US3370100A - Detergent alkylate compositions - Google Patents

Description

Feb. 20, 1968 G. JWM EWAN 3,370,100

DETERGENT ALKYLATE COMPOSITIONS Original Filed June 19, 1965 ACTUAL EF FECT IMPROVEMENT PtATES WASHED PREDICTED EFFECT I I I 0% 25 5O 75 IOO% TRIMER IOO% 75 50 V 25 0% DIMER INVENTOR GILBERT J. Mc EWAN ATTORNEY United States Patent Free EQTQJGQ Patented Feb. 20, 1968 ABSTRACT OF THE DISCLOSURE octadecyl benzene, mono-octadecyl toluene, and mono-- octadecyl xylene wherein the octadecyl portion of said mono-octadecyl aromatic hydrocarbon contains from about 9 to about 15 methylene groups and having branching on from about to about 50% of their alpha carbon atoms; the weight ratio of said monododecyl aromatic hydrocarbon to said mono-octadecyl aromatic hydrocarbon in the mixture being from about 1:4 to about 4:1, respectively.

This application is a division of my application Ser. No. 288,976, filed June 19, 1963 and now US. Patent 3,311,563. The present invention relates to detergent compositions and to methods and materials for their manufacture. More particularly, the present invention relates to novel, synergistically active compositions which contain mixtures of certain alkylbenzene sulfonates and have unexpectedly valuable detergent properties, and'to novel compositions useful for the manufacture of these synergistically active compositions.

At present, by far the majority of the detergents that are sold to the consuming public contain alkylbenzene sulfonates or other alkyl aromatic sulfonates as their major detergent active ingredient. The alkylaromatic sulfonates presently utilized and sold commercially derive their alkyl substituents, to a very large extent, from olefin polymers. The most commonly used olefin polymers for this purpose are propylene tetramers, propylene pentamers, and fractions intermediate between these two.

Alkylaromatic sulfonates that are derived from conventional polypropylene olefins, however, have alkyl chains that are highly branched; particularly at the alpha-carbon atom. For example, sodium dodecylbenzene sulfonate, which is prepared by alkylating benzene with tetrapropylene and subsequently converting the resulting alkylbenzene to the sulfonate, contains a very high proportion of material having a tertiary a-carbon atom, i.e., an alpha carbon atom connected to three alkyl carbon atoms, as in Formula 1. (1) 1 NaOsSCsH4C3R2 (R R and R in Formula 1 each contain an alkyl carbon atom connected directly to the a-car'oon atom). These materials are generally significantly less biodegradable than are otherwise similar alkylaromatic sulfonates that are derived from olefins that are less highly branched (or more straight-chain) in character than are the conventional polypropylene olefins, for example,

where the a-carbon atoms are connected directly to at most two, and sometimes to only one alkyl carbon atom; 1

NaOaSCoH4(,3Rz

Consequently, where quick biodegradiability of alkylaromatic sulfonate detergents is desired or required, it is generally preferred that detergent compositions containing alkylaromatic sulfonates that have more of a straightchain character (than do the alkylaromatic sulfonates made from conventional tetrapropylene) be utilized.

One class of these more biodegradable alkylaromatic sulfonates is manufactured utilizing a hexene dimer which in turn has been made from a hexene selected from the group consisting of hexene-1, hexene-2, and hexene3 hexenes. (The numerical designation after the word hexene indicates the position in the n-hexene molecule at which the double bond occurs. For example, hexene-2 can be represented by the Formula 4-:

(4) H H H H H H while hexene-3 can be represented by the Formula 5:

(5) H H H H H H HOCC=CCOH.)

H H H H Both hexene-2 and hexene-3 occur in 2 isomeric (cis, trans) forms. Although dimers of these preferred hexenes can be prepared by several well-known methods, one of the best methods whereby they can be made in a relatively pure form is via the process described in the co-pending United States patent application, Ser. No. 126,859, 'filed July 26, 1961, now abandoned, assigned to the same assignee as the present patent application; which process comprises agitating internally unsaturated hexene under pressure and in the presence of a Friedel- Crafts type catalyst.

Alkylaromatic sulfonic compounds that are manufactured from such hexene dimers, however, have the apparently inherent shortcoming of being somewhat inferior in certain of their surface active properties to the best grades of otherwise comparable conventional alkylaromatic sulfonates made from certain polypropylene olefines. For example, aqueous solutions of sodium, potassium, or other alkali metal salts of these hexene dimer benzene sulfonates generally have significantly less ability to maintain a high, stable, aqueous foam and to clean various solid substrates in the presence of dissolved greases than do aqueous solutions of the best of the sodium and potassium polypropylene benzen sulfonates. In a standard test designed to closely examine the suitability of various water-soluble surface active agents (surfactants) for use in the formulation of high foaming hand dishwashing detergents sodium dodecylbenzene sulfonate made from hexene dimer cleaned about 10 plates before the foam or lather on the surface of the test solution broke, while a total of 22 plates could be etfectively washed by a detergent containing a sodium mono higher alkylbenzene sulfonate derived from conventional pentapropylene (the best performer in this test derived from polypropylene known to date) before the lather broke. (This test will he described in more detail below.)

It has now been found that the ability of the alkali metal hexene dimer mono higher alkylaromatic sulfonates to produce and maintain a high stable foam in the presence of greasy soils can be greatly enhanced by utilizing them in combination with appropriate amounts of a compound having a structure like that of an alkali metal hexene trimer mono higher alkylaromatic sulfonate.

Actually, the invention is believed all the more surprising because compounds having structures like the alkali metal hexene trimer mono higher alkylaromatic sulfonates are, themselves, not particularly outstanding surfactants.

It should be emphasized at this point that the term hexene dimer as used herein in conjunction with such terms as mono higher alkylaromatic, mono higher alkyl benzene, benzene, and the like is intended to be indicative solely of the type of structure of the higher alkyl portion of the particular mono higher alkylaromatic compound being discussed. Thus, the use of hexene dimer herein does not necessarily mean that the compound was derived by dimerizing hexene, although the compound could very well be manufactured in this way. The essential property of the hexene dimer materials encompassed by this invention is their chemical structure. Thus, any material which has a structure like those compounds which can be manufactured by dimerizing hexene-l, hexene-Z, and/or hexene-3 (under conditions which do not result in excessive rearrangements of the-molecules during and after their dimerization, such as those conditions under which Friedel-Crafts dimerizations are conventionally accomplished) can be utilized in the practice of the present invention. Similarly, the term hexene trimer as used herein is intended to encompass those compounds having structures like those which result from trimerizing hexene-l, and is not intended to be limited solely to those materials made from hexene-l. A more definitive discussion of the actual chemical structures of the hexene dimer and hexene trimer compounds contemplated to be within the scope of the present invention will be presented hereinbelow.

It will also be readily appreciated by those in the art that the hexene dimer and hexene trimer mono higher alkyl aromatic materials referred to specifically herein are not necessarily pure materials, but are rather generally mixtures of materials having similar molecular weights, the average molecular weight of such mixtures being the ones desired and discussed specifically herein as though the materials were fairly pure.

In accordance with the present invention, it has been found that compositions containing alkali metal hexene dimer rnono higher alkylaromatic sulfonates and alkali metal hexene trimer mono higher alkylaromatic sulfomates in weight ratios, respectively, of from about 1:4 to

about 4:1, have greatly improved detergency characteristics when they are dissolved in water, as compared with aqueous solutions of the pure materials. Preferred weight ratios ofthese materials in such compositions are from about 7:13 to about 13:7, respectively.

the same assignee as the present patent application; and

subsequently sulfonating and neutralizing the resulting hexene trimer mono higher alkylaromatic intermediate compound. The term mono higher alkyl aromatic is herein intended to encompass those compounds having a single six membered aromatic hydrocarbon nucleus (or ring) and a single higher alkyl side chain attached to the ring through a C-C bond. The term higher alkyl is intended to include saturated alkyl chains containing from about 8 to about 30, and preferably from about 10 to about carbon atoms per higher alkyl chain. How- 4 ever, because of the particular subject matter of this invention, generally the term higher alkyl as used herein will be directed to compounds having either about 12 or about 18 carbon atoms. in addition to the single higher alkyl chain, the mono higher alkyl aromatic compounds encompassed .by this invention can also have attached to the aromatic nucleus from 1 to 4 lower alkyl groups, each containing from 1 to 4 carbon atoms, although a preferred class of mono higher alkyl aromatic compounds includes specifically the mono higher alkyl benzenes, toluenes, and xylencs. Of these, the mono higher alkyl benzenes are particularly preferred. The compositions and processes of the present invention will be particularly concerned herein with the preferred mono higher alkyl benzenes, toluenes, and xylenes, as well as their corresponding alkali metal sulfonatcs. For purposes of the present invention, the term alkali metal encompasses the ammonium (NI-1 cation as well as sodium, potas sium, lithium, rubidium, cesium, and francium. Of these, ammonium, sodium, and potassium are generally preferred because of their relatively low cost.

As it was mentioned heretofore, the alkali metal mono hexene dimer aromatic sulfonates to which this invention is directed are those having structures like the compounds that can be derived by dimerizing hexene-l, hexene-Z, or hexane-3, or mixtures thereof. These materials have a single higher alkyl chain that contains, on the average, about 12 carbon atoms. The fact that the higher alkyl (dodecyl) portion of a particular dodecylbenzene, for example, has the desired structure (rather than that of one derived from conventional sources of dodecyl alkyl groups) can be ascertained via recognized analytical techniques. Some of these techniques will be described in greater detail herein subsequently.

The alkali metal mono haxene trimer aromatic sulfonates of this invention (in which the higher alkyl chain averages C has a structure like those derived by trimerizing hexene-l, hexene-Z, l1exene-3, or mixtures thereof. It, too, can be distinguished from conventional C alkylaromatic sulfonates by means of conventional analytical techniques. For example, by employing a recognized nuclear magnetic resonance (n.m.r.) technique in which, by means of a Varian Model A-60 spectrometer with spinning 5 mm. bore glass sample tubes at ambient temperatures (about 32 C.), and using tetramethylsilane as a standard, recording peak positions in cycles per second and ppm. of the magnetic field, it is possible (by subsequently comparing the areas under the respective peaks" in the n.m.r. spectra) to distinguish with fairly high accuracy the minimum number of methylene (--Cl-lg) groups in a given alkylaromatic hydrocarbon or its corresponding sulfonate sample. Thus, for the preferred mono hexcne dimer alkylaromatic compounds that are useful in the present invention it has been found that the minimum number of Cl-I groups or units is between about 6.0 and about 9.0, while the percent fraction. of molecules in the mono hexene dimer aromatic compounds of this invention that have branching on the a-carbon atom is be-.

tween about and about 50%, and is preferably between about 35 and about 46%. These figures are. to be compared with similar data for dodecylbenzene, for example, derived from conventional tetrapropylene. which has at most about 5.6 -CH groups per molecule and more than 65% of its molecules having branching on the a-carbon atom. Corresponding data for alkylbenzene prepared by alkylating benzene with conventional n-dodecene-l shows the minimum number of -CH groups equal to 9.8 and essentially no branching on the ot-carbon atom. The hexene trimer mono higher alkylaromatic hydrocarbons and thei'r corresponding sulfonates that are contemplated to be within the scope of this invention contain from about 9 to about 15 methylene groups. The percent fraction of molecules in these materials that have branching onthe a-carbon atom is from about 5% toabout 50%, and preferably is from about 5% to about 35%, ac-

cording to the n.m.r. analysis. Thus, since they have such a relatively high proportion of their carbon atoms in the form of methylene (-CH groups, the higher alkyl portion of the hexene dimer and hexene trimer mono higher alkylaromatic hydrocarbons (and their corresponding sulfonates) of this invention can be said to be largely straight chain in character.

The unexpected synergistic results that can be obtained by practicing the present invention is illustrated by the drawing. A study of the drawing reveals that, whereas data (resulting from the use of a standard test involving the cleaning of synthetically soiled dinner plates using the individual relatively pure ingredients) indicates that it would be expected that a mixture consisting of a blend of an amount of sodium hexene dimer benzene sulfonate (in this instance derived from hexene-2) with an equal amount, by weight, of sodium hexene trimer benzene sulfonate (in this instance derived from hexene-l) would wash about 14 plates, it was found that the actual number of plates that could be washed with such a mixture was about 27. Similarly, a mixture consisting of 75 weight percent of the same sodium hexene dimer benzene sulfonate and weight percent of the same sodium hexene trimer benzene sulfonate successfully Washed about 25 plates, although from the plate Washing data for the pure individual ingredients of this mixture in this test, the mixture would be expected to successfully wash only about half this many plates.

The standard hand dishwashing test mentioned above involves the washing by hand of nine-inch dinner plates which are pre-soiled with one teaspoonful each of a synthetic soil mixture consisting of 75 Weight percent of shortening and 25 weight percent of flour. Washing of the plates is performed (using a dishcloth to remove the synthetic soil) in 4 liters of Water having an initial temperature of about C. and containing 0.075 weight percent of the surfactant or surfactant mixture being tested. The number of plates washed (for the data above, and in the drawing) is determined by the number of plates which can be cleaned in the normal fashion by the time the lather on the surface of the dishpan has broken to the extent that less than half of the surface remains covered with lather. The manipulative procedures of this test are described in greater detail in the Proceedings of the 43rd Annual Meeting of the Chemical Specialties Manufacturers Association, December 1956; Procedure No. 3, page 191.

While the valuable synergistic properties of the surfactant compositions of the present invention are most evident when these compositions are utilized (in aqueous media) in the presence of greases, these compositions are nevertheless also useful as general purpose detergents, dispersing agents, wetting agent, and the like, even in the absence of greases. For example, they can be advantage ously utilized in combination with any materials that can ordinarily be utilized in combination with any conventional alkali metal tetrapropylene-derived aromatic sulfonates, [such as sodium tetrapropylene (dodecyl) benzene sulfonate]. Such materials are well-known in the art and need not be detailed here. The surfactant compositions of this invention can also be advantageously used in combination with alkali metal tetrapropylene alkylaromatic sulfonates, if desired. The following data is illustrative of the broad ranges of applicability, as well as the high degree of utility in various types of applications, which the surfactant compositions of this invention have.

In Table I, a composition containing 50 Weight percent of sodium hexene dimer benzene sulfonate (wherein the hexene dimer was made by dimerizing a blend of hexene-2 and hexene-3) and 50 weight percent sodium hexene trimer benzene sulfonate (wherein the hexene trimer was manufactured by trinierizing hexene-1 in the presence of aluminum chloride), is compared in equal concentrations (in water) in the various standard tests shown With a commercial sodium pentadecylbenzene sulfonate (made Concen- Product Conven- Test tration of this tlonal (weight invention Surfacpercent) taut 1 Detergency 2 0.25 118 116 Ross-Miles Lather 3 0. 1

l6. 7 19. 7 10. 2 5. 9 17 8.4 (seconds). 33 24 0.031 79 47 Surface Tension 4 (dyues/cm.) 0. 25 27.8 30.1 10 26. 3 30. 6 0. 05 25. 7 31. 0 Interfacial Tension 4 (dynes/cm.) 0. 25 1. 2 6. 2 0. 10 1. 1 6. 1 0. 05 1. 0 6. 6 Spreading Coelficient 4 0.25 +2.1 -4. 2 0. 10 +2. 3 5. 6 0. 05 +5. 2 5. 2

Sodium dodecylbenzene sulfonate derived from conventional tetrapropylene (highly branched).

2 In 300p.p.m. hard water. Test described by Jay C. Harris in Evaluation of Surface Active Agents ASTM Bulletin, May, 1946.

3 50 0. Values were taken 5 minutes after the lather was formed.

4 Room temperature, in distilled water.

' One method for manufacturing the surfactant mixtures or blends of this invention is by simply intermixing one of the aforementioned alkali metal mono hexene dimer benzene, toluene, or xylene sulfonates than can be used in the practice of this invention with an appropriate alkali metal mono hexene trimer benzene, toluene, or xylene sulfonate such as those delineated hereinbefore in such proportions that one of the valuable synergistic mixtures of this invention result therefrom; for example, by blending an amount of potassium mono hexene dimer toluene sulfonate (made from hexene-2) with an equal amount, by weight, of potassium mono hexene trimer toluene sulfonate (made from hexene-l); by preparing a mixture consisting of 50 weight percent of ammonium mono hexene dimer benzene sulfonate (made from hexene-3), and 50 Weight percent of sodium mono hexene trimer toluene sulfonate (made from hexene-1) or blending 67 parts by weight of sodium mono hexene dimer xylene sulfonate (made from a blend of hexene-2 and hexene- 3) with 33 parts by weight of one of the desired sodium mono hexene trimer benzene sulfonates.

Another convenient Way in which the valuable surfactant mixtures of this invention can be manufactured is via a mixed 'alkylation procedure such as that illustrated below in the example.

Example A mixture consisting of 1670 parts by weight of hexene dimer (prepared from a mixture of hexene-1, hexene-2, and hexene-3, by following procedure described in Example I of US. patent application. Ser. No. 126,859, referred to above), and 2510 parts by weight of hexene trimer (prepared from hexene-1 by following the procedure described in Example I of US. patent application, Ser. No. 152,655, also referred to above) is added drop- Wise over a period of about 1 hour to 10,000 parts -by Weight of dry benzene which has previously been saturated with gaseous HCl, and which also contains dispersed therein, 130 parts by Weight of powdered aluminum chloride. During the addition of the hexene dimer-hexene trimer mixture, the temperature of the reaction mixture is held between about 35 C. and about 37 C. The reaction mixture is also continuously agitated during said addition. Agitation is continued after said addition for about 15 minutes or until the reaction (alkylation) is practically complete. The resulting reaction mass is then allowed to separate into two layers; and upper alkylated layer and a lower catalyst complex layer. The upper alkylated layer is then recovered and Washed thoroughly with Water and then fractionally distilled in vacuo. Fractional distillation, at about 2 mm. mercury vacuum yields weight percent of desired product boiling between about I 95 and about 175 C., based on the total amount of hexene dimer-hexene trimer mixture initially charged into the benzene. The product from the distillation is an approximately equimolar mixture of hexene dimer benzene and hexene trimer benzene.

Sultonation of the resulting product from the foregoing distillation is accomplished by charging 2000 parts by weight of the mixture of 'alkylbenzenes into a conventional glass-lined reaction vessel, lowering the temperature of the mixture to about C., and then adding, dr'opwise, 2500 parts of oleum with constant agitation. During the addition of the oleum, the temperature of the sulfonation reaction mass is maintained below about 20 C. After all of the oleum is added, the reaction mass is agitated for an additional hour while the temperature of the reaction mass is permitted to rise to 40 C; Then 200 parts of water are added. After an additional 10 minutes of agitation, during which time the temperature Within the reaction vessel is below about C., the agitation is halted and the mixture permitted to settle into two layers. The lower spent sulfuric acid layer is discarded, while the upper layer is recovered and found to be an approximately equimolar mixture of mono hexene dimer benzene sulfonic acid and hexene trimer benzene sulfonic acid. The mixture of sulfonic acids is subsequently neutralized with a 50 weight percent aqueous solution of sodium hydroxide in a conventional manner to yield one of the valuable synergistic surfactant mixtures of the present invention.

While the foregoing example was of necessity restricted to the manufacture of an equimolar mixture of sodium mono hexene dimer benzene sulfonate with sodium mono hexene trimer benzene sulfonate, such an overall procedure can be utilized to manufacture practically any of the surfactant mixtures of this invention.

The procedure described in the foregoing example represents perhaps the most economical and practical manner in which the present invention can be practiced. For example, mixtures or blends of an approprate hexene dimer with an appropriate hexene trimer (in the same or similar molar or weight ratios as they appear in the surfactant mixtures of this invention) and/ or mixtures or blends of the: monohexene dimer benzene, toluene or xylene with the monohexene trimer benzene, toluene or xylenes to which the present invention is directed (in approximately the same molar or weight ratio as they appear in the final surfactant mixtures of the invention) can readily be sold to detergent manufacturers, who in turn can convert the various intermediate mixtures into the final surfactant mixtures for use in their own detergent products. Thus, blends or mixtures of hexene dimer with hexene trimer made from hexene-1, hexene-2, and/ or hexene-3 (in weight ratios of from about 80:20 to about 20:80, respectively, and preferably from about 13:7 to about 7:13, respectively) and/or blends or mixtures of the corresponding mono hexene dimer benzene, toluene, or xylene with mono hexene trimer benzene, toluene, or xylene (in similar Weight ratios), which are valuable intermediate compositions useful in the preparation of the final surfactant mixtures of this invention, and which also represent articles or materials likely to be sold in commerce in the practice of the invention, also constitute preferred maintained embodiments of the present invention. The followingspecific examples are illustrative of these preferred intermediate compositions.

25% hexene trimer.

75% hexene trimer.

40% hexene trimer.

25% hexene trimer benzene. hexene trimer benzene. 25% hexene trimer toluene. 65% hexene trimer toluene. 50% hexene trimer benzene. 25% hexene trimer xylouc. hexene trimer benzene. 75% hexene trimer toluene. 50% hexene trimer xylene. 50% hexene trimer toluene.

XIII. XIV 50% hexene dimer benzene.

1 Percentages given are weight percentages. In each example, hexene dimer and hexene trimer can be made from either pure hexene-1, hexene--, or hexene-3, or mixtures thereof, or by any other means whereby compornds having structures like those derived from these hexenes can be ma e.

Mixtures of the sulfonic acids corresponding to the mixtures of alkali metal mono hexene dimer aromatic sulfonates with. alkali metal mono hexene trimer aromatic sulfonates which were described hereinbefore as being: Within the scope of the present invention are also preferred embodiments of the invention.

What is claimed is:

1. An intermediate composition comprising a mixtureof a mono dodecyl aromatic hydrocarbon selected from the group consisting of monododecyl benzene, mono dodecyl toluene, mono dodecyl xylene, wherein the dodecyl portion of said mono dodecyl aromatic hydrocarbon con tains from about 6 to about 9 methylene groups and has. branching on from about 25% to about 50% of its alpha carbon atoms, and a mono octadecyl aromatic hydrocarbon selected from the group consisting of mono octadecyl benzene, mono octadecyl toluene, and mono octadecyl xylene, wherein the octadecyl portion of said mono octadecyl aromatic hydrocarbon contains from about 9 to about 15 methylene groups and has branching on from about 5% to about 50% of its alpha carbon atoms; the weight ratio of said mono dodecyl aromatic hydrocarbon to said mono octadecyl aromatic hydrocarbon in said mixture being from about 1:4 to about 4: 1, respectively.

2. An intermediate composition as in claim 1, wherein the weight ratio of said mono dodecyl aromatic hydrocarbon to said mono octadecyl aromatic hydrocarbon in said mixture is from about 7:13 to about 13:7, respectively.

3.. An intermediate composition as in claim 2, wherein said mono dodecyl aromatic hydrocarbon is mono dodecyl benzene and said mono octadecyl aromatic hydrocarbon is mono octadecyl benzene.

References Qited UNITED STATES PATENTS 2,712,530 7/1955 Baumgartner 252-161 2,944,023 7/1960 Stayner 260-671 2,972,583 2/1961 Hewitt 260671 DELBERT E. GANTZ, Primary Examiner.

C. R. DAVIS, Assistant Examiner.

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