Bio-based SOY oil-derived quaternary ammonium surfactants

Abstract

A cationic surfactant synthesized from soybean oil (S) and fully hydrogenated soybean oil (FHS), and a method to product the cationic surfactant, is described. The surfactant is produced without the need to separate the different fatty acid components in the mixture. The resulting surfactant exhibits comparable surface activity to cetyltrimethylammonium bromide (C16TAB) and better surface activity than dodecyltrimethylammonium bromide (C12TAB).

Description

BIO-BASED SOY OIL-DERIVED QUATERNARY AMMONIUM SURFACTANTSCross-Reference to Prior Applications

[0001] The present application claims priority to U.S. Provisional Application 63 / 596,435, filed November 6, 2023, currently pending, which is incorporated by reference in its entirety.Background of the InventionField of the Invention

[0002] The presently disclosed subject matter relates to the synthesis and characterization of bio-based quaternary ammonium (QA) surfactants synthesized via a two-step reaction from commercial soybean oil (S) or fully hydrogenated soybean oil (FHS). The products exhibit comparable surface activity to cetyltrimethylammonium bromide (CisTAB) and better surface activity than dodecyltrimethylammonium bromide (C12TAB).

[0003] Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98

[0004] Quaternary ammonium (QA) amphiphiles have been widely investigated as a type of cationic surfactant. Because they are electro-chemically stable and adsorb onto negatively charged surfaces, QA amphiphiles are commonly found in commercial products, such as corrosion inhibitors, fabric softeners, surface treatments, gene transfection agents, and antibacterial agents.

[0005] The most common commercial QA surfactants are petroleum based, and have a simple hydrocarbon tail and a quaternary ammonium group. Recently, interest has grown in bio-based surfactants, including QA amphiphiles. An ideal bio-based QA surfactant for industrial application should have superior or comparable surface activity to petroleum-based surfactants at a reasonable cost.

[0006] The hydrocarbon tail affects surfactant performance. Increasing the tail group length generally reduces the critical micelle concentration (CMC) and improves the surface activity by improving hydrophobicity. However, long saturated tails promote crystallizing of the surfactants and reduce water solubility. For example, a Cl 8 saturated tail is barely soluble in water at room temperature. Surfactants with unsaturated tails typically have better water solubility and lower Krafft points than surfactants with saturated tails, which is a benefit for applications using high surfactant concentrations, but introducing double bonds in the tail reduces the hydrophobicity and increases the CMC thereby reducing surface activity.

[0007] Thus, a challenge for producing a bio-based QA amphiphile surfactant is controlling the tail length and degree of saturation. This challenge is complicated by the complexity of the fatty acid mixtures found in natural oils from any single source. For example, triglycerides of natural soybean oil include linoleic acids, linolenic acids, oleic acids, palmitic acids, and stearic acids, so the resulting bio-based surfactant contains hydrophobic tail groups with different lengths and degrees of saturation.Summary of the Present Invention

[0008] The present development is a cationic quaternary ammonium surfactant having an aliphatic chain from fatty acid groups from soybean oil. The surfactant has the chemical structure A, B, C or D, wherein R = aliphatic chain from fatty acid groups from soybean oil:

[0010] In one embodiment, the aliphatic chain (R) is a C 16 or C18 linear hydrocarbon chain. The aliphatic chain (R) may be selected from alpha-linolenic acid, linolenic acid, oleic acid, stearic acid, palmitic acid, and a combination thereof

[0011] The cationic quaternary ammonium surfactant is synthesized from soybean oil. In one embodiment, the soybean oil is selected from food grade soybean oil (S) or fully hydrogenated soybean oil (FHS).

[0012] The cationic quaternary ammonium surfactant having chemical structure A or B is synthesized from soybean oil and an alkyd polyamine. Representative alkyl polyamines include ethylenediamine (EDA), diethylenetriamine (DETA), spermidine (SPM), and triethylenetetramine (TETA). The surfactant is produced by reacting the soybean oil with the alkyl polyamine, and then alkylating the primary and secondary amine groups with a methylating agent, such as iodomethane, in the presence of N, N-diisopropylethylamine (DIPEA), and collecting the resulting product. In an exemplar}’ embodiment, the soybean oil is reacted with the alkyl polyamine and l,4-diazabicyclo[2,2,2]octane to produce a monosubstituted fatty acid amide, and the mono-substituted fatty’ acid amide is reacted with iodomethane in the presence of N, N-diisopropylethylamine to produce the quaternaryammonium surfactant. The different fatty acid components in the soybean oil do not need to be separated before reaction with the alkyl polyamines.

[0013] The cationic quaternary ammonium surfactant having chemical structure C or D is synthesized from soybean oil and an ether amine. Representative ether amines include 2,2’- (ethylenedioxy)bis(ethylamine) (DO) or 4, 7.10-trioxa-l,13-tri decanediamine (TO). The surfactant is produced by reacting the soybean oil with the ether amine, and then alkylating the primary amine group with a methylating agent, such as iodomethane, in the presence of N, N- diisopropylethylamine (DIPEA), and collecting the resulting product. The different fatty' acid components in the soybean oil do not need to be separated before reaction with the ether amines.

[0014] The resulting surfactant exhibits comparable surface activity to cetyltrimethylammonium bromide (CieTAB) and better surface activity than dodecyltrimethylammonium bromide (C12TAB).Brief Description of the Figures

[0015] FIG. 1 is a set of adsorption isotherms for quaternary' ammonium surfactants synthesized from (a) soybean oil (S) plus DETA or TETA or SPM, (b) fully hydrogenated soybean oil (FHS) plus DETA or TETA or SPM, and (c) commercial surfactants having CIO, C12, and C 16 hydrophobic chain lengths;

[0016] FIG. 2 is a set of FT-IR spectra showing the starting material oil and corresponding fatty acid amide derived from (a) food grade soybean oil and (b) fully hydrogenated soybean oil;

[0017] FIG. 3 is a set of FT-IR spectra showing the quaternary ammonium compounds produced from the fatty acid amides of FIG. 2 starting with (a) food grade soybean oil and (b) fully hydrogenated soybean oil;

[0018] FIG. 4(a) is a 'll-NMR and FIG. 4(b)13C-NMR of the quaternary ammonium surfactants of the present invention; and,

[0019] FIG. 5 is a graph of the zeta potential measurements of the QA surfactant micelles at different pH values;

[0020] FIG. 6 is a set of adsorption isotherms for quaternary' ammonium surfactants synthesized from soybean oil (S) plus DO (“Q-S-DO”) and from soybean oil plus TO (“Q-S- TO”); and,

[0021] FIG. 7 is a set of FT-IR spectra showing the food grade soybean oil (“S”) and corresponding fatty7acid ether amine prepared from DO (“S-DO”) and the quaternary ammonium compounds produced from the fatty acid ether amines prepared from S and DO (“Q-S-DO”) and from S and TO (“Q-S-TO”).Detailed Description of the Present Development

[0022] The details of one or more embodiments of the presently disclosed subject matter are set forth in this document. Modifications to embodiments described in this document, and other embodiments, will be evident to those of ordinary7skill in the art after a study of the information provided in this document. The information provided in this document, and particularly the specific details of the described exemplary7embodiments, is provided primarily for clearness of understanding and no unnecessary limitations are to be understood therefrom. In case of conflict, the specification of this document, including definitions, will control.

[0023] The present development is a cationic surfactant synthesized from soybean oil (S) or fully hydrogenated soybean oil (FHS). In a first embodiment, the surfactant has the chemical structure A:A wherein R = aliphatic chain from fatty acid groups from S or FHS and n = 0 - 2. In a second embodiment, the surfactant has the chemical structure B:B wherein R = aliphatic chain from fatty acid group from S or FHS, x = 3, y = 4 or x = 4, y = 3.In a third embodiment, the surfactant has the chemical structure C:C wherein R = aliphatic chain from fatty acid group from S or FHS. In a fourth embodiment, the surfactant has the chemical structure D:D wherein R = aliphatic chain from fatty acid group from S or FHS. In the surfactant, the aliphatic chain from fatty acid groups from S or FHS are C16 or C18 linear hydrocarbon chains.Examples of fatty acids that may form the aliphatic chains include alpha-linolenic acid, linolenic acid, oleic acid, stearic acid, and palmitic acid.

[0024] The cationic surfactant A or B is produced by reacting soybean oil or fully hydrogenated soybean oil and an alky l polyamine to produce a mono-substituted fatty acid amide (FAAm), as shown in Eq. (a). Representative alkyl polyamines include ethylenediamine (EDA), diethylenetriamine (DETA), and triethylenetetramine (TETA), and spermidine (SPM). As shown in Eq. (b), the primary' and secondary' amine groups in the mono-substituted FAAm are then alkylated with a methylating agent in the presence of N, N-diisopropylethylamine (DIPEA). lodomethane is generally used as the methylating agent with surfactants, but other methylating agents such as bromomethane or agents that include alkyl groups such as dimethyl sulfate, may also be used.

[0025] The cationic surfactant C or D is produced by reacting soybean oil or fully hydrogenated soybean oil and an ether amine to produce a mono-substituted fatty acid amide (FAAm). Representative ether amines include 2,2’-(ethylenedioxy)bis(ethylamine) (DO) or 4,7,10-trioxa-l,13-tridecanediamine (TO). The primary amine group in the mono-substituted FAAm is then alkylated with a methylating agent in the presence of N, N-diisopropylethylamine (DIPEA). lodomethane is generally used as the methylating agent with surfactants, but other methylating agents such as bromomethane or agents that include alky l groups such as dimethyl sulfate, may also be used.

[0026] The bio-based quaternary ammonium (QA) surfactant is produced without the need to separate the different fatty acid components in the mixture. As shown in FIGs. 1 and 6, the resulting surfactant exhibits comparable surface activity to cetyltrimethylammonium bromide (CieTAB) and better surface activity than dodecyltrimethylammonium bromide (C12TAB).

[0027] The preparation of the QA surfactant is achieved using a t o-step process: (a) mono-substituted fatty' acid amides (FAAm) are synthesized, and (b) the FAAm amine headgroups are alkylated. The mono-substituted FAAms are synthesized by catalyzed solvent- free nucleophilic substitution of the triglyceride ester by amine under mild heating.

[0028] Synthesis of mono-substituted fatty acid amide'. A mono-substituted FAAm mixture is synthesized by adding food grade soybean oil (S) or fully hydrogenated soybean oil (FHS), plus 2 mol polyamine or 2 mol ether amine and 0.004 mol l,4-diazabicyclo[2,2,2] octane (DABCO) per fatty acid group of the soybean oil, to a reaction vessel. The polyamine or ether amine is selected from ethylenediamine (EDA), diethylenetriamine (DETA), spermidine (SPM), tri ethylenetetramine (TETA), 2,2’ -(ethylenedi oxy)bis(ethylamine) (DO), or 4,7,10- tri oxa- 1,13-tri decanediamine (TO). The mixture is stirred and heated at about 60°C for about 72 hours. A solid product mixture forms and the solid product mixture is collected by filtration. If necessary, the reaction mixture may be cooled to initiate solid product formation before the filtration step. The solid product mixture is dissolved in hot ethanol (from about 40°C to about 60°C) and then recrystallized at about -10°C to remove the excess amine. The solid is collected and dried with vacuum at 80°C.

[0029] Alkylation of the mono-substituted fatty acid amide'. When produced from soybean oil and a polyamine, the mono-substituted FAAms have primary' and secondary' amine groups.When produced from soybean oil and an ether amine, the mono-substituted FAAms have a primary amine group. The primary and secondary amine groups in the FAAms are alkylated by iodomethane (CH3I) in the presence of N, N-diisopropylethylamine (DIPEA). Acetonitrile (ACN) is used as the solvent for the reaction. For each mole of the amine group, 1 mol DIPEA and 1 ml ACN is added. The mixture is stirred at about 500 rpm for about 1 hour, and then transferred to an ice bath. Approximately 5 mol CH3I is added dropwise (0.5 ml / min) while stirring. The mixture is stored overnight to allow a solid to form. The solid is collected, rinsed with acetonitrile, and dried under vacuum at 80°C. After drying the QA surfactant is collected.

[0030] In the mono-substituted FAAm synthesis step, no solvent is used and care must be taken to ensure that the amount of poly amine or ether amine used in the reaction is in excess relative to the fatty' acid groups of the soybean oil or FHS. Excess polyamine or ether amine is used to ensure formation of the mono-substituted structure. In the alkylation step, without being bound by theory, it is believed that the use of DIPEA shifts the equilibria toward complete quatemization.

[0031] The chemical structures of the FAAms and the QA surfactants were characterized by Fourier-transform infrared spectroscopy (FT-IR), proton and carbon-13 nuclear magnetic resonance spectroscopy (1H NMR,13C NMR), surface tension, and the zeta potential of each QA surfactant micelle was measured.

