EP4640800A1

EP4640800A1 - Aqueous composition

Info

Publication number: EP4640800A1
Application number: EP25171241.0A
Authority: EP
Inventors: Natalija Smolko Schwarzmayr
Original assignee: Nouryon Chemicals International BV
Current assignee: Nouryon Chemicals International BV
Priority date: 2024-04-26
Filing date: 2025-04-17
Publication date: 2025-10-29

Abstract

ABSTRACT OF THE DISCLOSURE

An aqueous composition includes water, a surfactant; and a hydrotrope present in an amount of at least 0.5 weight percent actives based on a total weight of the composition. The hydrotrope has the structure: wherein R is a C₆ - C₂₂ alkyl group, each of R¹ and R² is independently a C₁ - C₄ alkyl group; n is a number of from about 8 to about 25. X^- is a zwitterion having the structure: wherein each of R⁴ and R⁵ is independently H, CH₃, or (CH₂)₂COOY, wherein Y is H, Na, or K; and wherein R⁶ is H, CH₃, CH₂COOY, CH₂CH₂COOY, or (CH₂)₂N(CH₂COOY)CH₂COOY.

Description

TECHNICAL FIELD

The present disclosure generally relates to aqueous compositions that exhibit excellent cleaning ability, e.g. of hard surfaces. More particularly, this disclosure relates to aqueous compositions that include a specific hydrotrope.

BACKGROUND

The ability of an aqueous solution to spread evenly over a surface, i.e., a wetting ability, is desirable for many applications. For example, a composition for the cleaning of hard surfaces benefits from sufficient wetting of a surface. Sufficient wetting is also desirable for laundry as well as for scouring and mercerizing processes. Nonionic surfactants are known to be wetting agents, and are often present in compositions for the cleaning of hard surfaces. Most often the hard surface cleaning compositions also include alkaline components. However, many nonionic surfactants are not soluble enough in aqueous solutions, especially with a high amount of electrolytes present, such as alkali hydroxides, alkaline builders and/or complexing agents, to be usable. For this reason, many compositions that include non-ionic surfactants require the presence of a hydrotrope to improve solubility of the non-ionic surfactants. However, an effective hydrotrope is not necessarily an effective wetting agent. The primary task of a hydrotrope is to enhance the solubility of the nonionic surfactant and so increase the wetting ability of the composition. A number of hydrotropes for nonionic surfactants have been described in various publications. Examples of such hydrotropes are ethanol, sodium xylene sulphonate, sodium cumene sulphonate, alkyl glycosides, and alkoxylated quaternary ammonium compounds. However, there are drawbacks associated with each. Accordingly, there remains opportunity for improvement.

BRIEF SUMMARY

This disclosure provides an aqueous composition includes water, a surfactant; and a hydrotrope present in an amount of at least 0.5 weight percent actives based on a total weight of the composition. The hydrotrope has the structure: wherein R is a C₆ - C₂₂ alkyl group, each of R¹ and R² is independently a C₁ - C₄ alkyl group; n is a number of from about 8 to about 25. X^- is a zwitterion having the structure: wherein each of R⁴ and R⁵ is independently H, CH₃, or (CH₂)₂COOY, wherein Y is H, Na, or K; and wherein R⁶ is H, CH₃, CH₂COOY, CH₂CH₂COOY, or (CH₂)₂N(CH₂COOY)CH₂COOY.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and

FIG. 1 is a photograph of various cleaning results as described in the Examples;
FIG. 2 is a photograph of additional cleaning results as described in the Examples; and
FIG. 3 is yet another photograph of even further cleaning results as described in the Examples.

DETAILED DESCRIPTION

The following detailed description is merely exemplary in nature and is not intended to limit the current composition. Furthermore, there is no intention to be bound by any theory presented in the preceding background or the following detailed description.
Embodiments of the present disclosure are generally directed to aqueous compositions and methods for forming the same. For the sake of brevity, conventional techniques related to making polymers that may be included in such composition may not be described in detail herein. Moreover, various tasks and process steps described herein may be incorporated into a more comprehensive procedure or process having additional steps or functionality not described in detail herein. In particular, various steps in the manufacture of polymers and associated compositions are well-known and so, in the interest of brevity, many conventional steps will only be described briefly herein or will be omitted entirely without providing the well-known process details.
In this disclosure, the terminology "about" can describe values ± 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10%, in various embodiments. Moreover, it is contemplated that, in various non-limiting embodiments, it is to be appreciated that all numerical values as provided herein, save for the actual examples, are approximate values with endpoints or particular values intended to be read as "about" or "approximately" the value as recited. It is also contemplated that all isomers and chiral options for each compound described herein are hereby expressly contemplated for use herein in various non-limiting embodiments.
Throughout this disclosure, the terminology percent "actives" is well recognized in the art and means the percent amount of active or actual compound or molecule present as compared to, for example, a total weight of a diluted solution of a solvent and such a compound. Some compounds, such as a solvent, are not described relative to a percent actives because it is well known to be approximately 100% actives. Any one or more of the values described herein may be alternatively described as percent actives as would be understood by the skilled person.
In various embodiments, the terminology "free of" describes embodiments that include less than about 5, 4, 3, 2, 1, 0.5, or 0.1, weight percent (or weight percent actives) of the compound or element at issue using an appropriate weight basis as would be understood by one of skill in the art. In other embodiments, the terminology "free of" describes embodiments that have zero weight percent of the compound or element at issue.
The terminology "consists essentially of" may describe various non-limiting embodiments that are free of one or more optional compounds described herein and/or free of one or more polymers, surfactants, additives, solvents, etc.
It is to be understood that the subscripts of polymers are typically described as average values because the synthesis of polymers typically produces a distribution of various individual molecules.
The polymers and compositions disclosed herein may suitably comprise, consist of, or consist essentially of the components, elements, and process delineations described herein. The embodiments illustratively disclosed herein suitably may be practiced in the absence of any element which is not specifically disclosed herein.

