WO2013178289A1

WO2013178289A1 - Stabilization of phthalimido percarboxylic with lithium salts

Info

Publication number: WO2013178289A1
Application number: PCT/EP2012/060448
Authority: WO
Inventors: Amila Bilic; Johannes Georg Winter
Original assignee: Ecolab USA Inc
Current assignee: Ecolab USA Inc
Priority date: 2012-06-01
Filing date: 2012-06-01
Publication date: 2013-12-05
Anticipated expiration: 2014-12-01
Also published as: EP2855653B1; EP2855653A1; ES2595180T3; EP2855653B8

Description

Stabilization of phthalimido percarboxylic acids with lithium salts

FIELD OF THE INVENTION

The present invention relates to a mixture for use as a bleaching agent comprising at least one phthalimido percarboxylic acid and at least one lithium salt, to a detergent composition comprising said mixture, and to the use of at least one lithium salt for stabilizing a phthalimido percarboxylic acid in a detergent composition.

BACKGROUND OF THE INVENTION

In the past, organic peracids have encountered increasing interest in the industrial field, among others due to their excellent properties as bleaching agents in detergent formulations. Therefore, a large number of publications are concerned with organic peracid compounds endowed with the required property of sufficient bleaching activity, said characteristic being essential for an industrial application and a widespread use of such compounds. Thus, many organic straight-chain or cyclic mono- or dipercarboxylic acids are known and used, e.g. in detergent compositions.

A problem with the widespread use of organic peracids arises from their low thermal stability, which makes it necessary to physically or chemically stabilize these compounds. The organic peracids known so far show a significant decrease of active oxygen, even under conventional storage conditions. This is also the case with imido percarboxylic acids as described already in J. Chem. Soc. 1962, 3821 and Chem. Ind. 1961 , 469. Among the imido percarboxylic acids, phthalimido percarboxylic acids have gained a widespread use in industry, especially as bleaching agents in detergent compositions. However, addition of boric acid to phthalimido percarboxylic acids is considered necessary to guarantee a sufficient long-term stability.

As boric acid has become a chemical of high concern, it is to be expected that boric acid will be banned from use in domestic applications in the near future.

Consequently, there is a need for alternative ways of stabilizing phthalimido percarboxylic acids in detergent compositions without making use of boric acid. SUMMARY OF THE INVENTION

The present invention satisfies this need by providing a mixture for use as a bleaching agent comprising at least one phthalimido percarboxylic acid and at least one lithium salt. With the present invention, it is possible to stabilize phthalimido percarboxylic acids so as to minimize a decrease of oxygen under conventional storage conditions, but to avoid the use of boric acid. Thus, detergent compositions may be obtained showing sufficient bleaching activity over time.

DETAILED DESCRIPTION OF THE INVENTION

After extensive studies, the inventors have found that phthalimido percarboxylic acids can be stabilized by lithium salts. This is rather surprising since it was suggested by the prior art that phthalimido percarboxylic acids if not stabilized degrade following a radical reaction pathway.

Without wishing to be bound to any theory, it is assumed that phthalimido

percarboxylic acids in fact degrade by attack of nucleophiles. A plausible degradation scheme of phthalimido peroxyhexanoic acid (phthalimido percaproic acid, PAP) in alkaline conditions is shown in figure 1. According to figure 1 , PAP is degraded to 4- phthalimido-1-hexanol and carbon dioxide via an electrocyclic reaction. As a consequence, the presence of at least one lithium salt would prevent nucleophiles from degrading PAP either by excluding reactive nucleophiles, by blocking

nucleophilic reaction sites at PAP and/or by catching nucleophiles with electrophiles other than PAP.

Therefore, the present invention is directed to a mixture for use as a bleaching agent comprising at least one phthalimido percarboxylic acid and at least one lithium salt.

There is no restriction as concerns the chemical nature of the at least one lithium salt. Thus, the at least one lithium salt may be either organic or inorganic. Besides, the at least one lithium salt may be hydrous or anhydrous.

Therefore, the present invention also relates to the mixture described above, characterized in that it comprises at least one inorganic lithium salt. The present invention further relates to the mixture described above, characterized in that it comprises at least one organic lithium salt.

