US3565949A - Diaminoalkanediylidenetetraphosphonic acids useful in cleaning compositions - Google Patents

Abstract

CLEANSING COMPOSITIONS ARE DESCRIBED CONTAINING A SYNTHETIC ORGANIC DETERGENT AND AS A BUILDER THEREFOR A DIAMINOALKANEDIYLIDENETETRAPHOSPHONIC ACID.

Description

United States Patent O US. Cl. 260502.5 3 Claims ABSTRACT OF THE DISCLOSURE Cleansing compositions are described containing a synthetic organic detergent and as a builder therefor a diaminoalkanediylidenetetraphosphonic acid.

BACKGROUND OF THE INVENTION (A) Field of the invention This invention relates to cleansing compositions and in particular to detergent compositions having builder ingredients for augmenting the cleansing action of the detergent.

(B) Description of the prior art In the cleansing art it is well-known that the efficacy of soap or detergent is considerably improved by the presence of certain supplementary substances commonly referred to as builders. While the benefits derived from such entities are widely appreciated, the mechanism by which they increase detergency has never been fully elucidated. Very likely several phenomena come into play thereby greatly complicating the formulation of any single theory to account for the behavior of builders. This is lent credence when it is realized that detergency itself is highly complex in nature involving many factors. Among those believed to have some effect on built detergency systems are stabilization of solid soil, emulsification of soil particles, the surface activity of the aqueous detergent solution, solubilization of water insoluble materials, foaming or suds forming characteristics of the washing solution, peptization of soil agglomerates, neutralization of acid soil and sequestration of mineral hardening constituents present in the washing solution. Other less well defined and understood factors also may exert some influence. Since no general rule is known which enables one to predict Whether a particular substance is capable of performing as an overall detergency builder, resort must be had to a great deal of empirical testing and investigation of candidate materials.

Among the known builders, representatives may be found which are of the organic and inorganic types. Examples of the latter are the water-soluble inorganic alkaline salts as typified by alkali metal carbonates, borates, phosphates, polyphosphates, bicarbonates, silicates and the like. Examples of the former are alkali metal, ammonium and substituted ammonium aminopolycarboxylates as represented by sodium and potassium ethylenediaminetetraacetate, sodium and potassium N-(2-hydroxyethy1)- ethylenediaminetriacetate, sodium and potassium nitrilotriacetate, sodium, potassium and triethanolammonium-N- Patented Feb. 23, 1971 ice (Z-hydroxyethyl)nitrilodiacetate as well as the alkali metal salts of phytic acid, e.gt, sodium or potassium phytate, etc.

Although generally satisfactory, the builder materials utilized heretofore suffer from certain limitations and disadvantages. Even the most widely accepted group of builder materials, the so-called condensed inorganic polyphosphates such as the alkali metal tripolyphosphates, are not without their shortcomings. Such compounds, the most common of which is sodium tripolyphosphate, exhibit a propensity when used in detergent compositions, of hydrolyzing into less condensed derivatives having diminished builder properties. In fact these less condensed products, which include orthoand pyro-phosphates, may form undesirable precipitates in the aqueous washing solution.

As the need for detergent builders has grown and expanded, more attention is being given to the development of new and improved members of this class of cleanser adjuncts.

SUMMARY OF THE INVENTION It has now been discovered that excellent builder characteristics can be realized by the use of certain organo-phosphorus acids collectively referred to as diaminoalkanediylidene-tetraphosphonic acids wherein two phosphono groups and one amino group are attached to each terminal carbon atom of the alkanediylidene, and the provision of cleansing compositions containing them in combination with a water-soluble non-soap synthetic detergent surfactant as well as the preparation and use of such compositions constitutes the principal object and purpose of the invention. Other objects and purposes will become apparent in the ensuing description.

DESCRIPTION OF THE INVENTION AND THE PREFERRED EMBODIMENTS The diaminoalkanediylidenetetraphosphonic acid builder materials herein can be depicted by the following general formula wherein A is a 2-6 carbon alkylene bridge which may be centrally interrupted by oxygen or sulfur and R is a hydrogen or lower hydroxyalkyl such as HOCH HOCH CH HO(|JHCH2-, HOCH-CH, etc.

