Alkoxylate surfactant compositions with low residual alcohol

Abstract

Alcohol ethoxylate compositions may include alcohol ethoxylates prepared from C8 to C16 linear or branched alkyl, include ethoxylate equivalents ranging from 5 to 15, have a polydispersity index (PDI) of 1.02 to 1.07, and synthesized using a calcium-based catalyst; wherein the alcohol ethoxylate composition had a residual alcohol level of less than 0.1 wt%. Methods may include manufacturing an alcohol ethoxylate composition by reacting an alkyl alcohol with ethylene oxide in the presence of a calcium-based catalyst to form an alcohol ethoxylate; wherein the alcohol ethoxylate has a polydispersity index (PDI) of 1.02 to 1.07 and a residual alcohol level of less than 0.1 wt%.

Description

[0001] ALKOXYLATE SURFACTANT COMPOSITIONS WITH LOW RESIDUAL ALCOHOL

[0002] FIELD

[0003] Embodiments relate to the field of nonionic surfactants, specifically to primary alcohol ethoxylate compositions with low residual alcohol levels and methods for their production using calcium-based catalysts.

[0004] BACKGROUND

[0005] Nonionic surfactants are crucial in cleaning formulations, often working alongside anionic surfactants and other components to deliver the desired detergency and performance. The conventional methods for producing nonionic surfactants such as alcohol ethoxylates involve the use of potassium hydroxide (KOH) catalysts, which typically results in a product having a broad Gaussian distribution of molecular weights. In addition, these broad range alkoxylate product mixtures frequently contain significant concentrations of volatile initiator alcohols, which can cause odors and potential safety concerns. Moreover, high molecular weight fractions increase viscosity, do not contribute to end-use performance, and increase material costs. Therefore, there is a need for a solution that improves the detergency of nonionic surfactants and reduces the concentration of volatile byproducts.

[0006] SUMMARY

[0007] In an aspect, embodiments disclosed herein are directed to an alcohol ethoxylate composition containing: an alcohol ethoxylate having the general structure of:

[0008]

[0009] wherein R is a C8 to C16 linear or branched alkyl and n ranges from 5 to 15, and having a polydispersity index (PDI) of 1.02 to 1.07 that is synthesized using a calcium-based catalyst; wherein the alcohol ethoxylate composition has a residual alcohol level of less than 0.1 wt%.

[0010] In another aspect, embodiments disclosed herein are directed to a method of manufacturing an alcohol ethoxylate composition, the method including: reacting an alkyl alcohol with ethylene oxide in the presence of a calcium-based catalyst to form an alcohol ethoxylate; wherein the alcohol ethoxylate has a polydispersity index (PDI) of 1.02 to 1.07 and a residual alcohol level of less than 0.1 wt%.

[0011] DETAILED DESCRIPTIONEmbodiments relate to alcohol ethoxylate compositions and methods of production of alcohol ethoxylates having narrow range molecular weight distributions and low residual alcohol levels. Methods disclosed herein include production of alcohol ethoxylates from the reaction of linear or branched alkyl alcohol and ethylene oxide in the presence of a catalyst composition containing one or more calcium-based catalysts. Narrow range alcohol ethoxylates described herein may exhibit enhanced detergency performance when incorporated in surfactant compositions, such as detergents and cleaning formulations.

[0012] Alcohol ethoxylates disclosed herein are produced by adding ethylene oxide (EO) onto an alkyl alcohol starter compounds in the presence of a catalyst composition containing one or more calcium-based catalysts. Alkyl alcohol starting compounds may be linear or branched, primary C6 to C18 alcohols, such as hexanol, octanol, nonanol, decanol, 2-ethylhexanol, 2-propylheptanol, C8 to CIO linear alcohol mixtures, tridecanol, isotridcanol, and the like. Alcohol ethoxylates compositions may have the general structure of:

[0013]

[0014] where R is a C8 to C16 linear or branched alkyl and n ranges from 5 to 15, or is a single value within the range. In some cases, the alcohol ethoxylate may have an R prepared from a mixture of CIO to C16 alcohols, or C12 to C16 alcohols.

[0015] Catalyst compositions may include one or more solid calcium carboxylates prepared from fatty acids, which increase the solubility of calcium ions in solution, enabling the formation of activated catalytic species for the formation of alkoxylates and controlling the polydispersity of the resulting product. Solid calcium carboxylates may have a molar ratio of calcium to carboxylate (e.g., fatty acid) of 1 :2 or more, such as in a range of 1 :2 to 1 :6, or 1 :2 to 1 :4.

[0016] Calcium carboxylates may have a general structure of: RCOO-Ca-OOCR’, where R and R’ are, independently, saturated or unsaturated C4 to C22 fatty acids. Suitable fatty acids for generating calcium carboxylates may include, for example, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, and behenic acid. Unsaturated fatty acids include palmitoleic, oleic, linoleic, linolenic acids, and the like. In some cases, the calcium carboxylate may be calcium stearate.

[0017] Catalyst compositions may include one or more calcium carboxylates at a percent by weight (wt%) ranging from 35 wt% to 80 wt%, or 40 wt% to 80 wt%.Catalyst compositions may include one or more inorganic acids that are added to activate the calcium carboxylate component. Inorganic acids may include, for example, sulfuric acid, phosphoric acid, nitric acid, and the like. Catalyst compositions may include a percent by mole (mol%) of inorganic acid with respect to the calcium carboxylate of 50 mol% or more, such as in a range of 50 mol% to 90 mol %, or 50 mol% to 80 mol%.

[0018] Catalyst compositions may include one or more inorganic acids at a percent by weight (wt%) ranging from 35 wt% to 80 wt%, or 40 wt% to 80 wt%.

[0019] Catalyst compositions may include one or more inert solvents, where an inert solvent lacks functional groups (e.g. amines, thiols, etc.) capable of reacting in an alkoxylation reaction. Suitable inert solvents may include, for example, toluene, xylene, benzene, cyclohexane, hexane, dimethyl sulfoxide, ketone or ether solvents such as diglyme, triglyme, 1,4-dioxane, diethyl ether, tetrahydrofuran, 1,2-dimethoxyethane. and the like, dimethylformamide, N-methylpyrrolidone, 1,2-dichloroethane, chloroform, carbon tetrachloride, and the like.

[0020] Catalysts may include an inert solvent at a percent by weight (wt%) ranging from 5 wt% to 80 wt%, or 5 wt% to 75 wt%.

[0021] The catalyst composition may be in the form of a powder, a slurry or solvent solution that is added to a reactor for alkoxylation reactions. In some cases, the catalyst composition may be treated with a volatile wash solvent to precipitate a solid catalyst composition that can be removed by filtration or other suitable means. Suitable wash solvents may include dimethyl ether, diethyl ether, dimethoxy ethane, diethoxymethane, dibutylether, isopropyl ether, and the like. In some cases, solid catalyst compositions may be dried to remove trace solvents and other volatiles.

[0022] In one method, alcohol ethoxylates may be generated by combining the catalyst composition with the alcohol to be ethoxylated (e.g., a C8-C16 alcohol mixture). The catalyst composition and the alcohol(s) are heated to the reaction temperature, such as between 100 °C to 180 °C. Ethylene oxide (EO) and optional additional alkylene oxides (e.g., propylene oxide, butylene oxide) are introduced under controlled conditions (e.g., 4 atm to 7 atm), to react with the alcohol, forming the ethoxylated product. After the desired degree of ethoxylation is achieved, the reaction mixture is neutralized, for example with acetic acid, and optionally filtered to remove the catalyst and any byproducts. The resulting narrow range alcohol ethoxylate product is then recovered.

[0023] Alcohol ethoxylate compositions disclosed herein may have a residual alkyl alcohol concentration of 0.15 wt% or less, 0.1 wt% or less, such as in a range of 0.001 wt% to 0.15 wt%.Alcohol ethoxylate compositions disclosed herein may contain average 5 to 15, or 5 to 10 moles of EO on each mole of alcohol initiator. For example, alcohol ethoxylates compositions may have the general structure of:

[0024]

[0025] where R is a C8 to Cl 6 (including all subranges such as C12 to C16) linear or branched alkyl and n is a range from 4 to 15, 5 to 10, 7 to 9, 8 to 10, and the like. In some cases, n may be an integer value, where the integer indicates that the primary product in the mixture (i.e., >20 wt%) is an alcohol ethoxylate with the specified integer.

[0026] Alcohol ethoxylate compositions disclosed herein may have a polydispersity index (PDI) ranging from 1.01 to 1.10, or 1.02 to 1.07.

[0027] Alcohol ethoxylates described herein may be included in a surfactant and / or detergent composition with one or more surfactants, including anionic surfactants. Alcohol ethoxylate compositions disclosed herein may have one or more surfactants present at a percent by weight (wt%) from 40 wt% to 95 wt%, 45 wt% to 95 wt%, or 50 wt% to 90 wt%. Additional surfactants may include anionic surfactants, such as sulfonates or sulfonic acid salts such as those having a formula R3-SO3M wherein R3 represents a hydrocarbyl group selected from the group consisting of straight or branched alkyl radicals having from 12 to 24 carbon atoms; and alkylphenyl radicals having from 9 to 15 carbon atoms in the alkyl group; and M is hydrogen or a salt-forming cation selected from the group consisting of Na, K, NH4, and mono-, di-, and trialkanol amines having 2 to 3 carbon atoms in the alkanol groups. Additionally, suitable anionic surfactant may include one or more salts (e.g., sodium, potassium, ammonium, and substituted ammonium salts such as mono-, di- and triethanolamine salts) of anionic carboxylates and sarcosinates. Exemplary anionic sulfonate surfactants can include salts of C5-C20 linear alkylbenzene sulfonates, such as dodecylbenzene sulfonic acid (DDBSA), alkyl ester sulfonates, C6-C22 primary or secondary alkane sulfonates, C6 to C24 olefin sulfonates, sulfonated polycarboxylic acids, alkyl glycerol sulfonates, fatty acyl glycerol sulfonates, fatty oleyl glycerol sulfonates, and any mixtures thereof. Exemplary anionic sulfates can include linear and / or branched primary and secondary alkyl sulfates, alkyl ethoxysulfates, fatty oleoyl glycerol sulfates, alkyl phenol ethylene oxide ether sulfates, and sulfates of alkylpolysaccharides, such as alkylpolyglucoside sulfates. Exemplary alkyl sulfates can include linear and branched primary CIO to C18 alkyl sulfates. Exemplary alkylethoxy sulfate surfactants can include CIO to C18 alkyl sulfates that have been ethoxylated with from 0.5 to 20 moles of ethylene oxide per molecule. Exemplary anionic carboxylates can include alkyl ethoxy carboxylates, and alkyl polyethoxy polycarboxylates.

[0028] Other optional components in surfactant compositions may include alkaline sources viscosity or rheology modifiers, co-builders (e.g., organophosphonates) chelating agents, neutralizing agents, perfumes, and the like.

[0029] The use of calcium carboxylate-based catalysts results in a product with a narrow ethoxylate distribution and extremely low residual alcohol levels, which are not achieved by conventional KOH-catalyzed processes or other calcium-based catalysts. Narrow range alcohol ethoxylates exhibit improved detergency and performance in cleaning formulations, making them highly suitable for use in home care and industrial & institutional applications.

[0030] Applications for nonionic surfactants include a wide variety of formulations and products used as cleaners, detergents, hard surface cleaning formulations, reactive diluents in casting, encapsulation, flooring, potting, adhesives, laminates, reinforced plastics, filament windings, coatings, wetting agents, rinse aids, de- or anti-foam agents, spray cleaning agents, emulsifiers for herbicides and pesticides, metal cleaning agents, suspension aids and emulsifiers for paints and coatings, and the like.

[0031] While formulation components and properties have been disclosed individually, it is envisioned that component elements may be included, excluded, or combined in any manner or subcombination utilizing any of the above concentration ranges and nested subranges therein. Further, that the recited formulation properties may be similarly achieved through various combinations of the recited components within the recited ranges.

[0032] EXAMPLES

[0033] The following examples are provided to illustrate the embodiments of the invention, but are not intended to limit the scope thereof. Table 1 provides the materials used in the following examples.

[0034]

[0035] Example 1 : Component Synthesis

[0036] Synthesis of Ca-Slurry Catalyst: The Ca-slurry catalyst was prepared according to the procedure in U.S. Patent No. 4,754,075 with a C12-C16 alcohol mixture. Initially, calcium oxide or hydroxide was solubilized in an activating agent resulting in an alkaline slurry of titratable alkalinity. To this an exchange agent of higher boiling point is added and the free activator is removed by distillation. An oxy-acid, preferably sulfuric acid, is also added to partially neutralize the titratable alkalinity. The resulting slurry is used directly as the ethoxylation catalyst slurry.

[0037] Synthesis of Ca-Stearate Catalyst: The calcium stearate sulfate catalyst was prepared by reaction of calcium stearate with 0.5 equivalents of sulfuric acid in diglyme as the solvent. The resulting materials were washed with diethyl ether, dried at room temperature and used in the ethoxylation reaction.

[0038] Synthesis of C12-C16+9EO by Calcium Stearate Catalysis (IE1): Initially, 6.2 g of calcium stearate powder catalyst was mixed with 1000 g of C12-C16 alcohol initiator and flashed at 80°C for 1 hour in a 2 L flask using a rotovap. The water content in the starter mixture was reduced to less than 100 ppm. The starter was then charged to a 2 gallon reactor and inerted with nitrogen. The reactor was heated to 145 °C, and ethylene oxide was fed at a rate of 10 g / min. After the oxide feed was completed, the reactor was maintained at 145 °C for digestion. Once digestion was completed, the reactor was cooled to 60°C. A sample was collected to measure the hydroxyl value (%OH) and confirm that the target 9 mol EO was reached. The product was finished with glacial acetic acid at 60°C to achieve a final pH of around 7. The product was then drained and stored for further analysis.

[0039] Synthesis of C12-C16+9EO by Calcium Slurry Catalysis (CE2): This material was prepared using a 2-gallon reactor. Initially, 44.6 g of calcium catalyst slurry was mixed with 1000 g of C12-C16 initiator and flashed at 80°C for 1 hour in a 2 L flask using a rotovap. The water content in the starter mixture was reduced to less than 100 ppm. The starter was then charged to a 2 gallon reactor and inerted with nitrogen.. The reactor was heated to 145 °C, and ethylene oxide was fed at a rate of 4 g / min and the reactor was maintained at 145°C for digestion. Once completed, the reactor was cooled to 60°C. A sample was collected to measure the hydroxyl value (%OH) and confirm that the target 9 mol EO was reached. The product was finished with glacial acetic acid at 60°C to achieve a final pH of around 7. The product was then drained and stored for further analysis.

[0040] Example 2: Component Property testingAlcohol ethoxylates where characterized using the following metrics.

[0041] Hydroxyl value was measured according to ASTM D4274.

[0042] EO oligomer distribution was characterized using LC-ELSD. The LC system used for EO oligomer distribution measurements is shown in Table 2 and the instrument conditions used are given in Tables 3 and 4.

[0043]

[0044]

[0045]

[0046] Sample Preparation

[0047] LC samples were prepared by dissolving 100 mg of alcohol ethoxylate in 10 mL of acetonitrile for a final concentration of 10 mg / mL. After the addition of acetonitrile, samples were vortexed for 30 seconds and then aliquoted to 2mL sample vials.

[0048] Residual Alcohol by Gas Chromatography: Residual alcohol level was measured by dilution of the ethoxylate sample to 10wt% in methanol and dilution of the alcohol initiator tolwt% in Methanol. Samples were injected according to the following GC method in Table 5. The areas of Cl 2, Cl 4, C16 alcohols were integrated and residual alcohol quantified using Eq. I.

[0049] " ">

[0050]

[0051] 1 Table 5: System for testing residual alcohol concentration :

[0052] i

[0053] i

[0054]

[0055] Surface Tension and critical micelle concentration: Surface Tension was measured on lwt% active solutions in water using the Wilhelmy plate method and Kruss Processor Tensiometer K-100 instrument. CMC values were obtained on the same instrument with a 0.1 wt% stock solution.

[0056] Cloud Point: Cloud point of the samples was measured using ASTM D2024.

[0057] Ross-Miles Foam: Ross-Miles Foam test was conducted as described by ASTM method D1173.

[0058] Pour Point: Pour point was measured on a MPP 5Gs pour point instrument according to manufacturer specification.

[0059] Contact Angle: Contact angle measurements were performed at ambient temperature utilizing Kruss DSA-100 Drop Shape Analyzer on parafilm and Teflon tape that are flatted on glass slide.Example 3: Summary of Surfactant Properties

[0060] The surfactant properties of the tested alcohol ethoxylates are summarized in Table 6.

[0061]

[0062] Example 4: Summary of Structural / Compositional Properties

[0063] The structural and compositional properties of the tested alcohol ethoxylates were summarized in Tables 7 and 8.

[0064]

[0065]

[0066]

[0067] These examples demonstrate the synthesis, testing, and properties of the primary alcohol ethoxylates produced using calcium-based catalysts. The results highlight the low residual alcohol levels of the ethoxylates. CE1, CE2, and IE1 all have the same hydroxyl value indicating that the molecular weight of the samples is roughly equivalent. LC-ELSD shows that CE1 has a broad distribution of EO oligomers, while CE2 and IE1 have similar distributions.

[0068] Example 4: Laundry Unit Dose Formulation

[0069] The alcohol ethoxylates were tested for their performance in laundry formulations, including primary cleaning and anti-redeposition performance. The narrow range (NRE) primary alcohol ethoxylates (PAE) were tested in both unit dose and liquid laundry (HDL) formulations. The laundry unit dose formulation is shown in Table 9, and laundry HDL formulations are shown in Table 10.

[0070]

[0071]

[0072] Example 5: Primary Cleaning of Sebum StainPrimary cleaning testing for sebum stain was conducted using a Tergitometer with six parallel, 2L canisters, each filled with IL of 120 ppm Ca:Mg 3:1 hardness adjusted water. The wash temperature was set to 72°F. The test detergent formulations for unit dose and liquid laundry (HDL) with the recipes given in the ICD were added at a dosage level of 0.3 g / L and 0.65 g / L, respectively. The Tergitometer spindle speed was adjusted to 85 rpm. Four 5 cm x 5 cm testing fabrics of PC-S-94 dust sebum swatches from Testfabrics were added into each canister and washed for 30 minutes. The fabrics were then removed, and the wash solutions were drained. Hardness adjusted water was added to the canisters, and the washed fabrics were added back to the canisters and rinsed for 3 minutes. The fabrics were then removed and dried in a dryer on the "warm" setting for 60 minutes.

[0073] The L*, a*, and b* values of the stained fabrics were measured pre-wash (US) and postwash (WS) with a Mach 5+ spectrophotometer from Colour Consult. The L*, a*, and b* values for the unwashed, unstained polycotton fabric (UF) were measured to use in the Soil Removal Index (SRI) calculations.

[0074] The L*, a* and b* values of the stained fabrics were measured pre (US) and post wash (WS) with a Mach 5+ spectrophotometer from Colour Consult. The L*, a* and b* values for the unwashed, unstained polycotton fabric (UF) was measured to use in the SRI calculations as follows:

[0075]

[0076] where US = Unwashed stain area, UF = Unwashed (unstained) fabric area, WS = Washed stain area.

[0077]

[0078] > = Delta-E color difference between the unwashed stain and the unwashed fabric, and ^E^ws-UFy = Delta-E color difference between the washed stain and the unwashed fabric. The value delta E* is calculated as: AE* = (AL2+ Aa2+ Ab2)°5

[0079] This test was repeated twice and the data from both tests were combined to compare the performance of the detergents with the different testing surfactants.

[0080] The primary cleaning performance of the laundry formulations was evaluated, and the results are summarized in Table 11. Connecting letters reports are provided. Levels that share, or are connected by, the same letter do not differ statistically. Levels that are not connected by a common letter do differ statistically.

[0081]

[0082] The results showed that the ethoxylates synthesized using the calcium stearate catalyst (IE1) exhibited improved sebum soil removal compared to those synthesized using the calcium slurry catalyst (CE1 and CE2). The ethoxylates were also tested for their ability to prevent soil redeposition on various fabric types. The results indicated that the ethoxylates synthesized using the calcium stearate catalyst (IE1) performed comparably to those synthesized using the calcium slurry catalyst (CE1 and CE2), with CE2 showing more graying.

[0083] Example 6: Anti-Redeposition Testing

[0084] Anti-redeposition tests were performed in a Testfabrics Tergitometer with six pots in parallel at room temperature. The water hardness was adjusted to 300 ppm with a 2: 1 Ca:Mg molar ratio. Detergent formulations were prepared according to the recipe provided in the ICD. The fabric types evaluated were Cotton 400, Cotton Interlock, Cotton Terry, Nylon, Polyester 777H, and Polycotton (65:35 Polyester / Cotton Blend). Each pot was loaded with IL of hardness adjusted water, 0.3 g of test detergent, 2.5 g dust sebum, and 0.63 g Redart clay. The fabrics were washed for 12 minutes and rinsed for 3 minutes for five cycles at room temperature, with two cloths of each fabric type in each pot. The fabrics were then dried in a dryer on the "warm" setting for 60 minutes. Pre- and post-readings of the testing fabrics were taken with a Mach 5+ spectrophotometer from Colour Consult. Whiteness index values were calculated using the formula: WI = (3.388Z) - (2.75Y). Larger values for WI indicate less graying and better performance. The whiteness index values of stripped, untested fabrics were included for reference.

[0085]

[0086]

[0087]

[0088] These examples demonstrate the synthesis, testing, and properties of the primary alcohol ethoxylates produced using calcium-based catalysts. The results highlight the improved performance and low residual alcohol levels of the ethoxylates, making them highly suitable for use in cleaning formulations. Despite the structural similarities, it was surprisingly found that the residual alcohol level of IE1 is significantly reduced compared to both comparative examples and is below the residual alcohol that has been reported in the prior art for an ethoxylate product. Compositions comprising IE1 also result in functional benefits in laundry testing. Primary cleaning results show significantly improved sebum soil removal with the HDL formulation that contains IE1 vs. HDL formulations with CE1 and CE2.

[0089] While the foregoing is directed to exemplary embodiments, other and further embodiments may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.

Claims

Claims1. An alcohol ethoxylate composition comprising:an alcohol ethoxylate having the general structure of:wherein R is a C8 to C16 linear or branched alkyl and n ranges from 5 to 15, and having a polydispersity index (PDI) of 1.02 to 1.07 that is synthesized using a calcium-based catalyst;wherein the alcohol ethoxylate composition had a residual alcohol level of less than 0.1 wt%.

2. The composition of claim 1 , wherein the calcium-based catalyst is a calcium carboxylate catalyst.

3. The composition of claim 1, wherein the calcium-based catalyst is a calcium stearate sulfate catalyst.

4. The composition of claim 1 , wherein n ranges from 5 to 10.

5. The composition of claim 1, wherein n ranges from 7 to 9.

6. The composition of claim 1, wherein n ranges from 8 to 10.

7. The composition of claim 1, wherein n is 9.

8. The composition of claim 1, further comprising one or more anionic surfactants.

9. Use of the composition of claim 1 in a detergent formulation.

10. A method of manufacturing an alcohol ethoxylate composition, the method comprising:reacting an alkyl alcohol with ethylene oxide in the presence of a calcium-based catalyst to form an alcohol ethoxylate;wherein the alcohol ethoxylate has a poly dispersity index (PDI) of 1.02 to 1.07 and a residual alcohol level of less than 0.1 wt%.

11. The method of claim 10, wherein the calcium-based catalyst is a calcium stearate catalyst.

Images