DE68901737T2 - ALKYLSULPHONYLPERCARBONIC ACIDS AND THE BLASTING AND CLEANING COMPOSITIONS CONTAINING THEM. - Google Patents

Description

The invention relates to storage-stable bleaching agents of the general structural formula

in which R is a linear or branched alkyl group and n is 1 or more. The invention also relates to washing, bleaching, cleaning and/or disinfecting compositions containing such bleaching agents.

European patent application No.0 267 175 generally describes sulfone peroxycarboxylic acids of the general formula

in which A and B are organic groups, A or B containing at least one C(O)-OOH group. According to European Patent Application No. 267 175, A and/or B may contain any one or more organic substituents, including alkyl, aralkyl (including cyclic, straight-chain or branched radicals), aryl groups and alkaryl groups. Organic substituents having 1 to 18 carbon atoms are preferred for A and B. European Patent Application No. 0 267 175 describes in its examples the bleaching and stability properties of various sulfone peroxycarboxylic acids including 3-decylsulfonylperoxypropionic acid.

European patent application No. 0 166 571 contains a broad description of peracids which can be used as cleaning agents and Bleaching agents for laundry. In the patent application, peracids of the following general formula

[RX]mAOOH

where R is hydrocarbon or alkoxylated hydrocarbon, x is O, SO₂, N(R')₂, P(R')₂, P(R')-O or N(R')-O (wherein R' is H or alkyl) and A is one of various carbonyl-containing radicals. Only three peracids (in the form of bleach activators) are actually prepared in the working examples of European Patent Application No. 166 571. In these three peracids, "X" always represents oxygen. The aim of the present invention is to provide certain alkylsulfonylperoxycarboxylic acids which have improved stability in their peracid form.

The bleaching agents of the present invention belong to the type specified above and are characterized in that the linear or branched alkyl group R contains 6 to 9 carbon atoms and n is an integer from 1 to 10 inclusive. Preferably, n = 2 or 3. More preferably, the alkyl group R contains 6 to 9 carbon atoms and n = 2. Specific examples of the alkyl groups of the present invention include, among others, n-hexyl, n-heptyl, n-octyl, t-octyl, 2-ethylhexyl, 3,5,5-trimethylhexyl, n-nonyl and t-nonyl.

The alkylsulfonylperoxycarboxylic acids of the present invention can be prepared by reacting a precursor carboxylic acid, such as alkylsulfonylcarboxylic acid, alkylmercaptosulfonylcarboxylic acid or alkylsulfoxylcarboxylic acid, with hydrogen peroxide in an acidic medium. The reaction mixture of carboxylic acid and hydrogen peroxide can be prepared by the presence of a additional acid, such as methanesulfonic acid or sulfuric acid. The alkylsulfonylcarboxylic acids and alkylmercaptocarboxylic acids can be prepared according to L. Rapoport et al., J.Am.Chem.Soc., Vol. 69, pp. 693-4 (1947). The alkylmercaptocarboxylic acids can also be prepared by one of the following processes:

(1) condensing a mercaptan with a halogen acid, a haloester or a halogenonitrile and subsequently hydrolyzing the reaction product;

(2) alkylating a mercaptocarboxylic acid with an alkyl halide;

(3) reacting a mercaptocarboxylic acid, a mercaptocarboxylic acid ester or nitrile with an alkene and subsequently hydrolyzing the reaction product, or

(4) Reacting a mercaptan with acrylic acid, acrylic acid ester or acrylonitrile and subsequent hydrolysis of the reaction product.

Specific precursor carboxylic acids useful in the present invention are alkylsulfonylcarboxylic acids of the following formula:

Alkylmercaptocarboxylic acids of the following formula

or alkylsulfoxylcarboxylic acids of the following formula

wherein R is a linear or branched alkyl group containing 6 to 9 carbon atoms and n is a number from 1 to 10 inclusive.

In addition, the alkylsulfonylpercarboxylic acids of the present invention can also be prepared in situ in a lye or solution for washing, bleaching, cleaning and/or disinfecting. Such in situ preparation of the compounds of the present invention is carried out in a similar manner as described in connection with the use of bleach activators (e.g. US Patents Nos. 3,163,606 and 4,412,934 and European Patent Application No. 202,698).

As mentioned above, the compound of the present invention is an effective bleaching agent. Accordingly, the compound can be used to advantage in bleaching, laundry, cleaning and/or disinfectant compositions. The amount of the present compound that can be used in such compositions depends on the intended use. Furthermore, it may be desirable to prepare mixtures or combinations of two or more compounds of the present invention to form a combined bleaching agent. For example, some compounds are more effective bleaching agents for hydrophobic stains, while others are more effective for hydrophilic stains. Bleaching agents can also be obtained by mixing or combining one or more compounds of the present invention with other effective bleaching agents.

Detergents containing bleaching agents of the present invention also contain surfactants. Suitable surfactants for use in the The present agents are the anionic, non-ionic and amphoteric surfactants which are generally used for this purpose. Examples of these are: soaps made from synthetic or natural fatty acids, alkylbenzene sulfonates, aliphatic sulfonates, addition products of ethylene oxide and fatty alcohols, ethylene oxide/propylene oxide copolymers and betaines which contain carboxyl, sulfate or sulfonate groups. In addition to the present bleaching agent and at least one surfactant, detergents according to the present invention can contain the additives usually used for detergents, such as sequestering agents, fillers, builders, enzymes, fluorescent and optical brighteners, also called "optical bleaches", soil suspending agents, foam suppressors and the like. In practice, the detergent composition according to the invention may vary in its external form between powdery and granular and may be obtained by known methods, such as crystallization or spray drying of an aqueous slurry, or by mechanical mixing or combining of the substances.

Solid detergents and/or bleaches containing alkylsulfonylpercarboxylic acids may also contain binders if mechanical strength or stability is desired. For safety reasons, heat control agents may be used in the compositions of the present invention. The alkylsulfonylpercarboxylic acids of the present invention may also be formulated as liquid suspensions, similar to that described in European Patent Application No. 176 124.

The following examples illustrate the invention.

example 1

This example describes a laboratory method used to prepare the alkylsulfonylpercarboxylic acid bleaches of the present invention. The preparation of three representative compounds is summarized in Table 1 below. To prepare the compounds of Table 1, a mixture of 50 ml of methanesulfonic acid (MeSO₃H-98%) and 0.075 moles of the precursor alkylsulfonylcarboxylic acid for each compound was prepared. The precursor alkylsulfonylcarboxylic acids for compounds 1, 2, 3 and A were n-hexylsulfonylpropionic acid, n-octylsulfonylpropionic acid, n-nonylsulfonylpropionic acid and n-decylsulfonylpropionic acid, respectively. Compound A serves as a comparative example since it is described in European Patent Application No. 0 267 175. To each of the constantly stirred mixtures of methanesulfonic acid and the respective carboxylic acid, 0.225 moles of H2O2 was added over a period of 30 minutes. The temperature of the reaction mixture was maintained at 30°C. Stirring was then continued at 30°C for an additional 60 minutes and the reaction mixture was poured into 200 ml of ice water. The resulting peracid particles were isolated by filtration (G-3 glass filter). The resulting wet cake was dissolved in a 1:1 mixture of dichloromethane and ethyl acetate and then washed with water until the effluent was neutral. Each peracid was isolated as a white powder by removing the solvents under vacuum. The yield from each reaction was determined by standard iodometry procedures (based on active oxygen). Note that the order in which the alkylsulfonylcarboxylic acid, the additional acid (such as methanesulfonic acid), and H2O2 were added was not the same. combined, is not critical for the formation of the desired reaction product (alkylsulfonylpercarboxylic acid). The reaction product is therefore not dependent on the The order of mixing used in this example was followed for safety reasons. Table 1 Compound Number Compound Name Compound Formula Yield (%) n-Hexylsulfonylperoxypropionic acid n-Octylsulfonylperoxypropionic acid n-Nonylsulfonylperoxypropionic acid n-Decylsulfonylperoxypropionic acid o-Cetylperoxycarboxylic acid

The compound according to Example B is one of the compounds described in European Patent Application No. 0 166 571 and serves as a comparative example. Compound B was prepared according to the following method: To a mixture at 0ºC of 181.7 g of demineralized water, 0.47 g of metal ion separator (Dequest , 2060 S (50%)), 170.0 g of methanol, 215 mmol of NaOH (32.7%), 215 mmol H₂O₂ (69%) and 482.7 g CCl₄ were added with stirring 47.6 mmol cetyl chloroformate (97.5%) in 54.2 g CCl₄. The addition was carried out over a period of 90 minutes. During the addition the temperature was maintained at 0°C. Then stirring was continued at 0°C for an additional 4 hours. The resulting thick slurry was filtered through G-2 and washed 5 times with demineralized water. Filtration and washing were carried out at 0°C in a vacuum of 133 Pa (1 mm Hg) to give 12.5 g of solid material with an active oxygen content of 4.93% in a yield of 71.1%. A solution was prepared from 2.84 g of sodium peracid salt (active oxygen content = 3.68%) in 140 ml of acetic acid at 20°C. To this solution were added successively 100 ml of CCl₄ and 350 ml of demineralized water. The CCl₄ layer was separated and washed with 5 x 50 ml of demineralized water. After drying over MgSO₄ 2H₂O, titration and removal of CCl₄ in vacuo, the peroxycarboxylic acid obtained was present as a solid residue with an active oxygen content of 4.29% in a yield of 91% based on the sodium salt. The structure was confirmed by IR and 1 H NMR spectroscopy.

Example 2

Bleaching agents with low loss of active oxygen over a period of time are preferred for laundry, bleaching, cleaning and disinfecting compositions. Bleaching agents that exhibit low loss of active oxygen are often referred to as "shelf stable". The storage stability of the bleaching agents of the present invention was compared to that of a known bleaching additive by storing compounds 1, 2, A and B under the conditions indicated in Tables 2A and 2B. The active oxygen of each compound was determined at the indicated time intervals by standard iodometric methods. The results are summarized in Tables 2A and 2B. A comparison of Tables 2A and Figure 2B shows the clear and surprising superiority in storage stability of the compounds of the present invention. This is true even though the compounds of the present invention were stored at significantly higher temperatures than Compound B, and higher temperatures accelerate the loss of active oxygen. Table 2A Comb. Storage Temp.(ºC) Initial AO.(%) Rel.AOLoss(%) Table 2B Connected storage temp.(ºC) Initial AO(%) Rel.Loss AO (%)

Example 3

It is also important that bleaching agents retain their storage stability when combined in detergent compositions. To demonstrate such stability of the bleaching agents of the present invention, the storage stability of Compound 2 in combination with a standard test detergent ("IEC Detergent") was compared with that of the commercially available bleach "DPDA (desensitized) 12% (12 wt% diperoxydodecanedioic acid and 88 wt% Na₂SO₄). "DPDA (desensitized) 12%" is hereinafter referred to as "Compound C". The standard detergent had the following composition:

- 8% Linear alkyl (average C11½) benzenesulfonate, sodium salt

- 2.9% ethoxylated (14 EO) tallow alcohol

- 3.5% sodium soap (13-26% C₁₂₋₁₆; 74-78% C₁₈₋₂₂)

-43.7% sodium triphosphate

- 7.5% sodium silicate (SiO₂ : Na2O = 3.3 : 1)

- 1.9% magnesium silicate

- 1.2% carboxymethyl cellulose

- 0.3% sodium ethylenediaminetetraacetate

- 0.3% optical brightening agent for cotton (stilbene type)

-21% sodium sulfate

- 9.7% water.

Two test samples were prepared by adding 400 mg of compound 2 and 400 mg of compound C to two separate 600 mg samples of the IEC detergent. The active oxygen content of each sample is determined by standard iodometry methods and the samples are then stored for two weeks at 40ºC. After two weeks, compound 2 still contained 95% of its initial active oxygen content and compound C only 55% of its initial active oxygen.

Example 4

Two separate sets of laboratory test washes were conducted to demonstrate how the varying alkyl chain length of alkylsulfonylcarboxylic acids affects the bleaching effect of such acids on laundry. In the first set of laboratory test washes, a Linitest laboratory washing machine was used to test the bleaching effect of compounds 1, 2 and A as defined in Example 1. A comparative test wash was also conducted without the bleach additive of the invention. In all four laboratory test washes using the Linitest machine, fabric sections (4 g) stained with tea and red wine were washed with the detergent Tide for 30 minutes in 300 ml of water at 40ºC. The detergent concentration was 2.0 g/l. The concentration of alkylsulfonylcarboxylic acid (if present) was 20 ppm active oxygen. The bleaching effect was determined using a reflectometer. The reflectometer measures the light reflected in all directions at an angle of 45º when a tristimulus blue light beam is directed perpendicularly at a piece of fabric. The value measured by the reflectometer is called "reflectance". A higher reflectance indicates a better bleaching effect. The reflectance values for each of the four laboratory test washes using the Linitest device are shown in Table 3A. Analysis of the data presented in Table 3A indicates that the bleaching activity of compounds 1, 2 and 3 (n-hexylsulfonylperoxypropionic acid, n-octylsulfonylperoxypropionic acid and n-nonylsulfonylperoxypropionic acid, respectively) is better, or in the case of olive oil/soot, practically equal to the bleaching performance of compound A (n-decylsulfonylperoxypropionic acid).

In the second set of laboratory test washes, an ITT miniwasher was used to test the bleaching effect of Compounds 1 and 2 as defined in Example 1. The effect of multiple wash cycles was also tested. In each miniwasher test wash, 7 towels, each with 4 sections of stained fabric, were washed in a standard detergent (as defined in Example 3) for 10 minutes (per cycle) in 12 liters of water at 38°C. The detergent concentration was 1.25 g/liter. The alkylsulfonylcarboxylic acid concentration was 6 ppm active oxygen. Bleaching effect was determined using a reflectometer as described above. The measured reflectance values for each miniwasher test are shown in Table 3B. The data in Table 3B show that Compound 2 is a more effective bleaching agent than Compound 1. (Note that a Miniwasher test is more sensitive than one using the Linitest.) Furthermore, the data show that the better effect of compound 2 is more pronounced on hydrophobic stains (stains 4 - 7 of Table 3) than on hydrophilic stains (stains 1 - 3 of Table 3B). Table 3A % Reflectance Stains* Compound no bleach 1. Tea 2. Red wine 3. Berries 4. Olive oil/soot 5. Immediate green 6. Chlorophyll * Test coupons were obtained from the following sources: a. Coupons for stains 2 and 4 from the Swiss Federal Laboratories for Materials Science and Technology, St. Gallen, Switzerland. b. Coupon for stain 3 from the TNO Laundry Research Institute, Delft, Holland. c. Coupon for stain 5 from the Krefeld Laundry Research Institute, Federal Republic of Germany. d. Coupons for stains 1 and 6 were prepared by laboratory personnel. Table 3B % Reflectance Number of Wash Cycles Compound Stains* 1. Tea 2. Red wine 3. Berries 4. Raw cotton (no stains) 5. Olive oil/soot 6. Cocoa 7. Immediate green * Test coupons were obtained from the following sources: a. Coupons for stains 2, 4, 5 and 6 from the Swiss Federal Laboratories for Materials Science and Technology, St. Gallen, Switzerland. b. Coupon for stain 3 from the TNO Washing Research Institute, Delft, Holland. c. Coupon for stain 7 from the Krefeld Washing Research Institute, Federal Republic of Germany. d. Coupon for stain 1 was prepared by laboratory personnel.

Example 5

In this example, the bleaching effect of n-hexylsulfonylperoxypropionic acid (compound 1 as defined in example 1) is compared with the bleaching effect of the highly effective bleaching agent diperoxydodecanedioic acid (DPDA). To explain DPDA as a bleaching agent, reference should be made to the following publication:

"Diperoxydodecanedioic Acid (DPDDA) a New Bleaching Agent for Low-Temperature Laundry Process" by Dr. Peter Kuzel, Dr. Thomas Lieser and Dr. Manfred Dankowski, published in Seifen-Öle-Fette-Wachse, 15, p. 448 (1985).

All tests of Example 5 were carried out in a Miele brand domestic drum washing machine with about 20 l of tap water (hardness about 1 mmol/litre) at 30ºC with 125 g of standard detergent (as defined in Example 3). Each load consisted of terry towels and five additional towels, each of the additional towels being provided with four stained fabric coupons 6x6 cm as defined in Table 4. The bleach was rinsed into the wash tub together with the detergent powder. The reflectance of the test coupons was measured with a reflectometer as described in Example 4. The data in Table 4 demonstrate that the n-hexylsulfonylperoxypropionic acid of the present invention provides a bleaching effect better than or practically equal to that of DPDA. Table 4 % Reflectance No Bleach Stains* 1. Tea 2. Red Wine 3. Berries 4. Raw Cotton 5. Olive Oil/Soot *Test sections as explained in footnote to Table 3B.

Claims (9)

1. Storage-stable bleaching agent of the general structural formula in which R is a linear or branched alkyl group and n is one or more, characterized in that R contains 6 to 9 carbon atoms and n is an integer from 1 to 10 inclusive. 2. Bleaching agent according to claim 1, characterized in that the alkyl group is n-hexyl, n-octyl or n-nonyl. 3. Bleaching agent according to one of the preceding claims, characterized in that n = 2 or 3. 4. Combined bleaching agent, characterized by the use of at least two bleaching agents according to one of the preceding claims. 5. Washing, bleaching, cleaning and/or disinfectant composition, characterized by the use of a bleaching agent according to one of the preceding claims. 6. A process for the preparation of a bleaching agent according to any one of the preceding claims 1-4 by reacting a precursor carboxylic acid with an effective amount of hydrogen peroxide to form Alkylsulfonylperoxycarboxylic acid, characterized in that the reaction takes place in an acidic medium. 7. The process according to claim 6, wherein the precursor carboxylic acid is an alkylsulfonylcarboxylic acid of the following formula Alkylmercaptocarboxylic acids of the following formula or alkylsulfoxylcarboxylic acids of the following formula or a mixture thereof, wherein R and n have the meaning given in claim 1. 8. Process according to one of the preceding claims 6 and 7, in which the precursor carboxylic acid and the hydrogen peroxide are reacted in the presence of at least one further acid. 9. The process of claim 8, wherein the additional acid is methanesulfonic acid, sulfuric acid or a combination thereof.