N-acylamino alkane sulfonate surfactants and derivatives thereof

Abstract

A surfactant composition comprises greater than 75% by weight of an N-acylamino alkane sulfonate of formula (I). The surfactant composition is substantially free of solvent and NaCl. A process for preparing a mixture comprising an N-acylamino alkanesulfonate surfactant includes combining (a) an aminoalkanesulfonic acid of formula (II) or (b) an anhydrous alkali metal salt of an aminoalkanesulfonic acid of formula (II), an anhydrous base and a fatty alkyl ester of formula (III) to form a mixture comprising an N-acylamino alkanesulfonate of formula (I). The method further comprises increasing the temperature of the mixture to 190 DEG C or less, preferably 170 DEG C or less, more preferably 160 DEG C or less to form a reaction mixture; and continuously removing the alkyl alcohol from the reaction mixture. # imgabs0 #

Description

Technical Field

[0001] The present disclosure generally relates to N-acyl aminoalkane sulfonate surfactants and derivatives, and in certain embodiments, to N-acyl aminoalkane sulfonate surfactant compositions having low levels of impurities. Background Art

[0002] Surfactants are the most important cleaning ingredients in cleaning products. Environmental regulations, consumer habits, and consumer practices have forced the surfactant industry to make new developments to produce products that are lower in cost, higher in performance, and environmentally friendly.

[0003] Surfactants are key ingredients that play an important role in a variety of applications and consumer products, such as in detergents, hard surface cleaners, fabric softeners, body washes, facial cleansers, shampoo conditioners, conditioning shampoos, and other surfactant-based compositions. Many catalogs and patents describe surfactant selections that are too expensive to use. The cost is many times higher due to the starting materials used to prepare such surfactants, inefficient reaction schemes, and / or the complex methods required to manufacture the surfactant to meet specific quality attributes. Therefore, there is a need for new methods to produce surfactant compositions with minimal impurities or additives at low cost.

[0004] N-acyl taurates or N-acyl taurides (and other amino acid-based) surfactants, as named by others, can be commercially manufactured from the corresponding fatty acyl chlorides and amino acids using Schotten Baumann chemistry as shown in Formula 1.

[0005] Formula 1

[0006]

[0007] This amidation reaction is typically carried out in water, but the use of a mixed water-solvent system has been reported. Generally, the sodium N-acylaminoalkane sulfonate surfactant formed is obtained in the form of an aqueous composition containing 20% - 30% active substance and a constant high level of undesired inorganic salts (NaCl). The latter can be removed via an additional post-reaction step, which can significantly increase costs and process complexity. This surfactant preparation method is expensive and requires the use of chlorinating agents such as phosphorus trichloride (PCl3), phosphorus pentachloride (PCl5), thionyl chloride (SOCl2), oxalyl chloride (COCl2), or phosgene (a toxic gas) to produce fatty acyl chlorides. These chlorinating agents are highly reactive, may be toxic, and may require very special handling and metallurgy. Additionally, depending on the specific chemistry and method used, separating the fatty acyl chloride from by-products and the catalysts used is difficult to solve. As a result, the product may contain undesired impurities that can be carried over into the synthesis of the corresponding surfactant.

[0008] The preparation of N-acyl taurates by direct condensation of carboxylic acids with alkali metal salts of 2-aminoalkane sulfonic acids as shown in Formula 2 has also been reported. However, to carry out this reaction, water must be removed and high temperatures (190 °C - 240 °C) and an inert atmosphere are used. This direct amidation reaction can be carried out in the presence of catalysts such as zinc oxide, hypophosphorous acid, boric acid, etc., which will remain in the surfactant mixture. It is reported that decomposition by-products result in poor product yields and unacceptable product discoloration and odor. Generally, it is said that the carboxylic acid is used in a ≥30 molar excess relative to taurine. To produce N-acyl taurates free of fatty acids by this chemical route, the crude reaction mixture is subjected to additional purification treatment steps such as distillation, extraction, recrystallization, or combinations thereof.

[0009] Formula 2

[0010]

[0011] Fatty alkyl esters have also been used as starting materials. According to another method, fatty alkyl esters react with taurine in the presence of a polyol solvent such as glycerol or propylene glycol. The relative molar ratio of the polyol to the amino compound ranges from about 8:1 to about 1:1. In the main examples included, the resulting product contains 34% glycerol, which remains in the surfactant mixture and is undesirable for many applications.

[0012] In summary, N-acyl aminoalkane sulfonate surfactants prepared using these methods tend to contain high levels of undesirable by-products such as salts (NaCl), or solvents such as methanol, glycerol, and polypropylene glycol. Accordingly, there is a need for N-acyl aminoalkane sulfonate surfactant compositions prepared under atmospheric conditions that have a low proportion of by-products and low levels of solvents or additives. SUMMARY OF THE INVENTION

[0013] The present disclosure seeks to address one or more of these needs by providing a surfactant composition comprising greater than 75 wt% of an N-acyl aminoalkane sulfonate of formula (I), based on the weight of the surfactant composition:

[0014]

[0015] wherein R is a C5-C 21 alkyl substituent, R1 represents H or a C1 to C4 alkyl group, n is an integer from 1 to 2, and M is a cationic group selected from alkali metal salts and hydrogen, and the surfactant composition is substantially free of solvents and NaCl. The present disclosure also relates to surfactant compositions that are solid or aqueous liquid compositions.

[0016] The present disclosure also relates to a method for preparing a mixture comprising an N-acyl aminoalkane sulfonate surfactant, the method comprising combining: (a) an aminoalkane sulfonic acid of formula (II) or (b) an anhydrous alkali metal salt of an aminoalkane sulfonic acid of formula (II):

[0017]

[0018] wherein R1 represents H or a C1 to C4 alkyl group, n is an integer from 1 to 2, and M is a cationic group selected from alkali metal salts and hydrogen; an anhydrous base and a fatty alkyl ester of formula (III):

[0019]

[0020] wherein R is selected from C5-C 21 alkyl substituents, and R′ is a C1 or higher alkyl substituent, preferably methyl, to form a mixture comprising an N-acyl aminoalkane sulfonate of formula (I):

[0021]

[0022] wherein R is C5-C 21An alkyl substituent, R1 represents H or a C1 to C4 alkyl group, n is an integer from 1 to 2, and M is a cationic group selected from alkali metal salts and hydrogen; raising the temperature of the mixture to 190 °C or lower, preferably 170 °C or lower, more preferably 160 °C or lower, to form a reaction mixture; and continuously removing the alkyl alcohol from the reaction mixture.

[0023] In another aspect, the present disclosure relates to a consumer cleaning or personal care composition comprising from about 0.001 wt% to about 99.999 wt%, or from about 0.1 wt% to about 80 wt%, based on the total weight of the composition, of an N-acylaminoalkane sulfonate surfactant as described herein, and from 0.001 wt% to about 99.999 wt% of one or more additional cleaning components, or one or more additional personal care components. Detailed Description

[0024] The features and advantages of the present disclosure will become apparent from the following description, which includes examples intended to give a broad representation of the present disclosure. From this description and from the practice of the present disclosure, various modifications will be apparent to those skilled in the art. The scope is not intended to be limited to the specific forms disclosed, and the present disclosure encompasses all modifications, equivalents, and alternative alternatives that fall within the spirit and scope of the present disclosure as defined by the claims.

[0025] As used herein, when used in the claims or the specification, articles including "the", "a", and "an" are understood to refer to one or more of the substances claimed or described.

[0026] As used herein, the term "comprising" is intended to be non-limiting.

[0027] As used herein, the terms "substantially free of" or "substantially without" mean that the component is completely absent or present only in trace amounts as an impurity or an unintended byproduct of another component. A composition "substantially free of / without" a component means that the composition contains less than about 0.5%, 0.25%, 0.1%, 0.05% or 0.01%, or even 0%, by weight of the composition.

[0028] As used herein, the term "solid" includes particulate, powder, flake, noodle, needle, extrudate, ribbon, bead, and pellet product forms and contains less than about 0.5%, 0.25%, 0.1%, 0.05% or 0.01%, or even 0%, by weight of the composition of water.

[0029] As used herein, "personal cleansing compositions" include personal cleansing products such as shampoos, conditioners, conditioning shampoos, body gels, hand soaps, facial cleansers, and other surfactant-based liquid compositions.

[0030] It should be understood that every upper numerical limit given throughout this specification includes every lower numerical limit, as if such lower numerical limits were expressly written herein. Every lower numerical limit given throughout this specification will include every upper numerical limit, as if such upper numerical limits were expressly written herein. Every numerical range given throughout this specification will include every narrower numerical range that falls within such broader numerical range, as if such narrower numerical ranges were all expressly written herein.

