Products and methods for the treatment of mixtures of water and hydrophobic liquids

Abstract

The invention relates to chemical-based methods and products for mitigating the impact of an oil spill, that act via mechanisms which include reducing adhesiveness, herding, thickening and gelling. N-fatty acid amino acid (FA-AA) conjugates display oil-herding behavior when formulated as a salt, or the free acid in water-miscible organic solvents. Various salts of FA-AA conjugates are water soluble and can herd oils and increase the thickness of the oil layer. Replacement of the acid group of fatty acid α-amino acid conjugates with other groups that act as hydrogen bond donors and acceptors results in potent phase selective organo gellants. The oil thickeners or gellants include can be prepared from biobased feedstocks, have low toxicity, high capacity for oil and reduction of the need to use an organic solvent to apply the thickener or gellant to an oil and water mixture in order to gel the oil phase. ##STR00001##

Claims

1. A composition for treating a mixture of oil and water to herd the oil, comprising a water-miscible organic solvent and one or more compounds of Formula IB: ##STR00031## where: R.sub.1 is selected from the group consisting of: ##STR00032## and R.sub.2 is selected from the group consisting of saturated and unsaturated C.sub.5 to C.sub.21 linear hydrocarbon chains.

2. A composition according to claim 1, wherein the compound is stearoyl alanine.

3. A composition according to claim 1, wherein the compound is lauroyl alanine.

4. A composition according to claim 1, wherein the compound is myristoyl phenylalanine.

5. A composition for treating a mixture of oil and water to herd the oil on the surface of the water, comprising L-Alanine, N-(1-oxododecyl)-, sodium salt or its enantiomer or the racemic mixture, L-Phenylalanine, N-(1-oxododecyl)-, sodium salt or its enantiomer or the racemic mixture, L-Phenylalanine, N-(1-oxotetradecyl)-, sodium salt or its enantiomer or the racemic mixture, or L-tyrosine, N-(1-oxohexadecyl)-, sodium salt or its enantiomer or the racemic mixture.

6. A composition according to claim 1, further comprising a water-soluble delivery solvent.

7. A composition for treating a mixture of oil and water to gel or increase the viscosity of the oil on the surface of the water, comprising one of: ##STR00033## and (S)—N-(1-aminol-1-oxopropan-2-yl)dodecanamide.

8. A composition for treating a mixture of oil and water to thicken or gel the oil on the surface of the water, comprising a compound of Formula III: ##STR00034## where: R.sub.1 is selected from the group consisting of saturated and unsaturated C.sub.5 to C.sub.21 linear hydrocarbon chains; G is selected from the group consisting of —OH, —NH.sub.2, —NHNH.sub.2, —NOH, —NOCH.sub.3, and —N(CH.sub.2).sub.2OH; and n is =2.

9. A composition for treating a mixture of oil and water to thicken or gel the oil on the surface of the water, comprising N-(3-amino-3-oxopropyl) dodecanamide.

10. A compound for treating a mixture of oil and water to thicken or gel the oil on the surface of the water, comprising a compound of Formula IIIA: ##STR00035## where R.sub.1 is selected from the group consisting of saturated and unsaturated C.sub.5 to C.sub.21 linear hydrocarbon chains, and wherein R.sub.1 comprises (i) an even number of carbons, (ii) an odd number of carbons, or (iii) one of: ##STR00036##

11. A composition for treating a mixture of oil and water to thicken or gel the oil on the surface of the water, comprising a compound that is one of: ##STR00037## ##STR00038## ##STR00039##

12. A composition comprising a mixture of two or more compounds as defined in claim 11.

13. A method of treating an oil-water mixture to gel or increase the viscosity of the oil, the method comprising the steps of: (a) preparing a solution or suspension comprising (i) one or more compounds in accordance with Formula II: ##STR00040## where: R.sub.1 is selected from the group consisting of: ##STR00041## R.sub.2 is selected from the group consisting of saturated and unsaturated C.sub.5 to C.sub.21 linear hydrocarbon chains, and ##STR00042## and G is selected from the group consisting of —H, —CH.sub.3, —NH.sub.2, —OH, —OCH.sub.3, and —(CH.sub.2).sub.2OH and (ii) a carrier solution comprising a water-miscible organic solvent and water, in which the organic solvent comprises in the range 0 to 50% by volume of said carrier solution; and (b) contacting the oil with the solution or suspension prepared in step (a).

14. A method of treating an oil-water mixture to gel or increase the viscosity of the oil, the method comprising the steps of: (a) preparing a suspension comprising one or more compounds in accordance with Formula III ##STR00043## where: R.sub.1 is selected from the group consisting of saturated and unsaturated C.sub.5 to C.sub.21 linear hydrocarbon chains; G is selected from the group consisting of —OH, —NH.sub.2, —NHNH.sub.2, —NOH, —NOCH.sub.3, and —N(CH.sub.2).sub.2OH; and n is 2, 3, 4 or 5, wherein the suspension is prepared by (i) adding the compounds or compositions to water, (ii) applying heat to dissolve the solids, and (iii) cooling the solution to precipitate the solids; and (b) contacting the oil with the suspension.

15. A method according to claim 14, wherein the oil comprises one of dilbit, diesel and conventional crude oil.

16. A method according to claim 15, wherein the amount of the compound used is in the range of 0.63 to 2.5% w/v.

17. A method according to claim 14 wherein the water comprises sea water.

18. A method of treating an oil-water mixture comprising the steps of: (a) suspending a supramolecular gellant in water to form a suspension; (b) heating the suspension until the gellant is dissolved; (c) cooling the suspension to form a hydrophobic structure or structures with a high surface area and high void volume; and (d) contacting the hydrophobic structure or structures with an oil-water mixture and thereby gelling the oil.

19. A method according to claim 18, wherein the gellant is selected from the group consisting of N-(3-amino-3-oxopropyl) dodecanamide, (S)—N-(1-hydrazineyl-1-oxopropan-2-yl)dodecanamide, 3-(Oleoylamino)propionamide and 1-[(S)-2-Amino-3-methylbutyrylamino]-1-dodecanone.

20. A method of treating a mixture of oil and water to herd the oil on the surface of the water comprising the steps of: (a) preparing a solution comprising one or more compounds and a carrier, (b) contacting the oil with the solution, wherein the one or more compounds are one of the Formula I: ##STR00044## where: R.sub.1 is selected from the group consisting of: ##STR00045## R.sub.2 is selected from the group consisting of saturated and unsaturated C.sub.5 to C.sub.21 linear hydrocarbon chains; and G is a cation.

21. The method according to claim 20, wherein the cation is selected from the group consisting of Na, K, Li, piperidinium, piperazinium, imidazolium, N-methyl imidazolium, and benzimidazolium.

22. A method of treating a mixture of oil and water to herd the oil on the surface of the water comprising the steps of: (a) preparing a solution comprising one or more compounds and a carrier, and (b) contacting the oil with the solution, wherein the one or more compounds are one of the Formula IC: ##STR00046## where: R.sub.2 is selected from the group consisting of saturated and unsaturated C.sub.5 to C.sub.21 linear hydrocarbon chains; and n is 1, 2, 3, 4 or 5.

23. A method of treating a mixture of oil and water to thicken or gel the oil on the surface of the water comprising the steps of: (a) preparing a solution comprising one or more compounds and a carrier, and (b) contacting the oil with the solution, wherein the one or more compounds are one of the Formula II: ##STR00047## where: R.sub.1 is selected from the group consisting of: ##STR00048## R.sub.2 is selected from the group consisting of saturated and unsaturated C.sub.5 to C.sub.21 linear hydrocarbon chains, and ##STR00049## and G is selected from the group consisting of —H, —CH.sub.3, —NH.sub.2, —OH, —OCH.sub.3, and —(CH.sub.2).sub.2OH.

24. A method according to claim 23, wherein G is —H.

25. A method of treating a mixture of oil and water to thicken or gel the oil on the surface of the water comprising the steps of: (a) preparing a solution comprising one or more compounds and a carrier, and (b) contacting the oil with the solution, wherein the one or more compounds are one of the Formula III: ##STR00050## where: R.sub.1 is selected from the group consisting of saturated and unsaturated C.sub.5 to C.sub.21 linear hydrocarbon chains; G is selected from the group consisting of —OH, —NH.sub.2, —NHNH.sub.2, —NOH, —NOCH.sub.3, and —N(CH.sub.2).sub.2OH; and n is 2, 3, 4 or 5.

26. A method of treating a mixture of oil and water to thicken or gel the oil on the surface of the water comprising the steps of: (a) preparing a solution comprising one or more compounds and a carrier, and (b) contacting the oil with the solution, wherein the one or more compounds are one of the Formula IIIA: ##STR00051## where R.sub.1 is selected from the group consisting of saturated and unsaturated C.sub.5 to C.sub.21 linear hydrocarbon chains.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a photograph showing oil added to a pan without oil-herder.

(2) FIG. 2 is a photograph showing oil added to a pan of water pre-dosed with N-fatty acid amino acid salt.

(3) FIG. 3 is a photograph showing the effect of gelling on dilbit-water mixtures.

(4) FIG. 4 is a photograph showing gel formation evaluation with dodecanoyl-L-alanine via solvent delivery at 2.5, 1.25, 0.83 and 0.63% w/v (Example 8).

(5) FIG. 5 is a photograph showing gel formation evaluation with dodecanoyl-β-alaninamide via solvent delivery at 2.5, 1.25, 0.83 and 0.63% w/v (Example 8).

(6) FIG. 6 is a photograph showing oil thickening evaluation with dodecanoyl-L-alanine via suspended solids delivery at 2.5, 1.25, 0.83 and 0.63% w/v. (Example 9)

(7) FIG. 7 is a photograph showing oil thickening evaluation with dodecanoyl-β-alaninamide via suspended solids delivery at 2.5, 1.25, 0.83 and 0.63% w/v. (Example 9)

(8) FIG. 8 is a series of photographs showing gelling of dyed diesel without the use of an organic solvent at 2 wt. % (Example 11).

(9) FIG. 9 is a series of photographs showing herding of dilbit (i.e., slick retraction) using an aqueous solution of L-phenylalanine, N-(1-oxotetradecyl)-, sodium salt. (Example 7)

(10) FIG. 10 is the plot of % degradation for determination of the biodegradability of the herder L-phenylalanine, N-(1-oxotetradecyl)-, sodium salt. (Example 13)

(11) FIG. 11 is the plot of % degradation for determination of the biodegradability of the gellant oleic-β-alaninamide. (Example 13)

SUMMARY OF THE INVENTION

(12) According to one embodiment of the invention, there is provided a composition for treating a mixture of oil and water to herd the oil, comprising a compound of Formula I:

(13) ##STR00004##
where: R.sub.1 is selected from the group consisting of:

(14) ##STR00005## R.sub.2 is selected from the group consisting of saturated and unsaturated C.sub.5 to C.sub.21 linear hydrocarbon chains; and G is a cation, for example, Na, K, Li, piperidinium, piperazinium, imidazolium, N-methyl imidazolium, and benzimidazolium.

(15) According to another aspect of the invention, there is provided a composition for treating a mixture of oil and water to herd the oil, comprising a compound of Formula IA:

(16) ##STR00006##
where: R.sub.2 is selected from the group consisting of saturated and unsaturated C.sub.5 to C.sub.21 linear hydrocarbon chains; G is a cation, for example, Na, K, Li, piperidinium, piperazinium, imidazolium, N-methyl imidazolium, and benzimidazolium; and n=1, 2, 3, 4 or 5.

(17) According to another aspect of the invention, there is provided a composition for treating a mixture of oil and water to herd the oil, comprising a water-miscible organic solvent and one or more compounds of Formula IB:

(18) ##STR00007##
where: R.sub.1 is selected from the group consisting of:

(19) ##STR00008##  and R.sub.2 is selected from the group consisting of saturated and unsaturated C.sub.5 to C.sub.21 linear hydrocarbon chains.

