US3716532A - Process for preparing crystalline forms of 4,4'-bis[(4-anilino-6-morpholino-1,3,5-triazin-2-yl)-amino]-stilbene-2,2'-disulfonic acid - Google Patents

Abstract

Novel crystalline 4,4''-bis((4-anilino-6-morpholino-1,3,5triazin-2-yl)-amino)-stilbene-2,2'' -disulfonic acid is provided by a procedure involving treating cyanuric chloride with 4,4''diaminostilbene-2,2''-disulfonic acid, reacting the product thus obtained, without isolation, with aniline followed by reacting the resulting product, without isolation, with morpholine and precipitating the product thus obtained by treatment with an acid. The new crystalline 4,4''-bis((4-anilino-6-morpholino-1,3,5triazin-2-yl)-amino)-stilbene-2,2'' -disulfonic acid is incorporated in detergents, soaps or other laundry products and imparts to the aforesaid and similar materials, unexpected and surprising superior over-all performance properties.

Description

United States Patent Tscharner et a1.

[ 51 Feb. 13,1973

PROCESS FOR PREPARING CRYSTALLINE FORMS OF 4,4 '-BIS[(4- ANILINO-6-MORPHOLINO-l,3,5- TRIAZIN-2-YL)-AMINO]-STILBENE- 2,2'-DISULFONIC ACID Inventors: Christopher Tscharner, Neumattenweg 9, Benken-Baselland, Switzerland; Maurice Schwarz, 1 5 Appletree Lane; Richard Pichler, l l Westfield Rd., both of Warwick, RI. 02888 Filed: April 13, 1970 Appl. No.: 27,587

US. Cl. ..260/240.l, 252/110, 252/117,

252/524, 252/542, 26 /240 B Int. Cl. ..C07d 55/22 Field of Search ..260/240 B, 240.1

References Cited UNITED STATES PATENTS Wilson .r; ..260/247.1 Obayashi et a1. ..252/152 Gold et a1 ..260/240 Tscharner ..260/240 FOREIGN PATENTS OR APPLICATIONS 1,485,673 5/1967 France ..260/240 1,093,507 12/1967 Great Britain ..260/240 Primary Examiner1-Ienry R. Jiles Assistant ExaminerG. Thomas Todd Att0rneyKarl F. Jorda and Martin J. Spellman [5 7 ABSTRACT The new crystalline 4,4-bis[(4-anilino-6-morpholino- 1,3,5-triazin-2-yl)-amino]-stilbene-2,2'-disulfonic acid is incorporated in detergents, soaps or other laundry products and imparts to the aforesaid and similar materials, unexpected and surprising superior over-all performance properties.

3 Claims, 3 Drawing Figures PATENTEDFEB] 3191a SHEET 2 [IF 3 I N VEN TOR.

PROCESS FOR PREPARING CRYSTALLINE FORMS OF 4,4 '-BIS[(4-ANILINO-6-MORPHOLINO- l ,3 ,5-TRIAZIN-2-YL)-AMINO]-STILBENE-2,2 DISULFONIC ACID DESCRIPTION OF THE PRIOR ART The use of N,N-bis-triazinyl derivatives of 4,4- diaminostilbene-2,2-disulfonic acid for the brightening of cellulose and polyamide substrates has been known for a considerable period of time and has been greatly extended for use in the fluorescent whitening of textile materials. The fluorescent whitening is effected today not only by the textile producer or finisher including the manufacturers of synthetic materials but, to an increasing extent, also by the housewife who washes her laundry with detergents and/or soaps containing fluorescent whitening materials. Thus, in order to improve and/or increase the whitening effect, fluorescent whitening agents are incorporated into a washing agent during the production of such agents.

In an attempt to impart to laundry (white loads) a whiter aspect, the producers of washing agents have constantly increased the amount of fluorescent whitener incorporated in their products. However, the use of relatively large concentrations of whitener, that is about 2-10 kgs. of whiteners per ton of detergent, often causes a distinct discoloration of the washing powder and this undesirable discoloration often increases when the washing agent that is, the detergents, soaps or other laundering products are stored in a damp or humid atmosphere. The freedom from discoloration of the washing powder itself during the several stages of manufacture is used by the producer as a check and control as the production steps are proceeding as desired. However, such a manufacturing control is difficult or impossible if the mixture containing the fluorescent whitening agent actually causes discoloration of the product during its manufacture.

Canadian Pat. No. 783,566 relates to a salt of 4,4- bis(4-anilin0-6-morpholino-s-triazin-Z-ylamino)-2,2'- stilbenedisulfonic acid and more particularly, to a novel crystalline form of the disodium salt of the aforesaid acid. The aforesaid novel crystalline material is characterized by improved properties as an optical bleaching agent.

The disodium salt that is, disodium 4,4'-bis(4- anilino-6-morpholino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonate is a known compound having valuable properties as a fluorescent optical bleaching agent and which is used as a whitening and brightening agent in detergent compositions for laundering textile goods. However, the aforesaid known compound has been found to be objectionable because of its light sensitivity and this light sensitivity is objectionable especially when the product is incorporated into white detergents.

According to the procedure described in Canadian Pat. No. 783,566, disodium 4,4- bis (4-anilino-6- morpholino-s-triazin-2-ylamino )-2 ,2 '-stilbenedisulfonate is obtained in the form of cream colored needleshaped crystals and such crystals are characterized by excellent light stability. The novel procedure for preparing the aforesaid new crystalline material involves heating, at a temperature between about and 200 C, amorphous disodium 4,4'-bis (4-anilinomorpholino-s-triazin-Z-ylamino)-2,2-stilbenedisulfonate with one-half to five molecular proportions of aniline or morpholine in an aqueous medium having an initial pH of about 8 to 12 until approximately 80 to percent of the disodium 4,4'-bis(4-anilino-6-- morpholino-s-triazin-2-ylamino)-2,2-stilbenedisulfonate is in the form of crystalline needles. However, the novel crystalline material is also characterized by a series objectionable feature that is, its unsuitability for use in detergent or laundering compositions, at low temperatures.

Further, the whitening effect of practically all fluorescent whitening agents is substantially reduced at low temperatures. In addition, low temperature whitening agents yield yellow speckles in detergent on recycling the detergent through the spray tower.

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to new crystalline forms of 4,4'-bis[(4-anilino-6-morpholino-l,3,5- triazin-2-yl)-aminol-stilbene-2,g disulfonic m acid, cmmoNnossz, having the following chemical structural formula;

A He E I E www The new crystalline material possesses unusual and most surprising properties. Specifically, as indicated above, while the effectiveness of most fluorescent whitening agents is substantially reduced at low temperatures, the fluorescent whitening effect at low temperatures of the novel crystalline forms of 4,4-bis-[(4- anilino-o-morpholino-l ,3 ,5-triazin-2-yl)-amino]-stilbene-2,2'-disulfonic acid are substantially unaffected. In addition to the aforesaid unusual property of extremely high whitening effect at temperature, the novel crystalline material of the present invention is characterized by excellent bleach stability. Still further, while most fluorescent whitening agents used at low temperatures are troubled with the formation of yellow speckles, the novel crystalline material of the present invention does not yield yellow speckles. Thus, the novel crystalline forms of 4,4'-bis[(4-anilino-6- morpholino-l ,3 ,5-triazin-2-yl)-amino]-stilbene-2,2 disulfonic acid possess the rare and most unusual combination of properties namely (1) detergent powder whitener, (2) excellent fluorescent whitening effects even when used at low temperatures, (3) excellent bleach stability and (4) freedom from formation of yellow speckles.

The present invention also includes within its scope the use of the aforesaid fluorescent whitening agent in detergents, soaps and other laundry products such as bleaches, softeners, and the like.

disulfonic acid disodium salt product is recovered, by conventional procedures and suitably, by filtration. The product is then washed, acidified to a pH between about 2 and 6 and preferably between about 2 and 3. The reaction involving the acidification of the disodium salt is illustrated as follows:

The starting materials used in preparing the novel product of the present invention are produced by known methods similar to those described, for example, in U.S. Pat. No. 2,762,801 or Swiss Pat. No. 321,109. The procedure involves condensing 1 mol of disodium 4,4'diaminostilbene-2,2-disulfonate or alternatively, the free acid that is, 4,4'-diaminostilbene- 2,2'-disulfonic acid (DAS) with 2 mols of cyanuric chloride (CC) at a low temperature that is, at a temperature between about -l0 and C and preferably, between about 6 to +5C. A suitable solvent and illustratively, methylethylketone, for cyanuric chloride is used in this step. The resulting intermediate product, disodium 4,4-bis(4,6- dichloro-s-triazin -2ylamino)-2,2'-stilbenedisulfonate (CC/DAS) is then reacted with aniline (2 mol equivalent to 1 mol of DAS) at a temperature between about 5 and 50C and this step is followed by converting the remaining 2 chlorines in the 4,4'-bis-{2"-phenylamino-4"-chloro-striazinyl-(6")-amino1-stilbene-2,2'-disulfonic acid by heating the reaction mixture at a temperature between about 50 and 90C with morpholine. The above steps in the process are performed continuously that is, without isolating the intermediate products. The novel step in the process involves acidifying the reaction mixture to obtain the desired product, i.e., 4,4'-bis[(4- anilino-fi-morpholino-l ,3 ,5-triazin-2-yl )-amino 1 stilbene-2,2 '-disulfonic acid.

The new crystalline forms of 4,4'-bis[(4-anilino-6- morpholino-l ,3 ,5triazin-2-yl)-amino]-stilbene-2,2 disulfonic acid are obtained either, as indicated above, by acidifying the reaction mixture to a pH ranging between about 2 and 6 and preferably, between about 2 and 3 or alternatively, following the reaction with morpholine, the resulting 4,4-bis[(4-anilino-6- morpholino-l ,3 ,5 -triazin-2-yl)-amino1-stilbene-2,2

On acidification, the desired product precipitates our of solution and said product is then recovered by conventional means such as, for example, by filtration. On drying, the desired product is obtained in the form of a crystalline material.

The novel crystaliine products of the present invention provide outstanding superior performance characteristics as compared with known fluorescent whitening agents since, the present compound provides the rare combination of unusually excellent detergent whitening ability coupled with excellent low temperature performance. ln addition to this unusual combination, the present novel crystalline material does not form yellow speckels in detergents on recycling the latter through the spray tower and further, the products of the present invention are also characterized by excellent bleach stability.

Still further, the crystalline material of the present invention is capable of going into solution at an extremely rapid rate and therefore can be drawn on to fibers at low temperatures that is, at temperatures between about 35 and 60 C. Since the present product is available to exhaust on to the fabric even at low temperatures, its effectiveness at cold water washing is essentially equivalent to that of warm water washing. Consequently, the present product is ideally suitable for use in household laundering.

Solid detergents, including soaps and the like laundering compositions, to which the fluorescent whitening agents, according to the present invention, can be added at any step of their production include anionic detergents such as alkali metal salts of alkyl-aryl sulfonates especially alkyl-benzene and alkyl-naphthalene sulfonates, alkali metal salts of sulfates of higher fatty alcohol or alkali metal salts of higher fatty acids, in which the cation portion consists preponderantly of sodium ions. The following is a typical anionic detergent formulation:

16% sodium dodecylbenzene sulfonate 35% sodium tripolyphosphate 5% tetrasodium pyrophosphate 6% sodium silicate 5% water 0.5% carboxymethylcellulose Balance to 100 percent sodium sulfate (exclusive of additives) The present fluorescent whitener agent can also be included in nonionic detergent formulations and a typical formulation of this type is as follows:

8% nonylphenol polyethyleneglycolether 35% sodium tripolyphosphate 5% tetrasodium pyrophosphate 6% sodium silicate 8% water 0.5% carboxymethylcellulose Balance to 100% sodium sulfate (exclusive of additives) The amount of fluorescent whitener agent added is usually at least about 0.1 percent up to about 1.0 by weight of the detergent, soap, softener, or like material.

The invention is illustrated in greater detail by the following examples which are not considered to be limiting in any way. Unless otherwise stated, parts are given as parts by weight and the temperatures are in degrees Centigrade.

EXAMPLE 1 Preparation of 4,4-bis[ (4-anilino-6-morpholino-l,3,5- triazin-2-yl)-amino]-stilbene-2,2-disulfonic acid 100 parts of 4,4'-bis[4-anilino-6-morpholino-l,3,5- triazin-2-yl)-amino]-stilbene-2,2'-disulfonic acid disodium salt and 4,000 parts of water are heated, accompanied by agitation, at 80C. 260 parts of 1.8 normal solution of hydrochloric acid in water is added in a stream to achieve a pH of 2.5. The mixture is then tiltered, while hot, and the precipitate is washed with 2,000 parts of hot water. The wet material is then dried at 100C, in vacuum, to obtain the desired product, in crystalline form.

The crystalline product of this example is characterized by an X-ray diffraction diagram having the following characteristic lines expressed in 2 9:

Fairly strong lines at 5.3, 8.9, 11.4, 15.5, 19.8, 21.2

and 25.8

The X-ray pattern for this crystalline material is shown in accompanying FIG. 1.

EXAMPLE I1 400 parts of water are heated, accompanied by agitation, at a temperature of 80C. To this solution is added a solution of parts of 4,4-bis-[(4-anilino-6- morpholino-1,3 ,5-triazin-2-yl)-amino]-stilbene-2,2'- disulfonic acid disodium salt dissolved in 400 parts of water; Concurrently, a 1.0 normal solution of hydrochloric acid in water is added at such a rate that the pH of the resultant solution is maintained at 6. After the addition of the brightener solution,the temperature is kept at 80C and the pH is maintained at 6 for an additional hour. The reaction mixture is then cooled to room temperature and filtered. The precipitate is washed with cold water to remove the salt and then dried at 100C in vacuum to obtain the desired crystalline product.

The crystalline product is characterized by an X-ray diffraction diagram having the following characteristic lines expressed in 2 0:

A strong line at 9.3; a fairly strong line at 10.1; a strong line at 16.3; fairly strong lines at 18.8, 19.3, 20.0, 23.3 and 24.6; a strong line at 25.5 and a fairly strong line at 28.1.

The X-ray pattern of this crystalline material is shown in accompanying FIG. 3.

EXAMPLE Ill The procedure set out in Example 11 is followed except for the fact that the pH was'maintained at 2 rather than at 6.

The crystalline product is characterized by an X-ray diffraction diagram having the following characteristic lines expressed in 2 0:

Fairly strong lines at 3.4 and 5.1; a strong line at 8.9 and fairly strong lines at 9.7, 10.6, 15.9, 16.6, 18.5, 20.4, 21.5, 22.6 and 25.4.

The X-ray pattern of this crystalline material is shown in accompanying FIG. 2.

EXAMPLE IV 700 Parts by weight of cyanuric chloride are added to 6,000 parts by weight of methylethylketone and 6,000 parts by weight of icewater. A solution of 785 parts by weight of the sodium salt of 4,4'-diaminostilbene-2,2-disulfonic acid and 200 parts by weight of sodium carbonate in 6,000 parts by weight of water is poured, within 1 hour, accompanied by stirring, at a temperature of 0.5C into the cyanuric chloride suspension thus obtained. 353 parts by weight of aniline are added all at once and then the pH is held at 6-8 by the addition of 155 parts by weight of sodium hydroxide dissolved in 155 parts by weight of water. The yellowish suspension is then stirred and heated to 50C until all the aniline has disappeared. 665 Parts by weight of morpholine are added and the reaction is heated, accompanied by agitation, to distill the methethylketone at a temperature of about 100C. The reaction mixture is allowed to cool to -90C and held at this temperature while 300 parts by weight of sulfuric acid (98 percent) are added, to a pH of 2-3 accompanied by agitation, within the one hour. The yellow slurry is cooled and the solid material is recovered by filtration. The wet product is dried at 100C in vacuum to obtain the desired product, 4,4'-bis[(4- anilino-6-morpholino-l ,3 ,5-triazin-2-yl )-amino ]-stilbene-2,2'-disulfonic acid.

The crystalline product is characterized by an X-ray diffraction diagram identical with the product of Example 1 supra.

The detergent whitening characteristics of this product were examined. The procedure used involved incorporating measured concentrations of the aforesaid whitener product into a typical anionic heavy duty detergent illustrated above by slurrying the detergent and whitener with about 1N NaOH until a smooth, homogeneous paste is obtained. The paste is dried in a gravity convection oven at C and the resulting dried detergent cake is ground through a 20 mesh screen. The powder is sieved through a 60 mesh screen and the fines are discarded. The detergent powder is then allowed to stand overnight at about 85 percent relative humidity before color measurement. The hue of the powder is measured on a Hunter Color Difference Meter, Model D-25, using L", a, and b units. A whiteness" value is calculated according to the equation W=L+3a-3b (see Stensby, P.S., Soap and Chemical Specialties, April, May, July, August, September, 1967) the higher the value, the greater the whiteness of the powder. Only whitener values above 75 can be considered measurement of white.

All wash tests are carried out in a Terg-OTometer (150 rpm) for 10 minutes using 600 ml water, 20 g cotton fabric, and l g detergent (containing 0.4 percent full strength whitener) predissolved for 30 seconds prior to addition of fabrics or bleach. In tests with bleach, the wash liquor is exposed to 200 ppm NaOCl prior to addition of the fabrics. The washed fabrics are rinsed under running tap water and drip-dried in the dark. Fabric fluorescence is measured using a Lumetron Colorimeter equipped with a mercury lamp and reflectance attachment, and fabric color is measured using the Hunter Color Difference Meter.

The performance characteristics of the product of Example 1V above were compared with a low temperature whitener material which is presently marketed.

*A commercially available whitener, 4,4'-bis[4-ani1ino-6[bis(2- hydroxyethyD-amino1-l,3,5-triazin-2-yl]-amino-stilbene-2,2 '-disulfonic acid.

SPECKLING As compared with other low temperature whiteners some of which are presently being sold, the crystalline material of Example 1V does not cause yellow speckling of detergent upon recycle of the detergent in spray drying operations.

Further, as indicated above, the novel crystalline material of the present invention is superior to the dis- 8 odium 4,4'-bis(4-anilino-6-morpholino-s-triazin-2- ylamino)-2,2-stilbenedisulfonate disclosed in Canadian Pat. No. 783,566 in that the last mentioned compound is unsuitable for use as a whitening agent in detergent or laundering compositions at low temperatures. The comparison data set out above clearly indicates the superiority of the crystalline material of the present invention both in detergent whitening, high and low temperature performance as well as bleach stability.

The X-ray patterns of the crystalline material referred to above were obtained by the well known pAowder technique described for instance, by Krug and lexander m -ray Diffraction Procedures for Polycrystalline and Amorphous Materials," published by John Wiley and Sons, New York, N.Y. (1954), especially on pages 235 et seq., using a Proportional- Counter equipped Goniometer made by N.V. Philips Gloeilampen Fabrieken, Eindhoven, Netherlands. The instrument does actually record the intensity of the diffracted ray along the vertical axis in relation to the diffraction angle 26 using CuK radiation. The interplanar spacings d are subsequently calculated in Angstrom units from the diffraction angles by using the Bragg equation n. )t =2d. sin 0. The values given are accurate within 2 percent and in most cases, particularly with d values of less than 10 A, variation is less than 1 percent. Therefore, this variation should be taken into account when interpreting the specification and appendant claims.

What is claimed is:

1. In a process for the preparation of a crystalline form of 4,4-bis[(4-anilino-6-morpholinol ,3,5-triazin- 2-yl)-amino]-stilbene-2,2-disulfonic acid by a procedure involving reacting cyanuric chloride with 4,4'-diaminostilbene-2,2'-disulfonic acid or an alkali metal salt thereof, contacting the CCIDAS product with aniline followed by contacting the product thus formed with morpholine, the improvement comprising acidifying the resulting 4,4'-bis[(4-anilino-6- morpholinol ,3,5-triazin-2-yl)-amino]-stilbene-2,2 disulfonic acid disodium salt, with a strong mineral acid at temperatures of from about 70-90C to a pH between 2 and 3 and purifying said acidulated product while at elevated temperatures.

2. The process in accordance with claim 1 including the steps of conducting the acidulation of said disodium salt at a pH of about 6 and thereafter cooling said acidulation mix to ambient temperatures and thereafter purifying said disulfonic acid product.

3. The process in accordance with claim 2 including the step of acidulating said salt at a pH of about 2.

t I I I It

Claims (2)

1. In a process for the preparation of a crystalline form of 4, 4''-bis((4-anilino-6-morpholino-1,3,5-triazin-2-yl)-amino)-stilbene-2,2'' -disulfonic acid by a procedure involving reacting cyanurIc chloride with 4,4''-diaminostilbene-2,2''-disulfonic acid or an alkali metal salt thereof, contacting the CC/DAS product with aniline followed by contacting the product thus formed with morpholine, the improvement comprising acidifying the resulting 4,4''-bis((4-anilino-6-morpholino-1,3,5-triazin-2-yl)-amino)-stilbene-2,2'' -disulfonic acid disodium salt, with a strong mineral acid at temperatures of from about 70*-90*C to a pH between 2 and 3 and purifying said acidulated product while at elevated temperatures.

2. The process in accordance with claim 1 including the steps of conducting the acidulation of said disodium salt at a pH of about 6 and thereafter cooling said acidulation mix to ambient temperatures and thereafter purifying said disulfonic acid product.

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