MXPA01002118A - Solubilization of low 2-phenyl alkylbenzene sulfonates - Google Patents

Abstract

Methods and compositions relating to solubilization of alkylbenzene sulfonate surfactants in detergent formulations. Addition of one or more ethylene oxide/propylene oxide block copolymers to detergents including alkylbenzene sulfonate surfactants may be used to increase solubility of the alkylbenzene sulfonate surfactants. Increased solubility of the alkyl benzene sulfonate surfactants serves to lower the cloud point of the detergents permitting, for example, the formulation of liquid detergent compositions containing greater concentrations of low 2-phenyl linear alkylbenzene sulfonate surfactants.

Description

SOLUBILIZATION OF LOW ALKYLBENZENE SULPHONATES IN 2-PHENYL BACKGROUND OF THE INVENTION 1. Field of the invention The present invention relates generally to liquid cleaning compositions and, more particularly, to improving the solubility of alkylbenzene sulfonate, such as low alkylbenzene sulfonates in 2-phenyl, in aqueous cleaning formulations, by the addition of oxide block copolymers. ethylene / propylene oxide to the formulation.

Description of the related art Linear alkylbenzene sulphonates ("LAS") are widely used surfactants in commercial cleaning products due to their effectiveness as detergents, ease of biodegradation and relatively low cost. Typically, the linear alkylbenzene sulfonates are produced via linear alkylbenzene intermediation suifonation. Linear alkylbenzenes are typically manufactured on an industrial scale using one of two commercial processes which differ from each other primarily by virtue of the catalyst system used. In this regard, one process uses an aluminum trichloride catalyst, while the other process uses a hydrogen fluoride catalyst. The two processes result in linear alkylbenzene products with different phenyl isomer distributions. For example, a typical phenylene isomer distribution for products of the aluminum trichloride process is about 30 ° of 2-phenyl isomer and about 22% of the 3-phenyl isomer. In contrast, a typical phenyl isomer distribution for products of the hydrogen fluoride process is about 20o of 2-phenyl isomer and about 20o of 3-phenyl isomer, although the reported values may differ. The process product of aluminum trichioride, which is relatively high in 2-phenyl isomer content, is often referred to as "high 2-phenyl" linear alkylbenzene, while the product of the hydrogen fluoride process, the which is relatively low in the 2-phenyl isomer content, is often referred to as a linear "low 2-phenyl alkylbenzene." Linear alkylbenzene sulphonates are known to exhibit different physical properties depending on the position of the aromatic group in the alkyl chain Therefore, linear 2-phenyl high alkylbenzene sulphonates have physical properties that differ from linear low alkylbenzene sulphonates in 2-phenyl For example, linear alkylbenzene sulfonates high in 2-phenyl typically have a higher solubility in an aqueous medium compared to the linear low alkylbenzene sulphonates in 2-phenyl In addition, an aqueous solution comprising a linear alkylbenzene sulfonate high in 2-phenyl may show a higher viscosity than an aqueous solution comprising a linear alkylbenzene sulphonate low in 2-phenyl. In cases where the maximum solubility of the linear alkyl benzene sulfonate in an aqueous detergent formulation is a matter of concern, a product containing a relatively high percentage of compounds in which the aromatic substituent is in the 2 or 3 position and the correspondingly smaller percentage of isomers in which the aromatic substituent is centrally placed with respect to the alkyl chain may be advantageous. In the past, a poor aqueous solubility typically impeded the use of linear low alkylbenzene sulphonate at 2-phenyl in detersive applications requiring a liquid formulation. For example, heavy-duty liquid laundry detergents and liquid dishwashing detergent products have typically been used to use high linear 2-phenyl alkylbenzene sulfonates soluble as anionic surfactants. However, the relatively high cost of surfactants high in 2-phenyl frequently presents a disadvantage for formulators and sellers of cost-conscious detergents. The higher cost of linear alkylbenzene sulfonates high in 2-phenyl than in the case of low 2-phenyl surfactants is based on the higher expense associated with the aluminum trichloride process in relation to the hydrogen fluoride process. Attempts have been made to reduce the cost of liquid detergent formulations using linear alkylbenzene sulphonates. Typically, these have included attempts to facilitate the use of relatively less expensive linear low alkylbenzene sulphonates in 2-phenyl. For example, a method typically used to improve the solubility of linear low alkylbenzene sulphonates in 2-phenyl-in liquid detergent formulations has involved the addition of hydrotropes, such as sodium xylene sulfonate. As used herein, the term "hydrotropes" is defined as a compound that has the property of increasing the aqueous solubility of several slightly soluble organic chemicals. However, the cost advantage of the low 2-phenyl formulations can be partially or completely deviated by the cost of the relatively large amount of hydrotropes that are typically needed to carry out an improvement in the solubility of the low surfactant in 2-phenyl without any improvement attached to the detergency characteristics of the formulation. In addition, the addition of large quantities of hydrotropes to a detergent formulation can have the undesirable effect of decreasing the viscosity of the detergent.

BRIEF DESCRIPTION OF THE INVENTION The method and compositions described relate to increased or improved solubilization of low alkyl 2-phenylbenzene sulphonates in aqueous detergent formulations. Among other things, liquid surfactant compositions are provided which include linear 2-phenyl low alkylbenzene sulfonate surfactants In the practice of the method and the compositions described, the addition of the ethylene oxide / oxide block copolymers of propylene to surfactant compositions that include linear alkylbenzene sulfonate surfactants low in 2-pheny or surprisingly increases Aa solubility of low linear alkylbenzene sulfonates in 2-phenyl in aqueous solutions, resulting in turbidity and transparency points minor, and allows the formulation of liquid detergent compositions containing higher concentrations of the relatively less expensive low linear alkylbenzene sulfonates in 2-phenyl Advantageously, in the practice of the described method, the ethylene oxide block copolymers propylene oxide can be added to an aqueous surfactant composition that which contains a linear alkylbenzene sulfonate low in 2-phenyl to improve the solubility of the linear alkylbenzene sulphonate low in 2-phenyl. Improvements in solubility typically result in a decrease in turbidity and transparency points. For example, the cloud point of a surfactant composition comprising water, sodium hydroxide and a linear low alkyl 2-phenylbenzene sulfonate compound can typically be lowered below the freezing point of water (0 ° C) or less, depending on the concentration of the linear low alkylbenzene sulfonate present in 2-phenyl and depending on the amount of the solubility improver of ethylene oxide / propylene oxide block copolymers that is added. In the practice of the method described, the addition of the ethylene oxide / propylene oxide block copolymer compounds to an aqueous surfactant composition that lowers the cloud point of the composition, typically low as about 15 ° C to about - 8 ° C, more typically as low as about 10 ° C to about -6 ° C, and more typically as low as about 3 ° C to about -5 ° C. Such a surfactant composition may also include a solvent in addition to water, such as an alcohol containing 1 to about 6 carbon atoms. Such a surfactant composition may also include one or more solvents in addition to (or instead of), such as alcohols, glycols, glycol ethers, mixtures thereof, etc. Suitable alcohols include, but are not limited to, straight chain alkyl alcohols (including those containing from 1 to 6 carbon atoms, for example methanol, ethanol, n-propanol, n-hexanol, etc.), alkyl alcohols branched chain (including those containing from 3 to 6 carbon atoms, eg isopropanol and secondary butanol, etc.), glycols such as propylene glycol, diglycols such as dipropylene glycol and triglycols such as triethylene glycol and glycol ethers such as butylene glycol diethyl ether and dipropylene glycol methyl ether. Such solvents (when added in addition to water) are typically added in an amount of between about 1% and about 20%, alternatively between about 5% and about 15%, alternatively between about 10% and about 15% of the total weight of the composition, although greater or lesser amounts of such solvents can be suitably used. In one aspect, then, this invention is a surfactant composition that includes at least one alkylbenzene sulfonate; and at least one solubility improver of ethylene oxide / propylene oxide block copolymer; wherein the ethylene oxide / propylene oxide block copolymer has an ethylene oxide content greater than 15% by weight of the molecule. The ethylene oxide / propylene oxide block copolymer can have the formula: CH3 HO [CH2CH20] [CH2CHO] [CHCH20] H In one embodiment, the alkylbenzene sulfonate can be a linear 2-phenyl low alkylbenzene sulfonate. The alkylbenzene sulfonate may be a linear alkylbenzene sulfonate having a 2-phenyl isomer content of less than or equal to 25% by weight. Alternatively, the alkylbenzene sulfonate can be a linear alkylbenzene sulfonate having a 2-phenyl isomer content of up to about 20% by weight. The surfactant composition may further include a solvent. The solvent may include at least one of water, alcohol, glycol, glycol ether or a mixture thereof. The solvent may include at least one of water, alcohol having 1 to about 6 carbon atoms, or a mixture thereof. An alkyl alkyl linear alkyl benzene chain may have from about 8 to about 16 carbon atoms. A cation of the alkylbenzene sulfonate may include, for example, at least one ammonium, substituted ammonium, an alkali metal, an alkaline earth metal or a mixture thereof. Typically, the alkali metal includes sodium.

The alkylbenzene sulfonate may be present in an amount of about 5% to about 30% by total weight of the composition, and the ethylene oxide / propylene oxide solubility improver may be present in an amount of about 0.5% to about 10% by total weight of the composition. The alkylbezene sulfonate may be present in an amount of about 15% to about 30% by total weight of the composition, and the ethylene oxide / propylene oxide solubility improver may be present in an amount of about 0.8% to about 8% by total weight of the composition. The ethylene oxide / propylene oxide block copolymer may be present in a molar ratio of about 46: 1 to about 4: 1 relative to the low 2-phenyl alkylbenzene sulfonate. In one embodiment, the cloud point of the surfactant composition may be about 17 ° C or less, or alternatively from about 17 ° C to about -10 ° C. In another embodiment, the point of transparency of a surfactant composition may be about 23 ° C or less, or alternatively from about 23 ° C to about -5 ° C, or alternatively from about 23 ° C to about -2 C. In a further embodiment, a sodium LAS surfactant composition can have a reduction in the cloud point of between about 10 ° C and about 38 ° C when compared to a similar sodium LAS surfactant composition lacking the enhancer of the described solubility of the ethylene oxide / propylene oxide block copolymer. In yet another embodiment, a sodium LAS surfactant composition can have a reduction in point of transparency of between about 5 ° C and about 35 ° C when compared to a similar sodium LAS surfactant composition lacking the enhancer. Described solubility of ethylene oxide / propylene oxide block copolymer. In another aspect, this invention is a surfactant composition that includes a solvent and a linear alkylbenzene sulfonate, the linear alkylbenzene sulfonate has a 2-phenyl isomer content of about 14% to 25% by weight; and wherein the alkylbenzene sulfonate is present in an amount of about 2% to about 40% by total weight of the composition; wherein the ethylene oxide / propylene oxide solubility improver is present in an amount from about 0.2% to about 10% by total weight of the composition; wherein the ethylene oxide / propylene oxide block copolymer has an ethylene oxide content greater than about 15% to about 80% by weight of the copolymer molecule; and wherein the ethylene oxide / propylene oxide block copolymer has the formula: The ethylene oxide / propylene oxide block copolymer can have an ethylene oxide content of 20% to about 70% by weight of the molecule. The solvent may include at least one of water, alcohol, glycol ether or a mixture thereof. The solvent may include at least one of water, alcohol having from 1 to about 6 carbon atoms, or a mixture thereof. The alkyl chain of the alkylbenzene sulfonate surfactant may contain from about 8 to about 16 carbon atoms. A cation of the alkylbenzene sulfonate surfactant may include at least one of ammonium, substituted ammonium, an alkali metal, an alkaline earth metal or a mixture thereof. Typically, the alkali metal includes sodium. The cloud point of the surfactant composition may be about 17 ° C or less, or alternatively about 17 ° C to about -10 ° C. The point of transparency of the surfactant solution may be about 23 ° C or less, or alternatively from about 23 ° C to about -5 ° C, or alternatively from about 23 ° C to about -2 ° C. .

In yet another embodiment, a sodium LAS surfactant composition can have a reduction in the cloud point of between about 10 ° C and about 38 ° C when compared to a similar sodium LAS surfactant composition lacking the enhancer of the described solubility of the ethylene oxide / propylene oxide block copolymers. In a further embodiment, the sodium LAS surfactant composition can have a reduction in the transparency point of between about 5 ° C and about 35 ° C when compared to a similar composition of sodium LAS surfactant lacking the enhancer of the described solubility of the ethylene oxide / propylene oxide block copolymers. In still another aspect, this invention is a surfactant composition that includes from about 2% to about 40% linear low alkylbenzene sulfonate in 2-phenyl per total weight of the composition; from about 0.2% to about 8% ethylene oxide / propylene oxide block copolymer by total weight of the composition; and from about 97.8% to about 52% solvent by total weight-of the composition; wherein the solvent includes at least one of water, alcohol containing from 1 to about 6 carbon atoms or a mixture thereof; wherein the alkyl chain of the linear 2-phenyl lower alkylbenzene sulfonate surfactant contains from about 8 to about 16 carbon atoms; wherein the ethylene oxide / propylene oxide block copolymer can have an ethylene oxide content of from about 20% to about 80% by weight of the copolymer molecule, and an ethylene oxide content of about 20% by weight of the copolymer molecule. less than about 80% by weight of the copolymer molecule, and wherein the block copolymer of ethylene oxide / propylene oxide can be represented by the formula: CH3 HO [CH2CH20] [CH2CHO] [CH2CH20] H The solvent may include water. In one embodiment the cloud point of a surfactant composition, typically having a sodium cation, may be about 17 ° C or less, or alternatively from about 17 ° C to about -10 ° C; or the point of transparency of the surfactant composition may be about 23 ° C or less, or alternatively from about 23 ° C to about -5 ° C, or alternatively from about 23 ° C to about - 2 C. In another embodiment, the surfactant composition described may be sodium LAS and have a reduction in the cloud point of between about 10 ° C and about 38 ° C; or it may have a reduction in the cloud point of between about 5 ° C and about 35 ° C when compared to conventional serum LAS without the improvement in solubility described in the ethylene oxide / propylene oxide block copolymers. A cation of the linear 2-phenyl lower alkylbenzene sulfonate surfactant may include sodium. In another additional aspect, this invention is a method for improving the solubility of alkylbenzene sulfonate in a surfactant composition including alkylbenzene solvent and sulfonate, the method includes the steps of: adding an ethylene oxide / oxide block copolymer solubility improver. propylene to the surfactant composition; wherein the ethylene oxide / propylene oxide block copolymer can have an ethylene oxide content greater than 15% by weight of the molecule. In one embodiment, the ethylene oxide / propylene oxide block copolymer can have the formula: CH3 HO [CH2CH20] [CH2CHO] [CH2CH20] H The alkylbenzene sulfonate can be a low 2-phenyl alkylbenzene sulfonate. The alkylbenzene sulfonate may have a 2-phenyl isomer content of less than or equal to 25% by weight. The alkylbenzene sulfonate may have a 2-phenyl isomer content of up to about 20% by weight. The solvent may include at least one of water, alcohol having from 1 to about 6 carbon atoms, glycols, glycol ethers or a mixture thereof. In one embodiment, the solvent includes water. In one embodiment, the alkyl chain of the alkylbenzene sulfonate may have from about 8 to about 16 carbon atoms. The alkali metal may include sodium. In one embodiment, the ethylene oxide / propylene oxide block copolymer can have an ethylene oxide content of greater than about 15% to about 80% by weight of the copolymer molecule. In another embodiment, the ethylene oxide / propylene oxide block copolymer can have an ethylene oxide content of from about 20% to about 30% by weight of the copolymer molecule. In another embodiment, the ethylene oxide / propylene oxide block copolymer can have an ethylene oxide content of from about 20% to about 70% by weight of the copolymer molecule. In one embodiment, the step of adding the ethylene oxide / propylene oxide block copolymer to the surfactant composition includes the step of adding a sufficient amount of ethylene oxide / propylene oxide block copolymer to the surfactant composition. so as to result in a surfactant composition which includes from about 2% to about 40% low alkylbenzene sulfonate in 2-phenyl per total weight of the composition; and from about 0.2% to about A_ of ethylene oxide / propylene oxide block copolymer by total weight of the composition. In another embodiment, the step of adding includes: adding an ethylene oxide / propylene oxide to the surfactant composition, typically a surfactant composition containing sodium LAS; and decreasing the cloud point of the surfactant composition to about 17 ° C or less, or alternatively from about 17 ° C to about -10 ° C; or decrease the point of transparency of the surfactant composition to about 23 ° C or less, or alternatively from about 23 ° C to about -5 ° C, or alternatively from about 23 ° C to about -2 ° C . In another embodiment, the step of adding includes: adding an ethylene oxide / propylene oxide to the surfactant composition, typically a surfactant composition containing sodium LAS; and decreasing the cloud point of the surfactant composition between about 10 ° C and about -7 ° C; or reducing the point of transparency of the surfactant composition between about 10 ° C and about -1 ° C.

