Patent Description:
Another application for bio-based polyacids is in the production of new biobased surfactants for areas such as laundry detergent, personal care, cleaners, and oil field applications.

Laundry detergent surfactants are also referred to as "surface-active agents. " Surfactants are ingredients in detergents and many other high-volume products. Surfactants have unique properties which allow the ingredient to be compatible with water and at the same time be attracted to organic materials, such as grease and dirt. Surfactants perform a balancing act of being attracted to the grease and dirt (lipophilic) while also being attracted to water (hydrophilic). Water alone will not adequately clean the laundry. The lipophilic tail is attracted to the grease and dirt while the hydrophilic head group is attracted to the water. The surfactant suspends the grease and dirt in the water so that it can be rinsed away. Therefore, the surfactant performs the primary cleaning function for a laundry detergent.

There are four categories of surfactants: anionic, nonionic, cationic, and amphoteric.

Anionic surfactants are the largest group, accounting for approximately <NUM>% of the world's surfactant production. These products exhibit superior wetting and emulsifying properties and tend to be higher-foaming materials. Fatty acid soaps and alkylbenzene sulfonates fall into this category. Fatty acid soaps typically have a hydrophilic-lipophilic balance (HLB) of approximately <NUM>, which means they function more as a cleaning agent than as a surfactant. Alkylbenzene sulfonates are petroleum based and do not biodegrade under anaerobic conditions.

Nonionic surfactants are the second largest group by a volume at about <NUM>% of the world's surfactant manufacture. Alcohol ethoxylates fall into this category. Although ethoxylates have a wide range of potential HLB values, products such as alkylphenol ethoxylate are an environment concern due to the production of toxic byproducts from biodegradation.

Cationic surfactants typically have excellent antibacterial properties, provide good corrosion protection, and can be good demulsifiers. Quaternary ammonium compounds and pyridines fall into this category.

Finally, amphoteric surfactants can behave as a cation or anion depending on pH. These surfactants, for example phosphatides, such as lauroamphoacetates, have low reactivity with other materials and are increasingly used in personal care products such as baby shampoo and facial cleanser.

The two surfactants of most interest in laundry detergents are anionic and nonionic because they represent almost <NUM>% of the world's production of surfactants.

Therefore, there remains a need for alternate surfactants.

<CIT> discloses nonionic-anionic mixtures of surface-active agents which may be dissolved in oily materials. <CIT> discloses fluid resins prepared from epoxidized unsaturated fatty acids or esters.

Broadly, methods for the conversion of biobased oils to generate highly functionalized surfactants for various applications are described. Methods to utilize epoxidized vegetable oils (e.g. soybean oil, olive oil, canola oil, sunflower oil), animal oils (e.g., tallow or fish oils), algal oils, or mixtures of free fatty acid esters (e.g., mixtures of individual fatty acid esters or combinations of various feedstocks of fatty acid esters) as a platform chemical to produce a wide array of surfactants with unique functionalities have been developed. The chemistry can be applied generally to any fatty acid-based feedstock, but is generally more advantageous with oils high in oleic acid content.

High oleic soybean fatty acid derivatives can perform well as surfactants in laundry detergent applications. The high oleic soybean oil (HOSO) surfactants developed provide improved formulations and performance in laundry applications. They are also anticipated to have better environmental sustainability with increased biodegradability.

One aspect of the invention is a method for producing a fatty acid based surfactant in accordance with claim <NUM>.

In some embodiments, the fatty acid ester epoxide is reacted with the hydroxy acid or hydroxy ester and wherein the hydroxy acid or hydroxy ester is a biobased hydroxy acid or hydroxy ester.

In some embodiments, the fatty acid ester epoxide is reacted with the hydroxy ester and wherein the hydroxy ester contains an alkyl group having <NUM> to <NUM> carbon atoms.

In some embodiments, the fatty acid ester epoxide is reacted with the hydroxy acid or the hydroxy ester and the hydroxy acid comprises one or more of citric acid, malic acid, lactic acid, glycolic acid, or tartaric acid, or the hydroxy ester comprises one or more of triethyl citrate, trimethyl citrate, diethyl malate, dimethyl malate, ethyl lactate, methyl lactate, ethyl glycolate, methyl glycolate, ethyl tartrate, or methyl tartrate.

In some embodiments, the fatty acid ester epoxide is formed by epoxidizing a fatty acid ester.