CH3 CH3 CH3 As understood herein a lower hydroxyalkyl means that the hydrocarbon moiety may contain from l-S carbon atoms.

As can be seen from an inspection of the formula, the builder materials of the present invention have a molecular structure in which two phosphono groups and one amino group are attached to the terminal carbon atoms of a saturated hydrocarbon bridge optionally interrupted by sulfur or oxygen. According to Chemical Abstracts, a saturated hydrocarbon bridge having two unsatisfied valences on each of its terminal carbon atoms is referred to as an alkanediylidene radical and can be illustrated by the formula Where the connecting alkanediylidene bridge contains no interrupting oxygen or sulfur atoms, the resulting compounds are known chemical entities and are described in the technical literature. They are obtained by reacting phosphorus trihalides with organic nitriles. The reaction is carried out at temperatures between about C. and 100 C. using about two moles of phosphorus trihalide per mole of the nitrile. Either during or after the reaction, an organic acid, such as glacial acetic acid or oxygen-containing inorganic acid such as phosphorus acid, are added. After this treatment, the product is hydrolyzed with water to generate the free acids; or the monoor di-esters are produced by reaction with suitable alcohols or phenols, preferably in the presence of acid-binding agents. A detailed description of these organophosphorus compounds, including their preparation, is given in British Pat. No. 995,462.

Certain of the compounds falling within the ambit of Formula I have not been previously described and these can be represented by the following configuration:

RNR RNR wherein R has the significance as above set forth, and n is an integer of 1-3. These patentably new entities can be realized by condensing a phosphorus trihalide, orthophosphorous acid and a bis( terminally substituted cyano-alkyl) sulfide or ether. After the initial exothermic reaction had subsided, a slightly elevated temperature was maintained for a time interval sufficient to complete the reaction. After hydrolyzing, the products were isolated in the form of white solids. They may be purified by dissolving in a base and reprecipitated by acidification.

The builder materials herein are all hexabasic acids having a total of 8 protons, two of which are held by the amino groups, thereby forming inner salts. The pK values of the fifth and sixth protons ranged from 5.7, for the six carbon chain, and 5.9 for the seven carbon chain. However when an oxygen or sulfur atom is interposed in the alkylene chain, the pK values are 9.1 and 9.4 respectively. Thus, the tetraphosphonic acids containing an interrupting hetero atom in the alkylene bridge, provide buffering in a region which is particularly desirable for detergent builder applications. Thus our new diaminoalkanediylidenetetraphosphonic acids, containing an inter.- rupting hetero atom, constitute a sub-class which are more effective detergent builders than the general category of this type of organophosphorus acids.

Among the detergent surfactant compounds, whose cleansing power is enhanced by the diaminoalkanediylidenetetraphosphonic acids of the invention are the following categories and examples:

(1) Anionic Synthetic Detergents.These may be designated as Water-soluble salts of organic sulfuric reaction products having in their molecular structure an alkyl or acyl radical of carbon atom content within the range of about 8 to about 18 in a sulfonic acid or sulfuric acid ester radical. Included are sodium or potassium alkyl benzene sulfonate in which the alkyl group contains about 9 to about carbon atoms in either a straight chain or a branched chain; sodium and potassium alkyl glyceryl ether sulfonates, especially those ethers of higher fatty alcohols derived from the reduction of coconut oil; the reaction product of higher fatty acids with sodium or potassium isothionate, where, for example, the fatty acids are derived from coconut oil; sodium or potassium alkyl sulfonates and sulfates especially those alkyl sulfates derived by the sulfation of coconut or tallow fatty alcohols and mixtures of such alkyl sulfates, dialkyl esters of sodium or potassium salts of sulfosuccinic acid, for example, the dihexyl ester; sodium and potassium salts of sulfated or sulfonated monoglycerides derived, for example, from coconut oil, sodium or potassium salts of the higher fatty alcohol esters of sulfo-carboxylic acids, for example, the sodium salt of the lauryl alcohol ester of sulfo-acetie acid; sodium or potassium salts of a higher fatty acid amide of methyl taurine in which the higher acyl radicals, for example, are derived from coconut oil; and others known in the art, a number being specifically set forth in U.S. Pat. 2,486,921, issued to Byerly on Nov. 1, 1949. Examples of other useful anionic non-soap synthetic detergents are acyl sarcosinates, e.g., sodium N-lauroyl sarcosinate.

