US 3345300 A
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DETERGENT coiwPosrTroN CONTAIN- ING. MIXED ANIONIC CATIONIC SURFACTANTS Henry C. Speel, Evanston, Ill., assignor to Universal Oil 7 Products Company, Des Plaines, 111., a corporation of Delaware No Drawing. Filed Dec. 10, 1952, Ser. No. 258,937 11 Claims. (Cl. 252-152) comprising a mixture of an anionic detergent of specific structure and a cationic surfactant (surface active agent) generally, the composition having unique surface active properties in aqueous solution. More specifically this invention relates to a mutually compatible mixture of a cationic surfactant and an anionic detergent comprising an alkali metal salt of a polybasic acid ester of a polyol condensate containing a hydrophobic hydrocarbon radical linked to the polyol through an oxy or carboxy radical, each of the anionic and cationic surfactant components contributing its specific advantageous properties to the composition.
It is Well-known in the art of surfactants that cationic surfactants in general are incompatible with anionic detergents in the same solution, both the cationic and anionic ingredients losing their surface active properties by virtue of interaction between the negatively-charged hydrophobic. group of the anionic detergent and the positively-charged, hydrophobic group of the cationic surfactant, e.g.,
Thus, by virtue of such interaction betwen the cationic and anionic groups the surface active properties of both ingredients are cancelled out because the radicals which are responsible for the surface activity of each component are rendered ineffectual through such neutralization and the resultant precipitation or separation of the molecular complex from solution.
However, it has now been discovered that a certain class of anionic detergents of the type hereinafter characterized may be mixed or composited with any member of the broad class of cationic surfactants generally to form a surfactant composition having detergent and surface activity greater than the separate components individually and the resulting mixture has a unique combination of properties which provide a laundering composition having especially advantageous properties for laundering cotton fabrics, synthetic fibers and wool in aqueous solution. These products not only have the high degree of surface activity which characterizes the anionic long chain fatty acids soaps, but their detergency for cotton fabrics in hard water is maintained, and in many instances the over-all washing value of the product is improved when composited with a cationic surfactant.
In the past several decades the large consumption of fatty acid soaps heretofore observed has given way increasingly to the use of anionic, ,nonionic, and amphoteric detergents having radicals other than carboxylate which enable the detergent action to be insensitive to bivalent metal ions, such as the alkaline earth metal ions present in hard water. The contrast in sensitivity to hard wateris marked by the tendency of the fatty acid soaps to form the so-called lime soap precipitate or scum in hard water '10 This invention relates to a novel composition of matter ice and the absence of such precipitate in the use of synthetic detergents which contain a strongly anionic radical such as sulfate or sulfonate.
With the rapidly expanding consumption of anionic detergents, however, other problems of more devious character have arisen, including the increasing contamination of the sources of potable water, arising out of the'nonbiodegradability of many synthetic detergent products. These materials find their way into ground water sources from streams into which the efiluents of sewage treatment plants have been dumped. The sewage effluent in spite of its low B.O.D. character and apparent clarity, nevertheless contains in solution the non-degraded synthetic detergent which was introduced initially into the sewage .by the consumer of the detergent. During the many years of using fatty acid soaps no problem of underground carryover of detergents into the public Water supply has existed because it has been easy to convert soluble soaps to insoluble soaps by chemical treatment in the sewage plant. Moreover, the relative ease of bacterial digestion of the long, straight chain hydrocarbon group of the fatty acid simplifies removal where activated sludge disposal methods are employed. In the case of the anionic, synthetic detergents containing a sulfonate radical, however (a major proportion of which contain a long chain,'alkyl-substituted aryl hydrocarbon group), the long chain alkyl group is frequently of branched chain structure and relatively resistant to bacterial digestion. The
result of such insensitivity to precipitation in the presence of alkaline earth metal ions and the non-biodegradability of the detergent molecule is that most sewage treatment plant effluents contain sufiicient detergent residue to cause foaming in natural streams carrying away such efi luents and subsequent contamination of well water supplies by percolation of these efi luents into the substrata water sources; I
The present detergent compositions contain an anionic detergent component having the hydrocarbon structure of a fatty acid salt radical (a relatively straight chain, biodegradable structure) and also having the desirable laun dering properties possessed by a fatty acid soap type of detergentThe present anionic detergent ingredient, however, diifers from a fatty acid soap in the fact that the carboxylate salt group is one of the neutralized acid sites of a polybasic acid and the one or two remaining acid sites of the polybasic acid is esterfied by the hydroxyl groups of a poly-oxyalkylene alcohol condensate. In other words, the hydrophilic character of the anionicdetergent component is not dependent solely on the carboxylate salt group, but is also partially dependent on the hydrophilic poly-oxyalkylene chain. When the alkali metal of the carboxylate group is replaced by an alkaline earth metal (normally a curd-forming reaction), a precipitate does'not form because the poly-oxyalkylene chain adds suir'icient hydrophilic character tothe surfactant to maintain the molecule asa whole in aqueous solution, irrespective of replacement of the alkali metal from the carboxylate salt of the polybasic acid With an alkaline earth metal. Since the ester linkage between the polybasic acid group and the poly-oxyalkylene condensate is subject to rupture by chemical means and by bacterial action, the
