MXPA99011179A - Process for making solid amine oxide surfactant composition - Google Patents

Abstract

The present invention is directed to solid amine oxide compositions which are useful in formulating detergent products, such as laundry detergents, shampoos, personal cleansing compositions, and cosmetic compositions, especially solid or granular cleaning products. These solid compositions consist of (a) amine oxide and (b) complexing acid. The complexing acid is defined as a saturated or unsaturated carboxylic acid with at least 5 carbon atoms, phosphonic acid, and mixtures thereof.

Description

PROCEDURE FOR PREPARING A SOLID COMPOSITION OF AMINO OXIDE SURGICAL AGENT FIELD OF THE INVENTION The present invention relates to a process for preparing solid compositions containing amine oxide-acid salts. Said solid compositions are a source of concentrated amine oxide surfactants for incorporation into cleaning products, especially solid or granular cleaning products.

BACKGROUND OF THE INVENTION Amine oxides are commonly used in cleaning compositions to increase and maintain foam formation. Such compositions include, for example, laundry compositions, shampoos and dishwashing detergent compositions. Many methods are known for preparing amine oxide surfactants from a corresponding tertiary amine. Such methods include the conversion of a tertiary amine in the presence of a strong oxidizing agent to the corresponding amine oxide. For example, tertiary amines can react with hydrogen peroxide to produce 30-40% aqueous solution of the corresponding amine oxide. Catalysts are commonly used to facilitate the reaction. Most of these methods, however, result in liquid formulations containing the amine oxide. For economy in shipping and for use in solid or granular detergent compositions, solid amine oxide surfactant formulations are more preferred than typical commercially available amine oxide surfactant formulations in liquid form , in gels, or in paste. Many attempts have been made to prepare amine oxide surfactants in solid or granular formulations. The patent of E.U.A. 5,399,296, issued March 21, 1995 to Wierenga et al. and the patent of E.U.A. 5,389,306 issued February 14, 1995 to Wierenga et al. describe solid amine oxide compositions containing maleic acid-amine oxide salts and the process for making said compositions. The above considerations involving amine oxide surfactant formulations and the processes for preparing them indicate that there is a continuing need to provide solid formulations containing amine oxide surfactants. None of the existing techniques provide all the advantages and benefits of the present invention. It has been found that in addition to the solid amine oxide compositions containing maleic acid-amine oxide salts, other solid compositions of amine oxide surfactant can be formed. Said solid compositions of amine oxide surfactant can be used as a source of amine oxide surfactants in cleaning compositions.

BRIEF DESCRIPTION OF THE INVENTION The present invention is directed to a process for preparing solid amine oxide surfactant compositions which are useful for formulating detergent products, such as laundry detergents, shampoos, personal cleansing compositions, and cosmetic compositions, especially solid cleaning products. or granulates. The process comprises mixing the complexing acid with an amine oxide surfactant formulation by mixing 1 mole of complexing acid with X mole (s) of amine oxide, where X is from about 1 to about equal to the number of acid groups of the acid that forms complex. The pH of the mixture is from about 1 to about 3, whereby a visible precipitate forms in the mixture. The formed precipitate is separated from the mixture, preferably by mechanical means, and allowed to dry. The separated precipitate forms the solid compositions of the present invention, which solid compositions consist of amine oxide and complex forming acid as described above.

These and other features, aspects, and advantages of the present invention will be apparent to those skilled in the art upon reading the present disclosure.

DETAILED DESCRIPTION OF THE INVENTION Although this specification concludes with claims that are indicated in a different manner and specifically claim what is considered as the invention, it is believed that the invention can be understood by carefully reading the following detailed description of the invention. All percentages, ratios and proportions are in weight, all temperatures are expressed in degrees centigrade, molecular weights are in average weight, and decimal is represented by the point (.), Unless otherwise indicated way. All relationships are weight ratios unless specifically stated otherwise. As used herein, "comprises" means that other steps and other ingredients may be added that do not affect the final result. This term encompasses the terms "consists of" and "consists essentially of". As used herein, the term "solid compositions" refers to solids composed of particles (eg, powders, granules, agglomerates) and solids not composed of particles.

As used herein, all pKa and pH values are measured in water at 25 ° C. All cited references are incorporated herein by reference in their entirety. The appointment should not be considered as any determination as to its availability as a prior art to the claimed invention. The process for preparing the solid compositions of the amine oxide surfactant of the present invention, which includes preferred embodiments thereof, is described in detail below.

