AU692667B2 - Peracid compositions - Google Patents

Description

S F Ref: 254509D1

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

F1~13- Name and Address of Applicant: Actual Inventor(s): Address for Service: Invention Title: Solvay Interox Limited Baronet Works Baronet Road Warrington Cheshire WA4 6HB UNITED KINGDOM Christopher Revell Spruson Ferguson, Patent Attorneys Level 33 St Martins Tower, 31 Market Street Sydney, New South Wales, 2000, Australia Peracid Compositions 0*

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The following statement is a full description of this invention, including the best method of performing it known to me/us:- 5845 LI Is~

I

1 Peracid Compositions The present invention relates to peracid compositions. During recent years, increasing attention has been paid by industry and the general public in Western Europe and North America to the environmental effects of the many substances that are employed in moder life. One of the classes of substances which have hitherto been widely employed comprises chlorine and oxychlorine derivatives thereof. Such compounds have been reported to generate under appropriate circumstances carcinogenic compounds and as a result, industry is seeking alternatives or replacements for such compounds in order to allay any residual public anxiety.

An alternative class of compounds comprises peroxygen compounds, of which one sub-class of especial interest comprises peracids which contain the moiety -CO-OOH.

Peracids like hydrogen peroxide enjoy the substantial advantage of generating oxygen, either as such or in an active form during its deployment rather than chlorine or active chlorine species upon which environmentalists currently cast doubts. Furthermore, for a range of purposes such as disinfection, oxidation and bleaching, many of which are encountered domestically, peracids are more effective in general than hydrogen peroxide.

A number of the peracids are either liquid themselves or are produced conveniently in aqueous solution.

According to the present invention there are provided aqueous compositions 20 comprising up to about 40% w/w of a peracid compound at least partly in solution and a S quaternary ammonium salt, characterised in that the quaternary ammonium salt is a nonhalide salt.

The peracid compositions according to the present invention comprise a non-halide salt of a quaternary ammonium compound. Preferably a quaternary ammonium 25 methosulphate is employed.

By the use of the present invention it is possible to obtain solutions in which the peracid decomposes by not more than an acceptable extent during storage. In other words, the composition enjoys chemical stability.

*e e [N:\libff]00910:MCN I Woo The invention is intended particularly for soluble peracids. However, it will be recognised that the invention may alternatively be employed to compositions containing less or even poorly soluble peroxyacids such as those containing at least 8 carbons.

In particular, though, the system is applied to compositions containing soluble peracids, which may include low molecular weight aliphatic peroxyacids, for example containing up to 6 carbon atoms, of which especially preferred examples comprise peracetic acid and perpropionic acid. Other examples include perbutyric acid, persuccinic acid and perglutaric acid. The compositions may alternatively include soluble aromatic peroxyacids, such monoperphthalic acid, or sulphoperbenzoic acid. A mixture of peracids may be employed, if desired.

The peracid may be present in a wide range of concentrations, for example up to about 40%. For any component, herein is by weight based on the total weight of the composition, unless specifically stated otherwise. The lower limit is at the discretion of the user, but is normally not below about The invention is particularly applicable to ready to use compositions containing a low concentration of peracid, and for example compositions intended for application for cleansing and/or disinfecting 25 purposes to hard surfaces and particularly to non-horizontal surfaces. Such dilute compositions typically contain from 0.25 to about 5% by weight of peracid, for example peracetic acid and in a number of practical embodiments the peracid content will be from about 0.5 to It will be recognised 30 that such compositions may contain a significant concentration of hydrogen peroxide, which may, for example, comprise from about 1 to 12% of the composition, and in a number of embodiments from 3 to The peracid compositions, and particularly those S 35 containing aliphatic peracids are often conveniently derived by oxidation of the corresponding aliphatic carboxylic acid with aqueous hydrogen peroxide, and will often contain residual amounts of both the carboxylic acid and hydrogen 167xp-d peroxide. Thus, the compositions may contain up to 40% of the corresponding carboxylic acid and up to 40 hydrogen peroxide, with a minimum water content usually of However, in dilute peracid solutions, the concentration of the carboxylic acid and of hydrogen peroxide each tend to be selected in the range from about 1 to 12%. The total concentration of carboxylic acid plus percarboxylic acid is often from 3 to 20% and in many instances from 3 to 15%. It is often convenient to restrict the concentration of hydrogen peroxide to no greater than In many preferred compositions, equilibrium amounts of carboxylic acid, percarboxylic acid and hydrogen peroxide are present.

