European Patent Office Office Europeenpeen Des Brevets EP 0 751 933 B1

Europaisches Patentamt (19) European Patent Office Office europeenpeen des brevets EP 0 751 933 B1

(12) EUROPEAN PATENT SPECIFICATION

(45) Date of publication and mention (51) intci.6: C07C 409/24, C07C 407/00, of the grant of the patent: A01N 37/16 02.06.1999 Bulletin 1999/22 (86) International application number: (21) Application number: 94910062.2 PCT/NL94/00059 Date of 09.03.1994 (22) filing: (87) International publication number: WO 95/24388 (14.09.1995 Gazette 1995/39)

(54) A METHOD FOR THE PREPARATION OF AQUEOUS SOLUTIONS CONTAINING PERFORMIC ACID AS WELL AS THEIR USE VERFAHREN ZUR HERSTELLUNG WASSERIGER PERAMEISENSAURELOSUNGEN UND DEREN VERWENDUNG PROCEDE DE PREPARATION DE SOLUTIONS AQUEUSES RENFERMANT DE L'ACIDE PERFORMIQUE ET LEUR UTILISATION

(84) Designated Contracting States: (74) Representative: de Bruijn, Leendert C. BE CH DE ES FR GB IT LI NL Nederlandsch Octrooibureau P.O. Box 29720 (43) Date of publication of application: 2502 LS Den Haag (NL) 08.01.1997 Bulletin 1997/02 (56) References cited: (73) Proprietor: Kemira Chemicals B.V. DE-A- 1 962 671 FR-A- 2 008 896 3198 LS Europoort-Rotterdam (NL) FR-A- 2 101 175

(72) Inventors: • DATABASE WPI Week 8609, Derwent • MATTILA, Tapio Publications Ltd., London, GB; AN 86-060814 & NL-2597 CS The Hague (NL) SU,A,1 172 514 (TARTU UNIV) 15 August 1985 • AKSELA, Tapio FIN-02360 Espoo (Fl)

DO CO CO O)

Is- Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice the Patent Office of the Notice of shall be filed in o to European opposition to European patent granted. opposition a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. a. 99(1) European Patent Convention). LU

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Description

[0001] The present invention relates to a method for the preparation of aqueous solutions containing performic acid formed by reaction of formic acid and hydrogen peroxide in the presence of a catalyst. 5 [0002] Such a method is known from the book Organic Peroxides, Vol. 1 , ed. by B. Swern in 1970 (Wiley Interscience). Dilute performic acid solutions suitable for disinfection are most conveniently prepared by mixing 70-90 wt.% of formic acid and 35-50 wt.% of hydrogen peroxide. Performic acid is unstable at higher concentrations and therefore it is usually prepared by mixing solutions of formic acid and hydrogen peroxide just prior to use (in situ preparation). Ac- cording to Swern an acid catalyst may be used. 10 [0003] The bactericidal and sporicidal disinfectant properties of performic, peracetic and perproponic acid has been described by Merka et al., in J. Hyg.Epidem. Microbiol. Imwunol, 1965 (IX) 220. Performic acid has demonstrated supe- rior results in the studies concerning the fungicidal (mycocidal) properties of these acids (J. Hyg.Epidem. Microbiol. Immunol. 1968, 12, 115). [0004] The exceptional microbicidal properties of performic acid have later been described in EP-A-0 231 623. 75 [0005] A specific use of aqueous performic acid containing solutions is described in not prepublished Dutch patent application 9300445. This reference relates to a method for preventing and combating harmful microorganisms such as fungi, viruses, bacteria, yeasts and algae in water circulation systems, wherein the water including feed solutions and drain water, has a disinfectant added to it which at least comprises performic acid. The contents of this Dutch patent application is incorporated here by reference. 20 [0006] It is an object of the present invention to increase the equilibrium concentration of performic acid in aqueous solution of formic acid and hydrogen peroxide. [0007] This object was achieved by the use of a compound containing at least one ester group and/or

•C-0-

group differing from a carboxylic acid group as a catalyst. 30 [0008] FR-A-2 101 175 (= US-A-3 845 112) also relates to a process for the preparation of aqueous solutions containing percarboxylic acids such as performic acid. This process is performed by reacting a carboxylic acid anhydride or a carboxylic acid with hydrogen peroxide in the presence of a phosphorous compound of the following general formula (I)

35 O

R, - (X)m - P - (Z)„ - R;

(Y)„ - R2

wherein:

X, Y and Z each individually is an oxygen atom, or an >N-C-|-C6 alkyl group, or an >N-C4-C7 cycloalkyl group, so R2 and R3 each individually is C-,-C6 alkyl or C4-C6 cycloalkyl radical which is optionally substituted by at least one halogen, OH, C-1-C4 lower alkoxy, CN or phenyl; or a phenyl radical which is optionally substituted by at least one halogen, OH, C-1-C4 lower alkoxy, carbo C-1-C3 lower alkoxy or CN, or two of them together comprise an alkylene radical forming a 5- to 7-membered heterocyclic ring containing phosphorus as a hetero atom and up to two additional hetero atoms. 55 [0009] Consequently, the present invention relates to a method for the preparation of aqueous solutions containing performic acid formed by reaction of formic acid and hydrogen peroxide in the presence of a catalyst, characterized in that the catalyst is a compound containing at least one ester group and/or

2 EP 0 751 933 B1

0 •c-o-

5 group differing from a carboxylic acid group. [0010] The compound may be used in catalytic amounts, which expression is well-known to men skilled in the art. However, it is preferred that a minimum amount of 10 ppm, calculated on the aqueous solution, is used. In general an amount of more than 10.000 ppm will not bring additional advantages. The particularly preferred range is 200-5000 ppm, again calculated on the total aqueous solution containing the reactants. 10 [0011] Preferably, the catalytic compound is a carboxylic acid ester which is not toxic. However, other ester compounds such as sulfate esters, sulfonate esters/lactones and phosphate esters and similar compounds may be suc- cessfully used. [0012] According to a preferred embodiment of the method of the invention the catalytic compound is selected from the group consisting of carboxylic acid esters where the carboxylic acid is: 15 a) aromatic or aliphatic C-|-C20 carboxylic acid; b) aromatic or aliphatic di- or polyfunctional carboxylic acid;

and wherein the alcohol part is 20 a) aliphatic or aromatic C-,-C6 mono- of polyfunctional alcohol, b) sugar alcohol, c) polymer containing hydroxyl groups.

25 [0013] Suitable are a.o. compounds like glyceryl mono-, di- and triesters, wherein the carboxylic acid is C-|-C20 carboxylic acid, polymers such as (partially hydrolysed) polyvinylacetate. [0014] The use of the catalyst in accordance with the invention causes an enormous increase, e.g. of 100-300 % of the concentration of performic acid. Consequently, performic acid containing preparations prepared in accordance with the invention are more efficient than the prior art solutions. 30 [0015] The present invention also relates to an aqueous solution containing performic acid, formic acid, hydrogen peroxide as well as a compound containing at least one ester group and/or

group differing from a carboxylic acid group. The same preferences as mentioned with respect to the method of the invention can be mentioned here. 40 [0016] Further, the invention relates to the use of the above aqueous solutions of the invention for sterilization, san- itation and disinfection purposes. In this respect reference is e.g. made to the above cited EP-A-0 231 623 and NL 9300445. [0017] It appeared from many tests that any compound of the ester type may be used with a certain degree of success. An average chemist will immediately understand what is meant by "ester type". 45 [0018] The inventors find the effect of the ester type compound on the amount of performic acid in the solution surprising. [0019] The invention is explained in more detail in the following examples.

Example 1 50 [0020] A 35 % (w/w) solution of hydrogen peroxide (515 g, 5.38 mol) is added dropwise with stirring in 98 % (w/w) formic acid (100 ml, 122 g, 2.65 mol) at room temperature. The resulting solution was stirred for 30 minutes at room temperature and diluted with deionized water (1911 g). The solution was divided into 50 ml portions and 50 mg of the following alkyl esters of carboxylic acids were added into each solution: 55 Sample Carboxylic acid ester 1 . no additives

3 EP 0 751 933 B1

(continued) Sample Carboxylic acid ester 2. caproic acid mono- and diglyceride (Grinstedt TS-T 104) 3. 1 ,2,3-triacetoxypropane 4. ethyl acetate 5. methyl formate 6. sorbitan monolaurate (ICI Span 20) 7. dibutyl phthalate

[0021] The solutions were allowed to stand at room temperature and the concentrations of hydrogen peroxide and performic acid were determined by titration with Ceric sulfate and sodium thiosulfate, respectively according to the method of Swern et al. (Swern, Organic Peroxides, Vol. 1, page 501, Wiley Interscience, 1970). The concentrations 15 obtained by titrations are collected in tables 1 and 2.

Table 1 Concentrations of performic acid obtained from the samples 1-6, 1 hour after dilution. Sample No. additive 1) performic acid (g/l) 1 . no additives 3.41 2. monoglyceride 6.51 3. 1 ,2,3-triacetoxypropane 6.51 4. ethyl acetate 6.51 5. methylformate 6.20 6. sugar ester 6.82 7. dibutyl phthalate 1- 2 11.16 1 ) concentration 2500 mg/l 30 2) titrated after 4 hours stirring at room temperature.

Table 2 Concentrations of performic acid obtained from the samples 24 hours after dilution Sample No. additive performic acid (g/l) 1. no additives 2.63 2. monoglyceride 6.36 3. 1 ,2,3-triacetoxypropane 7.13 4. ethyl acetate 7.29 5. methylformate 6.66 6. sugar ester 5.43

Example 2

[0022] A 30 wt.% solution of hydrogen peroxide (61 0 g, 5.38 mol) was added dropwise into 98 wt.% formic acid (1 00 ml, 122 g, 2.65 mol). The solution was stirred at room temperature for 30 minutes, whereafter it was divided into five portions. Carboxylic acid esters listed in Table 3, were added into the solutions and they were stirred at room temperature for 4 hours. Concentrations of performic acid and hydrogen peroxide were determined by using the method mentioned above.

Table 3 Concentrations of performic acid obtained from the samples 4 hours after dilution. Sample additive (mg/l) performic acid (mg/l) 1. no additives 27.28

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Table 3 (continued) Concentrations of performic acid obtained from the samples 4 hours after dilution. Sample additive (mg/l) performic acid (mg/l) 2. ethyl acetate 1300 31.00 3. ethyl propionate 1500 28.52 4. dibutyl phthalate 2500 31.93 6. glycolic acid butyl ester 1500 44.64

Claims

1 . A method for the preparation of aqueous solutions containing performic acid formed by reaction of formic acid and hydrogen peroxide in the presence of a catalyst, characterized in that the catalyst is a compound containing at least one ester group and/or

■C - 0-

group differing from a carboxylic acid group.

2. The method according to claim 1, wherein the catalyst is present in an amount of 100-5000 ppm, calculated on the aqueous solution.

3. The method according to claim 1 or 2, wherein the catalytic compound is a carboxylic acid ester.

4. The method according to any of claims 1 -3, wherein the catalytic compound is selected from the group consisting of carboxylic acid esters where the carboxylic acid is:

a) aromatic or aliphatic C-|-C20 carboxylic acid; b) aromatic or aliphatic polyfunctional carboxylic acid;

and wherein the alcohol part is:

a) aliphatic or aromatic mono- or polyfunctional C-,-C6 alcohol; b) sugar alcohol, c) polymer containing alcohol groups.

5. Aqueous solutions containing performic acid, formic acid, hydrogen peroxide, and a compound containing at least one ester group and/or

0 •C - 0-

group differing from a carboxylic acid group.

6. Use of a solution according to any of the preceding claims for sterilization, sanitization and disinfection purposes.

Patentanspriiche

1. Verfahren zur Herstellung wassriger, Perameisensaure enthaltender Losungen, die durch Umsetzung von Amei- sensaure mit Wasserstoffperoxid in Gegenwart eines Katalysators erhalten werden, dadurch gekennzeichnet, EP 0 751 933 B1

dal3 der Katalysator eine Verbindung ist, die mindestens eine Estergruppe und/oder eine zu einer Carbonsaure- gruppe unterschiedliche

? ♦ c— o*

10 -Gruppe aufweist.

2. Verfahren nach Anspruch 1 , wobei der Katalysator in einer Menge von 1 00-5000 ppm, berechnet auf die wassrige Losung, vorliegt. is 3. Verfahren nach Anspruch 1 oder 2, wobei die katalytische Verbindung ein Carbonsaureester ist.

4. Verfahren nach einem der Anspruche 1-3, wobei die katalytische Verbindung aus einer Gruppe der Carbonsau- reester ausgewahlt ist, wobei die Carbonsaure ausgewahlt ist aus: 20 a) aromatischen oder aliphatischen C-|-C20-Carbonsauren; b) aromatischen oder aliphatischen polyfunktionellen Carbonsauren;

und der alkoholische Teil ausgewahlt ist aus: 25 a) aromatischen oder aliphatischen mono- oder polyfunktionellen C-|-C6-Alkoholen; b) Zuckeralkoholen; c) Alkoholgruppen enthaltenden Polymeren.

30 5. Wassrige Losungen, enthaltend Perameisensaure, Ameisensaure, Wasserstoffperoxid und eine Verbindung, die mindestens eine Estergruppe und/oder eine zu einer Carbonsauregruppe unterschiedliche

♦ c — o*

40 -Gruppe aufweist.

6. Verwendung einer Losung nach einem der vorhergehenden Anspruche fur Sterilisations-, Sanitar- und Desinfek- tionszwecke.

45 Revendications

1. Procede pour la preparation de solutions aqueuses contenant de I'acide performique forme par reaction d'acide formique et de peroxyde d'hydrogene en presence d'un catalyseur, caracterise en ce que le catalyseur est un so compose contenant au moins'un groupe ester et/ou un groupe -C(=0)-0- different d'un groupe acide carboxylique.

2. Procede selon la revendication 1, dans lequel le catalyseur est present en une quantite de 100 a 5000 ppm, calculee par rapport a la solution aqueuse.

55 3. Procede selon la revendication 1 ou 2, dans lequel le compose catalytique est un ester d'acide carboxylique.

4. Procede selon I'une quelconque des revendications 1 a 3, dans lequel le compose catalytique est choisi dans I'ensemble constitue par les esters d'acide carboxylique dans lesquels I'acide carboxylique est :

6 EP 0 751 933 B1

a) un acide carboxylique en C-, a C20 aromatique ou aliphatique; b) un acide carboxylique polyfonctionnel aromatique ou aliphatique; et dans lesquels la fraction alcoolique est :

a) un alcool en C1 a C6 mono- ou polyfonctionnel, aliphatique ou aromatique ; b) un alcool de sucre ; c) un polymere contenant des groupes alcools.

Solutions aqueuses contenant de I'acide performique, de I'acide formique, du peroxyde d'hydrogene, et un com pose contenant au moins un groupe ester et/ou un groupe -C(=0)-0- different d'un groupe acide carboxylique.

Utilisation d'une solution selon Tune quelconque des revendications precedentes, a des fins de sterilisation, d'asep tisation et de disinfection.