Amine oxide formulations The amine oxide formulations for use in the present process comprise varying amounts of amine oxide surfactants. Said amine oxide formulations, and the processes for preparing them, are well known in the surfactant art. The amine oxide formulations for use in the present process comprise varying percentages of the amine oxide surfactant. Amine oxide surfactants are commercially available in many physical forms, including liquid, paste, gel and solid. The percentage of the amine oxide surfactant in the formulation, as well as the type of said amine oxide surfactant, is not critical to the successful operation of the present process. Also, any known or conventional amine oxide formulation can be used. Such known or conventional formulations typically contain from about 3% to about 80%, very typically from about 5% to about 20%, most preferably from about 5% to about 10% by weight of the amine oxide surfactant in a solution of diluted water. However, it is understood that formulations containing high and low concentrations of amine oxide surfactant can also be used in the present process. The amine oxide surfactants for use in the present process preferably have the formula RR'R "NO, wherein R is an unsubstituted alkyl or alkenyl group containing from about 6 to about 30, preferably from about 8 to 18 carbon atoms The groups R 'and R "each are substituted or unsubstituted alkyl or alkenyl groups containing from about 1 to about 18, preferably from about 1 to about 4, carbon atoms. Most preferably, R1 and R "are each methyl groups, examples of which include dodecyl dimethylamine oxide, tetradecyldimethylamine oxide, hexadecyldimethylamine oxide, octadecyldimethylamine oxide, and cocoalkyldimethylamine oxides. Examples of amine oxide surfactants suitable for use in the present process include, but are not limited to, dodecyldimethylamine oxide, tridecyldimethylamine oxide, tetradecyldimethylamine oxide, pentadecyldimethylamine oxide, hexadecyldimethylamine oxide, heptadecyldimethylamine oxide, octadecyldimethylamine oxide, dodecyldiethyl amine oxide, tetradecyldimethylamine oxide, hexadecyldiethyl amine octadecyldiethyl amine oxide, dodecyldipropylamine oxide, tetradecylpropylamine oxide, hexadecylpropylamine oxide, octadecyldipropylamine oxide, dodecyldibutylamine oxide, tetradecyldibutylamine oxide, hexadecyldibutylamine oxide, octadecyldibutylamine oxide, dodecylmethylethylamine oxide , tetradecylethylpropylamine oxide, hexadecylpropylbutylamine oxide, and octadecylmethylbutylamine oxide. Other preferred amine oxides are ADMOX ™, which is an amine oxide of C? dihydrate. ADMOX ™ and other amine oxides useful in the process herein are set forth in the patent E.U.A. No. 5,292,955 (Smith and Sauer, issued March 8, 1994). Also useful are the amine oxide surfactants made by oxidation of the tertiary amines prepared from mixed alcohols obtained from coconut oil. Said cocoalkylamine oxides are economically preferred since it is not necessary to separate the mixed alcohol fractions in their pure components to ensure the pure chain length fractions of the amine oxides for the purposes of the present formulations. of amine oxide for use in the process herein can be prepared by known and conventional methods. Such methods typically include the controlled oxidation of the tertiary amines to the corresponding amine oxide using a strong oxidizing agent. A preferred oxidizing agent is hydrogen peroxide. A solution of dilute hydrogen peroxide, or preferably concentrated (30 wt% or more), is added in a stoichiometric amount or greater to a liquid solution containing the tertiary amine for conversion thereof to the amine oxide. The reaction rates and yields of amine oxide can be improved by the incorporation of catalysts and / or chelating agents known in the surfactant art for this particular application. Methods for making amine oxide surfactants are described, for example, in the U.S.A. 3,215, 741 (Chadwick, issued November 2, 1965), the patent of E.U.A. 3,223,647 (Drew and Voss, issued December 14, 1965), British patent 437,566 (issued October 31, 1935), and the US patent. 4,565,891 (Correa and Riley, issued July 19, 1984).

