US2980625A - Dispersions of benzimidazolylstilbene whitening and brightening agents and production thereof - Google Patents

Description

Un ed S tes DISPERSIONS F BENZIMIDAZOLYLSTEBENE WHITENING AND BRIGHTENING AGENTS AND PRODUCTION THEREOF Nathan N. Crounse, Cincinnati, Ohio, assignor to Sterling Drug Inc., New York, N. a corporation of Delaware No Drawing. Filed May 11, 1959, Ser. No. 812,121

Claims. (Cl. 252-152) This invention relates to the production of compositions comprising certain water-insoluble benzimidazolylstilbene whitening and brightening 7 agents and higher fatty acid amides or alkanolamides, to the compositions thus obtained, and to the use of said compositions in the preparation of detergent compositions having whitening and brightening properties. I The incorporation of relatively small amounts of fluorescent whitening and brightening agents into watersolublesynthetic organic anionic detergents intended for use in laundering is now a common practice. This procedure is of course quite simple when whitening and brightening agents have suitable water-solubility are em ployed, since conventional mixing and dispersing procedures of the detergent art readily afford homogeneous aqueous compositions, which if desired can be dried in the usual fashion, as by spray-drying. However, when substantially water-insoluble fluorescent whitening and brightening agents are involved, there arises the problem of obtaining uniform and satisfactory dispersion of the relatively small quantity of the fluorescent agent in the detergent as reflected inthe recovery of the full dyeing. strength. While it is frequently possible to dissolve the water-insoluble fluorescent agent in one of the usual liquid organic solvents, such as an a alcohol, ketone, or hydrocarbon, and thus facilitate its uniform incorporation into the detergent, toxicity and explosion hazards may be encountered with such solvents. Moreover, because of handling problems, some detergent manufacturers prefer not to receive the Whitening and brightening agent in the form of a liquid prepartion, preferring instead to receive and handle solid materials. ,In- Crounse US. Patent 2,838,5 0,4,'issued June 10, 1958, there are described benzimidazolylstilbene whitening andbn'ghtening agents, certain of which have the structural formula ii example methyl, ethyl, n-propyl, isobutylg'a'nd n-hexyl;

1 hydroxyl-lower alkyl containing 2-6 carbon at'oms, for

example Z-hydroxyethyl and 2,3-dihydroxypropyl; 2 -hydroxy-B-sulfopropyl; hydroxy-oxaalkyl containing 3-15 \carbon atoms, forexample- 2-hydroxy-3-(2,3-dihydroxypropoxy) propyl, 2-hydroxy-3- (Z-hydroxyethoxy) -propyl and 2 hydroxy 3 [2-(2-hydroxyethoxy)'ethoxy]propyl; carboxy-lower alkyl containing 2-6 carbon 'ato rns for example icarbox ymethyl and Z-carboxyethyl; cyano-lower alkyl containing 3-6 carbon atoms, for example 2-cyano- Patented Apr. 18, 1961 ice ' benzyl, 2,4-dichlorobenzyl, and meta-bromobenzyl, lower alkylbenzyl such as ortho-methylbenzyl and para-isopropylbenzyl, and lower alkoxy-benzyl such as p methoxybenzyl and 3,4-diethoxybenzyl, as well as 2-chloro-4- methoxybenzyl, 3-methoxy-4-rnethylbenzyl, 2-methoxy-4- chloroben'zyl, and the like; at least one of the radicals Y vand Y being other than hydrogen. In general, the

compounds of Formula 1 above are high-melting yellow or green-yellow solids which are substantially insoluble inwater. v .5

It is an'object of the instant invention to provide novel andimproved means for facilitating the uniform dispersal of relatively small proportions by weight of the waterinsoluble benzimidazolylstilbene whitening and brightening agents of Formula I above'in aqueous media containing Water-soluble synthetic organic anionic detergents. A

further object of this invention is the provision of .these benzimidazolylstilbenes in asolid composition which can be uniformly dispersed, either as a comminuted solid or in melted, liquid form, in aqueous pastes of water-soluble synthetic organic {anionic detergents to produce detergents compositions providing the full dye strength of the benzimidazolylstilbene when used in laundering.

In accordance with thepresent invention, a substantially water-insoluble benzimidazolylstilbene whitening and brightening agent of Formula I above is dissloved in an amide 'of the class consisting of higher fatty acid amides and higher fatty acid (lower alkanol)amides at a temperaturein the approximate range 140-200 C., thereby forming a composition adapted to facilitate the preparation of'detergent compositions containing a uniform dispersion of a relatively small quantity of the benzimidazolylstilbene in a relatively large quantity of an aqueous paste of'a water-soluble synthetic organic anionic detergent, that is, detergent compositions having up to about 0.5% by weight of the benzimidazolylstilbene dispersed therein. Using any suitable means of stirring or blending, an appropriate amount of a solution of the benzimidazolylstilbene in the amide obtained in this manner can be added while in hot, liquid form to the detergent-paste or, if desired, allowed to solidify by cool-.

ing and then added at anyconvenient time in re-melted,-

paste; In the detergent com-' the benzomidazolylstilbene;

whitenin g'and brightening agent is-dispersed uniformly liquid form to the detergent positions thus prepared,

and satisfactorily, as evidenced by th'e fact that the dyeing strength of the detergent compositions is approximately of the calculated amount based onthe weight of the benzimidazolylstilbene employed, as determined standard dye testing procedures.

.The higher fatty acid amides useful in the practice of this invention are'saturated aliphatic carboxylic primary amides'of the general formula R- CO--'NH where R is an alkyl radical having about 8-18" carbon atoms. These amides are ofcourse well-known andreadily available compounds, being readily derived, for example, from the conespondinghigher fatty acids obtained by the; hydrolysis of various naturalfats' and oils such as" coconut" oil and tallow. The corresponding higher fatty acid (lower -a1kanol)amides, having 8-18 carbon atoms, in the? ,aliphatic' chain, are likewise well-known and are readily prepared-byamidation of thecorresponding higher fatty; acids or a suitable functional derivative thereof with a (monoor cli-lower'alkanoDarnine such as ethanolamine,

diethanolamine, isopropanolamine, and the like. Among the-preferred higher fatty-acid amides and higher fatty aesaeas acid (lower alkanol)amides are: coconut fatty acid amides; coconut fatty acid (lower alkanol)amides such as coconut fatty acid ethanolamides and coconut fatty acid isopropanolamides; lauramide; lauric ethanolamide; lauric diethanolamide; stearamide; stearic ethanolamide; palmitic acid amide; palmitic acid ethanolamide; and the like. These amides and (lower a1kanol)amides, in addition to functioning as a solvent for the brightening agent, can also function as a foam stabilizer, but of course other foam stabilizer substances can also be present in the detergent as known in the art.

The water-soluble synthetic organic anionic detergents involved in the practice of my invention are a Well-known class of substances (for example,.see McCutcheons Syn thetic Detergents, McNair-Dorland Company, New York, 1950, pages 120-151) and include ordinary soaps (i.e., the alkaline metal salts of higher fatty acids), sulfonates, and sulfates. Examples of these detergents are alkyl aryl sulfonates, highervalkyl sulfates, sulfated and sulfonated amides and amines, sulfated and sulfonated esters and others, and higher alkyl sulfonates, for instance sodium p-dodecylbenzenesulfonate, sodium lauryl sulfate, the sodium salt of Nemethyl-N- (2-sulfoethyl) oleic amide, the sodium salt of 2-sulfoethyl oleate, and sodium myristyl' sulfonate. These detergents are of course frequently available in admixture with each other or with inorganic detergents or builders such as tetra sodium pyrophosphate, sodium tripolyphosphate, sodium metasilicate, so dium borate, and sodium perborate, or foam stabilizers such as lauric acid isopropanolamide and coconut fatty acid ethanolamides. These mixtures are also satisfactory for the present purposes.

In carrying out my invention, the amount of benzimid-. azolylstilbene Which is dissolved in the amide can be varied as desired up to the saturation concentration involved in each instance. As indicated hereinabove the concentration of the benzimidazolylstilbene required in the anionic detergent paste for the desired whitening and brightening effect isrelativel-y low, ordinarily being no more than 0.5% by weight and inmost instances falling in the range (Mil-01% by weight. Accordingly, it is feasible to use dilute solutions of the benzimidazolylstilbene in the amide. However, i have found that solutions having about 5% or more by weight of the benzirnidazolylstilbene have greater general usefulness than the more dilutesolutions, since the latter are less convenient to handle, due to increased volume, and may in some instances involve introduction of a larger quantity of amide than desired into the anionic detergent. 'Formost purposes, a concentration of 5-30 %-by weight of the benzimidazolylstilbene in the amide solution is convenient and satisfactory; using solutions of such concentration, the amount of the amide introduced into the'detergent paste is minimized and in fact. need be no greater than'the amount in which amides of this type are conventionally used in anionic detergents to improve detergencyfi 7- As already indicated, the practical operative temperature range in dissolving the benzimidazolylstilbene in the amideis about 140-200C. For-preparation of'relatively concentrated solutions, for instance 20% or'more', by, weight of.thebenzimidazolylstilbone, it is generally preferable for best results to employ a temperature in .the' upperportiou of the operative range, for instance 180- 200-:C. In the preparation ofless concentrated solu- 4 5-15 in the amide is cooled as rapidly as possible to solidify it quickly, and if necessary the resulting solid is comminuted in suitable fashion, as by grinding.

In carrying out this procedure, I generally prefer to cool the hot liquid solution of the benzimidazolylstilbene in the amide rapidly and efficiently by spraying it into a reservoir, or alternatively by pouring it onto the chilled rolls of a flaker so that thin brittle flakes of the desired solid are produced. The solid product obtained by these methods can be dispersed directly by conventional techniques into an aqueous paste of a Water-soluble synthetic organic anionic detergent to produce a detergent composition having a dyeing strength which is substantially 100% of the calculated strength based on the amount of benzimidazolylstilbene present.

If the hot liquid solution of the benzimidazolylstilbene in the amide is not cooled rapidly enough, use of .the solid form will result in a detergent composition having less than 100% of the calculated dyeing strength, but theresulting solid can be used quite satisfactorily in re-melted, liquid form for addition to the detergent paste.

My invention is illustrated by the following examples without, however, being limited thereto. In these ex 7 amples, the term partf and .parts are used to indicate part or parts by weight. V

Example 1 q A general procedure is as follows:

One part of a benzimidazolylstilbene having Formula I hereinabove is mixed with nine parts of a mixture of coconut fatty acid amides having the formula H i where R represents the higher fattyaliphatic radicals tions, any temperature in the range -200 C. is

satisfactory for optimum results. r i

A particularly advantageous aspect of my invention is that item be employed to provide'compositions con"- taining thebenzimidazolylstilbene and .thejamide" in -.a conveniently handled, comminuted solid'forrn-Which canbe readily and uniformlydispersed in aqueous pastes of water-soluble synthetic organic anionicdetergents. For such purpose, .a hot liquid solution containing up to about 20% by weight of the benzimidazolylstilbene, f preferably. f

corresponding to those in the coconut fatty acids, RCOOH, and the mixture is heated to C. After all the solid has dissolved, the resulting'solution is'stirred well while being heated at 150-160 C. and then using preheated nitrogen is sprayed into a reservoir at room temperature (about 25 C.) to cool the liquid rapidly and solidify it. The resulting solid contains 10% by' weight of the benzimidazolylstilbene.

Using the same general procedure, but melting the mixtures together in each instance at C., there are employed appropriate amounts of the benzimidazolylstilbene and the mixture of coconut oil fatty acid amides to pro-, duce dry comminuted preparations containing 20% and 33%, respectively, of'thebenzimidazolylstilbene.

Appropriate amount-s of the 10%, 20%, and-33%- .were employed in accordance with the above described produces: 4-(benzimidazol-2-yl) -4'-{1-[2-hydroxy-3-(2,3.- dihydroxypropoxy] propylbenzimidazol 2 yl}stilbene,- 4-

(benzimidazol -;2 yl) 4' (1 4 allylbenzimidazol 2-,

yl) stilbene, and the mixture of hydroxyethylated deriva tives of 4-(benzimida'zol-2-yl)-4'-{1-[2-hydroXy-3-(2,3-dihydroxypropoxy]propylbenzimidazol 2 yl}stilbene described 'in Example 28E of;U.S. Patent 2,838,504. :The water-soluble synthetic organic ,ani onic, detergents ,.em;-

ployed in preparing these compositions were: -(1) De-.-'

tergent 'Lfconsisting of 21.8% of a mixture of-sodium lauryl sulfate and .-.sodium dodecylbenzenesulfonates; 18.2% of sodium sulfate, and 60% of sodiumytriphos-n vphate; (2) Detergent H, consisting of 19.1% of sodium I dodecylbenzenesulfqnates, 15.6% of sodium sulfate, 55 of sodium triphosphate, and 10.3% of sodium zcarbona-tei' and (3) white soapconsisting of the sodium salts of "the C rcmfatty acids derived from .tallow.' In each .,:of-the detergent compositions thus obtained, .I e whitening:

Example: 2

Using the manipulative procedures described above in Example 1, two series of-detergent compositions were prepared in which equal weights, respectively, of coconut fatty acid ethanolamides-and coconut fatty acid isopropanolamides were substituted for the coconut fatty acid amides used in Example 1. In the two series of detergent compositions thus obtained, in each instance the whitening and brightening efiect of the composition was 100% of the calculated amount, based on the weight of the benzimidazolylstilbene employed.

Example 3 The procedures described in Example 1 were repeated for the preparation of the solutions of the benzirnidazolylstilbenes in the amide with the exception that the hot liquid solution was cooled by pouring it into a steel tray which rested on a polyethylene bag filled with chipped ice. The dyeing strength of the detergent compositions prepared from the solidified product by dispersing the ground solid product in the aqueous detergent paste were in each instance approximately 85% of the strength calculated on the basis of the weight of the benzimidazolylstilbene employed. On the other hand, when the ground solidproduct, instead of being added as such to the detergent paste, was re-melted by heating it to 100-110" C. and the resulting hot liquid was mixed with a hot (76 C.) aqueous detergent paste, the detergent compositions thus obtainedhad a dyeing strength which was 100% of the calculated amount. 7

In the manipulative procedures of the foregoing examples, there can be used, as the whitening and brightening agent, the following: 4-(benzimidaZol-2-yl)'-4-(lmethylbenzimidazol-Z-yl) stilbene; 4,4-bis l- (Z-hydroxyethyl) benzimidazol-Z-yl] stilbene; 4-(benzimidazol-2-yl) 4 [1 (2 hydroxy 2 sulfopropyl)benzimidaz0l-2-yl]- stilbene; 4'-[ l- (carboxymethyl)benzimidazQlQ-ylb t?(;1- methylbenzimidazol-Z-yl) stilbene; I ftAf-bis l- 2-cyanoethyl) benzimida'zol-2-yl) stilbene; 4-(benzimidazol-2-yl) -4-7 l-allylbenzimidazol-2-yl) stilbene; and 4,4'-bis l-(orthochlorobenzyl)benzimidazol 2 yl]stilbene. In each instance, the resulting detergent compositions obtained have a dyeing strength which is approximately 100% of the calculated amount based on the weight of the benzimidazolylstilbene employed.

I claim:

1. The process for obtaining a uniform dispersion of a relatively small quantity of a benzimidazolylstilbene whitening and brightening agent having the formula g wherein Y and Y are radicals of the class consisting of 4 hydrogen,-lower alkyl containing l-6 carbonatoms, hy-

droxy lower alkyl containing 2-6 carbon atoms, 2-hy- 6'5 C. in acoconutfatty acid ethanolamide; and mixing the resulting solutionwith the said aqueous paste in the pro-- portionof 0.0l.-0.5 part by weight of'thebenzimidazolylstilbene per hundred parts by weight of the aqueous paste.

droxy-3 -sulfopropyl, hydroxy-oxaalkyl containing 3-15 carbon atoms, carboxy-lower alkyl containing 2-6 carbon atoms, cyano-lower alkyl containing 3-6 carbon atoms, allyl, methallyl, and monocyclic aralkyl containing 7-11 carbon atoms, at least one of the radicals Y and Y being other than hydrogen, in a relatively large quantity of an aqueous paste of a water-soluble synthetic organic anionic detergent which comprises: dissolving the benzimidazolylstilbene at a temperature inthe range -200 C. in an amide of the class consisting of higher fatty acid amides and. higher fatty acid lower alkanol amides; and mixing the resulting solution with the said aqueous paste in'the proportion of 0;0l-0.5 part by weight of the benzimidazolylstilbene per, hundred parts by weight of the aqueouspaste. r

2. The process in accordance with claim 1 wherein Y is hydrogen and Y is, a hydroxy-oxaalkyl radical containing 3-15 carbon atoms, and the amide is a higherfatty acid amide.

3. The process in accordance with claim 1 wherein Y is hydrogen and Y is a hydroxy-oxaalkyl radical containing 3-15 carbon atoms, and the amide is a higher fatty acid lower alkanolamide,

4. The process in accordance with claim 1 wherein Y 5. The process in, accordance with claim 1 whereinY is a hydroxy-lower alkyl radical containing 2-6 carbon atoms and Y is a hydroxy oxaalkyl 'radi'cal containing 3-15 carbon atoms, and the amide is lahigher fatty lower alkanolamide.

' 6. The process for obtaining a dispersion'of a relati'vely small quantity of abenzimidazolylstilbene whitening brightening agent having the formula where Y is a hydroxy-oxaalkyl radical containing 3-15 carbon atoms, in'arelatively large quantity of an aqueous pasteof a water-soluble syntlie'ticorganic anionic sulfonate detergent which comprises: dissolvingthe benzimidazolylstilbene at a temperature in the range 140-200 v7. The process for obtaining a uniform dispersion of a relatively small 'quantity of a benzimidazolylstilbene whitening brightening agent having the formula Y aaaa aaa ture in the approximate range 140-200 C. a water-insoluble benzimidazolylstilbene whitening and brightening agent having the formula wherein'Y and Y are radicals of the class consisting of" hydrogen, lower alkyl containing 1-6 carbon atoms,thy-

droxy-lower alkyl containing 2-6 carbon atoms, ,2-hydroXy-3-sulfopropyl, hydroxy-oxaalkyl containing 3-15' carbon atoms, carboxy-lower alkyl containing 2-6' carbon atoms, cyano-lower alkyl containing 3-6 carbon atoms, allyl,]methallyl, and monocyclicf aralkyl containing 7-11 carbon atoms, at least one of the radicals Y and Y being other thanhydrogen, in an amide of the class consisting of higher fatty acid amides and higher fatty acid lower alkanolarnides.

9. A solid composition obtained by dissolving at a temperature in the approximate range 140-200 C. about 15% by weight of a benzimidazolylstilbene whitening and brightening agent having the formula wherein Y and Y are radicals of the class consisting of hydrogen, lower alkyl containing 1-6 carbon atoms, hydroxy-lower alkyl containing 2-6--carbon atoms, 2-hy-' droxy-S-sulfopropyl, hydroxy-oxaalkyl containing 3-715- carbon atoms, carboxy-lower alkyl containing2-6 carbon atoms, cyano-low er alkyl containing 3-6 carbonatoms, allyl, niethallyl, and monocyclic aralkyl containing 7-11 carbon atoms, at least one of the radicals Y and Y being other than hydrogen, in an amide of the class consisting of higher fatty acid amides and higher fatty acid lower alkanolamides, and solidifying the resulting solution by cooling it rapidly. 7 r

"10. A solid composition obtained by dissolving at a temperature in the approximate range -200 C. about 5-15% by weight of 'a benzimidazolyl'stilbene whitening and'brightening agent having the formula where Y is a hydroxy-lower alkyl radical containing 2-6 carbon atoms and Y is a hydroxy-oxaalkyl radical containing 3-15 carbon atoms, in a coconut fatty acid ethanolamide, and solidifying the resulting solution by cooling it rapidly.

References t'lited in the file, of this patent UNITED STATES PATENTS 2,607,740 Vitale etal -Aug. 19, 1952 2,733,214 Vitale et a1. "Jan. 31, 1956 2,838,504 vCrounse June 10, 1958 OTHER REFERENCES 'Reinisch et al.: Fatty Acid Alkylolamides, pages 169-178 in Jour. Soc. of Cosmetic Chemists, 01. s, No.

3, November 4.

Claims (1)

1. THE PROCESS FOR OBTAINING A UNIFORM DISPERSION OF A RELATIVELY SMALL QUANTITY OF A BENZIMIDAZOLYLSTILBENE WHITENING AND BRIGHTENING AGENT HAVING THE FORMULA