48 MORGAN AND PICKARD : PRODUCTION OF PARA-DIAZOIMIDESVI.-The Production of para-Diaxoimides from Alkyl-and Aryl-sulphonyl-~ara-dia~~~~es. A GeneralReaction.By GILBERT T. MORGAN and JOSEPH A. PICKARD, B.Sc., A.R.C.S.CERTAIN derivatives of pphenylenediamine give rise to diazoniumsalts, from which diazoimines or diazoimides may be produced byinternal condensation. The earliest known pdiazoimine is theexplosive phenyl-p-diazoiminobenzene, C,H,*N*C,H,*N,, discoveredby Ikuta (Annulem, 1888, 243, ZSZ), and afterwards studied byHantzsch (Ber., 1902, 35, 895). In 1904, one of us, in conjunctionwith I?. M. G. Micklethwait, obtained the first p-diazoimide fromcamphor-j?-sulphonyl-pphenylenedismine (Trans., 1905, 87, 74),and subsequently showed that benzenesulphonyl-pphenylenediamineand its homologues readily yield arylsulphonyl-p-phenylenediazo-imides (Trans., 1905, 87, 921, 1302).Although these diazoimides are moderately stable substances, yetcomparative experiments proved that they and Ikuta’s unstablediazoimine are members of the same class of diazo-compounds.This relationship was demonstrated by the preparation of a con-necting series of mono-, di-, and tri-nitrophenyl-p-phenylenediazo-imines, the stability of which increases as nitro-groups are intro-duced successively into the molecule of p-aminodiphenylamine(Trans., 1908, 93, 605).These p-diazoimines and p-diazoimides are distinguished from theo-diazoimines and o-diazoimides by their intense colour, generallyeither yellow or orange, and by their very reactive character.When treated with cold concentrated mineral acids, they re-generate the corresponding diazoniurn salts, and with phenols andaromatic amines they couple additively to form azo-derivatives.On account of these properties, some of the more readily prepareFROM ALKTL- AND ARPL-SULPHONY L-PARA-DIAMINES.49members of the group can be turned to account in the productionof azo-colouring matters ( J . Soc. Dyers, 1909, 25, 107).These results render plausible the view that the property offorming p-diazoimino-compounds is possessed by all derivatives ofp-phenylenediamine having the formula RNH*C6H,*NH2, and evenby the base itself, but more experimental evidence would berequired before it could be definitely stated that the reaction isa perfectly general one.By the experiments described in the present communication wehave endeavoured t o show that, in all probability, the reactionis general for all organic sulphonyl derivatives of pphenylene-diamine. This demonstration may be conveniently divided intothree stages.I.-Para-diazoimides Containing Arylpolysulphoql Groups.The conversion of benzene1 : 3-disulphonylbis-p-phenylenedi-amine into the corresponding bis-diazoipide has already beenaccomplished (Trans., 1905, 87, 1309), and, in the present instance,the case of benzene-1 : 3 : 5-trisulphonylter-p-phenglenediamine (I)has been examined as a typical example of an amide derived froma complex polysulphonic acid.Apart from certain practical difficulties encountered in thepreparation of the triamine, it was found that the conversion ofthis base into b enzene-1 : 3 : 5-trisulphonylter-p-phenylenediazoimide(11) is a comparatively simple matter:(1.) (11.1This result justifies the conclusion that the production of thediazoimide is independent of the number of sulphonyl groupspresent in the molecule of the aromatic aminosulphonamide.II.--Par&diazo imid es Containing Mixed A ryl-at k ylsulphorylGroups.Former experiments on the constitution of diazoimides led tothe interesting observation that o-benzenesulphonyl-o-benzylene-VOL.XCVII. fjO MORGAN AND PICKBRD : PRODUCTIOX OF PARA-DIAZOIMIDESdiamine (111) gives rise to a diazoimide (IV) of mixed type (Trans.,1906, 89, 1162):but as the substituent groups of this product differ in theirorientation from those of the p-diazoimides, we now endeavouredt o obtain a mixed aryl-alkyl derivative of the general type bystarting from toluene-w-sulphonyl-p-nitroaniiine (V).The pre-paration of this substance presented some difficulty, however, owingto the circumstance that toluene-w-sulphonyl chloride, unlike thearylsulphonyl chlorides, does not condense satisfactorily withp-nitroaniline in pyridine or boiling toluene. The addition oftriethylamine to the latter solvent was finally found to bring aboutthe desired