Acid to form complex The process for preparing the solid compositions of the present invention was carried out by mixing a complexing acid with an amine oxide formulation described hereinabove. The acid that forms complex is defined as a carboxylic acid saturated with at least 5 carbon atoms, unsaturated carboxylic acid with at least 5 carbon atoms, phosphonic acid, and mixtures thereof. Such complexing acids will effectively precipitate the amine oxide surfactants from the amine oxide formulations. As used herein, the term "carboxylates" generally means carboxyl-containing compounds. The complex forming acids of the present invention may be in powder form, or in an aqueous solution, although the physical form of the complexing acid is not critical to the invention. The acid that forms complex is soluble in water at a temperature less than about 35 ° C. Examples of saturated and unsaturated carboxylic acids with at least 5 carbon atoms include citric acid, polyacrylic acid, malonic acid, adipic acid, oxalic acid, glutaric acid, phthalic acid, lauric acid, oleic acid, benzoic acid, and butyric acid. Examples of phosphonic acids include tetrasodium pyrophosphate (TSPP), sodium tripolyphosphate (STPP), diethylenetriaminepentamethylphosphonic acid, hydroxyethanediphosphonic acid, and ethylenediaminetetramethylenephosphonic acid. Preferred polyacrylic acids have a molecular weight scale of about 2,500 to 70,000, preferably a molecular weight scale of about 10,000 to about 50,000.

The water-soluble salts of the complexing acid can also be used in the present process. Said salts may comprise alkali metals (eg, sodium, potassium), alkaline earth metals, ammonium, substituted ammonium, and so forth. Among such salts, sodium citrate, diammonium citrate, sodium tripolyphosphate and sodium pyrophosphate are preferred. Other water-soluble salts can be used in the present process since said salts are compatible with the amine oxide surfactant selected for use herein. An essential step in the present process is to add the complexing acid in amounts necessary for the amine oxide formulation to form a solid composition of amine oxide surfactant. It is preferred that the amine oxide can be diluted in a water solution, having an active level of from about 3% to about 80%, preferably from about 5% to about 20%, most preferably from about 5% to about 10% Normally, the pH adjustment of the amine oxide formulation is needed to the necessary level, from about 1 to about 3, when the acid forming complex is used in the present process. The precipitation of the desired amine oxide salt will not occur to a certain degree until such pH values of the mixture are achieved. The complex is formed by mixing 1 mole of complexing acid with X mole (s) of amine oxide, where X is from about 1 to about equal to the number of acid groups of the acid forming compound. X should be within about plus or minus 25%, preferably about plus or minus 10%, of the number of acid groups in the acid that forms complex. The pH of the mixture is from about 1 to about 3, where a visible precipitate forms in the mixture. The formed precipitate is separated from the mixture, preferably by mechanical means, and allowed to dry. The process of the present invention is described herein in terms of the addition of the complexing acid to an amine oxide formulation. However, it is understood that any reference, herein, to the acid forming complex, implicitly includes salts of complexing acids (described hereinbefore), complex forming acids which are acids and mixtures thereof.

Processes The process of the present invention comprises mixing the complex forming acid and an amine oxide formulation to form a visible precipitate therein, and subsequently separating the formed precipitate from the mixture. The procedure is described in detail below. In a first step of the process, 1 mole of a complexing acid and X moles of an amine oxide formulation described herein (10% active composition in a diluted solution of water) are mixed, where X is found about 1 approximately equal to the number of acid groups of the acid that forms complex. The pH of the mixture is about 1 about 3, where a visible precipitate forms in the mixture. The formed precipitate which was made in accordance with the process of the present invention is a salt of the complexing amine oxide and acidic surfactant. In a preferred method, an excess of acid that forms complex is used to accelerate the formation of the precipitate. An excess of 30% complexing acid is preferred above the molar amount described above. In a second step of the present process, the formed precipitate is separated from the mixture. Preferably, said separation is carried out by mechanical means such as projection, filtering, centrifugation and the like. The separated precipitate can then be washed with cold water (pH adjusted around the pKa of the amine oxide) to remove non-precipitated reagents and subsequently dried to form a solid formulation. Preferably, significantly all the impurities have been removed from the water before washing. The solid formulation can be reduced to fine, agglomerated particles, and so on. Since the precipitate can be separated by mechanical means, there is no need to use organic extraction solvents to perform said separations. However, it is understood that organic extraction solvents can be used in the present process, but that their use is not preferred or necessary. The hydration water of the complex formed will vary depending on the drying operation used, for example, air drying, forced air drying, hot air drying by convection, drying / washing with organic solvent, and so on.

EXAMPLES It is understood that the examples and embodiments described herein are for illustrative purposes only and various modifications or changes in light are suggested to those skilled in the art, without departing from the scope of the present invention.

EXAMPLE 1 Approximately 0.92 grams of citric acid complexing acid are mixed with about 30 grams of amine oxide solution (C14 alkyldimethylamine oxide, 10% active composition in a water solution). The molar ratio of the acid that forms complex to an active amine oxide is about 1: 2. The pH of the mixture of the amine oxide solution in citric acid is about 1 to about 3. The pH is adjusted with the addition of an excess of citric acid. A visible precipitate forms almost immediately. The mixture is allowed to stand for 5 minutes. Subsequently the precipitate is filtered from the mixture, washed with water (pH of 7), in which the water has substantially all the impurities removed, and dried with air before it is reduced to a fine powder. The citric acid is preferably in powder form.

EXAMPLE 2 The procedure described in Example 1 is repeated, except that 30 grams of C 16 alkyldimethylamine oxide (7.85% solution) are mixed with a solution of 0.76 grams of citric acid, thereby forming a precipitate. After adding the initial citric acid and after the precipitate formed, 0.40 grams of additional citric acid is added to adjust the viscosity. The molar ratio of the acid that forms complex to the active amine oxide is 1: 1.5.

EXAMPLE 3 The procedure described in Example 1 is repeated, except that 5.27 grams of C 16 alkyldimethylamine (6.4% solution) are mixed with a solution of 0.09 grams of citric acid. The molar ratio of the acid that forms complex to an active amine oxide is 1: 3, and the pH of the C16 alkyldimethylamine oxide solution is adjusted using 1 N HCl at a pH of 0.97, before the addition of citric acid .

EXAMPLE 4 The procedure described in Example 1 is repeated, except that 365 grams of C 14 alkyldimethylamine oxide (10% solution) are mixed with 0.34 grams of acid that forms STPP complex (98% active composition). The molar ratio of the complexing acid to the active amine oxide is 1: 5, and the pH is adjusted using 1 N HCl at a pH of 1.26 before the addition of STPP.

EXAMPLE 5 The procedure described in Example 1 is repeated, except that 20 grams of C 14 alkyldimethylamine oxide (10% solution) are mixed with 4.31 grams of diethylenetriaminepentamethylphosphonic acid (25% active solution). The molar ratio of the complexing acid to the active amine oxide is 1: 5, and the pH is adjusted using 1 N HCl to a pH of 1.0 before the addition of the complexing acid.

EXAMPLE 6 The procedure described in Example 1 is repeated, except that 47 grams of C 14 alkyldimethylamine oxide (9.8% solution) are mixed with 9.35 grams of complex forming acid (48% active composition) of polyacrylic acid (molecular weight 4,500) ). The molar ratio of the acid that forms complex to the active amine oxide is 1: 24. No pH adjustment is necessary before the addition of polyacrylic acid.

Claims (8)

NOVELTY OF THE INVENTION CLAIMS

1. - A process for preparing solid compositions of amine oxide surfactant, which process comprises the steps of: a) mixing a complex forming acid and an amine oxide, (i) wherein the molar ratio of the acid complexing to the Amine oxide is 1: X, wherein X is about 1 to about equal to the number of acid groups of the acid that forms complex; and (ii) wherein the acid forming complex is selected from a group consisting of carboxylic acid saturated with at least 5 carbon atoms, unsaturated carboxylic acid with at least 5 carbon atoms, phosphonic acid and mixtures thereof. same; and b) separating the precipitate from the mixture to form from the separated precipitate a solid amine oxide surfactant composition containing an amine oxide complex-forming acid salt.

2. The process according to claim 1, further characterized in that the complex forming acid is selected from a group consisting of citric acid, polyacrylic acid, malonic acid, adipic acid, oxalic acid, glutaric acid, phthalic acid, acid lauric, oleic acid, benzoic acid, and butyric acid, tetrasodium pyrophosphate (TSPP), sodium tripolyphosphate (STPP), diethylenetriaminepentamethylphosphonic acid, hydroxyethanediphosphonic acid, ethylenediaminetetramethylenephosphonic acid, and mixtures thereof.

3. The process according to claim 1, further characterized in that the amine oxide has the formula RR'R "NO, wherein R is a substituted or unsubstituted alkyl or alkenyl group containing from about 6 to about 30. carbon atoms and the groups R 'and R "are each substituted or unsubstituted alkyl or alkenyl groups containing from about 1 to about 18 carbon atoms.

4. The process according to claim 1, further characterized in that the precipitate is separated from the mixture by mechanical means and allowed to dry.

5. The process according to claim 2, further characterized in that the polyacrylic acid has a molecular weight of about 2,500 to about 70,000.

6. The process according to claim 3, further characterized in that the amine oxide has an active level of about 3% to about 80%.

7. The process according to claim 3, further characterized in that the R group in the amine oxide contains from about 8 to about 18 carbon atoms, and the R 'and R "each contain about 1 to about 4 carbon atoms.

8. - The method according to claim 7, further characterized in that R "and R" are each methyl groups.