(2) Nonionic Non-Soap Synthetic Dete-rgents. These may be broadly classed as being constituted of a watersolubilizing polyoxyethylene group in chemical combination with an organic hydrophobic compound such as polyoxypropylene, alkyl phenol, the reaction product of an excess of propylene oxide and ethylenediamine, and aliphatic alcohols. The nonionic synthetic detergents have a molecular weight in the range of from about 800 to about 11,000.

One well-known class of nonionic detergents is made available on the market under the trade name of Pluronic. These compounds are formed by condensing ethylene oxide with a hydrophobic base formed by the condensation of propylene oxide with propylene glycol. The molecular weight of the hydrophobic base is of the order of 1,500 to 1,800. The addition of polyoxyethylene radicals to this hydrophobic base increases the water solubility of the entire molecule. Liquid products are obtained up to the point where the polyoxyethylene content is about 50% of the total weight of the condensation product; higher proportions of polyoxyethylene renders the products solid in consistency. The molecular weights of Pluronic L61, L64 and L68, for example, are approximately 2,000, 3,000 and 8,000 respectively.

Examples of other nonionic synthetic detergents useful in the present invention are: condensation products of 6 to 30 moles of ethylene oxide with one mole of an alkyl phenol containing 6 to 12 carbon atoms, either in a straight or branched chain, in the alkyl group (e.g., nonyl or octylphenol); condensation products of 6 to 30 moles of ethyl- .ene oxide with one mole of an aliphatic straight chain or branched chain alcohol containing 8 to 18 carbon atoms (e.g., lauryl alcohol or tallow fatty alcohol); condensation products of ethylene oxide and the reaction product of propylene oxide and ethylene diamine wherein the reaction product has a molecular weight of 2,5003,000, for example, and the condensation product has a polyoxyethylene content of 40% to The builder materials of the invention are compatible with the usual cleansing composition additives and in this connection mention is made of such common adjuncts as bactericidal additives, fillers such as sodium carbonate and sodium sulfate, excipients such as sodium stearate and vegetable fats, optical brighteners, anti-redeposition agents such as carboxymethylcellulose, dyes, pigments, dedusters such as mineral oil, foam stabilizers, tarnish inhibitors, ammonium chloride as 'well as the other known builder materials such as the condensed phosphate, e.g., tripolyphosphate, pyrophosphates and the like. The builder material herein also admits the inclusion of bleach agents in the detergent or cleanser compositions such as the chlorinated cyanuric acids, chloramine-T and similar bleaching agents.

Generally speaking, the ratio of detergent surfactant to the builders of the invention can vary over wide limits although the usual ratio ranges from about 20:1 to about 1:20 where no other builders are present. When used in combination with other builder materials such as sodium tripolyphosphate or in special cleansing formulations, the ratio of detergent surfactant to the builders of the invention can vary from about 1:100 to about :1.

The diaminoalkanediylidenetetraphosphonic acids herein possess a number of characteristics which render them excellent materials for use as detergent builders. One such property is their excellent metal sequestering and chelating ability, the compounds being superior in this respect to the builder most commonly used at present, namely, sodium tripolyphosphate. The metal sequestering abilities of the builder materials herein are summarized in Table 1; the chelate stability ratings in Table 2. Comparison data also are given for sodium tripolyphosphate and some typical organic builders.