water-solubilizing properties contributed by the polybasic acid portion of the molecule can be readily eliminated by breaking the ester linkage. Furthermore, by choosing (for the hydrophobic portion of the molecule a straight chain structure readily degraded by bacterial action, or by employing ,an ester linkage between the hydrophobic and the polyoxyalkylene chain, or by suitably adjusting the length of the polyoxyalkylene chain, a water-insoluble portion is left after the polybasic acid structure is lost. Thus, the tendency of the hydrophobic hydrocarbon radical to carry-over into the sewage disposal effiuent and eventually to contaminate a natural water supply, does not obtain and is not concomitant with the use of the anionic component of the present detergent composition. It is also feasible to utilize the more readily available, relatively non-straight chain alkyl hydrocarbon groups having, for example, a poly-methyl-substituted alkyl chain as the source of the hydrophobic, hydrocarbon portion of the anionic molecule (or various cyclic or acylic hydrocarbons such as a tall oil mixture, an alkyl phenyl group in which the alkyl group is derived from a poly-olefin, such as polypropylene), a fatty acid radical or a long chain oxo-alcohol radical which when cleaved from the ionic portion of the molecule is no longer soluble in Water and therefore is no longer surface active. After splitting off from the hydrophilic portion of the present anionic detergent molecule in the sewage digestion or acid treatment of the sawage stream in which the detergent is present, the hydrophobic radical having been derived from a straight chain alcohol or straight chain fatty acid, provides a biodegradable hydrophobic residue which renders the present anionic detergent ingredient totally destructible during the subsequent treatment of sewage containing the detergent in a sewage treatment plant. Even if derived from a non-biodegradable hydrophobic hydrocarbon group, such as a branched chain alkyl-substituted aromatic hydrocarbon, upon rupture of the ester linkage during sewage digestion or acid treatment, the hydrophobic hydrocarbon portion of the molecule is insoluble and floats to the surface of the water.
The specific anionic detergent ingredient of the present invention also possesses the unique property of contrib-ut. ing to the dispersability and penetrability of dyes into the fibers of textile fabrics. Dyes normally insoluble in water are completely dispersed in aqueous solutions in which the present anionic ingredient is present in detergent concentrations as low as 0.3 percent, a concentration level generally considered effective for most cleaning and laundering operations.
The cationic ingredient of the present detergent composition which unexpectedly does not precipitate in admixture with the anionic detergent component of the present composition imparts a desirable soft finish to fabrics, particularly to cellulose fabrices, laundered in an aqueous solution containing the present cationic detergent component in admixture with the anionic component. This property, referred to in the laundering art and in the textile industry, and a hoped-for property of the detergent formulator, is referred to as having the capacity to impart a desirable feel or hand to the fabric, in that the fabric ripples readily on being brushed and possesses a distinctive smooth snedy handle, a velvety texture to the touch. Such property is unique to certain cationic detergents and no-truly comparable instance of its presence in anionic detergents is known. As hereinbefore indicated, however, most anionic detergents cannot be used in combination with cationics because of the tendency of the combination to precipitate out of a solution containing an anionic component and since the cationic component alone provides the desirable feel property to the detergent composition, compatibility of the two types of surfactants and the ability to form a detergent composition having the desired properties is dependent upon the ability of the present anionic detergent ingredient to adapt to the requirements of the mixture. The anionic component of this invention meets these requirements and possesses the es-' sential biodegradability desired in anionic detergents, es-
sential, that is, to the eventual removal from its aqueous solution by bacterial digestion or .acid hydroylsis. In the present detergent composition the unique contributing factors of both the anionic and cationic components are.
acquired by mixing these mutually compatible ingredients in the same detergent composition.
In addition to the foregoing advantages of the present detergent composition, the properties of the anionic component of the mixture may be substantially varied to provide a wide variety of physical and chemical properties in the resulting product. Thus, a product having excellent detergency but low foaming tendency may be produced by means of and through the choice of specific reactants employed in synthesizing the present product. In addition to products having detergent or dispersing values, the product may be tailored to provide good Wetting properties, through the choice of reactants. The penetrating properties of the compound, its capacity to emulsify hydrophobic materials, its .ability to disperse and/or solubilize other media in water and its biodegradability (as described above) may be varied at will to provide products for specific uses through the choice of reactants utilized in the manufacture of the present anionic ingredient.
The provision for .a detergent composition having the foregoing properties, which may be varied at will depending upon the specific application of the composition, constitutes the primary objective of this invention.
