Branched amino acid surfactants

Abstract

To provide derivatives of amino acids that have branched alkyl structures and surface-active properties.SOLUTION: The amino acids may be naturally occurring or synthetic amino acids, or may be obtained via a ring-opening reaction of a lactam, such as caprolactam. The amino acids may be functionalized to form a compound that is surface-active and has advantageous surfactant characteristics. The compounds of the present disclosure have low critical micelle concentrations (CMCs) and superior ability to lower the surface tension of a liquid.SELECTED DRAWING: None

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Patent Application No. 63 / 049,726, filed July 9, 2020, the entire contents of which are incorporated herein by reference.

[0002] The present disclosure relates to derivatives of amino acids and methods for their synthesis, which contain branched alkyl structures and have surface active properties. [Background technology]

[0003] Surfactants (molecules with surface active properties) are an important class of molecules with highly sought-after characteristics. Surfactants can be nonionic, zwitterionic, cationic, or anionic. Often, these compounds are amphiphilic molecules with a water-insoluble hydrophobic "tail" group and a water-soluble hydrophilic "head" group. These compounds can adsorb at interfaces, such as the interface between two liquids, between gas and liquid, or between solid and liquid. In the case of the interface between water and oil, the hydrophilic head group extends into the water while the hydrophobic tail extends into the oil. When added to water, the hydrophilic head group extends into the water while the hydrophobic tail extends into the air. The presence of surfactant disrupts the intermolecular interactions between water molecules and replaces them with weaker interactions between the water molecules and the surfactant. This results in a lowering of the surface tension and can also act to stabilize the interface.

[0004] At high enough concentrations, surfactants may form aggregates that limit the exposure of the hydrophobic tails to the polar solvent. One such aggregate is a micelle, where the molecules are arranged in a spherical shape with the hydrophobic tails on the inside of the sphere and the hydrophilic heads on the outside to interact with the polar solvent. The effect that any compound has on surface tension and the concentration at which it forms micelles can be useful as a defining feature of a surfactant.

[0005] Surfactants are widely used in commercial applications in a variety of formulations, from detergents to hair care products and cosmetics. Compounds with surface active properties are used as soaps, detergents, lubricants, wetting agents, foaming agents, and spreading agents, among others. Thus, there is a continuing need to identify and synthesize such compounds.

[0006] However, it can be difficult to predict whether any compound will have surface active properties from its structure alone, let alone other important features such as interfacial adsorption kinetics, minimum achievable surface tension, and / or ability to wet hydrophobic and / or oleophobic surfaces, which are also essential for a compound to be a useful surfactant. For example, certain amino acids and their derivatives are desirable as building blocks for surfactants, but the choice of which amino acid to use is far from straightforward. The synthesis of such compounds adds an additional layer of difficulty due to differences in solubility that can be attributed to different elements and moieties present in the same molecule. There remains a need for highly effective surfactants that can be easily synthesized on a commercial scale via a convenient route. Summary of the Invention

[0007] The present disclosure provides derivatives of amino acids that have a branched alkyl structure and exhibit surface active properties. The amino acids may be natural or synthetic amino acids or may be obtained via a ring-opening reaction of molecules such as lactams, e.g. caprolactam. The amino acids may be functionalized to form compounds with surface active properties. Characteristically, these compounds are The compound may have a low critical micelle concentration (CMC) and / or the ability to reduce the surface tension of a liquid.

[0008] The present disclosure provides compounds of formula I, also referred to herein as surfactants:

[0009] [ka]

[0010] In the formula, R 1 is selected from hydrogen, an oxygen atom, and C1-C6 alkyl, which may be substituted with carboxylate, hydroxyl, sulfonyl, or sulfonate; n is an integer from 2 to 5, inclusive; R 2 is C5~C 12 R is alkyl; 3 is C3~C 10 alkyl; the terminal nitrogen is R 4 may be further substituted with, in which case R 4 is selected from hydrogen, an oxygen atom, and C1-C6 alkyl, which may be substituted with carboxylate, hydroxyl, sulfonyl, or sulfonate; and an optional counter ion may be associated with the compound, which, if present, may be selected from the group consisting of chloride, bromide, iodide, and 4-methylbenzenesulfonate.

[0011] The present disclosure further provides compounds of formula II, also referred to herein as surfactants:

[0012] [ka]

[0013] In the formula, R 1 is selected from hydrogen, an oxygen atom, and C1-C6 alkyl, which may be substituted with carboxylate, hydroxyl, sulfonyl, or sulfonate; n is an integer from 2 to 5, inclusive; R 2 is C5~C 12 R is alkyl; 3 is C3~C 10 alkyl; the terminal nitrogen is R 4 may be further substituted with, in which case R 4is selected from hydrogen, an oxygen atom, and C1-C6 alkyl, which may be substituted with carboxylate, hydroxyl, sulfonyl, or sulfonate; and an optional counter ion may be associated with the compound, which, if present, may be selected from the group consisting of chloride, bromide, and iodide.

[0014] One specific compound provided by the present disclosure has the following formula:

[0015] [ka]

[0016] The compound is 6-((2-butyloctyl)oxy)-N,N,N-trimethyl-6-oxohexan-1-aminium iodide having the formula:

[0017] A second specific compound provided by the present disclosure has the following formula:

[0018] [ka]

[0019] The compound is 6-((2-butyloctyl)oxy)-N,N-dimethyl-6-oxohexan-1-aminium 4-methylbenzenesulfonate having the formula:

[0020] A third specific compound provided by the present disclosure has the following formula:

[0021] [ka]

[0022] The compound is 6-((2-butyloctyl)oxy)-N,N-dimethyl-6-oxohexane-1-aminium chloride having the formula:

[0023] A fourth specific compound provided by the present disclosure has the following formula:

[0024] [ka]

[0025] The compound is 4-((6-((2-butyloctyl)oxy)-6-oxohexyl)dimethylammonio)butane-1-sulfonate having the formula:

[0026] A fifth specific compound provided by the present disclosure has the following formula:

[0027] [ka]

[0028] The compound is 2-butyloctyl 6-(dimethylamino)hexanoate N-oxide.

[0029] A sixth specific compound provided by the present disclosure has the following formula:

[0030] [ka]

[0031] The compound is 6-((2-butyloctyl)oxy)-6-oxohexane-1-aminium chloride having the formula:

[0032] The above and other features of the present disclosure, as well as the methods of achieving the same, will become more apparent and better understood by referring to the following description of the embodiments taken in conjunction with the accompanying drawings. [Brief description of the drawings]

[0033] [Figure 1]FIG. 1 shows a plot of surface tension versus concentration measured at pH=7 as described in Example 1B, where the Y-axis represents surface tension (γ) in millinewtons per meter (mN / m) and the X-axis represents concentration (c) in millimoles (mM). [Figure 2A] FIG. 2A shows a plot of surface tension versus concentration measured at pH=7 as described in Example 2B, where the Y-axis represents surface tension (γ) in milliNewtons per meter (mN / m) and the X-axis represents concentration (c) in millimoles (mM). [Figure 2B] FIG. 2B shows a plot of dynamic surface tension as change in surface tension versus time, as described in Example 2C, where the Y-axis represents surface tension in milliNewtons per meter (mN / m) and the X-axis represents surface elapsed time in milliseconds (ms). [Diagram 3] FIG. 3 shows a plot of surface tension versus concentration measured at pH=7 as described in Example 3B, where the Y-axis represents surface tension (γ) in milliNewtons per meter (mN / m) and the X-axis represents concentration (c) in millimoles (mM). [Figure 4A] FIG. 4A shows a plot of surface tension versus concentration measured at pH=7 as described in Example 4B, where the Y-axis represents surface tension (γ) in milliNewtons per meter (mN / m) and the X-axis represents concentration (c) in millimoles (mM). [Figure 4B] FIG. 4B shows a plot of dynamic surface tension as change in surface tension versus time, as described in Example 4C, where the Y-axis represents surface tension in milliNewtons per meter (mN / m) and the X-axis represents surface elapsed time in milliseconds (ms). [Figure 5A] FIG. 5A shows a plot of surface tension versus concentration measured at pH=7 as described in Example 5B, where the Y-axis represents surface tension (γ) in milliNewtons per meter (mN / m) and the X-axis represents concentration (c) in millimoles (mM). [Figure 5B] FIG. 5B shows a plot of dynamic surface tension as change in surface tension versus time, as described in Example 5C, where the Y-axis represents surface tension in milliNewtons per meter (mN / m) and the X-axis represents surface elapsed time in milliseconds (ms). [Figure 6A]FIG. 6A shows a plot of surface tension versus concentration measured at pH=7 as described in Example 6B, where the Y-axis represents surface tension (γ) in milliNewtons per meter (mN / m) and the X-axis represents concentration (c) in millimoles (mM). [Figure 6B] FIG. 6B shows a plot of dynamic surface tension as change in surface tension versus time, as described in Example 6C, where the Y-axis represents surface tension in milliNewtons per meter (mN / m) and the X-axis represents surface elapsed time in milliseconds (ms). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0034] I. Definition As used herein, the phrase "within any range defined between any two of the above values" literally means that any range from any two of the values ​​listed before the phrase may be selected, regardless of whether the values ​​are toward the lower value of the list or toward the higher value of the list. For example, a pair of values ​​may be selected from the two lower values, the two higher values, or a lower value and an upper value.

[0035] As used herein, the term "alkyl" means any saturated carbon chain, which may be straight or branched.

[0036] As used herein, the phrase "surface active" means that the associated compound is capable of lowering the surface tension of the medium in which it is dissolved and / or the interfacial tension with other phases and therefore may adsorb to air-liquid interfaces and / or other interfaces. The term "surfactant" may be applied to such compounds.

[0037] With respect to terms of imprecision, the terms "about" and "approximately" may be used interchangeably and may be used to mean a measurement that includes the stated measurement and includes any measurement that is reasonably close to the stated measurement. A measurement that is reasonably close to the stated measurement deviates from the stated measurement by a reasonably small amount that is understood and readily ascertained by one of ordinary skill in the relevant art. Such deviations may be attributed, for example, to measurement error or small adjustments made to optimize performance. In cases where one of ordinary skill in the relevant art would determine that values ​​for such reasonably small differences are not readily ascertainable, the terms "about" and "approximately" may be used to mean plus or minus the stated value. This may be understood to mean 10%.

[0038] II. Surfactant Formula The present disclosure provides derivatives of amino acids having branched alkyl structures. The amino acids may be natural or synthetic amino acids, or may be obtained from ring-opening reactions of lactams such as caprolactam. The compounds of the present disclosure have been shown to have surface active properties and may be used, for example, as surfactants and wetting agents. In particular, the present disclosure provides compounds of formula I, as shown below:

[0039] [ka]

[0040] In the formula, R 1 is selected from hydrogen, an oxygen atom, and C1-C6 alkyl, which may be substituted with carboxylate, hydroxyl, sulfonyl, or sulfonate; n is an integer from 2 to 5, inclusive; R 2 is C5~C 12 R is alkyl; 3 is C3~C 10 alkyl; the terminal nitrogen is R 4 may be further substituted with, in which case R 4is selected from hydrogen, an oxygen atom, and C1-C6 alkyl, which may be substituted with carboxylate, hydroxyl, sulfonyl, or sulfonate; and an optional counter ion may be associated with the compound, which, if present, may be selected from the group consisting of chloride, bromide, iodide, and 4-methylbenzenesulfonate.

[0041] The present disclosure further provides compounds of formula II, also referred to herein as surfactants:

[0042] [ka]

[0043] In the formula, R 1 is selected from hydrogen, an oxygen atom, and C1-C6 alkyl, which may be substituted with carboxylate, hydroxyl, sulfonyl, or sulfonate; n is an integer from 2 to 5, inclusive; R 2 is C5~C 12 R is alkyl; 3 is C3~C 10 alkyl; the terminal nitrogen is R 4 may be further substituted with, in which case R 4 is selected from hydrogen, an oxygen atom, and C1-C6 alkyl, which may be substituted with carboxylate, hydroxyl, sulfonyl, or sulfonate; and an optional counter ion may be associated with the compound, which, if present, may be selected from the group consisting of chloride, bromide, and iodide.

[0044] One specific compound provided by the present disclosure has the following formula:

[0045] [ka]

[0046] The compound is 6-((2-butyloctyl)oxy)-N,N,N-trimethyl-6-oxohexan-1-aminium iodide having the formula:

[0047] A second specific compound provided by the present disclosure has the following formula:

[0048] [ka]

[0049] The compound is 6-((2-butyloctyl)oxy)-N,N-dimethyl-6-oxohexan-1-aminium 4-methylbenzenesulfonate having the formula:

[0050] A third specific compound provided by the present disclosure has the following formula:

[0051] [ka]

[0052] The compound is 6-((2-butyloctyl)oxy)-N,N-dimethyl-6-oxohexane-1-aminium chloride having the formula:

[0053] A fourth specific compound provided by the present disclosure has the following formula:

[0054] [ka]

[0055] The compound is 4-((6-((2-butyloctyl)oxy)-6-oxohexyl)dimethylammonio)butane-1-sulfonate having the formula:

[0056] A fifth specific compound provided by the present disclosure has the following formula:

[0057] [ka]

[0058] The compound is 2-butyloctyl 6-(dimethylamino)hexanoate N-oxide.

[0059] In the above structures, the "N→O" designation is intended to mean a non-ionic bonding interaction between the nitrogen and oxygen.

[0060] A sixth specific compound provided by the present disclosure has the following formula:

[0061] [ka]

[0062] The compound is 6-((2-butyloctyl)oxy)-6-oxohexane-1-aminium chloride having the formula:

[0063] III.Synthesis The surfactant compound of the present invention can be synthesized by various methods.One such method includes ring-opening lactam, which may be N-alkylated lactam, to obtain an amino acid having an N-terminus and a C-terminus.The C-terminus can then be reacted with alcohol under acidic conditions to obtain an amino acid ester.The N-terminus of the amino acid can be reacted with an alkylating agent to obtain a quaternary amine salt, or the N-terminus of the amino acid ester can be reacted with an acid to obtain a quaternary amine salt.

[0064] Alternatively, the method may include ring-opening the lactam to obtain an amino acid having an N-terminus and a C-terminus. The N-terminus may then be reacted with an alkylating agent to obtain a tertiary amine. The C-terminus may then be reacted with an alcohol under acidic conditions to obtain an amino acid ester. The N-terminus of the amino acid may be reacted with an alkylating agent to obtain a quaternary amine salt, or the N-terminus of the amino acid ester may be reacted with an acid to obtain a quaternary amine salt.

[0065] The amino acids may be natural or synthetic, or may be derived from the ring-opening reaction of lactams such as, for example, propiolactam, butyrolactam, valerolactam, and caprolactam. The ring-opening reaction may be acid or alkali catalyzed, an example of an acid catalyzed reaction for caprolactam is shown in Scheme 1 below.

[0066] [ka]

[0067] The amino acid may have as few as two or as many as five carbons between the N-terminus and the C-terminus. The alkyl chain may be branched or straight. The alkyl chain may be interrupted by nitrogen, oxygen, or sulfur. The alkyl chain may be further substituted with one or more substituents selected from the group consisting of hydroxyl, amino, amido, sulfonyl, sulfonate, carboxyl, and carboxylate. The N-terminal nitrogen may be acylated or alkylated with one or more alkyl groups. For example, the amino acid may be 6-(dimethylamino)hexanoic acid.

[0068] The amino acid may be further elaborated as shown in Scheme 2 below, where R, R', and R'' may be hydrogen or C1-C6 alkyl, and R 2 is C5~C 12 may be alkyl, R 3 is C3~C 10 For example, amino acids may undergo an esterification reaction in which the amino acid is treated with an alcohol under acidic conditions to give an amino acid ester.

[0069] [ka]

[0070] As shown in Scheme 3 below, the resulting amino acid ester can then be alkylated or protonated to give an ammonium salt. Alkylation can be achieved by treatment with an alkylating agent such as methyl iodide in the presence of a base such as sodium carbonate to give a quaternary amine salt, with the counterion depending on the alkylating agent used. For example, treatment with methyl iodide gives the iodide salt of a quaternary ammonium species. Protonation can be achieved by treating the amino acid ester with an acid such as hydrochloric acid. The type of acid determines the counter ion present in the salt. For example, treatment with hydrochloric acid results in the chloride salt of the ammonium species.

[0071] [ka]

[0072] IV. Surfactant properties The compounds of the present disclosure exhibit surface active properties. These properties can be measured and expressed by various methods. One way that surfactants can be expressed is by the critical micelle concentration (CMC) of the molecule. CMC can be defined as the concentration of surfactant that forms micelles, and at a higher concentration, any additional surfactant is incorporated into the micelle.

[0073] As the surfactant concentration increases, the surface tension decreases. When the surface is completely covered with surfactant molecules, micelles start to form. This point represents the CMC, or minimum surface tension. Adding more surfactant does not further affect the surface tension. The CMC can therefore be measured by observing the change in surface tension as a function of surfactant concentration. One such method for measuring this value is the Wilhelmy plate method. A Wilhelmy plate is usually a thin iridium-platinum plate attached to a balance by wires and positioned perpendicular to the air-liquid interface. The balance is used to measure the force exerted on the plate by wetting. This value is then used to calculate the surface tension (γ) according to equation 1: Equation 1: γ = F / l cosθ where l is equal to the wetted perimeter (2w+2d, where w and d are the thickness and width of the plate, respectively), and for cosθ, the contact angle between the liquid and the plate is assumed to be 0 in the absence of existing literature values.

[0074] Another parameter used to evaluate the performance of surfactants is the dynamic surface tension. Dynamic surface tension is the value of the surface tension over time for a particular surface or interface. For liquids to which surfactants have been added, this may differ from the equilibrium value. Immediately after the surface is created, the surface tension is equal to that of the pure liquid. As mentioned above, surfactants are surface tension reducers, so the surface tension decreases until it reaches an equilibrium value. The time required to reach equilibrium depends on the diffusion and adsorption rates of the surfactant.

[0075] One way to measure dynamic surface tension is with a maximum bubble pressure tensiometer. This device measures the maximum internal pressure of a bubble formed in a liquid by a capillary. The measured value corresponds to the surface tension at a certain surface time, which is the time from the start of bubble formation to the maximum pressure. The dependence of surface tension on surface time can be measured by varying the rate at which the bubbles are generated.

[0076] Surface active compounds can also be evaluated by their wetting ability on solid substrates, measured by contact angle. When a liquid drop contacts a solid surface in a third medium, such as air, a three-phase line is formed between the liquid, the gas, and the solid. The angle between the surface and the unit vector of surface tension, which plays a role in the three-phase line and is tangent to the drop, is expressed as the contact angle. The contact angle (also known as the wetting angle) is a measure of the wettability of a solid by a liquid. In the case of complete wetting, the liquid wetting the solid It spreads completely on the surface and has a contact angle of 0°. Wetting properties are typically measured at concentrations between 1 and 10 x CMC for a given compound, however, as it is not a concentration dependent property, measurements of wetting properties may be measured at higher or lower concentrations.

[0077] In one method, an optical contact angle goniometer can be used to measure contact angles. This instrument uses a digital camera and software to determine the contact angle by analyzing the contour shape of a stationary drop of liquid on a surface.

[0078] Potential applications for the surface active compounds of the present disclosure include formulations for use as shampoos, hair conditioners, detergents, spot free rinse solutions, floor and carpet cleaners, cleaners for graffiti removal, wetting agents for crop protection, adjuvants for crop protection, and wetting agents for aerosol spray coatings.

[0079] Those skilled in the art understand that different compounds can be used with different substrates in different applications, because small differences between compounds can lead to significantly different surfactant properties.Small changes in the hydrophobic part of surfactant, such as the difference in the carbon number of alkyl chain, the presence of branched alkyl chain, the number of branches of branched alkyl chain, and the carbon number in each branch of branched alkyl chain, can lead to different surfactant properties.Similarly, in the case of cationic and anionic surfactants, different counter ions can significantly change the surfactant properties of compound.

[0080] The compounds are effective as surface active agents and are useful as wetting or foaming agents, dispersing agents, emulsifying agents, and detergents, among other uses.

[0081] The amount of a compound disclosed herein used in the formulation can be as low as about 0.001%, about 0.05%, about 0.1%, about 0.5%, about 1%, about 2%, or about 5% by weight, or as high as about 8%, about 10%, about 15%, about 20%, or about 25% by weight, or within any range defined between any two of the above values.

[0082] The following non-limiting examples are provided to illustrate the different properties of different surfactants. EXAMPLES

[0083] Nuclear magnetic resonance (NMR) spectroscopy was performed on a Bruker 500 MHz spectrometer. The critical micelle concentration (CMC) was determined by the Wilhelmy plate method using a tensiometer (DCAT 11, DataPhysics Instruments GmbH) equipped with a Pt-Ir plate at 23 °C. The dynamic surface tension was determined using a maximum bubble pressure tensiometer (Kruss BP100, Kruss GmbH) at 23 °C. The contact angle was determined using an optical contact angle goniometer (OCA 15 Pro, DataPhysics GmbH) equipped with a digital camera.

[0084] Example 1a: Synthesis of 6-((2-butyloctyl)oxy)-N,N,N-trimethyl-6-oxohexan-1-aminium iodide 2-Butyloctyl 6-(dimethylamino)hexanoate (2.04 mmol, 700 mg) was dissolved in acetonitrile (10 mL). Sodium carbonate (2.44 mmol, 259 mg) was added and the mixture was stirred at room temperature for 10 min. Methyl iodide (6.12 mmol, 0.38 mL) was added and the mixture was heated to 40° C. for 24 h and then cooled to room temperature. The mixture was filtered and the solvent removed in vacuo to give 6-((2-butyloctyl)oxy)-N,N,N-trimethyl-6-oxohexan-1-aminium iodide as a yellow solid. The compound was obtained in 90% yield. 1 H NMR(500MHz,DMSO) δ3.93(d,J=5.7Hz,2H),3.29-3.22(m,2H),3.04(s,9H),2.34(t,J=7.4Hz,2H),1.73-1.53(m,5H),1.33-1.25(m,18H),0.88-0.85(m,6H).

[0085] Example 1b: Identifying the Critical Micelle Concentration (CMC) The critical micelle concentration (CMC) of 6-((2-butyloctyl)oxy)-N,N,N-trimethyl-6-oxohexan-1-aminium iodide from Example 1a was tested. From the plot of results shown in FIG. 1, it is clear that at concentrations as high as 10 mg / mL, the CMC value cannot be clearly identified and the surface tension asymptotically approaches a value of about 27 mN / m. FIG. 1 is a plot of these results, showing surface tension versus concentration. From the plot of results, it is clear that the surface tension at the CMC is about 27 mN / m or less.

[0086] Example 2a: Synthesis of 6-((2-butyloctyl)oxy)-N,N-dimethyl-6-oxohexan-1-aminium 4-methylbenzenesulfonate 6-(Dimethylamino)hexanoic acid was treated with 2-butyloctan-1-ol and p-toluenesulfonic acid in benzene for 12 hours at 120° C. 6-((2-butyloctyl)oxy)-N,N-dimethyl-6-oxohexan-1-aminium 4-methylbenzenesulfonate was isolated as a white waxy solid and recrystallized from acetone in 49% yield. 1 H NMR(500MHz,DMSO) δ7.48(dd,J=8.4,0.6Hz,2H),7.12(dd,J=8.4,0.6Hz,1H),3.93(d,J=5.7Hz,2H),3.02-3.00(m,2H),2.76 (d,J=5.0Hz,6H),2.37-2.25(m,6H),1.59-1.53(m,5H),1.25-1.29(m,18H),0.87(td,J=6.8,2.7Hz,6H).

[0087] Example 2b: Identifying the Critical Micelle Concentration (CMC) The critical micelle concentration (CMC) of 6-((2-butyloctyl)oxy)-N,N-dimethyl-6-oxohexan-1-aminium 4-methylbenzenesulfonate from Example 2a was tested. From the surface tension with concentration in water, the CMC was determined to be about 0.97 mmol. The minimum surface tension plateau value achievable with this surfactant is about 27 mN / m, i.e., 27 mN / m±3 mN / m. FIG. 2A is a plot of these results, showing surface tension versus concentration. From the resulting plot, the surface tension at the CMC is about 30 mN / m or less.

[0088] Example 2c: Determination of dynamic surface tension The dynamic surface tension of 6-((2-butyloctyl)oxy)-N,N-dimethyl-6-oxohexan-1-aminium 4-methylbenzenesulfonate from Example 2a was determined with a maximum bubble pressure tensiometer, which measures the change in surface tension of a freshly created air-water interface over time. Figure 2B shows a plot of surface tension versus time, which shows that in the time interval of 10-100 ms, the surface tension drops rapidly from about 46 mN / m to about 30 mN / m. In the time interval of 100-8000 ms, the surface tension drops slowly from 30 mN / m to about 27 mN / m, asymptotically approaching the saturation value of surface tension at the CMC.

[0089] Example 2d: Identification of wetting properties In addition to surface tension and surface kinetics, the wetting properties of 6-((2-butyloctyl)oxy)-N,N-dimethyl-6-oxohexane-1-aminium 4-methylbenzenesulfonate from Example 2a were tested on various surfaces. For example, hydrophobic substrates such as polyethylene-HD exhibit a surface wetting with a contact angle of 24.3°. On oleophobic and hydrophobic substrates such as Teflon, the measured contact angle was 48.2°, much lower than the contact angle of water of 119° (Table 1).

[0090] [Table 1]

[0091] Example 3a: Synthesis of 6-((2-butyloctyl)oxy)-N,N-dimethyl-6-oxohexane-1-aminium chloride 2-Butyloctyl 6-(dimethylamino)hexanoate was treated with one equivalent of hydrochloric acid to give 6-((2-butyloctyl)oxy)-N,N-dimethyl-6-oxohexan-1-aminium chloride.

[0092] Example 3b: Identifying the Critical Micelle Concentration (CMC) The critical micelle concentration (CMC) of 6-((2-butyloctyl)oxy)-N,N-dimethyl-6-oxohexane-1-aminium chloride from Example 3a was tested. From the surface tension varying with concentration in water, the CMC was determined to be about 27.47 mmol. The minimum surface tension achievable with this surfactant is about 29 mN / m, i.e., 29 mN / m±3 mN / m. FIG. 3 is a plot of these results, showing surface tension versus concentration. From the resulting plot, it is clear that at concentrations as high as 27.4 mmol, the CMC value cannot be clearly determined, and the surface tension asymptotically approaches a value of about 29 mN / m.

[0093] Example 4a: Synthesis of 4-((6-((2-butyloctyl)oxy)-6-oxohexyl)dimethylammonio)butane-1-sulfonate 2-Butyloctyl 6-(dimethylamino)hexanoate (2.04 mmol, 700 mg) was dissolved in ethyl acetate (30 mL). 1,4-butanesultone (3.06 mmol, 0.31 mL) was added. The mixture was heated to reflux for 12 h, followed by evaporation of the solvent. The resulting white waxy solid was washed with acetone to give 4-((6-((2-butyloctyl)oxy)-6-oxohexyl)dimethylammonio)butane-1-sulfonate in 89% yield. 1H NMR(500MHz,DMSO) δ3.93(d,J=5.7Hz,2H),3.30-3.28(m,4H),2.97(s,3H),2.49-2.43(m,2H),2. 34(t,J=7.4Hz,2H),1.96-1.76(m,9H),1.27-1.25(m,18H),0.88-0.85(m,6H).

[0094] Example 4b: Identifying the Critical Micelle Concentration (CMC) The critical micelle concentration (CMC) of 4-((6-((2-butyloctyl)oxy)-6-oxohexyl)dimethylammonio)butane-1-sulfonate from Example 4a was tested. From the surface tension with concentration in water, the CMC was determined to be about 0.54 mmol. The minimum surface tension plateau value achievable with this surfactant is about 32 mN / m, i.e., 32 mN / m±3 mN / m. FIG. 4A is a plot of these results, showing surface tension versus concentration. From the resulting plot, the surface tension at the CMC is about 32 mN / m or less.

[0095] Example 4c: Determination of dynamic surface tension The dynamic surface tension of 4-((6-((2-butyloctyl)oxy)-6-oxohexyl)dimethylammonio)butane-1-sulfonate from Example 4a was determined with a maximum bubble pressure tensiometer, which measures the change in surface tension of a freshly created air-water interface over time. Figure 4B shows a plot of surface tension versus time, which shows that in the time interval from 10 to 100 ms, the surface tension drops rapidly from about 66 mN / m to about 36 mN / m. In the time interval from 100 to 8000 ms, the surface tension drops slowly from 36 mN / m to about 32 mN / m, asymptotically approaching the saturation value of surface tension at the CMC.

[0096] Example 4d: Identification of wetting properties In addition to surface tension and surface kinetics, the wetting properties of 4-((6-((2-butyloctyl)oxy)-6-oxohexyl)dimethylammonio)butane-1-sulfonate from Example 4a were tested on various surfaces. For example, a hydrophobic substrate such as polyethylene-HD exhibits a surface wetting with a contact angle of 44.4°. On an oleophobic and hydrophobic substrate such as Teflon, the measured contact angle was 62.2°, much lower than the contact angle of water of 119° (Table 2).

[0097] [Table 2]

[0098] Example 5a: Synthesis of 2-butyloctyl 6-(dimethylamino)hexanoate N-oxide 2-Butyloctyl 6-(dimethylamino)hexanoate was treated with hydrogen peroxide in water at 70° C. for 24 hours to give 2-butyloctyl 6-(dimethylamino)hexanoate N-oxide as an oil in 90% yield. 1 H NMR(500MHz,DMSO) δ3.93(d,J=5.7Hz,2H),3.30-3.28(m,4H),2.97(s,3H),2.49-2.43(m,2H),2. 34(t,J=7.4Hz,2H),1.96-1.76(m,9H),1.27-1.25(m,18H),0.88-0.85(m,6H).

[0099] Example 5b: Identifying the Critical Micelle Concentration (CMC) The critical micelle concentration (CMC) of 2-butyloctyl 6-(dimethylamino)hexanoate N-oxide from Example 5a was tested. From the surface tension with concentration in water, the CMC was determined to be about 0.29 mmol. The plateau value of the minimum surface tension achievable with this surfactant is about 28 mN / m, i.e., 28 mN / m±3 mN / m. Figure 5A is a plot of these results, showing surface tension versus concentration. From the resulting plot, the surface tension at the CMC is about 28 mN / m or less.

[0100] Example 5c: Determination of dynamic surface tension The dynamic surface tension of 2-butyloctyl 6-(dimethylamino)hexanoate N-oxide from Example 5a was determined with a maximum bubble pressure tensiometer, which measures the change in surface tension of a freshly created air-water interface over time. Figure 5B shows a plot of surface tension versus time, which shows that in the time interval of 10-1000 ms, the surface tension drops rapidly from about 60 mN / m to about 30 mN / m. In the time interval of 1000-8000 ms, the surface tension drops slowly from 30 mN / m to about 28 mN / m, asymptotically approaching the saturation value of surface tension at the CMC.

[0101] Example 5d: Identification of wetting properties In addition to surface tension and surface kinetics, the wetting properties of 2-butyloctyl 6-(dimethylamino)hexanoate N-oxide from Example 5a were tested on various surfaces. For example, hydrophobic substrates such as polyethylene-HD exhibit a surface wetting with a contact angle of 31.6°. On oleophobic and hydrophobic substrates such as Teflon, the measured contact angle was 41.5°, much lower than the contact angle of water, 119° (Table 3).

[0102] [Table 3]

[0103] Example 6a: Synthesis of 6-((2-butyloctyl)oxy)-6-oxohexane-1-aminium chloride 2-Butyloctyl 6-(dimethylamino)hexanoate was treated with one equivalent of hydrochloric acid.

[0104] Example 6b: Identifying the Critical Micelle Concentration (CMC) The critical micelle concentration (CMC) of 6-((2-butyloctyl)oxy)-6-oxohexane-1-aminium chloride from Example 6a was tested. From the change in surface tension with concentration in water, the CMC was determined to be about 0.15 mmol. The plateau value of the minimum surface tension achievable with this surfactant is about 27 mN / m, i.e., 27 mN / m±3 mN / m. Figure 6A is a plot of these results, showing surface tension versus concentration. From the resulting plot, the surface tension at CMC is approximately 30 mN / m or less.

[0105] Example 6c: Determination of dynamic surface tension The dynamic surface tension of 6-((2-butyloctyl)oxy)-6-oxohexane-1-aminium chloride from Example 6a was determined with a maximum bubble pressure tensiometer, which measures the change in surface tension of a freshly created air-water interface over time. Figure 6B shows a plot of surface tension versus time, showing a slow decrease in surface tension from about 69 mN / m to about 29 mN / m over the time interval from 10 to 8000 ms, approaching a saturation value of surface tension at the CMC, with a slight plateau of about 49 mN / m at a surface lapse time of 1000 ms.

[0106] Example 6d: Identification of wetting properties In addition to surface tension and surface kinetics, the wetting properties of 6-((2-butyloctyl)oxy)-6-oxohexane-1-aminium chloride from Example 6a were tested on various surfaces. For example, hydrophobic substrates such as polyethylene-HD exhibit a surface wetting with a contact angle of 25.8°. On oleophobic and hydrophobic substrates such as Teflon, the measured contact angle was 48.7°, much lower than the contact angle of water, 119° (Table 4).

[0107] [Table 4]

[0108] Aspects Aspect 1 is a compound of the formula:

[0109] [ka]

[0110] In the formula, R 1 is selected from hydrogen, an oxygen atom, and C1-C6 alkyl, which may be substituted with carboxylate, hydroxyl, sulfonyl, or sulfonate; n is an integer from 2 to 5, inclusive; R 2 is C5~C 12 R is alkyl; 3 is C3~C 10 alkyl; the terminal nitrogen is R 4 may be further substituted with, in which case R 4 is selected from hydrogen, an oxygen atom, and C1-C6 alkyl, which may be substituted with carboxylate, hydroxyl, sulfonyl, or sulfonate; and an optional counter ion may be associated with the compound, which, if present, may be selected from the group consisting of chloride, bromide, iodide, and 4-methylbenzenesulfonate.

[0111] Aspect 2 is a compound having the following formula:

[0112] [ka]

[0113] The compound according to embodiment 1 is 6-((2-butyloctyl)oxy)-N,N,N-trimethyl-6-oxohexan-1-aminium iodide having the formula:

[0114] Aspect 3 is a compound according to aspect 2, having a critical micelle concentration (CMC) in aqueous solution of about 21.30 mmol.

[0115] Aspect 4 is a compound having the formula:

[0116] [ka]

[0117] The compound according to embodiment 1 is 6-((2-butyloctyl)oxy)-N,N-dimethyl-6-oxohexan-1-aminium 4-methylbenzenesulfonate having the formula:

[0118] Example 5 is a compound according to Example 4, having a critical micelle concentration (CMC) in aqueous solution of about 0.97 mmol.

[0119] Aspect 6 is the compound according to Aspect 4 or Aspect 5, which has a surface tension of 30 mN / m or less in an aqueous solution at a surface transit time of 100 ms or more.

[0120] Aspect 7 is a compound having the formula:

[0121] [ka]

[0122] The compound according to embodiment 1 is 6-((2-butyloctyl)oxy)-N,N-dimethyl-6-oxohexan-1-aminium chloride having the formula:

[0123] Example 8 is a compound according to example 7, having a critical micelle concentration (CMC) in aqueous solution of about 27.47 mmol.

[0124] Aspect 9 is a compound having the formula:

[0125] [ka]

[0126] The compound according to embodiment 1 is 4-((6-((2-butyloctyl)oxy)-6-oxohexyl)dimethylammonio)butane-1-sulfonate having the formula:

[0127] Example 10 is a compound according to example 9, having a critical micelle concentration (CMC) in aqueous solution of about 0.54 mmol.

[0128]

[0033] Aspect 11 is the compound according to aspect 9 or aspect 10, having a surface tension in aqueous solution of 36 mN / m or less at a surface transit time of 100 ms or more.

[0129] Aspect 12 is a compound having the formula:

[0130] [ka]

[0131] The compound according to embodiment 1 is 2-butyloctyl 6-(dimethylamino)hexanoate N-oxide having the formula:

[0132] Example 13 is a compound according to example 12, having a critical micelle concentration (CMC) in aqueous solution of about 0.29 mmol.

[0133] Aspect 14 is the compound according to aspect 12 or aspect 13, having a surface tension in aqueous solution of 30 mN / m or less at a surface transit time of 1000 ms or more.

[0134] Aspect 15 is a compound of the formula:

[0135] [ka]

[0136] In the formula, R 1 is selected from hydrogen, an oxygen atom, and C1-C6 alkyl, which may be substituted with carboxylate, hydroxyl, sulfonyl, or sulfonate; n is an integer from 2 to 5, inclusive; R 2 is C5~C 12 R is alkyl; 3 is C3~C 10 alkyl; the terminal nitrogen is R 4may be further substituted with, in which case R 4 is selected from hydrogen, an oxygen atom, and C1-C6 alkyl, which may be substituted with carboxylate, hydroxyl, sulfonyl, or sulfonate; and an optional counter ion may be associated with the compound, which, if present, may be selected from the group consisting of chloride, bromide, and iodide.

[0137] Aspect 16 is a compound having the formula:

[0138] [ka]

[0139] The compound according to embodiment 15 is 6-((2-butyloctyl)oxy)-6-oxohexane-1-aminium chloride having the formula:

[0140] Example 17 is a compound according to example 16, having a critical micelle concentration (CMC) in aqueous solution of about 0.15 mmol.

[0141]

[0033] Aspect 18 is the compound according to aspect 16 or aspect 17, having a surface tension in aqueous solution of 49 mN / m or less at a surface transit time of 1000 ms or more.

[0142] A nineteenth aspect is a compound comprising a medium and a surfactant of the formula:

[0143] [ka]

[0144] In the formula, R 1 is selected from hydrogen, an oxygen atom, and C1-C6 alkyl, which may be substituted with carboxylate, hydroxyl, sulfonyl, or sulfonate; n is an integer from 2 to 5, inclusive; R 2 is C5~C 12 Alki R 3 is C3~C 10 alkyl; the terminal nitrogen is R 4 may be further substituted with, in which case R 4 is selected from hydrogen, an oxygen atom, and C1-C6 alkyl, which may be substituted with carboxylate, hydroxyl, sulfonyl, or sulfonate; and an optional counterion may be associated with the compound, which counterion, if present, may be selected from the group consisting of chloride, bromide, iodide, and 4-methylbenzenesulfonate.

[0145] Example 20 is the composition of example 19, wherein the medium is water.

[0146] A twenty-first aspect is a composition comprising a medium and a surfactant of the following formula:

[0147] [ka]

[0148] In the formula, R 1 is selected from hydrogen, an oxygen atom, and C1-C6 alkyl, which may be substituted with carboxylate, hydroxyl, sulfonyl, or sulfonate; n is an integer from 2 to 5, inclusive; R 2 is C5~C 12 R is alkyl; 3 is C3~C 10 alkyl; the terminal nitrogen is R 4 may be further substituted with, in which case R 4is selected from hydrogen, an oxygen atom, and C1-C6 alkyl, which may be substituted with carboxylate, hydroxyl, sulfonyl, or sulfonate; and an optional counterion may be associated with the compound, which counterion, if present, may be selected from the group consisting of chloride, bromide, and iodide.

[0149] Example 22 is the composition of example 21, wherein the medium is water.

Claims

1. A compound of the formula: 【Chemistry 1】 In the formula, R １ is selected from hydrogen and oxygen atoms, n is 5; R ２ is C ５ ~C １２ is alkyl, R ３ is C ３ ~C １０ is alkyl, The terminal nitrogen is R ４ may be further substituted with, in which case R ４ represents hydrogen, oxygen, and C １ ~C ６ alkyl, １ ~C ６ The alkyl may be substituted with a carboxylate, hydroxyl, sulfonyl, or sulfonate; and an optional counter ion may be associated with said compound, said counter ion, if present, being selected from the group consisting of chloride, bromide, iodide, and 4-methylbenzenesulfonate.

2. The following formula: 【Chemistry 2】 2. The compound of claim 1, which is 6-((2-butyloctyl)oxy)-N,N-dimethyl-6-oxohexane-1-aminium 4-methylbenzenesulfonate having the formula:

3. The compound of claim 2, having a critical micelle concentration (CMC) in aqueous solution of 0.97 mmol.

4. The compound according to claim 2, having a surface tension in aqueous solution of 30 mN / m or less at a surface transit time of 100 ms or more.

5. The following formula: 【Chemistry 3】 2. The compound of claim 1, which is 6-((2-butyloctyl)oxy)-N,N-dimethyl-6-oxohexane-1-aminium chloride having the formula:

6. The compound of claim 5, having a critical micelle concentration (CMC) in aqueous solution of 27.47 mmol.

7. The following formula: 【Chemistry 4】 2. The compound of claim 1, which is 4-((6-((2-butyloctyl)oxy)-6-oxohexyl)dimethylammonio)butane-1-sulfonate having the formula:

8. The compound of claim 7, having a critical micelle concentration (CMC) in aqueous solution of 0.54 mmol.

9. The compound according to claim 7, having a surface tension in aqueous solution of 36 mN / m or less at a surface transit time of 100 ms or more.

10. The following formula: 【Chemistry 5】 2. The compound of claim 1, which is 2-butyloctyl 6-(dimethylamino)hexanoate N-oxide having the formula:

11. The compound of claim 10, having a critical micelle concentration (CMC) in aqueous solution of 0.29 mmol.

12. The compound according to claim 10, having a surface tension of 30 mN / m or less in aqueous solution at a surface transit time of 1000 ms or more.

13. A compound of the formula: 【Chemistry 6】 In the formula, R １ represents hydrogen, oxygen, and C １ ~C ６ alkyl, １ ~C ６ The alkyl may be substituted with a carboxylate, hydroxyl, sulfonyl, or sulfonate; n is 5; R ２ is C ５ ~C １２ is alkyl, R ３ is C ３ ~C １０ is alkyl, The terminal nitrogen is R ４ may be further substituted with, in which case R ４ represents hydrogen, oxygen, and C １ ~C ６ alkyl, １ ~C ６ The alkyl may be substituted with a carboxylate, hydroxyl, sulfonyl, or sulfonate; and an optional counter ion may be associated with said compound, said counter ion, if present, being selected from the group consisting of chloride, bromide, and iodide.

14. The following formula: 【Chemistry 7】 14. The compound of claim 13, which is 6-((2-butyloctyl)oxy)-6-oxohexane-1-aminium chloride having the formula:

15. 15. The compound of claim 14, having a critical micelle concentration (CMC) in aqueous solution of 0.15 mmol.

16. The compound according to claim 14, having a surface tension in aqueous solution of 49 mN / m or less at a surface transit time of 1000 ms or more.

17. Media, and A surfactant of the formula: 【Chemistry 8】 In the formula, R １ represents hydrogen, oxygen, and C １ ~C ６ alkyl, １ ~C ６ The alkyl may be substituted with a carboxylate, hydroxyl, sulfonyl, or sulfonate; n is 5; R ２ is C ５ ~C １２ is alkyl, R ３ is C ３ ~C １０ is alkyl, The terminal nitrogen is R ４ may be further substituted with, in which case R ４ represents hydrogen, oxygen, and C １ ~C ６ alkyl, １ ~C ６ The alkyl may be substituted with a carboxylate, hydroxyl, sulfonyl, or sulfonate; and an optional counter ion may be associated with said compound, said counter ion, if present, being selected from the group consisting of chloride, bromide, iodide, and 4-methylbenzenesulfonate; A liquid composition comprising:

18. The composition of claim 17, wherein the medium is water.

19. Media, and A surfactant of the formula: 【Chemistry 9】 In the formula, R １ represents hydrogen, oxygen, and C １ ~C ６ alkyl, １ ~C ６ The alkyl may be substituted with a carboxylate, hydroxyl, sulfonyl, or sulfonate; n is 5; R ２ is C ５ ~C １２ is alkyl, R ３ is C ３ ~C １０ is alkyl, The terminal nitrogen is R ４ may be further substituted with, in which case R ４ represents hydrogen, oxygen, and C １ ~C ６ alkyl, １ ~C ６ The alkyl may be substituted with a carboxylate, hydroxyl, sulfonyl, or sulfonate; and a counter ion, which may be associated with said compound and which, if present, is selected from the group consisting of chloride, bromide, and iodide; A liquid composition comprising:

20. 20. The composition of claim 19, wherein the medium is water.

Images