6 bridge, Massachusetts. Magnesium sequestering capacities were determined by titration with 0.1 M. magnesium acetate solution to a potentiometric endpoint using a divalent TABLE 1 (RHO P-gCAC(P03HR) sequestering capacity (25 0.,

pH 10) (gram ions metal/mole) RNR RNR A R Ca++ Mg+ Cu Mn++ (A) Compounds of the invention:

(1) CH2CH2SCH2CH2 H 3. 5 3. 2 2. 1 3. 7 (2) -CH2CH2OCI'I2CH2 H- 3. 2. 1 (3) -(OH2)5 H 3. 4 3. 4 2.0 3. 6 (4) -(CH2) H- 2. 9 (CH2)4 HOOH2CH2 1. 7

(B) Compounds of the prior art:

Sodium tripolyphosphate (STPP) 1. 0 1. 2 1. 2 1. 2 Nitrilotn'acetic acid (NTA) 1.0 0. 9 1. 3 2. 7 Aminomethylenediphosphonic acid (AMDP) 1. 5 1. 6 1. 2 1. 8 Nitrilotrimethylenephosphonic acid (Dequest) 0.7 0. 9 1. 2 1. 5

As Tables 1 and 2 show, the presence of sulfur or oxygen in the alkanediylidene bridge increases the watersolubility of the alkaline earth metal chelates of the tetraphosphonic acids.

Calcium sequestering capacities of the tetraphosphonic acids vary with pH in the range from 9 to 11. Thus, Compound 1 exhibits increased sequestering capacity as the pH changes from pH 9 to pH 11 while compound 3 shows a 3% decrease over the same range. In contrast, the calcium sequestering capacity of a typical organic builder, aminomethylenediphosphonic acidAMDP-increases by 50% over the pH range 9 to 11.

Raising the temperature from C. to 50 C. has little effect on the magnesium sequestering capacity of STPP and AMDP although it increases the magnesium sequestering capacity of compound 3 by 14% and the capacity of compound 1 by 22%.

Calcium and magnesium chelate stabilities of the tetraphosphonic acids calculated from metal sequestering capacities determined by divalent ion electrode/oleate indicator methods described elsewhere herein were found, where measurable, to be sufficiently high to maintain calcium and magnesium ion concentrations low enough for good detergent building.

ion electrode made by Orion Research, Inc. Cupric copper and manganous manganese sequestering capacities were determined by titration with 0.1 M. cupric sulfate or manganous acetate solution to a visual endpoint. Hydroxyl ion was the precipitant in both instances.

The effectiveness of the compounds herein in reducing calcium and magnesium ion concentrations is determined by the chelate stability constants of the respective metal ions. The calcium and magnesium chelate stability constants given in Table 2 were ascertained from the metal ion sequestering capacities using the electrode and oleate methods and the solubility product of the metal oleate.

(metal chelateY +A l ll l K mstabrhtypK instability=log K instability Solubility product of metal oleate 1'7 33 From which [M++] can be calculated given TABLE 2 (RHO P -C-AC(PO3HR) Calcium Magnesium chelate chelate RNR RNR stability stability (pK in- (pK in- A R stability) stability) (A) Compounds of the invention:

(1) CH2CH2SCH2CH2 H (i. 8 6. 3 (2) CHgCH OCH CH2 II- 6.0 6.1 2)s (i) 6.4 (4) (CH2)4- H- (1) (5) (CH2)4- HOCHQCH 5.0

(B) Compounds of the prior art:

Sodium tripolyphosphate (SIPP) 5. 4 5. 8 Nitrilotriacetic acid (NTA) 6. 2 G. O Aminomethylenediphosphouic acid (AMDP) 5. 9 5. O Nitrilotrimethylenephosphonic acid (Dequest) (z) 5. 4

1 Chelate too insoluble to allow measurement. 2 Stability too low to measure.

The aminoalkanetetraphosphonic acids are hexabasic, two of the total of 8 protons being held by the amino groups forming inner salts. The pK values of the fifth electrode chelate capacity-oleate chelate capacity oleate chelate capacity The data of Table 2 show that the alkanediylidenetetraphosphonic acids are capable of maintaining calcium and magnesium ion concentrations lower than is possible with sodium tripolyphosphate.

Reference is now made to the following non-limiting examples.