DETAILED DESCRIPTION OF THE ILLUSTRATIVE MODALITIES The method described and the compositions relate to an improved or increased solubilization of low alkylbenzene sulfonates in 2-phenyl in aqueous detergent formulations. Among other things, liquid surfactant compositions comprising linear alkylbenzene sulphonate surfactants low in 2-phenyl are provided. In the practice of the described method and the compositions, the addition of ethylene oxide / propylene oxide block copolymers surfactant compositions including linear alkylbenzene sulfonates low in 2-phenyl surprisingly increase the solubility of alkylbenzene sulphonates linear low 2-phenyl in an aqueous solution. Advantageously, an increase in the solubility of the linear alkylbenzene sulphonate low in 2-phenyl results in a lower solution with a turbidity point and lower transparency points, and allows a formulation of liquid detergent compositions containing higher concentrations of linear lower alkylbenzene sulphonate surfactants in relatively less expensive 2-phenyl. As used herein, the term "cloud point" is defined as the temperature at which a substantially transparent solution becomes cloudy or cloudy. As used herein, the term "transparency point" is defined as the temperature at which an opaque or cloudy solution becomes substantially transparent. In any case, a substantially transparent solution is an isotropic-looking solution, in which the insoluble material is not visually discernible in the solution. In this regard, the cloud point or the transparency point, or both, can be used as an indicator of the mutual solubility of the components in an aqueous solution. In the case of many detergent formulations incorporating LAS, this indicates the solubility / insolubility of the LAS component. In this regard, the cloud point or the transparency point, or both, can be used as an indicator of the solubility of anionic surfactants in aqueous solution. All other parameters remain the same, the lower turbidity point or a point of transparency, or both, is indicative of a greater solute solubility. As illustrated in the examples included herein, the determinations of the turbidity and transparency points show that the addition of ethylene oxide / propylene oxide block copolymers with relatively low molecular weight surprisingly increases the solubility of sulfonates linear alkylbenzene 2-phenyl benzenes in aqueous solutions, such as liquid laundry detergent formulations for heavy duty laundry. Advantageously, the ethylene oxide / propylene oxide block copolymer solubility improvers of the method described in the compositions are capable of lowering the turbidity and transparency points of the linear low alkylbenzene sulphonate surfactants in 2-phenyl at temperatures lower than the turbidity point temperatures that are typically obtained by hydrotropes. Advantageously, the solubility improving effect of the surfactant compositions described is typically obtained g lower ethylene oxide / propylene oxide block copolymer concentrations at the concentrations required for hydrotropes. The method and compositions described are useful with all types of liquid surfactant compositions in which linear alkylbenzene sulfonates are present as a surfactant component. Examples of such liquid compositions include, but are not limited to, heavy duty laundry detergents, herbicide emulsifiers, hard surface cleaners, bath cleaners, general purpose cleaners, vehicle washing detergents and cleaners for jars as well as detergents. light work liquids. Surprisingly, according to the present disclosure, ethylene oxide / propylene oxide block copolymer materials can be used to improve the solubility of low linear 2-phenyl alkylbenzene sulphonates. Significantly, it has been shown that ethylene oxide / propylene oxide block copolymer materials offer superior solubility improvement qualities over conventional solubility improvers such as amines and hydrotope materials. The addition of copolymers and ethylene oxide / propylene oxide block, more typically, ethylene oxide / propylene oxide block copolymers of relatively lower molecular weight, acts to reduce the turbidity and transparency points of the materials of linear alkylbenzene sulfonate low in 2-phenyl at lower temperatures. Therefore, block copolymers of ethylene oxide / propylene oxide improves the solubility and applicability of linear low alkylbenzene sulphonate materials in 2-phenyl in detergent formulations. The unexpected advantages of this method are the permitted use of low linear alkylbenzene sulphonate products in 2-phenyl or the use of considerably higher concentrations of these products in liquid detergent formulations and at the same time retaining the stability and desired aesthetic properties in these formulations. In the practice of the method and the compositions that are described, any of the low 2-phenyl alkylbenzene sulfonate compounds or mixture thereof suitable for use in liquid detergent formulations is one that can be used. Low 2-phenyl alkylbenzene sulfonate compounds include but are not limited to those prepared by alkylation of benzene with straight-chain monoolefins in the presence of hydrogen fluoride as a catalyst, followed by suifonation with any suitable sulfonating agent. For example, the preparation of suitable 2-phenyl low alkylbenzene sulfonate compounds can include the dehydrogenation of straight chain paraffins on a suitable catalyst, to provide a mixture containing the desired straight chain monoolefins as well as straight chain paraffins which has not reacted The mixture can be passed to an alkylation unit where the straight chain monoolefins can be used to alkylate benzene to form the desired straight chain alkylbenzene compounds, as well as unreacted linear chain paraffins which are they can be easily separated from them by processes such as distillation. The straight chain alkyl benzene compounds prepared therefrom with any suitable sulfonating agent, such as sulfur trioxide, mixtures of sulfur dioxide and sulfur trioxide, chlorosulfonic acid or the like, by conventional methods. The resulting sulphonic acid can be neutralized with an alkali metal hydroxide or carbonate, such as potassium hydroxide or sodium carbonate, or by the use of any other suitable base conventionally used in the preparation of ammonium or alkali metal salts of acids Arylsulphonic It will be understood that the benefit of the method described and the compositions can be carried out in solutions including any alkylbenzene sulfonate compound, including those having varying molecular weights, alkyl chain length and combination of phenyl position in the alkyl chain. Examples of such compounds are described in U.S. Patent No. 3,776,962; U.S. Patent No. 5,152,933; U.S. Patent No. 5,167,872; Drazd, Joseph C. and ilma Gorman, "Formulating Characteristics of High and Low 2-Phenyl Linear Alkylbenzene Sulfonates in Liquid Detergents", JAOCS, 65 (3): 398-404, March 1988; Sweeney,. A. and A. C. Olson, "Performance of Straight-Chain Alkylbenzene Sulfonates (LAS) in Heavy-Duty Detergents", JAOCS, 41: 815-822, December 1964; Drazd, Joseph C, "An Introduction to Light Duty (Dishwashing) Liquids Part I. Raw Materials", Chemical Times & Trends, 29-58, January 1985; Cohen, L. et al., "Influence of 2-Fhenyl Alkane and Tetralin Content on Solubility and Viscosity of Linear Alkylbenzene Sulfonate", JAOCS, 72 (1): 115-122, 1995; Smith, Dewey L., "Impact of Composition on the Performance of Linear Sodium Alkylbenzenesulfonate (NaLAS)", JAOCS, 74 (7).-837-845, 1997; van Os, N.M. et al. , "Alkylarenesulphonates: The Effect of Chemical Structure on Phisico-chemical Properties", Tenside Surf. Det. , 29 (3): 175-189, 1992; Moreno, A. et al. , "Influence of Structure and Counterions on Physicochemical Properties of Linear Alkylbenzene Sulfonates", JAOCS, 67 (8): 547-552, August 1990; Matheson, K. Lee and Ted P.

Matson, "Effect of Carbon Chain and Phenyl Isomer Distribution on Use Properties of Linear Alkylbenzene Sulfonate: A Comparison of 'High' and 'Low' 2-Phenyl LAS Homologs", JAOCS, 60 (9): 1693-1698, September 1983; Cox, Michael F. and Dewey L. Smith, "Effect of LAB composition on LAS Performance", 1NFORM, 8 (1): 19-24, January 1997; and patent application Serial No. 08 / 598,692 filed February 8, 1996); all of the above references are incorporated herein by reference in their entirety. In one embodiment, the alkylbenzene sulfonate compounds used according to the described compositions and methods and having the characteristics described herein include those having a linear alkyl group. Typical linear alkyl chain lengths are between about 8 and about 16 carbon atoms, although longer and shorter lengths are possible. Typically, low alkylbenzene sulfonates in 2-phenyl are used. In this regard, the low 2-phenyl alkylbenzene sulfonate compositions may include mixtures of species having varying molecular weights. Typically, one or more low 2-phenyl alkylbenzene sulfonate compounds such as their sodium salts, having an average molecular weight in the range of about 292 to about 404, and an average alkyl carbon number of about 8 to about 16 are the ones that are used. Alternatively, one or more low alkyl 2-phenylbenzene sulfonate compounds, such as their sodium salts, having an average molecular weight of about 320 to about 376 and an average alkyl carbon number of about 10 to about 14 are used. Alternatively, one or more low 2-phenyl alkylbenzene sulfonate compounds are used as their sodium salts having an average molecular weight from about 334 to about 362, and an average alkyl carbon number from about 11 to about 13. In other embodiments (such as those that utilize cations in addition to sodium), it may also include mixtures of species having varying molecular weights. Typically, one or more low 2-phenyl alkylbenzene sulfonate compounds based on 2-phenyl low alkylbenzene sulfonate compounds having an average molecular weight in the range of about 190 to about 302, and a carbon number are used. alkyl average from about 8 to about 16. Alternatively, one or more such compounds based on 2-phenyl low alkylbenzene compounds having an average molecular weight of about 218 to about 274 and an average alkyl carbon number of about 10 to approximately 14 are those that are used. Alternatively, one or more such compounds based on 2-phenyl low alkylbenzene compounds having an average molecular weight of about 232 to about 260 are used., and an average alkyl carbon number of from about 11 to about 13. Table 24 illustrates additional possible embodiments, which include molecular weight information for various 2-phenyl low alkylbenzene compounds having alkyl carbon chain lengths variable. Information is also provided for the acid / sulfate and sodium / sulfate derivatives of these low alkyl 2-phenylbenzene compounds which are useful alone and in various combinations in the practice of the described compounds and of the method. The alkylbenzene sulfonates suitable for use in the method described in the compositions include any alkylbenzene sulfonate known in the art to be effective or suitable for detergent formulations and including, but not limited to those alkylbenzene sulphonates having a content of 2-phenyl minor isomer of about 30% by weight of the molecule, alternatively less than about 29% by weight of the molecule, alternatively less than about 28% by weight of the molecule, alternatively less than about 27% by weight of the molecule, alternatively less than about 26% by weight of the molecule, alternatively less than about 25% by weight of the molecule, alternatively less than about 24% by weight of the molecule, so alternative less than about 23% by weight of the molecule, alternatively less than about 22% by weight of the molecule ula, alternatively less than about 21% by weight of the molecule, alternatively less than about 20% by weight of the molecule and alternatively less than about 19% by weight of the molecule. However, with the benefit of this description it will be understood that alkylbenzene sulfonates having a 2-phenyl isomer content of 30% by weight of the molecule or greater, can also be used. Alkylbenzene sulfonates having a 2-phenyl isomer content from about 10% to less than about 25% by weight of the molecule, alternatively from about 10% to about 24% by weight of the molecule, are also suitable. alternatively from about 10% to about 23% by weight of the molecule, alternatively from about 10% to about 22% by weight of the molecule, alternatively from about 10% to about 21% by weight of the molecule, alternatively from about 10% to about 20% by weight of the molecule, and alternatively from about 10% to about 19% by weight of the molecule. Alkylbenzene sulfonates having a 2-phenyl isomer content of about 12% - less than about 25% by weight of the molecule, alternatively from about 12% to about 24% by weight of the molecule, are also suitable. alternatively from about 12% to about 23% by weight of the molecule, alternatively from about 12% to about 22% by weight of the molecule, alternatively from about 12% to about 21% by weight of the molecule, alternatively from about 12% to about 20% by weight of the molecule, and alternatively from about 12% to about 19% by weight of the molecule. Alkylbenzene sulfonates having a 2-phenyl isomer content of about 14% to less than about 25% by weight of the molecule, alternatively from about 14% to about 24% by weight of the molecule, are also suitable. alternatively from about 14% to about 23% by weight of the molecule, alternatively from about 14% to about 22% by weight of the molecule, alternatively from about 14% to about 21% by weight of the molecule, and alternatively from about 14% to about 20% by weight of the molecule, and alternatively from about 14% to about 19% by weight of the molecule. Alkylbenzene sulfonates having a 2-phenyl isomer content of about 15% to less than about 25% by weight of the molecule, alternatively from about 15% to about 24% by weight of the molecule, are also suitable. alternatively from about 15% to about 23% by weight of the molecule, alternatively from about 15% to about 22% by weight of the molecule, alternatively from about 15% to about 21% by weight of the molecule, and alternatively from about 15% to about 20% by weight of the molecule, and alternatively from about 15% to about 19% by weight of the molecule. As used herein, the term "2-phenyl low alkylbenzene sulfonate" includes those alkylbenzene sulfonates having a 2-phenyl isomer content of about 14% to about 20% by weight. Typically, the phenyl isomer distribution is substantially uniform through the alkane. As used herein "high 2-phenyl alkylbenzene sulfonate" characterizes alkylbenzene sulfonates having a phenyl isomer content greater than 25% to about 30% 2-phenyl isomer by weight. Typically the phenyl isomer distribution is predominantly at the 2 and 3 position of the alkane. It will be understood by those skilled in the art with benefit of this disclosure that low 2-phenyl and high 2-phenyl alkyl benzene sulfonates mixtures are also possible, whereby values of 2-phenyl isomer content are provided between the defined above for the alkylbenzene sulphonates which are low in 2-phenyl and high in 2-phenyl.

A specific 2-phenyl low alkylbenzene sulfonate composition is a sulfonate that is prepared from a linear alkylbenzene known as ALKYLATE 225MR (commercially available from Huntsman Specialty Chemicals Corporation). Other examples of linear alkylbenzenes suitable for preparing linear alkylbenzene sulphonates include, but are not limited to ALKYLATE 215MR, ALKYLATE 229MF, ALKYLATE H230LMR, and ALKYLATE H230HMR (also available from Huntsman Specialty Chemicals Corporation). Suitable processes for sulfonating such linear alkylbenzene include, but are not limited to, using an air sulfonator / S03 or chlorosulfonic acid. In practicing the method and compositions described, a linear 2-phenyl low alkylbenzene sulfonate may include a counter ion or cation suitable for neutralization. In one embodiment, a counterion or cation is typically ammonium or substituted ammonium. In this regard, the substituted ammonium may include, but is not limited to monoethanol ammonium, diethanol ammonium, triethanolammonium or a mixture thereof. In another embodiment, such a counterion or cation may be an alkali metal or alkaline earth metal, or a mixture thereof. Typical alkali metals include, but are not limited to lithium, sodium, potassium, cesium or a mixture thereof. Typical alkaline earth metals include, but are not limited to magnesium, calcium, strontium, barium or a mixture thereof.

The surfactant compositions described can be provided in solid form without a solvent, or in liquid form with a solvent. In those embodiments that use solvents, any solvent suitable for use in the formulation of a liquid detergent formulation can be used. Suitable solvents include, for example, those solvents capable of dissolving low alkylbenzene sulfonates in 2-phenyl. Examples of suitable solvents include, but are not limited to water, alcohols, glycols and glycol ethers, or mixtures thereof. Specific examples of suitable alcohol solvents include, but are not limited to, alcohols having from about 1 to about 6 carbon atoms. In the practice of the method and compositions to be described, typical specific solvents include water, straight chain alkyl alcohols containing 1 to 6 carbon atoms (example: methanol, ethanol, n-propanol, n-hexanol, etc.), branched chain alkyl alcohols containing from 3 to 6 carbon atoms (example: isopropanol and secondary butanol), glycols such as propylene glycol, diglycols such as propylene glycol and triglycols such as triethylene glycol and glycol ethers such as butylene glycol diethyl ether and dipropylene glycol methyl ether. Surprisingly it has been found that ethylene oxide / propylene oxide block copolymers having an ethylene oxide content of greater than 15% are effective in improving the solubility of low linear alkylbenzene sulphonate surfactants in 2-phenyl in solution aqueous, while the ethylene oxide / propylene oxide block copolymers having an ethylene oxide content of less than or equal to 15% by weight of the polymer molecule do not act to improve the solubility of the alkylbenzene sulfonate surfactants linear low 2-phenyl in aqueous solution. Evidence of this surprising and unexpected behavior can be found demonstrated by the results provided in the examples, particularly the results of Example 2 and Comparative Example B. With the benefit of this disclosure, those skilled in the art will understand that the procedures of the Examples provide a way of measuring the effectiveness of the particular ethylene oxide / propylene oxide block copolymers (eg, those having a variable content of ethylene oxide) in determining the solubility improvement of the Low linear alkylbenzene sulphonates in 2-phenyl in aqueous solutions and in detergent formulations. Table 23 provides Examples of particular ethylene oxide / propylene oxide copolymers which are suitable and not suitable for improving the solubility of linear low alkylbenzene sulphonate surfactants in 2-phenyl. .In consecuense, the formulation and the practice of the compositions and methods described, the typical examples of ethylene oxide / propylene oxide block copolymer compounds effective to improve the solubility of linear low alkylbenzene sulphonate surfactants in 2-phenyl in aqueous solution include, but are not limited to block copolymers of ethylene oxide / propylene oxide having an oxide content of. ethylene greater than 15% by weight of the molecule, alternatively equal to or greater than about 16% by weight of the molecule, alternatively equal to or greater than about 17% by weight of the molecule, alternatively equal to or greater about 18% by weight of the molecule, alternatively equal to or greater than about 19% by weight of the molecule and alternatively equal to or greater than about 20% by weight of the molecule. These copolymers typically have respective contents of propylene oxide less than 85% by weight of the molecule, alternatively less than or equal to about 84% by weight of the molecule, alternatively less than or equal to about 83% by weight of the molecule, alternatively less than or equal to about 82 wt% of the molecule, alternatively less than or equal to about 81 wt% of the molecule, and alternatively less than or equal to about 80% by weight of the molecule. More typically, examples of ethylene oxide / propylene oxide block copolymer compounds effective to improve the solubility of low alkylbenzene 2-phenyl surfactants in solution include ethylene oxide / propylene oxide block copolymers which have an ethylene oxide content greater than 15% to about 80% by weight of the molecule, alternatively from about 16% to about 80% by weight of the molecule, alternatively from about 17% to about 80% by weight weight of the molecule, alternatively from about 18% to about 80% by weight of the molecule, alternatively from about 19% to about 80% by weight of the molecule, and alternatively from about 20% to about 80 % by weight of the molecule. In each case, the remainder of the weight of the molecule typically comprises content of propylene oxide isomer. Alternatively, examples of ethylene oxide / propylene oxide block copolymer compounds effective to improve the solubility of low alkylbenzene 2-phenyl surfactants in solution include ethylene oxide / propylene oxide block copolymers having an ethylene oxide content greater than 15% to about 70% by weight of the molecule, alternatively from about 16% to about 70% by weight of the molecule, alternatively from about 17% to about 70% by weight of the molecule, alternatively from about 18% to about 70% by weight of the molecule, alternatively from about 19% to about 70% by weight of the molecule and alternatively about 20% to about 70% by weight of the molecule. In each case, the remainder of the weight of the molecule typically comprises a content of propylene isomer. Alternatively, examples of ethylene oxide / propylene oxide copolymer compounds effective to improve the solubility of low alkyl 2-phenylbenzene surfactants in solution include ethylene oxide / propylene oxide block copolymers having a content of ethylene oxide greater than 15% to about 50% by weight of the molecule, alternatively from about 16% to about 50% by weight of the molecule, alternatively from about 17% to about 50% by weight of the molecule, alternatively from about 18% to about 50% by weight of the molecule, alternatively from about 19% to about 50% by weight of the molecule, and alternatively from about 20% to about 50% by weight of the molecule. In each case, the remainder of the weight of the molecule typically comprises an isomer content of propylene oxide. Alternatively, examples of ethylene oxide / propylene oxide block copolymer compounds effective to improve the solubility of low 2-phenyl alkylbenzene surfactants in solution include ethylene oxide / propylene oxide block copolymers which have an ethylene oxide content greater than 15% to less than 30% by weight of the molecule, alternatively from about 16% to less than 30% by weight of the molecule, alternatively from about 17% to less than 30% by weight of the molecule, alternatively from about 18% to less than 30% by weight of the molecule, alternatively from about 19% to less than 30% by weight of the molecule and alternatively about 20% by weight of the molecule. % to less than 30% by weight of the molecule. In each case, the remainder of the weight of the molecule typically comprises an isomer content of propylene oxide. Alternatively, examples of ethylene oxide / propylene oxide block copolymer compounds effective to improve the solubility of low alkylbenzene 2-phenyl surfactants in solution include ethylene oxide / prspylene oxide block copolymers having an ethylene oxide content greater than 50% to about 80% by weight of the molecule, alternatively from more than 50% to about 70% by weight of the molecule, alternatively more than 50% to about 60% by weight weight of the molecule, alternatively from more than 55% to about 80% by weight of the molecule, alternatively from more than 55% to about 70% by weight of the molecule, and alternatively from more than 55% to about 60% by weight of the molecule. In each case, the remainder of the weight of the molecule is typically constituted by the content of propylene oxide isomer. In combination with any of the above mentioned amounts of ethylene oxide, an ethylene oxide / propylene oxide may include a hydrophobe of propylene oxide having any effective molecular weight for solubility improvement according to the methods described herein. Typically, the molecular weight of the hydrophobe of propylene oxide is from about 900 to about 3600, although molecular weights greater than 3600, greater than 4000 and less than 950 or less than 900 are also possible. Accordingly, the enhancers of Suitable ethylene oxide / propylene oxide block copolymer solubility can typically be represented by the formula: [CH2 f? 3 HO [CH2CH20] CHO] [CH2CH20] H or alternatively H3 HO [CH2CH20] x [CH2 fCHO] and [CH2CH20] ZH where; number of ethylene oxide blocks number of ethylene oxide blocks Y number of propylene oxide blocks In one embodiment, for example, for percent weight of ethylene oxide of between about 20% and about 70%, x typically is between about 3.5 and about 150, and typically is between about 21 and about 70, and z is typically between about 3.5 and about 150. Specific examples of suitable ethylene oxide / propylene oxide block copolymer solubility improvers include, but are not limited to, ethylene oxide / propylene oxide block copolymer products sold by Huntsman Chemical Corporation under the trade name SURFONICMR (such as SURFONIC POA L-35MR, SURFONIC POA 1-42MR, SURFONIC POA L-44fIF and SURFONIC POA L-62MR). Table 1 includes the percentage of ethylene oxide and propylene oxide, as well as the values of x, y and z in the formula given above, for these SURFONIC compounds.

Table 1 - Characteristics of the SURFONICMR copolymer from Huntsman Other specific examples of solubility improvers of suitable ethylene oxide / propylene oxide block copolymers include, but are not limited to, ethylene oxide / propylene oxide block copolymer products sold by BASF under the tradename PLURONIC "F (such as, for example, PLURONIC L122HR, PLURONIC L92MR, PLURONIC L72MP, PLURONIC L62MF, PLURONIC L42MR, PLURONIC P123MR, PLURONIC P103MR, PLURONIC L63MR, PLURONIC L43MR, PLURONIC P104MR, PLURONIC P94R, PLURONIC P84KR, PLURONIC L64MR, PLURONIC L44MR, PLURONIC P105MR, PLURONIC P85MF, PLURONIC P75MR, PLURONIC P65MR, PLURONIC L35MR, PLURONIC F127MR, PLURONIC F87HR, PLURONIC F77MR, PLURONIC F108MP, PLURONIC F98"PLURONIC F88f'A PLURONIC F68MR, PLURONIC F38f'A In the case of SURFONICMR copolymer lines , and PLURONICMR, each compound is identified by an alphabetical assignment followed by a numerical designation.The alphabetic designations L, P and F indicate the physical form of The product (liquid, in paste or in flakes). The last integer or the whole number in the fraction digit in the numerical desgination of an individual compound indicates the approximate weight in% of poly (oxyethylene) idrophile in the total molecule multiplied by 0.1. The digit or digits that press the last integer or the whole number in the fractional digit (or the first digits after the alphabetic designation) indicate the approximate molecular weight of the hydrophobic poly (oxypropylene) divided by 300. The surfactant compositions described include a solvent that typically has reduced turbidity and transfer points relative to conventional surfactant / solvent compensations (ie, with similar components, but without the described ethylene oxide / propylene oxide solubility improving materials). With the benefit of this disclosure, it will be understood by those skilled in the art that detergent compositions having any suitable amount of alkylbenzene sulfonate known in the art may benefit from the solubility improvers of ethylene oxide / ethylene oxide copolymer. propylene of the present disclosure and it will be further understood that any amount or mixture of ethylene oxide / propylene oxide copolymers effective to improve the solubility of such alkylbenzene sulfonates in detergent compositions, or effective to decrease the point of turbidity or Transfer of such compositions can be used. Typically, the sodium LAS modalities of the surfactant compositions that are described have reduced haze and transparency spots of from about 15 ° C to about 35 ° C, alternatively, from about 20 ° C to about 30 ° C. to compositions only of similar conventional sodium LAS. In various modalities, surfactant solutions containing sodium LAS described may have cloud points equal to or less than about 25 ° C, about 20 ° C, about 15 ° C, about 10 ° C, about 5 ° C, about 0 ° C and approximately -5 ° C, respectively. In several additional embodiments, the surfactant solutions containing sodium LAS described may have transfer points less than or equal to about 30 ° C, about 25 ° C, about 20 ° C, about 15 ° C, about 10 ° C and approximately 5 ° C, respectively. For example, in the practice of one embodiment of the method and compositions described, a surfactant or detergent composition typically includes between about 2% and about 40% by weight of sulfonate surfactant. linear low alkylbenzene in 2-phenyl sodium, between about 0.2% and about 10% by weight of ethylene oxide / propylene oxide solubility improver between about 97.8% and about 50% by weight of water or alternatively other solvents (such as as alcohol, glycol, glycol ether, etc.). In another embodiment, a surfactant composition can include between about 5% and about 30% by weight of linear low alkylbenzene sulphonate surfactant in 2-phenyl sodium, between about 0.8% and about 7% by weight of solubility enhancer. ethylene oxide / propylene oxide and between about 94.2% and about 63% by weight of water or alternatively other solvents (such as alcohol, glycol, glycol ether, etc.). In a further surfactant composition embodiment, a surfactant composition includes between about 15% and about 30% by weight of linear alkylbenzene sulphonate surfactant low in sodium 2-phenyl, between about 1% and about 5% by weight of ethylene oxide / propylene oxide solubility improver and between about 84% and about 65% by weight of water or alternatively other solvents (such as alcohol, glycol, glycol ether, etc.). With the benefit of this disclosure, it will be understood by those skilled in the art that a surfactant composition may take the form of a liquid or alternatively a paste or solid form, depending on the molecular weight of the LAS and the ethylene oxide copolymer components. / propylene oxide, or if the amount of solvents is greatly reduced or eliminated. In other typical embodiments, a sulfonate surfactant composition based on linear 2-phenyl low alkylbenzene may also contain optional additives including, but not limited to cationic co-surfactant, anionic co-surfactant, non-ionic co-surfactant, builder, enzymes, oxidation enzyme remover, soil suspending agents, soil release polymer, bactericides, coloring agents, foam control agents, corrosion inhibitor, perfume or a mixture thereof. Examples of such suitable additives include, but are not limited to, those additives described in the pending PCT application No.

PCT / US97 / 06473 (International Publication No. WO97 / 39089), which is incorporated herein by reference. The following examples are illustrative and should not be considered as limiting the scope of the invention or the claims thereof.

EXAMPLES Example 1 - Solutions of LAS without salt of added sodium sulfate ("without salt") The following example uses an aqueous solution of 21.4% by weight of sodium LAS. The turbidity point and the transparency points of the sodium LAS solutions are evaluated with the solution of solubilization enhancing materials in increments by weight. In all experiments LAS-acid based on ALKYLATE 225 was used. "This LAS-acid is neutralized with sodium hydroxide, as described in the SLAS preparation section below, up to a pH of = 8. Sodium hydroxide is added to the point at which "salt is removed" from SLAS (the point at which SLAS is separated from the solution as a solid phase).

Preparation of LAS test solution The following examples of test sodium LAS materials are prepared, having the following composition: LAS-acid = 5,000 g (20%) Sodium hydroxide = 0.653 g (2.61%) Water = 19,353 g (77.39%) This composition , when expressed in terms of neutralized LAS materials is as follows: Sodium = 5,324 g (21.4%) Water = 19,665 g (78.6%) The percentage in compositions obtained, as increments of additives that are added, are shown in tables 7-14. They are shown as percent based on LAS-acid.

Procedure for evaluating the turbidity / transparency point For use in experiments with sodium LAS solutions, a special turbidity point / transparency point determination device is manufactured, consisting of a lined cell which contains isopropanol, and isopropanol is also passed from a refrigerant through the outer jacket 'cell. Lower temperatures -20 ° C can be obtained for this circulating isopropanol. Temperatures well below -10 ° C can be obtained for a test sample submerged in the isopropanol contained in the cell. A test tube which contains the sample to be evaluated is immersed and a thermometer is immersed in the isopropanol in the cell and evaluated to determine the development of turbidity under conditions of continuous mixing by means of the thermometer. The temperature at which a resistant turbidity occurs is identified as the cloud point.

The points of transparency are determined by allowing the test sample, in the test tube, to slowly warm up, after complete turbidity, under ambient conditions, until a state of complete isotropic appearance is obtained. The sample, while hot, is agitated intermittently by means of the thermometer that remains in the test tube. The temperature at which the test sample becomes isotropic is recorded as the point of transparency.

Turbidity / transparency point results The value of ([additive] / ([additive] + [SLAS])) x 100 is given in table 11 as a measure of additive efficacy ("EF"). This represents the percentage of total SLAS plus the additive used that is additive. This value, for each additive, to the extent that the turbidity point reaches 0 ° C or less for the first time, can be used as an indicator of additive efficiency. The smaller the number, the more effective the additive is. The above equation is represented in the present by "EF". In this example, the turbidity point / transparency point determinations were performed for a solution containing linear low alkyl 2-phenyl sulfonate surfactant ("LAS") in the presence of varying amounts of the copolymer copolymer solubility improvers. described ethylene oxide / propylene oxide block having ethylene oxide contents greater than about 20% by weight of the molecule. Initially, each solution contains 5.0 g of a linear 2-phenyl low alkylbenzene sulfonate compound ("225A" available from Huntsman Chemical Corporation), 0.653 g of sodium hydroxide and 19,353 g of water. Increasing amounts of the ethylene oxide / propylene oxide block copolymer enhancing agent are added by titration to each solution and then the cloud point and the transparency point are determined. Tables 2-5 contain detailed information regarding the turbidity points and transparency points of the linear 2-phenyl low alkylbenzene sulfonate solutions to which one of the oxide block copolymer solubility improvers has been added. of ethylene / propylene oxide described (SURFONIC POA L-35MR, SURFONIC POA L-42MR, SURFONIC POA L-44MR and SURFONIC POA L-62MP, available from Huntsman Chemical Corporation). As can be seen from the data in Tables 2-5, both at the cloud point and the transparency point substantially decreases by the addition of each of the ethylene oxide / oxide oxide block copolymer solubility improvers. propylene tested. The "SURFONIC POA" materials are ethylene oxide / propylene oxide block copolymers available from Huntsman Corporation. Similar materials are also available from BASF.

Table 2 - Addition of POA L-421" Table 3 - Addition of POA L-62 * Table 4 - Addition of POA L-44 * Table 5 Add POA L-35 * Comparative Example A - Various additives tested with LAS solutions that do not have added sodium sulfate salt ("without salt") In this example, turbidity point / transparency point determinations were made for the same solution containing a linear 2-phenyl low alkylbenzene sulfonate surfactant of Example 1. Increasing amounts of conventional solubility enhancing agents are added by titration to each solution and then determine the turbidity points and the transfer points. Tables 6-10 contain detailed information regarding the transparency points and turbidity points of the linear 2-phenyl low alkylbenzene sulphonate solution to which conventional solubility enhancers have been added ("SXS", "MDEA"). "," DMEA "," DOWFAX 3B2"or" DO FAX HYDRO "). SXS is sodium xylene sulfonate commonly used as a hydrotrope and solubilizing agent. MDEA is methyldiethanolamine and DMEA is dimethylethanolamine. Both amines are used as solubilizing agents for other surfactant systems. SXS, MDEA and DMEA are commercially available from Huntsman Specialty Chemicals Corporation. Dowfax materials are mixtures of sulfonated alkyldiphenylethers commercially available from Dow Chemical Co. These are commonly well known hydrotropes as well as solubilizing agents. It should be noted that by this method, the lowest turbidity points obtained by SXS, DMEA or MDEA are not lower than 0 ° C.

Table 6 - Addition of "SXS II MR Table 7 - Adding "MDEA" Table 8 - Addition of "DMEA" 1 Table 9 - Addition of "DOWFAX 3B2 'Table 10 - Addition of" DOWFAX HYDRO "Table 11 contains a summary of the experimental results of Example 1 (Tables 2-5) and Comparative Example A (Tables 6-10) Table 11 shows the first turbidity point obtained below 0 ° C (if any), the lowest turbidity point obtained and the transparency point corresponding to the concentration of the turbidity point at 0 ° C or, alternatively (in cases where the turbidity point remains above 0 ° C), the lowest transparency point that is obtained for each tested additive. amount of each additive tested as well as a percentage by weight of the complete solution as well as a weight percentage of the amount of alkylbenzene sulfonate low in 2-phenyl plus additive, present in solution As can be seen from these results, three of the four copolymer materials The ethylene oxide / propylene oxide block is able to obtain a lower turbidity point (less than -6 ° C), which is lower than that obtained by any of the conventional additives tested. In addition, a much greater percentage by weight of each of the conventional additives is required to produce a solution with a turbidity point of less than 0 ° C, relative to the ethylene oxide / propylene oxide block copolymer materials. Still with reference to Table 11, the additive% values (expressed as a function of the weight of alkylbenzene additive and sulfonate, and also as a weight function of the total solution) indicate that less than the copolymer additives are required. of ethylene oxide / propylene oxide block described in comparison with the conventional additives tested to make a linear alkylbenzene sulphonate low in 2-phenyl based on ALKYLATE 225MR soluble in an aqueous solution. In this regard, lower turbidity points and transparency points are obtained using smaller amounts of ethylene oxide / propylene oxide block copolymer (SURFONIC POA L-35R, SURFONIC POA L-42MR, SURFONIC POA L-44MR and SURFONIC POA L-62MR than those obtained with the conventional surfactants tested In the aqueous solution, it can be seen that an amount as small as approximately 60% of the amount of SURFONIC POA L-SS ™ 1, SURFONIC POA L-42MR, SURFONIC POA L-44M is necessary to obtain lower turbidity points than those of hydrotropes tested that work best ("DOWFAX 3B2"). The results summarized in Table 11 clearly indicate the superiority of the ethylene oxide / propylene oxide block copolymer materials described to improve the solubility of a linear 2-phenyl lower alkylbenzene sulfonate surfactant in comparison with the operation of several known conventional solubility improving additives.

Table 11 - Summary of the experiments detailed in tables 2-10 EXAMPLE 2 - Solution of sodium LAS using the modified solubility titration method The next two sets of experiments were carried out by a modified solubility titration method. In these experiments, the neutralization of LAS-acid is carried out with sodium hydroxide (final pH 8.5 to 9.5). The sodium LAS is then "salt removed" with a known amount of sodium sulfate before adding the additive.

Preparing SLAS The neutralization of LAS-acid is carried out as above but under controlled conditions. As an example, the following procedure can make a LAS solution of about 20% ALKYLATE 222MR useful for evaluation of the transparency / turbidity points, as follows. A total of 1440 grams of test solution is made, and samples of 25 grams are used for the actual test tests. A final concentration of LAS of sodium in the 25 gram test sample is estimated at approximately 23.7%. The following preparation procedure is used: an amount of 339.2 grams of LAS-ALKYLATE 225MR acid and an appropriate mechanical stirrer are placed in a clean beaker. Then 1100.0 grams of cold deionized water are added, followed by the slow addition of 86.77 grams of a 1: 1 solution of NaOH / deionized water. The resulting mixture is stirred vigorously by the mechanical mixer, cooling with an ice bath as required to maintain a close ambient temperature for 45 to 60 minutes. A pH measurement of the final solution gives a value of 9.0.

Preparation of SLAS test solution "without salt" The test solution is prepared by the following procedures. 1) Place the following materials in the test cell: 12.933 grams of SLAS (23.7% active) 12.57 grams of deionized water 2) The resulting solution is then mixed and stirred until a clear isotropic solution is obtained. 3) Then the following material is added to the solution: 0.565 grams of sodium sulfate 4) The solution is then stirred and mixed until all the sodium sulphate is in solution and the complete solution presents a uniform cloudy appearance ( milky); this solution has a turbidity point of approximately 30 ° C. ) in each case, approximately 0.20 grams of the selected additive is added to this solution and the determinations of the turbidity point and transparency point are made. 6) Then increments of approximately 0.20 grams of the selected additive are added and the cloud point is re-taken after each addition, until a total of approximately 2.6 grams of the selected additive has been added. The results are given in Tables 12-15. It was found that the following copolymers are effective to decrease the turbidity points of the test solution: SURFONIC POA L-62MR, SURFONIC POA L-64MR, SURFONIC POA P-105MR and SURFONIC POA F-127MR. All have a similar efficiency with EF ~ 25 (turbidity points from -l ° C to -5 ° C). The most surprising finding, by far, of the entire test sequence is that SURFONICMR materials with a content of only 10% polyethylene oxide SURFONIC POA L-61MR, SURFONIC POA L-81MR, SURFONIC POA L-101MR) do not decrease the turbidity point of our SLAS test solution. The most surprising thing is the finding that these Copolymer materials increase the cloud point of the test solution. These findings clarify the influence of the polyethylene oxide content versus the polypropylene oxide content of a copolymer additive on the ability of the copolymer to lower the cloud point of the sodium LAS solutions.

Table 12 - Addition of "POA L-62" in or - go »O H O ft.

O you 'O -H O -H to H - - Comparative Example B - Solutions of LAS of sodium ("SLAS") tested with low ethylene oxide polyols (to which the salt of sodium sulphate is added) The following experiments were carried out in a manner similar to that of Example 2. In this example, turbidity point / transparency point determinations were made for a solution containing a linear 2-phenyl lower alkylbenzene sulfonate surfactant, in the presence of varying amounts of ethylene oxide / propylene oxide block copolymer compounds having 15% or less of ethylene oxide by weight of the molecule. Surprisingly, the ethylene oxide / propylene oxide block copolymer compounds tested in this example do not improve the solubility of linear low alkylbenzene sulfonate surfactants in 2-phenyl in aqueous solution. In fact, the ethylene oxide / propylene oxide block copolymer compounds tested in this comparative example decrease the solubility of linear low alkylbenzene sulphonate surfactants in 2-phenyl in aqueous solution, as indicated by the turbidity points and increased transfer points. For these experiments, copolymers with 10% by weight of ethylene oxide and 15% by weight of ethylene oxide are evaluated. Test materials with 15% by weight of ethylene oxide are prepared by combining according to the following ratios. This combination process is used to formulate polyols containing approximately 15% ethylene oxide by weight of the molecule.

L61.5 = 10 grams L62 + 10 grams L61 L-81.5 = 50 grams of L-81 + 10 grams of P-84 (A) L-101.5 = 70 grams L-101 + 10 grams P-105 (A) The results of Comparative Example B are shown in Table 16-22 and summarized with the results of Example 2 in Table 23. These results show that the ethylene oxide / propylene oxide copolymers containing 15% or less of oxide of ethylene do not serve to improve the solubility of linear alkylbenzene sulfonate prepared from ALKYLATE 225MR. They do in fact like block copolymers which contain only approximately 10% ethenoxide / reducing the solubility of linear sodium alkylbenzene sulphonate. For example, the lowest turbidity point and the transfer point for SURFONIC POA L-81.5MR and for SURFONIC POA L-101.5M is produced without copolymer additive. For SURFONIC POA L-61.5MR, the lowest turbidity point occurs in the first increment of additive and then increases with each subsequent increase, while the lowest transfer point without copolymer additive. Significantly, in any case, a turbidity point below 0 ° C is not obtained. This serves to demonstrate the surprising and unexpected nature of the solubility improvers described and the solubilization method, in which the ethylene oxide / propylene oxide block copolymers having an ethylene oxide content greater than 15% by weight and a propylene oxide content of less than 85% by weight have a solubility-improving effect in aqueous solutions with linear alkylbenzene sulphonate surfactants low in 2-phenyl while those having an ethylene oxide content equal to or less than 15%. % by weight of the molecule no.

Table 16 - Addition of "POA L-61" sv.

- ID • O i s ^ or -H? -rl O H Table 18 - Addition of 'POA H01' or Table 20 - Addition of * POA 1 ^ 81" I - - Table 22 - LAS solutions with sodium sulphate salt and low ethylene oxide additives * This turbidity point is the first turbidity point closest to 0 ° C and this turbidity point is one that corresponds to the established turbidity point.

Table 23 - Summary of solubility improvement by ethylene oxide content Table 24 - Molecular weights of linear alkylbenzenes Although the invention can be adapted to various modifications and alternative forms, the specific embodiments have been shown by way of example and have been described herein. However, it should be understood that the invention is not intended to be limited by the particular forms described. Instead, the invention should cover all modifications, equivalents and alternatives that are within the spirit and scope of the invention as defined by the appended claims. In addition, the different aspects of the compositions described and the methods can be used in various combinations or independently. Thus, the invention is not limited only to those combinations shown here, but may also include other combinations.

Claims (39)

1. A surfactant composition comprising: at least one alkylbenzene sulfonate; and at least one solubility improver of ethylene oxide / propylene oxide block copolymer; wherein the ethylene oxide / propylene oxide block copolymer has an ethylene oxide content greater than 15% by weight of the molecule; that the alkylbenzene sulfonate has a 2-phenyl isomer content of less than or equal to 25% by weight, and wherein the surfactant composition is an aqueous solution.

2. The surfactant composition as described in claim 1, wherein the ethylene oxide / propylene oxide block copolymer has the formula: CH3 and HO [CH2CH20] x [CH2CHO] and [CH2CH20] ZH where x is between 3.5 and 150, and is between 16 and 70, and z is between 3.5 and 150.

3. The surfactant composition as described in claim 2, wherein the alkylbenzene sulfonate includes alkylbenzene sulfonates having a 2-phenyl isomer content of 14% to 25% by weight.

4. The surfactant composition as described in claim 2, wherein the alkylbenzene sulfonate is a linear alkylbenzene sulfonate having a 2-phenyl isomer content of 14% to 25% by weight.

5. The surfactant composition as described in claim 2, wherein the alkylbenzene sulfonate is a linear alkylbenzene sulfonate having a 2-phenyl isomer content of up to about 20% by weight.

6. The surfactant composition as described in claim 4, wherein the cation of the alkylbenzene sulfonate comprises at least one of ammonium, substituted ammonium, an alkaline earth metal or a mixture thereof.

7. The surfactant composition as described in claim 6, wherein the alkali metal comprises sodium.

8. The surfactant composition as described in claim 4, wherein the ethylene oxide / propylene oxide block copolymer has an ethylene oxide content greater than 15% to 70% by weight of the copolymer molecule.

9. The surfactant composition as described in claim 4, wherein the ethylene oxide / propylene oxide block copolymer has an ethylene oxide content of 20% to 70% by weight of the copolymer molecule.

10. The surfactant composition as described in claim 4, wherein the alkylbenzene sulfonate is present in an amount of 15% to 30% by total weight of the composition, and wherein the ethylene oxide / oxide solubility improver of propylene is present in an amount of 0.8% to 8% by total weight of the composition.

11. The surfactant composition as described in claim 4, which has a reduction in the point of transparency of between 5 ° C and 35 ° C when compared to a similar surfactant composition which appears to have at least one solubility enhancer. ethylene oxide / propylene oxide block copolymer.

12. A surfactant composition, comprising a solvent, a solubility enhancer of ethylene oxide / propylene oxide and a linear alkyl benzene sulfonate, the linear alkyl benzene sulfonate has a 2-phenyl isomer content of 14% to 25% by weight; and wherein the alkylbenzene sulfonate is present in an amount of 2% to 40% by total weight of the composition; wherein the ethylene oxide / propylene oxide solubility improver is present in an amount of 0.2% to 10% by total weight of the composition; wherein the ethylene oxide / propylene oxide block copolymer has an ethylene oxide content greater than 15% to 80% by weight of the copolymer molecule; wherein the solvent is present in an amount of 97.8% to 50% by total weight of the composition; wherein the surfactant composition is an aqueous solution; wherein the ethylene oxide / propylene oxide block copolymer has the formula: H3 and HO [CH2CH20] x [CH2CHO] and [CH2CH2O] ZH where x is between 3.5 and 150, and is between 16 and 70, and z is between 3.5 and 150.

13. The surfactant composition as described in claim 12, wherein the ethylene oxide / propylene oxide block copolymer has an ethylene oxide content of 20% to 70% by weight of the molecule.

14. The surfactant composition as described in claim 12, wherein the solvent comprises at least one of water, alcohol, glycol, glycol ether or a mixture thereof.

15. The surfactant composition as described in claim 14, wherein the solvent comprises at least one of water, alcohol having 1 to 6 carbon atoms or a mixture thereof.

16. The surfactant composition as described in claim 12, wherein the alkyl chain of the alkylbenzene sulfonate surfactant contains from 8 to 16 carbon atoms.

17. The surfactant composition as described in claim 12, wherein the cation of the alkylbenzene sulfonate surfactant comprises sodium.

18. The surfactant composition as described in claim 12, wherein the cloud point of the surfactant composition is from 17 ° C to -10 ° C.

19. The surfactant composition as described in claim 12, wherein the point of transparency of the surfactant solution from 23 ° C to -5 ° C.

20. The surfactant composition as described in claim 12, which has a reduction in the cloud point of between 10 ° C and 38 ° C when compared to a similar surfactant composition that appears to be of the oxide block copolymer solubility improver. ethylene / propylene oxide.

21. The surfactant composition as described in claim 12, which has a reduction in the cloud point of between 5 ° C and 35 ° C when compared to a similar surfactant composition that looks like the block copolymer solubility improver. ethylene oxide / propylene oxide.

22. A method for improving the solubility of alkylbenzene sulfonate in a solvent, the method comprising: preparing a liquid solution comprising alkylbenzene sulfonate, the solvent and a block copolymer of ethylene oxide / propylene oxide; wherein the ethylene oxide / propylene oxide block copolymer has an ethylene oxide content greater than 15% by weight of the molecule; wherein the alkylbenzene sulfonate has a 2-phenyl isomer content of less than or equal to 25% by weight; and wherein the solvent comprises water; and wherein the liquid solution has a point of transparency less than or equal to about 20 ° C.

23. The method as described in claim 22, wherein the ethylene oxide / propylene oxide block copolymer has the formula: CH3 and HO [CH2CH20] [CH2CHO] and [CH2CH2O] ZH where x is between 3.5 and 150, and is between 16 and 70, and z is between 3.5 and 150.

24. The method as recited in claim 23, wherein the alkylbenzene sulfonate includes alkylbenzene sulfonates having a 2-phenyl isomer content of 14% to 25% by weight.

25. The method as described in claim 23, wherein the alkylbenzene sulfonate has a 2-phenyl isomer content of up to about 20% by weight.

26. The method as described in claim 24, wherein the alkylbenzene sulfonate alkyl chain has from 8 to 16 carbon atoms.

27. The method as described in claim 24, wherein the cation of the alkylbenzene sulfonate comprises sodium.

28. The method as described in claim 24, wherein the ethylene oxide / propylene oxide block copolymer has an ethylene oxide content greater than 15% to 80% by weight of the copolymer molecule.

29. The method as described in claim 24, wherein the ethylene oxide / propylene oxide block copolymer has an ethylene oxide content of 20% to 80% by weight of the copolymer molecule.

30. The method as described in claim 24, wherein the ethylene oxide / propylene oxide block copolymer has an ethylene oxide content of 20% to 70% by weight of the copolymer molecule.

31. The method as described in claim 24, wherein the preparation comprises preparing a liquid solution with a sufficient amount of ethylene oxide / propylene oxide block copolymer to result in a solution comprising 2% to 40% by weight total of the alkylbenzene sulfonate solution having a 2-phenyl isomer content of 14% to 25% by weight, - and 0.2% to 8% of ethylene oxide / propylene oxide block copolymer by total weight of the solution.

32. The method as described in claim 24, wherein the preparation comprises: adding an ethylene oxide / propylene oxide to the liquid solution, and decreasing the cloud point of the liquid solution from 17 ° C to -10 °. C or decrease the transparency point of the liquid solution from 23 ° C to -5 ° C.

33. The method as described in claim 24, wherein the preparation comprises: adding an ethylene oxide / propylene oxide to the liquid solution; and decrease the turbidity point of the liquid solution between 10 ° C and -7 ° C; or reduce the point of transparency of the liquid solution between 10 ° C and -1 ° C.

34. A surfactant composition comprising: at least one linear alkyl benzene sulfonate having a 2-phenyl isomer content of 14% to 25% by weight; at least one solvent; and at least one solubility improver of ethylene oxide propylene oxide block copolymer; wherein the ethylene oxide / propylene oxide block copolymer has an ethylene oxide content greater than 15% by weight of the molecule; wherein the surfactant composition is an aqueous solution; and wherein the ethylene oxide / propylene oxide block copolymer solubility improver is present in an amount effective to lower the cloud point of the surfactant composition by less than 5 ° C.

35. The surfactant composition as described in claim 34, wherein the ethylene oxide / propylene oxide block copolymer solubility improver is present in an amount effective to lower the cloud point of the surfactant composition unless that or equal to approximately 0 ° C.

36. The surfactant composition as described in claim 34, wherein the ethylene oxide / propylene oxide block copolymer solubility improver is present in an amount effective to lower the cloud point of the surfactant composition of less from 5 ° C to -9.9 ° C.

37. The surfactant composition as described in claim 34, wherein the ethylene oxide / propylene oxide block copolymer solubility improver is present in an amount effective to lower the cloud point of the surfactant composition of the surfactant. ° C to -5 ° C.

38. The surfactant composition as described in claim 34, wherein the ethylene oxide / propylene oxide block copolymer solubility improver is present in an amount effective to lower the cloud point of the surfactant composition of less from 0 ° C to -9.9 ° C.

39. The surfactant composition as described in claim 36, wherein the linear alkylbenzene sulfonate has a 2-phenyl isomer content of 14% to 25% by weight is present in an amount of 2% to 40% by total weight of the composition, wherein the ethylene oxide / propylene oxide block copolymer solubility improver is present in an amount of 0.2% to 10% by total weight of the composition; and wherein a solvent is present in an amount of 50% and 97.8%.