In one of its embodiments this invention relates to a detergent composition comprising a mixture of a cationic surface active agent and an anionic detergent, the latter consisting of a mono-alkali metal salt of a polybasic, icarboxylic, mono-ester of the terminal alkylol group of a poly-oxyalkylated organic compound containing a hydrophobic hydrocarbon radical on the opposite end of the poly-oxyalkylene chain which contains from about 2 to about 20 oxyalkylene units having from 2 to 3 carbon atoms per unit, said hydrophobic hydrocarbon radical being further characterized in that it contains from 8 to about 21 carbon atoms.
A more specific embodiment of this invention relates to a detergent composition containing a cationic surface active agent and an anionic detergent of the type having the structure:
wherein R is a monovalent hydrocarbon radical containing from 8 to about 21 carbon atoms, X is selected from the group consisting of oxo, thio, irnino, carboxy and carboxamido, n is a whole number selected from 2 and 3, m is a whole number selected from 2 to about 20, M is an electropositive radical selected from the group consisting of ammonium and an alkali metal, and y and a are whole numbers selected from 1 and 2, said composition containing from about 5 to about percent of the combined anionic and cationic surface active ingredients of said anionic component.
The cationic surfactant ingredient of the present surface active composition is a material in which the electropositive ion formed upon ionization of the surfactant (e.g., by dissolution in an aqueous solvent) is a fat-solubilizing (or hydrophobic) radical. Cationic detergents, generally, are derivatives of hydrocarbon-substituted nitrogen compounds combined with an electronegative radical (generally a halide or sulfate ion) to form an ionizable combination such as:
Hi -PX- is not only sufiiciently hydrophilic to solubilize the molecule as a whole in water but is also sufficiently hydrophilic to. balance the hydrophobic effect of the hydrocarbon r.adi-
'cals (one or more of the R- groups) substituted on the ammonium nitrogen atom. Such balance between the hydrophilic and hydrophobic groups constitutes one of the principal structural requirements for surface activity in aqueous solution.
Typical specific compounds utilizable herein as the cationic surfactant component of the present laundering composition include, generally, the group of compounds characterized as the quaternary ammonium salts containing a hydrophobic hydrocarbon group, such as the alkyltrimethyl ammonium halides in which the alkyl group is a long chain monovalent hydrocarbon radical, (preferably containing from about 8 to about 12 carbon atoms), or a long chain alkyl-substituted aryl hydrocarbon group, such as dodecylphenyl, or an aryl-substituted alkyl radical such as 3-phenyldodecane. Specific compounds included within the scope of the general class of cationic surfactants comprising one of the ingredients of the present detergent composition include the following:
Alkyldimethylbenzylammonium halide in which R is an alkyl group containing from 1 to 12 carbon atoms Cetyldimethylethylammonium halide Hexadecyldi-methylamine hydroacetate Diisobutyl phenoxyethoxy ethyldimethylbenzylam- Lauryl pyridinium halide C5H5EN-C12H25'X Stearamide of diethylene triamine Fatty acid alkyl-derived imidazoline H2 (J-CH2 Quaternary ammonium salts of amino amides- 6 with the anionic detergentingredient of the mixed detergent composition.
The foregoing cationic surfactants are prepared generally by condensing a tertiary alkyl halide with a long chain hydrocarbon-substituted amine which, in turn, is generally prepared by the hydroalkylation of a nitrated hydrocarbon. Thus, an alkyl aromatic hydrocarbon (which forms the hydrophobic portion of the ultimate quaternary ammonium salt) when mono-nitrated and subsequently reduced yields a nuclearly amino-substituted phenyl-substituted alkane; the resulting alkylarylamine undergoes N-alkylation with, for example, a methyl halide, such as methyl bromide to form a cationic quaternary ammonium halide salt having surface activity in aqueous solution. Other methods of synthesis are also available to form the cationic detergent component and are within the contemplated scope of the methods proposed for the production of the present cationic surface active agents. V
The cationic surfactant ingredient is present in the detergent composition in amounts of fromabout 5 percent to about percent, and more preferably, from about 10 to about 50 percent by weight of the combined anionic and cationic surfactant ingredients of the present laundering composition. In general, the detergent composition will have the capacity to impart the softening quality to cotton fabrics laundered in aqueous solutions of the composition if the latter contains the cationic surfactant component to the extent of at least 5 percent and more preferably, at least 20 percent by weight of the combined Surfactant ingredients.
The anionic detergent component of the composition herein provided, generally the surface active agent present in greatest proportion in the composition, is a compound characterized as an ether-alcohol mono-esterof a polybasic acid (preferably a dibasic acid) prepared by synthetic means, having the structure represented by the fol-. lowing empirical formula:
in which the values of R, X, n, rm, y, M, and a have the values hereinabove specified. The method of synthesizing the specific compounds within the scope of the above formula generally involves at least a two-part procedure. In the initial stage a compound having a hydrophobic hydrocarbon radical in'its structure and an active hydrogen atom attached to sulfur, oxygen, carboxyl or nitrogen, such as an alkylphenol, a long chain aliphatic alcohol, a long chain fatty acid, an alkyl-substituted thiophenol 'or an alkyl-substituted aliphatic or aromatic amine in which the total number of carbon atoms in the hydrocarbon substituents and groups present in the R radical of the above formula is within the range of from about 8 to about 21 carbon atoms, is condensed with an alkylene oxide selected "from ethylene oxide and propylene oxide or with an alkylene halohydrin to form a mono-oxyalkylated intermediate, followed by further condensation of the terminal alkylol group (ethylol: HOCH C1-I or propylol: H CCHOHCH depending upon whether the intermediate reaction is an oxyethylating or an oxypropylating reaction) with an alkylene oxide to form a polyoxyalkylene chain attached to the hydrophobic hydrocarbon-substituted carboxyl group, phenol, alcohol, thiophenol or amine in place of one or both of the condensable, active hydrogen atoms on the carboxyl, hydroxyl or sulfhydryl groups p-resentin the latter compounds. Thus, in the case of alkylphenol which contains a nuclear hydroxyl group having an active hydrogen atom, the alkylene oxides condense with such a phenol in the presence of an alkaline catalyst such as' sodium hydroxide or so dium methylate, to form the first stage intermediate polyoxyalkanol which is subsequently condensed with the polybasic acid or its monocarboxylate salt reactant to form one species of the ultimate anionic detergent com-' ponent of this invention. These continuing condensations are represented by the following equations, using the preferred dibasic acids and the initial alcohol-ether intermediate of the above exemplary Equation 1:
Instead of the di'basic acid or its mono-salt reactant indicated in the above equations for illustrative purposes, the anhydride derivative of the dibasic acid may also be utilized in the foregoing condensation reaction.
For other types of compounds having an active hydrogen atom condensable with the poly-oxyalkylating agent, a similar condensation reaction occurs. Thus, in a starting compound, such as a thiophenol containing a su'lfhydryl group, the condensation of the thiophenol with one mole of an alkylene oxide, such as ethylene oxide, yields the following intermediate:
in which the terminal hydroxyl group is further condensable with alkylene oxide to form a poly-oxyalkylene chain. A long chain fatty acid such as lauric acid, palmitic acid, oleic acid, stearic acid, etc., the intermediate oxyethylated ester is the following:
contains from to carbon atoms. In the case of an alkylaryl amine (which contains two active hydrogen atoms of varying activity) the intermediate formed upon condensation with an alkylene oxide, such as ethylene oxide, generally contains a hydrophilic poly-oxyalkylene chain although at certain reaction conditions, depending upon temperature, the presence of a catalyst, the effect of the laws of chance, etc., two chains may form simultaneously on the amino nitrogen atom, as follows:
(onionzotnn where Z is hydrogen or another (CH CH O) H group. A major proportion of the intermediate oxyalkylation product involving a primary amine as starting material, however, contains a single poly-oxyalkylene chain. Each of the poly-oxyalkylene chains contains a terminal hydroxyl group subject to esterification by the polybasic acid in the second stage of'the present process.
The resulting condensation product which contains from 2 to about 20 oxyalkylene units (the value of m in the above formula) also inherently contains a terminal hydroxyl group at the end of each of the poly-oxyalkylene chains. In the second phase of the process whereby the ultimate anionic detergent product is formed from the intermediate poly-oxyalkylated product containing the one or more poly-oxyalkylene chains having an hydroxyl group at the end of each of the poly-oxyalkylene chains, the condensate is esterified with a polybasic acid containing two or three carboxyl groups per molecule or a dibasic acid monoor dihalide or anhydride in a condensa tion-type reaction to form an ester containing a free canboxyl group at the end of the chain. The latter product is converted to the monoor dialkali metal or the corresponding monoor diammonium carboxylate salt by neutralization of the free carboxyl group(s) introduced by the polybasic acid reactant with an alkali metal, ammonium, or amine base. The resulting carboxylate salt is the anionic detergent component of the present detergent composition.
In general, the common fatty acids, the long chain alcohols of the aliphatic series, such as cetyl alcohol, the alcohols formed by hydrogenating a fatty acid such as stearic acid, oleic acid and linoleic acid derived from a natural fat, and the group of compounds referred to as alkylphenols containing a hydrophobic long chain alkyl substituent on the phenyl nucleus (represented, for example, vby such alkylphenols as: octylphenol, nonylphenol, decylphenol, dodecylphenol, etc.) are preferred not only for reasons based on their ready availability, but also on the basis of the fact that the resulting products are some of the most effective surface active agents within the scope of this invention. Because of their availability from natural sources, these starting materials provide products of low cost, available in essentially unlimited quantity.
Of the oxyalkylating agents, the preferred alkylene oxide which has the greatest water-solubilizing capacity and which yields detergent products not depleted or exhausted by adsorption is ethylene oxide. This material is a readily available article of commerce and is usable at oxyalkylating conditions readily attainable in the chemical process arts. In the preferred method of synthesis the initial starting material containing the active, oxyalkylatable hydrogen atom, such as the aforementioned preferred fatty acids and alkylphenols, and including the long chain alcohols (both natural and synthetic types), the long chain alkylamines and arylamines, and the alkylarylamines is initially condensed with an alkylene halohydrin or alkylene oxide such as ethylene chlorohydrin, or more preferably, ethylene oxide, to introduce the initial oxyalkylene unit, producing an intermediate condensation product containing an active hydroxyl group on the end of a single alkylene unit. This intermediate is then subjected to further oxyalkylation by condensation with an alkylene oxide, such as ethylene oxide, to introduce from 2 to about 19 additional oxyalkylene units and provide the intermediate poly-oxyalkylated condensation product. In the latter phase of the reaction, the alkylene oxide, such as ethylene oxide, is mixed with a basic catalyst (such as sodium ethylate, sodium hydroxide, soda ash, or other corresponding alkali metal derivative), followed by addinga sufficient quantity of alkylene oxide to the mixture to form a poly-oxy-alkene chain in which the number of oxyalkylene units per molecule corresponds to the value of m. in the foregoing formula. When ethylene oxide is utilized in the condensation reaction, the value of n in the above empirical formula for the product is 2, but if propylene oxide (generally less preferred) is involved in the condensation reaction, it has a value of 3. Further variety and flexibility in the properties of the resulting product is obtained by using a mixture of propylene and ethylene oxides or by alternate condensation of one alkylene oxide in the reaction followed by additional condensation with the other oxide.
Oxyalkylation to form the intermediate condensation effected initially with an alkylene oxide such as ethylene and/or propylene oxide, starting with the alkylphenol, alkylamine, etc. and subjecting the resulting mixture of starting material and alkylene oxide to oxyalkylation temperatures of from about 10 to about 100 C., at pressures suflicient to maintain the reaction mixture in essentially liquid phase. The. presence of an alkaline substance, such as an alkali metal hydroxide, alkali metal alcoholate or other catalyst in the reaction mixture also promotes the latter condensation. These reaction conditions are also suitable for elfecting oxyalkylation of the initial oxyalkylated product (for example, the p-re-intermediate product formed by condensing the starting material with a single mole of an alkylene halohydrin). The number of oxyalkylene units in the intermediate condensation product is determined generally by the molar ratio of alkylene oxide to pie-intermediate or starting material charged to the oxyalkylation reaction stage.
Following the completion of the intermediate oxyalkylation stage of the process in which the hy-drophilic polyoxyalkylene chain is introduced into the molecular structure, the terminal hydroxyl group at the end of the poly-, oxyalkylene chain is esterified with a polybasic acid containing from two to three carboxyl groups per molecule. Typical dibasic acids utilizable in esterifying the polyoxyalkylated intermediate include such acids as maleic acid, succinic, acid, adipic acid, oxalic acid,'glutaric acid, phthalic acid, salicyclic acid etc., or the correspondingacyl mono-halides and dibasic acid anhydrides, such as adipoyl bromide, succinoyl chloride, phthalic anhydride, etc. T ypical tribasic acids and acid anhydrides or acyl halides utilizable herein include trimellitic acid, trimesic acid, citric acid, etc., or their anhydrides, such as trimellitic acid anhydride:
which condenses with the hydroxyl group of the poly- (oxyalkylene) chain through the acidic carboxyl group. Generally, the acid halides are more readily condensed with the poly-oxyalkylated intermediate; the condensation usually occurs by mixing the respective reactants in a closed vessel at sutficient pressure to maintain the mixture substantially in liquid phase at the reaction temperature, which is maintained at from about 50 to about 150 C. General-1y, an equimolar ratio of the reactants is utilized, based upon a single carboxyl or acyl halide radical undergoing condensation with a. single hydroxyl group of the intermediate. Pressures of from atmospheric to 20 to 30 atmospheres are suitable, depending upon the volatility of the reactants. V
The ester formed by the condensation of one of the carboxyl groups of the polybasic 'acid reactant with the poly-oxyalkylated intermediate is thereafter neutralized, the remaining free carboxyl group( s) being reacted with a suitable base, such as sodium hydroxide, potassium hydroxide, ammonia, an alkylarnine, arylamine or alkanol amine, such as ethanolamine or diethanol-amine to form the corresponding alkali metal or ammonium salt. The resulting product is substantially neutral in aqueous solution M in the above empirical formula, representing the present products, may therefore be an alkali metal, ammonium, alkylammonium, alleanolammonium, arylam monium, etc., depending upon the choice of neutralizing agent for reaction with the dibasic acid condensation product.
In addition to the foregoing anionic and cationic surface active agents in the present detergent composition of 10 matter the latter may also contain a variety of additives having specific activity in aqueous solution when subsequently utilized for laundering detergent purposes. Thus, the composition may contain the usual builder salts, such as sodium sulfate, an alkaline earth metal water softener such :as a sodium polyphosphate, an anti-redeposition agent such as sodium carboxymethyl cellulose, whitening or brightening agents that arecolorless to the eye but are excited by ultraviolet light so that they fluoresce blue and thus make fabrics appear brighter or whiter, dry bleaches such as sodium peroxide, etc., as well as a variety of other detergent ingredients having known properties in detergent compositions.
Of the components having surface active properties present in the composition, it is generally preferred that the anionic detergent component constitute a major proportion of the combined surface active agents, preferably from about 50 percent to about percent of the combined surface active agents, with the remaining 5 percent to 50 percent consisting of the present cationic ingredient. These proportions are not critical in providing a detergent composition having the aforementioned properties, but provide compositions in which the maximum desirable properties are present, particularly the feel, or handle, of cotton fabrics laundered in an aqueous solution of the detergent composition. 7
Other embodiments of this invention and Specific illustrations of variables contemplated herein are exemplified in the following examples, which, however, are introduced for illustrative purposes only, with nojintention of limiting the scope of the invention necessarily in-accordance therewith.
Examplel A detergent composition comprising a mixture of an anionic detergent ingredient and a cationic surface active agent especially suitable as a laundering composition is prepared by mixing the surface active materials, hereinafter designated, with various additives which enhance the cleaning power of the composition for laundering cotton fabrics.
'Ammonyx G, a cationic'surfactant identified by its manufacturer (Onyx ChemicalCompany) as a quarternary ammonium salt formed by methylating a primary cetyl amine to give the cor-responding cetyl dimethyl amine, which in turn is then quaternized by the addition of benzyl chloride, is supplied as a 98 percent active paste and is used as the source of the cationic surfactant ingredient in the preparation of the present laundering composition. By itself, Ammonyx G, as an 0.3 percent aqueous solution at 140 F. has a detergency rating of about 15 percent of an equivalent sample of a built sodium dodecylbenzene sulfonate detergent composition in a standard Terg-O-Tometer comparison test using 40 cycles per minute. The Terg-O-Tometer employs a series of agitators to simulate the mechanical action of a house hold or commercial laundering machine and thus the test of detergency is similar to actual fabric washing conditions. The sample of standard detergent (rated at 100) used as a basis for comparison in the following tests is a spray dried mixture of 35 percent by weight of sodium dodecylbenzene sulfonate (a benzene-propylene tetramer alkylate sulfonated with oleum and neutralized with sodium hydroxide), 40 percent by Weight of sodium sulfate and 25 percent by weight of sodium tripolyphosphate. A detergency rating of 15 indicates that the ability of the sample detergent to remove soil from a cotton muslin swatch, as measured by the increase in reflectance of light from the soiled swatch before and after laundering in the detergent solution, is 15 percent of the ability of the standard sodium dodecylbenzene sulfonate detergent composition under equivalent test conditions, and at equivalent concentrations of detergent in the aqueous detergent solution.
Ammonyx G mixed with a wide variety of anionic surface active agents, including specifically, sodium dodecylbenzene sulfonate, a stearic acid soap, sodium lauryl sulfate, the sodium salt of a sulfated fatty acid, and a sulfated alcohol amide formed water-insoluble precipitates when aqueous solutions of the Ammonyx G and the individual anionic detergents were mixed, the detergency of the resulting aqueous filtrate being substantially the same as the detergency of the component in excess in the mixture.
Cotton fabrics laundered in an 0.3 percent aqueous solution of Ammonyx G possess a desirable lubricated quality, evidenced by a suedy feel and by a soft, smooth, drapy finish when the laundered fabric is brushed. This effect is retained by the laundered cotton fabric through repeated rinsings in clear water, the cationic component being retained on the surface of the textile by What is believed to be electrostatic attraction between the negatively charged hydroxyl radicals present in cellulose and the electropositive quaternary ammonium group of the surfactant. The dry fabric also possesses a desirable feel, characteristic of nylon and silk fabrics, after treatment with the Ammonyx G surfactant solution. Because of its substantivity to many fabrics and relatively low detergency, the latter cationic surface active agent cannot by itself serve as an effective surfactant for laundering cotton fabrics by the usual household laundering methods. Most cationic surface active agents, therefore, must be mixed with a non-ionic detergent having a substantially greater detergency to provide a composition having sufficient detergency to be effective in reasonable concentrations, but containing the cationic ingredient to take advantage of its textile treating properties in a laundering operation. Anionic detergents of the following structure:
are not only effective detergents, but are compatible in admixture with cationic detergents without formation of a precipitate and without depreciation of the detergency or the substantive textile softening effect of either surfactant ingredient of the resulting mixture.