result, the following condensation then taking placealmost quantitatively :C,H,*CH,*SO,~Cl + H*iNH*C,H,*N02 - ~ NH<S02*CH,*C6H5iN( C2H,) s/ C, H,* NO,(T. 1......................Toluene-w-sulphonyl-p-phenylenedianaine (VI), prepared by re-ducing the nitro-compound (V), when successively diazotised andtreated with aqueous sodium acetate, furnishes toluene-w-sulphonyl-p-phenylenediazoimie (VII) :(TI.1 (VII.)This substance, containing a. mixed aromatic-alkyl group, behaveslike a typical pdiazoimide; it separates in bright yellow, sparinglysoluble needles, regenerates the diazonium chloride with cold con-centrated hydrochloric acid, and couples with phenols and aromaticamines, yielding azo-derivatives.111.-Para-diazoimides Containing Alkylsulphonyi? Groups.The existence of camphor-j3-sulphonyl-p-phenylenediazoimide(Zoc. cit.) shows that the presence of an aromatic group attachedto the sulphur atom is not an essential condition for the formationof a diazoimide of this type, and accordingly we took steps toobtain diazoimino-derivatives containing the simplest alkyl-sulphonyl groupsFROM ALKYL- AND ARYL-SULPHONYL-PARA-DIAMISES.Yj 1Methionic chloride condenses readily with pnitroaniline, yield-ing met hanedisdphonyl b is-p-nit roaniline, CH2( SO2*NH*C6H,*N0,),,which, on reduction, gives rise to methanedisulphonylb is-p-phenylenediamine (VIII), an amphoteric subst.ance, yielding bothit sodium derivative and a dihydrochloride. The latter compound,when diazotised, furnishes a fairly stable bisdiazonkm chloride,the colourless soIution of which turns yellow on the addition ofaqueous sodium acetate, thus indicating the formation of a diazo-imide.Met hanediszclphoity I b is-p-phenylenediazoimide (IX) is, however,isolated only when either the dry diazonium.chloride is dustedinto concentrated aqueous sodium acetate, or when crystals of thissalt are added t o a strong solution of the diazonium compound:(VIII.)This diazoimide has the physical and chemical properties whichcharacterise the group, but is less stable than the more complexmembers. It is somewhat soluble in water, although the solubilityis considerably diminished in the dried specimens.The production of the simplest possible alkylsulphonyl-p-phenylenediazoimide has been accomplished by the followingseries of operations. Methanesulphonyl-p-nitroaniline, produced bycondensing methanesulphonyl chloride and p-nitroaniline in thepresence of triethylamine, yields, on reduction, met?mmesuZphonyZ-p-phenylenediamine (X).The diazonium chloride and sulphate ofthis base are colourless salts, which give yellow solutions of thediazoimide on treatment with sodium acetate :- -(X. 1 (XI.)Met hanesulphonyl-p-phenylenediazoimide (XI) is soluble inwater, and as it rapidly decomposes into a resinous product evenin cold aqueous solutions, its isolation in the solid state is a matterof considerable difficulty. When silver nitrite is introduced intoa solution of methanesulphonyl-p-phenylenediamine hydrochloride,silver chloride is precipitated, and the solution then contains onlythe diazoimide, which may be obtained by evaporating to drynessE 58 AIORQAN AND PICKbRI) : PRODIJCTION OF PA RA-DIAZOIMIDESin a vacuum over phosphoric oxide. Unless this evaporation iseffected very rapidly, the product darkens, and some loss of nitrogenis apparent.When sodium nitrite is used in this experiment, thefiltered solution contains molecular proportions of the diazoimideand sodium chloride. The presence of this inorganic salt seemsto increase the stability of the diazoimide, and the solution maybe evaporated to dryness in a vacuum without loss of nitrogen.With the production of the two foregoing diazoimides, containingrespectively methanesixlphonyl and methanedisulphonyl groups, thetask of demonstrating the general character of this chemical changeis completed, and the reaction may be expressed in general termsin accordance with the following symbolical scheme, where R isany alkyl, aromatic, hydroaromatic, or mixed aromatic-alkyl radicle,and x is its valency:The conversion of t.he diazonium chloride into the p-diazoimide isa reversible change, and it is of interest, in connexion with themodern theories of solution, to notice that the reaction probablyoccurs in three or more successive phases.The inverse change isbrought about, not only by mineral acids, but even by acetic acidwhen present in excess, and this result indicates that the firstphase in the direct change is the formation of a diazonium acetate:R*S0,*NH*C6H4*N,C1 + CH,*CO,Na -+R*SO,*NH*C,H,*N,- C0,-CH,,which, in the absence of any considerable excess of free acetic acid,undergoes hydrolysis, the extent to which this second phase occursbeing determined by the concentration of the acetic acid :R-SO2*NH*C,H4*N2*CO,*CH3R*SO;NH-C6H;N2*OH + CH,*CO,H.The hypothetical diazo-hydroxide thus produced is an amphotericsubstance, having an acidic substituent, R*SO,*NH, and a basicgroup, N,*OH, each of which probably exists in solution in associa-tion with a certain characteristic number of water molecules.Butas the sodium acetate solution invariably assumes the yellow colourof the p-diazoimide, one must suppose that a certain proportion ofthis substance is actually formed in solution by the internal con-densation of the hydrated diazo-hydroxide :R*SO,*NH*C,H,*N,*OHThis mode of representing the final phase of the condensation isR*S02*N*C,H,*N2 + (x + y + 1)H20.I--.---.I xH20 YH2FROM ALKYL- AND ARYL-EULPHONYL-PARA-DIAMISES. 53probably true only when R is a complex group of comparativelyhigh molecular weight. In these cases, the precipitation of thepdiazoimide is immediate and practically complete, but when R iga simple alkyl group of low molecular weight, the p-diazoimideexhibits a tendency to remain in solution, probably in the hydratedform :R*SO,*N*C H *N,,zH20.4 1Methanesulphonyl-p-phenylenediazoimide is obtained only onevaporating its solution to dryness under greatly reduced pressure,and methanedisulphonylbis-p-phenylenediazoimide in the moist con-dition dissolves fairly readily in cold water, and becomes much lesssoluble only after desiccation over phosphoric oxide.Further evidence for the existence of hydrated forms of thediazoimides was obtained by F.M. G. Micklethwait, J. M. Hird,and one of us in the study of the arylsulphonylbenzidines. Inthese bases, where the acid and basic substituents are separated bytwo aromatic nuclei, the diazoimide separates with two molecularproportions of water, and has the general formula:R*S02*N*C6H4*C6H4*Nz,2Hz01 I(Trans., 1907, 91, 1509; 1908, 93, 615).The closely allied aromatic diazo-oxides exhibit the samephenomenon; the more complex members of the series separate inanhydrous forms, as, for example, dinitrophenylenediazo-oxide,O*C6H2(N0,),*N2, whereas Hantzsch and Davidson (Bey., 1896,I I29, 1530) found that the simplest member, p-phenylenediazo-oxide,separates with four molecules of water, and can be representedby the formula O*C6H4~N,,4Hz0.In connexion with the existence of hydrated forms of diazo-imines, attention should be directed to an interesting observationmade by the chemists of the Badische Anilin- und Soda-Fabrik(D.R.-P.205037). Acetyl-p-phenylenediamine was diazotised inhydrochloric acid, and the acetyldiazonium chloride hydrolysed bygently heating the solution. The dissolved product was then foundto couple with alkaline B-naphthol much less rapidly than theunhydrolysed acetyl-p-aminobenzenediazonium chloride. Altlioughthe product of hydrolysis was not isolated, it seems probable thatit consists of it hydrated form of p-diazoiminobenzene,1- INH0C6H4*N2,zHzO.1 54 MORGAN AND PICKARD : PRODUCTION OF PARA-DIAZOIMIDESEXPERIMENTAL.I.-Benzene-1 : 3 : 5-trisuZphonp?ter-p-phen~lenediazoim'de.A mixture of benzene-1 : 3 : 5-trisulphonyl chloride (1 mol.) andp-nitroaniline (3 mols.) was boiled in dry pyridine for severalhours, the solvent then removed by evaporation, and the residue,after extraction with water, was boiled with aqueous sodiumcarbonate.The alkaline filtrate, when acidified with dilute hydro-chloric acid, yielded a yellowish-white precipitate, which, afterrepeated crystallisation from methyl alcohol, separated as a white,crystalline powder, and melted at 278O :0.2202 gave 23.6 C.C. N, at 17O and 758.2 mm.0*2100 ,, 0.2162 BaSO,. S=14-15.Benzene-l : 3 : 5-trisulphonylter-p-nitroa?ziline,N=12*58.C2,H,,0,,N6S3 requires N = 12-40 ; s = 14.19 per cent.C6H3(S02*NH0C,H,*N0,),,is a distinctly acidic substance, and on treatment with alcoholicpotash gives a potassium derivative, separating in small, yellowcrystals.When diluted with an equal volume of water, the