US2298696A - Detergent composition - Google Patents

Description

Patented Oct. 13, 1942 UNITED STATES PATENT OFFICE" 2,29s,s9s

DETERGENT COMPOSITION Jay C. Harris, Dayton, Ohio, assignor to Monsanto Chemical Company, St. Louis, Mo., a corporation of Delaware No Drawing.

Application December 2, 1940,

Serial No. 368,225

8 Claims.

The present invention relates to improved detergent compositions of high efliciency adapted for a very wide range of uses, comprising an alkylated aromatic sulfonic acid or a water-soluble salt thereof, and a combination of a plurality of inorganic salt detergent builders.

It is known that alkylated aromatic sulfonic acids and. the alkali-metal salts thereof. have The art also application is a continuation-in-part, I have dis-,

closed detergent compositions comprising alkylated aromatic sulfonic acids in which the alkyl group or radical contains more than eight and less than sixteen carbon atoms, and watersoluble salts thereof, used in combination with sodium sulfate or a similar detergent builder which is a water-soluble inorganic salt of an alkali metal, and magnesium sulfate or magnesium chloride. The present application includes several additional specific detergent compositions conforming to the general type disclosed in my prior copending application.

I have found that if the alkylated aromatic sulfonic acid or alkali-metal salt of the specified type is combined with sodium sulfate or a similar neutral inorganic salt detergent builder and magnesium sulfate or magnesium chloride in certain definite proportions that a composition having improved lathering and deterging power is obtained and that the surface and interfacial tensions of such compositions are lower than that of the pure alkylated aromatic sulfonic acid derivative. The improved detergent-compositions of the present invention correspond approximately to the following general formula of a typical composition in which the alkylated aromatic sulfonic acid is an alkylated benzene sulfonic acid:

35% to 65% by weight of alkylated benzene sulfonic acid in which the alkyl group contains from 9 to 15 carbon atoms, and preferably from 11 to 15 carbon atoms, or an alkalimetal salt thereof,

0.5% to 4.0% by weight of hydrated magnesium sulfate (Epsom salt) or equivalent amounts of anhydrous or hydrated magnesium chloride,

65% to 35% by weight (less the small proportion of magnesium sulfate or chloride used) of anhydrous sodium sulfate, which can be partially replaced by sodium carbonate up to about equal parts by weight of sodium carbonate and sodium sulfate.

The magnesium sulfate or chloride in the preferred compositions of this invention corresponds to approximately 3% to 25% of that quantity required stoichiometrically to convert the alkylated aromatic sulfonic acid or salt completely to magnesium salt. A preferred range within the above range is 40% to 60% of alkylbenzene sul fonate to 60% to 40% ,(less magnesium compound) of sodium sulfate and the same proportion of magnesium compound as above specified.

Examples of typical preferred compositions conforming to the foregoing general formula are as follows:

EXAMPLE 1 The following are mixed by grinding:

Parts by weight A mixture of sodium salt of dodecylbenzene and tridecylbenzene sulfonic acids 40 Anhydrous sodium sulfate 58. 5 Hydrated magnesium sulfate (Epsom salt)- 1.0 EXAMPLE 2 The following are mixed by grinding:

Parts by weight A mixture of sodium salt of dodecylbenzene sulfonic acid and tridecylbenzene sulfonic acids 40 Anhydrous sodium sulfate....; 38.5 Anhydrous sodium carbonate (soda ash)- 20 Hydrated magnesium sulfate (Epsom salt) 1 EXAMPLE 3 The following are mixed by grinding:

Parts by weight A mixture of sodium salts of dodecyl and tridecylbenzene sulfonic acids Anhydrous sodium sulfate 60 Anhydrous sodium carbonate 40 Hydrated magnesium sulfate (Epsom salt) 4 EXAMPLE 4 The following are mixed by grinding:

Parts by Weight The sodium salt of a dodecylbenzene sul- EXAMPLE The following are mixed by grinding:

Parts by weight The sodium salt of a dodecylbenzene sulfonic acid 40 Anhydrous sodium sulfate 58 Hydrated magnesium sulfate (Epsom salt) 2 EXAMPLE 6 The following are mixed by grinding:

Parts by weight fonic acid Anhydrous sodium sulfate Sodium carbonate Hydrated magnesium sulfate (Epsom salt) 4 EXAMPLE '7 The following are mixed by grinding:

Parts by weight The sodium salt of a mixture of dodecylbenzene and tridecylbenzene sulfonic acids 100 Anhydrous sodium sulfate 100 Hydrated magnesium sulfate (Epsom salt)- 2 Instead of grinding, the compositions may be prepared in more homogeneous form by dissolving the constituents in water or other solvent and thereafter recovering the composition in solid form by evaporation or like procedure. When preparing the compositions in this manner from hard water, consideration must be given to the mineral content of the water used.

Further specific examples of the improved compositions of the invention are exemplified by the detergent compositions used in the tests which follow:

SURFACE TENSION A solution containing 1% by weight of a purified dodecylbenzene sodium sulfonate was dissolved in pure distilled water. The surface tension of such solution at 0., as measured on the Du Nouy tensiometer, was 36.5 dynes per cm;

Pure dodecyl- Concentration of solution benzene sodi- Example 1 Example 2 um sulfonate Neither sodium sulfate nor magnesium sulfate when used separately or together have any substantial effect on surface tension or lnterfaclal tension of water when used at these dilutions. When used in conjunction with a constant amount of alkylbenzene sodium sulfonate, magnesium sulfate decreases the surface tension slightly, sodium sulfate also decreases the surface tension slightly, but the mixture of the two in the proportions specified herein produces a greater decrease than the same amount of either magnesium sulfate or sodium sulfate when used alone. Also, at such dilutions, a mixture of sodium sulfate and magnesium sulfate in the proportions specified herein when partially substituted weight for weight for alkylbenzene sodium sulfonate actually decreases the surface tension of the solutions. Partial substitution of sodium sulfate or magnesium sulfate separately weight for weight for alkylbenzene sodium sulfonate produces slight lowering of surface tension. This lowering of surface tension is much less than that produced by a mixture of magnesium sulfate and sodium sulfate in the proportions specified herein when partially substituted for alkylbenzene sodium sulfonate in the same manner.

INTERFACIAL TENSION The surface tension between purified hydrocarbon oil (Nujol) and the solutions used in the surface tension tests hereinabove were measured at 25 C. by means of the Du Nouy interfacial tensiometer. The interfacial tensions in dynes per cm. at 25 C., as thus measured, were as follows:

Pure dodocyi- Conccntration of solution benzene sodi- Example 1 Example 2 um sulfonate LATHERIN G AND DETERGENCY TESTS In these tests the water used was a soft water containing a determined hardness of 25 parts or 50 parts per million (P. P. M.) as calcium carbonate unless otherwise indicated.

A purified dodecylbenzene sodium sulfonate was used in the tests.

The lathering test was conducted by dissolving the specified amount of the particular detergent composition in cc. of water, warming the solution to F., and placing the solution in a pint jar containing ten small rubber balls and thereafter agitating the jars and their contents under identical conditions of agitation for 10 minutes while maintaining the solution at 140 F. At the end of this period the agitation is stopped and the height of the suds or lather in the jar is measured. The values of lather are expressed in inches of height in the pint jar. This test is conveniently conducted in conjunction with the detergency test.

The detergency test was conducted as follows:

A standard soil is prepared by depositing a suspension of colloidal graphite mineral oil, and Wesson oil in carbon tetrachloride upon six-inch wide strips of desized muslin or similar cotton fabric. After a suitable aging interval (about days) the strips of soil are cut into six-inch squares and segregated according to depth of soil, utilizing a Universal photoelectric photometer (Pfaltz & Bauer). Only swatches of the same depth of shade are used for test.

The detergent test is made in a Launderometer at 140 F. For anygiven detergent composition two swatches are used. These are placed in separate pint Mason jars and ten rubber balls are added to each. One hundred (100) ml. of detergent solution at a temperature of 150 F. are then transferred to each jar, and the jar is then capped and placed in the Laun erometer maintained at 140 F. and are rotat d therein for minutes. At the end of this period the jars are removed, the swatches recovered from the used detergent solution, which is discarded, and a 1 inch strip of fabric removed from each swatch. The remainder of the strip (4 x 6" in size) is returned to the bottle, ten rubber balls are added, fresh detergent solution (100 ml.) is transferred thereto and another 10 minute wash interval made. Another 1 /2 inch strip is then removed. washes are made.

The duplicate strips from the 10, 20, and minute wash periods are rinsed in water of the same hardness as employed in the wash and the strips are allowed to dry.

The strips are then measured for soil removal with the Universal photoelectric photometer using as means for comparison a strip of unsoiled white fabric (100% white) and a swatch of standard soilv of the same depth of black as that used in the test (0% white) swatches represent varying degrees of whiteness resultant from the washing procedure. The duplicate readings-from all four washes are arithmetically averaged to yield a value representing average percentage soil removal.

In these tests the relative detersive eificiencies represent a comparison related to washing with a 0.2% solution of dodecylbenzene sodium sulfonate in soft water having a hardness of 25 P. P. M. as calcium carbonate, which is rated as 100.0%. a

I Table I Lather and relative detersive efiiciency of do decylbenzene sodium sulfonate in soft water having a hardness of P. P. M. as calcium carbonate at various concentrations were as follows:

Detcrsive Concentration, per cent emciency.

Lather Inches None can be produced by the use of dodecylbenzene,

sodium sulfonate alone is 1 inches. It is to be noted that at 0.20% concentration the height of lather is only inch.

In the same way two more 10 minute The washed Table II The effect on the later and relative detersive efficiency of solutions of dodecylbenzene sodium sulfonate in soft water having a hardness of 50 P. P. M. as calcium carbonate which is produced a by addition of anhydrous sodium sulfate is as follows. The solutions all contained 0.2% of mixture of sodium sulfate and dodecylbenzene sodium sulfonate and the "per cent sodium sulfate" in the first column represents the amount of sodium sulfate which was substituted for dodecylbenzene sodium sulfonate in the particular mixture.

Relative Percent sodium sulfate Lather detersive ollicicncy Inches Per cent 0 lmfi l0 A 103. 6 )4 102. 3 1, 4 96. 5 2% 95. 3 3 97. 7 3 95. 3 3 92.9

This indicates that the height of lather can be. increased by the addition of increasing amounts of sodium sulfate but that the maximum height which can be obtained is 3 inches. Furthermore, the addition of a small amount of sodium sulfate increases the relative detersive efficiency of the dodecylbenzene sodium sulfonate but beyond this small amount the detersive efiiciency decreases.

Table III Relative detersive efficiency Mg salt added, percent conversion Lather Inches Percen! The effect of the addition of magnesium chloride to dodecylbenzene sodium sulfonate is sim ilar to that of the addition of sodium sulfate, namely, small amounts increase the amount of lather and detersive efiiciency to a certain extent but after maximum lather is obtained the detersive efficiency of the composition drops with further additions.

Table IV The effect on the lather and relative detersive efiiciency produced by the addition of mixtures of anhydrous sodium sulfate (A) and hydrated magnesium sulfate (B), to dodecylbenzene sod1um sulfonate (C) at 0.2% concentration (of the three-component mixture) in soft water having a hardness of 50 P. P. M. as calcium carbonate is as follows. The compositions of the mixtures are represented as parts by weight of the three components which are referred to as A, B and C, as above, from which the percentage compositions can be calculated, if desired.

Mixture (garts by weig t) Relative Lather detersive cilicicncy A B Inches Percent 0 0 100 M 100.0 25 0 75 l 99 50 0 50 2 98 25 1.6 75 3 98 50 1.0 50 3 95 58. 5 1.0 40 4 95 nesium sulfate when used as the sole detergent,

builder (Table III) will increase lather without substantial decrease in detersive efficiency within the limits of 25% conversion of alkylated aromatic sulfonate to magnesium salt, and sodium sulfate when used as the sole detergent builder '(Table II) will increase lather without substantial decrease in detersive efiiciency, the use of sodium sulfate alone will not produce optimum lather and magnesium sulfate when used alone with the alkylbenzene sulfonate will increase lather but will not act as a substitute for the alkylbenzene sodium sulfonate since detersive efficiency decreases the smaller the percentage of alkylbenzene sodium sulfonate in the composition. The use of the plurality of builders, sodium sulfate and magnesium sulfate, within the respective limits of proportions specified and illustrated in the tables, actually produces optimum lather and maintains detergency of the alkylbenzene sodium sulfonate although the content of alkylbenzene sodium sulfonate in the composition is reducedby more than half. Actually, therefore, the sodium sulfate acts as a substitute for alkylbenzene sodium sulfonate, weight by weight (as is apparent from results in Tables I and. II) since it enhances that portion of the detersive emciency which can be attributed to the alkylbenzene sodium sulfonate itself (Table I).

.The unexpected effect of the combination of the magnesium sulfate and sodium sulfate with the alkylbenzene sodium sulfonate is also apparent from the surface tension and interfacial tension values which are shown hereinabove.

Table V In the following table is illustrated the relative ineifectiveness of other heretofore wellknown detergent builders in producing lather and their relative detersive efficiencies when used with dodecylbenzene sodium sulfonate. In all these compositions the percent salt, as indicated in the first column, represents the percentage which was used in admixture with the dodecylbenzene sodium sulfonate. The mixtures were used in solutions containing 0.2% of the particular mixture in soft water having a hardness of 50 P. P. M. as calcium carbonate.

Relative Percent salt added Lather dctersive Inches None g 100. 0 10% sodium carbonate. 97. 8 25'7 sodium carbonate. M 97. 8 40 a sodium carbonate 1 100.0 10% trisodium phosphate 54 98.8 257 trisodium phosphate. 36 98.8 40 o trisodium phosphate $4 97.8 10% disodium phosphate. 97.0 25% disodium phosphate. y, 100. 0 40% disodium phosphate... 93. 7 10% tetrasodium phosphate 5 91. 6 25% tetrasodium phosphate. M 93. 7 40% tctrasodium phosphate. $4 93. 7 10% sodium scsquicarbonate. 36 97.0 25% sodium scsquicarbonate 93. 7 40% sodium sesquicarbonate $6 97. 8

Although the foregoing illustrative results are directed largely to those obtained with dodecylbenzene sodium sulfonate they are typical of results obtained with alkylated aromatic hydrocarbon sulfoni'c acids in which the alkyl group contains from 9 to 15 carbon atoms and particularly 11 to 15 carbon atoms and their watersoluble salts, particularly the sodium and other alkali-metal salts of alkylated aromatic sulfonic acids of the benzene series.v The principles of the invention are especially applicable to the formulation of detergent compositions containing the various isomeric undecyl, dodecyl, tridecyl, tetradecyl, and pentadecyl-substituted ben- "zene, toluene, xylene and other sulfonic acids of the benzene series and their salts or mixtures thereof, such, for example, as are described in the patent to Lucas P. Kyrides, Number 2,161,- 174. The products described in said patent are essentially mixtures of alkali-metal salts of mono-sulfonated, mono-alkylated benzene compounds obtained by introducing chlorine into an excess of a kerosene fraction consisting substantially of parafiin hydrocarbons, the major proportion of which is selected from the group consisting of undecane, dodecane, tridecane, tetradecane and pentadecane and having a distilling range of substantially 182 C. to 280 C., so as to produce a preponderant proportion of alkyl monochlorides, employing said alkyl monochlorides as an alkylation medium by condensing a substantial molecular excess, based on the alkyl monochlorides present, of an aromatic hydrocarbon of the benzene series therewith to obtain substantially monoalkylated benzene compounds, sulfonating said monoalkylated benzene compounds and converting the sulfonic. acids to alkalimetal salts.

Inasmuch as the foregoing description comprises preferred embodiments of the invention, it is to be understood that the invention is not limited thereto and that modifications and variations can be made therein, as is understood in the art, without departing substantially from the invention which is to be limited solely by the appended claims.

I claim:

I. A detergent composition consisting of a mixture of the following substances in approximately the following proportions by weight per parts by weight of the composition: (1) 35 to 65 parts of a substance selected from the group consisting of monoalkyl-substituted benzene, toluene and xylene sulfonic acids, the substituted alkyl groups of which contain at least 9 and less than 16 carbon atoms and alkali-metal salts thereof.

together with (2) a magesium compound selected from the group consisting of magnesium sulfate and magnesium chloride in a proportion equal to approximately 3% to 25% of that amount required stoichiometrically to convert all the alkyl-substituted aromatic sulfonic acid compound in the composition to magnesium. salt, and (3) anhydrous sodium sulfate in a proportion equal to 35 to 65 parts diminished by the amount of magnesium compound present.

2. A detergent composition consisting of a mixture of the following substances in approximately the following proportions by weight per -100 parts by weight of the composition: (1) 35 to 65 parts of a sodium salt of a monoalkylated benzene sulfonic acid, the alkyl group of which contains at least 9 and less than 16 carbon atoms,

' (2) 0.5 to 4.0 parts of hydrated magnesium sulfate, and (3) anhydrous sodium sulfate in a proportion equal to 35 to 65 parts diminished by the amount of magnesium compound present.

3. A detergent composition comprising the following substances in approximately the following proportions by weight: 40 parts of a mixture of dodecylbenzene and tridecylbenzene sodium sulfonates, 58.5 parts of anhydrous sodium sulfate and 1 part of hydrated magnesium sulfate.

4. A detergent composition consisting of the following substances in approximately the following proportions by weight: 100 parts of the sodium salts of a mixture of dodecylbenzene and tridecylbenzene sulfonic acids, 100 parts of anhydrous sodium sulfate, and 2 parts of hydrated magnesium sulfate.

5. A detergent composition consisting of the I parts diminished by the amount of magnesium dium sulfonates, 38.5 parts of anhydrous sodium sulfate, parts of anhydrous sodium carbonate and 1 part of hydrated magnesium sulfate.

7. A detergent composition consisting of the following substances in approximately the following proportions by weight: 100 parts of the sodium salts of a mixture of dodecylbenzene and tridecylbenzene sulfonic acids, 60 parts of anhydrous solium sulfate, 40 parts of anhydrous sodium carbonate and 4- parts of hydrated magnesium sulfate.

8. A detergent composition consisting of a mixture of the following substances in approximately the following proportions by weight per 100 parts by weight of the composition: 1) 35 to 65 parts of a detergent comprising essentially a mixture of alkali-metal salts of monosulfonated, monoalkylated benzene compounds obtained by introducing chlorine into an excess of a kerosene fraction consisting substantially of paraffin hydrocarbons, the major proportion of which is selected from the group consisting of undecane, dodecane, tridecane, tetradecane and pentadecane and having a distilling range of substantially 182- C. to 280 C., so as to produce a preponderant proportion of alkyl monochlorldes, employing said alkyl monochlorides as an alkylation medium by condensing a substantial molecular excess, based on the alkyl monochlorides present, of an aromatic hydrocarbon of the benzene series therewith to obtain substantially monoalkylated benzene compounds, sulfonating said monoalkylated benzene compounds and converting the sulfonic acids to alkali-metal salts, together with (2) a magnesium compound selected from the group consisting of magnesium sulfate and magnesium chloride in a proportion equal to approximately 3% to of that amount required stoichiometrically to convert all the sulfonated alkylated benzene salt in the composition to magnesium salt, and (3) anhydrous sodium sulfate in a proportion equal to to compound present.

JAY C. HARRIS.