[1]Patentid July 21, 1942 2 1 2 9 0 , 4 3 5 .UNITED STATES PATENT OFFI CE 21290,435 QUINHYDRONES FROM VAT DYESTUF7S AND PROCESS OF MAKING SAME Eduard Kambli, Basel, Ernst Stoecklin, Binningen, and Richard Tobler, Riehen, Switzer land, assignors to the firm of Society -of Chemical Industry in Basle, Basel, Switzerland No Drawing. Application December 5, 1938, Serial No. 244,130. In Switierland December 6, 1937. 3 Claims. (Cl. 260-331) It is known that benzoquinone as well as various other quinones of simple composition can be con verted into quinhydrones. These quinhydro nes are for the most part to be regarded as mol ecular compounds of the quinone and the 5 corr esponding hydroquinone, that is to say quinon e in which both keto-groups have been reduc ed to hydroxyl groups. These quirihydrones may be obtained, for example, by causing a quinon e to react with a hydr6quinone, in many cases 110 also b5@ partial reduction of the quinone or partial oxidation of the hydroquinone, that is to say in general by partial change of the stage of oxid ation of the bne constituent in the quinhydro ne. It has also been suggesibd that quinhy- 15 dro nes are not molecular compounds but inter- 1 med iate stages in mono-moiecular form between the compound containing at least two ketogro ups'and that compound in which the ketogro ups are reduced to hydroxyl groups. What- 20 eve r the view. as to the constitution of the qulnhydro nes, t4e possibilities for making them remain the same. This invention relates to the manufacture of new and valuable quinhydrones from quinones in 215 an analogous manner by using vat dye@tuffs as quin ones. By the process of the Invention quinhyd rone-like comt)ounds of vat dyestuffs are mad e b@ causing vat dyestuffs to act upon leucocom pounds of vat dyestuffs or by partially re- 30 duci ng vat dyestuffs or partially oxidizing leucovat dyestuffs. It may be assumed in ihis connect ion that intermediately the one component is formed from the other and thereupon enters into reaction with the latter. 35 As vat dyestuffs which may be converted into quin hydrones by this Invention there come first into question tho@e which contain at least two keto -groups, for instance indigoid va I t dyestuffs and anthraquinone dyestuffs.@ By vat dyestuffs 40 ait here meant the generally usual dyestuffs whi ch dye in the vat in a commercially practicable way. Am ong the vat dyestuffs which are suitable may be named from among the bis-Indolindi- 45 goid s, indolthionaphthene-indigoids, bis - thionap hthene-indigoids and naphthalene-indol-indigo ids, especially those which have one, and pref erably more, substituents@ which term here incl udes fused-on ringg as in, for instance, 50 4:5: 4':5' - dibenzathioindigo (=2:1:2':l' - naphththi oindigo). Among the anthraquinone vat dye stuffs those are especially suitable for obtaining quinhydrones which contain substituents, for inst ance halogen, methoxy, amino- and substi- 55 tuted amino-groups and/or more highly condensed ring systems. There also come into question dyestuffs which contain besides the anthraquinone nucleus which lends the capacity for being vatted or besides a more highly condensed, if desired heterocyclic ring system of similar function, also fused-bn carbazole rings or other 5membered rings or even acridone ring@s as well as other heterocyclic conflgurations. From- these dyestuffs quinhydrones may be obtained, for example, by causing the dyestuff to act upon its leuco compound. In many cases the dyestuff may be partially reduced, that is to say may be treated with a reducing agent of lnsufflcient quantity for complete reduction or may be treated under such conditions that complete reduction does not occur. It Is advantageous to operate in aqueous medium in, which by maintaining an alkaline, for instance, a caustic alkaline reaction the leuco-compound of the vat dyestuff is soluble and can act especially easily on the vat dyestuff suspended in the solution, preferably in a flnely subdivided state. - The occurrence of a reaction it generally to be detected by a change of colour, since the quinhydrones are differently coloured from the corresponding dyestuffs and leuco-compounds analogously to the difference in colour between benzoquinone and hydroquinone as compared with the quinhydrone formed therefrom. In making the quinhydrones It Is often necessary to adjust the temperature of reaction and the hydrogen ion concentration of the reaction medium in suitable relation to each other, since in the case of ivarious vat dyestuffs the opti@mum conditions for quinhydrone formation vary considerably. As a rule it Is Possible to operate at a raised temperature, @for example@ about 40-80' C., that is to.-say at a temperature normallyused for the complete vatting of the dyestuff. In many cases, however, lower temperatures, about room temp4erature, or higher temperatures, for exampie even above 100' C. when non-aqueous solvent8 are used, are more advantageous. In most cases the use of aqueous alkaline media@@ is recommended, for instance@ alkali hydroxides, if desired at higher or lower concentration than is usual for vatting, or even alkali@ carbonate or alkali sulfldi@ solution or a solution of ammonia or organic base, for instance an alkylarnine or @an alkanolamine. Alternatively, however, it is possible to use orgahic solvents, for instance alcohol, with or without addition of water In presence or absence of an agent of alkaline action. This is especially to be recommended
[2]2 2,290,435 when, as in the case of the known substituted thio-indigos, the quinhydrone is decompcsed into its components by alkalis, so that it cannot be produced in presence of alkali. In many cases there is obtained not only a 5 quinhy&one which contains only one dyestuff when a vat dyestuff is combined with its leuco compound, but also a mixed quinhydrone by combination of a vat dyestuff with a leuco compound of another vat dyestuff, this especiahy being the 0 case when the two dyestuffs have a similar capacity for reduction. When the choice of vat dyestuffs or t.heir conditions of reactiqn has not been suitable either no reaction occurs or there is a vice ve@sa vatting in that the leuco-com15 pound of the one dyestuff reduces the other dyestuff to its leuco-compound and is at the same time itself oxidized to the dyestuff. On the other hand, with many dyestuffs, especially those which belong to the same group of dyestuffs and 20 do not differ substantially iri molecular weight, for instance differ only by about 50 units or less, t-he production of mixed quinhydrones Is possible under the same conditions as in the case of quinhy&ones containing only one dyestuff. Exam25 ples of this are 6:6'-diethoxy-thio-indigo, 4:4'- dimethyl-6:6'-dichloro-thio-indigo and 4:5:4:151- dibenzothio-indigo. The quinhydrones made from vat dyestuffs by the process of this invention are generally 30 Precipitated In fine crystalline form; the preparation frequently exhibits under thle microscope a pronounced crystauine form.,, @@'Mey are, as already stated, in general differently or more deeply colored than are the corresponding dye35 stuffs. They are very sparingly soluble tO insoluble in water or organic solvents. They rnay be used for dyeing for example in the form in which they are produced or they may- be isolated 40 by filtration, if desired with exclusion, of air and/or after treatment with, acid, then washed to remove the reaction medium. In many cases the quinhydrones contain chemically combined alkali which cannot be removed by washing with water but only by treatment with acids, for in45 stance acetic acid, formic acid or mineral acid, if desired with application of heat. 7bis treatment often changes the color of the quinhydrone but in most cases without a recognizable change of crystalline form. 50 The quinhydrones obtained, especially those which have been treated with acid, have considerable stability. In spite of their crystalune condition they can be vatted even without mechaniCal pretreatment, such as grinding, extraordi5,3 narily easily and In this respect present substantial advantage as compared with the parent vat dyestuffs. In consequence of their affinity for vegetable and animal fibres, the quinhydrones may be used with advantage In all dyeing processes in which the non-reduced dyestuff is 60 brought onto the fiber previous to the vatting. The quinhydr6nes by long standing in, for example, alkaline aqueous suspension, or by heating such a suspension, if desired with access of air or in presence of an oxygen agent, may be 6-5 changed in such a manner that at least part of the vat dyestuff Is regenerated and precipite@ted in very finely subdivided state very@suitable for dyeing purposes. 76 The following examples illustrate the invention, the parts being by weight: Example 1 60-65' C. in 100. parts of alcohol. By introducing airwhile@stirring the quinhydrone is preclpitated in the form of vcilet-black crystals. After cooling and futering the crystals are washed with alcohol and dried. There are obtained 4.7 parts of a violet-black sandy crystalline powder soluble in concentrated sulfuric acid to a green solution and dyeing cotton in a yellowish green vat rose tints typical of thio-indigo. When the crystauine powder is heated with water to which a little caustic soda lye has been added the quinhydrone is split, that Is to say there is produced a suspension of thloindigo in the vat solution of this dyestuff . In spite of its undoubted crystalline condition the violet-black quinhydrones can be vatted by means of hydrosulffte and caustic soda lye very quickly and completely. Example 2 1 part of leuco-thio-indigo is dissolved in an atmosphere of hydrogen in 100 parts of glacial acetic acid at 60-65' C. By adding by drops a solution of sodium bichromate in acetic acid of 70 per cent strength the originally red thioindigo -is transiently @ reproduced. If, however, the proportion of chromic acid is so selected that there is added 1/2 atom of oxygen per 1 mol leuco-thio-indigo, there Is obtained. a product which agrees fully with that described in Example 1, namely the violet-black quinhydrone@ instead of a sodium bichromate solution there may be 'used another oxidizing agent, for instance a solution of potassium permanganate in acetic acid of about 70 per cent strength. Exainple 3 itto a s I olution prepared in an atmosphere of hydrogen kt 110-1151 C., of 16 parts of leuco-thioindigo in 800 parts of chlorob@nz6ne there are stirred 14 parts of thio-indigo. After heating for 8 hours at 1101 C. in an atmospher6 of hydrogen the whole is allowed to Cooi to about 600 C. and filtered; the violet-black crystalline quinhydrone (28- 29parts) on@thefllteriswashed with chlorobenzene and dried. It agrees fwly in properties with the product described in Example 1. That the violet-black crystalline prod@ct is in fact a quinhydrone-Iike addition compound of leuco-thio-indigo and thio-indigo in the relation 1:1 is proved, for example, by its reduction with nickel and hydrogen. In comparison with thio-indigo there is corisumed,for complete conversion into the leuco-compqund only half as much hydrogen. Example 4 Into a solution beitring.an atmosphere of hydrogen at a mised temperature of 16 parts of leuco-6:61-diethoiy.-thio-indigo in a mixture of 400 oarts of alcohol, 450 parts of water and 35 parts of caustic soda lye of 30' B6. there Is Introduced a suspension made by grinding together 8 parts of 6:6'-diethoxy-thio-indigo and 80 parts of alcohol and flnally 190 parts of I caustic soda lye of 30' B6. are added. There is immediately formed a dark brown addition product.' After stirring for 1/2 hour in @an atmosphere of hydrogen at 65-70' C., the whole is cooled to about 20' C. and filtered; for removing the excess of leuco-compound which has not entered into reaction the solid matter is extracted with much water which has been freed from oxygen by boiling while introducing hydrogen and then 5 parts of leuco-thio-indigo are dissolved at 75 c(>oling. After drying in a current of hydrogen
[3]2,290,435 i)f 70-90' C. there are obtained per 8 parts of dyestuff 16 parts of dark brown qtiinhydrone which may be ground to a heavy sandy powder. It dissolves to a violet solution in concentrated sulfuric acid and dyes cotton in a greenish yel- 5 low vat the orange,tints characteristic of the dyeings with 6:6'-diethoxy-thio-indigo. When heated with water the product is split with formation of extremely fiiie flocks from the original heavy sandy product. 10 This brown quinhydrone contains besides the dyestuff components a small proportion of chemically bound sodium which in the splitting reaction with water gives rise to an alkaline reaction to phenolphthalein of the aqueous phase. Instead 15 of operating with a large excess of the leucocompound as described in this and the following examples it is also possible to use a leuco-compound and a dyestuff In molecular proportion of 1: 1 in the reactlon. 20 Example 5 After 20 parts of 4:4'-dimethyl-6:6'-dichlorothio-indigo suspended in a mixture of 1000 parts of alcohol and 20 parts of caustic soda lye of 30' 25 B6. have been converted into the leuco-compound by means of a nickel catalyst and hydrogen the catalyst Is removed by ffltration of the solution in an atmosphere of hydrogen,, into this solution there is introduced a paste made In the mill from 50 8 parts of 4:4'-diinethyl-6:6'-dichloro-thio-indigo, 100 parts of water and 5 parts of caustic soda lye of 30' B6. and immediately following 350 parts of caustic soda lye of 30' B,6. are added. The originally. red color of the mixture passes 35 rapidly to brown. ' After stirring for 1/2 hour at about 700 C. in aii atmosphere of hydrogen the whole Is cooled, flltered, and for the purpose of removing the excess of leuco-compound which has not entered into reaction the solid matter iS 40 extracted with much cold wat6r which has been boiled while passing through a current of hydrogen and then cooled. The somewhat reddish dark brown quinhydrone (16 parts) which, after having been dried in a current of hydrogen may be ground to a heavy sandy powder, dissolves to 45 a reddish violet solution In concentrated sulfuric acid and dyes cotton in a greenish yellow vat the known brilliant rose tints of .4:4'-dimethyl6:6'-dichlorothio-indigo. 50 The behaviour of this quinhydrone when it is spht with hot water is similar to that of the product of Example 4. 'ntration of the alkali liberated by the splitting discloses the presence of one atom of alkali metal in the,quinhyd[rone molecule. 55 Example 6 Into the solution of 16 parts of leuco-6:6'-diethoxythio-indigo made and filtered as described in Example 4 there are added 190 parts of caus- 60 tic soda lye of 301 B6. and then in an atmosphere of hydrogen a paste made by grinding /8 parts of 4:4'-dimethyl-6:6'-dichlorothio-indigo with 100 parts of alcohol ' A dark brown suspension is thus formed which, after stirring for 1/2 hour at 70-75' 6.5 C., is cooled to about 20' C., filtered in an atmosphere of hydrogen and the solid niatter washed . with much water, which has been freed from air by boiling with passage of hydrogen, and dried . at 80-100' C. 16 parts of a brown-violet quin- 70 hyd rone are obtained wbich may be ground to a hea vy sandy powder: excess of unchanged leuco6:6'- diethoxy,thio-indigo remains in the filtrate. This quinhydrone dissolves in a solution of concent rated sulfuric acid to a violet solution and 75 dyes cotton In a greenish-yellow vat yehowish scarlet tints. When the heavy sandy powder is split by heating it with water there is produced a finely flocculant suspension of the products, the aqueous phase giving alkaline reaction to phenoiphthalein. A quinhydrone of similar properties which dyes cotton bluish-scarlet tints is obtained In analogous manner by heating together 4:4'-dimethyl6 :6'-dl,cblorothio-indigo In the leuco form and 6:6'-diethoxy-thio-indigo. Example 7 16 parts of leuco-6:6'-diethoxy-thlo-indi@o are dissolved as described in Example 4 and after filtration In an atmosphere of hydrogen there are added 190 parts of caustic soda lYe of 30' B.6. and a paste made by grinding 8 parts ofbis-2L:lnaphththio-indigo with 80 parts of alcohol. After stirring for Y2 hour at 70-75, C. th6 dark brown suspension Is cooled to about 20' C., flltered In an atmosphere of hydrogen and the solid matter washed with much water which has been boiled with passage of hydrogen and again cooled; this removes the leuco-coriipound which has not entered into reaction, and the pioduct may then be dried in a current of hydrogen at 80-100' C. The dark brown quinhydrone (15-16 parts) thus obtain6d dissolves to a blue solution In concentrated sulfuric acid axid dyes cotton in an orange vat red-brown tints. By sphtting the dark browri quinhydrone by heating it with water there is produced a brighter reddish brown suspen,,,ion of the products on splitting. Example 8 384 parts of 6:61-diethoxythio-indigo and 386 parts of a leuco-compound made in usual me@nner from 6:61-diethoxytMo-indigo are stirred to-, gether with 3200 parts of water and 1000 parts of caustic soda lye of 30 per cent strength to produce iL uniform magma,; thls is heated while stirring well at 750 C. untll the originally orange paste has changed Into a finely crystahine brownblack magnia. When the reaction is complete, the mass Is cooled to th.e oidinary temp6rature. The mass In this form may be used directly for preparing a, stock vat and dyes cotton in a redyellow vat pure orange fast tints. Instead of the 6,:6'-diethoxytldo-indigo and the leuco-compound of 6'.61-diethoxythioindigo used in this example, there may be used another indigoid vat dyestuff or its leucocompound, for instance 4:41-;dimethyl-6:6'- dichlorothio-indigo; there is thus obtained a product whi6h is vatted easily and,dyes cotton In this vat similar tints to those of the corresponding parent dyestuff. Example 9 386 parts of the leuco-compound of 6:6'-diethoxythio-indigo and 393 parts of 4:41- dimethyl6:6'-dichlorothio-Indigo' are stirred with 3200 parts of water and 1000 patts of caustic soda lye of 30 per cent strength to produce a uniforin magma; the mass is . then heated while@ stirring well to 751 C. and maintained at this. temperature until the originally red mass has changed into a flnely crystailine brown-black magma. Wben re.action Is complete, tbe, whole is cooled to the ordinary temperature. 'Me mixture may be used in this form directly for preparing a stock vat. It dyes cotton in a red,- yellow vat pure scarl,et tints. Example 1,0 384 parts of 6:6'-diethoxythio-indigo are stirred
[4]4 2,290,435 with 800 parts of water and 200 parts of caustic soda lye of 30 per cent strength to form a uniform ma.@ma; after addition of 110 parts of sodium hydrosulfite (about 80 @er cent strength) and while thoroughly stirring, the whole is heat- 5 ed to 75' C. and kept at this temperature until t,he originally orange mass has become a uniform finely crystalline brown magma; this happens after 2-3 hours. When the reaction is complete, the mass is cooled to ordinary temperature. 10 . This mixture, which shows a trace of alkalinity to phenolphthalein, may be used directly for preparing a stock vat; it dyes cotton fast orange tints. The reaction occurs substantially more quickly 15 if in this example an excess of caustic soda lye, for instance 260 parts, is used. In this case the alkaline mixtuxe obtained is somewhat darker in color than that described above. If the mixtures obtained according to this ex- 20 ample, are m@ixed at 15-201 C. with hydrochloric acid until the reaction is neutral or feebly acid, the colour changes after some time, which may be shortened by gentle heatin,a, to red-orange, and there is obtained by filtering, washing and 25 drying a red product that dyes cotton in a vat fast orange tints. Example 11 40.6 parts of the dyestuff obtained by con- 30 densation of 1:5-dichloro-7-methoxyisatin-(xchloride and 4-chloro-l-hydroxynaphthalene are made into a paste with 150 parts of caustic soda lye of 30 per cent strength and water and after the addition of 11 parts of sodium,hydrosulfite 35 of about 80 per cent strength the paste is heated to 70-80' C. After the suspension has been stirred for some minutes at this temperature it is cooled, filtered and the solid matter washed with water. This product is a brown-black pow- 40 der soluble in concentrated sulfuric acid to a blue-green solution and dyeing cotton in a yellowish-green vat pure blue tints. It is oxidized when heated or allowed to stand for a long time in the air. A product having similar properties Is obtained 45 when there are used as parent material 49.5 parts of the dyestuff obtained by condensing 4-chloro5-bromo-7-methoxyisatin - . - chloride with 4- bromo-l-hydroxynaphthalene. r'O Example 12 384 parts of 6:6'-diethoxythio-indigo and 386 parts of a leuco-compound of 6:6'-diethoxythioindigo made in the usual manner are stirred to , form a uniform magma with 3200 parts of water .5 and 1000 parts of caustic soda lye of 30 per 6ent strength; this mixture Is heated while stirring well to 75' C. at which temperature it is maintained until the originally orange paste has become a fine crystalline brown black magma, 60 which occurs in about 30 minutes. When the reaction is complete, the mass is cooled at the ordinary temperature and then neutralized with 340 p arts of isobutyric acid. Tte product is vat- 65 ted in this pasty form very easily and dyes cotton in a red-yellow vat pure orange fast tints. The paste may also be dried preferably in the, vacuum or in an atomiser, whereby a powder is obtained which is also suitable for dyeing. The 340 parts of isobutyric acid named in this do example may be exchanged for an equivalent quantity of another acid, for instance sulfuric acid, hydrochloric acid, acetic acid or the like. However. it is of especial advantage that the acid 75 us-,d should lead to the formation of salts having hydrotropic properties. Such neutralised dyestuff pastes are suitable especially for dyeing by the i)adding method. Example 13 21 parts of flavanthrene (Colour Index No. 1118) are suspended in a mixture of 700 parts of alcohol, 150 parts of wat@r and 50 parts of caustic soda lye of 10 per cent strength, and the suspension is shaken in the presence of a nickel catalyst with hydrogen until the absorption of hydrogen amounts to 1 mol per 1 mol of flavanthrene. After removing the catalyst by filtration at 35-401 C. in a'n atmospliere of hydrogen, there is added to the deep violet-blue solution of the dihydroflavanthrene a dyestuff paste made from 10 parts 6f flavanthrene and 100 parts of alcohol, whereupon the whole is heated for 1/2 hour at 70-75' C. while stirring, then cooled to 40-45' C. and filtered with suction in an atmosphere of hydrogen; the solid matter, is washed with much air-free water and dried at 80-100' C. There are obtained 21 parts of a brown quinhydrone besides unchanged dihydroflavanthrene which has not taken part in the reaction and is In the flltrate. The qWnhydrone dissolves in concentrat6d'sulfuric acid to an olive-green solution and dyes cotton in a dark blue violet vat yellow tints. When heated with water it is split, the sandy brown powder gradually becoming a finely flocculant yellow suspension. By stirring the brown quinhydrone, which has been washed free from alkali and then covered with dilute hydrochloric acid, with hydrochloric acid of I per cent strength in an indifferent atmosphere, for instance one of hydrogen, at 50-601 C., the suspension becomes green without @ changing tiie crystalfine form characteristic of the qwnhydrone. Example 14 23 parts of dibenzanthrone itre convertbd Into the dihydro-compound in the manner described in Example 13 in the presence of nickel catalyst. After flltering the catalyst there Is introduced in an atriiosphere of hydrogeii into the dark reddish violet solution a dyestuff paste made by grinding 10 parts of dibenzanthrone with 100 parts of alcohol and the whole is stirred for 1/2 hour at 70-75, C. The suspension cooled to 40' C. Is then flltered with suction and the solid matter washed with air-free water and dried in a current of hydrogen at 80-100' C. There are obtained 20 parts of a brown-black quinhydrone which, when rubbed shows a crystalline fracture of bronze lustre, in addition to unchanged dih-vdrodibenzanthrone which Is in the filtrate. The quinhydrone dissolves to a violet solution in concentrated sulfuric acid and dyes cotton In a violet vat reddish blue tints. Example 15 20 parts of 4:5:41:5'-dibenzothio-indigo are suspended in 500 part.@ of alcohol, and after,addition of 50 parts of caustic soda lye of 10 per cent strength converted into the leuco-compound by shaking with hydrogen In presence of a nickel catalyst. The solutibn freed from catalyst by filtration in an atmosphere of hydrogen is mixed with 60 parts of caustic soda lye of 30 per cent strength and then stirred at 65-70, C. for 1/2 hour in an atmosphere of hydrogen with a paste made from 10 parts of 4:5:4':5'- dibenzothioindigo, 50 parts of alcohol and 50 parts of water.