methyl-alcoholic mother liquors of the preceding compound deposited abrown oil, which gracually solidified t o radiating clusters of stout,yellow prisms.This product, when washed with cold ethyl acetateand crystallised from alcohol, was obtained in odourless, yellowcrystals? insoluble in water or dilute hydrochloric acid, butdissolving in cold aqueous sodium hydroxide to a yellow solutionhaving a strong odour of pyridine :0.1288 gave 12.8 C.C. N, at 2 4 O and 763 mm.This result, which agrees with the formula :N=11*19.C,3Hi,0,1N'5S3 requires N = 11'01 per cent.C6H3( S02*NH * C,H, NO2),* S03H,C,H,N,shows that a certain amount of the chloride,C,H,( S0,*NI<*C6H,oN0,),* So2c1,arises from the interaction of p-nitroaniline and benzene-1 : 3 : 5-tri-sulphonyl chloride, the subsequent action of water in the presenceof pyridine leading to the production of the above pyridine salt.A comparative experiment made with the other nitroanilinesshowed that the ortho-base gave only a small yield of crystallineproduct with benzene1 : 3 : 5-trisulphonyl chloride, whereas themeta-base reacted readily and quantitatively in boiling pyridineto form the following compound.Benzene-l : 3 : 5-trisdphonylter-m-nitroaniZine,C6H3 ( S 0, NH - C,H,*N 0,) 3separated from pyridine by removing the latter with cold dilutehydrochloric acid, was crystallised from 50 per cent.acetic acid,and thus obtained in small, white needles, melting a t 199O:N=12*28. 0.2657 gave 27.4 C.C. N, a t 14O and 767.4 mm.This trisulphonamide is readily soluble in aqueous alkaliBenzene-1 : 3 : 5-t~isuZp?fionyZter-p-p?~en-yZenediamine,C,,H,,0,,N,S3 requires N = 12-40 per cent.hydroxides or glacial acetic acid.C,H3( SO,*NH*C,H,*NH,),,was produced by adding iron filings (10 grams) to benzene-1 : 3 : 5-trisulphonylter-p-nitroaniline suspended in 100 C.C. of warmwater containing 1 C.C. of glacial acetic acid, the mixture beingheated for three hours. Excess of sodium bicarbonate was added,the mixture filtered, and the filtrate acidified with acetic acid,when the triamine separated, the yield being about 50 per cent.When crystallised from water or acetone, the triamine separatedin colourless nodules, and melted a t 256O:0.1580 gave 19.5 C.C.N, at 2 3 O and 775 mm.C24H2404N4S3 requires N = 14.29 per cent.The diazo-solution from 1 gram of base, 30 C.C. of 2N-hydrochloricacid, and 20 per cent. sodium nitrite solution was treated withaqueous sodium acetate until a slight permanent precipitate wasformed. From the filtered solution, excess of sodium acetatedeposited the diazoimide as a light yellow, microcrystalline pre-cipitate, which was washed successively with cold water, alcohol,and ether. The product retained water very tenaciously, its weightbecoming constant only after prolonged drying over sulphuric acidQr phosphoric oxide :N=14*55.0.1923 gave 0.3244 CO, and 0.0502 H,O.0.19880.2011 ,, 0.2235 BaSO,.S=15.26.C = 45.99 ; H = 2-70,N=19*75. ,, 34.8 C.C. N, a t 18O and 757.3 mm.C24H1506N9S3 requires C = 46-37 ; H = 2.43 ; N = 20.32 ;S=15*46 per cent.The filtrate from the diazoimide gave a red coloration withalkaline @-naphthol, showing that the precipitation of the con-densation product was not complete even in the presence of con-siderable excess of sodium acetate.Benzene-1 1 3 : 5-trisuZplion-ylter-p-phenyZened~azoinzide,C,H,(SO,.N*C,H,*N,),,I Iwhich explodes somewhat violently a t 146O, is too insoluble to becrystallised from the ordinary organic solvents; it can be preservedfor an indefinite t'ime in the dark, although on exposure t o lightit rapidly darkens and assumes ilr purple-brown colour.Whe56 MORGAN AND PlCKARD : PRODUCTlON OF PARA-DIAZOIMIDESdissolved in cold hydrochloric acid, the diazoimide is convertedinto diazonium chloride, as may be shown by adding the dilutedsolution to alkaline &naphthol.obtained either in the preceding reaction or by triturating the diazo-imide with &naphthol in the presence of pyridine, separated fromalcohol as a dark red, crystalline powder, melting a t 265-266O :0.1060 gave 10.4 C.C. N, at 21'5O and 762 mm.C,H,,09N9S, requires N = 11.92 per cent.This azo-&naphthol dissolves in concentrated sulphuric acid toa deep red solution; its alkali salts are sparingly soluble in watercontaining alkali hydroxides, and are decomposed by dilute aceticacid.11.-Toluene- o-sulp7~onyl-p-p7~enylened~zoim~e.It was not found possible to condense p-nitroaniline and toluene-w-sulphonyl chloride in boiling toluene, and in warm pyridine thesesubstances interacted to form tarry products.The difficulty wasovercome by dissolving molecular proportions of pnitroaniline,toluene-o-sulphonyl chloride, and triethylamine in toluene, theliquids being first carefully dried over sodium. Afterboiling for two to three hours, the condensation was com-plete, and the solvent wits then removed by evaporation.The residue was extracted repeatedly with boiling aqueoussodium carbonate, and the solution filtered while hot.On cooling, the sparingly soluble orange sodium derivative,C6H,*CH,*SO,*NNa*C6H4*NO,, separated ; this was decomposed a tOo with dilute hydrochloric acid, when the toZuene-o-suZp7~onyZ-p-nitroandine, which first appeared as a pasty, yellow mass, slowlysolidified, and was crystallised from alcohol and water (1 : 4) :N=11.39.0.1452 gave 12.5 C.C.N, a t 15O and 737 mm.0.1075 ,, 0.0868 BaSO,. S=11*09.After repeated crystallisation from dilute alcohol, the sulphon-Toluene-o-szllphonyI-p-p~e?~~lenedianzie,N=9.82.C13Hl,04N,S requires N = 9.60 and S = 10.96 per cent.amide melts at 155O.C6H6* CH,* SO,*NH*C6H,*NH,,was produced in almost quantitative yield by reducing the pre-ceding nitro-compound (4 grams) with iron filings (5 grams) in100 C.C.of 4 per cent. acetic acid. After boiling for thirty minutes,the mixture, rendered alkaline with sodium carbonate, was filtered,when the filtrate deposited white crystals of the base, a furtherquantity being extracted from the residue with alcohol. AfteFROM ALKYL- AND ARY L-SULPHONYL-PARA-DIAMINES, 57crystallisation from this solvent, the base was obtained in acicularprisms, melting at 121-122O :0-1241 gave 11.8 C.C. N, a t 16O and 753.5 mm.C,,H,,O,N,S requires N = 10.69 per cent.This diamine was diazotised in 6 per cent. hydrochloric acid,and the filtered solution treated with excess of aqueous sodiumacetate. The liquid became yellow, and subsequently depositedlemon-yellow needles of the diazoimide. These were washed suc-cessively with cold water, alcohol, and ether.The aqueous filtrategave only a slight coloration with 8-naphthol, showing that theprecipitation of diazoimide was complete. The product, a typicaldiazoimide, darkened a t 136O, and decomposed violently a t 1410 :0.1463 gave 0.3061 CO, and 0.0567 H20. C = 57.05 ; H =4.31.0.11360.1279 ,, 0.1056 BaSO,. S=11*33.N = 11.20.,, 15.9 C.C. N, at 18O and 735 mm. N=15.63.C,,H,,O,N,S requires C =57.14 ; H = 4.03 ; N = 15.38 ;S = 11.73 per cent.C6H,*CH2*SO,=N*C,H,*N2,like the arylsulphonyldiazoimides, is practically insoluble in theordinary solvents, but dissolves in cold hydrochloric acid, re-generating the diazonium chloride. Although stable in the dark,i t rapidly darkens on exposure to light, becoming orange, and finallydark brown.Toluene-o-swlphonyl-p-phenylenediazoirnide,I-.--.-- ITolu ene-o-sulphonyl-p-amino b enz eneazo-p-naph t hol,C6€€,*CH2* S02*NH*C6H4*N,*C,,H,*OH,prepared eit.her by triturating the diazoimide with &naphthol andpyridine, or by adding the acid solution of the diazoimide toalkaline @-naphthol, separated from alcohol as a bright red,crystalline powder, melting at 211O :0.2110 gave 19 C.C.N, a t 12O and 763 mm. N = 10.68.C23H1903N3S requires N= 10.10 per cent.[With F. M. G. MICKLETHWAIT.]III.--Methanedisulphonylbis-p-phenylertediazoimide.When methionic chloride * (1 mol.) and p-nitroaniline (2 mols.)were mixed in dry toluene, a vigorous reaction took place, andthe condensation was completed by warming the mixture for a fewminutes. After removing the toluene by evaporation, the residue+ For the specimen of methionic chloride employed in the following experiments,we are indebted t o the liberality of the Farbenfabriken vormals Friedrich Bayer& co58 MORGAN AND PICKARD : PRODUCTION OF PARA-DIAZOIMIDESwas extracted successively with boiling water to removep-nitroaniline, and with aqueous sodium carbonate to dissolvethe met Banedisdphonyl b is-p-nitroaniline, CH,( SO,*NH*C,H,-NO,),.The latter substance was then crystallised from alcohol, when itseparated in transparent, light yellow prisms, melting and decom-posing at 248-249O:0.1607 gave 19.0 C.C.N, a t 25O and 774 mm.0.1871 ,, 0.2216 BaSO,. S=16.27.C,H120,N4S2 requires N = 13.48 ; S = 15.41 per cent.Met hanedisdphonylbis-p-nitroaniline decomposes both soluble andinsoluble carbonates ; its sodium derivative is somewhat sparinglysoluble in cold water.N=13*54.Net hanedisulphonyl b is-p-pheny Zenediamine,CH,(SO,*NH*C,H,*NH,),,was prepared by reducing the preceding compound with iron filingsand 4 per cent. acetic acid.The reduction was completed after twohours' heating, and the mixture, rendered alkaline with sodiumcarbonate, was rapidly filtered. The base, which had passed intothe filtrate in the form of its sodium derivative, was precipitatedwith dilute acetic acid, and crystallised from ethyl acetate, whenit separated in small, colourless needles, melting a t 227O:N=15*72. 0.1505 gave 21.0 C.C. N2 at 26O and 771 mm.0.2036 ,, 0-2691 BaSO,.S=18-15.C,H1,O4N4S, requires N = 15-73 ; S = 17.97 per cent.Methanedisulphonylbis-pphenylenediamine is an amphoteric sub-stance, exhibiting in a remarkable degree the dual properties ofbase and acid. As a base, it forms a dihydrochloride soluble inwater, and dissolving more sparingly in alcohol. As an acid, itdecomposes calcium carbonate and other insoluble carbonates, andforms soluble sodium and even ammonium derivatives.Methanedisulphoizylbis-p-aminob enzenediasonium chloride,CH,( @O2*NH*C,H,*N2C1),.-The foregoing base was suspended in alcohol, concentrated hydro-chloric acid added, and the resulting solution rapidly filtered.Amy1 nitrite was then added. when the diazonium. chloride rapidlyseparated as a light grey, crystalline precipitate, insoluble inalcohol :0.1114 gave 17.6 C.C.N, at 2 2 O and 769 mm.0'2090 ,, 0.1276 AgCl. C1=15.10.Cl3Hl2O4N,C1,S2 requires N = 18.60 ; C1= 15.74 per cent.When prepared in the dark, the diazonium chIoride is almostcolourless, but when exposed t o light in contact with its motherN=18*10FROM ALKYL- AND ARYL-SULPHONY L-PAKA-DIAMINES. 59liqyor, the salt frequently assumes a reddish-brown colour, andbecomes almost insoluble in water.The corresponding diazonium sulphate was produced by diazo-tising the foregoing diamine in dilute sulphuric acid, and, beingless soluble than the diazonium chloride, it was precipitated byalcohol from its aqueous solution, These salts, when dissolved inwater, have an acid reaction.Methanedisulphonylbis-p-anzinob enzenediazonium nit rate,CH,(S0,*NH*C6H,*N2*N03),,and the following substance were obtained in unsuccessful attemptsto prepare the bisdiazoimide.The nitrate was formed by addingsilver nitrate to an aqueous solution of the foregoing diazoniumchloride, and concentrating the filtrate from the silver chlorideover potassium hydroxide under 5 mm. pressure. It separated inpale yellow needles, which, when dry, were somewhat sparinglysoluble in cold water, and decomposed violently a t 156-160°:0.0898 gave 17-7 C.C. N, a t 22O and 766 mm.0.1368 ,, 0.1580 CO, and 0.0365 H,O. C=31.50; H=2*96.C13Hl,01,N8$2 requires C = 30.95 ; H = 2-38 ; N = 22-22 per cent.A carefully purified portion of methanedisulphonylbis-p-phenylenediamine was dissolved in glacial acetic acid, and diazo-tised with ethyl nitrite.The filtered solution, when graduallydiluted with alcohol and ether, deposited a pale yellow, unstablesubstance, which, when rapidly collected and dried, gave analyticaldata corresponding with the diazoamine :N=22*51.0.1134 gave 0.1722 CO, and 0.0452 H,O.0.1324 ,, 22.0 C.C. N, a t l'i0 and 772 mm. N=19*60.C13H130,N,S2 requires C =42.50 ; H= 3.54 ; N = 19.07 per cent.Another portion of the base was dissolved in glacial acetic acid,diazotised with ethyl nitrite, and the solution evaporated to drynessat the ordinary temperature in a vacuum desiccator. The residue,a dark red substance resembling shellac, contained no combinedacetic acid, and only 15-38 per cent.of nitrogen, shomwing t.hat aportion of the diazo-nitrogen had been eliminated duringevaporation. Its composition approximated to that of a diazo-oxide or azo-phenol produced by internal condensation.The colourless aqueous solutions of the bisdiazonium salts, whentreated with excess of sodium acetate, assumed an intense yellowcolour. indicating the formation of the bisdiazoimide, but the sub-stance was not precipitated. After many fruitless attempts t oisolate the bisdiazoimide, it was found possible to precipikab ifiC=41.41; H=4*4360 MORGAN AND PICKAKD : PRODUCTION OF PARA-DIAZOIMIDESeither by adding the solid bisdiazonium chloride to concentratedaqueous sodium acetate or by introducing crystals of the lattersalt into strong aqueous solutions of the bisdiazonium chloride.Thelatter procedure is preferable, because by the former the productpasses through a viscid phase which is obviated by the secondmethod of mixing. The bisdiazoimide separates as an orange-yellow, microcrystalline mass, which, when once segregated, isremarkably insoluble in cold water, and can accordingly bethoroughly washed without serious loss, first with water, and thensuccessively with ether and light petroleum :0.1042 gave 0.1576 CO, and 0.0368 H20. C= 41.26 ; H= 3-87.0.1272 ,, 0.1926 CO, ,, 0'0414 H,O. C=41*29; H=3.61.0.11250.1712 ,, 0.2138 BaSO,. S=17.15.,, 21.9 C.C. N, at 19.5O and 761 mm. N=22.43.Cl3HlOO4N6S2 requires C =41*26 ; H = 2.64 ; N= 22.22 ;S=16#93 per cent.Met hanedisulphon yl b is-p-p h enylenediazoimide,CH,(SO2*N*C,H,*N2)2,1- Idecomposes violently a t 120°, and darkens rapidly on exposure tolight.When triturated with 8-naphthol in the presence ofpyridine, it combined additively with the former, giving rise tomet hanedisulphonyl b is-p-amino b enz eneaso-P-napJb t ho I ,CH,(S02*NH*C,H,*N,~Cl,H,~OH),,which was also produced in the form of its sparingly soluble darkred alkali derivative on adding the bisdiazonium chloride to alkalineP-napht-hol. The free azo-&naphthol is a red powder, varying con-siderably in tint, and only sparingly soluble in the ordinary organicmedia; it melts at 272O:0.1304 gave 14.4 C.C. N, a t 1 5 O and 752 mm. N=12*80.C13H2,0,N,S2 requires N = 12-61 per cent.IV.-Metlianesulphonyl- p-phenylenediazoiniide.The methanesulphonyl chloride employed in the following experi-ments was either purchased or prepared from methyl sulphate,this ester being converted into methyl thiocyanate by means ofaqueous potassium thiocyanate.Methanesulphonic acid was thenproduced by oxidising methyl thiocyanate with nitric acid, andfreed from water as completely as possible by repeated evaporation.Treatment with phosphorus pentachloride led to the formation ofa mixture of phosphoryl chloride and methanesulphonyl chloride,which was fractionated under the ordinary and also under reducedpressure. All the specimens of methanesulphonyl chloride employedcontained appreciable amounts of phosphorus compounds, whichFROM ALKYL- AND ARYL-SIJLPHONPI;-PARA-DIAMINES 6 1fortunately, did not interfere seriously with the following con-densation.Methanesulphonyl-p-nitroanaine, CH,*S'OZ*NH*C,H,*NO2.Ten grams of methanesulphonyl chloride were added to a warmtoluene solution of p-nitroaniline (10.5 grams) and triethylamine(10 grams); a heavy, oily layer separated, and rings of triethyl-amine hydrochloride were projected from the flask. After boilingfor fifteen minutes, the solvent was evaporated off, and the residueextracted with excess of aqueous sodium carbonate until only aslight amount of tar remained undissolved.The solution wasthoroughly cooled, and the crystallised p-nitroaniline separated ;the filtrate acidified with hydrochloric acid gave an almost colour-less precipitate of methanesulphonyl-p-nitroaniline, the yield beingabout 9 to 10 grams.Very little condensation occurs in the absence of triethylamine,and in this respect methanesulphonyl chloride differs considerablyfrom methionic chloride, which reacts energetically with p-nitro-aniline, even in the absence of any condensing agent.Methanesulphonyl-p-nitroaniline crystallises readily from dilutealcohol in pale yellow needles or transparent, amber-coloured prisms ;it melts a t 186O:0.1212 gave 13.9 C.C.N, a t 20° and 756 mm.C,H8O4NZS requires N = 12.96 per cent.This nitro-compound dissolves readily in aqueous sodium car-bonate or ammonia, and is slightly soluble in water; it is notreprecipitated from its alkaline solutions by acetic acid, but onlyby mineral acids.N=13*06.Methanesulpl~onyZ-p-phenylenylene&am&ne, CH,*S0,*NH*C,H4*NHz.The foregoing nitro-compound could not be reduced satisfactorilyby iron and dilute acetic acid, zinc and ammonia, aluminiumamalgam, stannous chloride, or ammonium sulphide.The bestresult was obtained by dissolving 2 grams of nitro-compound in20 C.C. of 50 per cent. alcohol, containing 0.5 gram of ammoniumchloride. On adding excess of zinc dust to the warm solution,reduction occurred, and was completed by boiling for a short time.The alcoholic filtrate was rapidly evaporated to dryness, and theresidue extracted with benzene. When crystallised from thissolvent, the base separated in colourless needles, melting a t 122O :0.1327 gave 18.1 C.C. N, a t 20° and 772 mm.0.1588 ,, 0-2036 BaSO,. S= 17.60.N=15*86.C7H,,0zNzS requires N = 15.05 ; S = 17.20 per cent62 MORGAN AND PICKARD : PRODUCTION OF DIAzOIMIDES.The hydrochloride of methanesulphonyl-p-phenylenediamine,which is readily soluble in water or alcohol, separates in colourlessleaflets, melting a t 223O:0.1192 gave 12.7 C.C.N, a t 21'5O and 761 mm.C,H;,O,N,S,HCl requires N = 12.53 per cent.The sulphate is somewhat less soluble in water, and is precipitatedby alcohol from its aqueous solution. The diazonium chlorideseparated in colourless plates on adding successively ethyl nitriteand dry ether to an alcoholic solution of the hydrochloride; itrapidly becomes brown and viscid on exposure to the atmosphere.The diazonium sulphate was more stable than the diazoniumchloride, and separated in colourless crystals on adding ethylnitrite aad ether successively to a solution of the sulphate in glacialacetic acid.These diazonium salts, when added to strong aqueous solutionsof sodium acetate, gave either a resinous product or an intenselyyellow solution, the result depending on the concentration of thesodium acetate.Only in two isolated cases was a, yellow, crystallineproduct obtained in this way. This compound decomposed violentlyon gently warming, whereas the resinous product burnt quietly.The former of these substances was evidently the diazoimide, aswas proved by coupling it with B-naphthol.The diazoimide was obtained in the solid condition by mixingcold aqueous solutions of methanesulphonyl-p-phenylenediaminehydrochloride and sodium nitrite, taking these salts in accuratelyweighed molecular proportions.The solution was rapidly filteredfour or five times, and when of a clear yellow colour was evaporateda t the ordinary temperature in a vacuum desiccator over phosphoricoxide and potassium hydroxide. An orangeyellow residue wasobtained, consisting of the diazoimide (decomposition point 150O)and sodium chloride in approximately molecular proportions. Themixture was ground up thoroughly, and the sodium chlorideestimated as sodium sulphate after heating with pure concentratedsulphuric acid. After making allowance for the proportion ofsodium chloride present, the following results were obtained :N=12*11.0.1765 gave 0.2668 CO, and 0.0646 H,O. C = 41-23 ; H = 4.06.0.1353C7H70,N,S requires C = 42.64 ; H = 3.65 ; N = 21.31 per cent.The diazotisation was now repeated, using silver nitrite insteadof sodium nitrite, the dry salt being thoroughly triturated withthe aqueous solution of methanesulphonyl-pphenylenediaminehydrochloride. After filtering off the silver chloride, the clearyellow solution contained only the methanesulphonyl-p-phenylene-diazoimide ; the substance appeared, however, to be less stable than,, 25.5 C.C. N, a t 20° and 772 mm. N=21*90THE ACTION OF HYDROGEN DIOXIDE ON THIOCARBAMIDES. 63in the presence of sodium chloride, and showed signs of losing someof its diazo-nitrogen. The final residue was shown to containdiazoimide by coupling with P-naphthol in pyridine solution. Abright red azo-P-napht-hol was produced, which melted a t 244-245*,and was identical with rnethanesulphonyl-p-ar&ohenzeneazo-P-naphthol, prepared by coupling methanesulphonyl-p-aminobenzene-diazoniurn chloride with alkaline &naphthol. In the latter pre-paration the azo-j?-naphthol was produced in the form of its solublealkali derivative, and was precipitated by dilute acetic acid. Thefree azo-j?-naphthol was almost insoluble in alcohol, but crystallisedreadily from glacial acetic acid in red, glossy, filamentous needles;it melted a t 244-246*, and dissolved in concentrated sulphuricacid to a deep red solution:0.1147 gave 12.3 C.C. N, at 19O and 758 mm. N=12*30.C,7H,,03N3S requires N = 12.31 per cent.We desire t o express our thanks to the Government Grant Com-mittee of the Royal Society and the Research Fund Committee ofthe Chemical Society for grants which have partly defrayed theexpenses of this investigation.ROYAL COLLEGE OF SCIENCE, LONDON.SOUTH KENSINGTON, S. W