According to a second aspect of the present invention there is provided a process for preparing a peracid composition by introducing therein a non-halide salt of a quaternary ammonium compound.

The pH of the composition is desirably at least 1, approximately, and in practice the pH is normally not higher than about 4.5. A preferred pH range for the compositions comprise from about pH 3 to 4.5. Advantageously, many compositions such as dilute peracetic acid compositions attain that range without any further adjustment.

The compositions may include one or more stabilisers for peracids and/or hydrogen peroxide so as to encourage the 9o'- 25 chemical stability of the composition. Known stabilisers for peroxy compounds include aminopolycarboxylic acids, such as EDTA and DTPA, or N-heterocyclic aromiatic carboxylic acids such as quinolinic acid, picolinic acid and dipicolinic acid.

Particularly effective stabilisers comprise organic 30 polyphosphonic acids, including hydroxyethylidenediphosphonic acid and aminopolymethyiene phosphonic acids.

The latter often satisfy the general formula:

X

2 N-(-CHR-CHR-NX-)n-NX2 in which X represents -CH 2

-PO

3

H

2

R

represents H or the two R substituents combine to complete a 35 cyclohexane ring, and n is an integer from 1 to 3. Examples of the formula include ethylenediaminetetra- (methylene phosphonic acid), diethylenetriaminepenta- (methylene 167xp-d phosphonic acid) and cyclohexanediaminetetra- (methylene phosphonic acid).

In addition to the foregoing components, the composition may also contain one or more surfactants, for example amine oxides, and additionally or alternatively, one or more perfumes and/or dyes, preferably selected at least partly on the basis of resistance to oxidation.

Desirably, the pH of the solution is measured and adjusted, if necessary, by introduction of the appropriate choice from a mineral acid if the solution is insufficiently acid or an alkali if the solution is too acid.

The process of the present invention can be conducted at any convenient temperature, for example at the prevailing ambient temperature which is typically in the range of from 10 to 35 0 C. Alternatively, the mixture may be gently heated to not higher than about 50 0 C so as to encourage rapid distribution of the quaternary ammonium salt and the mixture eee thereafter permitted to cool to ambient.

*Some of the compositions of the present invention, and particularly those having a viscosity in the region of about 200, preferably about 250, to 600cPs are intended for application domestically to surfaces, such as non-horizontal surfaces, which it is desired to disinfect and clean, thereby taking advantage of the disinfectant properties of the 25 peracid and the cleansing properties of the detergents.

Accordingly, a third aspect of the present invention comprises the use the aforementioned invention compositions .o for disinfecting and cleansing by applying the composition to a hard surface and permitting contact to be maintained until ee 30 at least some disinfection has occurred.

The invention compositions may be applied using conventional means and will also take into account the physical state of the composition, particularly whether it is a viscous pourable liquid or a gel. Thus, in its simplest, the compositions may be poured dr smeared onto a distributor such as a cloth or sponge and applied to a receiving surface by passage of distributor across the surface. Alternatively, compositions which have a sufficiently low viscosity for them 167xp-d to be pourable, may be forced through a distributing nozzle directly onto the receiving surface, for example by squeezing a resilient deformable storage container. Compositions in gel form may be applied by a spatula or like article or as indicated previously by incorporation in a host composition or block.

The surfaces onto which the compositions may be applied are often domestic and especially in the kitchen and other locations in which micro-organisms may be found. Suitable receptive surfaces are usually made from wood, glass, ceramics, plastic laminates and metal, and include work surfaces, sinks, pipework, walls, floors, and especially toilet bowls. It will be recognised, though, that similar potentially infected surfaces may be found in non-domestic situations, such as in commercial kitchens, food processing apparatus or containers or brewery or distillery vessels or hospitals or in animal or poultry-rearing establishments or in glass houses or other areas where the maintenance of hygienic conditions is important. The present invention 20 includes the use of invention compositions in such nondomestic situations.

The compositions may subsequently be removed from the surfaces by water washing, possibly applied using a cloth, sponge or like article.

A further use for a composition is to form it into a block and suspend it, either as such or within a permeable container, within a liquid medium that it is desired to disinfect, such as process water, industrial circulating water or domestically the water supply to a toilet.

.o 30 Having described the invention in general terms, specific embodiments thereof will now be described in greater detail by way of example only.

For use in the Example and Comparisons, a batch of silicate solution was made dissolving sodium silicate powder having an SiO 2 :Na 2 O mole ratio df 2:1, obtainable from Joseph Crossfield under their trade name Crystal C Powder to a concentration of 40%. The solution contained on analysis Fe.

167xp-d Comparison 1 In this Comparison, a thickened peracid composition was made by stirring at laboratory ambient temperature (about 22 0 the aforementioned silicate solution (13g) and hydroxyethylidene-diphosphonic acid available under the Trademark DEQUEST grade 2010 (100ppm) into a solution of peracetic acid available from Interox Chemicals (100g) which analysed as peracetic acid acetic acid hydrogen peroxide and the balance water. The resultant composition had a pH of about 3.9, which rose to about pH after 20 days storage. After 16 weeks, the composition had a viscosity measured using a Brookfield synchroelectric viscometer of 80,000cPs. The available oxygen (Avox) of the composition was measured on production and after 16 weeks storage at 22 0 C using a conventional ceric sulphate/sodium thiosulphate technique. By comparing the two analyses, it was found that the composition had retained 47% of its Avox.

Example 2 In this Example, Comparison 1 was repeated, additionally incorporating an alkylammonium methosulphate (2g) available from Stepan under their trademark STEPANQUAT F. The resultant composition had a viscosity of 22,000 cPs after 16 weeks storage at 22 0 C and had retained 99% of its Avox.

Comparison 3 In this Comparison, Example 2 was repeated, incorporating an amine oxide (2g) in place of the alkylammonium methosulphate. After 16 weeks storage at 22 0 C, the 30 composition had a viscosity of 3000 cPs and had retained 72% of its Avox.

167xp-d

Claims (14)

1. An aqueous composition comprising up to about 40% w/w of a peracid compound at least partly in solution and a quaternary ammonium salt, characterised in that the quaternary ammonium salt is a non-halide salt.

2. A composition according to claim 1, characterised in that the quaternary ammonium salt is a quaternary ammonium methosulphate.

3. A composition according to claim 1 or claim 2, characterised in that the peracid is peracetic acid.

4. A composition according to any one of claims 1 to 3 characterised in that the composition contains from 0.25 to 5% w/w peracid.

A composition according to any one of claims 1 to 4 in that the composition contains amounts of a carboxylic acid and hydrogen peroxide each selected in the range of from 1 to 12% w/w.

6. A composition according to claim 5, characterised in that the combined proportions of peracid and carboxylic acid is in the range of from 3 to 15% w/w.

7. An aqueous composition comprising up to about 40% w/w of a peracid compound at least partly in solution and a quaternary ammonium salt, substantially as herein described with reference to Example 2.

8. A process for preparing a peracid composition by introducing therein a non- halide salt of a quaternary ammonium compound.

9. A process according to claim 8 characterised in that the quaternary ammonium salt is a quaternary ammonium methosulphate.

10. A process according to claim 8 or claim 9 characterised in that the peracid Scomposition is a peracetic acid composition. 25

11. A process according to any one of claims 8 to 10 characterised in that the composition contains from 0.25 to 5% w/w peracid.

12. A process according to any one of claims 8 to 11 characterised in that the composition contains amounts of a carboxylic acid and hydrogen peroxide each selected in the range of from 1 to 12% w/w. 30

13. A process according to claim 12 characterised in that the combined proportions of peracid and carboxylic acid is in the range of from 3 to 15 w/w.

14. A peracid composition produced by a process according to any one of claims 8 to 13. [N:\libff]00910:MCN 8 A disinfectant comprising an aqueous composition of any one of claims 1 to 7, or a peracid composition of claim 14. Dated 9 April, 1998 Solvay Interox Limited Patent Attorneys for the Applicant/Nominated Person SPRUSON FERGUSON 4 4~ .4 .4 4 4 4 4. 4 4 4. 4 0444 4* e 4 4 4 44 4 4. 4 4* 4 4 4. .4 4 4@ 4 4 444 0 4 4 4 I' [N.\libffl00910:MCN t 0 Abstract Peracid Compositions Peracid compositions comprising a quaternary ammonium salt are provided. The quaternary ammonium salt is a non-halide salt, preferably a quaternary ammonium methosulphate. The peracid is preferably an equilibrium solution of peracetic acid. The compositions can be employed as disinfectants, particularly for hard surfaces. a to