GB2189787A - Alkyl polyoxyalkylene carboxylate esters - Google Patents

Description

SPECIFICATION Alkyl polyoxyalkylene carboxylate esters This invention relates to surface active agents useful as emollients in skin care compositions.

The invention provides compounds offormula I, and mixtures thereof,

in which R is C8-C22 alkyl; R1 isC1-C22alkyl; m is 0 or an integer 1 to 4; n is an integer 3 to 20; oisanintegeri to4;and p isO or an integer 1 to 20, with the provisos that: 1) when R1 is C1-C3 alkyl,then p is 0; and 2) when mis 0, n is an integer 6 to 20.

R is preferably C10-C18 alkyl, more preferably CrO-Cr6 alkyl.

R1, when p is other than 0, is preferably C6-C8alkyl, more preferably C10-C16alkyl.

R1, when p isO, is preferably C3-C18 alkyl, particularly isopropyl orcetyl.

The variable m is preferably 0 or 2.

The variable n, when m isO, is preferably 6 to 18, more preferably 6 to 14.

The variable n,when m is other than 0, is preferably 3 to 12, more preferably 3 to 10.

The variable o is preferably 1 to 3, more preferably 1 or 2, particularly 1.

The variable p is preferably 0 or an integer 1 to 16, more preferably 0 or an integer 1 to 12, most preferably 0.

The variables m,n, o and pare averagevalues. As is clearly evident, the variables mn, o and p must be whole numbers in the individual compounds ofthis invention.

All alkyl groups may be straight or branched chain unless otherwise stated.

Preferred compounds and mixtures arethose offormula la:

in which R' is C10-C18 alkyl; R1 when p' isO, is C3-C18 alkyl or, when p' is otherthan 0, is CsC18 alkyl; m is as defined above; n',when mis 0, is an integer6to 18 or, when mis otherthan 0, is an integer3 to 12; o' is an integer 1 to 3; and ptisOoraninteger1to16.

The more preferred compounds and mixtures are those offormula lb:

in which R" isC10-C16alkyl; R1"when p" isO, is C3-C18 alkyl and, when p" is otherthan 0, is C10-C16alkyl; m is as defined above; n",when mis 0, is an integer 6 to 14 or, when mis otherthan 0, is an integer3to 10; o"isaninteger1 or2; and p"is0oranintegerltol2.

The most preferred compounds and mixtures are those offormula Ic

in which R", nD and R1" are as defined above and m'isOor2, particularly those in which R1,, is isopropyl or cetyl.

Suitable alcohol precursors of the alkyl polyoxyalkylene carboxylate esters ofthis invention are straight or branched chain primary alcohols having from 8 to 22 carbon atoms. A mixture of alcohols may be used and this will generally be the case when using commercial alcohols which are often available as a blend of several alcohols. Specific examples are a mixture of C12-Cls straight chain alcohols available commercially from Union Carbide; a mixture of C12-C15 predominantly straight chain alcohols containing approximately 20% branching available commercially from Shell Chemical Co.; and a mixture of alcohols, at least 70 mol %of which is branched 1 -decanols available commercially from Exxon Chemical Co.When employing a mixture of alcohols,the numberofcarbon atoms in the alcohols is referred to as average numberwhich can be determined by vapor phase chromatography and the hydroxyl number.

The compounds and mixtures offormula I are produced by conventional methods. Thus, the alkyl polyoxyalkylene carboxylate esters ofthis invention may be prepared by carboxyalkylating the adduct resulting from the propoxylation and/or ethoxylation of a straight of branched chain primary alcohol having from 8to 22 carbon atoms and then esterifying the resulting carboxyalkyiated acid with a straight or branched chain primary alcohol optionally containing one or more ethylene oxide groups.

The alkoxylation step may be carried out in the presence of an alkaline catalyst, e.g. sodium or potassium hydroxide, in an amount e.g. fro 0.2% to 1% by weight ofthe total reaction mixture.

Optionally, a small amount of a reducing agent may be added to the alcohol, or mixture thereof, to be alkoxylated to minimize discloloration ofthe resulting polyalkoxylated alcohol. Suitable reducing agents which may be employed include sodium borhydride, lithium aluminum hydride and diborane, preferably sodium borohydride.

In preparing a polyoxyalkylated alcohol in which the polyoxyalkylene chain contains a propylene oxide first block and an ethylene oxide second block, an amount of propylene oxide calculated to provide the desired degree of propoxylation is intriduced and the resulting mixture is allowed to react until the propylene oxide is consumed, as indicated by a drop in reaction pressure. A similar introduction and reaction of a calculated amount of ethylene oxide serves to provide the second block which completes the alkoxylation.

Customarily,the alkoxylated product is finally treated with weak acid, e.g., glacial acetic acid, to neutralize any basic catalyst residues.

Is should be understood that each separate alkoxylation procedure serves to introduce a desired average number of alkylene oxide units per alcohol molecule. Thus, for example, the initial treatment of an alcohol mixture with m moles of propylene oxide per mole of alcohols serves to effect the propoxylation of each alcohol moiety with propylene oxide to an average of m propylene oxide moieties per alcohol moiety, although some alcohol moieties will have become combined with more than m propylene oxide moieties and somewill have beccime combined with iess than m. In general, the maximum number of propyleneoxy units in a single moleculewill not exceed 8 and the number of ethyleneoxy units in a single moleculewill not exceed 30.The variation in the number of alkylene oxide moieties is not critical as long as the average forthe number of units in each block is within the limits set out for the m and n terms in formula I above, which terms, as average values, are other than whole numbers in some instances.

Alkoxylation is carried out under conventional conditions of temperature e.g. 140-1 60 C; at a pressure below atmospheric; and in the absence of water.

The resulting alkyl polyalkoxide intermediates are then carboxyalkylated bytheWilliamson synthesis, involving reaction with the appropriate chloro- or bromocarboxylic acid or a salt thereof in the presence of sodium hydroxide or metallic sodium. Such reaction is ordinarily not complete; hence the reaction product often contains minor amounts of uncarboxylated alkyl polyalkoxide. While methods are availablefor separating the uncarboxyalkylated material as well as for assuring essentially complete carboxyalkylation, they are usually tedious and expensive. Fortunately, it has been found that minor proportions of such uncarboxylated material are not particularly harmful, and may even be advantageous. Preferably, the carboxyalkyl group is a carboxymethyl group, i.e. the variable o is preferably 1.

The alkyl polyalkoxide carboxylic acid is then esterified by reaction with a straight or branched chain C1-C22 primary alcohol optionally containing one or more ethylene oxide groups at a mole ratio of alcohol or carboxylic acid offrom greater than 5:1 to 1:1, and in the presence of a catalyst. Typical catalysts include sulphuric acid, hydrogen chloride,p-toluenesulphonic acid and boron trifluoride. To drivethe reaction to completion, water may be removed as it is formed for example by azeotropic distillation. Alternatively, a large excess of one of the reactants (usually the alcohol) may be used. For example, an alkyl polyalkoxide carboxylic acid dried under vacuum can be dissolved in a molar excess of an anhydrous alcohol which forms a low boiling azeotrope with water.An acidic catalyst is then added to the mixture, and the reaction is allowed to proceed at reflux until the reaction is essentially complete (usually between 2 and 48 hours). The excess alcohol and water and then removed by distillation at atmospheric pressure and ester is obtained by decantation. Alternatively, an anhydrous alkyl polyalkoxide carboxylic acid is mised with an equimolar portion of a high boiling alcohol. An acidic catalyst isthen added and the resultant mixture is heated under vacuum, the water of reaction being removed at a temperature between 1 2or and 200 C. After the theoretical amount of water is collected, the mixture is cooled, the vacuum is broken with nitrogen and the ester is obtained by decantation.

The compounds offormula I are useful as surface active agents, and are suitable as emulsifiers, dispersing agents, lubricants, wetting agents, levelling agents, softening agents and the like in the textile, leather, paper, lacquer, personal care, e.g., toiletries, cosmetics, etc., and rubber industries. For instance, they can be used as wetting, softening or lubricating agents in the treating and refining of textiles; and for converting liquid or solid substances which are insoluble in water (such as hydrocarbons, higher alcohols, oils, fats, waxes and resins) into creamy emulsiins, clear solutions or fine, stable dispersions.

In addition, the compounds offormula I are useful as emulsifiersfor insecticide compositions and agricultural sprays such as DDT, 2,4-D and the like; are useful as additives to petroleum products, hydraulic fluids, lubricating oils, cutting oils and greases; may be employed as coating aids for use in coating compositions comprising a hydrophilic,film-forming colloid; may be employed astackifiers in theadhesive layer of adhesive tapes in, e.g., the photographic industry; and asfoaming agents, emulsifying agents and softening agents in a wide variety of food products.

The alkyl polyoxyalkylene carboxylate esters of the instant invention are especially useful as the essential emollient component in skin care compositions, e.g., skin creams, lotions, etc. Their incorporation serves to enhance not only the moisturizing and conditioning properties ofthe skin care compositions butthetactile properties as well. Such skin care compositions will normally contain from 0.5%to 15% bywt. of alkyl polyoxyalkylene carboxylate ester, preferably from 1% to 13%, and more preferably from 1.5% to 12%. The alkyl polyalkoxylene carboxylate esters are preferably employed as the sole emollient component, totally replacing conventional fatty ester emollients such as isopropyl myristate, isopropyl palmitate and similar compounds.Alternatively, the carboxylate esters may be employed in combination with conventional fatty ester emollients, thereby reducing the amount of conventional fatty ester emollient that needs to be employed.

The skin care compositions can contain other ingredients commonly found in such compositions. For example, fatty alcohols may be employed to assist in stabilizing the composition and in providing a cosmetically acceptable viscosity. In general, a C14to C22 substantially saturated aikanol is employed. Typical examples of suitable fatty alcohols are cetyl alcohol and stearyl alcohol.

Emulsifiers may also be employed and such may be cationic e.g., quaternary ammonium compounds such as dimethyl distearyl ammonium chloride, amphotericsuch as betaines orsulfobetaines and nonionic such as polyethylene glycol monostearate.

In order to improve the lubricity of the skin care compositions, a lubricant is generally employed. This may be a silicone oil such as dimethylpolysiloxane or other conventional polysiloxane or olive oil.

If desired, a humectant may be present in the skin care composition. Typical humectants which may be employed inciude propylene glycol and polyethylene glycol.

The amount of water or aqueous vehicles to be included depends upon the desired consistency ofthefinal product. It is possibletovarythe amountofwater presenttoformulate,forexample, a thick4lowing liquid or lotion, a semi-liquid thick cream or a paste.

The skin care compositions, in general, comprise from 1.5% to 10%, preferably from 2% to 8.5% of a fatty alcohol; from 1.5% to 12%, preferably from 2% to 10% of an emulsifying agent; and from 0.75% to 50%, preferablyfrom I%to 25% of a lubricant all percentages being byweight Other conventional additives typically employed in skin care compositions may be utilized. Fragrance oils, which maskthe odor and provide cosmetic appeal, can be employed. Non-toxic and compatible dyes may be utilized to colour the compositions, as desired. Preservatives, such as methyl paraben, propyl paraben and formaldehyde may be utilized.

In addition, other ingredients can be employed beneficially to provide skin-care compositions tailored to a specific use. For example, a sun screen additive such as octyl dimethyl para-aminobenzoic acid can be employed. To provide skin protection, a skin protectant such as zinc oxide and the like can be employed. As a medicament, an essential oil such as methol can be employed.

The skin care compositions ofthe invention exhibit good consistency, apply evenly to the skin, are absorbed rapidly and dry quickly, leaving the skin with a soft and smooth appearance. On application they have good tactile properties without feeling oily or greasy to the touch.

The following examples in which all parts are by weight and all temperatures in degrees centigrade illustrate the invention.

Example 1: Isodecyl-dipropoxy-hexaethoxymethyl carboxylic acid, isopropyl ester iso-C,OH210(C3H60)2(C2H40)6CH2COOCH(CH3)2 A) Preparation of dipropoxy-hexaethoxy isodecyl alcohol To a reaction vessel is added, with stirring, 705 parts of decyl alcohol ( a mixture of primary, aliphatic alcohols, at least 70 mol % of which is branched 1 -decanols, a boiling range of 216"two 223 , a specific gravity &commat; 20/20 of 0.838, a refractive index, nod20, of 1.400, a pour point of -53", a viscosity &commat; 20 of 22.5 centistokes and a solubility in water&commat;;20 of < 0.05 g/l 00 g and available commercially from Exxon Chemical Co.),10.6 parts of potassium hydroxide (in pelletform) and 0.12 parts of sodium borohydride. The system is evacuated and purged with nitrogen three times at 60", then heated to 100 .260 Parts propylene oxide are then added over 60 min. the reaction temperature rising to 155 . After allowing the reaction mixture to react further until the pressure in the reaction system falls to approx. 10 mbar,the procedure described above is repeated with an additional 257 parts of propylene oxide, added over a period of sixty minutes. After allowing the procedure described above is repeated with 1178 parts of ethylene oxide, added over a period of sixty minutes.When reaction is complete, the reaction system is purged with nitrogen, cooled to 85 and an additional 0.12 parts of sodium borohydride is added. The reaction system is then kept under a nitrogen atmosphere for 2 hours, at 80'-90', the catalyst present is neutralised with glacial acetic acid and the product filtered to yield a translucent, pale yellow liquid oftheformula iSO--CIOH21 (OC3H6)2(OC2H4)6OH B) Preparations of isodecyl-dipropoxy-hexaethoxy-methyl ca rboxylic acid To 957.6 parts of the compound prepared in A) above, is alternately added, in samll portions over a period of 3 1/2 hours at a temperature range of 25"-50", equimolar amounts of sodium hydroxide (71.2 parts) and sodium monochloroacetate (207.7 parts). Upon completion of the addition, the temperature of the resulting reacting mixture is maintained at 50' for 30 minutes, after which time the temperature is raised to 75 over a period of 30 minutes.After keeping the reaction mixture at a temperature of 75' for 90 minutes, it is cooled to 500 and acidified with 175 parts of sulphuric acid (50% conc.) and 600 parts of water, after which time separation of the water soluble salt yields an oil oftheformula CloH210(C3H60)2(C2H40)6CH2COOH C) Preparation of the title compound 158.7 Parts of the compound prepared in B) above are heated to 60 under vacuum in a reaction vessel.

After 12.7 parts of water are collected,the reaction vessel is cooled and the vacuum broken. 100 Parts of anhydrous isopropanol (mole ratio alcohol; acid approx. 8:1) and then added to the reaction vessel, after which time a catalytic amount (25 drops) of 98% sulphuric acid is added to the reaction mixture. The resultant mixture is then heated to refluxtemperature and maintained at this temperature for a period of 24 hours.

After removal of isopropanol and water by distillation, decantation yields the title compound.

Example 2: Isodecyl-dípropoxy-hexaethoxymethyl carboxylic acid, cetyl ester iso-C10H21O(C3H6O)2(C2H4O)6CH2COOC1eH33 158.7 Parts ofthe compound prepared in Example 1 B) above are heated to 50 undervacuum in a reaction vessel. After 14 parts of water are collected, the reaction vessel is cooled and the vacuum broken.An equimolar amount (48.2 parts) of cetyl alcohol is then added to the reaction vessel and the mixture heated until the alcohol completely melts. A catalytic amount (5 5 drops) of 98% sulphuric acid is then added and the resultant mixture heated to 130 undervacuum. After3 hours, 3.9 parts of water are collected.The mixture is cooled to Sand the title compound recovered by decantation.

Example 3: Lauryl-hexaethoxymethylcarboxyllc acid, cetylester C,2H250(C2H40)6CH2COOC1 6H33 A) Preparation of hexaethoxy lauryl alcohol To a reaction vessel is added, with stirring, 664.7 parts of lauryl alcohol and 8.5 parts of potassium hydroxide (in pellet form). The system is purged with nitrogen at 100" then heated to 160', at which pointthe addition of 1059 parts of ethylene oxide to the reaction misture is commenced. The temperature ofthe resulting reaction mixture is kept at 160"-170"throughoutthe gradual addition of ethylene oxide.Upon completion of the ethylene oxide addition, the reaction mixture is cooled to yield a compound oftheformula C12H25(OC2H4)60H B) Preparation of lauryl-hexaethoxy-methyl carboxylicacid Following essentiallythe procedure of Example 1 B), and using in place of the compound prepared in Example 1 A), an approximately equivalent amount of the compound prepared in A) above, a compound of the formula C,2H250(C2H40)6CH2COOH is obtained.

C) Preparation of the title compound Following essentiallythe procedure of Example 2, using 101.6 partsofthe compound prepared in B) above in place of the 158.7 parts of the compound of Example 1 B), the title compound is obtained.

Example 4: Lauryl-hexaethoxymethyl carboxylic acid, isopropyl ester C12H250(C2H40)6CH2COOCH(CH3)2 Following essentiallythe procedure of Example 1 C), and using in place of the compound of Example 1 B) an approximately equivalent amount of the compound of Example 3 B), the title compound is obtained.

Example 5: A) Following essentiallythe procedure of Exampie 3A) and employing the appropriate starting alcohol and the appropriate amount of ethylene oxide, the following compounds are obtained: a) Ra(OC2H4)8OH where Ra is the residue of a mixture of C12-C15 predominantly straight chain alcohols containing approximately 20% branching and availablecommerciallyfrom Sheli Chemical Co.; b) Rb(OC2H4)12OH where Rb is the residue of a mixture ofC12-C15 straight chain alcohols and available commercially from Union Carbide;; c) RC(OC2H4)110H wherein RC is the residue ofa mixture of primary, aliphaticalcohols, at least 70 mol %ofwhich is branched 1-decanols and available commercially from Exxon Chemical Co.; d) Rd(OC2H4)10OH where Rd is the residue ofa commercially available isostearyl alcohol containing a mixture of branched methyl isomers; and e) C16H33(OC2H4)10OH.

B) Following essentially the procedure of Example 3 B), and using a place of the compound prepared in Example 3 A), an approximately equivalent amount of compounds 5 A) a) - e),there is obtained: a) RaO(C2H4O)8CH2COOH b) RbO(C2H4O),2CH2COOH c) RCO(C2H40)11CH2COOH d) RdO(C2H4O)OCH2COOH, and e) Cr6H33O(C2H4O),OCH2COOH, respectively.

C) a) Following essentiallythe procedure of Example 2 and using in place of the compound prepared in Example 1 B), an approximately equivalent amount of compounds 5 B) a) - e), there is obtained: a) RaO(C2H4O)8CH2COOC16H33 b) RbO(C2H4O)12CH2COOC16H33 c) R"O(C2H40)11CH2COOC16H33 d) RdO(C2H4O)10CH2COOC16H33, and e) Ca6H33O(C2H4O)oCH2COOCr6H33, respectively.

Examples 6- 10: Following essentially the procedure of Example 1 C), and using in place of the compound prepared in Example 1 B), an approximately equivalent amount of the compounds of Examples 5 B) a) -e),thereare obtained the isopropyl esters corresponding to the compounds 5 C) a) - e).

It should be understood that in all of the Examples above, the indicated number of propyleneoxy units and ethyleneoxy units are average values.

Example ii: A body cream formulation contains the following ingredients: Ingredients Weight Percent cetyl alcohol 2.5 stearyl alcohol 5.0 lightsilicone oil 1.0 Pationic SSLR (amphoteric emulsifier) 1.5 water 82.6 propylene glycol 5.0 compound of Example 1 2.0 The above formulation is prepared by heating thewaterto 70 , heating the remaining ingredients to 70', and after adding the water slowly, with stirring, to the heated mixture of ingredients, allowing the resultant mixture to cool to room temperature.

Examples 12- 14: In the formulation of Example 11, the compound of Example 1 may be replaced by the compounds of Examples 7,8 and 9.

Example 15: An oil-in-water body lotion formulation containsthefollowing ingredients: Ingredients Weight Percent A. polyethylene glycol (400) monostearate 2.5 olive oil 47.5 propyl paraben 0.15 Compound of Example 2 2.5 B. methyl paraben 0.15 water 46.8 The aboveformulation is prepared by combining and heating the components of Ato 70 , combining and heating the components of Boo 700, and after adding Ato B, with stirring, allowing the resultant mixture to cool to room temperature.

Examples 16- 18: In the formulations of Example 15, the compound of Example 2 may be replaced by the compounds of Examples 5 C) b), c) and d).

Example 19: An oil-in-water body lotion formulation contains the following ing redients: Ingredients Weight Percent A. Arlacel 60 (non-ionic emulsifier) 2 Tween 60 (polysorbate) 3 Compound of Example 1 10 B. water 85.

The above formulation is prepared by combining and heating the components of 70', heating the water to 72", and after adding the water slowly, with stirring, to the heated mixture of ingredients, allowing the resultant mixture to cool to room temperature.

Examples 20 - 21: In the formulation of Examples 19, the compound of Example 2 may be replaced bythe compounds of Examples 7 and 8.

Claims (13)

1. Compoundsofformula I

in which R is C8PC22alkyl; R1 isC1-C22alkyl; m is 0 or an integer 1 to 4; n is an integer 3 to 20; oisanintegerl to4;and p isO or an integer 1 to 20, with the provisos that: 1) when R1 is C1-C3alkyl,then p isO; and 2) when m is 0, n is an integer 6 to 20 and mixturesthereof.

2. Compounds as claimed in Claim 1 offormula la

in which R' is C10-C18 alkyl; R1, when p' isO, is C3-C18 alkyl or, when p' is otherthan 0, is C6-Cr8alkyl; mis as defined in Claim 1, n',when mis 0, is an integer 6 to 18 or, when mis otherthan 0, is an integer 3 to 12; o' is an integer 1 to 3; and p' isO or an integer 1 to 16, and mixturesthereof.

3. Compounds as claimed in Claim 2 offormula Ib

in which R" isC10-C16alkyl; R1" when p" is 0, is C3-C18 alkyl and, when p" is otherthan 0, is C10-C16alkyl; m is as defined above; n",when mis 0, is an integer6to 14 or, when mis otherthan 0, is an integer3to 10; o" is an integer 1 or 2; and p" is O or an integer 1 to 12, and mixturesthereof.

4. Compounds as claimed in Claim 3 of formula Ic

in which R", n" and Ra N are as defined in Claim 3 and m' isO or2, and mixturesthereof.

5. Compounds as claimed in Claim 4 in which R1" is isopropyl orcetyl, and mixtures thereof.

6. Acompoundofformula iso-C10H21O(C3H6O)2(C2H4O)6CH2COOCH(CH3)2.

7. Acompoundofformula RaO(C2H4O)8CH2COOC16H33 in which Ra is the residue of a mixture of C12-15 predominantly straight chain alcoholscontaining approximately 20 % branching.

8. Acompoundofformula R O(C2H4O)8CH2COOCH(CH3)2 in which Ra is as defined in Claim 7.

9. A compound as claimed in Claim 1 as described in anyone of Examples 2,3 c),4, SC b)- e) and 7-10.

10. A skin care composition comprising from 0.5% to 15% by weight of a compound as claimed in any one of Claims 1 - 9, or mixtures thereof.

11. A skin care composition as claimed in Claim 10 which a compound or mixture of compounds as claimed in Claim 1 is the sole emollient component.

12. A skin care composition as claimed in Claim 10 or Claim 11 containing in addition from 1.5 % to 10 % of a fatty alcohol, from 1.5 %to 12 % of an emulsifying agentandfrom 0.75 %to 50 % of a lubricant,all percentages being weight.

13. A skin care composition as described in any one of Examples 11-21.