In some embodiments, the fatty acid ester epoxide is derived from a high oleic oil or a mid-oleic oil.

In some embodiments, the fatty acid ester epoxide is derived from one of more of high oleic soybean oil, high oleic algal oil, high oleic olive oil, high oleic canola oil, or high oleic sunflower oil.

In some embodiments, the fatty acid ester epoxide comprises one or more of epoxidized methyl oleate, epoxidized methyl soyate, epoxidized <NUM>-decenoic acid methyl ester, epoxidized soybean oil, epoxidized algal oil, epoxidized algal oil methyl ester, epoxidized olive oil, epoxidized canola oil, or epoxidized sunflower oil.

Another aspect of the invention is a fatty acid based surfactant comprising the reaction product of a fatty acid ester epoxide with a hydroxy ester.

In some embodiments, the hydroxy acid comprises one or more of citric acid, malic acid, lactic acid, glycolic acid, or tartaric acid, or the hydroxy ester comprises one or more of triethyl citrate, trimethyl citrate, diethyl malate, dimethyl malate, ethyl lactate, methyl lactate, ethyl glycolate, methyl glycolate, ethyl tartrate, or methyl tartrate.

Another aspect of the disclosure (not claimed) is a method of making a citric acid derived surfactant. The method may comprise reacting an alkyl oxide with a citric acid trialkyl ester in the presence of a tetrafluoroborate catalyst. The citric acid trialkyl ester may contain an alkyl group having <NUM> to <NUM> carbon atoms. The alkyl oxide may comprise one or more of ethylene oxide, propylene oxide, butylene oxide, or butadiene diepoxide.

Replacement of anionic and nonionic surfactants in liquid laundry detergent formulations is one application. However, the same chemistry can be used to produce surfactants for other applications, such as cationic surfactants. Initial evaluation for the surfactants was done in stain removal testing. Anionic surfactants are useful in laundry detergents as they tend to foam, form solids when dry, and produce micelles. Nonionic surfactants tend to be viscous liquids and are excellent in removing oil-based stains.

Alternatives based on the reaction of fatty acid ester epoxides with hydroxylated poly-carboxylic acid esters such as triethyl citrate have been produced.

By biobased oils, we mean vegetable oils, animal fats, or algal oils having at least one triglyceride backbone, wherein at least one fatty acid has at least one double bond.

By fatty acid esters, we mean fatty acids that have been either esterified after steam splitting or hydrolysis of a triglyceride oil or transesterified from a biobased oil. The fatty acids and esters tend to be mixtures of the fatty acids in the parent oil.

By high oleic oil, we mean an oil with a fatty acid composition where the oleic content is in a range of <NUM>-<NUM> wt %. Examples of high oleic oils include, but are not limited to, high oleic soybean oil, high oleic algal oil, olive oil, high oleic canola oil, and high oleic sunflower oil. By mid-oleic oil, we mean an oil with a fatty acid composition where the oleic content is in a range of <NUM>-<NUM> wt %.

By epoxide, we mean fatty acids or esters that contain an oxirane group at the original olefin site. The epoxidation step can be performed before or after transesterification of the triglyceride backbone.

By hydroxy ester, we mean the ester of hydroxy acids. Examples of hydroxy esters include, but are not limited to, triethyl citrate, trimethyl citrate, diethyl malate, dimethyl malate, ethyl lactate, methyl lactate, ethyl glycolate, methyl glycolate, ethyl tartrate, and methyl tartrate. These esters may also have alkyl chains from C<NUM>-C<NUM>.

By hydroxy acid, we mean hydroxy acids. Examples of hydroxy acids include, but are not limited to, citric acid, malic acid, lactic acid, glycolic acid, and tartaric acid.

By polyamine, we mean a structure that contains diamine or greater. Examples of polyamines include, but are not limited to, ethylene diamine, diethylene triamine, spermidine, spermine, triethylene tetramine, tris (<NUM>-aminoethyl)amine, and diaminohexane.

By polyoxyalkyl diol, we mean a diol with an oxyalkyl repeating unit. Example of polyoxyalkyl diols include, but are not limited to, diethylene glycol, triethylene glycol, poly(ethylene glycol), dipropylene glycol, tripropylene glycol, and poly(propylene glycol).