Aqueous Composition

This disclosure provides an aqueous composition that includes water, a surfactant; and a hydrotrope present in an amount of at least 0.5 weight percent actives based on a total weight of the composition. The hydrotrope has the structure: wherein R is a C₆ - C₂₂ alkyl group, each of R¹ and R² is independently a C₁ - C₄ alkyl group; n is a number of from about 8 to about 25. X^- is a zwitterion having the structure: wherein each of R⁴ and R⁵ is independently H, CH₃, or (CH₂)2COOY, wherein Y is H, Na, or K; and wherein R⁶ is H, CH₃, CH₂COOY, CH₂CH₂COOY, or (CH₂)₂N(CH₂COOY)CH₂COOY.
In one embodiment, the composition is or includes the water, the surfactant, and the hydrotrope above. In another embodiment, the composition consists essentially of the water, the surfactant, and the hydrotrope. In another embodiment, the composition consists of the water, the surfactant, and the hydrotrope. The terminology "consists essentially of" describes that the composition may be free of, or include less than about 0.5, 0.4, 0.3, 0.2, or 0.1, weight percent, of one or more polymers not described herein or described herein as optional, one or more additives not described herein or described herein as optional, etc.
In other embodiments, the composition includes the water, the surfactant, and the hydrotrope and one or more additives described herein. In another embodiment, the composition consists essentially of the water, the surfactant, and the hydrotrope and one or more additives described herein. In another embodiment, the composition consists of the water, the surfactant, and the hydrotrope and one or more additives described herein. The terminology "consists essentially of" describes that the composition may be free of, or include less than about 0.5, 0.4, 0.3, 0.2, or 0.1, weight percent, of one or more polymers not described herein or described herein as optional, one or more additives not described herein or described herein as optional, etc.
In one embodiment, the composition is or includes the water, the surfactant, and the hydrotrope and is free of a chelating agent. In another embodiment, the composition consists essentially of the water, the surfactant, and the hydrotrope and is free of a chelating agent. The terminology "consists essentially of" describes that the composition may be free of, or include less than about 0.5, 0.4, 0.3, 0.2, or 0.1, weight percent, of one or more polymers not described herein or described herein as optional, one or more additives not described herein or described herein as optional, etc.

Water

The composition is aqueous and includes water. The amount of water is not particularly limited. The amount of water is typically calculated as 100 wt% - the weight percent actives of the surfactant and the hydrotrope and any chelating agent, additives, etc. In other words, the amount of water may be described as a balance, up to 100 wt%, added to the amounts of the surfactant, the hydrotrope, and any chelating agents, additives, etc.

Surfactant

The composition includes the surfactant. The surfactant is not particularly limited and may be chosen from anionic surfactants, cationic surfactants, non-ionic surfactants, zwitterionic/amphoteric surfactants, and combinations thereof.
In various embodiments, the anionic surfactant may be chosen from sodium cumene sulfonate, sodium xylene sulfonate, sodium toluene sulfonate, sodium dodecylbenzenesulfonate (SDBS), sodium lauryl sulfate (SLS), and combinations thereof.
In other embodiments, the cationic surfactant may be chosen from benzalkonium chloride, cetyltrimethylammonium bromide (CTAB), cetylpyridinium chloride (CPC), cetyltrimethylammonium chloride (CTAC), lauryl pyridinium chloride, and combinations thereof.
In other embodiments, the non-ionic surfactant may be chosen from polyoxyethylene alkyl ether, alkylglucosides, polyoxyethylene alkylamides, polyoxyethylene (20) sorbitan monooleate, polyoxyethylene (20) sorbitan monolaurate, and combinations thereof.
In other embodiments, the zwitterionic surfactant may be chosen from betaines, sulfobetaines, N-dodecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate, N-tetradecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate, N-hexadecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate, N-octadecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate, and combinations thereof.
Typically, the surfactant is a non-ionic surfactant. In various embodiments, the non-ionic surfactant is a nonionic alkylene oxide adduct, e.g. a C8-C18-alcohol alkoxylate including about 1 to about 20 ethyleneoxy units and about 0 to about 5 propyleneoxy units. For example, the adduct may have about 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, or 18 carbon atoms or about 9 to about 17, about 10 to about 16, or about 12 to about 14, carbon atoms. The adduct may have 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 ethyleneoxy units or from about 2 to about 19, about 3 to about 18, about 4 to about 17, about 5 to about 16, about 6 to about 15, about 7 to about 14, about 8 to about 13, about 9 to about 12, or about 10 to about 11 ethyleneoxy units. The adduct may have 0, 1, 2, 3, 4, or 5, or about 1 to about 4 or about 2 to about 3, propyleneoxy units. The alcohol may be linear, branched or cyclic, and may be wholly or partially saturated or unsaturated. In various non-limiting embodiments, all values and ranges of values, both whole and fractional, including and between those set forth above are hereby expressly contemplated for use herein.
In other embodiments, a combination of surfactants is utilized. For example, in various embodiments, if an amphoteric or zwitterionic surfactant is present in the composition, then the molar amount of the hydrotrope is greater than the molar amount of any anionic groups that are part of an anionic and/or amphoteric surfactant. By this is meant that the anionic groups are covalently bound within the anionic or the amphoteric surfactant; e.g. a sulphate group of an alkyl sulphate having the formula R'-OSO₃ -A+, where R' is an hydrocarbyl group with at least 6 carbon atoms, is covalently bound to the hydrocarbyl group, and these groups together constitute the anionic surfactant. Counterions are not typically taken into account in this context. In some embodiments, if any anionic and/or amphoteric surfactant is present in the composition, the molar ratio of anionic groups of the surfactant to the hydrotrope is less than 1:1, typically less than 1:2, and more typically less than 1:3. Most typically, the aqueous composition is free of anionic and amphoteric surfactants. In various non-limiting embodiments, all values and ranges of values, both whole and fractional, including and between those set forth above are hereby expressly contemplated for use herein.
In the absence of anionic and amphoteric surfactants, and if a non-ionic surfactant is present, the molar ratio between the nonionic surfactant and the hydrotrope is typically about 1:2 to about 12:1, more typically about 1:1 to about 10:1, even more typically about 1.5:1 to about 8:1, and most typically about 1.75:1 to about 7:1. If the composition is acidic, less surfactant can be used, and the molar ratio is typically 2.5:1 or higher. An acidic composition typically has a pH of 5 or less, e.g. 5, 4, 3, 2, 1, or about 0. In various non-limiting embodiments, all values and ranges of values, both whole and fractional, including and between those set forth above are hereby expressly contemplated for use herein.
In still other embodiments, the non-ionic surfactant has the following formula:

R⁷O-(PO)_x(EO)_y(PO)_zH

wherein R⁷ is a C₈ to C₁₈ alkyl group, typically C₈ to C₁₂; PO is a propyleneoxy unit, EO is an ethyleneoxy unit, x is from 0 to about 5, typically about 0 to about 4, and most typically about 0 to about 2; y is about 1 to about 20, typically about 1 to about 12, more typically about 2 to about 8, and most typically about 2 to about 5; and z is about 0 to about 5, typically about 0 to about 4, more typically about 0 to about 2, and most typically about 0. Thus, in addition to the about 1 to about 20 ethyleneoxy units, the C₈-C₁₈-alcohol alkoxylates may also include up to about 5 propyleneoxy units. In various embodiments, the number of propyleneoxy units, when present, may be as small as about 0.1 mole PO per mole alcohol. The ethyleneoxy units and the propyleneoxy units may be added randomly or in blocks. The blocks may be added to the alcohol in any order. In various non-limiting embodiments, all values and ranges of values, both whole and fractional, including and between those set forth above are hereby expressly contemplated for use herein.
In various embodiments, R⁷ has about 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, or 18 carbon atoms or about 9 to about 17, about 10 to about 16, or about 12 to about 14, carbon atoms. In other embodiments, x is 0, 1, 2, 3, 4, or 5, or about 1 to about 4 or about 2 to about 3. In other embodiments, y is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 or from about 2 to about 19, about 3 to about 18, about 4 to about 17, about 5 to about 16, about 6 to about 15, about 7 to about 14, about 8 to about 13, about 9 to about 12, or about 10 to about 11. In other embodiments, the number of propyleneoxy units is 0, 1, 2, 3, 4, or 5, or about 0 to about 4 or about 0 to about 3. In various non-limiting embodiments, all values and ranges of values, both whole and fractional, including and between those set forth above are hereby expressly contemplated for use herein.
The alkoxylates may also include an alkyl group with about 1 to about 4 carbon atoms in the end position. Typically, the alkoxylates include about 2 to about 8 ethyleneoxy units and about 0 to about 2 propyleneoxy units. The alkyl group of the nonionic surfactants may be linear or branched, saturated or unsaturated. Non-limiting examples of linear nonionic surfactants are C₉-C₁₁ alcohol+4, 5 or 6 moles of EO, C₁₁ alcohol+3, 4, 5, 6, 7 or 8 moles of EO, tridecyl alcohol+4, 5, 6, 7 or 8 moles of EO, and C₁₀-C₁₄ alcohol+8 moles of EO+2 moles of PO. Suitable branched nonionic surfactants are 2-ethylhexanol+3, 4 or 5 moles of EO, 2-ethylhexanol+2 moles of PO+4, 5 or 6 moles of EO, 2-propylheptanol+3, 4, 5 or 6 moles of EO and 2-propylheptanol+1 mole of PO+4 moles of EO. Another example is 2-butyloctanol+5, 6 or 7 moles of EO. Wherever the degree of alkoxylation is discussed, the numbers represent molar average numbers. In various non-limiting embodiments, all values and ranges of values, both whole and fractional, including and between those set forth above are hereby expressly contemplated for use herein.
In various embodiments, the surfactant is present in the composition in an amount of from about 0.05 to about 20 weight percent actives based on a total weight of the composition. In various embodiments this amount is from about 0.05 to about 1, about 0.05 to about 0.5, about 0.05 to about 0.1, about 0.1 to about 0.5, about 0.1 to about 1, about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1, weight percent actives based on a total weight of the composition. Alternatively, this amount can be from about 1 to about 20, about 2 to about 19, about 3 to about 18, about 4 to about 17, about 5 to about 16, about 6 to about 15, about 7 to about 14, about 8 to about 13, about 9 to about 12, or about 10 to about 11, weight percent actives based on a total weight of the composition. In various non-limiting embodiments, all values and ranges of values, both whole and fractional, including and between those set forth above are hereby expressly contemplated for use herein.
In other embodiments, the composition includes at least 0.05% by weight, typically at least 0.5% by weight, and at most 20% by weight, typically at most 15% by weight, and most typically at most 10% by weight, of the alcohol alkoxylate. In other embodiments, the composition includes at least 0.02% by weight, typically at least 0.1% by weight, and at most 20% by weight, typically at most 15% by weight, and most typically at most 10% by weight, of the hydrotrope. In further embodiments, the composition includes 0% by weight, typically at least 0.05% by weight, and at most 40% by weight, typically at most 30% by weight, more typically at most 20% by weight, and most typically at most 15% by weight, of alkali hydroxides, alkaline builders and/or alkaline complexing agents. In various non-limiting embodiments, all values and ranges of values, both whole and fractional, including and between those set forth above are hereby expressly contemplated for use herein. The compositions are typically excellent for use in cleaning hard surfaces, such as for vehicle cleaning and machine dishwashing.

Hydrotrope:

The hydrotrope present in an amount of at least 0.5 weight percent actives based on a total weight of the composition. In one embodiment, the hydrotrope is present in an amount of from about 0.02 to about 20 weight percent actives based on a total weight of the composition. In various embodiments this amount is from about 0.02 to about 1, about 0.02 to about 0.5, about 0.02 to about 0.1, about 0.02 to about 0.05, about 0.05 to about 0.1, about 0.1 to about 0.5, about 0.1 to about 1, about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1, weight percent actives based on a total weight of the composition. Alternatively, this amount can be from about 1 to about 20, about 2 to about 19, about 3 to about 18, about 4 to about 17, about 5 to about 16, about 6 to about 15, about 7 to about 14, about 8 to about 13, about 9 to about 12, or about 10 to about 11, weight percent actives based on a total weight of the composition. In various non-limiting embodiments, all values and ranges of values, both whole and fractional, including and between those set forth above are hereby expressly contemplated for use herein.
The hydrotrope has the structure: wherein R is a C₆ - C₂₂ alkyl group, each of R¹ and R² is independently a C₁ - C₄ alkyl group; and n is a number of from about 8 to about 25. In various non-limiting embodiments, all values and ranges of values, both whole and fractional, including and between those set forth above are hereby expressly contemplated for use herein.
In various embodiments, R has 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,1 6, 17, 18, 19, 20, 21, or 22 carbon atoms. Alternatively, R may have from about 6 to about 22, about 7 to about 21, about 8 to about 20, about 9 to about 19, about 10 to about 18, about 12 to about 16, about 12 to about 14, about 12 to about 18, about 10 to about 16, about 10 to about 14, about 10 to about 12, about 14 to about 18, or about 16 to about 18 carbon atoms. The alkyl group may be linear, branched, or cyclic and may be saturated or unsaturated. In one embodiment, R is -CH₂(CH₂)₁₀CH₃. In another embodiment, R is -CH₂(CH₂)_10-12CH₃. In various non-limiting embodiments, all values and ranges of values, both whole and fractional, including and between those set forth above are hereby expressly contemplated for use herein.
In other embodiments, each of each of R¹ and R² is independently has 1, 2, 3, or 4 carbon atoms and may be linear, branched, or cyclic and may be saturated or unsaturated. In one embodiment, each of R¹ and R² is methyl. In various non-limiting embodiments, all values and ranges of values, both whole and fractional, including and between those set forth above are hereby expressly contemplated for use herein.
Moreover, n can be 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24 or 25. In various embodiments, n can be about 8 to about 25, about 9 to about 24, about 10 to about 23, about 11 to about 22, about 12 to about 21, about 13 to about 20, about 14 to about 19, about 15 to about 18, or about 16 to about 17. In other embodiments, n is from about 10 to about 17. In various non-limiting embodiments, all values and ranges of values, both whole and fractional, including and between those set forth above are hereby expressly contemplated for use herein.
In one embodiment, n is 13, R is C₁₂-C₁₄, and R¹ and R² are both CH₃.
Referring back, X^- is a zwitterion having the structure: wherein each of R⁴ and R⁵ is independently H, CH₃, or (CH₂)₂COOY, wherein Y is H, Na, or K; and wherein R⁶ is H, CH₃, CH₂COOY, CH₂CH₂COOY, or (CH₂)₂N(CH₂COOY)CH₂COOY.
In one embodiment, each of R⁴, R⁵, and R⁶, is H. In this embodiment, the hydrotrope may alternatively be described as a glycine salt.
In another embodiment, R⁴ is CH₂CH₂COOY and both of R⁵ and R⁶ are CH₂COOY. In this embodiment, the hydrotrope may alternatively be described as a GLDA salt.
In another embodiment, R⁴ is H, R⁵ is (CH₂)₂N(CH₂COOY)CH₂COOY, and R⁶ is CH₂COOY. In this embodiment, the hydrotrope may alternatively be described as an EDTA salt.
In another embodiment, R⁴ is CH₃ and each of R⁵ and R⁶ is H. In this embodiment, the hydrotrope may alternatively be described as an alanine salt.
In another embodiment, R⁴ is CH₃ and each of R⁵ and R⁶ is CH₂COOY. In this embodiment, the hydrotrope may alternatively be described as an MGDA salt.
In another embodiment, R⁴ is H, R⁵ is CH₃, and R⁶ is H. In this embodiment, the hydrotrope may alternatively be described as a sarcosine salt.
In various embodiments, one or more of these salts may be utilized. Moreover, all combinations of the above are hereby expressly contemplated for use in non-limiting embodiments.

Chelating Agent

The composition may include, or be free of, a chelating agent. The chelating agent is not particularly limited and may be any known in the art. For example, the chelating agent may be chosen from ethylenediaminetetraacetic acid (EDTA), citric acid, diethylene triamine pentaacetic acid (DTPA), nitrilotriacetic acid (NTA), hydroxyethyl ethylenediaminetriacetic acid (HEDTA), ethylene glycol tetraacetic acid (EGTA), trisodium citrate, sodium gluconate, a phosphonic acid (e.g., HEDP, ATMP, etc.), a polyaminocarboxylic acids (e.g., PCA, etc.), methylglycinediacetic acid (MGDA), glutamic acid diacetate (GLDA), and combinations thereof. In other embodiments, the chelating agent is chosen from EDTA, GLDA, MGDA, and combinations thereof.
If used, the chelating agent may be present in an amount of from about 0.1 to about 50 weight percent actives based on a total weight of the composition. In various embodiments, the amount is from about 0.1 to about 10, about 2 to about 9, about 3 to about 8, about 4 to about 7, about 5 to about 6, about 5 to about 50, about 10 to about 40, about 15 to about 35, about 20 to about 30, or about 25 to about 35, weight percent actives based on a total weight of the composition. In other embodiments, the weight is about 4 to about 20, about 6 to about 18, about 8 to about 16, about 10 to about 14, or about 10 to about 12, weight percent actives based on a total weight of the composition. In other embodiments, it is contemplated that the composition is free of the chelating agent (e.g. zero weight percent) or includes less than 1, 0.5, or 0.1 weight percent actives of the chelating agent based on a total weight of the composition. In various non-limiting embodiments, all values and ranges of values, both whole and fractional, including and between those set forth above are hereby expressly contemplated for use herein.

Additives

The composition may be acidic, neutral or alkaline. Accordingly, the composition may include, or be free of, one or more additives, such as those that would be used to form acidic, neutral, or alkaline compositions. For example, the composition may include, or be free of, alkali hydroxides, alkaline builders and/or complexing agents. The alkali hydroxides typically are sodium or potassium hydroxide. The alkaline builders may be an alkali carbonate or an alkali hydrogen carbonate, such as sodium carbonate, potassium carbonate, sodium hydrogen carbonate or potassium hydrogen carbonate, an alkali salt of a silicate, such as sodium silicate or sodium metasilicate, or alkali salts of phosphates, such as sodium orthophosphate. Alkaline builders which act through complexation are, e.g., sodium pyrophosphate and sodium tripolyphosphate and the corresponding potassium salts. The builder/complexing agent may also be organic. Examples of organic builders/complexing agents are aminocarboxylates, such as sodium nitrilotriacetate (Na₃NTA), sodium diethylenetriamine pentaacetate, sodium 1,3-propylenediamine tetraacetate, and sodiumhydroxyethylethylenediamine triacetate; aminopolyphosphonates, such as nitrilotrimethylene phosphonate; organic phosphates; polycarboxylates, such as citrates; and alkali salts of gluconic acid, such as sodium or potassium gluconates. In neutral and acidic compositions complexing agents may also be added, such as citric acid.
In various non-limiting embodiments, one or more of the components, methods, techniques, etc. described herein may be as described in WO2006079598A1 , which is expressly incorporated herein by reference in its entirety.

Method of Making:

A compound representative of the hydrotrope described above can be prepared in the following way, wherein the term "bar a" means the absolute pressure.

Ethoxylation Reaction

To 265.2 g (1.27 moles) of monomethyl mono-(C₁₂-C₁₄-alkyl)amine, heated at 170° C. in a stainless steel autoclave that had been evacuated, 57.0 g (1.27 moles) of ethylene oxide were added with stirring during a period of 40 minutes. The temperature was kept at 170° C. during the addition, and the maximal pressure was 4.5 bar a. After the addition, the reaction mixture was kept at this temperature for 1 h. Then the temperature was lowered to 100° C., and 0.8 g KOH dissolved in methanol was added. The methanol and water were evaporated off at approximately 0.2 bar a at a temperature of 100-170° C., after which ethylene oxide was added at 170° C. in the appropriate amount to obtain the desired degree of ethoxylation. The maximal pressure during the addition was 4.5 bar a, and after the addition the reaction mixture was kept at this temperature until a steady pressure was obtained.

Quaternization Reaction

The ethoxylated product obtained in the previous step was heated to 85-90° C. and an equimolar amount of methyl chloride was added with stirring over 5-10 minutes. The reaction was exothermic, and the temperature rose to 105-110° C. The maximal pressure during the reaction was 3.0-3.2 bar a. After about 15 minutes the pressure was 1 bar a at 110° C., and the stirring and heating was continued for 1 h.
This example describes the ethoxylation and quaternization of monomethyl mono-(C₁₂-C₁₄-alkyl)amine. The equivalent process may generally be used for the synthesis of all of the cationic hydrotropes of the present disclosure. This is just a suitable example of a process for making these compounds; they may also be obtained by a number of other processes.
Subsequently, the above product may be exposed to an ion-exchange resin, or any other suitable compound or method, to remove the chlorine ion. Then, desirable salts can be formed by reacting the de-chlorinated compound with an amino acid, or any similar suitable compound, to form the desired salt, using any method known in the art.

Method of Using

This disclosure also provides a method of using the hydrotrope. The hydrotrope may be used in any application, e.g. in cleaning compositions for hard surfaces. In one embodiment, the disclosure provides for use of a hydrotrope in an aqueous solution comprising a non-ionic surfactant, wherein the hydrotrope has the following formula: wherein R is a C₆ - C₂₂ alkyl group, each of R¹ and R² is independently a C₁ - C₄ alkyl group; n is a number of from about 8 to about 25; and X^- is a zwitterion; and wherein the non-ionic surfactant is a nonionic alkylene oxide adduct. Notably, X^- may be any described herein. Alternatively, X^- may be of a type not described herein. Moreover, the non-ionic surfactant may be any described herein or any known in the art. In another embodiment, this disclosure provides use of a cationic surfactant having the aforementioned formula wherein R is a C₆ - C₂₂ alkyl; each of R¹ and R² is independently a C₁ - C₄ alkyl group; n is 8-25; and X^- is an zwitterion, as a hydrotrope for a nonionic surfactant, typically nonionic alkylene oxide adducts, more typically a C8-C18-alcohol alkoxylate that includes 1-20 ethyleneoxy units and 0-5 propyleneoxy units, in aqueous solutions.

EXAMPLES

Ion Exchange:

250 g of Compound A (below) and 170 g of deionized water are combined. 350 ml of the ion-exchange resin known as Lewatit S6268 is decanted and added thereto and mixed for 30 min at RT. This produces a chloride free version of Compound A which is herein referred to as Compound B, also below. Compound B was filtered from Lewatit S6268 using fiber towel mounted on a funnel. About 380 ml of Compound B was collected.
The efficiency of ion exchange process was determined by evaluation of an amount of inorganic chloride by a common titration method before and after the ion exchange procedure. It was found that the amount of chloride was reduced from 2.5% to undetectable. It was also found that amount of water increased in the product after ion exchange from 39% to 46%.
After ion-exchange, 10 g of Compound B was added to a 20 ml glass bottle with a crew-cup. 1.01 moles of various amino acids were then added to various samples of the above. These were: glycine, sarcosine, alanine, GLDA and EDTA. The content of the glass bottles was homogenized. This produced various salts of Compound B.
2 g of the salts of Compound B, or 2 grams of Compound A, or 2 grams of a 1:1 weight mixture of Compound A and a salt of Compound B, were then combined with 2 g of Decanol + 4EO and 46 g of demineralized water and homogenized to form various solutions. The pH of the solutions was adjusted to 10.5 by the use of 5%aq NaOH solution or 8% aq. acetic acid solution.