[0032] As shown in FIG. 2 (a, b), FIG. 3 (a,b), and FIG. 7, after the alkylation reaction, the FT-IR spectra includes peaks at 3010 cm-1(yas (N — CH3)), 1400 cm'1(8 N — CH3)), and 903 cm'1(v(C — A / )). In the fingerprint region, bands between 900 and 923 occur, which corresponds to the C — H bending. These results suggest that the FAAms are successfully alkylated with CHsI. The proton NMR and carbon- 13 NMR spectra of the FHS, the synthesized FAAms, and the product after alkylation show peak shifts consistent with transformation from the soybean oil fatty acid groups to a quaternary7ammonium structure, as shown in FIG. 4.

[0033] The interfacial packing and micelle parameters of different quaternary' ammonium surfactants are summarized in Table 1. Surface activity was characterized by collecting the adsorption isotherms of the QA surfactants as shown in FIG. 1 (a), (b), FIG. 6, and of common commercial petroleum-based cationic surfactants with different hydrophobic chain lengths as shown in FIG. 1 (c). Surface tension (SFT) w as measured using pendant drop tensiometry' wi th a KRUSS DSA30 goniometer based on the fitting of the axisymmetric Young-Laplace equation. The surface excess value (T) for each QA surfactant was calculated based on Gibbs adsorption isotherm, and F was used to calculate average headgroup area, which reflects the packing density' of the surfactant molecules at the air / w ater interface.Table 1

[0034] For the commercial surfactants with the same headgroup, increasing hydrophobic chain length from CIO to C16 leads to a smaller headgroup area, lower CMC. and corresponding SFT. A smaller headgroup area usually indicates higher compressibility, an enhanced orientation of the surfactant, and a more densely packed monolayer. This could result in the increased zeta potential as observed.

[0035] The FHS-derived surfactants exhibited similar, or higher surface activity' than CieTAB considering the CMC, headgroup area, and SFT. The interfacial packing and micelleparameters are dependent on the headgroup structure. Among the three FHS-derived samples, the CMC varied from 1.1 to 3.7 mM depending on the polyamine type. The S-derived surfactants exhibited lower surface activity than FHS-derived ones, but are still higher than C12TAB.

[0036] Based on the zeta potential results, all the synthesized products exhibited positive charges above 50 mV, which is comparable to the charge obtained for CieTAB. The positive charge remains in acidic, neutral, and alkaline mediaand confirms that very little unquatemized amines are present. Secondary' and tertian- amines are sensitive to pH and become uncharged in alkaline media, so the zeta potential would vary' by pH if the products were not fully quatemized.

[0037] In general, bringing more quaternary ammonium groups to the headgroup greatly improve the hydrophilicity of C18 components. All the S-derived products exhibited water solubility greater than 50 mM. The solubility of FHS-derived products is around 30 mM at room temperature presumably due to the fully saturated structure and higher Krafft point. At elevated temperature (50 °C), the FHS-derived product solubility increases above 50 mM.

[0038] The composition of the headgroup can affect the surfactant properties and characteristics. For example, adding ethoxylate in the headgroup improves surfactancy and results in a less irritating surfactant. Without being bound by theory, it is believed that long- chain (Cl 8) QA surfactants are made water-soluble at room temperature by introducing two or more quaternary ammonium groups in the headgroup. The water solubility can be further improved by having unsaturated hydrophobic tails.

[0039] The properties of surfactants with homogeneous and heterogeneous tail group saturation were also investigated by using fully hydrogenated soybean oil. Having unsaturation in the tail groups results in slightly lower surface activity compared to saturated tails. The FHSand diethylenetriamine (DETA) product exhibits the highest surface activity, with CMC =1.1 mM and SFT = 32 mN / m. which is lower than that of CieTAB.

[0040] In the present development, cationic QA surfactants that are biobased from soybean oil that are anticipated to biodegrade, have been successfully synthesized via a two-step reaction. The products exhibit comparable, or better, surface activity than commercial QA surfactants (Cio leTAB). Introducing more quaternary7ammonium groups or unsaturated hydrophobic tails are found beneficial for improving the surfactant water solubility. The heterogeneous tail group composition of S-derived products results in slightly poorer surface activity7than FHS-derived products. However, the CMC and lowest SFT are still more competitive than C 12TAB. Among all the products, DETA-derived samples exhibits the highest surface activity'. Further increasing the headgroup charge or using asymmetric polyamines results in a less densely packed interface and higher CMC.