Example 1 Adiponitrile (10.8 g., 0.10 mole) and 52.2 g. (0.6 mole) of orthophosphorous acid were charged into a 250 ml., 3-necked, round-bottomed flask fitted with a mechanical stirrer, thermometer, additional funnel and cal cium chloride drying tube. To the mixture was added with stirring 111.0 g. (0.41 mole) of phosphorus tribromide over a seven-minute period. An exotherm occurred causing the temperature to rise to 44 C. over the next twenty minutes. The reaction temperature was maintained at 4550 C. for a total of 4.5 hours by means of a heating bath. The reaction mixture, which was now a talfy-like mass, was slowly quenched with 120 ml. of water with stirring resulting in a temperature rise to 90 C. A white precipitate which formed during the hydrolysis was separated by filtration at C., washed with several portions at acetone and vacuum dried at 100 C. to give 7.0 g. of white solid, M.P. 234262 C. The solid gave a negative test for orthophosphate.

Neutralization Equivalent: 478.Theory is 472. Equivalence points were obtained at pH 4.1 and 7.9 corresponding to pK values of 2.9, 5.7 and 5.7.

Pimelonitrile (36.6 g., 0.30 mole) and 156.6 g. (1.90 moles) orthophosphorous acid were charged into a 500 ml. reactor fitted as described in Example 1. To the mixture was added with stirring 333.0 g. (1.23 moles) of phosphorus tribromide over a seven-minute period. The reaction mixture was held at 40-50 C. for 7 hours and at 25 C. for 64 hours. The reaction mixture was diluted with 165 ml. of Water resulting in a clear solution. Dilution of the solution with 2,000 m1. of acetone caused the product to precipitate. It was recovered by filtration, 'washed with acetone and vacuum dried to give 71.3 g. of crude product. Purification of the crude by dissolution in 10% sodium hydroxide and reprecipitation by acidification with 10% hydrochloric acid gave 29.2 g. of white solid, M.P. 245-257 C.

Neutralization Equivalent: 461.Theory is 450. Equivalence points were obtained at pH 4.2 and 8.1 corresponding to pK values of 2.9, 5.9 and 5.9.

Bis(2-cyanoethyl) sulfide (200 g., 1.43 moles) and 748 g. (9.13 moles) orthophosphorous acid were charged into a 3,000 ml. reactor fitted as described in Example 1. To the mixture was added with stirring 1,580 g. (5.93 moles) of phosphorus tribromide. The reaction mixture was held at 50-60 C. for 6 hours and diluted with 600 m1. of water. The resulting clear, yellow solution was vacuum stripped on a rotating evaporator to give a sirup. Dilution of the sirup with 1,000 ml. of denatured ethyl alcohol caused a solid to precipitate which was collected on a filter, washed with acetone and vacuum dried to give 384 g. of crude product. The crude product was purified by dissolution in 10% sodium hydroxide and precipitation by acidification with 10% hydrochloric acid. The solid after separation, washing with acetone and drying weighed 71.3 g., M.P. 220239 C.

Neutralization Equivalent: 476.Theory 486. Equivalence points were obtained at pH 3.8, 7.6 and 10.5 corresponding to pK values of 2.4, 5.6 and 9.4.

Bis(Z-cyanoethyl) ether (25 g., 0.20 mole) and g. (1.28 moles) orthophosphorous acid were charged into a 250 ml. reactor fitted as described in Example 1. To the mixture was added with stirring 224 g. (0.82 mole) phosphorous tribromide. The reaction mixture Was held at 40-50 C. for 30 hours and at 25 C. for hours. Dilution with 120 ml. of water gave a clear yellow solution which was vacuum stripped yielding a sirup. The sirup was diluted with 5,000 ml. of acetone to precipitate product which was recovered by filtration, Washing with acetone and drying to give 23.9 g. of white solid, M.P. 127- Neutralization Equivalent: 450.-Theory 452. Equivalence points were obtained at pH 4.0, 7.4 and 10.5, corresponding to pK value of 2.3, 5.8 and 9.1.

