounds are described in the literature (D. Swern: Organic Peroxides, Vol. I-Ill, 1 970-72; R. Griegee in Houben-Weyl, Vol.

8). In some cases, desensitisation may also be obtained by the addition of alkali metal, alkaline-earth metal and ammonium salts of strong mineral acids, such as sulphuric acid.

In this connection, attempts had already been made to further reduce the tendency towards decomposition or spontaneous degradation by using salts poor in water of hydration so that the peroxy carboxylic acids were able to absorb moisture (Belgian Patent No. 560,389).

Converseiy, it had already been proposed to reduce the tendency towards decomposition by using those of the above-mentioned salts which formed the hydrates and which were added in their hydrate form (German Patent No. 1,468,847).

The processes according to German Auslegeschrift No.1,668,569 and German Patent No.

1,668,570 were based on the idea of introducing peroxycarboxylic acids dispersed in water into a fluidised bed of a salt hydrate. In this way, the particles of the percarboxylic acids were supposed to become coated with a shell of the hydrate, although the hydrates had to satisfy strict requirements in regard to the temperatures at which the water of crystallisation could be released, i.e. only very special hydrates could be used.

The shells formed in this way, however, were not continuous, quite apart from the fact that the processes were very expensive and the mixtures tended to cake.

Accordingly, a change was recently made back to the principle of simply mixing the dry or watermoist acid with the dry salts. A certain degree of desensitisation could only, however, be obtained providing the mixture was homogeneous and diluted.

In processes such as these, which are described for example, in Canadian Patent No. 635,620, German Offenlegungsschrift No. 2,442,691 and German Offenlegungsschrift No. 2,442,735, the desensitising agent is subsequently added, giving rise to the danger of partial inhomogeneity. Another disadvantage is that the dry mixing of a highly concentrated peroxy acid with the desensitising agent can in some cases result in greater mechanical sensitivity produced by shearing effects on the edges of the crystals.

It has now been found that the disadvantage of the prior art procedures may be avoided and a storage stable, desensitized product obtained if the desensitizing agent is produced in situ in the reaction mixture.

Thus, the present invention relates to a process for the production of a storage stable, desensitized aliphatic and/or aromatic percarboxylic acid, said process comprising reacting at least one aliphatic and/or aromatic carboxylic acid with hydrogen peroxide the presence of sulphuric acid, and adding to the reaction mixture at least one substance which reacts with sulphuric acid to form a sulphate salt as a desensitizing agent.

Using the process of the present invention, not only is a really homogeneous mixture of the peroxy carboxylic acid and the desensitising agent formed, but also the particles of the peroxy carboxylic acid are completely coated so that, even in the event of damage to a particle, the propagation or decomposition is impossible.

In addition, by virtue of the in situ formation of the desensitising agent, the mineral acid present is immediately co-utilised for desensitising the peroxycarboxylic acid formed. The process according to the present invention overcomes the difficulties hitherto encountered using the dilute aqueous mineral acid (accumulating after the production of the peroxycarboxylic acid and its separation from the reaction mixture) which either had to be worked up or discarded which in turn gave rise to pollution problems.

In one embodiment, the aliphatic carboxylic acid is used is an alkanedioic acid having at least 5, preferably from 6 to 1 6, and more preferably from 6 to 12 carbon atoms.

In another embodiment, the aromatic carboxylic acid used corresponds to the following general formula:

wherein X represents from 0 to 5 substituents which may be the same or different, and which may be a COOH group, A C 1-4 alkyl group, a C14 alkoxy group and/or a halogen atom.

Reference is made above all to benzoic acid, phthalic acids, particularly isophthalic acid and benzene tri- and poly-carboxylic acids, such as mellitic acid. The aromatic carboxylic acid used is preferably dibasic.

In one embodiment, the substance which reacts with sulphuric acid to produce a sulphate salt is an alkali metal hydroxide, an alkaline earth metal hydroxide or sodium aluminate, and is added in such an amount that the pH value of the reaction mixture rises to 2-6. The substance may be added in the form of an aqueous solution or suspension.

Suitable desensitizing agents include alkali metal sulphates, alkalimetalaiuminium sulphates and alkaline earth metal sulphates, preferably Na2SO4, MgSO4 and sodiumaluminiumsulphate or mixtures thereof. Potassium sulphate, calcium sulphate and lithium sulphate may also, however, be used.

The desensitizing agent may be formed in situ by adding sodium hydroxide, magnesium hydroxide, calcium hydroxide, lithium hydroxide, potassium hydroxide or sodium aluminate, e.g. as a 5 to 50% aqueous solution or suspension, to the reaction mixture of the carboxylic acid, hydrogen peroxide and sulphuric acid at a temperature which is usually 0-300C, preferably 1 5-200C, more preferably 1 8-200C until a pH of 2-6, preferably 3-5.5 more preferably 5-5.5 is obtained. There is obtained a homogeneous mixture of percarboxylic acid particles coated with (i.e. encased in) the inorganic salt formed. Mixtures of desensitizing agents can be formed in situ, e.g. using a mixture of sodium and magnesium hydroxides.It is particularly preferred to use an aqueous solution of sodium hydroxide, and aqueous slurry of magnesium hydroxide or an aqueous solution of sodium aluminate.

The reaction between the carboxylic acid and the hydrogen peroxide in sulphuric acid can take place in a conventional manner. The hydrogen peroxide is normally used in excess. Thus there can be used, for example, from 2 to 20 moles of hydrogen peroxide per mole of carboxylic acid. The concentration of the carboxylic acid is not critical. For example, there can be used from 10 to 300 parts by weight of carboxylic acid per 100 parts by weight of sulphuric acid, calculated as 100% H2SO4 by weight.

The concentration of the hydrogen peroxide is not critical and it can be used in a conventional concentration, e.g. from 30 to 99%.

Also, the exact concentration of the sulphuric acid is not critical although it is normally concentrated. (It will be noted that the aqueous hdyrogen peroxide has a diluting effect.) It can be used in a conventional concentration, e.g. from 20 to 90% by weight.

It is preferred to use an alkanedioic acid in the process of the present invention. Suitable alkanedioic acids are, for example glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,1 0-decane dicarboxylic acid, 1,1 2-dodecandicarboxylic acid and 1,14tetradecanedicarboxylic acid.

The two effects of the process of the present invention, the dilution and the coating, besides creating good stability in storage also greatly reduce the thermal and mechanical sensitivity. An advantage of the process of the present invention is that no sulphuric acid is obtained in the filtrate after the separation. For that reason, no pollution problems raise.

In one embodiment of the process of the present invention, the process comprises the additional steps of removing and drying the precipitated peroxy acid coated with the sulphonate salt as a desensitizing agent.

The desensitizing method of the present invention described above was tested using diperoxyadipic acid, diperoxysuberic acid and diperoxyazelaic acid whereby outstanding results were obtained. Examples of the storage stability of diperoxyazelaic when different concentrations of diperoxyazelaic acid are used are shown in the following table.

Table I Weight % Weight % peroxy acid peroxy acid % Decomposition Todays 14 days In 14 days 26.5 26.2 1.3 34.6 34.2 1.2 47.7 47.3 1.0 85.4 84.4 1.2 The mechanical sensitivity was measured by falling hammer tests according to the known method of the "Bundesanstalt fur Materialprufung (BAM) (Federal Institute for Testing Material). For this purpose, some of the samples of desensitized diperoxyazelaic acid were air dried and some were dried in a vacuum at 40-500C over a conventional drying agent. In no case in the complete removal of the residual water was there noted an increase in the sensitivity of the sample.

The influence of the coating of the peroxyacid particles by the desensitizing agent is shown by a comparison of the maximum impact energy obtained in the falling chamber test, which is a measure of the mechanical sensitivity of the samples prepared, using two samples of 85 weight % diperoxyazelaic acid. Sample A was not desensitized and was made according to the method of Parker, J. Amer. Chem.

Soc. Coi. 79, pages 1929-1931(1957) and Swern, J. Amer. Chem. Soc. Vol. 77 pages 5537- 5541, while Sample B was synthesized using the process of the present invention.

Table 2 Maximum Impact Energy (mkg) 85% A 0.7 85% B 2.0 45% C 0.7 As a comparison, there is given the value for a 45% diperoxyazelaic acid (C). This composition C was obtained by dry mixing 92 weight % diperoxyazelaic acid with sodium dry sodium sulphate. The treatment with the desensitizing agent can take place batchwise or continuously.

Unless otherwise indicated, all the parts and percentages quoted represent parts by weight and percentages by weight, respectively.

The present invention is illustrated by the following Examples.

Example 1 A cooled mixture of 743 grams of hydrogen peroxide (50%) and 561 grams of concentrated (95%) sulphuric acid were treated within 1 5 minutes with 414 grams of solid, pulverized azelaic acid and stirred for 20 hours at room temperature. The sulphuric acid reaction mixture thus obtained was subsequently treated with the calculated amount of a 30% aqueous sodium hydroxide solution to give an encased, precipitated diperoxyazelaic acid, which was filtered. After drying the filter residue there were obtained 508 grams of diperoxyazelaic acid desensitized with Na2SO4. The analysis showed a peroxyacid content of 85% by weight and a residual water content of 3% by weight.

Example 2 The reaction mixture produced in accordance with Example 1 from 565 grams of pulverized azelaic acid,1020 grams of 50% aqueous hydrogen peroxide and 81 7 grams of concentrated (95%) sulphuric acid was treated with 35% aqueous Mg(OH)2 slurry until a pH value of 5.0 was obtained. The temperature was maintained at 18--200C. Filtering and drying the product to a constant weight gave 34.6% by weight of diperoxyazelaic acid, desensitized with MgS04. The residual water content was 1% by weight.

Example 3 To a reaction mixture produced according to Example 1 from 226 grams of pulverized azelaic acid, 410 grams of 50% aqueous H202 and 326 grams of concentrated (95%) H2SO4, there were added 796 grams of 30% aqueous NaOH solution with stirring. The pH of the final mixture was 5.2. Filtering and drying in a vacuum to a constant weight resulted in a Na2SO4 desensitized diperoxyazelaic acid.

The peroxyacid content was 26.5% by weight and the residual water content was less than 1% by weight.

Example 4 50 grams (0.34 moles) of adipic acid were dissolved in 40 ml concentrated sulphuric acid. This solution was added to a cooled mixture of 80 ml concentrated sulphuric acid and 93.1 grams (1.37 moles) 50% aqueous hydrogen peroxide. The temperature of the reaction mixture increased to 450C.

Stirring was continued for an additional 1 5 min.

After the addition of 50 ml water, the reaction mixture was treated with an aqueous slurry of Mg(OH)2 until it had a pH-value of 4. The solids were separated by filtration and dried. The yield was 165 grams of diperoxyadipic acid, desensitized with MgS04 (content of peroxyacid: 20.0%).

Example 5 As described in Example 4 50 grams (0.22 moles) of 1.12-dodecanoic acid was mixed with 59 grams (0.87 moles) of 50% aqueous hydrogen peroxide in 120 ml concentrated sulphuric acid. After 1 5 minutes, the reaction mixture was cooled and treated with an aqueous solution of sodium aluminate, produced by mixing 200 grams of Al(OH)3,305 grams of 50% aqueous NaOH and 600 ml of water. After a pH-value of 3.7 was obtained, the solids were separated by filtration. After drying the filter cake, 124 grams of diperoxydodecanoic acid, desensitized with sodiumaluminium sulphate were obtained. The content of peroxyacid was 34.9%.

Example 6 As described in Example 4, 50 grams (0.27 moles) of azelaic acid were treated with 72.3 grams (1.06 moles) of 50% aqueous hydrogen peroxide in 70 ml of concentrated sulphuric acid. After the addition of 1 70 grams of an aqueous solution of MgSO4, the reaction mixture was cooled and treated with an aqueous solution of Mg(OH)2 until it had a pH-value of 3. The solids were separated by filtration, and after drying, there were obtained 99.5 grams of diperoxyazelaic acid, desensitized with MgSO4. The content of peroxyacid was 39.2%.

Example 7 The sulphuric acid reaction mixture obtained from the reaction of 99.7 g of i-phthalic acid (0.6 mole) with 120 g of 85% by weight hydrogen peroxide (3.0 moles) and 306 g of 96% by weight sulphuric acid (3.0 moles) is cooled to 50C and 30% by weight aqueous NaOH is added with continuous stirring until a pH value of 4 is obtained. After filtration and drying, 376 g of product having a DPIP-content of 21.1% by weight are obtained, corresponding to a yield of 66.7% of the theoretical yield.

Example 8 700 ml. of saturated sulphuric acid solution are added to the sulphuric acid reaction mixture obtained from the reaction of 99.7 of i-phthalic acid (0.6 mole) with 96 g of 85% by weight hydrogen peroxide (2.4 moles) and 245 g of 96% by weight sulphuric acid (2.4 moles), followed by cooling to 50C. 30% by weight NaOH is then added until a pH value of 4 is reached. After filtration and drying, 333 g of product having a DPlP content of 22.9% by weight are obtained, corresponding to a yield of 59.2% of the theoretical yield.

Example 9 As in Example 7, 30% by weight aqueous NaOH is added to the sulphuric acid reaction mixture obtained in accordance with Example 7 until a pH value of 5 is reached, followed by working up in the same way as described in Example 7. 423 g of product having a DPIP content of 18.0% by weight are obtained, corresponding to a yield of 64.0% of the theoretical yield.

Example 10 As in Example 7, 309/0 by weight aqueous Li0H suspension is added to the sulphuric acid reaction mixture until a pH value of 5 is reached, followed by working up as described in Example 7. 271.3 g of product having a DPIP content of 33.9% by weight are obtained, corresponding to a yield of 77.4% of the theoretical yield.

Example 11 As described in Example 7, 30% by weight aqueous Mg(OH)2-suspension is added to the sulphuric acid reaction mixture until a pH value of 4 is reached, followed by working up in the same way as described in Example 7. 202.8 g of product having a DPIP-content of 20.9% by weight are obtained, corresponding to a yield of 71.3% of the theoretical yield.

Example 12 As described in Example 7, 30% by weight sodium aluminate suspension is added to the sulphuric acid reaction mixture until a pH value of 4 is reached, followed by working up as described in Example 7. 476 g of product having a DPIP content of 21.8% by weight are obtained, corresponding to a yield of 87.3% of the theoretical yield.

Claims

1. A process for the production of a storage stable, desensitized aliphatic and/or aromatic percarboxylic acid, said process comprising reacting at least one aliphatic and/or aromatic carboxylic acid with hydrogen peroxide in the presence of sulphuric acid, and adding to the reaction mixture at least one substance which reacts with sulphuric acid to form a sulphate salt as a desensitizing agent.

2. A process as claimed in claim 1 wherein the aliphatic carboxylic acid is an alkanedioic acid having at least five carbon atoms.

3. A process as claimed in claim 2 wherein the alkanedioic acid is azelaic acid.

4. A process as claimed in claim 2 wherein the alkanedioic acid is adipic acid, suberic acid, sebacic acid or 1,12-dodecanedioic acid.

5. A process as claimed in claim 1 wherein the aromatic carboxylic acid corresponds to the following general formula:-

wherein X represents from 0 to 5 substituents which may be the same or different and which may be a COOH group, a C14 alkyl group, a C14 alkoxy group and/or a halogen atom.

6. A process as claimed in claim 5 wherein the aromatic carboxylic acid is benzoic acid, isophthalic acid, or mellitic acid.

7. A process as claimed in any of claims 1 to 6 wherein the substance added is an alkali metal hydroxide, an alkaline earth metal hydroxide or sodium aluminate and is added in such an amount that the pH value of the reaction mixture rises to 2-6.

8. A process as claimed in any of claims 1 to 7 wherein the substance added is sodium hydroxide, magnesium hydroxide or sodium aluminate.

9. A process as claimed in any of claims 1 to 8 wherein the substance is added until the pH value of the reaction mixture rises to 3-5.5.

1 0. A process as claimed in any of claims 1 to 9 wherein the substance which reacts with sulphuric acid to produce a sulphate salt is added in an aqueous solution or suspension.

11. A process as claimed in claim 10 wherein the substance added is an aqueous solution of sodium hydroxide, an aqueous slurry of magnesium hydroxide or an aqueous solution of sodium aluminate.

12. A process as claimed in any of claims 1 to 11 wherein the substance is added in such an amount that a solid peroxyacid having a peroxyacid content of from 2.5 to 85.4% is obtained.

13. A process as claimed in any of claims 1 to 12 wherein the substance is added at a temperature of from 0 to 300C.

14. A process as claimed in claim 1 3 wherein the substance is added at a temperature of from

1 5 to 200C.

1 5. A process as claimed in any of claims 1 to 14 which comprises the additional steps of removing and drying the precipitated peroxyacid coated with the sulphate salt as a desensitizing agent.

1 6. A process as claimed in claim 1 5 wherein the carboxylic acid is azelaic acid and the substance added is sodium hydroxide, magnesium hydroxide or sodium aluminate, the precipitated diperoxyazelaic acid obtained being coated with sodium sulphate or magnesium sulphate.

1 7. A process for the production of a percarboxylic acid substantially as described with particular reference to any one of Examples 1 to 6.

1 8. A process for the production of a percarboxylic acid substantially as described with particular reference to any of Examples 7 to 12.

1 9. A storage stable and desensitized percarboxylic acid when prepared by a process as claimed in any of claims 1 to 18.

20. A composition comprising at least one aliphatic and/or aromatic percarboxylic acid coated with at least one sulphate salt in an amount effective to act as a desensitizing agent for the percarboxylic acid.

21. A composition as claimed in claim 20 wherein the percarboxylic acid is a diperoxyalkanedioic acid having at least 6 carbon atoms.

22. A composition as claimed in claim 21 wherein the diperoxyalkanedioic acid is diperoxyazelaic acid, diperoxysuberic acid, diperoxyadipic acid, diperoxysebacic acid or diperoxy 1,12-dodecanedioic acid.

23. A composition as claimed in claim 22 wherein the diperoxyalkanedioic acid is diperoxyazelaic acid.

24. A composition as claimed in claim 23 wherein the diperoxyazelaic acid is present in a quantity of from 2.5 to 85.4% of the total quantity of coating agent and diperoxyazelaic acid.

25. A composition as claimed in claim 20 wherein the percarboxylic acid is an aromatic carboxylic acid corresponding to the following general formula:-

wherein X represents from 0 to 5 substituents which may be the same or different and which may be a C00H group, a C14 alkyl group, a 0t-4 alkoxy group and/or a halogen atom.

26. A composition as claimed in claim 25 wherein the aromatic carboxylic acid is benzoic acid, isophthalic acid, or mellitic acid.

27. A composition as claimed in any of claims 20 to 26 the sulphate is an alkali metal sulphate, an alkaline earth metal sulphate, sodium aluminium sulphate or a mixture thereof.

28. A composition as claimed in claim 27 wherein the sulphate is sodium sulphate or magnesium sulphate.