[0041] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary7skill in the art to which the presently disclosed subject matter pertains. All patents, patent applications, published applications and publications, databases, websites and other published materials referred to throughout the entire disclosure herein, unless noted otherwise, are incorporated by' reference in their entirety. Representative methods, devices, chemical structures, reaction schematics, and materials are described herein, but are not intended to be limiting unless so noted.

[0042] Unless otherwise indicated, the specific materials mentioned herein refer to the following materials and sources: ethylenediamine (EDA) (> 99%), diethylenetriamine (DETA) (99 %), spermidine (SPM) (> 99%), tri ethylenetetramine (TETA) (> 97%), 2,2’- (ethylenedioxy)bis(ethylamine) (> 98%), 4,7,10-trioxa-l,13-tridecanediamine (> 97%), N, N- diisopropylethylamine (DIPEA) (> 99%), iodomethane (CH3I) (> 99%), decyltrimethylammonium bromide (C10TAB) (> 98%). dodecyltrimethylammonium bromide(C12TAB) (98%), cetyltrimethylammonium bromide (CieTAB) (> 99%), 1,4- diazabicyclo[2,2,2]octane (DABCO). dimethyl sulfoxide-d6 (DMSO) (99.9 atom % D, contains 0.03% (v / v) TMS), purchased from Sigma-Aldrich; ethyl alcohol (200 proof, anhydrous), purchased from Decon Labs, Inc; food grade soybean oil purchased from Kroger Co.; fully hydrogenated soybean oil received from ADM James R. Randall Research Center. All chemicals were used as received.

[0043] Unless otherwise indicated, the FT-IR spectra were collected using a Perkin Elmer Spectrum Q100 spectrometer. Each sample was scanned between 4000 ~ 600 cm'1wavelength range. Each spectrum reported is an average of 10 scans.

[0044] Unless otherwise indicated, the NMR spectra were collected using a Bruker Advanced DRX-500 spectrometer. All the measurements were carried out at room temperature with DMSO-d6 as the solvent.

[0045] Unless otherwise indicated, the zeta potential of each QA surfactant micelle was measured with a Malvern Zetasizer Nano ZS. The QA surfactant solution was prepared with DI water at a concentration of 15 rnM. The solution was stirred overnight before measurements. The electrical charge on the molecule was investigated by measuring the zeta potential of the surfactant micelles at different pH values (4 ~ 12). Each reported value was an average of 30 measurements at room temperature.

[0046] Unless otherwise indicated, the surface tension was measured by dissolving the surfactants in DI water and stirring overnight. Surface tension (SFT) measurements were made using pendant drop tensiometry with a KRUSS DSA30 goniometer based on the fitting of the axisymmetric Young-Laplace equation. Each value reported was an average of 3 tests. The surface excess (F) for each QA surfactant was calculated based on Gibbs adsorption isotherm (Eq. l). With the surface excess values, the average headgroup area (Ao) was calculated usingEq. 2 in AQ. This value reflects the packing density of the surfactant molecules at the air / water interface.In the equations, y represents the interfacial tension, C is the surfactant molar concentration, T is the temperature in Kelvin, R is the universal gas constant, and NAis Avogadro’s number, n is the number of components constituting the surfactant adsorbed at the surface, n = 2 is used considering the cationic nature of the QA surfactants.

[0047] The terms “a”, “an”, and “the” refer to “one or more” when used in the subject specification, including the claims. Thus, for example, reference to “an amine group” includes a plurality of such groups, and so forth. The term “ambient temperature” as used herein refers to an environmental temperature of from about 0°F to about 120°F, inclusive.

[0048] Unless otherwise indicated, all numbers expressing quantities of components, conditions, and otherwise used in the specification and claims are to be understood as being modified in all instances by the term “about”. Accordingly, unless indicated to the contrary, the numerical parameters set forth in the instant specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by the presently disclosed subject matter.

[0049] As used herein, the term “about”, when referring to a value or to an amount of mass, weight, time, volume, concentration, or percentage can encompass variations of, in some embodiments ± 20%, in some embodiments ± 10%, in some embodiments ± 5%, in some embodiments ± 1%, in some embodiments ± 0.5%, and in some embodiments to ± 0.1%. from the specified amount, as such variations are appropriate in the disclosed application.