There has recently been great interest in the development of bio-based surfactants for uses from laundry detergents builders (chelators) to oil field applications. One known bio-based chelator is citric acid which has been used for many years to "soften" hard water. However, citric acid is water soluble and requires the addition of a non-polar compound to create a surfactant for other applications. In the past, this has been a problem due to the low reactivity of the tertiary hydroxyl of citric acid. Utilizing salts of tetrafluoroborate allows for the fast and effective reaction of hydroxy acid esters, such as citric and lactic, with epoxides such as epoxidized soybean oil and propylene oxide. Other typical epoxide catalysts, including but not limited to, metal hydroxides or metal halides are not encompassed in the claimed method.

The approach for synthesizing bio-based hydroxy acids such as citric acid derived detergent builders and surfactants is to build molecular weight through etherification of the unique hydroxyl while maintaining the poly-acid functionality. The poly-acid functionality works as the main chelator serving to "soften" by dissolving the metal ion in the water. The reason for etherification versus esterification of the hydroxyl is hydrolytic stability. The ether bond is much more hydrolytically stable thereby maintaining the desired structure during storage under basic conditions. An ester bond would hydrolyze quickly under basic conditions. Further, by etherifying a hydroxy acid with a fatty acid, a structure that can perform the dual functions of surfactant and chelation is obtained.

Another advantage in reacting with epoxides is that you can vary the carbon chain length. By placing a non-polar chain onto the poly-acid, the surfactant formed will allow for the potential dissolving of greasy materials that are often the cause for poor laundry cleaning. It will also allow for increased miscibility with less polar reactants. By varying the carbon chain length and various functionalities, the hydrophilic-lipophilic balance (HLB) value can be adjusted. The HLB value is typically used to predict the desired application such as hydrophilic surfactants containing a HLB value range of <NUM>-<NUM>, water dispersible surfactants HLB range of about <NUM>-<NUM>, and hydrophobic surfactants with a HLB range of <NUM>-<NUM>. These applications can be divided further but contain some overlap depending on function. Hydrophilic surfactants can be broken into solubilizers (HLB <NUM>-<NUM>), detergents (HLB <NUM>-<NUM>), and oil/water emulsifiers (HLB <NUM>-<NUM>). Water dispersible surfactants include oil/water emulsifiers (HLB <NUM>-<NUM>), wetting agents (HLB <NUM>-<NUM>), and water/oil emulsifiers (HLB <NUM>-<NUM>). Hydrophobic surfactants include water/oil emulsifiers (HLB <NUM>-<NUM>) and antifoamers (HLB <NUM>-<NUM>).

As discussed above, these processes can be applied to all epoxidized fatty acid esters. However, when reacting the epoxide with hindered or less active hydroxyls, it is more favorable to use high oleic oils as the feedstock because a reactive hydroxyl is formed when an epoxide ring opens as seen in <FIG>. In the case of linoleic oils such as standard soybean oil, this hydroxyl is favored to react intra-molecularly with the second epoxide thereby cyclizing into a tetrahydrofuranyl structure. This cyclization would increase further with oils high in linolenic fatty acid. The cyclization reaction is minimized when using biobased oils high in mono-unsaturated fatty acids.

One of the desired products is produced by reacting a fatty acid ester epoxide (such as epoxidized high oleic soybean methyl ester) with a hydroxy acid (such as lactic acid) or a hydroxy ester (such as ethyl lactate) to produce an acid or a poly-ester with an ether functionality. The ester groups from the original fatty acid ester epoxide and those present on the hydroxy ester is eventually hydrolyzed to the water-soluble salt(s). A second group of products (not claimed) are produced by reacting a fatty acid ester epoxide (such as epoxidized high oleic soybean methyl ester) with a polyoxyalkyl diol (such as triethylene glycol) to produce an ester alcohol with an ether functionality. The ester group from the original fatty acid ester epoxide can optionally be hydrolyzed to the water-soluble salt(s). The water soluble salts from the first and/or second groups of products could optionally be acidified for some applications, if desired. A third group of products (not claimed) are produced by reacting a fatty acid ester epoxide (such as epoxidized high oleic soybean methyl ester) with a polyamine (such as ethylene diamine) to produce a water-soluble surfactant with an amide and amine functionality. The free amine functionalities can optionally be functionalized further by reaction with monohalide carboxylates (such as mono-chloroacetic acid) to produce chelation functionality.

The initial focus was to determine how hydroxy acid soyate surfactants (those shown in <FIG>, and <FIG>) performed in stain removal testing. A standard formulation was obtained, and various amounts of the anionic and nonionic surfactants as seen in Table <NUM>.

Table <NUM> reveals that the hydroxy acid soy-based surfactants are effective in removing similar stains compared with nonionic surfactants. Considering specific individual stains, these surfactants improved removal of coffee, cocoa (standard EMPA <NUM>), blood and milk (standard EMPA <NUM>), and red wine stains while showing lower performance in the removal of dust sebum, grass, and make-up stains. These results, combined with other testing, determined that specific functional groups on the fatty acid may be needed depending on the specific use. Grass and make-up stains require sulfonate functionality. For this reason, candidates were produced from high oleic soybean oil that contained both mono- and di-sulfonate functionality as seen in <FIG>, <FIG>, <FIG>, and <FIG>. Dust sebum was found to correlate to the fatty acid ethoxylate present in the formulation. Candidates were then synthesized by reacting triethylene glycol or polyethylene glycol <NUM> (PEG <NUM>) with epoxidized high oleic methyl soyate (<FIG>). This process could be used with any molecular weight of polyethylene glycol; however, purification would become more difficult with increased molecular weight.

Another alternative functionality is in the production of amines (not claimed here). Amines can facilitate pH control and removal of fatty acid ester-based stains. The reaction of diethylene triamine (<FIG>) or ethylene diamine with epoxidized high oleic methyl soyate allows to produce amine type functionality. This amine functionality can be further reacted with chloroacetic acid to produce a surfactant with builder functionality (<FIG>).

Finally, most of these reactions can be run by starting with epoxidized triglycerides (as seen in Example <NUM>), but the final formulations will usually include glycerol. The epoxidation of the triglyceride is well known and follows the same procedure seen in Example <NUM>. Epoxidized methyl ester was used as a convenience to faster reaction times and easier analysis to verify complete reactions. Epoxidized methyl ester can be produced by epoxidizing the methyl ester, or transesterifying epoxidized triglycerides with methanol. Various combinations of epoxidized esters may be used.

All examples herein are merely illustrative of typical aspects of the invention and are not meant to limit the invention in any way.

This example shows a procedure for transesterification of high oleic soybean oil with methanol (<FIG>).

<NUM> (<NUM> mol) high oleic soybean oil was added to a flask containing <NUM> methanol and <NUM> sodium methoxide. The mixture was heated to reflux for <NUM> hours. The mixture was partitioned with <NUM> <NUM>% brine and <NUM> ethyl acetate. The ethyl acetate was rinsed with a second aliquot of brine and dried with magnesium sulfate. The mixture was filtered, and the solvent was removed by rotovap followed by vacuum at <NUM> at <NUM> Hg for <NUM> hour. The methyl ester product was verified by NMR analysis.

This example shows a procedure for epoxidation of high oleic methyl soyate (<FIG>).

<NUM> (<NUM> mol) high oleic methyl soyate was added to a flask containing <NUM> (<NUM> mol) formic acid and heated to <NUM>. <NUM> (<NUM> mol) <NUM>% hydrogen peroxide was weighed into an addition funnel. The hydrogen peroxide was added dropwise over <NUM> minutes and a heating mantle and ice-water bath were used to maintain a temperature range of <NUM>-<NUM>. After <NUM> hours, the reaction was <NUM>% complete. <NUM> more <NUM>% hydrogen peroxide were added, and the temperature was held for <NUM> hours longer. Complete reaction was verified by NMR. The mixture was dissolved into ethyl acetate and transferred to a separatory funnel. The water layer was removed. The ethyl acetate layer was rinsed with saturated sodium bicarbonate until the pH of the water layer became basic. The ethyl acetate layer was dried with magnesium sulfate, filtered, and the solvent was removed by vacuum at <NUM> at <NUM> Hg for <NUM> hours.

This example shows a procedure for making alkoxylated triethyl citrate (<FIG>).

<NUM> (<NUM> mol) of triethyl citrate was added to a flask with stirbar and <NUM> (<NUM> mol) of propylene oxide. A condenser was attached followed by addition of <NUM> of copper (II) tetrafluoroborate. The reaction was immediately exothermic and began refluxing. The temperature was held at <NUM> externally for <NUM> hour. NMR analysis revealed complete functionalization of the citrate hydroxyl group.

This example shows a procedure for making the etherified product of triethyl citrate and epoxidized methyl oleate.

<NUM> (<NUM> mol) of epoxidized methyl oleate was mixed in a reactor with <NUM> (<NUM> mol) of triethyl citrate and heated to <NUM>. <NUM> of copper (II) tetrafluoroborate was dissolved into <NUM> (<NUM> mol) of triethyl citrate and added to the reactor. The reaction was immediately exothermic and reached a maximum temperature of <NUM>. The reaction was analyzed after <NUM> hour by proton NMR and shown to be nearly complete. The reaction was stopped after <NUM> hours of total reaction time.

<NUM> (<NUM> mol) of epoxidized methyl oleate was mixed in a reactor with <NUM> (<NUM> mol) of triethyl citrate and heated to <NUM>. <NUM> of copper (II) tetrafluoroborate was dissolved into <NUM> (<NUM> mol) of triethyl citrate and added to the reactor. The reaction was immediately exothermic and reached a maximum temperature of <NUM>. The reaction was stopped after <NUM> hours of total reaction time.

This example shows a procedure for making the etherified product of ethyl lactate and epoxidized methyl soyate (<FIG>).

<NUM> (<NUM> mol) of epoxidized methyl soyate was weighed into a flask containing <NUM> (<NUM> mol) of ethyl lactate and heated to <NUM>. <NUM> of iron (II) tetrafluoroborate was dissolved into <NUM> (<NUM> mol) of ethyl lactate and added to the reactor. The reaction was immediately exothermic and reached a maximum temperature of <NUM>. The reaction was stopped after <NUM> hours of total reaction time.

This example shows a procedure for making the etherified product of diethyl malate and epoxidized high oleic methyl soyate and converting to a final laundry surfactant form.

<NUM> (<NUM> mol) of epoxidized high oleic methyl soyate was weighed into a flask containing <NUM> (<NUM> mol) of diethyl malate and heated to <NUM>. <NUM> of iron (II) tetrafluoroborate was dissolved into <NUM> (<NUM> mol) of diethyl malate and added to the reactor. The reaction was immediately exothermic and reached a maximum temperature of <NUM>. The reaction was stopped after <NUM> hours of total reaction time. The product was passed through a bed of basic alumina. Excess diethyl malate was removed by vacuum at <NUM> and <NUM> Hg for <NUM> hours resulting in an ether-triester oil.

<NUM> (<NUM> mol) sodium hydroxide was dissolved into <NUM> of water heated to <NUM>. <NUM> (<NUM> mol ester) of the ether-triester oil was added dropwise over <NUM> minutes. The mixture was thickening, so <NUM> more water was added. NMR spectroscopy revealed hydrolysis of the esters to carboxylate salts.

This example shows a procedure for making the etherified product of triethylene glycol and epoxidized high oleic methyl soyate and converting to a final laundry surfactant form. This process was also repeated with PEG <NUM> to produce a second ethoxylate ether.

<NUM> (<NUM> mol) of epoxidized high oleic methyl soyate was weighed into a flask containing <NUM> (<NUM> mol) of triethylene glycol and heated to <NUM>. <NUM> of copper (II) tetrafluoroborate was dissolved into <NUM> (<NUM> mol) of triethylene glycol and added to the reactor. The reaction was slowly exothermic and reached a maximum temperature of <NUM> but was two phases. After <NUM> minutes, the temperature was raised to <NUM> after which the reaction was exothermic to a maximum of <NUM>. Reaction was complete after <NUM> hour. The oil was dissolved into ethyl acetate and partitioned three times with water. The ethyl acetate was dried with magnesium sulfate. This process was repeated a second time to increase the mass available. The runs were combined and filtered through a medium frit. Excess ethyl acetate was removed by vacuum first in a rotovap and second at <NUM> and <NUM> Hg resulting in a yellow ether-monoester oil. NMR spectroscopy verified production of the water insoluble product.

<NUM> (<NUM> mol) sodium hydroxide was dissolved into <NUM> of water and added to <NUM> (<NUM> mol ester) of the ether-monoester oil. The temperature was raised to <NUM> for <NUM> hours. IR confirmed only trace ester was present. The reaction was run <NUM> minutes longer at <NUM>. The final water-soluble product was stored in a jar. Example <NUM> (reference example).

This example shows a procedure for making an amine functional product of diethylene triamine (DET) and epoxidized high oleic methyl soyate.

