US2993892A - Stilbene monotriazole brightening agents - Google Patents

Description

United States Patent ()fiice Patented, July 25, 1961 This invention relates to novel silbenenaphthotn'azole compounds possessing new and useful properties which render them particularly useful as fluorescing optical bleaching or whitening agents.

It is well known that textiles tend to develop a yellowish shade on aging which cannot be removed by ordinary methods of bleaching or washing. The heretofore used methods of hitting white materials with flue pigments or fugitive blue dyestulfs have become quite obsolete in modern laundry practice and have been largely superseded by methods employing fluorescent optical bleaching agents or brighteners as additives to the soap or detergent in the washing bath. These brightening agents are usually conveniently supplied commercially in the form of intimate admixtures with the soap or detergent in bars, flakes, powders, etc. The fluorescent optical bleaching agents perform their desired function by virtue of their characteristic absonption of ultra-radiations and subsequent conversion of this energy to light energy within the visible spectrum. This converted and emitted light energy tends to neutralize any yellowness of the material and thereby increase the apparent whiteness thereof.

Compounds which have been suggested and employed as fluorescent brightening agents include the following:

(I) Acylated derivatives of 4,4'-diaminostilbene-2,2'- disulfonic acid.

(II) Acylated derivatives of 4,4'-diamino-diphenyl-2,2'- disulfonic acid.

(III) Triazyl derivatives of diamino stilbene disulfonic acid.

(IV) Triazyl derivatives of diamino diphenyl disulfonic acid.

(V) Acylated derivatives of diamino dibenzothiophene dioxide, etc.

Compounds of the Types I and II are disclosed in U.S. Patents 2,518,059 and 2,643,198 and in British Patent 584,484.

Compounds of the Types III and IV are disclosed in U.S. Patent 2,618,636 and in application Serial No. 381,- 856 published May 11, 1954 by the A.P.C.

Compounds of Type V are exemplified in U.S. Patents 2,563,493 and 2,563,795.

In addition to the five types mentioned above, other triazyl compounds have been suggested. Thus U.S. Patent 2,713,054 discloses monotriazoles of the type CHsO 2 U.S. Patent 2,713,055 discloses monotriazoles of the type F 1 H2C I -i NaOaS L N/ J N: SOQNB 8H U.S. Patent 2,713,056 discloses monotriazoles of the type N YC2/ 6 N N H N 1 wherein X designates oxygen, sulfa, or imino, and Y alkyl or aryl.

U.S. Patent 2,713,057 discloses monotriazoles contain ing a silbene moiety of the type formulated in claim 2:

CHaO

None of the aforementioned patents relates to stilbene monotriazoles containing a naphtho substituent. Such compounds, however, are disclosed in Patent 2,784,183, and representative of the compounds in the latter patent is the following compound:

N S 03H The compounds of the present invention are naphtho monotriazole stilbenes containing a single sulfo substitneat and characterized by one of the following two formulas:

Q QF

and (A) The novel compounds of this invention are characterized by having excellent fiber substantivity, an aesthetically more desirable hue as contrasted with an aesthetically undesirable yellow hue of some of the prior art brightening agents, a greater apparent whiteness than prior art compounds, outstanding resistance to bleaching agents commonly used in laundering processes, an excellent lightfastness. As a result of these remarkable properties fabric washed with soaps or other detergents containing small amounts of the novel compounds of this invention usually in the form of the sodium or other alkali metal salt become much brighter in the case of colors and whiter for others than fabrics which are washed either in the absence of such brightening agents or in the presence of the previously known brightening agents.

The compounds of this invention may also be incorporated in synthetic fibers and fabrics particularly during the manufacture thereof and especially in those of cellulose, cellulose acetate and the like, by adding a small amount of the brightening agent to the spinning solutions or precipitating baths in order to achieve a noticeable increase in the whiteness of the finished product. These brighteners may also be used to effect a whitening of paper by the impregnation thereof (with the selected brightening agent) or by the inconporation of the brightening agent in the paper making pulp prior to the final drying thereof. Additionally, the brightening agents of this invention may be employed to effect a whitening of waxes, gums and the like by a ding small amounts of the agent to such substances.

The two compounds of this invention, as will be noted from the above formulas, have only a single sulfo substituent in the entire molecule. In Formula A this sulfo substituent is present in the stilbene moiety meta with respect to the ethylene bridge, and in the case of Formula B the sulfo is present in the -position of the naphtho ring. In compound B it will further be noted that the stilbene moiety is devoid of any substituents. It is completely unexpected that either one ofthese two compounds would be outstanding brighteners in the light of prior art statements and knowledge to the effect that in structures of the type herein contemplated, the stilbyl radical should contain a substituent in one of the ortho or para positions, and that compounds of this type unsubstituted in the stilbyl radical are of no technical use as brightening agents. Notwithstanding this teaching and knowledge in the prior art, applicants have discovered that the two compounds of this invention are not only outstanding and superior brightening agents, and in particular on cotton and nylon but that they are actually far superior in fluorescence and in lack of self color than the compounds which have heretofore been considered outstanding in the prior art.

It is therefore an object of the present invention to provide new and useful compounds having outstanding utility as brightening agents...

It is another object of this invention to provide new and useful naphtho monotriazole stilbene compounds which are outstanding brightening agents.

It is another object of this invention to provide new and useful compounds which are outstanding, optical bleaching or whitening agents, and which are characterized as naphtho monotriazole stilbenes.

It is still another object of this invention to provide methods for effecting the brightening or whitening of organic materials and in particular, textile materials.

It is a still further objectof this invention to provide improved brightening organic materials and in particular, textile materials.

It is a still further object of this invention to provide an improved brightening organic material, and in particular, textile materials, by incorporating therewith new and novel naphtho monotriazole stilbene compounds of the type hereinafter to he described.

The compounds of this invention are prepared in the general manner of the prior art by coupling a diazotized stilbene to the selected naphtylamine and thereafter oxidizing the resultant azo amino compound to the corresponding triazole form. The oxidation to the latter form results in the conversion of an ortho positioned, primary amino group (ortho to the azo linkage) to the hetero atoms of the triazolyl ring. The procedure for this oxidation may vary depending upon the choice of the oxidizing agent. For example, when one uses ammoniacal (or other organic base, e.g., pyridine, etc.) copper sulfate as the oxidizing agent, the resultant byproducts of such reagent may be removed by adjustment of the pH of the solution, i.e., the reduction products of the oxidizing agents may be solubilized by making the solution more acidic, so that the by-products are removed in the filtrate by a filtration step. Alternatively, the by-products may be removed in the filtrate by making the reaction medium alkaline with ammonia (pH 11) prior to filtration. While it is preferred to use metallic (icous) oxidizing agents such as copper sulfate, ferric chloride, ferric NH SO etc., one may also employ hydrogen peroxide, KMnO K Cr O CaOCl, Na perborate, oxygen, etc.

The following examples will serve to illustate the present invention without being deemed limitative thereof.

EXAMPLE 1 (A) Preparation of Into a 500 ml. flask fitted with stirrer, thermometer and condenser is charged 24.1 gms. (0.125 mole) of the sodium salt of 4-sulfamyltoluene and 75 mls. triethanolamine. The material is stirred to a smooth slurry, after which 26.5 gms. (0.25 mole) benzaldehyde and 34.3 gms. (0.25 mole) 4 nitrotoluene are added. The mixture is heated to C. and stirred 40 hours at this temperature. After this period 200 mls. of glacial acetic acid is added, the material is cooled to 20 C. and stirred until no further precipitation occurs. The light yellow precipitate is filtered and the presscake is carefully washed with 50 mls. glacial acetic acid. The filter cake is reslurried in 350 mls. water, and 10' mls. of 40% sodium hydroxide is added to raise the pH to about 12.5. The slurry is refiltered, washed with 2.50 mls. water and finally with 50 mls. glacial acetic acid. The product is air dried at 80 C. to give 4-nitrostil bene.

(B) Reduction of 4-nitr0stilbene to 4-amin0stilbene Into'a l-liter beaker fitted with stirrer and thermometer and heated with a gas burner is charged 200 mls. water, 35 gms. iron borings, and 4 mls. of concentrated hydrochloric acid. The slurry is heated to 95 C. and stirred 10 minutes at 95 C. At 95l00 C. over a period of hour there is added a preheated C.) solution of 21 gms. of the above 4-nitrostilbene in 100 mls. of'dimethyl formamide. The charge is then stirred for 1 hour at 95 C. 9.0 gms. of sodium carbonate is then added, increasing the pH to 10. The slurry is filtered at 90 C. through a Celite bed. The iron cake is washed with 300 mls. of dimethyl formamide heated to 95 C. The filtrate and washings are combined and diluted to 3 liters volume with Water. The precipitate is filtered, reslurried with 500 mls. water and 50 mls. of concentrated hydrochloric acid, to yield a mass of pH'=l. The material is evaporated to dryness giving 4-amin0stilbene hydrochloride.

(C) Diazotization of 4-aminostilbene hydrochloride and coupling to Z-naphthylamine-S-sulfonic acid A mixture of 5.04 grnb. (.018 mole) of 4-aminostilbene hydrochloride, 100 mls. of glacial acetic acid, and 25 mls. of water is heated to effect solution, followed by addition of 9.0 mls. of concentrated hydrochloric acid. The slurry is stirred and cooled to 8 C. At 812 C. 15.5 mls. of 10% sodium nitrate is added. The diazo is stirred /2 hour at 10 C. 4.5 mls. of 10% sulfarnic acid is added to destroy excess nitrous acid. 5.4 gms. (.024 mole) of 2-naphthylamine-S-sulfonic acid is dissolved by heating at 90 C. in 75 mls. water and 10 mls. of 30% sodium carbonate. This solution is added to the diazonium solution. After stirring /2 hour, a dropwise addition of 75 mls. of 20% sodium acetate is made over a period of 1 hour. The slurry is stirred for 18 hours, after which time tests for diazo and diazoamino are negative. The slurry is filtered and washed with water to give the product:

(D) Oxidation of the above product to the brightener N SOaNa A mixture of 29.5 gms. of the above dye cake, 120 mls. of picoline, and 25 mls. of water is added to a 500 ml. flask equipped with stirrer, theremometer, reflux condtnser andheating mantle. The material is heated to 95 C. giving a complete solution. A 90 C. solution of 13 gms. of-copper sulfate +5H O in 30 mls. water is added. The charge is stirred /z hour at reflux, after which 24 mls. of 25% sodium sulfide +2.5H O is added to neutralize the copper salts. The slurry is filtered through a Celite bed at 90 C. The copper sulfide cake is washed carefully on the funnel with 100 mls. of picoline preheated to 90 C. The Wash and mother liquors are combined in a 1 liter flask equipped for steam distillation and 10 mls. of 20% sodium carbonate solution is added. The charge is distilled with steam, removing the picoline. The brightener precipitates upon cooling to 70 C. and is filtered and washed with water. The presscakeis air dried to give the brightener:

N S03Na 6 EXAMPLE 2 Application of the above brightener to cotton H H O O some in 1 liter of water by heating to C. A 50 ml. aliquot of this material is then diluted to 250 mls., giving solution (A). The cotton cloth is agitated in the launderometer jar for 30 minutes at F. After this time the cloth is removed, rinsed, and dried. Using a fluorescent photometer a brightness reading of 75 is obtained on the dyed cloth.

EXAMPLE 3 A similar 5 gm. swatch of Indianhead cotton is dyed in similar manner with equal weight of a brightener of the formula and gives a brightness of 70.

EXAMPLE 4 The two brighteners of Examples 2 and 3 are applied to 5 gm. swatches of nylon in the same fashion. A brightness reading of 22 is obtained on nylon for the brightener of formula:

N SOsNa and a brightness reading of 20 was obtained from the the brightener (A) Preparation of SONa A mixture of 34.3 gms. (0.25 mole) of 4-nitrotoluenc, 50 mls. of carbowax 400 (polyethyleneoxide) is heated to 80C. There is added 19.3 gms. (0.10 mole)'of the sodium salt of 4-sulfamyltoluene (prepared by treating 1 mole of 4-sulfamyl-toluene with 1 mole ofsodium hydroxide in water and evaporating to dryness). Over a period of 19 hours 26 gms. of 3-forrnylbenzene sulfonic acid, sodium salt (100%) is added, adding, 1.3 gms. of the latter every hour. The charge is then diluted with 1 liter of water and 25 mls. of 40% sodium hydroxide. The slurry is heated to the boil and the water insoluble material is filtered oil. The press cake is washed with 250 mls. of hot water. The water layer is extracted with 1 liter of toluene, removing excess 4 nitrotoluene. To the water layer is added 125 gms. sodium chloride. It is cooled to 5 C., filtered and washed with 50 mls. of 20% saltsolution to give SOSNa (B) Reduction of SOrNa to the amine A slurry of 120 gms. of iron borings in 800 mls. of hot water is etched with 12 mls. of concentrated hydrochloric acid by heating minutes at 95 C. Maintaining constant volume and keeping temperature at 95 -100 C. there is gradually added 56 gms. (0.174 mole) SO Na After all is added, the slurry is stirredfor 1 hourat 95 -100 C. The material is made alkaline to phenolphthalein by adding 10 gms. of sodium carbonate. It is filtered at 95 C. through a Celite bed and the iron cake is wased with 1 liter of boiling water. The filtrate is treated with 95 mls. of 50% sulfuric acid. The precipitated material is cooled to 15% C., filtered and washed with 250 mls. water to give on air drying the compound (C) Diazotization of SOQH and coupling to Z-naphthylamine 8.0 gms. (0.028 mole) of by addition of 1.0 ml. of 10% sulfamic acid. There is then added a solution of 4.6 gms. (0.0318 mole) of Z naphthyIamine in 15 mls. of glacial acetic acid. After 2 hours additions of 150 mls. of glacial acetic acid and 7.0 gms. of sodium acetate are made to the slurry. The dye is stirred overnight to complete the coupling. The material is cooled to 10 C., filtered and washed with 50 mls. water to give a presscake of the dye (D) Oxidation of the above dye to the brightener:

SOaNa N Into a 500 ml. flask fitted with a stirrer, thermometer, reflux condenser and heating mantle are charged the above dye presscake and 200 mls. picoline. The material is heated to C. and there is added a solution of 20 gms. of copper sulfate +5H O in 50 mls. water. The material is stirred at rcflux'for 20 minutes, then the copper sulfate is precipitated with 50 mls. of 20% sodium sulfide +2.5H O. The material is filtered hot through Super Cel and Washed with 250 mls. of hot picoline. The filtrate and wash liquor are combined and steam distilled. The product is cooled to 16 C., filtered and washed with 75 mls. cold Water. The presscake is vacuum dried at C. to give the brightener:

EXAMPLE 6 Application to cotton and nylon of the following brightener:

S O 3N8 N gives brightness readings about 25% lower than those obtained with the brightener used in Example 6.

Application to cotton at 2% concentration of the weight of the fabric, of a prior art brightener of the formula:

gives an undesirable yellow hue, whereas our brightener of the formula:

S OaNa remains white on the cotton applied at this concentration. This ditference is due to the fundamentally greater self color of the brightener of the prior art which can be determined most accurately by an examination of the ultra-violet absorption curves of the two materials:

Thus a comparison of the absorption curves shows that there is over twice as much self color in the prior art compound as in the compound of this invention of Formula II. Thus K=2.2 at 400 mg for (I), whereas K=0.5 at 400 m for (H).

EXAMPLE 7 The monotriazoles of this invention (that is, of Example 1 and Example 5) are further tested for chlorine stability in the following manner. 100 parts of a Water solution containing 0.00032 part of the brightener, 25 parts Clorox solution (15 parts Clorox containing 0.052 g. active chlorine per ml. in 1000 parts of water), and 0.4 part Supersu are heated to 130 C. After 5 minutes, suificient sodium-m-bisulfite solution (2.5 g. sodium-m-bisulfite per liter of solution) is added to destroy the Clorox and 5 parts of cotton fabric added. The solution with the fabric is then placed in a launderometer for 20 minutes at 130 F. The cotton swatch, after rinsing twice in warm tap water and air drying at 55 C., is then measured for brightness with a fluorescent photometer. Employing the compound of Example 1, the reading is 80. The compound of Example 5 gives a reading of 92.

10 EXAMPLE 8 wherein one X is hydrogen and the other is M, wherein M is selected from the group consisting of hydrogen and alkali metals.

2. The compound of the formula:

S OaNa 3. The compound of the formula:

References Cited in the file of this patent UNITED STATES PATENTS 2,784,183 Keller et al. Mar. 5, 1957 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, 2393,5592 July 25 1961 Albert F. Strobel et a1.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Ratent, should read as "corrected below.

Column l line 11 for silbenenaphthotriazole" read stilbenenaphthotriazole line 41 for the patent number "2 5l8 O59 read 2,58%059 --3 column 7 q line 49 for "15% Cu" read 15 C.

Signed and sealed this 26th day of December 1961.

( SEAL) Attest:

ERNEST W. sWIDEE DAVID L. LADD Attesting Officer Commissioner of Patent ATENT OFFICE ERECTION July 25 1961 UNITED STATES P CERTIFICATE OF CO Patent No 2993 892 Strobel et alo fied that error appears in the above rreotion and that the said Letters Batent. shoul Albert F.

numbered pao d read as It is hereby oerti ent requiring oo corrected below.

" read ent number for thotriazole for the pat,

line 4 q "silbenenaph line 47 column line 11 for hthooriazole d 2 58l O59 ----'g,

Column 1. stilbenenap 2 5l8 O59 rea "15% (1.," rea Signed and sealed this 26 (SEAL) Atteet:

' DAVID L. LADD ERNEST W. SWIDER I Commissioner of Patent Attesting Officer U SCOM M-D

Claims (1)

1. THE COMPOUND OF THE FORMULA: