Branched amino acid surfactants

Abstract

The present disclosure provides derivatives of amino acids having branched alkyl structures and surface active properties. The amino acids can be naturally occurring or synthetic, or they can be obtained via ring opening reactions of molecules such as lactams (e.g., caprolactam). The amino acids can be functionalized to form compounds that are surface active and have favorable surfactant properties. The compounds of the present disclosure have low critical micelle concentrations (CMC) as well as excellent ability to lower the surface tension of liquids.

Description

[0001] This application is a divisional application of the invention patent application entitled "branched-chain amino acid surfactant" with application number 202180061726.4, filed on July 1, 2021.

[0002] Cross-reference to related applications This application claims priority to U.S. Provisional Application No. 63 / 049,726, filed July 9, 2020, the contents of which are incorporated herein by reference in their entirety. Technical Field

[0003] This disclosure relates to amino acid derivatives and methods for synthesizing them, wherein the amino acid derivatives include branched alkyl structures and have surface-active properties. Background of the Invention Surfactants (molecules with surface-active properties) are an important class of molecules with highly sought-after characteristics. Surfactants can be uncharged, zwitterionic, cationic, or anionic. Typically, 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 between two liquids, a liquid and a gas, or a liquid and a solid. In the case of the water-oil interface, 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 surfactants disrupts the intermolecular interactions between water molecules, replacing them with weaker interactions between water molecules and the surfactant. This leads to a reduction in surface tension and can also be used to stabilize interfaces.

[0004] At sufficiently high concentrations, surfactants can form aggregates to limit the exposure of their hydrophobic tails to polar solvents. One such aggregate is a micelle, in which molecules are arranged in a spherical shape with the hydrophobic tails on the inside and the hydrophilic heads on the outside to interact with the polar solvent. The effect of a given compound on surface tension and the concentration at which it forms micelles can be considered defining characteristics of a surfactant.

[0005] Surfactants are widely used in commercial formulations ranging from detergents and hair care products to cosmetics. Compounds with surface-active properties are particularly used as soaps, detergents, lubricants, wetting agents, foaming agents, and spreading agents. Therefore, there is a need to identify and synthesize such compounds.

[0006] However, judging solely from its structure, it may be difficult to predict whether a given compound will possess surface-active properties, let alone other important characteristics such as interfacial adsorption kinetics, achievable minimum surface tension, and / or the ability to wet hydrophobic and / or oleophobic surfaces, which are also essential for a compound to become a useful surfactant. Certain amino acids and their derivatives are desirable components for surfactants, for example, but the choice of which amino acid to use is far from straightforward. The solubility differences caused by different elements and parts present in the same molecule add another layer of difficulty to the synthesis of such compounds. There remains a need for highly efficient surfactants that can be easily synthesized on a commercial scale via simple routes. Summary of the Invention

[0007] This disclosure provides derivatives of amino acids having branched alkyl structures and exhibiting surface-active properties. The amino acids can be naturally occurring or synthetic, or they can be obtained via ring-opening reactions of molecules such as lactams (e.g., caprolactam). Amino acids can be functionalized to form compounds with surface-active properties. Characteristically, these compounds may have a low critical micelle concentration (CMC) and / or the ability to reduce the surface tension of liquids.

[0008] This disclosure provides compounds of formula I, also referred to herein as surfactants: Where R 1 Selected from hydrogen, oxygen atoms, and C1-C6 alkyl groups, wherein the C1-C6 alkyl groups may be substituted with carboxylate, hydroxyl, sulfonyl, or sulfonate groups; n is an integer from 2 to 5 (inclusive); R 2 It is C5-C 12 Alkyl; R 3 It is C3-C 10 Alkyl; terminal nitrogen optionally further converted to R 4 Replace, where R 4 The compound is selected from hydrogen, oxygen atoms and C1-C6 alkyl groups, wherein the C1-C6 alkyl groups may be substituted with carboxylate, hydroxyl, sulfonyl or sulfonate groups; and optionally, counterions may associate with the compound, and if present, counterions may be selected from chloride, bromide, iodide and 4-methylbenzenesulfonate groups.

[0009] This disclosure further provides compounds of formula II, which are also referred to herein as surfactants: Where R 1 Selected from hydrogen, oxygen atoms, and C1-C6 alkyl groups, wherein the C1-C6 alkyl groups may be substituted with carboxylate, hydroxyl, sulfonyl, or sulfonate groups; n is an integer from 2 to 5 (inclusive); R 2It is C5-C 12 Alkyl; R 3 It is C3-C 10 Alkyl; terminal nitrogen optionally further converted to R 4 Replace, where R 4 The compound is selected from hydrogen, oxygen atoms and C1-C6 alkyl groups, wherein the C1-C6 alkyl groups may be substituted with carboxylate, hydroxyl, sulfonyl or sulfonate groups; and optionally, counterions may associate with the compound, and if present, counterions may be selected from chloride, bromide and iodide ions.

[0010] One specific compound disclosed herein is 6-((2-butyloctyl)oxy)-N,N,N-trimethyl-6-oxohexane-1-amineon iodide, having the following formula: .

[0011] The second specific compound provided in this disclosure is 6-((2-butyloctyl)oxy)-N,N-dimethyl-6-oxohexane-1-aminoonium-4-methylbenzenesulfonate, which has the following formula: .

[0012] The third specific compound disclosed herein is 6-((2-butyloctyl)oxy)-N,N-dimethyl-6-oxohexane-1-amineonium chloride, having the following formula: .

[0013] The fourth specific compound disclosed herein is 4-((6-((2-butyloctyl)oxy)-6-oxohexyl)dimethylammonium)butane-1-sulfonate, having the following formula: .

[0014] The fifth specific compound disclosed herein is 6-(dimethylamino)hexanoate-2-butyloctyl ester N-oxide, which has the following formula: .

[0015] The sixth specific compound disclosed herein is 6-((2-butyloctyl)oxy)-6-oxohexane-1-amineonium chloride, which has the following formula: .

[0016] The above and other features of this disclosure, and the ways in which they are implemented, will become more apparent and will be better understood by referring to the following description of the embodiments in conjunction with the accompanying drawings. Attached Figure Description

[0017] Figure 1The graph shows the surface tension versus concentration measured at pH = 7 as described in Example 1B, where the Y-axis depicts the surface tension (γ) in millinewtons per meter (mN / m) and the X-axis depicts the concentration (c) in millimoles (mM).

[0018] Figure 2A The graph shows the surface tension versus concentration measured at pH = 7 as described in Example 2B, where the Y-axis depicts the surface tension (γ) in millinewtons per meter (mN / m) and the X-axis depicts the concentration (c) in millimoles (mM).

[0019] Figure 2B A graph showing the dynamic surface tension as a function of time, as described in Example 2C, is displayed, where the Y-axis depicts the surface tension in millinewtons per meter (mN / m) and the X-axis depicts the surface age in milliseconds (ms).

[0020] Figure 3 The graph shows the surface tension versus concentration measured at pH = 7 as described in Example 3B, where the Y-axis depicts the surface tension (γ) in millinewtons per meter (mN / m) and the X-axis depicts the concentration (c) in millimoles (mM).

[0021] Figure 4A The graph shows the surface tension versus concentration measured at pH = 7 as described in Example 4B, where the Y-axis depicts the surface tension (γ) in millinewtons per meter (mN / m) and the X-axis depicts the concentration (c) in millimoles (mM).

[0022] Figure 4B A graph showing the dynamic surface tension as a function of time, as described in Example 4C, is displayed, where the Y-axis depicts the surface tension in millinewtons per meter (mN / m) and the X-axis depicts the surface lifetime in milliseconds (ms).

[0023] Figure 5A The graph shows the surface tension versus concentration measured at pH = 7 as described in Example 5B, where the Y-axis depicts the surface tension (γ) in millinewtons per meter (mN / m) and the X-axis depicts the concentration (c) in millimoles (mM).

[0024] Figure 5B A graph showing the dynamic surface tension as a function of time, as described in Example 5C, is displayed, where the Y-axis depicts the surface tension in millinewtons per meter (mN / m) and the X-axis depicts the surface lifetime in milliseconds (ms).

[0025] Figure 6A The graph shows the surface tension versus concentration measured at pH = 7 as described in Example 6B, where the Y-axis depicts the surface tension (γ) in millinewtons per meter (mN / m) and the X-axis depicts the concentration (c) in millimoles (mM).

[0026] Figure 6B A graph showing the dynamic surface tension as a function of time, as described in Example 6C, is displayed, where the Y-axis depicts the surface tension in millinewtons per meter (mN / m) and the X-axis depicts the surface lifetime in milliseconds (ms). Detailed Implementation

[0027] I. Definition The phrase “any range between any two of the preceding values” as used in this article literally means any range that can be selected from any two values ​​listed before this phrase, regardless of whether those values ​​are in the lower or higher part of the list. For example, a pair of values ​​can be selected from two lower values, two higher values, or one lower value and one higher value.

[0028] The term "alkyl" as used in this article refers to any saturated carbon chain, which can be straight or branched.

[0029] The phrase “surfactant” as used herein refers to the ability of a compound to reduce the surface tension of the medium in which it is dissolved and / or the interfacial tension with other phases, and thus to adsorb at liquid / vapor and / or other interfaces. The term “surfactant” can be applied to such compounds.

[0030] Regarding imprecise terminology, the terms "approximately" and "roughly" are used interchangeably to refer to a measurement that includes the stated measurement and any measurement that is reasonably close to it. As understood and readily determined by one of ordinary skill in the art, a measurement that is reasonably close to the stated measurement deviates from it by a reasonably small amount. For example, such deviations may be attributable to measurement errors or minor adjustments made to optimize performance. In cases where the value of such a reasonably small difference is not readily determined by one of ordinary skill in the art, the terms "approximately" and "roughly" may be understood to mean the value plus or minus 10%.

[0031] II. Surfactant molecular formula This disclosure provides derivatives of amino acids having branched alkyl structures. The amino acids may be naturally occurring or synthetic, or they may be obtained from ring-opening reactions of lactams (such as caprolactam). The compounds of this disclosure have shown to possess surface-active properties and can be used, for example, as surfactants and wetting agents. In particular, this disclosure provides compounds of formula I shown below: Where R 1 Selected from hydrogen, oxygen atoms, and C1-C6 alkyl groups, wherein the C1-C6 alkyl groups may be substituted with carboxylate, hydroxyl, sulfonyl, or sulfonate groups; n is an integer from 2 to 5 (inclusive); R 2 It is C5-C 12 Alkyl; R 3 It is C3-C 10 Alkyl; terminal nitrogen optionally further converted to R 4 Replace, where R 4 The compound is selected from hydrogen, oxygen atoms and C1-C6 alkyl groups, wherein the C1-C6 alkyl groups may be substituted with carboxylate, hydroxyl, sulfonyl or sulfonate groups; and optionally, counterions may associate with the compound, and if present, counterions may be selected from chloride, bromide, iodide and 4-methylbenzenesulfonate groups.

[0032] This disclosure further provides compounds of formula II, which are also referred to herein as surfactants: Where R 1 Selected from hydrogen, oxygen atoms, and C1-C6 alkyl groups, wherein the C1-C6 alkyl groups may be substituted with carboxylate, hydroxyl, sulfonyl, or sulfonate groups; n is an integer from 2 to 5 (inclusive); R 2 It is C5-C 12 Alkyl; R 3 It is C3-C 10 Alkyl; terminal nitrogen optionally further converted to R 4 Replace, where R 4 The compound is selected from hydrogen, oxygen atoms and C1-C6 alkyl groups, wherein the C1-C6 alkyl groups may be substituted with carboxylate, hydroxyl, sulfonyl or sulfonate groups; and optionally, counterions may associate with the compound, and if present, counterions may be selected from chloride, bromide and iodide ions.

[0033] One specific compound disclosed herein is 6-((2-butyloctyl)oxy)-N,N,N-trimethyl-6-oxohexane-1-amineon iodide, having the following formula: .

[0034] The second specific compound provided in this disclosure is 6-((2-butyloctyl)oxy)-N,N-dimethyl-6-oxohexane-1-aminoonium-4-methylbenzenesulfonate, which has the following formula: .

[0035] The third specific compound disclosed herein is 6-((2-butyloctyl)oxy)-N,N-dimethyl-6-oxohexane-1-amineonium chloride, having the following formula: .

[0036] The fourth specific compound disclosed herein is 4-((6-((2-butyloctyl)oxy)-6-oxohexyl)dimethylammonium)butane-1-sulfonate, having the following formula: .

[0037] The fifth specific compound disclosed herein is 6-(dimethylamino)hexanoate-2-butyloctyl ester N-oxide, which has the following formula: .

[0038] In the above structure, the symbol "N→O" is intended to express the nonionic bonding interaction between nitrogen and oxygen.

[0039] The sixth specific compound disclosed herein is 6-((2-butyloctyl)oxy)-6-oxohexane-1-amineonium chloride, which has the following formula: .

[0040] III. Synthesis This surfactant compound can be synthesized by various methods. One such method involves opening a lactam (which may be an N-alkylated lactam) to produce an amino acid having an N-terminus and a C-terminus. The C-terminus can then be reacted with an alcohol under acidic conditions to provide an amino acid ester. The N-terminus of the amino acid can be reacted with an alkylating agent to produce a quaternary ammonium salt, or the N-terminus of the amino acid ester can be reacted with an acid to produce a quaternary ammonium salt.

[0041] Alternatively, the method may include opening a lactam to produce an amino acid having an N-terminus and a C-terminus. The N-terminus may then react with an alkylating agent to produce a tertiary amine. The C-terminus may then react with an alcohol under acidic conditions to provide an amino acid ester. The N-terminus of the amino acid may react with an alkylating agent to produce a quaternary ammonium salt, or the N-terminus of the amino acid ester may react with an acid to produce a quaternary ammonium salt.

[0042] Amino acids can be naturally occurring or synthetic, or they can be derived from ring-opening reactions of lactams (such as propiolactam, butyrolactam, valproic acid, and caprolactam). Ring-opening reactions can be acid- or base-catalyzed, and an example of an acid-catalyzed reaction involving caprolactam is shown in Scheme 1 below.

[0043] Option 1 Amino acids may have as few as two or as many as five carbons between their N-terminus and 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 by one or more substituents selected from hydroxyl, amino, amide, sulfonyl, sulfonate, carboxyl, and carboxylate groups. The N-terminal nitrogen may be acylated or alkylated by one or more alkyl groups. For example, an amino acid may be 6-(dimethylamino)hexanoic acid.

[0044] The amino acid can be further described in detail as shown in Scheme 2 below, wherein R, R', and R" can be hydrogen or C1-C6 alkyl, R 2 It can be C5-C 12 Alkyl, and R 3 It can be C3-C 10 Alkyl groups. For example, amino acids can undergo esterification, in which the amino acid is treated with an alcohol under acidic conditions to provide an amino acid ester.

[0045] Option 2 As shown in Scheme 3 below, the resulting amino acid ester can be subsequently alkylated or protonated to obtain an ammonium salt. Alkylation can be accomplished by treatment with an alkylating agent (such as iodomethane) in the presence of a base (such as sodium carbonate) to provide a quaternary ammonium salt, the counterion of which is determined by the alkylating agent used. For example, treatment with iodomethane provides a quaternary ammonium iodide salt. Protonation can be accomplished by treating the amino acid ester with an acid (such as hydrochloric acid). The identity of the acid determines the counterion present in the salt. For example, treatment with hydrochloric acid produces an ammonium chloride salt.

[0046] Option 3 IV. Properties of surfactants.

[0047] The compounds disclosed herein exhibit surface-active properties. These properties can be measured and described by various methods. One way to describe surfactants is by the critical micelle concentration (CMC) of the molecule. The CMC can be defined as the concentration of the surfactant at which micelles form, and above this concentration, all other surfactants are incorporated into the micelles.

[0048] As surfactant concentration increases, surface tension decreases. Once the surface is completely covered by surfactant molecules, micelles begin to form. This point represents the center of gravity (CMC) and the minimum surface tension. Further addition of surfactant will not further affect the surface tension. Therefore, the CMC can 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. The Wilhelmy plate is typically a thin iridium-platinum plate, which is attached to a balance by a wire and placed perpendicular to the air-liquid interface. The balance is used to measure the force applied to the plate by wetting. The surface tension (γ) is then calculated using this value according to Equation 1: Equation 1: γ = F / l cosθ Where l equals the wetted perimeter (2w + 2d, where w and d are the thickness and width of the plate, respectively), and cosθ is the contact angle between the liquid and the plate, which is assumed to be 0 in the absence of existing literature values.

[0049] Another parameter used to evaluate surfactant performance is dynamic surface tension. Dynamic surface tension is the surface tension value over a specific surface or interface lifetime. In the case of liquids with added surfactants, this can differ from the equilibrium value. Immediately after surface formation, the surface tension is equal to that of the pure liquid. As mentioned above, surfactants reduce surface tension; therefore, the surface tension decreases until an equilibrium value is reached. The time required to reach equilibrium depends on the surfactant's diffusion and adsorption rates.

[0050] One method for measuring dynamic surface tension relies on a bubble pressure tensiometer. This device measures the maximum internal pressure of a bubble forming in a liquid via a capillary. The measured value corresponds to the surface tension at a given surface lifetime (the time from the start of bubble formation to the attainment of the maximum pressure). The dependence of surface tension on surface lifetime can be measured by varying the rate of bubble formation.

[0051] Surfactant compounds can also be evaluated by their wetting ability on solid substrates (e.g., measured by contact angle). When a droplet comes into contact with a solid surface in a third medium (such as air), a three-phase line is formed between the liquid, gas, and solid. The angle between the unit vector of surface tension acting on the three-phase line and tangent to the droplet and the surface is described as the contact angle. The contact angle (also known as the wetting angle) is a measure of the wettability of a liquid on a solid. In the case of complete wetting, the liquid spreads completely over the solid, and the contact angle is 0°. The wetting properties of a given compound are typically measured at concentrations of 1–10 × CMC; however, it is not a concentration-dependent property, and therefore, wetting properties can be measured at higher or lower concentrations.

[0052] In one method, an optical contact angle goniometer can be used to measure the contact angle. This device uses a digital camera and software to obtain the contact angle by analyzing the profile shape of a droplet attached to a surface.

[0053] Potential applications of the surfactant compounds disclosed herein include formulations for use in shampoos, conditioners, detergents, spot-free rinses, floor and carpet cleaners, graffiti removers, wetting agents for crop protection, adjuvants for crop protection, and wetting agents for aerosol spraying.

[0054] Those skilled in the art will understand that small differences between compounds can lead to significantly different surfactant properties, allowing different compounds to be used with different substrates in different applications. For example, small variations in the hydrophobic portion of a surfactant, such as differences in the number of carbons in the alkyl chain, the presence of branched alkyl chains, the number of branches in the branched alkyl chains, and the number of carbons in each branch of the branched alkyl chains, can result in different surfactant properties. Similarly, in the case of cationic and anionic surfactants, different counterions can significantly alter the surfactant properties of the compound.

[0055] The compound is effective as a surfactant, especially as a wetting or foaming agent, dispersant, emulsifier and detergent.

[0056] The amount of the compounds disclosed herein used in the formulation may be as low as about 0.001 wt%, about 0.05 wt%, about 0.1 wt%, about 0.5 wt%, about 1 wt%, about 2 wt%, or about 5 wt%, or as high as about 8 wt%, about 10 wt%, about 15 wt%, about 20 wt%, or about 25 wt%, or any range defined between any two of the foregoing values.

[0057] The following non-limiting examples are provided to illustrate the different properties of different surfactants. Example

[0058] Nuclear magnetic resonance (NMR) spectroscopy was performed on a Bruker 500 MHz spectrometer. The critical micelle concentration (CMC) was determined at 23 °C using a tensiometer (DCAT 11, DataPhysics Instruments GmbH) equipped with a Pt-Ir plate via the Wilhelmy pendant method. Dynamic surface tension was determined at 23 °C using a bubble pressure tensiometer (Krüss BP100, Krüss GmbH). The contact angle was determined using an optical contact angle goniometer (OCA 15 Pro, DataPhysics GmbH) equipped with a digital camera.

[0059] Example 1a: Synthesis of 6-((2-Butyloctyl)oxy)-N,N,N-trimethyl-6-oxohexane-1-amineonium 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. Iodomethane (6.12 mmol, 0.38 mL) was added, and the mixture was heated to 40 °C for 24 h, followed by cooling to room temperature. The mixture was filtered, and the solvent was removed under vacuum to give 6-((2-butyloctyl)oxy)-N,N,N-trimethyl-6-oxohexane-1-amineonium iodide as a yellow solid in 90% yield. 1 H NMR (500 MHz, DMSO) δ 3.93 (d, J = 5.7 Hz, 2H), 3.29 – 3.22 (m, 2H), 3.04 (s, 9H), 2.34 (t, J = 7.4 Hz, 2H), 1.73 – 1.53(m, 5H), 1.33-1.25 (m, 18H), 0.88-0.85 (m, 6H).

[0060] Example 1b: Determining the critical micelle concentration (CMC) The critical micelle concentration (CMC) of 6-((2-butyloctyl)oxy)-N,N,N-trimethyl-6-oxohexane-1-amineonium iodide from Example 1a was tested. Figure 1 As shown in the graph, the CMC value cannot be clearly determined at concentrations up to 10 mg / mL, where the surface tension asymptotically approaches a value of approximately 27 mN / m. Figure 1 These are graphs of the results, showing the effect of surface tension on concentration. From the graphs, the surface tension at CMC is equal to or less than approximately 27 mN / m.

[0061] Example 2a: Synthesis of 6-((2-Butyloctyl)oxy)-N,N-dimethyl-6-oxohexane-1-aminoonium 4-methylbenzenesulfonate 6-(dimethylamino)hexanoic acid was treated in benzene at 120 °C with 2-butyloctyl-1-ol and p-toluenesulfonic acid for 12 hours. 6-((2-butyloctyl)oxy)-N,N-dimethyl-6-oxohexane-1-aminoonium 4-methylbenzenesulfonate was isolated as a white waxy solid and recrystallized from acetone in 49% yield. 1H NMR (500 MHz, DMSO) δ 7.48 (dd, J= 8.4, 0.6 Hz, 2H), 7.12 (dd, J = 8.4, 0.6 Hz, 1H), 3.93 (d, J = 5.7 Hz, 2H), 3.02 – 3.00 (m, 2H), 2.76 (d, J = 5.0 Hz, 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, 2.7 Hz, 6H).

[0062] Example 2b: Determining the critical micelle concentration (CMC) The critical micelle concentration (CMC) of 6-((2-butyloctyl)oxy)-N,N-dimethyl-6-oxohexane-1-aminoonium 4-methylbenzenesulfonate from Example 2a was tested. Based on the change in surface tension with concentration in water, the CMC was determined to be approximately 0.97 mmol. The minimum surface tension plateau value achievable by this surfactant is approximately 27 mN / m, i.e., 27 mN / m ± 3 mN / m. Figure 2A These are graphs of the results, showing the effect of surface tension on concentration. From the graphs, the surface tension at CMC is equal to or less than approximately 30 mN / m.

[0063] Example 2c: Determine dynamic surface tension The dynamic surface tension of 6-((2-butyloctyl)oxy)-N,N-dimethyl-6-oxohexane-1-aminoonium 4-methylbenzenesulfonate from Example 2a was determined using a bubble pressure tensiometer that measures the change in surface tension at the newly formed air-water interface over time. Figure 2B A graph of surface tension versus time is shown, indicating that the surface tension decreases rapidly from approximately 46 mN / m to approximately 30 mN / m in the time interval from 10 ms to 100 ms. In the time interval from 100 ms to 8,000 ms, the surface tension decreases slowly from 30 mN / m to approximately 27 mN / m, asymptotically approaching the saturation value of surface tension at the CMC.

[0064] Example 2d: Determine wetting properties In addition to surface tension and surface dynamics, the wetting properties of 6-((2-butyloctyl)oxy)-N,N-dimethyl-6-oxohexane-1-aminoonium 4-methylbenzenesulfonate from Example 2a were tested on various surfaces. For example, hydrophobic substrates (such as polyethylene-HD) exhibited surface wetting with a contact angle of 24.3°. On oleophobic and hydrophobic substrates (such as Teflon), the measured contact angle was much smaller than the water contact angle of 119°, at 48.2° (Table 1).

[0065] Table 1 substrate CA of the surfactant o ) concentration CA of water o )]> Teflon 48.2 10×CMC 119 Polyethylene-HD 24.3 10×CMC 93.6 Nylon 13.5 10×CMC 50 Polyethylene terephthalate 7.7 10×CMC 65.3 Example 3a: Synthesis of 6-((2-Butyloctyl)oxy)-N,N-dimethyl-6-oxohexane-1-amineonium chloride Treat 2-butyloctyl 6-(dimethylamino)hexanoate with one equivalent of hydrochloric acid to provide 6-((2-butyloctyl)oxy)-N,N-dimethyl-6-oxohexane-1-amineonium chloride.

[0066] Example 3b: Determining the critical micelle concentration (CMC) The critical micelle concentration (CMC) of 6-((2-butyloctyl)oxy)-N,N-dimethyl-6-oxohexane-1-amineonium chloride from Example 3a was tested. Based on the change in surface tension with concentration in water, the CMC was determined to be approximately 27.47 mmol. The minimum achievable surface tension of this surfactant is approximately 29 mN / m, i.e., 29 mN / m ± 3 mN / m. Figure 3 The graph shows the surface tension versus concentration. From the graph, the CMC value cannot be clearly determined at concentrations up to 27.4 mmol, where the surface tension asymptotically approaches a value of approximately 29 mN / m.

[0067] Example 4a: Synthesis of 4-((6-((2-Butyloctyl)oxy)-6-oxohexyl)dimethylammonium)butane-1-sulfonate 2.04 mmol (700 mg) of 6-(dimethylamino)hexanoate-2-butyloctyl ester was dissolved in ethyl acetate (30 mL). 1,4-Butanesulfonyl lactone (3.06 mmol, 0.31 mL) was added. The mixture was heated to reflux for 12 hours, followed by solvent evaporation. The resulting white waxy solid was washed with acetone to give 4-((6-((2-butyloctyl)oxy)-6-oxohexyl)dimethylammonium)butane-1-sulfonate in 89% yield. 1H NMR (500 MHz, DMSO) δ 3.93 (d, J =5.7 Hz, 2H), 3.30-3.28 (m, 4H), 2.97 (s, 3H), 2.49 – 2.43 (m, 2H), 2.34 (t, J= 7.4 Hz, 2H), 1.96– 1.76 (m, 9H), 1.27-1.25 (m, 18H), 0.88 – 0.85 (m, 6H).

[0068] Example 4b: Determining the critical micelle concentration (CMC) The critical micelle concentration (CMC) of 4-((6-((2-butyloctyl)oxy)-6-oxohexyl)dimethylammonium)butane-1-sulfonate from Example 4a was tested. Based on the change in surface tension with concentration in water, the CMC was determined to be approximately 0.54 mmol. The minimum surface tension plateau value achievable by this surfactant is approximately 32 mN / m, i.e., 32 mN / m ± 3 mN / m. Figure 4A These are graphs of the results, showing the effect of surface tension on concentration. From the graphs, the surface tension at CMC is equal to or less than approximately 32 mN / m.

[0069] Example 4c: Determine dynamic surface tension The dynamic surface tension of 4-((6-((2-Butyloctyl)oxy)-6-oxohexyl)dimethylammonium)butane-1-sulfonate from Example 4a was determined using a bubble pressure tensiometer that measures the change in surface tension at the newly formed air-water interface over time. Figure 4B A graph of surface tension versus time is shown, indicating that the surface tension decreases rapidly from approximately 66 mN / m to approximately 36 mN / m in the time interval from 10 ms to 100 ms. In the time interval from 100 ms to 8,000 ms, the surface tension decreases slowly from 36 mN / m to approximately 32 mN / m, asymptotically approaching the saturation value of surface tension at the CMC.

[0070] Example 4d: Determine wetting properties In addition to surface tension and surface dynamics, the wetting properties of 4-((6-(((2-butyloctyl)oxy)-6-oxohexyl)dimethylammonium)butane-1-sulfonate from Example 4a were tested on various surfaces. For example, hydrophobic substrates (such as polyethylene-HD) exhibited surface wetting with a contact angle of 44.4°. On oleophobic and hydrophobic substrates (such as Teflon), the measured contact angle was much smaller than the water contact angle of 119°, at 62.2° (Table 2).

[0071] Table 2 substrate <![CDATA[CA of surfactant ( o )]]> concentration <![CDATA[CA of water ( o )]]> Teflon 62.2 10×CMC 119 Polyethylene-HD 44.4 10×CMC 93.6 nylon 28.7 10×CMC 50 Polyethylene terephthalate 29.8 10×CMC 65.3 Example 5a: Synthesis of 2-butyloctyl 6-(dimethylamino)hexanoate N-oxide 6-(dimethylamino)hexanoate-2-butyloctyl ester was treated with hydrogen peroxide in water at 70°C for 24 hours to obtain 6-(dimethylamino)hexanoate-2-butyloctyl ester N-oxide as an oil, with a yield of 90%. 1 H NMR (500 MHz, DMSO) δ 3.93 (d, J = 5.7 Hz, 2H), 3.30-3.28 (m, 4H), 2.97 (s, 3H), 2.49 –2.43 (m, 2H), 2.34 (t, J = 7.4 Hz, 2H), 1.96– 1.76 (m, 9H), 1.27-1.25 (m,18H), 0.88 – 0.85 (m, 6H).

[0072] Example 5b: Determining the critical micelle concentration (CMC) The critical micelle concentration (CMC) of 6-(dimethylamino)hexanoate-2-butyloctyl ester N-oxide from Example 5a was tested. Based on the change in surface tension with concentration in water, the CMC was determined to be approximately 0.29 mmol. The minimum surface tension plateau value achievable by this surfactant is approximately 28 mN / m, i.e., 28 mN / m ± 3 mN / m. Figure 5A These are graphs of the results, showing the effect of surface tension on concentration. From the graphs, the surface tension at CMC is equal to or less than approximately 28 mN / m.

[0073] Example 5c: Determine dynamic surface tension The dynamic surface tension of 6-(dimethylamino)hexanoate-2-butyloctyl ester N-oxide from Example 5a was determined using a bubble pressure tensiometer that measures the change in surface tension at the newly formed air-water interface over time. Figure 5BA graph of surface tension versus time is shown, indicating that the surface tension decreases rapidly from approximately 60 mN / m to approximately 30 mN / m in the time interval from 10 ms to 1,000 ms. In the time interval from 1,000 ms to 8,000 ms, the surface tension decreases slowly from 30 mN / m to approximately 28 mN / m, asymptotically approaching the saturation value of surface tension at the CMC.

[0074] Example 5d: Determine wetting properties In addition to surface tension and surface dynamics, the wetting properties of 6-(dimethylamino)hexanoate-2-butyloctyl ester N-oxide from Example 5a were tested on various surfaces. For example, hydrophobic substrates (such as polyethylene-HD) exhibited surface wetting with a contact angle of 31.6°. On oleophobic and hydrophobic substrates (such as Teflon), the measured contact angle was much smaller than the water contact angle of 119°, at 41.5° (Table 3).

[0075] Table 3 substrate <![CDATA[CA of surfactant ( o )]]> concentration <![CDATA[CA of water ( o )]]> Teflon 41.0 10×CMC 119 Polyethylene-HD 31.9 10×CMC 93.6 nylon 38.5 10×CMC 50 Polyethylene terephthalate 9.2 10×CMC 65.3 Example 6a: Synthesis of 6-((2-Butyloctyl)oxy)-6-oxohexane-1-amineonium chloride 6-(dimethylamino)hexanoic acid-2-butyloctyl ester was treated with 1 equivalent of hydrochloric acid.

[0076] Example 6b: Determining the critical micelle concentration (CMC) The critical micelle concentration (CMC) of 6-((2-butyloctyl)oxy)-6-oxohexane-1-amineonium chloride from Example 6a was tested. Based on the change in surface tension with concentration in water, the CMC was determined to be approximately 0.15 mmol. The minimum surface tension plateau value achievable by this surfactant is approximately 27 mN / m, i.e., 27 mN / m ± 3 mN / m. Figure 6A These are graphs of the results, showing the effect of surface tension on concentration. From the graphs, the surface tension at CMC is equal to or less than approximately 30 mN / m.

[0077] Example 6c: Determine dynamic surface tension The dynamic surface tension of 6-((2-butyloctyl)oxy)-6-oxohexane-1-amineonium chloride from Example 6a was determined using a bubble pressure tensiometer that measures the change in surface tension at the newly formed air-water interface over time. Figure 6BA graph of surface tension versus time is shown, showing that the surface tension slowly decreases from about 69 mN / m to about 29 mN / m in the time interval from 10 ms to 8,000 ms, with a slight plateau of about 49 mN / m at the surface lifetime of 1,000 ms, close to the saturation value of surface tension at CMC.

[0078] Example 6d: Determine wetting properties In addition to surface tension and surface dynamics, the wetting properties of the 6-((2-butyloctyl)oxy)-6-oxohexane-1-amineonium chloride from Example 6a were tested on various surfaces. For example, hydrophobic substrates (such as polyethylene-HD) exhibited surface wetting with a contact angle of 25.8°. On oleophobic and hydrophobic substrates (such as Teflon), the measured contact angle was much smaller than the water contact angle of 119°, at 48.7° (Table 4).

[0079] Table 4 substrate <![CDATA[CA of surfactant ( o )]]> concentration <![CDATA[CA of water ( o )]]> Teflon 48.7 10×CMC 119 Polyethylene-HD 25.8 10×CMC 93.6 nylon 24.5 10×CMC 50 Polyethylene terephthalate 20.1 10×CMC 65.3 aspect Aspect 1 is a compound with the following formula: Where R 1 Selected from hydrogen, oxygen atoms, and C1-C6 alkyl groups, wherein the C1-C6 alkyl groups may be substituted with carboxylate, hydroxyl, sulfonyl, or sulfonate groups; n is an integer from 2 to 5 (inclusive); R 2 It is C5-C 12 Alkyl; R 3 It is C3-C 10 Alkyl; terminal nitrogen optionally further converted to R 4 Replace, where R 4 The compound is selected from hydrogen, oxygen atoms and C1-C6 alkyl groups, wherein the C1-C6 alkyl groups may be substituted with carboxylate, hydroxyl, sulfonyl or sulfonate groups; and optionally, counterions may associate with the compound, and if present, counterions may be selected from chloride, bromide, iodide and 4-methylbenzenesulfonate groups.

[0080] Aspect 2 is a compound of aspect 1, wherein the compound is 6-((2-butyloctyl)oxy)-N,N,N-trimethyl-6-oxohexane-1-amineonium iodide, having the following formula: .

[0081] Aspect 3 is the compound of aspect 2, which has a critical micelle concentration (CMC) of approximately 21.30 mmol in water.

[0082] Aspect 4 is a compound of aspect 1, wherein the compound is 6-((2-butyloctyl)oxy)-N,N-dimethyl-6-oxohexane-1-aminoonium 4-methylbenzenesulfonate, which has the following formula: .

[0083] Aspect 5 is the compound of aspect 4, which has a critical micelle concentration (CMC) of approximately 0.97 mmol in water.

[0084] Aspect 6 is a compound of aspect 4 or aspect 5 that has a surface tension in water equal to or less than 30 mN / m at a surface lifetime of 100 ms or greater.

[0085] Aspect 7 is a compound of aspect 1, wherein the compound is 6-((2-butyloctyl)oxy)-N,N-dimethyl-6-oxohexane-1-amineonium chloride, having the following formula: .

[0086] Aspect 8 is a compound of aspect 7, which has a critical micelle concentration (CMC) of approximately 27.47 mmol in water.

[0087] Aspect 9 is a compound of aspect 1, wherein the compound is 4-((6-((2-butyloctyl)oxy)-6-oxohexyl)dimethylammonium)butane-1-sulfonate, having the following formula: .

[0088] Aspect 10 is a compound of aspect 9, which has a critical micelle concentration (CMC) of approximately 0.54 mmol in water.

[0089] Aspect 11 is a compound of aspect 9 or aspect 10, having a surface tension in water equal to or less than 36 mN / m at a surface lifetime of 100 ms or greater.

[0090] Aspect 12 is a compound of aspect 1, wherein the compound is 6-(dimethylamino)hexanoic acid-2-butyloctyl ester N-oxide, which has the following formula: .

[0091] Aspect 13 is a compound of aspect 12, which has a critical micelle concentration (CMC) of approximately 0.29 mmol in water.

[0092] Aspect 14 is a compound of aspect 12 or aspect 13 that has a surface tension in water equal to or less than 30 mN / m at a surface lifetime of 1,000 ms or greater.

[0093] Aspect 15 is a compound of the following formula: Where R 1 Selected from hydrogen, oxygen atoms, and C1-C6 alkyl groups, wherein the C1-C6 alkyl groups may be substituted with carboxylate, hydroxyl, sulfonyl, or sulfonate groups; n is an integer from 2 to 5 (inclusive); R 2 It is C5-C 12 Alkyl; R 3 It is C3-C 10 Alkyl; terminal nitrogen optionally further converted to R 4 Replace, where R 4 The compound is selected from hydrogen, oxygen atoms and C1-C6 alkyl groups, wherein the C1-C6 alkyl groups may be substituted with carboxylate, hydroxyl, sulfonyl or sulfonate groups; and optionally, counterions may associate with the compound, and if present, counterions may be selected from chloride, bromide and iodide ions.

[0094] Aspect 16 is a compound of aspect 15, wherein the compound is 6-((2-butyloctyl)oxy)-6-oxohexane-1-amineonium chloride, having the following formula: .

[0095] Aspect 17 is a compound of aspect 16, which has a critical micelle concentration (CMC) of approximately 0.15 mmol in water.

[0096] Aspect 18 is a compound of aspect 16 or aspect 17 that has a surface tension in water equal to or less than 49 mN / m at a surface lifetime of 1,000 ms or greater.

[0097] Aspect 19 is a liquid composition comprising: a medium; and a surfactant of the following formula: Where R 1 Selected from hydrogen, oxygen atoms, and C1-C6 alkyl groups, wherein the C1-C6 alkyl groups may be substituted with carboxylate, hydroxyl, sulfonyl, or sulfonate groups; n is an integer from 2 to 5 (inclusive); R 2 It is C5-C 12 Alkyl; R 3 It is C3-C 10 Alkyl; terminal nitrogen optionally further converted to R 4 Replace, where R 4 The compound is selected from hydrogen, oxygen atoms and C1-C6 alkyl groups, wherein the C1-C6 alkyl groups may be substituted with carboxylate, hydroxyl, sulfonyl or sulfonate groups; and optionally, counterions may associate with the compound, and if present, counterions may be selected from chloride, bromide, iodide and 4-methylbenzenesulfonate groups.

[0098] Aspect 20 is a composition of aspect 19, wherein the medium is water.

[0099] Aspect 21 is a liquid composition comprising: a medium; and a surfactant of the following formula: Where R 1 Selected from hydrogen, oxygen atoms, and C1-C6 alkyl groups, wherein the C1-C6 alkyl groups may be substituted with carboxylate, hydroxyl, sulfonyl, or sulfonate groups; n is an integer from 2 to 5 (inclusive); R 2 It is C5-C 12 Alkyl; R 3 It is C3-C 10 Alkyl; terminal nitrogen optionally further converted to R 4 Replace, where R 4 The compound is selected from hydrogen, oxygen atoms and C1-C6 alkyl groups, wherein the C1-C6 alkyl groups may be substituted with carboxylate, hydroxyl, sulfonyl or sulfonate groups; and optionally, counterions may associate with the compound, and if present, counterions may be selected from chloride, bromide and iodide ions.

[0100] Aspect 22 is a composition of aspect 21, wherein the medium is water.

Claims

1. The following compound: Where R 1 Selected from hydrogen, oxygen atoms and C1-C6 alkyl groups, wherein the C1-C6 alkyl group may be substituted with a carboxyl group, a hydroxyl group, a sulfonyl group or a sulfonate group; n is an integer from 2 to 5 (inclusive); R 2 It is C5-C 12 alkyl; R 3 It is C3-C 10 alkyl; The terminal nitrogen is optionally further converted to R 4 Replace, where R 4 Selected from hydrogen, oxygen atoms and C1-C6 alkyl groups, wherein the C1-C6 alkyl group may be substituted with a carboxyl group, a hydroxyl group, a sulfonyl group or a sulfonate group; Furthermore, the optional counter ion can associate with the compound, and if present, the counter ion can be selected from chloride ions, bromide ions, iodide ions, and 4-methylbenzenesulfonate ions.

2. The compound of claim 1, wherein the compound is 6-((2-butyloctyl)oxy)-N,N,N-trimethyl-6-oxohexane-1-amineonium iodide having the following formula: 。 3. The compound of claim 2, having a critical micelle concentration (CMC) of approximately 21.30 mmol in water.

4. The compound of claim 1, wherein the compound is 6-((2-butyloctyl)oxy)-N,N-dimethyl-6-oxohexane-1-aminoonium 4-methylbenzenesulfonate, having the following formula: 。 5. The compound of claim 4, having a critical micelle concentration (CMC) of about 0.97 mmol in water.

6. The compound of claim 4, having a surface tension in water equal to or less than 30 mN / m at a surface age of 100 ms or greater.

7. The compound of claim 1, wherein the compound is 6-((2-butyloctyl)oxy)-N,N-dimethyl-6-oxohexane-1-amineonium chloride, having the following formula: 。 8. The compound of claim 7, having a critical micelle concentration (CMC) of approximately 27.47 mmol in water.

9. The compound of claim 1, wherein the compound is 4-((6-((2-butyloctyl)oxy)-6-oxohexyl)dimethylammonium)butane-1-sulfonate, having the following formula: 。 10. The compound of claim 9, having a critical micelle concentration (CMC) of about 0.54 mmol in water.

11. The compound of claim 9, having a surface tension in water equal to or less than 36 mN / m at a surface lifetime of 100 ms or greater.

12. The compound of claim 1, wherein the compound is 6-(dimethylamino)hexanoate-2-butyloctyl ester N-oxide having the following formula: 。 13. The compound of claim 12, having a critical micelle concentration (CMC) of about 0.29 mmol in water.

14. The compound of claim 12, having a surface tension in water equal to or less than 30 mN / m at a surface lifetime of 1,000 ms or greater.

15. The following compounds: Where R 1 Selected from hydrogen, oxygen atoms and C1-C6 alkyl groups, wherein the C1-C6 alkyl group may be substituted with a carboxyl group, a hydroxyl group, a sulfonyl group or a sulfonate group; n is an integer from 2 to 5 (inclusive); R 2 It is C5-C 12 alkyl; R 3 It is C3-C 10 alkyl; The terminal nitrogen is optionally further converted to R 4 Replace, where R 4 Selected from hydrogen, oxygen atoms and C1-C6 alkyl groups, wherein the C1-C6 alkyl group may be substituted with a carboxyl group, a hydroxyl group, a sulfonyl group or a sulfonate group; Furthermore, the optional counter ion can associate with the compound, and if present, the counter ion can be selected from chloride ions, bromide ions, and iodide ions.

16. The compound of claim 15, wherein the compound is 6-((2-butyloctyl)oxy)-6-oxohexane-1-amineonium chloride having the following formula: 。 17. The compound of claim 16, having a critical micelle concentration (CMC) of about 0.15 mmol in water.

18. The compound of claim 16, having a surface tension in water equal to or less than 49 mN / m at a surface lifetime of 1,000 ms or greater.

19. A liquid composition comprising: medium; and The surfactant in the following formula: Where R 1 Selected from hydrogen, oxygen atoms and C1-C6 alkyl groups, wherein the C1-C6 alkyl group may be substituted with a carboxyl group, a hydroxyl group, a sulfonyl group or a sulfonate group; n is an integer from 2 to 5 (inclusive); R 2 It is C5-C 12 alkyl; R 3 It is C3-C 10 alkyl; The terminal nitrogen is optionally further converted to R 4 Replace, where R 4 Selected from hydrogen, oxygen atoms and C1-C6 alkyl groups, wherein the C1-C6 alkyl group may be substituted with a carboxyl group, a hydroxyl group, a sulfonyl group or a sulfonate group; Furthermore, the optional counter ion can associate with the compound, and if present, the counter ion can be selected from chloride ions, bromide ions, iodide ions, and 4-methylbenzenesulfonate ions.

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

21. A liquid composition comprising: medium; and The surfactant in the following formula: Where R 1 Selected from hydrogen, oxygen atoms and C1-C6 alkyl groups, wherein the C1-C6 alkyl group may be substituted with a carboxyl group, a hydroxyl group, a sulfonyl group or a sulfonate group; n is an integer from 2 to 5 (inclusive); R 2 It is C5-C 12 alkyl; R 3 It is C3-C 10 alkyl; The terminal nitrogen is optionally further converted to R 4 Replace, where R 4 Selected from hydrogen, oxygen atoms and C1-C6 alkyl groups, wherein the C1-C6 alkyl group may be substituted with a carboxyl group, a hydroxyl group, a sulfonyl group or a sulfonate group; Furthermore, the optional counter ion can associate with the compound, and if present, the counter ion can be selected from chloride ions, bromide ions, and iodide ions.

22. The composition of claim 21, wherein the medium is water.

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