[0031] In this specification, unless otherwise indicated, all concentrations are based on the weight of the composition.

[0032] The dimensions and values disclosed herein should not be construed as being strictly limited to the exact numerical values recited. Instead, unless otherwise indicated, each such dimension is intended to mean the recited value and a range functionally equivalent around that value. For example, a dimension disclosed as "40 mm" is intended to mean "about 40 mm".

[0033] N-acyl aminoalkane sulfonate surfactant

[0034] The N-acylaminoalkane sulfonate surfactants disclosed herein have the following general formula (I):

[0035]

[0036] wherein R is a C5-C 21 alkyl substituent, R1 represents H or a C1 to C4 alkyl group, n is an integer from 1 to 2, and M is a cationic group selected from alkali metal salts and hydrogen. Preferably, R is a C7-17 alkyl substituent. The alkyl substituent can be branched or unbranched.

[0037] The N-acylaminoalkane sulfonate surfactants described herein are generally not a single compound as shown in their general formula (I), but rather, as will be readily understood by those skilled in the art, the surfactant comprises a mixture of several homologues having different chain lengths and molecular weights. The N-acylaminoalkane sulfonate surfactants described herein can be saturated or unsaturated.

[0038] The N-acylaminoalkane sulfonate surfactant composition of the present disclosure comprises at least 50% by weight of an N-acylaminoalkane sulfonate surfactant based on the weight of the surfactant composition. For example, the composition may comprise 65% to 95%, 70% to 95%, 75% to 95%, 80% to 95%, 85% to 95%, 90% to 95%, 65% to 90%, 70% to 90%, 75% to 90%, 80% to 90%, 85% to 90%, 65% to 85%, 70% to 85%, 75% to 85%, 80% to 85%, 65% to 80%, 70% to 80%, 75% to 80%, 65% to 75%, 70% to 75%, or 65% to 70% by weight of an N-acylaminoalkane sulfonate surfactant based on the weight of the surfactant composition.

[0039] The surfactant composition may comprise at least 5% by weight, preferably from about 5% to about 15% by weight, more preferably from about 8% to about 10% by weight of an N-acyl-N-methylaminoalkane sulfonate surfactant. The surfactant composition may comprise 5% to 50%, 5% to 35%, 5% to 25%, 5% to 20%, 5% to 15%, 5% to 12%, 5% to 10%, 5% to 8%, 8% to 50%, 8% to 35%, 8% to 25%, 8% to 20%, 8% to 15%, 8% to 12%, 8% to 10%, 10% to 50%, 10% to 35%, 10% to 25%, 10% to 20%, 10% to 15%, 10% to 12%, 12% to 50%, 12% to 35%, 12% to 25%, 12% to 20%, 12% to 15%, 15% to 50%, 15% to 35%, 15% to 25%, 15% to 20%, 20% to 50%, 20% to 35%, or 25% to 50% by weight of an N-acyl-N-methylaminoalkane sulfonate surfactant.

[0040] The N-acylaminoalkane sulfonate surfactant composition of the present disclosure further comprises a fatty acid. The fatty acid may be present as a free fatty acid or in the form of a fatty acid soap. The amount in the composition may range from 1 wt% to about 10 wt%, 2 wt% to 7 wt%, or 3 wt% to 5 wt%, specifically listing all values within these ranges and any ranges resulting therefrom.

[0041] Advantageously, the N-acylaminoalkane sulfonate surfactant composition of the present disclosure may be substantially free of impurities, including water, salts (NaCl), polyol solvents, and methanol. The compositions of the present disclosure may contain less than 5%, 2%, 1%, 0.1%, substantially free of one or any combination of these impurities, and in some instances, free of one or any combination of these impurities.

[0042] The present disclosure also encompasses concentrated compositions, commonly referred to as pastes, and solids, such as powders and tablets. These concentrated compositions can be combined with various auxiliary ingredients (e.g., water) to prepare a variety of detergent products, including personal care compositions and laundry detergents.

[0043] Typically, an inorganic salt (NaCl) is added to a cleaning preparation made with a sulfated surfactant to thicken the product. Surprisingly, it has been found that in the presence of a cationic conditioning polymer, adding an inorganic salt to a preparation substantially free of sulfated surfactant and / or using a sulfate-free surfactant with a high content of inorganic salt may cause product instability due to the formation of a gel-like surfactant-polymer complex in the composition. Therefore, it is desirable to avoid or minimize the addition of NaCl to the preparation and / or use raw materials with a low content of inorganic salt (NaCl). Commercially available sulfate-free surfactants such as sodium methyl cocoyl taurate (cocoyl aminoalkane sulfonate) and other amino acid-based surfactants typically have a high level of inorganic salts, such as 5% or higher. Using these raw materials with a high content of salts (such as NaCl) in a cleaning preparation based on a sulfate-free surfactant can result in the formation of an undesirable gel-like surfactant-polymer complex in the product before use. The surfactant compositions described herein enable the formulation of stable cleaning products substantially free of sulfated surfactants.

[0044] Method for preparing N-acyl aminoalkane sulfonate surfactant

[0045] The methods described herein allow for the preparation of N-acylaminoalkanesulfonate surfactants with low levels of impurities. Conventional Schotten-Baumann acyl chloride routes to N-acylaminoalkanesulfonate surfactants produce NaCl and other impurities, resulting in an undesirable output. In addition, other reactions for preparing N-acylaminoalkanesulfonate surfactants use low-boiling solvents and are carried out under pressure in a closed reactor rather than under atmospheric conditions. High-pressure reaction conditions are inherently more dangerous, time-consuming, complex, and expensive and are thus not desirable. Others have used high-boiling solvents such as polyols, glycerol, and propylene glycol to carry out the reaction under atmospheric conditions, but the solvents that are difficult to remove remain with the surfactant.

[0046] Suitable methods for preparing the N-acylaminoalkanesulfonate surfactants disclosed herein include combining: (a) an aminoalkanesulfonic acid of formula (II) or (b) an anhydrous alkali metal salt of an aminoalkanesulfonic acid of formula (II):

[0047]

[0048] wherein R1 represents H or a C1 to C4 alkyl group, n is an integer from 1 to 2, and M is a cationic group selected from alkali metal salts and hydrogen; an anhydrous base and a fatty alkyl ester of formula (III):

[0049]

[0050] wherein R is selected from C5-C 21 alkyl substituents, and R′ is a C1 or higher alkyl substituent, preferably methyl, to form a mixture comprising an N-acylaminoalkanesulfonate of formula (I):

[0051]

[0052] wherein R is a C5-C 21 alkyl substituent, R1 represents H or a C1 to C4 alkyl group, n is an integer from 1 to 2, and M is a cationic group selected from alkali metal salts and hydrogen.

[0053] The method can prepare any of the surfactant compositions previously disclosed.

[0054] The reaction scheme for forming the surfactant composition is shown below:

[0055] Amidation reaction

[0056]

[0057] Unexpectedly, it has been found that when preparing sodium N-acyltaurinate surfactants by the following reaction:

[0058]

[0059] Sodium N-acyl-N-methyl taurate surfactant is also formed as part of the surfactant composition:

[0060]

[0061] It is expected that under the reaction conditions, at temperatures greater than 150 °C, the following side reaction occurs in situ to form sodium N-methyl taurate:

[0062]

[0063] It then reacts with the fatty alkyl ester to form the useful and valuable by-product sodium N-acyl-N-methyl taurate surfactant, as shown in the following reaction scheme:

[0064]

[0065] The combining step may include preparing a suspension of the aminoalkanesulfonate of formula (II) by adding the fatty alkyl ester of formula (III) to the anhydrous alkali metal salt of the aminoalkanesulfonic acid of formula (II), and contacting the suspension with the anhydrous base to form a mixture. It is desirable to add a solvent to the process because the amount of methanol supplied by the catalytic amount of anhydrous base, sodium methoxide solution, or generated by the amidation reaction is not sufficient to overcome the lack of miscibility / compatibility between the alkali metal salt of the aminoalkanesulfonic acid and the fatty alkyl ester. The solvent may be the same as or different from methanol, but preferably is the same as the solvent present in the anhydrous base and the same as the solvent formed in the amidation reaction. Additionally or alternatively, the combining step may include combining the anhydrous base and the fatty alkyl ester of formula (III) to form a premix, and then adding (a) the aminoalkanesulfonic acid of formula (II) or (b) the anhydrous alkali metal salt of the aminoalkanesulfonic acid of formula (II) to the premix to form a mixture. Additionally or alternatively, the combining step may include preparing a formulation of the aminoalkanesulfonate of formula (II) by adding the anhydrous base to the anhydrous alkali metal salt of the aminoalkanesulfonic acid of formula (II), and contacting the formulation with the fatty alkyl ester of formula (III) to form the mixture. Additionally or alternatively, the combining step may include preparing a formulation of the aminoalkanesulfonate of formula (II) by adding the anhydrous base to the aminoalkanesulfonic acid of formula (II), and contacting the formulation with the fatty alkyl ester of formula (III) to form the mixture.

[0066] Upon contact of the aminoalkanesulfonic acid only with the anhydrous base, a white, solid, agglomerate-like material may form. Thus, it is expected that a lower conversion and yield of the N-acylaminoalkanesulfonate surfactant can be achieved by first adding the aminoalkanesulfonic acid to the anhydrous base (sodium methoxide solution) and then adding the fatty alkyl ester. Thus, in this process, it is preferred to form the alkali metal salt of the aminoalkanesulfonic acid in situ by adding the aminoalkanesulfonic acid to a mixture consisting of the anhydrous base and the fatty alkyl ester. Additionally or alternatively, the process may include adding the anhydrous base to a suspension of the aminoalkanesulfonic acid in the fatty alkyl ester (FAME). Without being bound by theory, this is advantageous because the resulting alkali metal salt of the aminoalkanesulfonic acid formed is finely dispersed or soluble in the mixture containing the fatty alkyl ester.

[0067] The method may include adding an N-acyl aminoalkane sulfonate surfactant to water to form a surfactant composition that contains greater than 20% by weight, preferably greater than 25% by weight, and more preferably greater than 30% by weight of the N-acyl aminoalkane sulfonate surfactant, based on the weight of the surfactant composition. The method may include adding an N-acyl aminoalkane sulfonate surfactant to water to form a surfactant composition that includes from 20% to 95% by weight, 20% to 90% by weight, 20% to 85% by weight, 20% to 80% by weight, 20% to 75% by weight, 20% to 70% by weight, 20% to 65% by weight, 20% to 60% by weight, 20% to 55% by weight, 20% to 50% by weight, 25% to 95% by weight, 25% to 90% by weight, 25% to 85% by weight, 25% to 80% by weight, 25% to 75% by weight, 25% to 70% by weight, 25% to 65% by weight, 25% to 60% by weight, 25% to 55% by weight, 25% to 50% by weight, 30% to 95% by weight, 30% to 90% by weight, 30% to 85% by weight, 30% to 80% by weight, 30% to 75% by weight, 30% to 70% by weight, 30% to 65% by weight, 30% to 60% by weight, 30% to 55% by weight, 30% to 50% by weight, 40% to 95% by weight, 40% to 90% by weight, 40% to 85% by weight, 40% to 80% by weight, 40% to 75% by weight, 40% to 70% by weight, 40% to 65% by weight, 40% to 60% by weight, 40% to 55% by weight, 40% to 50% by weight, 50% to 95% by weight, 50% to 90% by weight, 50% to 85% by weight, 50% to 80% by weight, 50% to 75% by weight, 50% to 70% by weight, 50% to 65% by weight, 50% to 60% by weight, 50% to 55% by weight, 55% to 95% by weight, 55% to 90% by weight, 55% to 85% by weight, 55% to 80% by weight, 55% to 75% by weight, 55% to 70% by weight, 55% to 65% by weight, 55% to 60% by weight, 60% to 95% by weight, 60% to 90% by weight, 60% to 85% by weight, 60% to 80% by weight, 60% to 75% by weight, 60% to 70% by weight, 60% to 65% by weight, 65% to 95% by weight, 65% to 90% by weight, 65% to 85% by weight, 65% to 80% by weight,An N-acylaminoalkanesulfonate surfactant of 65% to 75% by weight, 65% to 70% by weight, 70% to 95% by weight, 70% to 90% by weight, 70% to 85% by weight, 70% to 80% by weight, 70% to 75% by weight, 75% to 95% by weight, 75% to 90% by weight, 75% to 85% by weight, 75% to 80% by weight, 80% to 95% by weight, 80% to 90% by weight, 80% to 85% by weight, 85% to 95% by weight, 85% to 90% by weight or 90% to 95% by weight.

[0068] The method may include raising the temperature of the mixture to 190 °C or lower, preferably 170 °C or lower, more preferably 160 °C or lower to form a reaction mixture. The raising step may include raising the temperature of the mixture to about 65 °C to about 190 °C or preferably about 90 °C to about 160 °C. The method may include continuously removing the alkyl alcohol from the reaction mixture.

[0069] (a) The aminoalkanesulfonic acid of formula (II) may include taurine (2-aminoethanesulfonic acid), hypotaurine (3-amino-1-propanesulfonic acid), N-methyltaurine (2-methylaminoethanesulfonic acid) or a combination thereof. (b) The anhydrous alkali metal salts of the aminoalkanesulfonic acid of formula (II) may include sodium 2-aminoethanesulfonate, sodium N-methyltaurinate, sodium 3-aminopropanesulfonate, sodium 3-(N-methylamino)propanesulfonate and combinations thereof.

[0070] Suitable anhydrous bases are selected from the group consisting of: alkali metals such as sodium, lithium and potassium; alloys of two or more alkali metals such as sodium-lithium and sodium-potassium alloys; alkali metal hydrides such as sodium hydride, lithium hydride and potassium hydride; and alkali metal alkoxides, especially those containing from about one to about four carbon atoms such as sodium methoxide, potassium methoxide, lithium methoxide, sodium ethoxide, potassium ethoxide, lithium ethoxide, sodium n-propoxide, potassium n-propoxide, sodium isopropoxide, potassium isopropoxide, sodium butoxide, potassium butoxide, sodium isobutoxide, potassium isobutoxide, sodium sec-butoxide, potassium sec-butoxide and sodium tert-butoxide. The alkoxide can be obtained in solid form or as a solution in the alcohol from which it is derived. The anhydrous base may include C1-C4 alkoxides, preferably methanol solutions of sodium methoxide, potassium methoxide or a combination thereof.

[0071] The mixture may comprise from about 1.00 mole to about 1.50 moles, preferably from about 1.02 moles to about 1.20 moles, and more preferably from about 1.05 moles to about 1.10 moles of an anhydrous base per mole of (a) an aminoalkanesulfonic acid of formula (II). The mixture may comprise from about 0.01 mole to about 0.5 mole, preferably from about 0.02 mole to about 0.2 mole, and more preferably from about 0.05 mole to about 0.1 mole of an anhydrous base per mole of (b) an anhydrous alkali metal salt of an aminoalkanesulfonic acid of formula (II).

[0072] The relative molar amounts in which the alkoxide is added to step i) are in the range of 1.00 to 1.50 moles, 1.02 to 1.20 moles or 1.05 to 1.10 moles per mole of amino acid, specifically listing these ranges and all values within any resulting range. The alkoxide not consumed in the neutralization catalyzes the reaction between the amino acid salt and the fatty alkyl ester. Thus, in the methods described herein, the amount of alkoxide catalyst can be in the range of 2 mol% to 20 mol%, or 5 mol% to 10 mol%, specifically listing these ranges and all values within any resulting range.

[0073] As used herein, the terms "fatty alkyl ester" and "fatty acid ester" are intended to include any compound in which the alcohol moiety is readily removable, such as a volatile alcohol such as C 1-4 esters of alcohols (preferably methyl). Volatile alcohols are highly desirable. Methyl esters are the most highly preferred ester reactants. Suitable ester reactants can be prepared by the reaction of a diazoalkane with a fatty acid or can be derived by the alcoholysis of fatty acids naturally present in fats and oils. Non-limiting examples are methyl octanoate (octanoate), methyl decanoate (decanoate), methyl dodecanoate (laurate), methyl tetradecanoate (myristate), methyl hexadecanoate (palmitate), methyl octadecanoate (stearate), methyl oleate, ethyl dodecanoate (laurate), ethyl tetradecanoate (myristate), isopropyl dodecanoate (laurate), isopropyl tetradecanoate (myristate), and mixtures thereof. Suitable fatty acid esters can be derived from synthetic or natural, saturated or unsaturated fatty acids. Non-limiting examples of saturated fatty acids include octanoic acid, decanoic acid, lauric acid, myristic acid, palmitic acid, and stearic acid. Mixtures of fatty acids are derived from coconut oil, cottonseed oil, palm kernel oil, soybean oil, cottonseed oil, rapeseed oil, safflower oil, canola oil (low erucic acid), and corn oil, and mixtures thereof. Most preferred is coconut oil.

[0074] The fatty alkyl ester is preferably highly purified to remove color / odor substances, oxidation products, and their precursors. The free fatty acid content can be less than about 0.1% by weight of the ester or less than about 0.05%. Additionally, the fatty acid alkyl ester should have as low a water level as possible because any water present will react with the alkoxide catalyst, inhibit the amidation reaction, and can lead to an increased soap level.

[0075] The method can include adding about 0.90 moles to about 1.50 moles, preferably about 0.95 moles to about 1.20 moles, or more preferably about 1.00 moles to about 1.05 moles of the fatty alkyl ester per mole of the alkali metal salt of the aminoalkanesulfonic acid, specifically listing all values within these ranges and any ranges resulting therefrom. As shown in the examples, when (a) the aminoalkanesulfonic acid of formula (II) or (b) the anhydrous alkali metal salt of the aminoalkanesulfonic acid of formula (II) and the fatty alkyl ester are used in approximately equimolar amounts, a highly active surfactant composition with a low level of impurities can be obtained without further processing steps. Using an excess of the fatty alkyl ester will result in the surfactant composition being contaminated with unreacted fatty alkyl ester, and thus further processing will be required to remove this unreacted fatty alkyl ester. Even more undesirable is the use of an excess of (a) the aminoalkanesulfonic acid of formula (II) or (b) the anhydrous alkali metal salt of the aminoalkanesulfonic acid of formula (II) because: (i) it is more expensive than the fatty alkyl ester, (ii) it does not have surface-active properties, and (iii) it will be difficult and expensive to recover the unreacted amino acid salt from the surfactant mixture.

[0076] Surprisingly, the reaction between (a) the aminoalkanesulfonic acid of formula (II) or (b) the anhydrous alkali metal salt of the aminoalkanesulfonic acid of formula (II) and the fatty alkyl ester of formula (III) can be carried out at atmospheric pressure or even under negative pressure while continuously distilling out the alkyl alcohol (e.g., methanol) from the reaction mixture. The temperature conditions for the amidation reaction can be in the range of about 65°C to about 190°C or about 90°C to about 160°C, specifically listing all values within these ranges and any ranges resulting therefrom. The progress of the reaction can be monitored by tracking the amount of alkyl alcohol collected and / or by quantitative 1 1H NMR or other analytical techniques. The final highly active N-acylaminoalkanesulfonate surfactant reaction mixture prepared under these conditions can be milled, tableted, granulated, pelletized, and / or formed into beads, noodles, needles, and ribbons by methods known to those skilled in the art.

[0077] The reaction can utilize an inert gas headspace to help reduce the level of oxygen available during the reaction. The reduced oxygen level helps reduce the amount of oxidation of the reaction components. Oxidation of the components can cause discoloration. Suitable examples of inert gases that can be used are nitrogen.

[0078] In addition, the advantage of conducting the reactions described herein at atmospheric pressure or even negative pressure is that the resulting surfactant can be substantially solvent-free, if desired. Additionally, the alkyl alcohol (e.g., methanol) vapor can be condensed and recovered outside the reactor. This collection of alkyl alcohol vapor can be reused to prepare more methyl esters. The resulting surfactant can have less than about 5.0 wt% fatty acid methyl ester, less than about 3.0 wt% or less than about 2.0 wt% fatty acid methyl ester, specifically listing these ranges and all values within any resulting range.

[0079] One of the advantages of the method of the present disclosure is that the resulting N-acylaminoalkane sulfonate surfactant of formula (I) can be made substantially solvent-free, without using excessive reactants, of high purity and without the need for additional purification steps.

[0080] To prepare a surfactant composition that can be pumped (able to be pumped at 50 °C or below), the active surfactant mixture without any further purification can be diluted into water in an amount of 20 wt% to 70 wt% surfactant mixture, and about 25 wt% to about 50 wt% surfactant mixture. Alternatively, water can be added to the highly active surfactant activator mixture with good mixing at a temperature below 120 °C or at a temperature below 100 °C. The amount of water required will depend on the target surfactant activity level, target viscosity, and solubility characteristics of the surfactant. The surfactant in solid form (powder, flakes, granules, beads, needles, noodles) can also be dissolved in water to prepare a surfactant composition that can be pumped, for easy incorporation by formulators into cleaning formulations.

[0081] The method can be carried out in a suitable reactor configuration in batch, semi-continuous, or continuous mode. A conventional stirred tank batch reactor known to those skilled in the art, equipped with means for heating the reaction, a vapor column and condenser for collecting the volatile alkyl alcohol, an efficient stirrer capable of agitating the reaction product mixture, means for blanketing the reactor contents with nitrogen, and optionally a vacuum system capable of achieving a vacuum of less than 20 mm Hg, can be used to prepare the N-acylaminoalkane sulfonate surfactant compositions disclosed herein.

[0082] Other reactors useful for the present disclosure are suitably such devices where shear forces can be used to mix liquids as well as liquid and solid mixtures of solid substances. In a static housing, the movement of the reaction mixture is caused by internal mechanical stirring or mixing devices. The reaction device can be a kneader or mixer equipped with sigma blades, chewing blades, or plow-type stirrers. Other useful devices include horizontal or vertical forced mixers equipped with mixing tools such as sigma blades, chewing blades, plow-type stirrers, or mixing paddles, combined with a cutting rotor.

[0083] Suitable horizontal forced mixers are those equipped with a mixing tool or a combination of mixing tools, such as, for example, sigma blades, chewing blades or plow agitators, in combination with a cutting rotor mounted in a drum; more preferably a horizontal forced mixer operating at a Froude number between 0.1 and 6, between 0.25 and 5 or between 0.4 and 4 and equipped with a mixing tool or a combination of mixing tools, the mixing tools such as, for example, sigma blades, chewing blades and plow agitators, in combination with a cutting rotor mounted in a drum. Without wishing to be bound by theory, in the treatment of the mixing process, the Froude number Fr plays a major role. This dimensionless quantity represents the relationship between the inertial force acting on a moving particle and gravity. The following formula applies:

[0084] Fr = v 2 / rg

[0085] where:

[0086] v = circumferential velocity [m / s]

[0087] r = radius of the mixing drum [m]

[0088] g = acceleration due to gravity [m / s 2

[0089] V = π × D × n / 60

[0090] where:

[0091] D = diameter of the mixing drum [m]

[0092] N = rotational speed of the shaft [rpm]

[0093] The N-acyl aminoalkane sulfonate surfactant compositions and preparation methods described herein have many advantages compared to known commercial manufacturing methods and include:

[0094] 1) A highly active surfactant composition substantially free of solvents and halogen salts such as sodium chloride.

[0095] 2) High conversion rates and yields can be achieved while avoiding laborious purification steps and attendant product losses.

[0096] 3) Fewer chemical engineering unit operations can result in a significant reduction in energy consumption.

[0097] 4) As described herein, it does not contain toxic and hazardous reagents and therefore there are no problems in handling these materials.

[0098] 5) The resulting surfactant is substantially free of solvents which would otherwise need to be removed by additional post-reaction processing steps as the solvent limits and / or affects the application and / or formulatability of the surfactant.​

[0099] 6) Production of N-acylaminoalkanesulfonates from fatty alkyl esters.

[0100] 7) The conversion rate and yield are at least 75%, preferably 80% or higher.

[0101] 8) Lower the reaction temperature.

[0102] 9) Eliminate the need for preparing fatty acid chlorides.

[0103] 10) Avoid using an excessive amount of fatty acid (which ultimately contaminates the product and requires subsequent removal).

[0104] 11) There is no waste stream, and the recovered methanol can be recycled to prepare fatty alkyl esters.

[0105] 12) React at atmospheric pressure (non-pressurized conditions).

[0106] It is desirable to add a solvent to the method because the amount of methanol supplied by a catalytic amount of anhydrous base, sodium methoxide solution, or generated by the amidation reaction is not sufficient to overcome the lack of miscibility / compatibility between the alkali metal salt of the aminoalkanesulfonic acid and the fatty alkyl ester. The solvent can be the same as or different from methanol, but preferably the same as the solvent present in the anhydrous base and the same as the solvent formed in the amidation reaction.

[0107] After the aminoalkanesulfonic acid contacts the anhydrous base, a white, solid, agglomerate-like substance can be formed. Therefore, it is expected that a lower conversion rate and yield of the N-acylaminoalkanesulfonate surfactant can be achieved by first adding the aminoalkanesulfonic acid to the anhydrous base (sodium methoxide solution) and then adding the fatty alkyl ester. Therefore, in this method, it is preferred to form the alkali metal salt of the aminoalkanesulfonic acid in situ by adding the aminoalkanesulfonic acid to a mixture composed of the anhydrous base and the fatty alkyl ester. Without being bound by theory, this is advantageous because the resulting alkali metal salt of the aminoalkanesulfonic acid formed is finely dispersed or soluble in the mixture containing the fatty alkyl ester.

[0108] Applications and uses

[0109] In another aspect, the present disclosure relates to a consumer cleaning or personal care composition comprising from about 0.001 wt% to about 99.999 wt% or from about 0.1 wt% to about 80 wt% of an N-acylaminoalkane sulfonate surfactant as described herein, based on the total weight of the composition, and from 0.001 wt% to about 99.999 wt% of one or more additional cleaning components, or one or more additional personal care components. In various embodiments, at least one cleaning component is selected from the group consisting of surfactants, enzymes, builders, alkaline systems, organic polymeric compounds, color dyes, bleaching compounds, alkanolamines, soil suspending agents, anti-redeposition agents, corrosion inhibitors, and mixtures thereof. In some cases, the composition is selected from the group consisting of granular detergents, bar detergents, liquid laundry detergents, liquid hand dishwashing compositions, hard surface cleaners, tablets, disinfectants, industrial cleaners, highly dense liquids, powders, and stain removers. In one class of cases, the composition is encapsulated in a sachet or multi-compartment bag comprising solid and liquid compartments.

[0110] In some embodiments, at least one personal care component is selected from the group consisting of oils and emollients, humectants, carriers, extracts, vitamins, minerals, anti-aging compounds, surfactants, solvents, polymers, preservatives, antimicrobials, waxes, particles, colorants, dyes, fragrances, and mixtures thereof. In various cases, the composition is a shampoo, hair conditioner, hair treatment, facial soap, bath agent, bath bar, foam bath, makeup remover balm, skin care product, acne control product, deodorant, antiperspirant, shaving aid, cosmetic, depilatory, fragrance, and mixtures thereof. In one class of cases, the composition is delivered in a form selected from the group consisting of wipes, cloths, bars, liquids, powders, creams, lotions, sprays, aerosols, foams, mousses, serums, capsules, gels, emulsions, puff applicators, rollers, sticks, sponges, ointments, pastes, emulsion sprays, tonics, cosmetics, and mixtures thereof. In various embodiments, the composition further includes a product selected from the group consisting of devices, appliances, applicators, tools, combs, brushes, substrates, and mixtures thereof. In some embodiments, the composition is dispensed from an article selected from the group consisting of bottles, jars, tubes, sachets, bags, containers, pump bottles, vials, ampoules, compacts, wipes, and mixtures thereof.

[0111] Additional method embodiments

[0112] In an embodiment, the method may include an amidation reactor. In an embodiment, an aminoalkanesulfonic acid stream, an anhydrous base stream, and a fatty alkyl ester stream are fed into the amidation reactor, which produces a first stream having an N-acylaminoalkanesulfonate surfactant and a second stream having an alkyl alcohol vapor entraining the fatty alkyl ester. In an embodiment, an alkyl alcohol recovery step may be added, which separates any fatty alkyl ester entrained in the second stream (alkyl alcohol vapor stream) to form a third stream (fatty alkyl ester stream) and recovers the alkyl alcohol and produces a fourth stream, which is the recovered alkyl alcohol, which may be used as is or optionally after further purification in the preparation of fatty alkyl esters or in a separate process for other uses. The third stream of the composition having the fatty alkyl ester and the alkyl alcohol may optionally be further purified.

[0113] In an embodiment, a solid handling (cooling-crushing / grinding) unit may be added. In this embodiment, the first stream (N-acylaminoalkanesulfonate surfactant) is then fed to the solid handling unit to form an N-acylaminoalkanesulfonate surfactant product stream. In an embodiment, the N-acylaminoalkanesulfonate surfactant product stream is no longer hot and is substantially free of impurities including water, salt (NaCl), polyol solvent, alkyl alcohol.

[0114] In an embodiment, a dissolution unit / reactor may be added. In this embodiment, the first stream (N-acylaminoalkanesulfonate surfactant) is fed into the dissolution unit to produce an N-acylaminoalkanesulfonate surfactant aqueous solution stream.

[0115] In an embodiment, a second amidation reactor may be added. In an embodiment, the second amidation reactor may operate in parallel or in series with the first amidation reactor. In an embodiment where the second amidation reactor operates in parallel with the first amidation reactor, the second amidation reactor produces a fifth stream having an alkyl alcohol vapor entraining the fatty alkyl ester. The fifth stream may be fed to the alkyl alcohol recovery unit after being combined with the alkyl alcohol vapor stream from the first amidation reactor. Without being bound by theory, adding the second amidation reactor provides a convenient and effective way to increase product yield, schedule reactor maintenance and / or repair without increasing the manufacturing plant footprint and the capital expenditure for installing a second alkyl alcohol recovery unit and facilities (hot oil boiler system).

[0116] Examples

[0117] Analysis by chromatography / mass spectrometry showed / confirmed the presence of N-acyl-N-methylaminoalkane sulfonate in the product obtained from the reaction of N-acylaminoalkane sulfonate. The sample was weighed and diluted to a concentration of 1 mg / mL with 100% MeOH (assuming 100% purity). The solution was further diluted to 50 ppm with 50 / 50 MeOH / water. The sample was analyzed by UPLC-CAD-HRMS on a reversed-phase ACQUITY UPLC BEH C18 2.1×150 mm (5 μL injection). Full scan and MS2 scan information were collected in two negative ion electrospray modes.

[0118] Further analysis of the sample by two DNMR experiments further confirmed the presence of N-acyl-N-methylaminoalkane sulfonate and NMR peak assignments were made.

[0119] By 1 H NMR method, the reaction product was analyzed.

[0120] In a scintillation vial, the reaction product and internal standard (IS) (0.1 mg readability) were weighed on a precision balance. A 2:1 v / v solvent mixture of deuterated chloroform-methanol (CDCl3-CD3OD) was added to the vial to completely dissolve the sample and IS (sometimes one or two drops of D2O were needed to completely dissolve the sample). Quantitative 1 H NMR spectra were recorded at 600 MHz using a standard 1 H pulse sequence, a pulse width of 12.00, a delay of 60 seconds, and an acquisition time of 2.59 seconds. The NMR data were processed using MestReNova software version 14.2.1. The integral of the triplet corresponding to the methylene (-CH2-) group of the N-acylaminoalkane sulfonate surfactant at δ 3.54 - 3.56 ppm was used to calculate the weight %. The integrals of the peaks at δ 3.73 - 3.76 and 3.68 - 3.71 ppm corresponding to the rotamers of the methylene (-CH2-) group of the N-acyl-N-methylaminoalkane sulfonate surfactant were used to calculate the weight %. The integral of the singlet corresponding to the methyl (CH3-) of any residual fatty acid methyl ester at δ 3.65 ppm was used to calculate the weight %. The integrals were compared with the integral region of the IS and used for calculation. The weight % of each substance was calculated using the following formula:

[0121]

[0122] Weight % (y) = weight percentage of substance "y" in the sample

[0123] A = NMR integral

[0124] n = number of protons

[0125] MW = molecular weight

[0126] P = Purity of internal standard

[0127] Repeat the same steps, but dissolve the sample and IS in deuterium oxide (D2O). The integral of the triplet of the methylene (-CH2-) group attributed to the N-acylaminalkanesulfonate surfactant at δ 3.56 - 3.59 ppm is used to calculate the weight %. And the integral of the triplet of the methylene (-CH2-C(O)-OM) adjacent to the carboxyl group at δ 2.16 - 2.18 ppm is used to calculate the weight % of the fatty acid soap. The soap content cannot be quantified in the deuterochloroform-methanol (CDCl3-CD3OD) solvent system because the soap peak (-CH2-C(O)-OM) partially overlaps with another peak (-CH2-C(O)-NH-) corresponding to the surfactant, but does not overlap in D2O.

[0128] Equipment : Transformation is carried out using a horizontal forced mixer equipped with a plow-shaped stirrer. It is equipped with a thermocouple installed in a mixing drum with a digital temperature reader, a heating jacket with a maze design to ensure uniform flow around the mixing drum, a condenser suitable for attaching to the flange port on the top of the container, a receiver on a weighing balance, and an inert gas inlet. A discharge port using a manual ball valve is provided at the bottom of the mixing drum. The mixer is heated using a heating circulator with a heating fluid. The reaction product is unloaded into a glass baking tray. The amount (grams) of condensed methanol, the temperature (°C) of the reaction mixture, and the inlet temperature (°C) of the heating fluid are measured in real time.

[0129] Raw materials used :

[0130] 2-Aminoethanesulfonic acid (taurine), crystalline solid

[0131] Sodium methoxide solution - a methanol solution of approximately 25 wt%

[0132] CE-1270-C 12 and C 14 Lauric acid / myristic acid 75 / 25 blend of methyl esters

[0133] Coconut fatty acid methyl ester (coconut FAME) - The carbon chain length distribution range of coconut fatty acid methyl ester is shown as follows:

[0134] C8 = 0% - 10%

[0135] C 10 = 0% - 7%

[0136] C 12 = 50% - 65%

[0137] C 14= 18% - 22%

[0138] C 16 = 0% - 10%

[0139] C 18 = 0% - 10%

[0140] C 18-1 = 0% - 7%

[0141] Examples 1-4

[0142] Preparation of sodium C1214 taurate

[0143] Under nitrogen, CE - 1270 (769.0 g, 3.46 mol), sodium methoxide (790.8 g, 3.53 mol), and taurine (413.0 g, 3.30 mol) were added to the reactor and mixed at a temperature of 22°C - 35°C. The temperature of the reaction mixture was gradually increased. The mixer was operated according to the rheology of the composition at a Froude number between 0.4 and 2. The temperature of the reaction mixture was gradually increased. When the temperature of the reaction mixture reached 68°C - 69°C, methanol began to distill out and condense and remained stable for some time. When approximately ≥60% of the total theoretical amount of the expected methanol had been collected, the temperature of the reaction mixture began to rise steadily. The contents of the reactor were heated to 168°C. The reaction mixture was maintained at 165°C - 168°C for 110 minutes. Methanol from the base and methanol formed during the reaction distilled out and condensed as the temperature rose. Then the mixer and its contents were cooled to ambient temperature while the shaft with the plow - type mixing elements continued to rotate. After opening the ball valve, the powdered product was unloaded from the mixing drum through the bottom port. After removing the front cover bolted to the mixing drum, additional product was collected manually. A yield of 1100 g of off - white solid powder was obtained.

[0144] Other experiments were conducted to evaluate the effects of temperature and time, which are summarized in Table A. The starting materials and conditions were the same as in Experiment 1, except where otherwise noted by footnotes.

[0145] Table A

[0146]

[0147] a C chain length distribution: C8 = 10.2%, C 10 = 7.4%, C 12 = 57.4%, C 14 = 20.6%, C 16 = 4.1%; NMT = N - methyl taurinate; n / a = not available

[0148] b is calculated as the relationship between the molar amount of the formed taurate surfactant and the number of moles of taurine consumed.

[0149] c is calculated as the relationship between the mass of the formed taurate surfactant and the maximum total weight of the taurate surfactant that can be produced.

[0150] 10 wt% solution of surfactant in deionized water, Lovibondò PFX-i series, S / N 104146,

[0151] 100 mm cell path.

[0152] As shown in Table A, Example 2 shows that compared with Example 1, a 10-degree drop in temperature results in slightly lower conversion and yield, although the time is extended at this temperature. Compared with Example 1, similar conversion and yield were obtained in Example 3 with a 20-degree increase in temperature and a 70-minute increase in time. However, as shown by the APHA and Gardner values, the product relatively exhibits more color development. Example 4 shows that compared with Example 1 using FAME with C8 and C 10 carbon chains in the composition, the reaction produces a product of similar quality at the same temperature but in a shorter time. These experiments show that temperature and the time at that temperature are key parameters to achieve good conversion and yield, and there is an optimal range for carrying out this reaction with low color development.

[0153] Examples 5-8

[0154] Carbon chain length distribution of Coco FAME used in this experiment: C8 = 8.6%, C 10 = 6.2%, C 12 = 50.1%, C 14 = 18.0, C 16 = 8.8% and C 18 : 0 = 8.1%.

[0155] Preparation of sodium cocoyl taurate

[0156] Under nitrogen, add Coco FAME (768.5 g, 3.50 mol), sodium methoxide (839.5 g, 3.75 mol) and taurine (438.2 g, 3.50 mol) to the reactor and mix at a temperature of 22 °C - 35 °C. Gradually increase the temperature of the reaction mixture. Operate the mixer according to the rheology of the composition at a Froude number between 0.4 and 2. Gradually increase the temperature of the reaction mixture. When the temperature of the reaction mixture reaches 68 °C - 69 °C, methanol starts to distill out and condense and remains stable for some time. When about ≥60% of the total theoretical amount of the expected methanol has been collected, the temperature of the reaction mixture starts to rise steadily. Heat the contents in the reactor to 191 °C. Hold the reaction mixture at 188 °C - 191 °C for 120 minutes. Methanol from the base and methanol formed during the reaction distill out and condense as the temperature rises. Then cool the mixer and its contents to ambient temperature while the shaft with the plow-shaped mixing elements continues to rotate. After opening the ball valve, unload the powdered product from the mixing drum through the bottom port. After removing the front cover bolted to the mixing drum, manually collect the additional product.

[0157] The powder product contains 75.0 wt% sodium cocoyl taurate, 7.3 wt% sodium cocoyl N-methyl taurate, 9.1 wt% fatty acid soap, 0.5 wt% FAME. Measured in a Lovibond PFX-i series, S / N 104146, 100 mm cell path, the solution of this surfactant (10 wt% active surfactant) exhibits a Gardner value = 4.7 and APHA = 104.

[0158] Additional experiments were carried out using coCo FAME with unsaturated C chains for evaluation. They are summarized in Table B. The FAME feedstock used had a pale yellow hue when compared to the fully saturated form used in Example 5. The reactants and conditions were the same as in Example 5, except where otherwise noted by footnotes. Examples 6 and 8 produced sodium cocoyl taurate surfactant compositions of similar quality to the fully saturated form in Example 5. However, it was observed that the higher temperature and time in Example 8 led to an increase in color development. On the other hand, Example 7 showed that the time at this temperature was not long enough to convert the reactants to products, which could be observed by the relatively high content of FAME in the surfactant composition.

[0159] Table B

[0160]

[0161] a C chain length distribution: C8 = 8% - 8.6%, C 10 = 5.7% - 6.2%, C 12= 50.0%, C 14 = 18.0%, C 16 = 9% - 10%, C 18∶0 = 0.9%, C 18∶1 = 6.5% - 6.7%

[0162] b A 10 wt% solution of surfactant in deionized water PFX-i series, S / N 104146, 100 mm cell path

[0163] NMT = N-methyl taurate; n / a = not available

[0164] Example 9

[0165] The carbon chain length distribution of the FAME used in this experiment: C 12 = 59.3%, C 14 = 21.3, C 16 = 9.1% and C 18∶0 = 1.3%, C 18∶1 = 8.2%, C 18∶2 = 0.6%.

[0166] Preparation of sodium C12-C18 taurate

[0167] Under nitrogen, FAME (802.9 g, 3.47 mol), sodium methoxide (795.3 g, 3.53 mol) and taurine (413.0 g, 3.30 mol) were added to the reactor and mixed at a temperature of 22 °C - 35 °C. The temperature of the reaction mixture was gradually increased. The mixer was operated according to the rheology of the composition at a Froude number between 0.4 and 2. The temperature of the reaction mixture was gradually increased. When the temperature of the reaction mixture reached 70 °C - 71 °C, methanol began to distill out and condense and was kept stable for some time. When about ≥60% of the total theoretical amount of the expected methanol had been collected, the temperature of the reaction mixture began to rise steadily. The contents of the reactor were heated to 172 °C. The reaction mixture was kept at 169 °C - 172 °C for 210 minutes. Methanol from the base and methanol formed during the reaction distilled out and condensed as the temperature rose. Then the mixer and its contents were cooled to ambient temperature while the shaft with the plow-type mixing elements continued to rotate. After opening the ball valve, the light yellow "granular" product was unloaded from the mixing drum through the bottom port. After removing the front cover bolted to the mixing drum, additional product was collected manually.

[0168] The powdery product contains 75.5 wt% sodium C1218 taurate, 6.7 wt% N-methyl sodium C1218 taurate, 9.6 wt% fatty acid soap, and 2.2 wt% FAME. Measured in a Lovibond PFX-i series, S / N 104146, 100 mm cell path, a solution of this surfactant (10 wt% active surfactant) exhibits a Gardner value = 11.3 and an APHA > 505.

[0169] Example 10

[0170] Carbon chain length distribution of FAME used in this experiment: C 12 = 60.4%, C 14 = 21.7, C 16 = 8.5% and C 18 :0 = 1.0%, C 18 :1 = 7.4%, C 18 :2 = 0.5%.

[0171] Preparation of sodium N-methyl C12-C18 taurate

[0172] Under nitrogen, FAME (809.2 g, 3.50 mol), sodium methoxide (59.4 g, 0.25 mol), 250 mL of methanol, and dry N-methyl sodium taurate (576.6 g, 3.58 mol) were added to the reactor and mixed at a temperature of 22 °C - 35 °C. The temperature of the reaction mixture was gradually increased. The mixer was operated according to the rheology of the composition at a Froude number between 0.4 and 2. The temperature of the reaction mixture was gradually increased. When the temperature of the reaction mixture reached 74 °C and began to rise steadily, methanol began to distill out and condense. The contents of the reactor were heated to 182 °C. The reaction mixture was maintained at 179 °C - 182 °C for 70 minutes. As the temperature rose, all the methanol was distilled out and condensed. Then the mixer and its contents were cooled to ambient temperature while the shaft with the plow-type mixing elements continued to rotate. After removing the front cover bolted to the mixing drum, the off-white reaction product was manually unloaded. It contains 55.0 wt% N-methyl sodium C1218 taurate, 10.3 wt% fatty acid soap, 13.6 wt% FAME, and an undetermined level of N-methyl taurate.

[0173] Example 11

[0174] Comparative examples

[0175] Effect of added glycerol

[0176] This example shows that the presence of glycerol as a solvent results in a significant decrease in the conversion rate of taurine and the yield of surfactant.

[0177] The carbon chain length distribution of the FAME used in this experiment: C8 = 6.4%, C 10 = 64.9%, C 12 = 62.9%, C 14 = 22.6, C 16 = 2.6%.

[0178] Preparation of sodium C8-C16 taurate

[0179] Under nitrogen, FAME (1148.2 g, 5.36 mol), sodium methoxide (1220.4 g, 5.74 mo1), glycerol (177.1 g) and taurine (670.9 g, 5.36 mol) were added to the reactor and mixed at a temperature of 22 °C - 35 °C. The temperature of the reaction mixture was gradually increased. The mixer was operated according to the rheology of the composition at a Froude number between 0.4 and 2. The temperature of the reaction mixture was gradually increased. When the temperature of the reaction mixture reached 68 °C - 69 °C, methanol began to distill out and condense and was maintained for a stable period of time. The contents in the reactor were heated to 157 °C. The reaction mixture was maintained at 155 °C - 157 °C for 120 minutes. Methanol from the base and the methanol formed during the reaction distilled out and condensed as the temperature increased. Then the mixer and its contents were cooled to ambient temperature while the shaft with the plow-shaped mixing element continued to rotate. After removing the front cover bolted to the mixing drum, the pasty reaction product with the odor of heavy fatty acid methyl ester was manually unloaded from the reactor. It contained 24.6 wt% of sodium taurate C8 - C16, 5.6 wt% of fatty acid soap, 21.8 wt% of FAME and 26.3 wt% of sodium taurate.

[0180] Example 12

[0181] 130L reactor size

[0182] Under nitrogen, fatty acid methyl ester CE1270 (methyl laurate / methyl myristate, purchased from P&G Chemicals) (29.0 kg), sodium methoxide solution (25 wt% methanol solution, purchased from Sigma - Aldrich) (29.1 kg), and 2 - aminoethanesulfonic acid (taurine purchased from Spectrum Chemical Mfg. Corp.) (15.7 kg) were added to a 130 - liter horizontal forced mixer (FM - 130 Plow batch mixer, purchased from B&P Littleford). The mixer was equipped with a plow - type agitator and a high - temperature heating jacket (hot oil) mounted on an industrial digital floor scale, and was equipped with a double - condenser and double - receiver system as well as an inert gas inlet. The mixture was gradually brought to 150 °C over 10 hours, during which the methanol evaporated was condensed outside the mixer. Any fatty acid methyl ester entrained in the methanol vapor was condensed (approx. 70 °C - 80 °C condenser) and collected in the first receiver, while the methanol was condensed (approx. 5 °C - 10 °C condenser) and collected in the second receiver. The reaction mixture was maintained at 150 °C - 160 °C for 2 hours. The methanol collected was 30.0 kg. Then the mixer and the product material therein were cooled to ambient temperature while the shaft with the plow - type mixing elements continued to rotate. The powdered product flowed freely and was unloaded from the mixer through the discharge port at the bottom of the vessel into a lined fiber drum. A yield of 42.6 kg was collected. The final product had the following composition as determined by NMR analysis: 74.15 wt% sodium C1214 taurate, 7.05 wt% sodium C1214 N - methyl taurate, 7.80 wt% fatty acid soap, 4.75 wt% FAME. In a Lovibond PFX - i series, S / N 104146, measured in 10 - mm and 100 - mm cell paths respectively, a solution of this surfactant (10 wt% active surfactant) showed a Gardner value = 0.3 and APHA = 68.5. NMR analysis was performed using a Bruker Avance III 600 MHz w / SampleJet magnetic resonance spectrometer. Processing was carried out using MestReNova software version 14.2.1 purchased from Mestrelab.

[0183] Example 13

[0184] 130L reactor size

[0185] Under nitrogen, fatty acid methyl ester CE1270 (methyl laurate / methyl myristate, purchased from P&G Chemicals) (36.2 kg), sodium methoxide solution (25 wt% methanol solution, purchased from Sigma-Aldrich (36.1 kg)), and 2-aminoethanesulfonic acid (taurine purchased from Spectrum Chemical Mfg. Corp.) (19.5 kg) were added to a 130-liter horizontal forced mixer (FM-130 Plow batch mixer, purchased from B&P Littleford). The mixer was equipped with a plow-type agitator and a high-temperature heating jacket (hot oil) mounted on an industrial digital weighbridge, and was equipped with a double condenser and double receiver system as well as an inert gas inlet. The mixture was gradually brought to 150 °C over 7 hours, during which the methanol evaporated was condensed outside the mixer. Any fatty acid methyl ester entrained in the methanol vapor was condensed (at approximately 70 °C - 80 °C condenser) and collected in the first receiver, while the methanol was condensed (at approximately 5 °C - 10 °C condenser) and collected in the second receiver. The reaction mixture was held at 150 °C - 160 °C for 2.5 hours. The methanol collected was 37.0 kg.

[0186] The mixer and the product material therein were then cooled to ambient temperature while the shaft with the plow-type mixing elements continued to rotate. The powdered product flowed freely and was unloaded from the mixer through the discharge port at the bottom of the vessel into a lined fiber drum. A yield of 53.7 kg was collected. The final product had the following analysis: 72.40 wt% sodium C1214 taurate, 9.10 wt% sodium C1214 N-methyl taurate, 8.85 wt% fatty acid soap, 3.80 wt% FAME. In a Lovibond PFX-i series, S / N 104146, measured in 10 mm and 100 mm cell paths respectively, a solution of this surfactant (10 wt% active surfactant) showed a Gardner value = 0.4 and APHA = 77.3. NMR analysis was performed using a Bruker Avance III 600 MHz w / SampleJet magnetic resonance spectrometer. Processing was performed using MestReNova software version 14.2.1 purchased from Mestrelab.

[0187] Example 14

[0188] Preparation and dissolution

[0189] 130L reactor size

[0190] Under nitrogen, fatty acid methyl ester CE1270 (methyl laurate / methyl myristate, purchased from P&G Chemicals) (41.2 kg), sodium methoxide solution (25 wt% methanol solution, purchased from Sigma - Aldrich) (40.9 kg), and 2 - aminoethanesulfonic acid (taurine purchased from Spectrum Chemical Mfg. Corp.) (22.2 kg) were added to a 130 - liter horizontal forced mixer (FM - 130 Plow batch mixer, purchased from B&P Littleford). The mixer was equipped with a plow - type agitator and a high - temperature heating jacket (hot oil) mounted on an industrial digital weighbridge, and was equipped with a double - condenser and double - receiver system as well as an inert gas inlet. The mixture was gradually brought to 150 °C over 6.5 hours, during which the methanol evaporated was condensed outside the mixer. Any fatty acid methyl ester entrained in the methanol vapor was condensed (at about 70 °C - 80 °C condenser) and collected in the first receiver, while the methanol was condensed (at about 5 °C - 10 °C condenser) and collected in the second receiver. The reaction mixture was held at 150 °C - 160 °C for 3.5 hours. Then the hot reaction product material was discharged into a container located below the mixer. The container contained water at ambient temperature and was equipped with an impeller. The top of the container was covered by a housing that connected the top of the container to a contoured discharge opening at the bottom of the mixer. An N2 gas stream flowed through the system to displace any air and blanket the discharge system. The hot reaction product material was transferred out of the mixer by opening the discharge port gate, causing the material to fall into the water - containing container while being mixed with the impeller to dissolve and cool the surfactant, resulting in a 61 °C concentrated aqueous surfactant solution.

[0191] The mixer was relatively clean. After cooling, it was checked that there was approximately 100 g of residual solid product inside. The residual solid was ground and analyzed: 70.2 wt% sodium C1214 taurate, 4.3 wt% sodium C1214 N - methyl taurate, 8.1 wt% fatty acid soap, 8.3 wt% FAME. In a Lovibond PFX - i series, S / N 104146, measured in 10 - mm and 100 - mm cell paths respectively, a solution of this surfactant (10 wt% active surfactant) showed a Gardner value = 0.3 and APHA = 58.9. NMR analysis was performed using a Bruker Avance III 600 MHz w / SampleJet magnetic resonance spectrometer. Processing was performed using MestReNova software version 14.2.1 purchased from Mestrelab.

[0192] Each document cited herein, including any cross-referenced or related patent or patent application and any patent application or patent from which this application claims priority or benefits thereof, is hereby incorporated by reference in its entirety unless expressly excluded or otherwise limited. The citation of any document is not an admission that it is prior art with respect to any subject matter disclosed or claimed herein or that it alone or in any combination with any other reference teaches, suggests, or discloses any such subject matter. Further, when any meaning or definition of a term in this invention conflicts with any meaning or definition of the same term in a document incorporated by reference, the meaning or definition assigned to the term in this invention shall govern.

[0193] Although specific embodiments of the present disclosure have been illustrated and described, it will be apparent to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the disclosure. Accordingly, it is intended that all such changes and modifications that fall within the scope of the present disclosure be covered by the appended claims.

Claims

1. A surfactant composition, the surfactant composition comprising: N-acylaminoalkanesulfonate of formula (I) greater than 75% by weight based on the weight of the surfactant composition: Wherein: R is a C5-C 21 alkyl substituent, R1 represents H or a C1 to C4 alkyl group, n is an integer from 1 to 2, and M is a cationic group selected from alkali metal salts and hydrogen, and the surfactant composition is substantially free of solvents and NaCl.

2. The composition according to any one of the preceding claims: The composition further comprises at least 5% by weight, preferably from about 5% to about 15% by weight, more preferably from about 8% to about 10% by weight of an N-acyl-N-methylaminoalkanesulfonate surfactant based on the weight of the surfactant composition; Preferably, wherein the alkyl substituent is saturated; Preferably, wherein the alkyl substituent is unbranched; Preferably, wherein R is C 7-17 alkyl substituent; and Preferably, wherein the surfactant composition is substantially free of polyol solvents and water.

3. The surfactant composition according to any one of the preceding claims, the surfactant composition comprising greater than 85% by weight of an N-acylaminoalkanesulfonate surfactant based on the weight of the surfactant composition.

4. The surfactant composition according to any one of the preceding claims, the surfactant composition further comprising from 0% to 1% by weight of an alkyl alcohol (R'OH) based on the weight of the composition.

5. The surfactant composition according to any one of the preceding claims, the surfactant composition comprising less than about 5%, or more preferably less than about 3% by weight of fatty acid methyl ester based on the weight of the surfactant composition.

6. The surfactant composition according to any one of the preceding claims, wherein: The surfactant composition is selected from: powders, granules, tablets, noodles, needles, extrudates, ribbons, beads and pellets, and mixtures thereof; Preferably, the surfactant composition is in a form selected from: granular detergents, bar detergents, liquid laundry detergents, gel detergents, single-phase or multi-phase unit dose detergents, detergents contained in single-phase or multi-phase or multi-compartment water-soluble sachets, liquid hand dishwashing compositions, laundry pre-treatment products, surfactants on or in porous matrices or non-woven sheets, automatic dishwashing detergents, hard surface cleaners, fabric softener compositions, personal care compositions, and mixtures thereof.

7. A method for preparing a surfactant composition comprising an N-acylaminoalkanesulfonate surfactant, the method comprising: Combining the following: (a) an aminoalkanesulfonic acid of formula (II) or (b) an anhydrous alkali metal salt of an aminoalkanesulfonic acid of formula (II): wherein R1 represents H or a C1 to C4 alkyl group, n is an integer from 1 to 2, and M is a cationic group selected from alkali metal salts and hydrogen, anhydrous base, and a fatty alkyl ester of formula (III) wherein R is selected from C5-C 21 alkyl substituents, and R' is a C1 or higher alkyl substituent, preferably methyl, to form a mixture comprising: an N-acylaminoalkanesulfonate of formula (I): wherein: R is a C5-C 21 alkyl substituent, R1 represents H or a C1 to C4 alkyl group, n is an integer from 1 to 2, and M is a cationic group selected from alkali metal salts and hydrogen; raising the temperature of the mixture to 190 °C or lower, preferably 170 °C or lower, more preferably 160 °C or lower, to form a reaction mixture; and continuously removing the alkyl alcohol from the reaction mixture.

8. The method according to claim 7, wherein the surfactant composition further comprises at least 5% by weight, preferably from about 5% to about 15% by weight, more preferably from about 8% to about 10% by weight, based on the weight of the surfactant composition, of an N-acyl-N-methylalkanesulfonate surfactant.

9. The method according to claim 8, wherein R1 is H and the anhydrous base comprises sodium methoxide.

10. The method according to any one of claims 7 to 9, wherein: The combining step comprises: preparing a suspension of the aminoalkanesulfonate of formula (II) by adding the fatty alkyl ester of formula (III) to the anhydrous alkali metal salt of the aminoalkanesulfonic acid of formula (II), and contacting the suspension with the anhydrous base to form the mixture.

11. The method according to any one of claims 7 to 9, wherein the combining step comprises combining the anhydrous base and the fatty alkyl ester of formula (III) to form a premix, and then adding (a) the aminoalkanesulfonic acid of formula (II) or (b) the anhydrous alkali metal salt of the aminoalkanesulfonic acid of formula (II) to the premix to form the mixture.

12. The method according to any one of claims 7 to 11, wherein raising the temperature of the mixture comprises raising the temperature of the mixture to from about 65 °C to about 190 °C, preferably from about 90 °C to about 160 °C.

13. The method according to any one of claims 7 to 12, wherein: (a) The aminoalkanesulfonic acid of formula (II) is selected from taurine (2-aminoethanesulfonic acid), homo-taurine (3-amino-1-propanesulfonic acid) and N-methyltaurine (2-methylaminoethanesulfonic acid); (b) The anhydrous alkali metal salts of the aminoalkanesulfonic acid of formula (II) include sodium 2-aminoethanesulfonate, sodium N-methyltaurinate, sodium 3-aminopropanesulfonate, sodium 3-(N-methylamino)propanesulfonate, and combinations thereof; and The anhydrous base includes C1-C4 alcoholates, preferably sodium methoxide, potassium methoxide, a methanol solution of potassium methoxide, or combinations thereof.

14. The method according to any one of claims 7 to 13, wherein the mixture comprises: from about 0.90 to about 1.50 moles, preferably from about 0.95 to about 1.20 moles, or more preferably from about 1.00 to about 1.05 moles, of the fatty alkyl ester per mole of the alkali metal salt of the aminoalkanesulfonic acid; and About 1.00 to about 1.50 moles, preferably about 1.02 to about 1.20 moles, and more preferably about 1.05 to about 1.10 moles of said anhydrous base per mole of (a) the aminoalkanesulfonic acid of formula (II); About 0.01 to about 0.5 moles, preferably about 0.02 to about 0.2 moles, and more preferably about 0.05 to about 0.1 moles of said anhydrous base per mole of (b) the anhydrous alkali metal salt of the aminoalkanesulfonic acid of formula (II); or Both.

15. The method according to any one of claims 7 to 14, said method further comprising adding said N-acylaminoalkanesulfonate surfactant to water to form a composition, said composition comprising greater than 20% by weight, preferably greater than 25% by weight, more preferably greater than 30% by weight of said N-acylaminoalkanesulfonate surfactant based on the weight of the composition.

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