ITAKONATE SURFACTANT

Abstract

The invention provides an itaconate surfactant having the following formula (I) (I) where R1 is selected from the aliphatic hydrocarbyl group having 4 to 22 carbon atoms; R2 is selected from the hydrogen and aliphatic hydrocarbyl groups having 1 to 4 carbon atoms; and n is an integer ranging from 8 to 20. The surfactant of the invention is safe for skin and the environment yet can provide comparable performance to “traditional” anionic and anionic / nonionic surfactant systems, especially on stubborn stains.

Description

Description ITAKONATE SURFACTANT Invention Engineering Field The present invention relates to itaconate surfactants and their applications. Background of the Invention Anionic sulfonates or sulfate surfactants, such as linear alkylbenzene sulfonates (LAS) or primary alcohol sulfates (PAS), are often used as basic detergent active ingredients in household detergent compositions due to their excellent cleaning properties. They are often used in conjunction with nonionic surfactants such as ethoxylated alcohols, which provide enhanced detergency on hydrophobic soils. The anionic and anionic / nonionic surfactant systems mentioned above are robust and highly effective on a wide range of impurities and under a wide range of conditions, such as temperature and water hardness. However, anionic surfactants are not known for their gentleness on skin. Furthermore, their production still relies heavily on non-renewable resources, such as petroleum, natural gas, and coal. The underlying problem of the present invention is to provide a surfactant and surfactant system that is safe for the skin and the environment yet can provide comparable performance to traditional anionic and anionic / nonionic surfactant systems, particularly on stubborn stains. Such stains include, for example, polyphenolic-based stains such as cherry juice, blueberry juice, and red wine, along with tea, coffee, and chocolate pudding. This problem is solved by providing a surfactant according to the present invention. Brief Description of the Invention The surfactant according to the present invention is an itaconate surfactant having the following formula (I) where R1 is selected from the aliphatic hydrocarbyl group having 4 to 22 carbon atoms; R is selected from the hydrogen and aliphatic hydrocarbyl groups having 1 to 4 carbon atoms; and n is an integer ranging from 8 to 20. The invention also provides a process for preparing an itaconate surfactant of formula (I), the process comprising the following steps: (i) reacting itaconic anhydride with an alcohol of general formula R1OH (where R1is as defined above) to produce an itaconate ester; and (ii) oxylating the itaconate ester to produce an itaconate surfactant of formula (I). Complete Description of the Invention In formula (I) above, R1 is preferably selected from a saturated or unsaturated, linear or branched hydrocarbyl group having from 8 to 20 carbon atoms and from 0 to 3 double bonds. More preferably, R1 is selected from a linear alkyl or linear alkenyl group containing from 12 to 18 carbon atoms and 0 or 1 double bonds. Preferred examples of such groups include lauryl, myristyl, palmityl, cetyl, oleyl and stearyl and mixtures thereof (which may be derived, as a rule, from natural fats and / or optionally hydrogenated natural oils such as coconut oil, palm kernel oil or tallow). In formula (I) above, R2 is preferably methyl, ethyl, or n-butyl and methyl is preferred. In formula (I) above, n is preferred to range from 8 to 10 and is preferably 8 or 9. The preferred process for preparing itaconate surfactant with formula (I) includes the following steps: (i) reacting itaconic anhydride with an alcohol of general formula R1OH (where R1 is as defined above) to produce an itaconic ester; (iia) reacting polyethylene glycol of formula R2O(CH2CH2O)n-CH2CH2OH (where R2and n are as defined above) with a sulfonyl halide, to form an intermediate; and (iib) reacting the itaconate ester obtained in (i) with the intermediate obtained in (iia) to produce an itaconate surfactant of formula (I). The sulfonyl halide in (iia) may suitably be selected from aromatic sulfonyl halides wherein the aromatic group may be a benzene or naphthalene nucleus having 0, 1 or 2 substituents (each of which is independently selected from a halogen atom and a C1-4 alkyl group), with the bond to the sulfonyl group extending from the nucleus. The aromatic group is preferably a benzene nucleus that may be substituted with a chlorine atom or a methyl group, preferably in the 4-position. Examples of preferred aromatic sulfonyl halides include benzenesulfonyl chloride, 4-chlorobenzenesulfonyl chloride and especially 4-toluenesulfonyl chloride. Other sulfonyl halides that may be used include C1-4 alkane sulfonyl halides such as methane- and ethane-sulfonyl chlorides and bromides. The itaconate surfactant of the invention is useful in a variety of end-use applications including general purpose detergents, including laundry applications and hard surface cleaners. The invention thus includes a detergent composition comprising the itaconate surfactant of the invention, a cleaning method using the detergent composition comprising the itaconate surfactant of the invention; and the use of the itaconate surfactant of the invention as a detergent. In laundry applications, the itaconate surfactant of the invention will typically be formulated together with other ingredients into a laundry detergent composition. The invention thus includes a laundry detergent composition comprising the itaconate surfactant of the invention, a method of cleaning laundry using the laundry detergent composition comprising the itaconate surfactant of the invention; and the use of the itaconate surfactant of the invention as a detergent in laundry washing. The term “laundry detergent composition” in the context of the present invention refers to a formulated composition intended for and capable of wetting and cleaning domestic laundry such as clothing, linens and other household textiles. The term “linen” is often used to describe certain types of laundry articles including bed sheets, pillow cases, towels, tablecloths, table napkins and uniforms. Textiles may include woven fabrics, non-woven fabrics, and knitted fabrics; and may include natural or synthetic fibers such as silk fibers, linen fibers, cotton fibers, polyester fibers, polyamide fibers such as nylon, acrylic fibers, acetate fibers, and blends thereof including blends of cotton and polyester. Examples of laundry detergent compositions include heavy-duty detergents for use in the wash cycle of an automatic washing machine, as well as detergents for delicate washing and color care such as those suitable for washing delicate garments (e.g., those made of silk or wool) by hand or in the wash cycle of an automatic washing machine. The laundry detergent composition according to the invention may suitably be in liquid or particulate form, or a mixture thereof. The term “particulate” in the context of the present invention refers to free-flowing or compact solid forms such as powders, granules, pellets, flakes, rods, briquettes or tablets. One preferred form for the particulate laundry detergent composition according to the invention is a free-flowing solid powder, with a loose (unpacked) bulk density generally ranging from about 200g / l to about 1,300g / l, preferably from about 400g / l to about 1,000g / l, more preferably from about 500g / l to about 900g / l. The most preferred laundry detergent composition according to the invention is in liquid form. The term liquid in the context of the present invention indicates that the continuous phase or major portion of the composition is liquid and that the composition is flowable at 15°C and above. Accordingly, the term liquid may include emulsions, suspensions, and compositions having a stiffer consistency but capable of flowing, known as gels or pastes. The viscosity of the composition may suitably range from about 200 to about 10,000 mPa.s at 25°C at a shear rate of 21 s-1. This shear rate is the shear rate normally imparted to the liquid when poured from a bottle. Pourable liquid compositions generally have a viscosity of from 200 to 2,500 mPa.s, preferably from 200 to 1,500 mPa.s. The liquid composition is a pourable gel generally having a viscosity of from 1,500 mPa.s to 6,000 mPa.s, preferably from 1,500 mPa.s to 2,000 mPa.s. The itaconate surfactant of the invention will generally be included in the laundry detergent composition according to the invention at a concentration of 0.5 to 35% (on a weight basis of the total weight of the composition). Laundry detergent compositions according to the invention will generally include other surfactants (in addition to the itaconate surfactant of the invention). The choice of surfactant, and the total amount present, will depend on the intended use. For example, different surfactant systems may be selected for hand-washing products and for products intended for use in different types of automatic washing machines. In compositions for machine-washing fabrics, the total surfactant amount is from 5 to 40%, such that 15 to 35% (by weight based on the total weight of the composition) is generally appropriate. Higher levels may be used in compositions for hand-washing fabrics, such as up to 60% (by weight based on the total weight of the composition). Other surfactants (other than the itaconate surfactants of the invention) may suitably be selected from non-soap anionic surfactants, which are typically salts of organic sulfates and sulfonates having alkyl radicals containing from about 8 to about 22 carbon atoms, the term alkyl being used to include the alkyl portion of the higher-order acyl radical. Examples of such materials include alkyl sulfates, alkyl ether sulfates, alkaryl sulfonates, alpha-olefin sulfonates and mixtures thereof. The alkyl radicals preferably contain from 10 to 18 carbon atoms and may be unsaturated. The alkyl ether sulfates may contain from one to ten ethylene oxide or propylene oxide units per molecule, and preferably contain from one to three ethylene oxide units per molecule. The counterions for anionic surfactants are generally alkali metals such as sodium or potassium; or ammoniacal counterions such as monoethanolamine, (MEA) diethanolamine (DEA) or triethanolamine (TEA). A mixture of any of the ingredients described above can also be used. In the laundry detergent composition according to the invention, the total content of non-soap anionic surfactants can suitably range from 5 to 30% (on a weight basis of the total weight of the composition). Other surfactants (other than the itaconate surfactants of the invention) may also be selected from nonionic surfactants, which are typically aliphatic primary linear alcohol ethoxylates Cg to Cgg, preferably Cgg to Cgg, with an average of from 3 to 20, preferably from 5 to 10 moles of ethylene oxide per mole of alcohol. Also suitable are nonionic surfactants derived from sugars such as alkyl polyglycosides corresponding to the general formula RiO(RgO) b (Z)a wherein R2 is a monovalent hydrocarbyl group having from 6 to 30 carbon atoms; R2 is a divalent alkylene radical having from 2 to 4 carbon atoms; Z is a saccharide residue (preferably glucose) having 5 or 6 carbon atoms; b is a number having a value from 0 to 12 (preferably 0) and a is a number having a value from 1 to 6. Good results have been obtained with polysorbate-based nonionic surfactants such as ethoxylates of sorbitol esters of fatty acids having the following core structure: 0ROR i \--OR where each R is independently chosen from a hydrogen or PEG chain with or without a fatty ester end cap. Typical materials have the following structures: where w+x+y+z ranges from 3 to 30 and R is a monovalent hydrocarbyl group having from 6 to 30 carbon atoms. Preferably w+x+y+z is 4, 5, or 20; and R is selected from a linear alkyl or linear alkenyl group containing from 12 to 18 carbon atoms and 0 or 1 double bond, such as lauryl, myristyl, palmityl, cetyl, oleyl and stearyl and mixtures thereof (as may be derived, as a rule, from natural fats and / or optionally hydrogenated natural oils such as coconut oil, palm kernel oil or tallow). Examples of such materials include polyoxyethylene (20) sorbitan monolaurate, polyoxyethylene (20) sorbitan monopalmitate, polyoxyethylene (20) sorbitan monostearate, polyoxyethylene (20) sorbitan monooleate, polyoxyethylene (4) sorbitan monolaurate, polyoxyethylene (4) sorbitan monostearate, and polyoxyethylene (5) sorbitan monooleate. A mixture of any of the ingredients described above can also be used. In the laundry detergent composition according to the invention, the total content of nonionic surfactants (other than the itaconate surfactant of the invention) may suitably range from 0 to 25% (on a weight basis of the total weight of the composition). The liquid laundry detergent composition according to the invention may generally contain from 5 to 95%, preferably from 10 to 90%, more preferably from 15 to 85% water (on a weight-based basis of the total weight of the composition). The composition may also incorporate from 0.1 to 15% (on a weight-based basis of the total weight of the composition) of a non-aqueous carrier such as a hydrotrope, a co-solvent and a phase stabilizer. The laundry detergent composition according to the invention may contain one or more building materials. The building materials enhance or maintain the cleaning efficiency of the surfactant, primarily by reducing water hardness. This is accomplished through sequestration or chelation (retaining hardness minerals in solution), through precipitation (forming insoluble substances), or through ion exchange (exchanging electrically charged particles). The building materials for use in the invention may be organic or inorganic building materials, or mixtures thereof. Non-phosphate building materials are preferred. Preferred inorganic non-phosphate building blocks for use in the invention may be selected from zeolites, sodium carbonate, δ-sodium disilicate and mixtures thereof. Preferred organic non-phosphate building materials for the building materials used in the invention may be selected from polycarboxylates (e.g. citrates) in the form of acids and / or salts and mixtures thereof. A mixture of any of the ingredients described above can also be used. The total content of the building material, when included, may range from about 0.1 to about 80%, preferably from about 0.5 to about 50% (on a weight basis of the total weight of the composition). The particulate laundry detergent composition of the invention may include one or more fillers to assist in providing desired density and bulkiness to the composition. Preferred fillers for use in the invention include alkali metal sulfates and chlorides (preferably sodium and / or potassium) and mixtures thereof, with sodium sulfate and / or sodium chloride being most preferred. The fillers, if included, may be present in a total amount ranging from about 1 to about 80%, preferably from about 5 to about 50% (on a weight-based basis of the total weight of the composition). The laundry detergent composition according to the invention may include one or more polymeric cleaning boosters such as antiredeposition polymers, soil-releasing polymers and mixtures thereof. Antiredeposition polymers stabilize dirt in the washing solution thereby preventing redeposition of the dirt. Preferred materials are ethoxylated polyethyleneimines, with an average degree of ethoxylation of from 10 to 30, preferably from 15 to 25 ethoxy groups per ethoxylated nitrogen atom in the polyethyleneimine backbone. Other suitable types of antiredeposition polymers for use in the invention include cellulose esters and ethers, for example, sodium carboxymethyl cellulose. A mixture of any of the ingredients described above can also be used. The total content of the anti-redeposition polymer, if included, may range from 0.05 to 6%, preferably from 0.1 to 5% (on a weight basis of the total weight of the composition). Soil release polymers (SRPs) help improve the removal of soil from fabrics by modifying the fabric surface during washing. The adsorption of SRPs on the fabric surface is driven by the affinity between the chemical structure of the SRP and the target fiber. Preferred SRPs for use in the invention include copolyesters formed by the condensation of terephthalic acid esters and diols, preferably 1,2 propanediol, and further comprise end caps formed from alkyl group-capped alkylene oxide repeating units. A mixture of any of the ingredients described above can also be used. The total SRP content, if included, may range from 0.1 to 10%, preferably from 0.3 to 7%, more preferably from 0.5 to 5% (on a weight-based basis of the total weight of the composition). The laundry detergent compositions according to the invention may in some cases contain one or more fatty acids and / or salts thereof. Preferred examples of such ingredients include saturated C12-18 fatty acids such as lauric acid, myristic acid, palmitic acid, or stearic acid; and fatty acid mixtures wherein 50 to 100% (by weight based on the total weight of the mixture) comprises saturated C12-18 fatty acids. Such mixtures may typically be derived from natural fats and / or optionally hydrogenated natural oils (such as coconut oil, palm kernel oil, or tallow). The fatty acids may be present in the form of their sodium, potassium, or ammonium salts and / or in the form of soluble salts of organic bases, such as mono-, di-, or triethanolamine. A mixture of any of the ingredients described above can also be used. Fatty acids and / or salts thereof, when included, may be present in amounts ranging from about 0.25 to 5%, preferably from 0.5 to 5%, most preferably from 0.75 to 4% (on a weight basis of the total weight of the composition). For the purposes of formula calculations, in the formulation, fatty acids and / or their salts (as defined above) are not included in the surfactant content or in the building material content. The liquid laundry detergent composition according to the invention may contain one or more rheology modifiers. Examples of such materials include polymeric thickeners, such as hydrophobically modified alkali emulsion (HASE) swelling copolymers; and / or structures that form a network within the composition, such as hydrogenated castor oil, cellulose microfibers, and citrus pulp fibers. The laundry detergent composition according to the invention may contain an effective amount of one or more enzymes selected from the group containing, pectate lyase, protease, amylase, cellulase, lipase, mannanase and mixtures thereof. The enzymes are preferably provided with a suitable enzyme stabilizer. The liquid laundry detergent composition according to the invention preferably has a pH in the range of 5 to 9, more preferably 6 to 8, when measured at a dilution of the composition to 1% (on a weight basis of the total weight of the composition) using demineralized water. The laundry detergent composition of the invention may contain other optional ingredients to enhance performance and / or consumer acceptance. Examples of such ingredients include fragrance oils, foam enhancers, preservatives (e.g., bactericides), antioxidants, sunscreens, anticorrosive agents, colorants, pearlescent and / or opacifying agents, and shadow dyes. Each of these ingredients will be present in an amount effective to achieve its intended purpose. Generally, these optional ingredients are included at amounts up to 5% each (by weight of the total weight of the composition). Packaging and measuring The laundry detergent composition of the invention may be packaged as a unit dose in a water-soluble polymeric film. Alternatively, the detergent composition of the invention may be supplied in a multi-dose plastic container with a top or bottom closure. The dosage may be supplied with the container as part of the closure or as an integrated system. A method for washing a fabric stain using a laundry detergent composition according to the invention includes diluting a quantity of the laundry detergent composition to obtain a washing liquid, and washing the stained fabric with the resulting washing liquid. The appropriate method can be done in a top-loading or front-loading automatic washing machine, or it can be done by hand. In automatic washing machines, a typical laundry detergent composition is placed in a dispenser and from there is dispensed into the machine by the water flow into the machine 5, thus forming a washing liquid. The dosage for a front-loading washing machine (using 10 to 15 liters of water to form the washing liquid) can range from about 10 ml to about 100 ml, preferably about 15 to 75 ml. The dosage for a typical top-loading washing machine (using from 40 to 60 liters of water to form the washing liquid) can be higher, for example 100 ml or more. Lower dosages of detergent (for example 50 ml or less) can be as much as 10 used for hand-washing methods (using about 1 to 10 liters of water to form the washing liquid). A subsequent aqueous rinsing step and dry laundry are preferred. Any water input during any optional flushing step(s) is not included when specifying the washer fluid. Laundry drying can take place in an automatic dryer or in the open air. The invention will now be further explained with reference to the following non-limiting Examples. Example All weight percentages are based on total weight unless otherwise specified. Synthesis of itaconate surfactant with formula (I) according to the invention Step 1 - Synthesis of monolauryl itaconate CHCI □ dry, reflux for 24 o Itaconic anhydride (10g, 76.9 mmol) and lauryl alcohol (17.1g, 92.3 mmol) were dissolved in 100 ml of dry chloroform and refluxed overnight (16 h). The reaction mixture was concentrated with a small amount of chloroform followed by the addition of hexane to produce a white precipitate which was filtered. The white precipitate was collected and dried in vacuo. Step 2 - Synthesis of PEG-tosylate: P EfriSi-OTs NaOH (2.2g, 54.5 mmol) was dissolved in a small amount of water (23ml) and added to a solution of PEG-500 (20g, 36.6 mmol) in THE (100 ml). The reaction mixture was cooled to 0°C followed by the slow addition of tosyl chloride (10.4g, 54.5 mmol) and the reaction mixture was allowed to come to room temperature. The reaction mixture was stirred at room temperature for 24 hours followed by the addition of water (20 ml). The reaction mixture was stirred for 30 minutes and the THE layer was collected and passed through anhydrous sodium sulfate. The resulting liquid was dissolved in diethyl ether to remove excess p-toluene sulfonic acid (a white solid precipitated); the ether layer was evaporated to dryness to obtain the pure product. Step 3 - Synthesis of C12-Ita-PEG-550 DMSOserdesaasi Monolauryl itaconate from Step 1 (5.4g, 17.3mmol), PEG-550tosylate from Step 2 (11.1g, 15.8mmol), NaHCO3(2.6g, 31.6mmol) and KI (catalytic amount) were dissolved in a small amount of DMSO (5ml) and stirred at 40oC for 2 days. C16-Ita-PEG-550 can be prepared by following steps 1 to 3 above with the substitution of cetyl alcohol for lauryl alcohol in Step 1. Efficacy in stain removal of itaconate surfactant with formula (I) according to the invention. The itaconate surfactant of formula (I) according to the invention was evaluated for its stain removal performance against various standard stains (baby food, grass and mud, tomato pulp, red wine, garden soil, beef fat, chocolate ice cream and black tea) on cotton and polyester fabrics. A series of surfactant mixtures were prepared with ingredients and ratios as shown below in Table 1: Table 1 Ingredients % by weight (active ingredients) 20 Formulation Example A Example B Example 1 Example 2 LAS acid 5 Alcohol ethoxylate 5 SLES 5 25 Polyoxyethylene (20) sorbitan monolaurate 7.5 5 5 Polyoxyethylene (4) sorbitan monolaurate 7.5 5 5 C12-Ita-PEG-550 5 C16-Ita-PEG-550 5 30 Sufficient water to 10 0 Examples A and B are Comparative Examples (not according to the invention). Examples 1 and 2 are Examples according to the invention. Polyester test fabrics and cotton test fabrics stained with the above standard stains were washed with the surfactant mixtures shown in Table 1. The degree of stain removal was measured by performing diffuse reflectance measurements using a spectrometer, and expressed as the Stain Removal Index (SRI), defined as: SRI = 100 - ΔΕ, where ΔΕ is the color difference of the stained test fabric compared to the unstained test fabric. A higher SRI value indicates a cleaner fabric. The results are shown in Table 2. Table 2 AB test formulation 1 2 Stain removal index (SRI) Stain / test fabric baby food / cotton 87 93 86 86 grass and mud / cotton 78 77 78 78 tomato puree / cotton 81 82 80 80 red wine / cotton 92 87 91 86 garden dirt / polyester 94 94 94 92 beef tallow / polyester 96 92 93 91 chocolate ice cream / polyester 98 96 99 98 black tea / polyester 96 92 98 98 The results show that Examples 1 and 2 provide parity performance ^SRI: + / - 2.5) against most standard stains when compared to Examples A and B, and improved performance ^SRI > + / - 2.5) for certain polyphenol stains, such as red wine, chocolate ice cream and black tea (especially when compared to Example B). Examples 3 to 5 below illustrate laundry detergent compositions according to the invention. Ingredients % by weight (active ingredients) Formulation Example 3 Example 4 Example 5 LAS acid 10 6 10 alcohol ethoxylate 5 3 5 zeolite builder 20 sodium carbonate 20 enzyme 1 1 2 bleaching agent 0.1 0.1 0.1 sodium percarbonate 15 TAED 1 itaconate surfactant with formula (I) 1.5 9 10 HEDP 1 0.5 0.5 sodium chloride 2 2 sodium hydroxide 1 1 dispersant 1 2 water, small amount sufficient to make 100

Claims

1. An itaconate surfactant having the following formula (I) wherein R1 is selected from an aliphatic hydrocarbyl group having 4 to 22 carbon atoms; R is selected from hydrogen and an aliphatic hydrocarbyl group having 1 to 4 carbon atoms; and n is an integer ranging from 8 to 20.

2. A surfactant according to claim 1, wherein R1 in formula (I) is selected from a linear alkyl or linear alkenyl group containing from 12 to 18 carbon atoms and 0 or 1 double bond. o 3. A surfactant according to claim 1 or claim 2, wherein R in formula (I) is methyl.

4. A surfactant according to claims 1 to 3, wherein n in formula (I) ranges from 8 to 10.

5. A process for preparing an itaconate surfactant of formula (I) according to claim 1, said process comprising the steps of: (i) reacting an itaconic anhydride with an alcohol of general formula R1OH (wherein R1 is as defined in claim 1) to produce an itaconate ester; and (ii) oxylating the itaconate ester to produce an itaconate surfactant of formula (I).

6. A process according to claim 6, comprising the steps of: (i) reacting itaconic anhydride with an alcohol of general formula R1OH (wherein R1 is as defined in claim 1) to produce an itaconate ester; (iia) reacting polyethylene glycol of formula R2O(CH2CH2O)n-CH2CH2OH (wherein R2 and n are as defined in claim 1) with a sulfonyl halide, to form an intermediate; and (iib) reacting the itaconate ester obtained in (i) with the intermediate obtained in (iia) to produce an itaconate surfactant of formula (I).

7. A laundry detergent composition comprising from 0.5 to 35% (by weight based on the total weight of the composition) of an itaconate surfactant according to any one of claims 1 to 4.

8. Use of the composition according to claim 7 for cleaning polyphenol stains.