[0050] As used herein, ranges can be expressed as from “about"’ one particular value, and / or to “about” another particular value. It is also understood that there are a number of values disclosed herein, and that each value is also herein disclosed as “about” that particular value in addition to the value itself. For example, if the value “10” is disclosed, then “about 10” is also disclosed. It is also understood that each unit betw een two particular units are also disclosed. For example, if 10 and 15 are disclosed, then 11, 12, 13, and 14 are also disclosed.

[0051] All compositional percentages used herein are presented on a “by weight” basis, unless designated otherwise.

[0052] It is understood that, in light of a reading of the foregoing description, those with ordinary skill in the art will be able to make changes and modifications to the present invention without departing from the spirit or scope of the invention, as defined herein. For example, those skilled in the art may substitute materials supplied by different manufacturers than specified herein without altering the scope of the present invention.

Claims

ClaimsWhat is claimed is:

1. A composition having the chemical structure A, wherein R = aliphatic chain from fatty acid groups from soybean oil and n = 0 - 2:

2. A composition having the chemical structure B, wherein R = aliphatic chain from fatty acid groups from soybean oil and x = 3, y = 4 or x = 4, y = 3:

3. A composition having the chemical structure C or D, wherein R = aliphatic chain from fatty7acid groups from soybean oil:

4. The composition of Claim 1, Claim 2. or Claim 3 wherein the aliphatic chain (R) is aC16 or C18 linear hydrocarbon chain.

5. The composition of Claim 4 wherein the aliphatic chain (R) is selected from alphalinolenic acid, linolenic acid, oleic acid, stearic acid, palmitic acid, and a combination thereof.

6. The composition of any of Claims 1 - 5 wherein the composition is prepared by reacting soybean oil and an alkyl polyamine or an ether amine.

7. The composition of Claim 6 wherein the soybean oil is selected from food grade soybean oil or fully hydrogenated soybean oil.

8. The composition of Claim 6 wherein the alkyl polyamine is selected from the group consisting of ethylenediamine (EDA), diethylenetriamine (DETA), spermidine (SPM), and triethylenetetramine (TETA).

9. The composition of Claim 6 wherein the ether amine is selected from the group consisting of 2,2’-(ethylenedioxy)bis(ethylamine) and 4,7,10-trioxa-l,13- tridecanediamine.

10. The composition of Claim 5 wherein the soybean oil is reacted with the alkyl poly amine or the ether amine and l,4-diazabicyclo[2,2,2]octane to produce a mono-substituted fatty acid amide, and the mono-substituted fatty acid amide is reacted with iodomethane in the presence of N, N-diisopropylethylamine to produce the quaternary ammonium surfactant.

11. A method for making a quaternary ammonium surfactant comprising the steps:(a) combining soybean oil with at least one polyamine or at least one ether amine and withl,4-diazabicyclo|2,2,2]octane to form a mixture;(b) stirring and heating the mixture to produce a mono-substituted fatty acid amide;(c) collecting the mono-substituted fatty acid amide;(d) combining the mono-substituted fatty acid amide with N. N- diisopropylethylamine in a solvent and stirring;(e) transferring the reaction mixture of step (d) to an ice bath and adding iodomethane dropwise while stirring to alkylate the mono-substituted fatty acid amide;(f) allowing the alkylated the mono-substituted fatty acid amide to form a solid product;(g) collecting the solid product from step (f);(h) washing the collected solid from step (g) and dry ing under vacuum form a quaternary ammonium surfactant; and,(i) collecting the quaternary ammonium surfactant.

12. The method of Claim 11 wherein the soybean oil is selected from food grade soybean oil or fully hydrogenated soybean oil.

13. The method of Claim 11 wherein the alkyl polyamine is selected from the group consisting of ethylenediamine (EDA), diethylenetriamine (DETA), spermidine (SPM), and triethylenetetramine (TETA).

14. The method of Claim 11 wherein the ether amine is selected from the group consisting of 2,2’-(ethylenedioxy)bis(ethylamine) and 4,7,10-trioxa-l , 13-tridecanediamine.

15. The method of Claim 11 wherein no solvent is added in step (a).

16. The method of Claim 11 wherein the mono-substituted fatty acid amide is dried before step (d).

17. The method of claim 11 wherein acetonitrile is used as a solvent in step (d).

18. The method of claim 11 wherein the amount of polyamine used in the reaction is in excess relative to the fatty acid groups of the soybean oil.

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