According to the present invention, it is preferred that the anion of the at least one lithium salt is rather non-nucleophilic. If the anion in question is too nuc!eophilic, it is assumed to compete against the lithium cation for interaction with the phthalimido percarboxylic acid. Suitable non-nucleophilic anions for use according to the present invention are hexafluorosilicate (SiF₆ ^2"), sulfite (S0₃ ^2"), hydrogensulfite (HS0₃ ^~), organosulfite (RS0₃ ^~), sulfate (S0₄ ^2"), hydrogensulfate (HS0₄ ^"), organosulfate (RS0₄ ^"), phosphate (PO4³ ), hydrogenphosphate (HPO4^2"). dihydrogenphosphate (H₂P0₄ ^"), tetrafluoro borate (BF₄ ^~), tetrachloro borate (BCI4^"), tetrabromo borate (BBr4^_ ), tetraiodo borate (Bl₄ ^"), tetraphenyl borate (B[C₆H₅]4^"), tetra(pentafluoro)pheny! borate (B[C₆F₅]4^"), hexafluorophosphate (PF₆ ^~), hexachloro aluminate (AICI₆ ^3"), hexabromo aluminate {AIBr₆ ^3'), corresponding anion of an organic acid {OC[0]R^'), wherein R is selected from the group of Ci to C30 substituted and unsubstituted, linear, branched, cyclic alkyl, alkenyl, aryl, alkylaryl, arylalkyl, alkenylaryl, arylalkenyl, and combinations thereof, wherein the sulfate anion represents the most preferred anion.

Therefore, the present invention also relates to the mixture described above, characterized in that it comprises at least one lithium salt is selected from the group consisting of lithium hexafluorosilicate (L^SiFe), lithium sulfite (U2SO3), lithium hydrogensulfite (L1HSO3), lithium organosulfite (Li₂RS0₃), lithium sulfate (Li₂S0₄), lithium hydrogensulfate (LJHSO4), lithium organosulfate (LiRS0₄), lithium phosphate (Li₃P0₄), lithium hydrogenphosphate {U2HPO4), lithium dihydrogenphosphate

(UH2PO4), lithium tetrafluoro borate (UBF4), lithium tetrachloro borate (LiBCI₄), lithium tetrabromo borate (LiBB^), lithium tetraiodo borate (UBI4), lithium tetraphenyl borate (LiB[C₆H₅]4), lithium tetra(pentafluoro)phenyl borate (LiB[C₆F₅]4), lithium

hexafluorophosphate (LiPF₆), lithium hexachloro aluminate (Li₃AICI₆), lithium hexabromo aluminate (Li₃AIBr₆), lithium salt of an organic acid (LiOC[0]R), wherein R is selected from the group of Ci to C₃₀ substituted and unsubstituted, linear, branched, cyclic alkyl, alkenyl, aryl, alkylaryl, arylalkyl, alkenylaryl, arylalkenyl, and combinations thereof. The present invention further relates to the mixture as described above, characterized in that it comprises lithium sulfate. Also, there is no restriction as concerns the chemical nature of the at least one phthalimido percarboxylic acid. Suitable phthalimido percarboxylic acids for use according to the present invention may be selected from the phthalimido

percarboxylic acids of the general formula (1), where n is an integer of from 1 to 5:

Thus, suitable phthalimido percarboxylic acids for use according to the present invention may be selected from the group consisting of phthalimido peracetic acid (n=1 ), phthalimido perpropionic acid (n=2), phthalimido perbutyirc acid (n=3), phthalimido peramylic acid (n=4) and phthalimido percaproic acid (n=5), wherein phthalimido percaproic acid (phthalimido peroxyhexanoic acid, PAP) represents the most preferred phthalimido percarboxylic acid.

Therefore, the present invention also relates to the mixture described above, characterized in that it comprises at least one phthalimido percarboxylic acid selected from the phthalimido percarboxylic acids of the general formula (I) above, where n is an integer of from 1 to 5. The present invention further relates to the mixture described above, characterized in that it comprises phthalimido percaproic acid (phthalimido peroxyhexanoic acid, PAP).

Phthalimido percarboxylic acids and especially phthalimido peroxycarproic acid may be prepared as described in EP 0 325 288 A1 and EP 0 349 940 B1 , respectively. Thus, a substrate selected from phthalimido carboxylic acids and anhydrides thereof having a structure corresponding to the desired percarboxylic acid, e.g. of the general formula (I), may be reacted with concentrated H2O2 in a reaction medium selected from concentrated H₂S0₄ and CH3SO3H or in an alkaline medium, and the

percarboxylic acid is then separated from the reaction mixture by conventional and known techniques.

In order to obtain optimum stabilization of the at least one phthalimido percarboxylic acid, the content of lithium salt in the mixture should range between 1 and 50 % by weight, preferably between 1 and 25 % by weight, more preferably between 1 and 10 % by weight, most preferably between 2 and 5 % by weight based on the total weight of the mixture.

Therefore, the present invention also relates to the mixture described above, characterized in that the content of lithium salt is between 1 and 50 % by weight, preferably between 1 and 25 % by weight, more preferably between 1 and 10 % by weight, most preferably between 2 and 5 % by weight based on the total weight of the mixture.

Advantageously, the weight ratio of phthalimido percarboxylic acid to lithium salt is between 20:1 and 1 :1 , preferably between 10:1 and 1 :1 , more preferably between 5:1 and 1 :1 , most preferably between 2:1 and 1 :1.

Therefore, the present invention also relates to the mixture described above, characterized in that the weight ratio of phthalimido percarboxylic acid to lithium salt is between 20:1 and 1:1 , preferably between 10:1 and 1 :1 , more preferably between 5:1 and 1 :1 , most preferably between 2:1 and 1 :1.

An especially expedient mixture for use as a bleaching agent comprises between 10 and 25 % by weight of phthalimido peroxyhexanoic acid (phthalimido percaproic acid, PAP) and between 2 and 5 % by weight of lithium sulfate based on the total weight of the mixture.

Therefore, the present invention also relates to the mixture described above, characterized in that it comprises between 10 and 25 % by weight of phthalimido peroxyhexanoic acid (phthalimido percaproic acid, PAP) and between 2 and 5 % by weight of lithium sulfate based on the total weight of the mixture.

The mixture comprising the at least one phthalimido percarboxylic acid and the at least one lithium salt according to the present invention may be manufactured in the form of an aqueous solution, gel, emulsion, paste, dispersion, powder, flake, granules, scales, pearls, tablets, solid block form, extrudates and other forms known in the art, but preferably represents a powder or a flake.

Therefore, the present invention also relates to the mixture described above, characterized in that the mixture is in the form of a powder or a flake. The mixture according to the present invention is particularly suitable as effective bleaching agent in detergent formulations.

Therefore, the present invention is also directed to the use of a mixture described above as a bleaching agent.

The present invention is further directed to a detergent composition comprising a mixture described above. The detergent composition may contain any additive or active ingredient commonly used in corresponding washing, cleansing and/or disinfecting agents like builders, surfactants, soaps, zeolites, hydrotropic agents, corrosion inhibitors, enzymes, optical brighteners, stabilizers, abrasives, perfumes, coloring agents.

The inventive mixture may be incorporated into the detergent composition either as such or in combination with further additives, for example phosphates, carbonates, zeolites, carboxymethylcellulose or filmbuilding agents like fatty acids, fatty acid amides or esters etc. in the forms mentioned above for the mixture.

It is preferred that the detergent composition is substantially free of boric acid, i.e. comprises less than 10 ppm, preferably less than 5 ppm, even more preferably less than 1 ppm, and most preferably less than 0,1 ppm boric acid.

Therefore, the present invention also relates to the detergent composition described before, characterized in that it comprises less than 10 ppm, preferably less than 5 ppm, even more preferably less than 1 ppm, and most preferably less than 0,1 ppm boric acid.

The detergent composition may be used as a laundry detergent, preferably as a textile detergent, and is not only suitable for generally washing laundry, but as well for disinfecting.

Besides, the detergent according to the present application may be used as cleanser and/or disinfectant for cleansing and disinfecting various kinds of hard surfaces like, for example, in the medicinal or institutional field, in the food preparing, processing and/or selling industry, in agriculture, in hotel business, catering trade and/or in public buildings and/or institutions. It may as well be useful in further applications in which a disinfected surface is required or desired and which are not explicitly mentioned herein. The surfaces supposed to become disinfected may be made of common materials mentioned in the state of the art like, for example, metal, glass, ceramic, plastic, (coated) wood.

Finally, the present invention relates to the use of at least one lithium salt for stabilizing a phthalimido percarboxy!ic acid in a detergent composition.

In the following, the stabilization of phthalimido peroxycarboxylic acids with lithium salts will be demonstrated without being restricted to these examples.

EXAMPLES

Example 1 :

A mixture for use as a bleaching agent comprising 86 % by weight of phthalimido peroxyhexanoic acid (phthalimido percaproic acid, PAP) and 14 % by weight of a stabilizing agent (example 1a: boric acid (comparative); example 1 b: sodium sulfate (comparative); example 1c: lithium sulfate) was tested for its long-term stability. Therefore, the amount of chemically active PAP in the respective mixture was determined after storage by 40 °C at 1 , 3, 7, 14, 21 , 28, 49, 84, 119, 161 and 2 0 days, respectively.

As can be taken from Table 1 , a mixture comprising lithium sulfate (example 1c) shows a significantly higher long-term stability of phthalimido peroxyhexanoic acid (phthalimido percaproic acid, PAP) than a mixture comprising sodium sulfate (example 1b).

Table 1 :

Activity of PAP %

Moreover, as can be taken from Figure 2, phthalimido peroxyhexanoic acid (phthalimido percaproic acid, PAP) can even more effectively be stabilized by a lithium salt according to the present invention (example 1c) than by boric acid conventionally used (example 1a).

Claims

1. Mixture for use as a bleaching agent comprising at least one phthalimido

percarboxylic acid and at least one lithium salt.

2. Mixture according to claim 1 , characterized in that it comprises at least one inorganic lithium salt.

3. Mixture according to claim 1 or 2, characterized in that it comprises at least one organic lithium salt.

4. Mixture according to any of claims 1 to 3, characterized in that it comprises at least one lithium salt selected from the group consisting of lithium

hexafluorosilicate (Li₂SiF₆), lithium sulfite {U2SO3), lithium hydrogensulfite (LJHSO3), lithium organosulfite (Li₂RS0₃), lithium sulfate (Li₂S0₄), lithium hydrogensulfate (LiHS0₄), lithium organosulfate (L1RSO4), lithium phosphate (Li₃P0 ), lithium hydrogenphosphate (Li₂HP0₄), lithium dihydrogenphosphate (LiH₂P0₄), lithium tetrafluoro borate (L1BF4), lithium tetrachloro borate (LiBCU), lithium tetrabromo borate (LiBBr ), lithium tetraiodo borate (LiBU), lithium tetraphenyl borate (LiBfCeHsk), lithium tetra(pentafluoro)phenyi borate

(LiB[C6F₅]₄), lithium hexafiuorophosphate (LiPFe), lithium hexachloro aluminate (Li₃AICI₆), lithium hexabromo aluminate (Li₃AIBr₆), lithium salt of an organic acid (LiOC[0]R), wherein R is selected from the group of Ci to C₃₀ substituted and unsubstituted, linear, branched, cyclic alkyl, alkenyl, aryl, alkylaryl, arylalkyl, alkenylaryl, arylalkenyl and combinations thereof.

5. Mixture according to any of claims 1 to 4, characterized in that it comprises lithium sulfate.

6. Mixture according to any of claims 1 to 5, characterized in that it comprises at least one phthalimido percarboxylic acid is selected from the phthalimido percarboxylic acids of the general formula (I)

where n is an integer of from 1 to 5.

7. Mixture according to any of claims 1 to 6, characterized in that it comprises phthalimido peroxyhexanoic acid (phthalimido percaproic acid, PAP).

8. Mixture according to any of claims 1 to 7, characterized in that the content of lithium salt is between 1 and 50 % by weight, preferably between 1 and 25 % by weight, more preferably between 1 and 10 % by weight, most preferably between 2 and 5 % by weight based on the total weight of the mixture.

9. Mixture according to any of claims 1 to 8, characterized in that the weight ratio of phthalimido percarboxylic acid to lithium salt is between 20:1 and 1 :1 , preferably between 10:1 and 1 :1 , more preferably between 5:1 and 1 :1 , most preferably between 2:1 and 1 :1.

10. Mixture according to any of claims 1 to 9, characterized in that it comprises between 10 and 25 % by weight of phthalimido peroxyhexanoic acid

(phthalimido percaproic acid, PAP) and between 2 and 5 % by weight of lithium sulfate based on the total weight of the mixture.

11. Mixture according to any of claims 1 to 10, characterized in that the mixture is in the form of a powder or a flake,

13. Detergent composition comprising the mixture according to any of claims 1 to 11.

14. Detergent composition according to claim 13, characterized in that it

comprises less than 10 ppm, preferably less than 5 ppm, even more preferably less than 1 ppm, and most preferably less than 0,1 ppm boric acid.

15. Use of at least one lithium salt for stabilizing a phthalimido percarboxylic acid in a detergent composition.