Example 5 Detergency tests.The subject materials were tested for building properties and compared with STPP, NTA and AMDP using a detergency test developed by Spangler, Cross and Schaafsma, I. Am. Oil Chem. Soc., 42, 723 (1955). Test conditions were: Hardness and 300 p.p.m.; total detergent concentration 0.15%; temperature 120 F.; pH 9.5. The active material was sodium linear alkylarylsulfonate (Sulframin 85, Ultra Div. Witco Chem. Co.). Detergent formulation compositions were:

Percent by weight Active material 20.0 Sodium metasilicate S-hydrate 12.0 Carboxymethyl cellulose (CMC) 0.5 Builder 50.0 Sodium sulfate Balance The tests were run in a Tergotometer on fabric specimens soiled with a synthetic natural-type soil. The results, given in Table 3 below, are average final percent reflectance readings of fabric specimens after 3 soilings and 3 washes. Water of 150 p.p.m. hardness was used for rinsing. Active material to builder ratio was 20/50. The results show that the tetraphosphonic acids are close to the best of the known builders as represented by STPP, NTA and AMDP in builder eifectiveness under the conditions used.

l Expressed as percent of sodium tripolyphosphate (STPP) standard. Anionic surfactant; Surfactant/Builder: 20/50 and 20/25; concentration: 0.15%; 120 F.; pH 9.5; Hardness, 150 p.p.m. and 300 p.p.m.

From an inspection of the data reported in the tables, it is at once evident that the alkanediylidenetetraphosphonic acids of the invention have several advantages over sodium tripolyphosphate which is the detergent builder now commonly used. It is particularly significant to note that the compounds herein are orders of magnitude more hydrolytically stable and thus do not lose their metal sequestering ability over extended periods of time and at elevated temperatures; they have a capacity for sequestering calcium which exceeds that of sodium tripolyphosphate by a factor of 3 on a weight basis (some members are capable of maintaining the calcium and magnesium ion concentration lower than is possible with sodium tripolyphosphate). It is generally believed by those in the art that this is an important factor in detergency;

they exhibit appreciably better sequestering capacity for calcium, magnesium, copper and manganese ions than sodium tripolyphosphate or nitrilotriacetic acid and their calcium and magnesum chelate stability constants generally exceed those of sodium tripolyphosphate or nitrilotriacetic acid.

It is to be understood that the alkanediylidenetetraphosphonic acid builders of the invention include and encompass the free acids per se as well as the ammonium and alkali metal salts as exemplified by their ammonium, trimethylammonium, triethylammonium, dimethylamrnonium, lithium and potassium salts. Those skilled in the art will select that form of the builder herein which best suits their particular detergent formulation and needs.

Pursuant to the requirements of the patent statutes, the principle of this invention has been explained and exemplified in a manner so that it can be readily practiced by those skilled in the art, such exemplification including what is considered to represent the best embodiment of the invention. However, it should be clearly understood, that, within the scope of the appended claims, the invention may be practiced by those skilled artisans having the benefit of this disclosure otherwise than as specifically described and exemplified herein.

What is claimed is:

1. A compound of the formula NHz NH;

wherein X is oxygen or sulfur and n is 1 to 3.

2. The compound of claim 1 wherein the formula is 3. The compound of claim 1 wherein the formula is FOREIGN PATENTS 1,171,401 6/1964 Germany 260-5025 LEON ZITVER, Primary Examiner I. E. EVANS, Assistant Examiner US. Cl. X.R.

UMTED STATES PATENT OFFICE CERTEFICATE OF CORRECTION Patent No. 3 5 5 9"9 Dated February 3, 1971 Inventor(s) Richard Williamson Cummins It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Col. 3, Formula II, that portion of the formula reading (PO3HR)n should read (PO HR) Col. 7, Example 3, that portion of the formula reading (PO H should read (PO H Col. 7, Example '4, that portion of the formula reading (POZHZ )2 should read (PO HZ 2 G01 8, line 21 "(1955)" should read --(l965)-- Col 8, line 57 "acid" should be omitted Col 9, Claim 1 that portion of the formula reading {0H) should read (CH Col. 10, Claim 3, that portion of the formula reading Should read Signed and sealed this 18th day of April 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents