[1]Patented Sept. 16, 1947 2 1 4 2 7 , 5 3 7 UNITED STATES PATENT OFFICE 2,4Z7,537 DISAZO DYES FROM TETRAZOTIZED DIHYDROXY BENZIDINES Fritz Straub, Kaiseraugst, and Jakob Brassel and Peter Pieth, Basel, Switzerland, assignors to Society of Chemical ]Industry in Basle, Basel, Switzerland, a Swiss firm No Drawing. Application August IL6, 1913, Serial No. 498,883. In Switzerland February 18, 1941 11 Claims. (Cl. 260-182) 2 This application is a continuation-in-part of our copending application Serial No. 431,172, filed February 16, 1942. The present invention is concerned with valuable new disazo dyestuffs, and a process for pre- r, paring the same. The present invention- is particularly concerned with direct dyeing cotton dyestuffs (also called substantive dyestuffs), and still more particularly with dyestuffs capable of being metallized, for instance coppered, in sub- 10 stance, in the dyebath or on the fiber, as the case may be. According to the present invention tetrazotized 3:3'-dihydroxy-4:4'-dianiinodiphenyl is coupled with two molecular proportions of coupling com- 15 ponents as defined hereinafter. 3:3'-dihydroxy-4:4'-diaminodiphenyl, wwch is a known compound and which may be obtained for instance by saponifying dianisidine by means of aluminum chloride, has not hitherto found 20 any industrial use. Although a few dyestuffs prepared with tetrazotized 3:31-dihydroxy-benzidine have been described in the literature, the said compound has generally been regarded to be of no practicai value. This is probably due to 25 several facts. First of all it was generally believed that the said product would be too exPensive for the commercial manufacture of dyestuffs. Flurthermore, the very few dyestuffs hitherto prepared with the said tetrazo compound did 30 not show properties which might make them compete successfully with other dyestuffs, and it is to be remarked that, according to the prescriptions found in the literature, correct coupling is in most cases not brought about, which obviously 35 does not lead to correct disazo dyestuffs. According to the present invention it has been found that the cost of 3:3'-dihydroxy-4:4'-diaminodiphenyl is by no means prohibitive for the manufacture of dyestuffs therefrom, since 40 such dyestuffs as hereinafter defined show very valuable properties which more than outweigh any difficulties encountered in preparing the said starting material. Further, it will be shown hereinafter that correct coupling to form correct 45 disazo dyestuffs can be brought about, and that dyestuffs of much superior properties can be produced thereby. For the sake of simplicity coupling may be carried out with two molecular proportions of 50 the same coupling component. However, it is not unduiy difficult to effect coupling with two different coupling components since tetrazotized 3:3'-dihydroxy-4:41- diaminodiphenyl has a great tendency to couple first with one diazo group and afterwards with the other. 3:3'-dihydroxy-4:4'-dianiinodiphenyl may be obtained bysaponification of dianisidine by means of aluminum chloride and may be purified if necessary according to known methods@ It may be tetrazotized in known manner and the tetrazo compound may be used inimediately after tetrazotizing or may be separated, as described in the examples below. According to the present invention a tetrazotised 3 :3'-dihydroxy-4:4'-diaminodiphenyl is united with 2 molecular proportions of the same or different coupling components of which at leas@ one is a hydroxynaphthalene free from sulfonic acid groups. Such hydroxynaphthalenes are used according to this feature of the invention which contain neither a sulfonic acid group as nuclear substituent nor in external hnkage. It is advantageous that these hydroxynaphthalenes should be completely free from any substituents which have a strong solubilizing action such as carboxylic acid groups. They. may advantageously contain at least one further substituent, preferably only one further substituent of - another kind, for example an auxo-chromic group, such as a hydroxyl group, an amino (including substituted amino) group, an alkoxy group or a sulphamido group, iknd these substituents may, for example, be distributed on the two benzene rings forniing the naphthalene nucleus. It will be advantageous to use such hydroxynaphthalenes which permit a coupling in the ortho-position to the hydroxyl group. Such components are, for example, the various dihyd roxynaphthalenes, such as -1:5-, 2:6and -2:7-dihydroxynaphthalene, 2-amino-7-hydroxynaphthalene, I-amino-7- hydroxynaphthalene, 2,6-dihydroxynaphthalene - monoglycerine ether, as well as Nsubstituted amino-hydroxynaphthalenes, in which the amino group, for example, can be substituted by alkyl or hydroxyalkyl radicals. Furthermore such hydroxynaphthalenes also come into consideration which con-
[2]3 tain other substituents besides those mentioned above, e. g., a sulfonamide group. Particularly valuable dyestuffs are obtained if hyd roxynaphthalenes are used which are absolutely free from water solubilizing groups and, for example, are also free from carboxyl groups. These dyestuffs can be advantageously dyed from baths rendered alkaline with alkali hydroxide. According to another feature of the present invention atetrazotized 3:3'-dihydroxy4:41-diaminodiphenyl is coupled with twb molecular Proportions of coupling components at least one of which is a 1-hydroxynaphthalene containing an auxochromic group in the 8-position. Such auxochromic groups are, for instancei an amino or a substituted amino group, or a further hydroxyl group, or any other group possessing allX07 chrome properties. These coupling components may carry further substituents iii suitable positions of the naphthalene nucleus, for instance nonsolubilizing substituents, such as halogen. In all the instances mentioned above coupling is effected iii an alkaline medium. It i@ tb be r@marked, however, that there are many couplihg components, especially those of the naphthalene series, which do not combine in a satisfactory manner with tetrazotized 3:31-dihy(iroxy-4:41diaminodiphenyl when coupling occurs in the usual manner, i. e., in a medium al'kaline with sodium carbonate, even. if pyridine or similar Promoters are added. The combination is often inconiP,Iete to such an extent that only little or no disa.zo dyestuff is produced, and a monoazo dyestuff is obtained as main product. It is a furtlier feature of the present invention that in ali 'instances where c6mbination is slow and/ok incomplete with the u@@al boui)liiig iiiethods, coiii3ling is effected in a riiediui-A itlkaliiie with a hydio)iide of the alkali 6r alkalihe darth metal series including ariim6iiia. It is oftefi desitabl[. to usb S'trongly c6,ustic alkalihe irfedia, for instance @trong solutions -of 6austic potash br sodet but, in other insta-nees, the hydronides of calciu M, barium, strontiumor magnesium are suitable too, whereas media substantially free from carbonate generally appear to be desirable wheiiever COMbination is diffi6ult. If the@e reactioii media @re pr6perly iised @o'Mbiri@Ltion inay also be bffected with 2-hydroxynaphthalene sulfohic acids, such as 2-hydrox-ynapht I halene-6-siilfonic acid, 2-hydroxynaphthalene-3:6-disulfonic acid, as w6ll as with 2amino -- 5 -- hydroxynaphthAleiie-7-sulfonic acid and 2-amino-5-hydroxynaphthalene-1:7-disul fonic acid, substantially avoiding the producticl@- of monoazo-dyestuffs. The disazo dyestuffs of the present invention are suitable for dyeing and printing,the inost diverse, materials, especially cellulose fibers, such as cotton and other vegetable fibers, rayon from regeiiera-ted cellulose includihg staple hbers, and als6 for dyeing and printing anirnal fibers such as wobl, @ilk 6,iid leather. Due to the f@,ct that the sai'd dyestuffs ate -dbrived ftoiii ah 6ith6-h)@droxydiazo compound they are capbble of forming complex metal compoimds, for instance, with the rnetals copper, coba;lt, nickel, iron, chromium, vanadium, manganese. Many of the foregoing dyestuffs yield -Very -@aluable complex metal compounds if treated in substance with agents yielding metal. This is especially true of those dyestuffs which contain inore than two sulfonic acid grou-ps, for in to@nce those derived from two edupling c6mpdnents l@elonging to the group of hydroxynaphthalene disulfonic acid coupling componeiits. With other dyestuff@ 21427,537 4 it rnay be more advantageous to eff ect metailization during or, still better, after dyeing according to the known aftertreating methods. With special advantage use may be made of the dyeing methods described in U. S. Patents 2,148,659 and 2,185,905, whereby metallizing is preferably carried out with agents yielding metal which are stable towards alkalies, for instance complex tartrates of copper or other metals. 10 In some cases it may also be useful to treat some dyestuffs as mentioned above in substance with such alkaline metallizing agents. F-urthermore it is possible to make use of complex metal compounds of the dyestuffs according 15 to the present invention for coloring masses, varnishes, lacquers, resins, both artificial and natural, and spinning solutions. Whether it is preferable to produce the aforementioned complex metal compounds on the fi20 ber o@ in substance depends on various properties thereof, inter alia, whether the complex metal coinpbunds are soluble, whether the metal-free dyestliffs possess sufracient affinity for the fiber to be dyed, etc. 26 The following examples illustrate the invention, the parts being by weight unless otherwise stated: Example 1 21.6 parts of 3:3'-dih@rdroxy-4:4'-diaminodi30 phenyl, in the form of its dichlorhydrate, are stirred in 100 parts of water and 12 parts oi conceiltrated hydrochloric acid and is tetrazotized by addition 6f an aqueous solution of 13.8 parts of sodium nittate at 5-8' C. When tetrazotization 35 is compiete, the suspension's cooled to 3' C., neu1 tralized by additibn of 6.4 parts of soda and faltered to obtain the precipitated tetrazo compound. 33 pa@t@ of 2,6-dihydrokynaphthalene are dis40 solved in 200 parts of water iind 11.5 parts of caustic potash in @L stream of nitrogen, and the solutiqii is cooled to 5' C. The filtered tetrazo co:mpound is added, atd coupling is allowed to take lalbce f ' or 4 hours at 5-8' C., then for 24 45 hours at 10--15' C. and, finally until the reaction is complete, at 20-25' C. The reaction mass is tlleh diluted with 500 parts of water, and the new dyestuff is precipitaied by the addition of common salt. 50 It possesses the formula N=N- -N I I 6H 55 ila HO -on and is a greyi'sh-biack pbwder which disso I Ives in @Tater @,hd in 10 percent caustic soda to a blackish 60 blue-violet; in 10 percent soda solution to a, blackish greenish-blue and in egneentrated sulfuric acid to a blue solution. The new dyestuff, when dyed cin cofton and aiter-coppered by a one or a two bath process, yields navy blue shades of 65 very good fastness. Example 2 21.6 parts of 3':31-dihydroxy-4:41-diAniinodiphonyl are tetra7,otized and the reaction inixtute 70 neuttaliz6d and the tetrazo compound filtered (ff. 33 paits of 1:5-dihydroxynaphthaleiie ar-e di8solved in 60 parts of water and 11.2 parts potassium hydroxide and the solution cooled to 3' C. 75 The tetrazg compound prepared'as above is add-
[3]2,427,537- 5 ed and coupling carried out for 3 hours at 3 to 5o C. for 2 hours at 5 to 10' C. for 16 hours at 10 to 15' C. and until termination of the reaction at 20 to 25' C. The coupling mass is then diluted with 500 parts of water and the. dyestuff precipi- 5 tated by the addition of sodium chloride. When dried the new dyestuff is a black powder which yields fast greyish black shades on being dyed and coppered on cotton by either a one or two bath process. 1@ Example 3 21.6 parts of 3:3'-dihydroxy-4:4'-diaminodiphenyl are tetrazotized, the tetrazo compound solved in 100 parts of water and 46 parts by Volume of caustic potash solution of 50 percent byvolume in a nitrogen stream and cooled to 3' C'. The filtered tetrazo compound is added and cOu- 20 pling carried out for 3 hours at 3-5' C. for 2 hours at 5 to 10. C., and for 16 hours at 10 to 20' C. Hereupon the reaction mass is diluted with 500 parts of water at 40' C. and the nevr dyestuff precipitated by the addition of sodium chloride. 25 The dried powder is a black bronzy substance which yields navy blue shades with very good fastness properties on being dyed and coppered on cotton by either a one or two bath process. With the dyestuffs of Examples I to 3 inclusive 30 dyeing is preferably effected in a caustic alkaline dyebath (see Patent No. 21185,905). The same is true with the dyestuifs of Examples 4 to 7 below. Example 4 35 21.6 parts of 3:3'-dihydroxy-4:4'-diaminodiphenyl are tetrazotized and then neutralized and the tetrazo compound filtered off. 33.4 parts of I-amino-7-hydroxynaphthalene 40 are dissolved in 200 parts of water with 5.8 parts of caustic potash and the solution cooled to 5' C. The above mentioned tetrazo compound is added and coupling carried out at first at 5 to 10' C. and then at 10 to 20' C. until termination 45 of the reaction. The couplin.- mass is diluted with 500 parts of water and the new dyestuff precipitated by adding sodium chloride. When dry it is a violet black powder which yields grey shades which have very good fastness 50 properties on being dyed and coppered on cotton by either one or two bath process. ExamPle 5 21.6 parts of 3:3'-dihydroxY-4:4'-diaminodi- 55 phenyl are tetrazotized as in Example 4 and Mtered off. 32.8 parts of 2-amino-7-liydroxynaphthalene are dissolved in 240 parts of water and 23.2 parts by volume of caustic soda solution of 30 percent 60 NAOH in a nitrogen stream and cooled to 5' C. The above mentioned tetrazo compound is then added and coupling carried out for 4 hours at 5 to 8' C. for 16 hours at 10 to 15' C. and to complete the reaction for 48 hours at 20 to 25- C. 65 Hereupon the coupiing rnass is diluted with 800 parts of water and the dyestuff precipitated by the addition of sodium chloride. When dry it is a dark powder whir-h yields fast navy blue shades on being dyed and coP- 70 Pered on cotton by either a one or two bath process. stead of the 2-amino-7 Similar navy blue shades are obtained if, in-hydroxynaphthalene, 2- amino-6-hydroxynaphthalene is used. 75 6 Example 6 21.6 parts of 3:3'-dihydroxy-4:4'-diaminodiphenyl are tetrazotized and the neutralized tetrazo compound filtered off. 49 parts of 2:6-dihydroxynaphthalene-monoglycerine ether are dissolved in 100 parts of water and 23 parts of caustic potash. The mixture is cooled to 3' C. and the above mentioned tetrazo compound is added and coupling carried out for 3 hours at 3-5o C., for 2 hours at 5-10' C., for 16 hours at 10-151 C. and until the termination of the reaction at 20 to 25' C. Hereupon it is diluted vvith 800 parts of water at 401 C., the dyestuff Precipitated by adding sodium chloride, with acetic acid of 25 percent strength, filtered off, and washed with water. The new dyestuff when dry is a violet-black powder insoluble in water. When dissolved i-n soda of 10 percent strength and in concentrated sulfuric acid, it yields a blue and when dissolved in caustic soda solution of 10 percent strength it yields a blackish red solution. It produces navy blue shades of very good fastness properties on being dyed and coppered on cotton by either a one or two bath process. Example 7 21.6 parts of 3:3'-dihydroxybenzidine are tetrazotized in known manner in the presence of hydrochloric acid with sodium nitrite. The crystalline precipitated tetrazo compound is added at 5' C. to a solution of 44.6 parts of 1-naplithol-8-sulfonamide in 36 parts by volume of a caustic potash solution of 50 percent by weight KOI-1. The temperatiire increases spontaneously to 30' C. Coupling is carried out for two days at 25 to 30', then the coupling mixture is diluted with 800 parts of hot water and after boiling for a short period the dyestuff is salted out. The dyestuff is filtered off and after drying represents a dark green bronzy powder which dissolves in water and cold soda solution to a bordeaux red, in hot soda solution and Caustic alkalies to a violet and in concentrated sulfuric acid to a greenish blue solution. It yields navy blue shades which are fast to washing and to light on being dyed and coppered on vegetable fibers by either a one or two bath process. Example 8 2.5 parts of the dyestuff ob ' tained according to Example 7 are dissolved hot in 250 parts of water with the addition of a little caustic soda solution. This solution is added to a dye bath consisting of t2OOO parts of water and 2 parts of sodium hydroxide. At 50' C. 100 parts of well wi@tted c6tton are entered and the temperature raised to 95' C. within half an hour, and then 30 parts of Glauber's salt a-re added. After dyeing for about % of an hour at this temperature the bath is allowed to cool to 80' C., and then 2 parts of a complex copper sodium tartrate are added and coppering carried out for half an hour at from 80 to 90' C. The cot4bon is well rinsed and if necessary soaped. It is dyed a fast navy blue. It is further to be understood that the terin "hydroxide of the alkali metal series" includes aqueous solutions of ammonia. What we