The results which follow in Table I below are typical of several different species within the above generic class of the present anionic detergents, the individual species in the group varying with respect to detergency and solubility, depending upon the choice of radicals involved in the synthesis of the product. The results in Table I below are for several species of reactants which give rise to different standard classes of detergents. The description of the procedure for synthesizing the various species is similar, since each synthesis involves essentially the same mechanism. For the sake of simplicity of description, however, the procedure will be described for the preparation of one species Within the group encompassed by the foregoing structural formula, in which:
R=Nonylpheny1 X =Oxy 71-:2 m=Average of 6 y= M=Sodium It is to be emphasized, however, that in thus describing the procedure with respect to one specie, it is not thereby intended to limit the scope of the disclosure to such single specie; the procedure may be adapted to other species by nominal variations in temperature, proportions of ethylene oxide, and other reaction variables, as well as variations in charge stocks and technique. The anionic detergent represented by the above values of the variables in the foregoing empirical formula is prepared by oxyethylating nonylphenol, formed by alkylation of phenol with nonene-l in a preliminary synthesis, followed by condensing ethylene oxide with the isolated nonylphenol until the poly-oxyethylene chain contains the required number of oxyethylene units to average 6 for the species of product described in this preparation. The oxycthylated nonylphenol was then condensed in a subsequent reaction with succinoyl chloride and the remaining carboxyl group neutralized to the sodium salt by hydrolysis in the presence of caustic.
Nonylphenol was prepared by the alkylation of phenol with nonene-l (the trimer of propylene polymerized over a solid phosphoric acid catalyst at 350 F.) using anhydrous boron trifluoride as alkylation catalyst. Nonylphenol was separated from the alkylation reaction mixture as the fraction boiling from 296 to 304 C.
Nonylphenol was oxyethylated with ethylene oxide in the presence of sodium ethylate catalyst by mixing 8 molar proportions of liquid ethylene oxide with one molar proportion of nonylphenol and 0.6 percent by weight of the reaction mixture of sodium ethylate. The mixture is placed in a rotating autoclave, pressured to 5 atmospheres pressure with nitrogen and as the autoclave is rotated, the contents are maintained at 135 C. maximum (with cooling) until a drop in pressure indicates completion of the run. The contents of the autoclave, after cooling to room temperature, consists of poly-oxyethylated nonylphenol, an oily material which by cryogenic molecular weight determination, contains an average of about 6 oxyethylene units per molecule. Examination of the product indicates that substantially all of the ethylene oxide charged into the reaction entered into the product.
The above intermediate is condensed with succinoyl chloride to form the mono-carboxylate ester of the terminal hydroxyl group on the poly-oxyethylene chain by heating for 3 hours a molar excess of succinoyl chloride (estimated to be about 1.2 moles of succinoyl chloride per mole of oxyethylated nonylphenol) with the oxyethylated intermediate at C. (the temperature of a boiling salt Water bath surrounding the reaction flask containing the mixed reactants). Hydrogen chloride gas formed as the condensation reaction proceeds is taken overhead and absorbed in a caustic bubbler. Following the above reaction period, the reaction mixture is neutralized with sodium hydroxide and the remaining acid chloride hydrolyzed from the mono-carboxylate ester by the addition of 30 percent excess caustic to the reaction mixture and heating the latter at 110 C. for 1% hours. The sodium salt of the succinic acid ester product is precipitated as a solid by cooling the reaction mixture with a salt-ice bath, the desired product separating as a viscous oil which dissolves readily in warm or cold Water over a wide range of concentrationes. Aqueous solutions of the product produced a thick, stable foam when shaken and an 0.3 percent solution of the product at 140 F. has a detergency of percent solution of the sodium dodecylbenzene sulfonate composition, refered to above, used as standard in the Terg-O-Tometer detergency test procedure.
A mixture of 50 parts by weight of the sodium succinate ester of the poly-oxyethylated nonylphenol and 50 parts by weight of Ammonyx G (95 percent active paste) produced a surfactant composition which was completely water-soluble in F. water at concentrations of solid in Water up to and beyond 5 percent by weight.
The following Table I presents data concerning the relative detergency and fabric texture-inducing properties of several mixtures of Ammonyx G and the present anionic detergent component, varied with respect to several factors indicated in Table I. All mixtures contain the previously determined optimum percentage of 0.3 percent of detergent composition in an aqueous laundering solution at 140 F., using a Terg-O-Tometer as the test apparatus.
*Relative to 0.3 percent aqueous solution of the standard SDB'S detergent composition at 140 F.
TABLE I.PROPERTIES F MIXED ANIONIC-CATIONIC SURFACTANTS [Ammonyx G and the dihasic acid ester of a poly-oxyalkylated intermediate] Anionic Detergent Detergency, Cotton Percent of Texture Acid 1 in Detergent Type and No. Percent in Starting Material 4 Std. Quality of A20 2 Mixture 3 Succinic 50 Nonylphenol 6 68 3+ d0 88 4+ 109 3+ 115 3+ 120 4+ 128 5- 118 5 85 4+ 108 5- 105 3+ 119 5+ 103 5+ 99 5+ 103 5+ 110 6+ 86 5+ 111 5+ 125 5+ 1 Dibasic acid involved in formation of ester linkage.
2 A designates alkylene oxide: type selected from EtO (ethylene oxide) number of alkylene oxide units in polyoxyalkylene chain to form ester 1i and PrzO (propylene oxide); average nkage with dibasic acid.
3 Percent of anionic ingredient in mixture of combined anionic-cationic ingredients.
4 Compound involved in initial oxyalkylation to form intermediate product.
5 Cotton texture quality determined on 4 square yard piece of cotton muslin laundered in detergent solution; 5+ maximum degree of contribution to cotton texture with respect to softness, suppleness, and feel; 5- indicates minimum contribution to desirable texture; i.e., test muslin harsh to the touch, minimum suppleness; intermediate texturizing ability indicated between maximum at 5+ to minimum or negative ability at 5-.
6 Nonene-l alkylate of phenol as starting material.
' Propylene trimer alkylate of phenol as starting material' 8 Propylene tetramcr alkylate of phenol as starting material.
' Propylene tetramer alkylate of benzene used as starting material.
I claim as my invention:
1. A mixture of a cationic surface active agent having a quaternary ammonium radical and a hydrophobic hydrocarbon group and an anionic detergent consisting of a mono-alkali metal salt of a polybasic carboxylic acid mono-ester of the terminal alkylol group of a poly-oxyalkylated organic compound containing a hydrophobic hydrocarbon radical on the opposite end of the poly-oxy alkylene chain, said carboxylic acid containing from 2 to 3 carboxyl groups, the poly-oxyalklyene chain containing from about 2 to about 20 oxyalkylene units having from 2 to 3 carbon atoms per unit and said hydrophobic hydrocarbon radical contains from 8 to about 21 carbon atoms, the proportion of cationic surface active agent in said mixture being from about 5 to about 95 percent by weight.
2. A mixture of a cationic surface active agent having a quaternary ammonium radical and a hydrophobic hydrocarbon group and an anionic detergent of the structure: RX[(C H O) OC(CH COOM],, wherein R is a monovalent hydrocarbon radical containing from 8 to about 21 carbon atoms, X is selected from the group consisting of oxo, thio, carboxy and carboxamido, n is a whole number selected from 2 and 3, m is a whole number selected from 2 to about 20, M is an alkali metal, and y and a are Whole numbers selected from 1 and 2, the proportion of said anionic detergent being from about 5 to about 95 percent of the combined anionic and cationic ingredients of said mixture.
3. The composition of claim 2 further characterized in that R is an alkylphenyl group in which the alkyl radical contains from 8 to about 12 carbon atoms and X is oxy.
4. A mixture of a cationic surface active agent having a quaternary ammonium radical and a hydrophobic hydrocarbon group and the condensation product of a polyoxylalkylated alkyl phenol and a dibasic, d-icarboxylic acid containing from 3 to 4 carbon atoms per dibasic acid unit and characterized further in that said condensation product is an alkali metal salt of a mono-carboxylate ester of said poly-oxyalky1ated phenol, the proportion of cationic surface active agent in said mixture being from about 5 to about 95 percent by Weight.
5. The composition of claim 4 further characterized in that the oxyalkyl unit of said poly-oxyalkylated alkyl phenol is ethoxy and said condensation product contains from 2 to about 20 ethoxy units per poly-oxyalkylene chain.
6. The composition of claim 1 further characterized in that the proportion of cationic surface active agent to combined cationic and anionic surface active agents in said mixture is from about 10 to about 50 percent.
7. The composition of claim 2 further characterized in that said cationic surface active agent is a quaternary ammonium salt of a long chain alkyl-substituted dialkylamine.
8. The composition of claim 7 further characterized in that said long chain alkyl substituent is a cetyl group.
9. The composition of claim 8 further characterized in that said amine is substituted on the nitrogen atom of the amino group by dimethyl groups.
10. The composition of claim 1 further characterized in that said polybasic acid mono-ester is the mono-ester of succinic acid.
11. The composition of claim 1 further characterized in that said polybasic acid mono-ester is the mono-ester of malonic acid.
References Cited UNITED STATES PATENTS LEON D. ROSDOL, Primary Examiner.
ALBERT T. MEYERS, JULIUS GREENWALD,
MAYER WEINBLATT, Assistant Examiner.
UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,345,300 October 3, 1967 Henry C. Speel It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.
In the heading to the printed specification, line 8, for "Dec l0 1952" read Dec 1O I962 Signed and sealed this 15th day of October 1968.
EDWARD J. BRENNER Edward M. Fletcher, Jr.
Commissioner of Patents Attesti ng Officer