<NUM> (<NUM> mol) of DET was weighed into a flask and heated to <NUM>. <NUM> (<NUM> mol) of epoxidized high oleic methyl soyate was weighed into an addition funnel and added dropwise over <NUM> minutes to the warm DET with stirring for <NUM> hours. Only a small amount reacted, so the temperature was raised to <NUM> for <NUM> hours and then to <NUM> for <NUM> hours more. NMR revealed <NUM>% of the epoxy had reacted and <NUM>% of the methyl ester had amidified. <NUM> (<NUM> mol) DET was added, and the mixture was heated to <NUM> for <NUM> hours, followed by <NUM> for <NUM> hours. Reaction was then complete. Excess DET was removed by vacuum at 90C and <NUM> Hg for <NUM> hours, resulting in a water-soluble amine functional oil.

This example shows a procedure for further functionalizing the product from Example <NUM>.

<NUM> (<NUM> mol) of amine functional oil was added to a flask containing <NUM> (<NUM> mol) sodium hydroxide and <NUM> water. <NUM> (<NUM> mol) chloroacetic acid was then added slowly. The temperature was held at <NUM> for <NUM> hours. NMR analysis supported the addition of carboxymethyl functionalization.

This example shows an alternative approach to produce the surfactant in Example <NUM>.

<NUM> (<NUM> mol) of epoxidized high oleic soybean oil was added to <NUM> (<NUM> mol) diethylene triamine and heated with stirring to <NUM>. The reaction was held for <NUM> hours. The amidification was verified by IR. The water-soluble product was verified by NMR analysis.

This example shows a procedure for the amidification of high oleic soybean fatty acids with an aromatic amine.

<NUM> (<NUM> mol) high oleic soybean fatty acid was added to a reactor containing <NUM> (<NUM> mol) aniline and heated with stirring to <NUM>. After <NUM> hours, <NUM> more aniline was added to the reactor. At <NUM> hours, the reaction was <NUM>% complete. The reactor was heated to <NUM> with <NUM> SCFH argon headspace flow to distill excess aniline. The remainder of aniline was then removed by vacuum at <NUM> at <NUM> Hg for <NUM> hours.

This example shows a procedure for the sulfonation of the aromatic amide produced in Example <NUM>.

<NUM> (<NUM> mol) of the aniline product from Example <NUM> was weighed into a flask. <NUM> (<NUM> mol) of fuming sulfuric acid, <NUM>% trioxide was added dropwise while controlling the temperature below <NUM>. Once addition was complete, the reaction was held at <NUM> for <NUM> hours. NMR analysis supported the sulfonated aromatic amide structure.

This example shows an alternative procedure to produce the surfactant produced in Example <NUM>.

<NUM> (<NUM> mol) high oleic methyl soyate was weighed into a flask with <NUM> (<NUM> mol) sulfanilic acid sodium salt and <NUM> N-methylpyrrolidinone (NMP). The reaction was heated with stirring to <NUM> for <NUM> hours followed by <NUM> for <NUM> hours. The NMP was removed by vacuum distillation.

This example shows a procedure for the reaction of benzylamine with epoxidized high oleic methyl soyate.

<NUM> (<NUM> mol) high oleic methyl soyate was added to an autoclave containing <NUM> (<NUM> mol) benzylamine and <NUM> zinc chloride. The reactor was heated to <NUM> for <NUM> hours, after which IR showed the reaction was nearly complete. <NUM> (<NUM> mol) benzylamine was added and the reaction continued for <NUM> hours more. IR showed complete reaction. The mixture was transferred to a flask and excess benzylamine was removed by vacuum at <NUM> at <NUM> Hg for <NUM> hours. NMR analysis supported the aromatic amide structure.

This example shows a procedure for the sulfonation of the product from Example <NUM>.

<NUM> (<NUM> mol) of the benzylamide product from Example <NUM> was weighed into a flask and heated to <NUM> with stirring. <NUM> (<NUM> mol) of fuming sulfuric acid, <NUM>% trioxide was added dropwise while controlling the temperature at <NUM>. NMR supported the sulfonated amide structure.

Claim 1:
A method for producing a fatty acid based surfactant comprising:
reacting a fatty acid ester epoxide with a hydroxy acid or a hydroxy ester in the presence of a catalyst to produce an acid or a poly-ester with an ether functionality, wherein the catalyst comprises one or more of a tetrafluoroborate salt catalyst, a metal hydroxide catalyst, or a metal halide catalyst; and
hydrolyzing an ester from the fatty acid ester epoxide or the hydroxy ester under basic conditions to form a water-soluble salt.