Cleaning Test

White painted metal plates were smeared with an oil-soot mixture obtained from train diesel engines. 10 ml of each of the aforementioned solutions were poured through a glass funnel onto the oil-smeared plates and left to rest for 30 sec. Then, the plates were rinsed with a rich flow of water. All solutions and the water were kept at a temperature of about 18-22°C.
The cleaning results are set forth visually in Figures 1-3.
Composition 1 is the glycine salt of Compound B wherein each of R⁴, R⁵, and R⁶, is H.
Reference is Compound A.
Composition 7 is the GLDA salt of Compound B wherein R⁴ is CH₂CH₂COOY and both of R⁵ and R⁶ are CH₂COOY.
Composition 8 is the EDTA salt of Compound B wherein R⁴ is H, R⁵ is (CH₂)₂N(CH₂COOY)CH₂COOY, and R⁶ is CH₂COOY.
Composition 3 is the sarcosine salt of Compound B wherein R⁴ is H, R⁵ is CH₃, and R⁶ is H.
Composition 5 is the alanine salt of Compound B wherein R⁴ is CH₃ and each of R⁵ and R⁶ is H.
Composition Reference/7 is a 1:1 weight mixture of Compound A and the GLDA salt of Compound B wherein R⁴ is CH₂CH₂COOY and both of R⁵ and R⁶ are CH₂COOY.
The results, as shown in Figures 1-3, clearly demonstrate that in all cases addition of the salts of Compound B dramatically improved cleaning performance of the cleaning formulations. These results are superior to the use of Compound A alone and are also unexpected to those of skill in the art.
While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing an exemplary embodiment. It being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope as set forth in the appended claims.
The present disclosure may be further described by the following Aspects.

Aspect 1. An aqueous composition comprising:
1. A. water;
2. B. a surfactant; and
3. C. a hydrotrope present in an amount of at least 0.5 weight percent actives based on a total weight of the composition and having the structure:
  - wherein R is a C₆ - C₂₂ alkyl group, each of R¹ and R² is independently a C₁ - C₄ alkyl group; n is a number of from about 8 to about 25; and X^- is a zwitterion having the structure:
  - wherein each of R⁴ and R⁵ is independently H, CH₃, or (CH₂)₂COOY, wherein Y is H, Na, or K; and
  - wherein R⁶ is H, CH₃, CH₂COOY, CH₂CH₂COOY, or (CH₂)₂N(CH₂COOY)CH₂COOY. Aspect 2. The composition of Aspect 1 wherein each of R⁴, R⁵, and R⁶, is H.
Aspect 3. The composition of Aspect 1 wherein R⁴ is CH₂CH₂COOY and both of R⁵ and R⁶ are CH₂COOY.
Aspect 4. The composition of Aspect 1 wherein R⁴ is H, R⁵ is (CH₂)₂N(CH₂COOY)CH₂COOY, and R⁶ is CH₂COOY.
Aspect 5. The composition of Aspect 1 wherein R⁴ is CH₃ and each of R⁵ and R⁶ is H.
Aspect 6. The composition of Aspect 1 wherein R⁴ is CH₃ and each of R⁵ and R⁶ is CH₂COOY.
Aspect 7. The composition of Aspect 1 wherein R⁴ is H, R⁵ is CH₃, and R⁶ is H.
Aspect 8. The composition of any preceding Aspect wherein R¹ and R² are methyl.
Aspect 9. The composition of any preceding Aspect wherein n is from about 10 to about 17.
Aspect 10. The composition of any preceding Aspect wherein R is CH₂(CH₂)_10-12CH₃.
Aspect 11. The composition of any preceding Aspect wherein the surfactant is present in an amount of from about 0.05 to about 20 weight percent actives based on a total weight of the composition.
Aspect 12. The composition of any preceding Aspect wherein the hydrotrope is present in an amount of from about 0.02 to about 20 weight percent actives based on a total weight of the composition.
Aspect 13. The composition of any preceding Aspect wherein the surfactant comprises a C₈-C₁₈-alcohol alkoxylate comprising from about 1 to about 20 ethyleneoxy units and from about 0 to about 5 propyleneoxy units.
Aspect 14. The composition of Aspect 13 wherein the alcohol alkoxylate has the formula:

R⁷O-(PO)_x(EO)_y(PO)_zH

wherein R⁷ is a C₈ to C₁₈ alkyl group, PO is a propyleneoxy unit, EO is an ethyleneoxy unit, x is from about 0 to about 4, y is from about 1 to about 20, and z is from about 0 to about 4.
Aspect 15. The composition of any preceding Aspect wherein the molar amount of the hydrotrope is greater than the molar amount of the surfactant.
Aspect 16. The composition of any preceding Aspect that is free of anionic and amphoteric surfactants.
Aspect 17. The composition of any preceding Aspect further comprising an alkali hydroxide, an alkaline builder, and/or an alkaline complexing agent.
Aspect 18. The composition of any preceding Aspect wherein the surfactant is present in an amount of from about 0.05 to about 20 weight percent actives based on a total weight of the composition and the hydrotrope is present in an amount of from about 0.02 to about 20 weight percent actives based on a total weight of the composition.
Aspect 19. The composition of any preceding Aspect that is free of a chelating agent.
Aspect 20. The composition of any preceding Aspect consisting essentially of (A)-(C).
Aspect 21. Use of a hydrotrope in an aqueous solution comprising a non-ionic surfactant, wherein the hydrotrope has the following formula:
- wherein R is a C₆ - C₂₂ alkyl group, each of R¹ and R² is independently a C₁ - C₄ alkyl group; n is a number of from about 8 to about 25; and X^- is a zwitterion; and
- wherein the non-ionic surfactant is a nonionic alkylene oxide adduct.

Claims

An aqueous composition comprising:
A. water;

B. a surfactant; and

C. a hydrotrope present in an amount of at least 0.5 weight percent actives based on a total weight of the composition and having the structure:

wherein R is a C₆ - C₂₂ alkyl group, each of R¹ and R² is independently a C₁ - C₄ alkyl group; n is a number of from about 8 to about 25; and X^- is a zwitterion having the structure:

wherein each of R⁴ and R⁵ is independently H, CH₃, or (CH₂)₂COOY, wherein Y is H, Na, or K; and

wherein R⁶ is H, CH₃, CH₂COOY, CH₂CH₂COOY, or (CH₂)₂N(CH₂COOY)CH₂COOY.
The composition of claim 1 wherein each of R⁴, R⁵, and R⁶, is H; or
wherein R⁴ is CH₂CH₂COOY and both of R⁵ and R⁶ are CH₂COOY; or

wherein R⁴ is H, R⁵ is (CH₂)₂N(CH₂COOY)CH₂COOY, and R⁶ is CH₂COOY, or

wherein R⁴ is CH₃ and each of R⁵ and R⁶ is H; or

wherein R⁴ is CH₃ and each of R⁵ and R⁶ is CH₂COOY, or

wherein R⁴ is H, R⁵ is CH₃, and R⁶ is H.
The composition of claims 1 or 2 wherein R¹ and R² are methyl.
The composition of any preceding claim wherein n is from about 10 to about 17.
The composition of any preceding claim wherein R is CH₂(CH₂)_10-12CH₃.
The composition of any preceding claim wherein the surfactant is present in an amount of from about 0.05 to about 20 weight percent actives based on a total weight of the composition, and/or wherein the hydrotrope is present in an amount of from about 0.02 to about 20 weight percent actives based on a total weight of the composition.
The composition of any preceding claim wherein the surfactant comprises a C₈-C₁₈-alcohol alkoxylate comprising from about 1 to about 20 ethyleneoxy units and from about 0 to about 5 propyleneoxy units.
The composition of claim 7 wherein the alcohol alkoxylate has the formula:

R⁷O-(PO)_x(EO)_y(PO)_zH

wherein R⁷ is a C₈ to C₁₈ alkyl group, PO is a propyleneoxy unit, EO is an ethyleneoxy unit, x is from about 0 to about 4, y is from about 1 to about 20, and z is from about 0 to about 4.
The composition of any preceding claim wherein the molar amount of the hydrotrope is greater than the molar amount of the surfactant.
The composition of any preceding claim that is free of anionic and amphoteric surfactants.
The composition of any preceding claim further comprising an alkali hydroxide, an alkaline builder, and/or an alkaline complexing agent.
The composition of any preceding claim wherein the surfactant is present in an amount of from about 0.05 to about 20 weight percent actives based on a total weight of the composition and the hydrotrope is present in an amount of from about 0.02 to about 20 weight percent actives based on a total weight of the composition.
The composition of any preceding claim that is free of a chelating agent.
The composition of any preceding claim consisting essentially of (A)-(C).
Use of a hydrotrope in an aqueous solution comprising a non-ionic surfactant, wherein the hydrotrope has the following formula:
wherein R is a C₆ - C₂₂ alkyl group, each of R¹ and R² is independently a C₁ - C₄ alkyl group; n is a number of from about 8 to about 25; and X^- is a zwitterion; and

wherein the non-ionic surfactant is a nonionic alkylene oxide adduct.