(20) According to another aspect of the invention, there is provided a composition for treating a mixture of oil and water to herd the oil, comprising a water-miscible solvent and one or more compounds of Formula IC:

(21) ##STR00009##
where: R.sub.2 is selected from the group consisting of saturated and unsaturated C.sub.5 to C.sub.21 linear hydrocarbon chains; and n=1, 2, 3, 4 or 5.

(22) According to another aspect of the invention, there is provided a composition for treating a mixture of oil and water to gel or increase the viscosity of the oil, comprising a compound of Formula II:

(23) ##STR00010##
where: R.sub.1 is selected from the group consisting of:

(24) ##STR00011## R.sub.2 is selected from the group consisting of saturated and unsaturated C.sub.5 to C.sub.21 linear hydrocarbon chains, and

(25) ##STR00012##  and G is selected from the group consisting of —H, —CH.sub.3, —NH.sub.2, —OH, —OCH.sub.3, and —(CH.sub.2).sub.2OH.

(26) According to a further aspect of the invention, there is provided a composition for treating a mixture of oil and water to thicken or gel the oil, comprising a compound of Formula III:

(27) ##STR00013##
where: R.sub.1 is selected from the group consisting of saturated and unsaturated C.sub.5 to C.sub.21 linear hydrocarbon chains; G is selected from the group consisting of —OH, —NH.sub.2, —NHNH.sub.2, —NOH, NOCH.sub.3, and —N(CH.sub.2).sub.2OH; and n=2, 3, 4 or 5.

(28) According to a further aspect of the invention, there is provided a compound of Formula IIIA:

(29) ##STR00014## where R.sub.1 is selected from the group consisting of saturated and unsaturated C.sub.5 to C.sub.21 linear hydrocarbon chains.

(30) According to a further aspect of the invention, there is provided a method of treating an oil-water mixture to herd the oil and thereby increase the thickness of the oil layer, the method comprising contacting the oil-water mixture with a composition as aforesaid.

(31) According to a further aspect of the invention, there is provided a method of preventing or minimizing the spread of oil on water and thereby maintaining the thickness of the oil phase, the method comprising pre-treating the water before it is contacted with the oil with a composition as aforesaid.

(32) According to a further aspect of the invention, there is provided a method of reducing the adhesion of oil to solid substrates, the method comprising conditioning the solids with a composition as aforesaid before the solids are contacted with the oil.

(33) According to a further aspect of the invention, there is provided a method of treating an oil-water mixture to gel or increase the viscosity of the oil, comprising suspending one or more compositions or compounds as aforesaid in water to form an aqueous suspension, and adding the aqueous suspension to oil-water mixture.

(34) According to a further aspect of the invention, there is provided a method of treating an oil-water mixture to gel or increase the viscosity of the oil, the method comprising the steps of: (a) preparing a solution or suspension comprising (i) one or more compounds in accordance with Formula II, III or IIIA or compositions as aforesaid and (ii) a carrier solution comprising a water-miscible organic solvent and water, in which the organic solvent comprises in the range 0 to 50% by volume of said carrier solution; and (b) contacting the oil with the solution or suspension prepared in step (a).

(35) According to a further aspect of the invention, there is provided a method of treating an oil and water mixture to gel or increase the viscosity of the oil, the method comprising the steps of: (a) preparing a solution comprising (i) one or more compounds in accordance with Formula II, III or IIIA or compositions as aforesaid and (ii) a water-miscible organic solvent; (b) adding water to the solution prepared in step (a) to precipitate the compound and produce a suspension comprising the precipitated compound, the organic solvent and water, in which the proportion of the organic solvent in the carrier solution is 50% by volume or less; and (c) contacting the oil with the suspension.

(36) According to a further aspect of the invention, there is provided a method of treating an oil-water mixture to gel or increase the viscosity of the oil, the method comprising the steps of: (a) preparing a solution or suspension comprising (i) one or more compounds in accordance with Formula II, III or IIIA or compositions as aforesaid and (ii) a carrier solution comprising a water-miscible organic solvent and water, in which the organic solvent comprises in the range 0 to 50% by volume of said solution, the compound being present in the solution or suspension in the solid state; (b) removing the wetted solids from the suspension; and (c) contacting the oil with the wetted solids.

(37) According to a further aspect of the invention, there is provided a method of treating an oil-water mixture to gel or increase the viscosity of the oil, the method comprising the steps of: (a) preparing a suspension comprising one or more compounds in accordance with Formula II, III or IIIA or composition as aforesaid, wherein the suspension is prepared by (i) adding the compounds or compositions to water, (ii) applying heat to dissolve the solids, and (iii) cooling the solution to precipitate the solids; and (b) contacting the oil with the suspension.

(38) According to a further aspect of the invention, there is provided a method of treating an oil-water mixture comprising the steps of: (a) suspending a supramolecular gellant in water to form a suspension; (b) heating the suspension until the gellant is dissolved; (c) cooling the suspension to form a hydrophobic structure or structures with a high surface area and high void volume; and (d) contacting the hydrophobic structure or structures with an oil-water mixture and thereby gelling the oil.

(39) According to a further aspect of the invention, there is provided a method of treating an oil-water mixture to gel the oil, comprising a composition or a compound according to a preceding aspect of the invention formed as a hydrophobic structure or structures with a high surface area and high void fraction, and adding this “active” suspension to a mixture of the oil in water. These “active” materials will gel hydrophobic liquids such as oils due to the combination of hydrophobicity, high surface area and high void fraction. “Inactive” materials are chemically identical (i.e., no differences in chemical structure), are similarly hydrophobic but lack the high surface area and high void fraction.

(40) According to a further aspect of the invention, there is provided a method of treating an oil-water mixture to gel the oil, the method comprising the steps of: (a) preparing a solution or suspension comprising (i) one or more compounds in accordance with Formula II, III or IIIA as disclosed herein and (ii) a mixture of a water-miscible organic solvent and water, in which the organic solvent comprises in the range of 0 to 50% by volume of said solution; and (b) contacting the oil with the solution or suspension prepared in step (a).

(41) According to a further aspect of the invention, there is provided a method of treating an oil in water to gel the oil, the method comprising the steps of: (a) preparing an active suspension comprising one or more compounds in accordance with Formula II, III or IIIA as disclosed herein where the compound has been heated in water until dissolved and the solution is then cooled to precipitate the compound to form the active suspension; and (b) contacting the oil with the active suspension prepared in step (a).

(42) Benefits and advantages of embodiments of the present invention include, but are not limited to, providing compositions and methods for reducing the area of an oil slick and therefore increasing the thickness of the slick, and compositions and methods to gel or increase the viscosity of the oil. Further benefits of the compositions and compounds disclosed as oil spill herders is that they can be prepared from biobased feedstocks and are biodegradable. Further benefits of the compositions and compounds disclosed as oil thickeners or gellants include preparation from biobased feedstocks, low toxicity, low dosing requirements (i.e., high capacity for oil) and the reduction or elimination of the need to use an organic solvent to apply the thickener or gellant to an oil-water mixture in order to gel the oil phase.

(43) Further aspects of the invention and features of specific embodiments of the invention are described below.

DETAILED DESCRIPTION

(44) This invention provides chemical-based methods and products for treating mixtures of water and hydrophobic liquids with a particular utility in the field of oil spill response. Specifically, the invention provides methods and chemical agents for mitigating the impact of a spill and facilitating oil recovery. The agents act via a range of mechanisms which include herding, reducing adhesiveness, thickening (increased viscosity) and gelling.

(45) Herders

(46) N-fatty acid amino acid (FA-AA) conjugates display oil-herding behavior when formulated as the free acid in water-miscible organic solvents. Appropriate organic solvents include methanol, ethanol and isopropanol. When dissolved in an appropriate solvent and sprayed around the periphery of a layer of oil on water, these oil-herders act to modify the surface tensions of the water and oil and the water-oil interfacial tension and cause the layer of oil to contract. The surface area of the oil layer is reduced and as a result the thickness of the oil layer is increased.

(47) The need for a water-miscible organic solvent can be eliminated if the FA-AA conjugate is formulated as a salt. Various salts of FA-AA conjugates are water soluble and demonstrate the ability to herd oils and increase the thickness of the oil layer. When the FA-AA conjugates in a water-miscible organic solvent or the corresponding salts in water are pre-dosed into water, application of an oil results in contraction of the oil slick where the area of the oil slick is reduced and the thickness of the oil layer is increased. The oil does not spread over the surface. The oil volume and the area of the resulting pooled oil can be used to calculate the thickness of the layer. FIGS. 1 and 2 illustrate the result of oil added to a pan of water without oil-herder, and to a pan of water pre-dosed with an FA-AA salt (sodium tetradecanoylalaninate), respectively. Such a pre-treatment could potentially also be used to protect an environmentally-sensitive area against a spreading oil slick.

(48) When an oil (e.g., dilbit) is applied to water in a pan, the oil spreads to cover the surface of the water. Application of FA-AA as a salt (e.g., Li, Na or K salts) dissolved in water results in contraction of the oil layer. The pooled oil has reduced surface area and greater slick thickness. This is illustrated in FIG. 9A-E where a solution of the salt of a FA-AA is applied to an aliquot of oil which has been allowed to spread in a pan (FIG. 9A). Application of the aqueous herder solution results in contraction of the slick over time. Images taken at 1, 5, 10 and 20 minutes are shown in FIGS. 9B, 9C, 9D and 9E respectively.

(49) Solid substrates (e.g., sand, glass beads) can be pretreated with herder to reduce the adhesion of oil. This can be demonstrated by conditioning the solid substrate (e.g., sand, glass beads) by contacting it with a solution of herder (for example, 0.086 to 10 g/L) for a brief period of time. If oil is then brought into contact with the treated solid substrate for a period of time, the amount of oil that adheres to the substrate can be reduced by 40-50%, depending upon the concentration of herder during the conditioning step.

(50) Formulas I and IA are general formulas of FA-AA compounds which may be formulated as salts in water and have oil-herding properties. The aqueous solutions of these salts can also reduce the amount of oil which adheres to substrates if the substrates are conditioned with the herder solutions before contact with the oil. The stereochemistry is not specified in the instance of the α-amino acids since either enantiomer and racemic mixtures have oil-herding and adhesion reduction properties.

(51) ##STR00015##
where: R.sub.1 is selected from the group consisting of:

(52) ##STR00016## R.sub.2 is selected from the group consisting of saturated and unsaturated C.sub.5 to C.sub.21 linear hydrocarbon chains; and G is a cation such as Na, K, Li, piperidinium, piperazinium, imidazolium, N-methyl imidazolium, and benzimidazolium.

(53) ##STR00017##
where: R.sub.2 is selected from the group consisting of saturated and unsaturated C.sub.5 to C.sub.21 linear hydrocarbon chains; and G is selected from the group consisting of Na, K, Li, piperidine, piperazine, imidazole, N-methyl imidazole, and benzimidazole; and n=1, 2, 3, 4 or 5.

(54) According to one embodiment, the compound of Formula I comprises L-Alanine, N-(1-oxododecyl)-, sodium salt or its enantiomer or the racemic mixture.

(55) According to another embodiment, the compound of Formula I comprises L-Phenylalanine, N-(1-oxododecyl)-, sodium salt or its enantiomer or the racemic mixture.

(56) According to another embodiment, the compound of Formula I comprises L-Phenylalanine, N-(1-oxotetradecyl)-, sodium salt or its enantiomer or the racemic mixture.

(57) According to another embodiment, the compound of Formula I comprises L-tyrosine, N-(1-oxohexadecyl)-, sodium salt or its enantiomer or the racemic mixture.

(58) Formulas IB and IC are general formulas of the free acids corresponding to the salts of Formulas I and IA. The free acids of Formulas IB and IC may be formulated in water-miscible organic solvents (delivery solvents) to produce solutions which have oil-herding properties. Formulas IB and IC are respectively:

(59) ##STR00018##
where: R.sub.1 is selected from the group consisting of:

(60) ##STR00019##  and R.sub.2 is selected from the group consisting of saturated and unsaturated C.sub.5 to C.sub.21 linear hydrocarbon chains.

(61) According to some embodiments of the invention, the compound of Formula IB comprises stearoyl alanine, lauroyl alanine or myristyl phenylalanine.

(62) ##STR00020##
where: R.sub.2 is selected from the group consisting of saturated and unsaturated C.sub.5 to C.sub.21 linear hydrocarbon chains; and n=1, 2, 3, 4 or 5.

(63) The compounds of Formulas I, IA, IB and IC, having oil-herding properties, may be used in methods of treating oil-water mixtures. In one embodiment, a method of treating an oil on water mixture to herd the oil and thereby increase the thickness (i.e. depth) of the oil layer comprises contacting the oil-water mixture with a composition having one of the compounds. In another embodiment, a method of preventing or minimizing the spread of an oil on water and thereby maintaining the thickness of the oil phase, comprises applying the herder to the water before it is contacted with the oil. In another embodiment, a method of reducing the adhesion of oil to solid substrates comprises conditioning the solids with a composition having one of the compounds before the solids are contacted with the oil. The conditioning comprises bringing the composition into contact with the solids for a suitable period of time, for example one hour.

(64) Gellants

(65) Replacement of the acid (COOH) group of fatty acid α-amino acid conjugates with other groups capable of acting as hydrogen bond (H-bond) donors and acceptors results in potent phase selective organo gellants. When added to an oil-water mixture, these compounds can increase the viscosity of the oil phase or form a gel. Amides and their derivatives have been demonstrated to provide varying degrees of oil thickening (i.e. viscosity enhancing) and gelling behavior. Among the functional groups which can replace the carboxylic acid group are: primary and secondary amides, hydrazines and hydroxamic acids.

(66) Within the amides and their derivatives of N-fatty acid α-amino acid conjugates, the length of the fatty acid can be varied from C6 to C20 to still provide phase selective organo gellants. Unsaturated bonds within the fatty acid are also tolerated (i.e., alkene and alkynes). The fatty acid component of the N-fatty acid α-amino acid conjugates need not be pure (i.e., a single discrete chemical species). Mixtures of fatty acids can result in a mixture of N-fatty acid α-amino acid conjugates which retain PSOG behavior. Potential sources of fatty acid mixtures include plant and animal oils such as coconut and canola oils and beef tallow.

(67) Formula II is a general formula of amides and their derivatives of N-Fatty acid α-amino acid-based compounds with phase selective gelling activity:

(68) ##STR00021##
where: R.sub.1 is selected from the group consisting of:

(69) ##STR00022## R.sub.2 is selected from the group consisting of saturated and unsaturated C.sub.5 to C.sub.21 linear hydrocarbon chains, and

(70) ##STR00023## and G is selected from the group consisting of —H, —CH.sub.3, —NH.sub.2, —OH, —OCH.sub.3, and —(CH.sub.2).sub.2OH.

(71) In some embodiments, the compound of Formula II comprises a compound wherein G is —H. In some embodiments, the compound of Formula II is one of:

(72) ##STR00024##

(73) In one embodiment, the compound of Formula II comprises L-Alanine, N-(1-oxododecyl)-, hydrazide.

(74) In addition to chirally pure α-amino acids (using D/L or R/S designation), we have determined that, surprisingly, racemic mixtures could also be employed to prepare PSOGs. The potential to use racemic mixtures as a feedstock provides economic incentives due to the higher costs normally associated with chirally pure materials.

(75) As in the case of parent acid compounds, the analogs presented in Formula II can be administered via different routes. The use of a water-soluble delivery solvent (co-solvent method) to introduce the compounds into a mixture of oil and water is useful for screening for gelling activity. Alternatively, the compound can be delivered as a solid to the oil-water mixture which is then heated to dissolve the compound. Agitation followed by a cooling step results in gel formation. The preferred option is to heat the gellant in a mixture of water and a water-miscible organic solvent until the solid is dissolved. The resulting solution is then cooled to precipitate the gellant. The proportion of organic solvent can vary from 0 to 50% by volume. The most preferred additional option is to heat the PSOG compound in water until it is dissolved. Upon cooling, the PSOG compounds precipitates from solution to form an active suspension of fibrous solids in water. Addition of this suspension to an oil water mixture (or vice versa) followed by agitation results in the formation of a gel.

(76) In some instances, some of the N-fatty acid α-amino acid analogs presented in Formula III, shown below, present as powdery white solids. For some of these compounds an additional option for compound delivery was possible. The compounds could be suspended as a powder in water and the aqueous suspension then added to a mixture of water and oil. Upon agitation, the result was a noticeable thickening of the oil phase and an increase in volume due to the formation of a stable water in oil emulsion. This is illustrated in FIG. 3, showing vials of dilbit (diluted bitumen) and water which, from left to right are a control (untreated), oil treated to a thickened state with a PSOG suspended in water, and oil treated with a PSOG delivered as solution in a water-miscible-solvent to produce a gel pellet. The PSOG used was oleic alaninamide. The ability to deliver phase selective gellants using water as a delivery medium to thicken a hydrophobic phase towards a gel state has not been reported in the literature.

(77) N-fatty acid amino acids and their derivatives which incorporate higher order amino acids such as β and γ analogs also provide potent gellants. These analogs have additional methylene groups in the amino acid group resulting in slightly elongated analogs. Formula III is a general formula of phase selective organo gellants incorporating longer amino acids:

(78) ##STR00025##
where: R.sub.1 is selected from the group consisting of saturated and unsaturated C.sub.5 to C.sub.21 linear hydrocarbon chains; G is selected from the group consisting of —OH, —NH.sub.2, —NHNH.sub.2, —NOH, NOCH.sub.3, and —N(CH.sub.2).sub.2OH; and n=2, 3, 4 or 5.

(79) According to one embodiment, the compound of Formula III comprises N-(3-amino-3-oxopropyl) dodecanamide.

(80) Preferred compounds in accordance with Formula III have the general structure of Formula IIIA:

(81) ##STR00026## where R.sub.1 is selected from the group consisting of saturated and unsaturated C.sub.5 to C.sub.21 linear hydrocarbon chains.

(82) In some embodiments of Formula IIIA, R.sub.1 comprises an even number of carbons, or alternatively, an odd number of carbons.

(83) In some embodiments of Formula IIIA, R.sub.1 comprises one of:

(84) ##STR00027##

(85) The use of β-alanine and longer unsubstituted amino acids and their derivatives removes the stereocenter, which can lower the cost of starting materials.

(86) In some embodiments, the compound of Formula II, III or IIIA comprises one of:

(87) ##STR00028## ##STR00029## ##STR00030##

(88) In some embodiments of the invention, one or more compounds in accordance with those disclosed herein, e.g., in accordance with Formulas II, III and IIIA, are part of a composition which has oil-thickening, oil-gelling and/or emulsifying action. The oil thickening, oil gelling and/or emulsification action can be promoted by delivering the compound in a composition with a water-soluble additive that acts as a solubility aid.

(89) Examples of such additives include NaCl, NaBr, urea, glucose, sodium phosphate, polysorbate 20, polysorbate 80, trehalose, sodium tartrate, and citric acid, and mixtures thereof.

(90) As in the case of the α-amino acids and their derivatives, a mixture of fatty acids, such as those derived from plant and animal oils, can be used to make mixtures of compounds with the higher order amino acids and their amide derivatives which retain the ability to selectively gel hydrophobic liquids in the presence of water. Compounds with longer fatty acid groups can also be formulated and delivered as a suspension of a solid in water. Alternatively, the compounds can also be delivered as an active suspension in water. The active suspension in water is formed by heating the solids in water followed by a cooling step to precipitate the compound as fibrous solids.

(91) The oil-water mixture treatment compounds disclosed herein have been determined to be effective at gelling oil, for example in an oil spill situation, when delivered in a carrier that comprises either exclusively water or a low proportion of a water-miscible organic solvent in water. The use of such compositions, by eliminating or reducing the level of organic solvent relative to that suggested in prior art, has the benefit of lessening flammability, thus making the process safer, being less toxic for spill cleanup workers, and having a lower environmental impact. The composition may comprise 0 to 50% by volume organic solvent in the total water-solvent mixture. Suitable organic solvents include ethanol, isopropyl alcohol, 1-butanol, acetonitrile, N,N-dimethylformamide, 1,3-butanediol and 1-propanol.

(92) In one embodiment using a low proportion of organic solvent, the compound is delivered as a solution or suspension in water after being prepared using an organic co-solvent in proportions of 50% by volume or less of solvent to water. The compound, which is a solid, is first treated with a solution comprising a minimal amount of water-miscible organic solvent in water. The compound may either dissolve or suspend in the water-miscible organic solvent, producing a solution or suspension. Heat may be used to dissolve the solid in the solution. The cooled solution or suspension is then added to an oil-water mixture to effect gelation of the oil phase.

(93) In an alternative embodiment using a low proportion of organic solvent, water is added to a mixture of the compound in an organic solvent to precipitate the compound and bring the proportion of organic solvent to 50% by volume or less in the carrier solution. The resulting suspension, which is composed predominantly of water, is then added to an oil-water mixture to effect gelation of the oil phase.

(94) In a further alternative embodiment using a low proportion of organic solvent, the compound is removed from a water-organic solvent mixture. The solvent mixture may comprise 0 to 50% by volume organic solvent in the total water-solvent mixture. The compound is present in the solvent as wetted solids. The removal of the wetted solids may be done by a variety of mechanical means, including the use of a filter or by centrifugation of the mixture. The removed wetted solids are then added to an oil-water mixture to effect gelation of the oil phase.

(95) In a further alternative embodiment using only water, the compound is heated and dissolved in water. The solution is allowed to cool to precipitate the compound as low density solids. Addition of this active suspension to a mixture of oil and water followed by gentle mixing results in absorption of the oil and gel formation.

(96) In a further embodiment, a supramolecular gellant that is an amphiphile capable of self-assembly is added to water and heated until dissolved. Upon cooling, the compound reforms as solids via a self-assembly. The re-formed solids have higher surface area and higher void fraction than pre-dissolved material due to the self-assembly process, which may produce structures which include, but are not limited to, sheets, fibers, ribbons and spherulites. The re-formed solids are hydrophobic/oleophilic. The void spaces are originally occupied by water. Upon contact with an oil phase, the water is displaced by the oil. The volume of the gellant is reduced as the oil is absorbed. The final volume of the gelled oil is approximately equal to the original volume of the oil. Examples of gellants capable of forming structures via self-assembly which can gel oils include N-(3-amino-3-oxopropyl) dodecanamide, (S)—N-(1-hydrazineyl-1-oxopropan-2-yl) dodecanamide, 3-(Oleoylamino)propionamide and 1-[(S)-2-Amino-3-methylbutyrylamino]-1-dodecanone.

(97) The compounds disclosed herein offer distinct advantages over what has been reported in the patent and academic literature. The herders disclosed herein represent improvement over currently-available options in many ways which include: (a) elimination of the use of synthetic polymer based chemistries; (b) reduction or elimination of the use of organic carrier solvents in favour of aqueous-based delivery; (c) the use of bio-based feedstocks and, (d) herding agents which are biodegradable.

(98) The thickeners (viscosity enhancers) and gellants disclosed herein represent an advance in the field for a variety of reasons which include one or more of: (a) the elimination of the need to use heat to dissolve the gellant in a hydrophobic phase-water mixture to effect gelation; (b) the elimination of the need to use high proportions of a water-miscible organic delivery solvent; (c) improvement in loading requirements from 10-20% w/v to less than 2.5% w/v; (d) the elimination of the need to use an organic wetting solvent; (e) improved gelling times to less than 20 minutes; (e) the use of bio-based feedstocks to produce agents which are of lower environmental toxicity; and (f) the reduction of costs for potential feedstock by the elimination of starting materials that contain a chiral center; (g) the ability to use heat to dissolve and re-suspend the gellant in an all water solvent system which eliminates the need to use an organic solvent; and (h) biodegradability.

EXAMPLES

Example 1

Synthesis of N-(3-amino-3-oxopropyl)dodecanamide

(99) B-alaninamide (3 g, 24.1 mmol) was added to chloroform (80 mL). This mixture was cooled in an ice bath. Triethylamine (5.36 g, 53 mmol) was added via syringe. The mixture was stirred for two minutes after which lauroyl chloride (5.80 g, 26.5 mmol) was added dropwise via syringe. The reaction was allowed to warm to room temperature and stirred overnight. The product was isolated by suction filtration as a white powdery solid (5.86 g, 90%).

Example 2

Synthesis of L-Alanine, N-(1-oxododecyl)-, hydrazide

(100) L-alanine methyl ester hydrochloride (4 g, 28.6 mmol) was dissolved in chloroform (60 mL). Triethylamine (6.38 g, 63 mmol) was added via syringe. The mixture was cooled in an ice. Lauroyl chloride (6.9 g, 31.5 mmol) was added dropwise via syringe. The ice bath was removed and the reaction was stirred at room temperature overnight. The crude reaction was diluted with chloroform (300 mL). The organic phase was washed with 0.2 M HCl (1.5 L), 5% NaHCO.sub.3 (800 mL) and saturated brine (300 mL). The organic phase was dried over sodium sulphate and filtered. The solvent was removed under reduced pressure to yield the methyl ester as a white solid in quantitative yield.

(101) The methyl ester (1.5 g, 5.1 mmol) was dissolved in methanol (40 mL). Hydrazine monohydrate (7.70 g, 154 mmol) was added dropwise. The reaction was stirred overnight at room temperature. Additional methanol (50 mL) was added to the reaction which was stirred for an additional four hours. The methanol was removed under reduced pressure. The crude was taken up in chloroform (400 mL). The organic phase was washed with brine (75 mL). The chloroform was separated and the remaining water and rag layer were washed with ethyl acetate (400 mL). The combined organic phases were dried over sodium sulphate and the solvent removed under reduced pressure to yield the product as a white solid in quantitative yield.

Example 3

Preparation of L-Alanine, N-(1-oxododecyl)-, sodium salt

(102) L-Alanine, N-(1-oxododecyl)- (1 g, 3.7 mmol) was suspended in water (50 mL). Sodium hydroxide (0.15 g, 3.7 mmol) was added as a solid. The mixture was agitated. Additional water was added if necessary to solubilize the salt. The solution was used as is.

Example 4

Gelling or Thickening Method for PSOGs—Co-Solvent Method

(103) PSOGs were screened against dilbit, diesel and sunflower. The dilbit used in the Examples herein was prepared by dissolving bitumen in naphtha in a 65:35 ratio of bitumen to naphtha. A typical screening method utilized a 1:4 ratio of hydrophobic liquid to water (i.e., 1 mL oil product to 4 mL water) in a 20 mL vial. The gellant (22.5 mg) was dissolved in a carrier solvent, which was typically methanol, ethanol or isopropanol. Heat was applied to dissolve the solid if necessary. The gellant solution was transferred to the oil-water mixture and the vial was capped. Agitation was applied and the mixture allowed to settle. Gel formation typically presented as the formation of an oil pellet or a thickening of the oil phase.

Example 5

Gelling or Thickening Method for PSOGs—Dry Solid Delivery with Heating

(104) Using a mixture of 1 mL of oil to 4 mL water in a 20 mL vial, 22.5 mg of gellant (oleic-β-alanine amide) was added as a solid and the vial capped. Heat was applied until the solid dissolved. The oil-water mixture was allowed to cool to room temperature undisturbed. Gel formation typically presented as a gel cap over the water layer or as a thickened (higher viscosity) oil.

Example 6

Gelling or Thickening Method for PSOGs—Delivery as an Aqueous Suspension

(105) Gellants which presented as fine powdery solids were suspended in water (4-5 mL). The suspension was sonicated to reduce the particle size if necessary. The suspension was added to a mixture of 1 mL oil to 4 mL water in a 20 mL vial. The vial was capped and the mixture agitated. Thickening of the oil, likely due to the formation of an emulsion, could be observed within 15 minutes.

Example 7

Measurement of Herding Capacity as Measured by Slick Thickness

(106) The herder formulation was pre-dosed into 1 L of water in a flat glass pan under which was a 1×1 cm grid. A known volume of oil was applied to the pre-dosed water. A digital photo of the oil slick was recorded. The image was processed using ImageJ in order to calculate the area of the slick. Since volume and area are known, it is possible to calculate the thickness of the slick as a function of herder dosing. Compounds that maximize the thickness of the slick are considered better oil-herders.

(107) Alternatively, an oil was applied to water in a pan and allowed to spread. A herder (e.g. L-phenylalanine, N-(1-oxotetradecyl)-, sodium salt) was applied to the water to retract the slick (i.e. decrease surface area while increasing the thickness/depth of the oil layer). Overhead photography was used to capture the herding process. The images were processed to determine the area of the slick and allow for calculation of the slick thickness (FIG. 9).

Example 8

Evaluation of Gelling Ability—Solution Phase Delivery

(108) Four portions of the prior art compound dodecanoyl-L-alanine of differing masses were weighed out and each dissolved in 1 mL of isopropyl alcohol. These four solutions were added to four separate 20 mL vials of 1:4 mL dilbit and water. The amounts of dodecanoyl-L-alanine used in the different portions resulted in dosing ratios of 2.5, 1.25, 0.83 and 0.63% w/v relative to dilbit. The vials were agitated and the results are shown in FIG. 4. Gel formation was evaluated qualitatively. It was found that the dodecanoyl-L-alanine only formed a gel at a dosing of 2.5% w/v.

(109) This procedure was repeated with dodecanoyl-β-alaninamide. Four portions of dodecanoyl-β-alaninamide of differing masses were weighed out and each dissolved in 1 mL of isopropyl alcohol. These four solutions were added to four separate 20 mL vials containing 1 mL dilbit and 4 mL water. The amounts of dodecanoyl-β-alanine used in the different portions resulted in dosing ratios of 2.5, 1.25, 0.83 and 0.63% w/v relative to dilbit. The vials were agitated and the results are shown in FIG. 5. Gel formation was evaluated qualitatively. It was found that the dodecanoyl-β-alaninamide formed a gel at all dosing ratios evaluated from 2.5 to 0.63% w/v.

Example 9

Aqueous Suspension Delivery of Gellants

(110) Four portions of prior art compound dodecanoyl-L-alanine of differing masses were weighed out and each suspended in 1 mL of water. These four suspensions were added to four separate 20 mL vials of 1:4 mL dilbit and water. The amounts of dodecanoyl-L-alanine used in the different portions resulted in dosing ratios of 2.5, 1.25, 0.83 and 0.63% w/v relative to dilbit. The vials were agitated and the results are shown in FIG. 6. Oil thickening was evaluated qualitatively. It was found that the dodecanoyl-L-alanine did not thicken the oil at any of the dosing levels tested when applied as a solid suspended in water.

(111) This experiment was repeated with dodecanoyl-β-alaninamide. Four portions of dodecanoyl-β-alaninamide of differing masses were weighed out and each suspended in 7 mL of water. These four suspensions were added to four separate 20 mL vials of 1:4 mL dilbit and water. The amounts of dodecanoyl-β-alaninamide used in the different portions resulted in dosing ratios of 2.5, 1.25, 0.83 and 0.63% w/v relative to dilbit. The vials were agitated and the results are shown in FIG. 7. Oil thickening was evaluated qualitatively. It was found that the dodecanoyl-3-alaninamide thickened the oil at all dosing levels which were evaluated from 2.5 to 0.63% w/v.

Example 10

Assessment of Herder Activity

(112) Stearoyl alanine was dissolved in isopropyl alcohol. An aliquot of this solution was added to 1 L of water in a pan. The final dosage of stearoyl alanine was 0.77 mg in 1 L of water. Dilbit (2.27 g) was added. An overhead digital photo was taken of the oil after 10 minutes. The photo was analyzed to determine the area of the oil which could be used to calculate the thickness of the oil layer. The oil slick was determined to be 2.9 mm thick.

(113) Silsurf, (trademark) a commercial herder added to 1 L of water in a glass pan for a final dosing of 1 mg. Dilbit (1.61 g) was added to the water. An overhead digital photo was taken of the oil after 10 minutes. The photo was analyzed to determine the area of the oil which could be used to calculate the thickness of the oil layer. The oil slick was determined to be 2.0 mm thick. The stearoyl alanine herder produced a thicker oil layer than Silsurf at a comparable dosage.

Example 11

Demonstration of Gelling Activity Using Mixed Organic Solvent-Water

(114) The gellant oleic-p-alaninamide (25 mg) was suspended in 5 mL of a mixed solvent system composed of 2:3 1,4-butanediol and water. The mixture was heated to dissolve the solids. Upon cooling, the gellant precipitates as a cotton-like mass. Addition of this suspension to a mixture 1:4 oil (i.e. dilbit, diesel, or crude oil) and seawater followed by gentle agitation resulted in gelling of the oil phase in less than 1 minute.

Example 12

Demonstration of Gelling Activity without the Need for an Organic Solvent

(115) The gellant oleic-β-alaninamide (25 mg) was suspended 5 mL of water which was dyed pink for visualization purposes. The mixture was heated to dissolve the gellant. Upon cooling, the gellant precipitated as a cotton-like mass which retains the water. Addition of dye free water demonstrated that there is very little to no leaching of the dyed water from the gellant mass (FIG. 8A). Upon the addition of diesel, which has been dyed blue, the hydrophobic phase entered the gellant mass upon contact and displaced the dyed water (FIGS. 8B and 8C) to produce the gelled diesel.

Example 13

Measuring Biodegradability of Select Herder and Gellant

(116) The herder L-phenylalanine, N-(1-oxotetradecyl)-, sodium salt and the gellant oleic-β-alaninamide were assessed for biodegradability in using OECD 301F guideline, manometric respirometer test. The herder reduced the theoretical oxygen demand by 68% in the 10-day window and is considered readily biodegradable. The gellant reduced the theoretical oxygen demand by 30% in the 10-day window and is classified as inherently biodegradable. The plot of data for % degradation for the herder and gellant is shown in FIGS. 10 and 11 respectively.

Example 14

Reduction of Oil Adhesion by Conditioning with Aqueous Herder Solution

(117) Glass bead were used as a model substrate. The beads were weighed and transferred into a pre-weighed 60 mL plastic syringe. The beads were immersed in an aqueous solution of herder, C14-L-Phe-COONa, for 1 hour. An oil layer of conventional crude oil was added to the surface of the herder solution above the glass beads. The oil was lowered hydrostatically to immerse the beads in oil for 1 hour after which the oil was raised hydrostatically above the level of the beads. The water above the oil and beads were both removed. The mass of the oil retained on the glass beads was calculated as the difference between the mass of the oil-coated beads and the initial mass of the beads. The results are shown in Table 1.

(118) TABLE-US-00001 TABLE 1 Effect of herder on oil adhesion on glass beads Average mass of conventional crude Herder concentration (g/L) retained (g) 10 1.8 2.9 1.6 0.57 1.3 0.086 1.9 Control (no herder) 3.2

(119) The ability of a herder solution to decrease the amount of oil adhesion on the model substrates is evident. The amount of oil adhering to the glass beads can be decreased by as much as 50% by pre-conditioning the beads with an aqueous solution of herder.