None
Formation. — 1. By treating nitro-benzene with alcoholic potash (Mitscherlich, A. 12, 311 ; Schmidt a. Schultz, A. 207, 328), sodium-amalgam in presence of alcohol and acetic acid (Werigo, A. 135, 176 ; Alexejeff, Z. [2] 3, 33), iron (3 pts.) and acetic acid (1 pt.) (Noble, A. 98, 253), or with zinc-dust (Alexejeff, Bl. [2] 34, 684).— 2. By oxidising aniline with aqueous KMn04 (Glaser, A. 142, 364), red-hot PbO (Schichuzky, J. B. 6, 245), H,O2 (Leeds, C. N. 44, 210 ; B. 14, 1382) or bleaching powder (Schmitt, J. pr. [2] 18, 195).— 3. It is the chief product of the action of sodium on ^-bromo-aniline (Anschutz a. Schultz, B. 9, 1398; c/. Claus, B. 15, 315). Preparation. — 1. By heating nitro-benzene with a solution of sodium stannite prepared by dissolving the theoretical quantity of SnCl2 in an excess of aqueous NaOH (Witt, B. 18, 2912). — 2. 400 grins, of NaOH (98 p.c. powdered) are boiled with 2000 c.c. of ordinary alcohol till most has dissolved ; 500 g. of nitrobenzene are slowly added to the boiling solution, and the formation of azoxybenzene completed by 2 or 3 hours' cohobation. 200 grms. of zinc-dust are then slowly added and the boiling continued for a day with occasional shaking. The alcohol is distilled off on a salt bath, warm water added, the insoluble portion filtered off, washed, freed from Zn(OH)2 by HC1, and extracted with alco- hol ; the filtrate on cooling deposits the azo- benzene in splendid large plates ; good yield. Properties. — Trimetric plates (Jeremejeff). Crystallises with C6H6 from benzene. Its absorp- tion-spectrum has been described by Hartley (C. J. 51, 176). Reactions. — 1. Passed through a red-hot tube it yields benzene and diphenyl (Ferko, B. 20,664). 2. Chromic acid in acetic acid at 200° forms benzene-azoxy-benzene. — 3. Nitric acid forms Ph.N2.C6H4(N02) [1:4], Ph.N,.C<iH4(N02) [l:2j, [4:1] C8H4(N02).N2.C11H;(N02) [1:4], [1:3] C6H4(NO2).N2.C6H4(N02) [1:3], and a nitro- benzene - azo - di - nitro - benzene. — 4. Alcoholic ammonium sulphide reduces it to hydrazo- benzene (Hofmann, Pr. 12, 576). — 6. Hot cone. HC1, HBr, or HI reduces it to benzidine, other products being formed at the same time. — 6. Alcoholic S02 produces benzidine. — 7. With an ethereal solution of zinc ethyl it reacts form- ing ethane (1 vol.), ethylene (3 vols.), aud a 374 AZO- COMPOUNDS. product which, when treated with water, gives aniline. 80 g. of azo -benzene gives 70 g. of aniline. The reactions are probably : — (a) PhNJPh + 2ZnEt2 = 2NPhH(ZnEt) + 2GjH4 (6) PhN.]Ph-i-4ZnEt,= 2NPh(ZnEt)2 + 2C,H6 + 2C.,H4. And then, on adding water : (a1) NPhH(ZnEt) + H.,0 = NPhH, + EtH + ZnO (&') NPh(ZnEt)2 + 2H2O = NPhH., + 2EtH + 2ZnO (Frankland a. Louis, G. J. 37, 560).— 8. Alde- hyde at 200° forms a compound GogH^N-jOg [104°]. In presence of chloride of zinc, alde- hyde condenses with it to benzylidene-benzidine Ph.CH:N.C6H4.CliH4.N:CH.Ph (?) [239°] (Barzi- lovsky, J. B. 1885, 366).— 9. Bromine forms mono-bromo- derivatives, a di-bromo- derivative, [205°] (v. BKOMO-BENZENE-AZO-BBOMO-BENZENE), and a tetra-bromo- derivative, C,2HliBr4N2, [c. 320°] (Werigo, A. 165, 200). Combinations. — C12HION2,C6II8 [38°]. — (C12H10N2)23HC1 : unstable yellow crystals. — (Cl2H,0N2)23HBr : unstable red crystals, got by passing HBr into a solution of azobenzene in CS2. — C,2H10N2HBr3: crystals, formed by adding bromine to a solution of the preceding body in chloroform. — C,,HION2Br6 : red prisms, got by adding excess of bromine to a solution of ben- zene-azo-benzene in chloroform (Werigo, A. 165, 203). Benzene-azo-benzene sulphonic acid C6H5— N2— C6H4SO3H [1:4]. [127°]. From ben- zene-azo-benzene and fuming H,S04 (5 pts.) at 130° (Griess, A. 131, 89 ; 154, 2"08 ; Janovsky, M. 2, 221; 3, 237; B. 15, 2576). Orange-red plates (containing 3aq). 81. sol. alcohol and ether. Potash-fusion converts it into K.,SO, and benzene-azo-phenol. Ammonium sulphide followed by mineral acid converts it into di- amido-di-phenyl sulphonic acid. Nitric acid forms mono-, di-, and tri- nitro- derivatives (Janovsky, M. 3, 508). Salts.— KA'2aq.—BaA'2.—AgA'. Chloride C12H9N2S02C1. [82°]. Orange clumps (from ether). Amide C,.,H!IN.;S02NH2. Powder (Skanda- roff, Z. [2] 6, 643). Benzene-azo-benzene disulphonic acid C..H5— N2-CttH3(S03H)2 [1:2:4]. Formed, to- gether with s-m-, and s-p-, sulpho-benzene-azo- benzene sulphonic acids by heating benzene- azo-benzene (1 pt.) with pyrosulphuric acid (4 pts.) at 150° (Janovsky, M. 3, 237). Very deliquescent needles. Isomerides of this acid are described as sulpho-benzene-azo-benzeue sulphonic acid. Benzene-azo-benzoic acid C..H.,.N,.C8H4(COiH) [1:4]. Azo - benzene -p - carboxylic acid. Obtained by saponincation of its nitrile by boiling with KOH. Long glisten- ing brown prisms. Sol. alcohol, ether, and warm benzene. Salts.— A'K: very soluble brownish-yellow needles. — A'.;Ba : brownish-yel- low needles ; sol. alcohol, si. sol. water (Mentha a. Heumann, B. 19, 3023). Nitrile C(jH5.N2.C6H4(CN) [1:4]. p-Cyano- azo-benzene. [101°]. Formed by diazotising benzene-azo-aniline and allowing the solution of diazo-benzene-azo-benzene chloride to drop into a hot solution of CuSO4 and KCN. Brown needles. V. sol. ether, - benzene, and warm alcohol, insol. water. Sublimable (M. a. H.). Benzene-azo-benzoyl-acetic acid CdHi.N,.CH(CO.CttH,).CO,H. [141°]. Long yel- low needles. V. sol. alcohol, ether, and acetic acid. Its ethyl-ether is formed, together with benzene-azo-acetophenone, by adding a solution of diazobenzene chloride to an iced alkaline solution of benzoyl-acetic ether. By boiling with dilute NaOH it is converted into benzene- azo-acetophenone CdHvN2.CH2.CO.C6H5 (Bam- berger a. Caiman, B. 18, 2563). Benzene-azo-benzylidene-anilin e 0^5— N2— GJIt.N:CH.GaH.3.Benzylidcne-amido- azo-benzene. [125°]. Orange plates. Formed by the action of benzaldehyde on benzene-azo- aniline. By HC1 it is resolved into its con- stituents (Berju, B. 17, 1403). Benzene-azo-o-bromo-benzene C6H5 — N2— C0H4Br [1:2]. Bromo - azo - benzene. [87°]. Glistening plates (from alcohol). SI. sol. cold alcohol. By the action of bromine (1 mol.) upon a warm acetic acid solution of benzene- azo-benzene (1 mol.) a mixture of o, ra, and p, mono-bromo-benzene-azo-benzene is obtained ; they can be separated by their different solubili- ties in alcohol. By complete reduction they give aniline and o-, m-, or p-bromaniline. Benzene-azo-7u-bromo-benzene C6H5.Nii.C6H4Br [1:3]. [56°]. Yellowish -green pearly plates. V. sol. alcohol, ether and ace- tone. On nitration it gives orange needles of C,2H8Br(N02)N2 [123°] (Janovsky a. Erb, B. 20", 359). Benzene-azo-p-bromo-benzpne C6H5.N2.CsH4Br [1:4]. [82°]. Is the chief pro- duct of the bromination of benzene-azo-benzene in acetic acid. Orange yellow plates. Sub- limable. V. sol. alcohol, ether, and acetone. The corresponding hydrazo- compound forms white needles. On nitration it gives orange needles of <))2HljBr(NO,)N2 [108°] and also a di-nitro- derivative [190°] (Janovsky a. Erb, B. 19, 2155 ; 20, 357 ; M. 8, 49 ; v. also BKOMO- BENZENE-AZO-BROMO-BENZENE). Benzene-azo-tri-bromo-resorcin Ph_N2— C(jBrs(OH)2. [186°]. From benzene- azo resorcin and bromine (Typke, B. 10, 1578). Benzene-azo-p-chloro-benzene C6H5— N.2— C6H4C1 [1:4]. Chloro-azobenzcne. [89°]. Yellowish-brown plates. Sublimes in brown needles. Easily soluble in ether, benzene,, and hot alcohol, sparingly in cold alcohol. Preparation. — 100 grms. of benzene-azo-ani- line hydrochloride are suspended in 2 litres of water and 220 c.c. of cone. HC1, and diazotised by slow addition of a cone, solution of 20 grmg. sodium nitrite. After standing for some time the diazo-azo-benzene solution is filtered and slowly added to a boiling solution of 40 grms. Cu2Cl2 in 360 c.c. of cone. HC1, and boiled for some time ; the greyish-black pp. is treated with cone. HC1 and then with dilute NaOH to remove impurities, and extracted with hot al- cohol; the alcoholic solution after treatment with animal charcoal deposits the benzene>-azo- chloro-benzene on cooling in glistening brown plates ; the yield is 38 p.c. of the theoretical (Heumann a. Mentha, B. 19, 1686). Reactions. — When its alcoholic solution is allowed to stand in the cold with SnCl2 and 2 drops of H2S04 it is converted into a chloro- di-amido-diphenyl NH2.CIJH4.C6H3C1.NH2. The AZO- COMPOUNDS. 375 latter body is not formed, however, by heating the hydrazo- compound, previously prepared, with HC1, but benzene-azo-chloro-benzene, chloro-aniline, and aniline are formed instead. On nitration with fuming HN03 benzene-azo- chloro-benzene gives p-chloro-benzene-azo-j)- nitro-benzene CBH4Cl.N2.C(iH4(N02). By treat- ment with fuming sulphuric acid it is converted into ^7-chloro-benzene-azo-benzene jJ-sulphonic acid C6H4C1.N2.C6H4(SOSH) (Mentha a. Heu- mann, B. 19, 2970). Benzene-azo-o-cresol C^H,— N2-CBH3(CH3)(OH) [1:3:4]. [130°]. Glistening yellow plates. V. sol. alcohol, ether, chloroform, and benzene ; si. sol. hot, insol. cold, water. Dissolves in dilute alkalis with a yellowish red colour. Obtained by the action of diazobenzene chloride on an alkaline solution of o-cresoL It readily gives a dis-azo- compound when treated in alkaline solution with a further quantity of diazobenzene chloride. Acetyl derivative; [82°]; yellow tables, v. sol. alcohol, ether, and benzene. Benzoyl derivative: [1110]; small yellow needles, v. sol. ether, acetone, and hot alcohol (Liebennann a. Kostanecki, B. 17, 130 ; Nolting a. Kohn, B. 17, 363). Benzene-azo-TO-cresol CdH5— N2-C6H3(CH3)(OH) [1:2:4]. [109°]. Yellow needles. V. sol. alcohol, ether, chloro- form and benzene. With alkalis it forms yellowish-red salts. Obtained by the action of diazobenzene chloride on an alkaline solution of 7re-cresol. It readily combines with another mol. of a diazo- compound to form dis-azo- com- pounds (Nolting a. Kohn, B. 17, 366). Benzene-azo-p-cresol C6H5— N2— C6H3(CH3)(OH) [1:5:2]. [109°]. Orange yellow plates. Soluble in dilute alkalis. Dyes a canary yellow. Formed by the action of diazo-benzene chloride on an alkaline solution of p-cresol. It does not yield a dis-azo- compound. Acetyl derivative Ph — N2 — C7HB(OAc) : [68°] ; yellow needles, v. sol. alcohol, ether, chloroform, and acetone. Benzoyl derivative?}* — N2 — C7H6(OBz): [113°] ; yellow needles, sol. ether, benzene, and hot alcohol (Mazzara, G. 9, 425 ; Liebermann a. Kostanecki, B. 17, 130 ; Nolting a. Kohn, B. 17, 352). Benzene-azo-p-cresol-snlphonic acid CdH5-N2— C(JH2(CH3)(OH)(S03H) [1:5:2:3]. Small reddish brown tables or needles. Easily soluble in water, sparingly in alcohol. Formed by the action of diazobenzene chloride on an alkaline solution of p-cresol-sulphonic acid [1:4:2]. A'Na: soluble reddish brown plates, dyes wool an orange yellow (Nolting a. Kohn, U. 17, 357 ; cf. Stebbins, A. C. J. 1, 465 ; 2, 263). Benzene-azo-^-cumenol CdH4— N2— C8H(CH3)3OH [1:3:5:6:2] [94°]. Glistening brown prisms. In small quantities it can be distilled undecomposed. Insoluble in alkalis. Formed by combining diazo-benzene chloride with tf'-cumenol [70°J. On reduction it yields aniline and amido-tj'-cumenol [167°] (Liebermann a. Kostanecki, B. 17, 886). Benzene - azo - di - ethyl - amido - benz oic acid C.Hj— N2— CsH;1(NEt2)C02H[l:4:2]. [125°]. From diazo-benzene nitrate and di-ethyl-?;i-amido- bcnzoic acid. Bed crystals with violet lustre (from alcohol). Insol. water, si. sol. alcohol and ether. Salts: BaA'2.— AgA' (Griess, B. 10, 526). Benzene-azo-ethyl-(£)-naphthyl-amine C6HS— N2— C10H6.NHEt. [103°]. Bed needles. Soluble in alcohol &c. with an orange-red colour, insol. water. It forms bluish-violet salts with acids. Formed by heating ethyl-(j8)-naphthyl- nitrosamine with an acetic acid solution of aniline at 100°. Also produced by combining diazo-benzene with ethyl-(j8)-naphthylamine. Nitrosamine C6H5.N2.C10H,.NEt(NO) : [97°] ; red crystals (Henriques, B. 17, 2069). Benzene-azo-ethyl-phenylene-diamine C6Hs.N2.C8Ha(NH,)NHEt. Ethyl - chrysoidine. Dyes a redder shade than ordinary chrysoidine. Formed by combining ethyl-w-phenylene- diamine with diazo-benzene.— B"HC1: reddish- brown needles with violet-blue reflection, soluble in water and alcohol with an orange colour. — B"2H.JCLJPtCl4 ; insoluble red pp. (Nolting a. Strieker, B. 19, 547). Benzene-azo-indoxyl XC6H.— C(OH) C8HS— N2— N< || (?) \ CH [236°]. Bed needles or thick orange prisms. Sol. alcohol and alkalis, v. si. sol. water. Formed by the action of diazo-benzene chloride on indoxyl (Baeyer, B. 16, 2190). Benzene-azo-methane C,.H5 — N2 — CH3. Azo- phenyl-methyl. (c. 150°). Yellow oil of pecu- liar odour. Very volatile, and readily distils with steam. Formed by oxidation of s-phenyl- methyl-hydrazine C8HS.NH.NH.CH, with HgO (Tafel, B. 18, 1742). Benzene-azo-methazonic acid Ph— N?- C2H3N2OS. [164°]. From diazo-ben- zene nitrate and an aqueous solution of sodium methazonate (Kimich, B. 10, 141). Orange needles (from alcohol) ; insol. water. — Na.jA"2aq. — BaA"aq. Benzene-azo-di-methyl-amido-'benzoic acid Ph— N2— CBH3(NMe.i)C02H [1:4:2]. From diazo- benzene nitrate and di-methyl-m-amido-benzoio acid (Griess, B. 10, 527). Orange nodules. Benzene-azo-methyl-aniline C8Hj — N2 — C8H4.NHMe. Methyl-amido-azo-ben- zene. [180°]. Bed needles. Sol. alcohol. Formed by heating benzene - azo - aniline with Mel. — B'HCl: violet needles. Acetyl derivative CljHvN2.C(iH4.NMeAc : [139°]; yellow silky needles (Berju,.B. 17,1401). Benzene -azo-di-me thy 1-aniline C8Hi.N2.C8H4.NMe2. Di-melhyl-amido-azo-ben- zene. [115°]. Yellow plates. Preparation. — 1. A solution of 74 pts. of NaN02 (100 p.c.) and 40 pts. of NaOH in 540 pts. of water is slowly added to a cooled solution of 100 pts. of aniline, 130 pts of dimethylaniline, and 230 pts. of HC1 in 360 pts. of water (Griess, B. 10, 525 : Mohlau, B. 17, 1490).— 2. By heat- ing benzene-azo-aniline with Mel (Berju, B. 17, 1402 ; C. C. 1884, 871). Methylo -iodide B'MeL [174°]. Plates. Benzene-azo-methyl-ketole CtfHs— N2— C^N. [116°]. Yellow needles. Formed by the action of diazo-benzene-chlorido upon methyl-ketole hi aqueous alcoholic solution in presence of sodium acetate (Fischer, B. 19, 2090). 370 AZO- COMPOUNDS. Benzene-azo-methyl-phenylene-diamine CLHi.NrQiH^NH4)NHMe. MetJnjl-chnjsoUinc. Minute orange prisms. Dyes a somewhat redder shade than ordinary chrysoidine. Formed by combining diazobenzene with methyl-m-phenyl- ene diamine (Nolting a. Strieker, B. 19, 549). Benzene-azo-(a)-naphthol C6H5— N2— C10H6.OH. (a)-Naphtlioquinone- plienyl-hydrazidc. [206°]. Small needles with blue reflection (from alcohol) or flat needles or plates (from benzene). Formation. — 1. By combining (a)-naphthol with diazobenzene. — 2. By the action of phenyl- hydrazine hydrochloride upon (a)-napthoqui- none suspended in acetic acid. Reactions. — Dissolves both in acids and alkalis. Bromine forms two bromo- derivatives [185°], and [196°] (Margary, G. 14, 271). Salts. — A'K : crystalline pp. The hydro- chloride, hydrobromide, and sulphate form bluish or greenish glistening needles, sparingly soluble in water, alcohol, and acetic acid (Typke, B. 10, 1580). Methyl ether A'Me: [83°]; brown crystals. Ethyl ether A'Et : [100°]; long needles. Acetyl derivative C1(iH,,N2(OAc) [128°] ; small brownish-red needles (Liebermann, B. 16, 2858 ; Zincke a. Bindewald, B. 17, 3026). Benzene-o-azo-(a)-naphthol Oa [1:2]. (?) [138°]. (0)-Naphtho- \N,H.C6H5j3 quinone-phenyl-hydrazide. Formed by the action of phenylhydrazine hydrochloride upon (&)- naphthoquinone. Long red needles ; sol. hot alcohol and hot acetic acid. It does not combine with acids or bases. By SnCl2 it is reduced to (/3)-amido-(o)-naphthol. By treatment in hot acetic acid solution with HN03 it gives di-nitro- (ot)-naphthol. By the action of alkaline reducing agents it is at once converted into (£)-amido- (a)-naphthol; no intermediate product could be detected (Zincke a. Bindewald, B. 17, 3030; Zincke a. Kathgen, B. 19, 2482). Bromo- derivative C16H10N2Br20 ; [215°-219°] : slender red needles. Benzene-azo-(/3)-naphthol C16HUN20 i.e. C6HS.N2.C10HB.OH or C10H, xv [1:2]. [134°]. Formation. — By the action of a diazobenssene salt on an alkaline solution of j8-naphthol. It is not formed by the action of diazobenzene hydrate on finely divided (jS)-naphthol (difference from (o)-naphthol) (Liebermann, B. 16, 2858). Properties. — Golden plates or long metallic glistening needles. Soluble in ether, benzene, ligroine and CS2. Dissolves in H.,SO4 with a magenta-red colour. Is insoluble in caustic alkalis. It has a slightly basic character, dissolving in HC1 with a red colour, and form- ing an unstable hydrochloride crystallising in needles. By SnCl2 it is reduced to (a)-amido- (/3)-naphthol and aniline. The same reduction products are also formed at once by treatment with alkaline reducing agents (e.g. zinc-dust and NaOH, ammonium sulphide, &c.) ; no inter- mediate product was detected. When treated in hot acetic acid solution'with HN03 it gives di-nitro-((8)-naphthol (Zincke a. Eathgen, B. 19, 2482). Bromo- derivative C,,HnBrN.20: [168°]. Brownish-red needles (Zincke a. Bindewald, B. 17, 3031). Benzene-azo-(a)-naphthol snlphonic acid C.HS— N2— C10H.(S03H)(OH). From sodium (a)- naphthol sulphonate, aniline nitrate, and KN(X (Hofmann, B. 10, 1378). Slender brown needles (from alcohol mixed with HClAq). Dyes orange. — AgA'.— BaA'2. Benzene-azo-(/3)-naphthol sulphonic acid C.jH.j— N2— C^H^HSO^OH. Brown needles with yellowish-green reflex. Difficultly soluble in water and alcohol. Prepared by the action of an alkaline solution of (]8)-naphthol-sulphonic acid on diazobenzene nitrate or chloride. — A'2Ba. Yellowish red microscopic leaflets. Slightly soluble in water (Griess, B. 11, 2197). Its absorption-spectrum has been examined by Hartley (C. J. 51, 196). Benzene-azo (#)-naphthol disulphonic acid C6H5— N2— C10H4(S03H),(OH). From sodium (£)- naphthol disulphonate and diazo-benzene nitrate. Sol. water. Barium salt is si. sol. water (Stebbins, jun., A. C. J. 2, 236). Benzene-azo-(a)-naphthylamine CBH5 — N2— C10HBNH2. Prepared by the action of diazobenzene sulphate on (a)-naphthyl- amine (Griess, T. 1864, iii. 679 ; Weselsky a. Benedikt, B. 12, 228).— B',H,S044aq: micro- scopic needles ; difficultly soluble in water. B e n zene-az o - (ft) -napb. thy lamine /NH CA-Ns-C.pH.NH, or C10H/ 1 \N2H.CaH5. Benzene-hydrazimido-naphtJialene. [104°]. Bed trimetric tables or long fine red needles. Easily soluble in alcohol and acetic acid, insoluble in water. Dissolves in strong BL2S04 with a blue colour. Its salts exist only in presence of a large excess of acid. Formed by combination of diazobenzene with (/3)-naphthylamine. By boiling with 20 p.o. aqueous H,S04 it is slowly decom- posed into (j8)-naphthylamine, phenol, and nitrogen. On reduction it gives aniline and (1, 2)-naphthylene diamine. On oxidation it gives benzene-azimido-naphthalene (q.v.). Acetyl derivative C16H12AcN3. [153°]. Small red needles, easily soluble in alcohol, in- soluble in water. Benzoyl derivative C^H^EzNa: [163°], red crystals (Lawson, B. 18, 796). Benzene-o-azo-nitro-benzene C6H5— N2— C^H^NOJ [1:2]. Nitro-azobenzene. [123°]. Formed by nitration of benzene-azo-ben- zene in acetic acid at 100°. Orange-yellow minute needles. V. sol. alcohol. Alcoholic NaOH gives a beautiful emerald-green coloura- tion ; by long boiling or by treatment with sodium- amalgam it is further reduced to a compound C24H19N60. Tin and HC1 or ammonium sulphido first reduce it to benzene-o-azo-aniline and then to aniline and o-phenylene-diamine. By bro- mination in acetic acid it yields bromo-nitro- benzene [123°] or [132°] (Janovsky a. Erb, B. 19 .2157 ; 20, 360 ; M. 8, 56). Benzene-p-azo-nitro-benzene C6H5.N2.C8H4.NO2 [1:4]. [137°]. Small yellow needles (from alcohol). Formed by nitration of benzene-azo-benzene. By NH4HS it is reduced AZO- COMPOUNDS. 377 to ordinary benzene-azo-aniline. Alcoholic NH4HS produces red crystals of an intermediate C6H6.N2.C8H4.NOH nitrolic acid | (?) [134°], C8H5.N2.C8H,.NOH which forms a blue solution in NaOHAq. K3FeCy6 reoxidises it to benzeiie-azo-^-nitro- benzene. By complete reduction it yields aniline and 2>-phenylene-diamine (Laurent a. Gerhardt, .4.75,73; Janovsky, J3. 18, 1133; M. 6, 164, 455). Benzene-azo-tri-nitro-benzene CtiH5— N2— C6H,(N02)3. [142°]. By action of HgO on an alcoholic solution of the correspond- ing hydrazo- compound (E. Fischer, A. 190, 133). Slender red prisms (from alcohol). Benzene-azo-nitro-iso-butane C^Hj— N2 — CH(N02)Pr. From diazobenzene ni- trate and potassium nitro-iso-butane (Ziiblin, B. 10, 2088). Oil. Forms an orange solution in alkalis. Benzeue-azo-nitro-ethane C3Hj,N302 i.e. CJEs— N2— CH(N02).CH3. [137°]. From diazo- benzene nitrate and sodium nitroethane (V. Meyer a. Ambuhl, B. 8, 751, 1073). Rectangular orange crystals ; v. sol. alcohol and ether, insol. cold water, sol. aqueous alkalis forming a blood- red solution. Dyes silk yellow. Cone. ELS04 forms a violet solution. It crystallises unaltered from aqueous NHS (Barbieri, B. 9, 386) but such a solution gives pps. with metallic salts. Salt s.— CSH7K,NSO., 4aq. — C8H7Na.,N302 7aq. — C8H7ZnN302 3aq.— C8H7PbN302PbO 2£aq. Benzene-az j-nitro-methane CSH5— N2— CH...NO.J. [153°]. From diazoben- zene nitrate and sodium nitromethane in very dilute solution (Friese, B. 8, 1078). Slender red needles (from alcohol). Cone. H2S04 gives a purple solution. Decomposed by HClAq only after long boiling. Benzene-azo-tri-nitro-phenol C6HS— N2— C(fH(NO2)3OH. Long brown prisms. Insol. cold, si. sol. hot, water ; v. sol. alcohol. Explodes at 70°. Dyes silk and wool orange- yellow. Prepared by the action of a salt of diazobenzene on an alcoholic solution of picric acid (Stebbins, jun., A. C. J. 1, 465 ; 2, 236 ; C.N. 41, 117; B. 13,43). Benzene-azo-nitro-propane C6H?— N2-CH(N02).CH2,CH3. [99°]. From po- tassium nitropropane and diazobenzene nitrate (V. Meyer, B. 9, 386). Orange needles ; sol. alkalis. Benzene-azo-iso-nitro-propane C6H4— N2— C(NO2) (CH3)2. From aqueous diazo- benzene nitrate and potassium nitro-isopropane. Oil; insol. alkalis (V. Meyer a. Ambuhl, JJ. 8, 1076). Benzene-azo-o-oxy-benzoic-acid C»H&— N2— C8H3(OH).CO,H. From diazobenzene nitrate and an alkaline solution of salicylic acid (Stebbins, jun., A. C. J. 1, 465; B. 13, 715; C. N. 41, 117). Orange-red needles ; insol. water, v. sol. alcohol or ether. Dyes wool orange. Benzene-azo-di-oxy-naphthalene C.H4-N8-0IOHS(OH)2 or C10H5(OH) Oxy - (a) - naphthoquinone phenyl - hydrazide. [230°]. Formed by the action of phenyl- hydrazine on oxy-naphthoquinone in aqueous- alcoholic solution. Yellowish-red glistening needles. V. sol. ether, hot alcohol, and hot acetic acid. Salts. — The alkali salts form slender orange needles, sol. alcohol. — A'-jBa lOaq : yellowish- brown plates or long red needles. — A'^Ca 4aq : slender orange needles. — A'Ag : reddish-brown amorphous pp. Acetyl derivative: [179°]; red needles. Methyl ether A'Me: [175°]; red needles. Ethyl ether A'Et: [173°]; yellowish-red needles, v. sol. hot alcohol and hot acetic acid. Bromo-derivative C18HnBr02N2: [198°] ; large red needles, si. sol. alcohol (Zincke a. Thelen, B. 17, 180.)). Benzene-azo-pb.enolC.jHs— N2— C6H4.OH[1:4]. Oxy-azo-benzene. [154°]. Formation. — 1. A product of the action of BaC03 on diazobenzene nitrate in the cold (Griess, A. 137, 84). — 2. From benzene-azo-ben- zene sulphonic acid by potash fusion (Griess, A. 154, 211). — 3. From diazo-benzene nitrate and CdH5OK (Kekule a. Heidegh, Z. [2] 6, 384).— 4. By the action of ^-nitroso-phenol (20 pts.) on aniline acetate (60 pts.) (Kimich, B. 8, 1499).— 5. By gently warming benzene-azoxy-benzene, C6H5— N2O— CtiH5, with H2S04 (Wallach, B. 13, 525 ; 14, 2617). Properties. — Purple pyramidal plates. Insol. cold water, sol. alkalis ; v. sol. alcohol. Bro- mine in acetic acid gives a compound [139°]. Salt.— AgA'. Acetyl derivative. — Ph.N2.CBH4OAc. [85°]. (above 360°). Golden scales. Methyl ether. — Ph.N2.C8H4OMe [54°]. Yellow scales. Benzene-azo-phenol sulphonic acid C8H3— N2— C8H3(OH)(S03H) [1:4:3]. From diazo- benzene nitrate and an alkaline solution of phenol o-sulphonic acid (Griess, B. 11, 2194). Bed needles or tables ; sol. water and alcohol. — KA'. Benzene-azo-phenol sulphonic acid C12H8N2(OH)(S03H). From benzene-azo-phenol and fuming H2SO4 (Tschirvinsky, B. 6, 560).— BaA'22aq.— CuA'26aq.— MgA'26aq.— KA'. Benzene-azo-phenol di-sufphonic acid C12H;N2(OH)(S03H)2. From azoxybenzene (1 pt.) and fuming BLjS04 (10 pts.) by heating for 3 hours at 150° (Limpricht a. Wilsing, A. 215, 232 ; B. 15, 1297). Orange needles, v. e. sol. water, v. sol. dilute acids. Salts.— K2A" 2aq: red needles, si. sol. cold water ; not attacked by Br. — BaA" aq : orange crystalline pp. — Ag2A" : red crystalline pp. Benzene-azo-phenol tetra-sulphonic acid *C12HiN2(OH)(S03H)4. From azoxybenzeno and fuming H2S04 (L. a. W.). Will not crystal- lise. Salts.— CI2HsN2(OK)(SOsK)47iaq ; long yellow needles. Gives with bromine-water a pp. of tri-bromo-phenol [92°]. — Ba^A1* 7aq : orange crystalline pp. Other benzene-azo-phenol sulphonic acids are described as Oxy-benzene-xzo-benzene sulphonic acids, and sulpho-benzene-Lzo-phenol sulphonic acids. Benzene-azo-diphenylamine C8H5— N2-C8H4.NH.C8H5. [82 3] (0. N. Witt, C. J. 85, 185 ; B. 12, 259). A solution of di- phenylamine (17 g.) in alcohol (100 c.c.) is added to a solution of diazo-benzene chloride (14 g.) in alcohol (50 g.). The brown mixture is cooled with ice, and alcoholic NMe, (used instead of NH3 because NMe,HCl is soluble in alcohol) ia 378 AZO- COMPOUNDS. added from time to time to neutralise the liquid. The oil which separates is purified by a lengthy process, and finally crystallised from benzoline. Properties, — Golden leaflets or needles. Sol. benzene, alcohol, and ether. HC1 turns its alcoholic solution violet; steel -grey crystals of the hydrochloride separating. The base forms a green solution with H^SO4 turned, by adding water, into indigo, violet, and finally red. With amyl nitrite and acetic acid it forms a nitrosamine, Ph.N(NO).CJH4N..>Ph, [120°], forming orange needles, sparingly soluble in alcohol and acetic acid, readily in benzene. Benzene-azo-ra-phenylene diamine CDHS— N2— C,H3(NH,).2 [1:2:4]. Chrysoidine. [117-5°] (W.) ; [110°] (H.). From diazobenzene salts and m-phenylene diamine (Witt, B. 10, 350, 654 ; Hofmann, B. 10, 213, 388 ; Griess, B. 10, 390). Slender yellow needles (from water) ; si. sol. water, v. sol. alcohol. Reduced by am- monium sulphide at 150° to aniline and (1,2, 4)- tri-amido-benzene. The absorption-spectrum has been examined by Hartley (C. J. 51, 178). — B"HC1 : black octahedra or small red silky crystals; its aqueous solution is orange, but turned red by HC1— B"2H,PtCl6.— B"HNOS. Di-acetyl derivative Ph— N2— CtiH3(NHAc)2 [251°]. Eenzene-azo-7«-phenylene-diamine sulphonic acid C6H5— N2— C6H3(NH,),(S03H). Chrysoidine sulpJwnic acid. Glistening spangles or needles. SI. sol. water and alcohol. Prepared by the action of diazobenzene-chloride on a salt of w-phenylene-diamine sulphonic acid. A'Na : soluble golden needles— A'jBa : orange needles (Buhemann, B. 14, 2655). By the sulphonation of chrysoiidine an isomeric acid is formed (v. Di-amido-benzene-azo-benzene sulphonic acid). B enz ene-azo - di - phenyl - methyl - pyrrol-car - boxylic acid C24H1902N3 i.e. H02C.C:CMex ^KC^N^C^. [195°]. Obtained HaCPh' by saponification of its ethyl ether, which is formed from an acetic acid solution of aceto- phenone-aceto-acetic ether (1 mol.) and benzene- p-azo-aniline (1 mol.) on standing for two days. Large red crystals. V. sol. alcohol, ether, and benzene; si. sol. ligroin and acetic acid; insol. water, and cone, acids. Gives Laubenheimer's reaction. Ethyl ether EtA': [123°]; splendid red crystals ; v. sol. benzene and ligroin, si. sol. alcohol, ether, and acetic acid (Paal a. Schneider, B. 19, 3162). Benzene-azo-phenyl-(£)-naphthyl-ainine , i.e. CSH4-N2-C10H6NHC6HS or N.C6H5 2tt5 Benzene • phenyl - hydrazimido - naphthalene. [142°]. Obtained by combining diazo-benzene chloride with phenyl-(0)-naphthyl-amine in alcoholic solution. It is also formed by the action of an acetic acid solution of aniline upon phenyl-(0)-naphthyl-nitrosamine. Small red glistening needles. Reactions.— 1. By heating with cone. HC1 it /N\ yields naphthophenazine C^ILX I /C10H6 and aniline.— 2. Bromine acting on the hot acetic acid solution forms tetra-bromo-phenyl-(jS)- naphthylamine with evolution of nitrogen. — 3. It is reduced by SnCLj to aniline and phenyl- o-naphthylene diamine C10Hd(NH2)NHC?H5.— 4. By oxidation with K,Cr20, in acetic acid solu- tion the chromate of a powerful ammonium- base C22H16N3OH is formed ; the latter possibly. has the constitution C10HX |\ \N.N.C6HS v. Naphthalene di-phenyl-kZAmiom (Henriques, B. 17, 2671 : Zincke a. Lawson, B. 20, 1167). Benzene-azo-di-phenyl-thio-urea C^HS— N2— CdH,.NH.CS.NHPh. [179°]. Plates. Formed by combination of phenyl-mustard-oil with benzene-azo-aniline (Berju, B. 17, 1405). Benzene-azo-pyrogallol CdH5— N2— CdH,(OH)3. Prepared by adding an aqueous solution of diazobenzene nitrate to an alkaline solution of pyrogallol (Stebbins, jun., A. C. J. 1, 465 ; 2, 236 ; B. 13, 44 ; C. N. 41, 117). Bed needles (from acetic acid). Insol. water, sol. alcohol. Its alcoholic solution dyes silk and wool orange. Benzene-p-azo-resorcin C6H5-N2-C6H3(OH)2 [1:2:4]. [161°] or [170°]. From diazobenzene nitrate and resorcin (Typke, B. 10, 1577 ; Wallach, B. 15, 2819 ; B. Meyer, B. 16, 1329). Formed also by gently warming diazobenzene anilide with resorcin, aniline being eliminated (Heumann a. Oeconomides, B. 20, 905). Slender orange needles [170°] or short red needles [161°], insol. water, sol. aqueous alkalis, v. e. sol. alcohol. Acetyl derivative [102°]. Mono -ethyl ether [87°]. Scarlet needles. Diethyl ether [70°]. Yellowish -red needles. Benzene-o-azo-resorcin CtiH5.N2.C(iH3(OH)2 [1:2:6]. Formed in small quantity (about 5 p.c.) in the preparation of the p-isomeride. Mono-ethyl ether C(jH5.N2.C6H3(OH)(OEt) [150°]. Long fine scarlet needles ; v. e. sol. alco- hol and ether, insol. water ; dissolves in aqueous alkalis with a brownish -red colour. Di-ethyl-etherG6H.^2.CeH3(OEt)2: [90°]. Large red glistening tables ; v. sol. ether, hot alcohol and acetic acid, insol. water (Pukall, B. 20, 1145). Benzene-azo-thymol CtH..— N2— CdH2MePr(OH) [1:2:5:4] [85°-90°]. From diazobenzene chloride, and an alkaline solution of thymol (Mazzara, G. 15, 52, 228). Beddish-yellow needles. Beduction followed by oxidation gives thymoquinone. Benzene-azo-thymol-sulphonic acid C6H5— N2— CBH(CH3)(C3H7)(HS03)OH. [216°]. Small yellow prisms. Yellow colouring matter. Prepared by the action of diazobenzene chloride on a salt of thymol-sulphonic acid. Salts. — A'Na : small yellow crystals. — A' JBa : fine hair- like needles (Stebbins, B. 14, 2793). Benzene-p-azo'toluene CSHS— N2 — (^H^GHs) [63° corr.]. Formed by diazotising amido-ben- zene-^-azo-toluene C6H4(CH3)— N2— C6H4(NH.J dissolved in alcohol and boiling the solution (Schultz, B. 17, 466). Orange-red plates; v. sol. alcohol. Volatile with steam. By treatment with alcoholic SnCl2 and H2S04 it is converted into a base melting at [116°]. AZO- COMPOUNDS. 379 Benzene-azo-7>j-tolylene diamine C0H4— N2 - C0H,Me(NH.,)2. Yellow needles. Easily soluble in alcohol, sparingly in water. Prepared by the action of diazobenzene chloride on (1, 2, 4) tolylene- diamine, [99°]. — B'HCl : orange red needles (Stebbins, jun., A. C. J. 1, 465 ; B. 13, 717 ; C. N. 41, 117). Benzene - azo - xylenol CtiHs.N.!.C<iH.2Me? OH [1:3:5:2]. [175°]. Formed by combining diazo- benzene chloride with m-xylenol CdH,Me2(OH) [1:3:4] (Grevingk, B. 19, 148). Slender brownish- red needles. V. sol. alcohol, ether, and benzene, insol. water. On reduction it yields aniline and o-amido-w-xylenol C,H;iMe;,(NH,)(OH) [5:3:2:1]. Bromo-amido-benzeue-azo-jO-bromo-aniline Diacetyl derivative [2:5:1] NHAc.C^HjBr— N2— C6H3Br.NHAc [1:5:2] [282°]. Formed by warming acetyl-bromo-nitro- aniline C6H3(NHAc)Br(N02) [2:5:1] with zinc and cone. NH.,Aq (C. H. Matthiessen a. Mixter, Am. 8, 347). Pale red substance. p - Bromo - benzene - azo - benzene -p-sulphonic acid [4:1] C6H4Br — N2 — CBH4(S03H) [1:4]. Formed bysulphonation of benzene-jj-azo-bromo- benzene or by bromination of benzene-azo-ben- zene-p-sulphonic acid. Flat needles (containing 3aq). Salts. — KA': rhombic tables. — NaA' : yellow silky needles, si. sol. water (Janovsky, M. 5, 162 ; B. 20, 358 ; M. 8, 53). m- Bromo - benzene-azo-benzene -|)-sulphonic acid [3:1] C^H.Br— N2— C^H^SOsH) [1:4]. Formed by sulphonationof benzene-m-azo-bromo- benzene with fuming sulphuric acid. Glistening golden plates (containing 1| aq). Salts. — KA': yellow pearly pp. of micro- scopic needles. — NaA': pp. v. si. sol. water (Janovsky a. Erb, B. 20, 359). o-Bromo-benzene-o-azo-bromo-benzene [2:1] CfcH4Br-N2— C.H.Br [1:2]. [185°]. A product of the bromination of benzene-azo- benzene in HOAc (Janovsky, M. 8, 50 ; B. 20, 337). Golden plates, si. sol. alcohol. On nitra- tion it gives a tri-nitro- derivative [135°]. £>-Bromo-benzene-p-azo-bromo-benzene [4:1] C8H4Br— N2— C6H4Br [1:4]. [205°]. Formed by bromination of benzene-azo-benzene (Werigo, A. 135, 178 ; 165, 189). Formed also by reduc- tion of ^>-bromo-nitro-benzene with zinc-dust and alcoholic KOH (Schultz, B. 17, 465). Yellow needles. By alcoholic SnCl2 and H2S04 it is converted into a di - bromo - di - amido- diphenyl. Fuming H2S04 forms a sulphonic acid C,,,H7Br2N2S03H 3aq (W.). ro-Bromo-benzene-m-azo-bromo-benzene [3:1] C6H4Br— N2-C6H1Br [1:3]. [126°]. From the corresponding hydrazo- compound by Fe^Clg (Gabriel, B. 9, 1407). Tribromo-benzene-azo-dimethyl-aniline C6H,,Br3— N2— CsH4(NMe2). [161°]. Formed by adding an alcoholic solution of dime thy laniline (2 mol.) to CgHjBrjNj.NO, (1 mol.). Crystalline pp. Bed plates (from glacial acetic acid). Insol. water, hardly soluble in alcohol. It combines with cone. HC1 (Silberstein, J. pr. [2] 27, 124). Tribromo - benzene - azo - methyl - diphenyl- amine C0HJBr3— N2— CgH,NPhMe. [138°]. From C6H,,Br3N2N03 and NPh2Me in alcohol. Small brownish-red plates (from glacial acetic acid). Insol. water, si. sol. alcohol. Does not combine with HC1 (Silberstein, J.pr. [2] 27, 125). Bromo-benzen3-azo-(a)-naphthol [4:1] CtfH,Br— N2— C10H.OH [1:4]. [196°]. From ^7-diazo-bromo-benzene and (o)-naphthol, or by bromination of benzene-azo- (a) -naphthol (Mazzara, O. 14, 271). p- Bromo - benzene - azo - (6) - naphthol [4:1] 06H4Br— N2— C.oH.OH [1:2]. [161°]. From jp-diazo-bromo-benzene and (0) -naphthol, or from benzene-azo-(£)-naphthol and bromine (Mazzara, O. 13, 438). Orange needles. j?-Bromo-benzene-p-azo-nitro-benzene [4:1] C^Br-N.-C.H.fNO.) [1:4]. [108*]. Formed by nitration of benzene-p-azo-bromo- benzene. Yellow needles. V. sol. alcohol (Janovsky a. Erb, B. 20, 358). Bromo-benzene-azo-di-nitro-benzene (?) [4:1] C6H4Br— N2— C6H,(N02)2 [1:2:4] (?). [190°]. Formed by nitrating benzene-jj-azo-bromo-ben- zene (Janovsky, M. 8, 52). ^-Bromo-benzene-azo-nitro-ethane [4:1] C8H4Br-N2— CH(N02).CH3. [o. 137°]. From _p-diazo-bromo-benzene nitrate and potas- sium nitro-ethane (Wald, B. 9, 393). Brick-red crystals (from dilute alcohol) ; sol. ether, glacial HOAc, and chloroform. S a 1 1.— CgH7KN3O2Br. Di-bromo - di - imido-di -hydro- anthracene -azo - di-bromo-di-imido-di-hydro-anthracene C^HjB^N,, or NH NH C.H^^C^r^-N.-Br.HC^^H, (?) NH NH [233°]. Prepared by heating dibromo - nitro- anthraquinone with alcoholic Nil., (Claus a. Diernfellner, B. 14, 1335). Bed needles. Sub- limable. SI. sol. alcohol and ether, insol. water or aqueous acids and alkalis. Bromo - di - oxy - benzene - azo - bromo - hydroquinone. Tetra-methyl derivative CdH.3r(OMe)2— N2— C6H.^r(OMe)2. [220°]. Formed by bromination of the tetra-methyl derivative of di-oxy-benzene-azo-hydroquinone (Baessler, B. 17, 2125). Bed crystalline solid, v. sol. benzene, chloroform, and CS2, v. si. sol. alcohol, insol. water. Brorao-sulplio-benzcne-azo-benzene sulpho- nic acid [6:3:l]C6H.1Br(S03H)—Nt—C<jH3Br[S03H) [1:6:3]. Formed by oxidation of a neutral aqueous solution of bromo-amido-benzene sulphonic acid CuH3Br(NH,)(S03H) [4:3:1] with KMnO.. Salts. — KA"2aq: glistening red tables (Lim- pricht, B. 18, 1422). Di-bromo -sulpho -benzene-azo-di-bromo-ben- zene sulphonic acid [2:6:4:l]C6H2Br2(S03H).N2.C6HJBr2S03H[l:2:6:4]. From potassic di - bromo - o - amido - benzene sulphonate and KMn04 (Bodatz, A. 215, 222). Bed plates (containing 2aq). V. sol. water or alcohol. Beduced by SnCl2 to the original C8H2(NH2)Br2S03H. Salts. — K,A"2aq. _ BaA" 3aq.— CaA" 4aq.— PbA". Chloride.— [258°-262°]. Brown plates. Amide. — Violet silky needles. Di - bromo - sulpho - benzene - azo - di - bromo- benzene sulphonic acid [4:6:3:l]C6H2Br2(S03H).N2.C6H.^r2S03H[l:4:6:3]. From potassic di-bromo-amido-benzene sulpho- nate and KMn04 (Bodatz, A. 215, 216). Slender red needles, containing li aq (from water). V. sol. water, v. e. sol. alcohol. Bcduccd by SnCl2 380 AZO- COMPOUNDS. to the original C<jH.,(NH,)Br,.SOJH. Salts.— K.A" 3aq. — BaA" aq.— CaA" 4aq. - Pb A" 2 £aq. Chloride.— [233°]. Brick-red needles. Amide. — Microscopic orange needles (from alcohol). Does not melt. An acid isomeric with the above may be got by the action of KMn04 on the tetra-bromo- Lydrazo-benzene di-sulphonic acid of Jordan, A. 202, 361. Tri - bromo - sulpho - benzene - azo-tri - bromo- benzene sulphonic acid [2:4:6:3:1] C,iHBr3(S03H)— N2- C8HBr3(S03H) [1:2:4:6:3]. From potassic tri-bromo-m-amido-benzoate by KMn04 (Rodatz, A. 215, 225). Flat orange needles. Reduced by SnCl2 to the original " 3aq.— BaA"2aq.— CaA" 7aq.— PbA"4aq. Chloride.— [222J-224°]. Dark violet tables. Amide. — Brown crystals that do not melt. Di-br omo - sulpho - benzene - azo- (3) - naphthol C0ELBr2(S03H)— N2— C10HdOH (Stebbins, G. N. 42, 44 ; A. C. J. 2, 236). From diazo-dibromo- benzene sulphonic acid and an alkaline solution of (0) -naphthol. Di-bromo - sulpho -benzene- azo-di- oxy-naph- thalene C^Br^SO^)— N2— C1?H6(OH)2. From diazo-dibromo-benzene sulphonic acid and an alkaline solution of dioxynaphthalene. Needles (Griess, B. 11, 2199). Bromo -sulpho - toluene -azo- bromo -toluene sulphonic acid N,(CdHJBrMe.S03H)2 [1:?:4:5]. From potassic bromo-£>-toluidine sulphonate (of Jenssen) and KMn04 (Kornatzki, A. 221, 186). Red tables with pointed ends. Salts. — KfA" 4aq.— BaA" 5aq.— CaA" 4 |aq.— PbA" 5aq, Chloride. — [226°]. Groups of red prisms. Amide. — [above 260°] : red powder. Di - bromo - sulpho - toluene - azo - di - bromo- toluene sulphonic acid N2(C6HBr2Me.S03H)2 [1:?:?:2:5]. From potassic dibromo-o-toluidine sulphonate (of Hayduck) and KMnO, (Kornatzki, A. 221, 188). Blood-red plates. Salts.— KjA"2aq.— BaA"9aq.— CaA"8aq.— PbA"9aq. Chloride. [243°]. Red swallow-tailed plates. Amide.— [218°]. Powder. Di - butyl -p - amido - benzene -azo-di - butyl - aniline (C.H^N.C.H,— N2— CbH4N(C4Ha)2. Di- butyl-aniline-azyline. [158°]. Red needles. Formed by passing NO through an alcoholic solution of di-butyl-aniline. Periodide. — B"4I6: dark crystals with blue reflection (Lippmann a. Fleissner, B. 15, 2142 and B. 16, 1421 ; M. 3, 713). m-Carboxy - benzene - azo - aceto - acetic acid C6H4(C02H) — N2 - CHAC.CO.H. Formed by the action of the sulphate of m-diazo-benzoic acid upon acetoacetic ether in alkaline aqueous solution (Griess, B. 18, 962). Small yellow plates or needles. Soluble in alcohol, nearly insoluble in water. Bitter taste. o - Carboxy - benzene - o - azo - benzoic acid [2:1] C6H4(CO2H)— N2— C8H4.C02H [1:2]. o-Azo-benzoic acid. [238 ]. Mol. w. 270. From o-nitro-benzoicacid and sodium-amalgam (Griess, B. 10, 1868). Dark yellow hair-like needles. Insol. water ; m. sol. alcohol. Salts .—BaA" 7aq.— BaA" 9aq.— Ag-A". Ethyl ether Et.jA". [139°]. From o-nitro- benzoic ether by sodium-amalgam. Scarlet needles (Fittica, J. pr. [2jl7, 216). TH-Carboxy-benzene-w-azo-beazoic acid N4(CliH4.C02H).j [1:3]. m-Azobenzoic acid. From m-nitro-benzoic acid by sodium-amalgam (Strecker, A. 129, 134). Amorphous powder, decomposed by heat, v. si. sol. water, alcohol, and ether. Gives phenazine when distilled with lime. Its copper salt gives azobenzene on distillation. HgO and iodine gives an amor- phous di-iodo-derivative, C,4HgI2N2O4 (Benedikt. B. 8, 386). Salts.— BaA" 5aq.—Ag.,A". Ethyl ether Et,A". [99°]. By theaction of EtI on Ag.A" Golubeff (B. 7, 1651) obtained two bodies isomeric with this ether, one melting at 76°, the other being a monobasic acid. p-Carboxy-benzene-p-azo-benzoic acid N.,(CdH4.CO2H)2 [1:4]. From p-nitro-benzoic acid and sodium-amalgam (Beilstein a. Reichenbach, A. 129, 144 ; Biltinger, A. 135, 154). Formed, together with azoxybenzoic acid, by boiling nitro-benzil with alcoholic KOH (Zinin, Z. 1808, 563). Flesh-coloured amorphous powder, insol. water, alcohol, and ether. Gives phenazine when distilled with lime. Salts. — (NHJ.jA"aq. — Na2A".— CaA"3aq.— BaA".— Ag-jA''. Ethyl ether EtjA". [88°] (Fittica, J. pr. [2] 17, 216). m-Carboxy-benzene-azo-malonic acid CliH4(C0.2H)— N2— CH(C02H)2. Formed by the action of the nitrate of m-diazo-benzoic acid on malonic ether in alkaline aqueous solution (Griess, B. 18, 962). Microscopic orange needles or plates. Easily soluble in alcohol. Carboxy - benzene - azo - di-me thy 1 -amido-ben- zoic acid 0^(00.^) N2.CttH3NMe2.C02H. From m-diazo-benzoic acid and dimethyl-m-amido- benzoic acid (Griess, B. 10, 525). Brown pp. m-Carboxy-benzene-azo-nitro-methane CdH4(C02H).N2.CH_(N02). Formed by adding the nitrate of ?w-diazobenzoic acid to a dilute aqueous alkaline solution of nitromethane (Griess, B. 18, 961). Yellowish-red plates. Sol. hot alcohol and ether, v. si. sol. water. m-Carboxy-benzene-azo-(/3)-naphthol C6H4(CO.,H)— N2— C10H6(OH). [235°]. Prepared by the action of m-diazo-benzoic acid on an alkaline solution of (S)-naphthol (Griess, B. 14, 2035). Reddish-yellow needles or plates. Sol. hot alcohol, si. sol. cold alcohol and ether, insol. water. Salts : A'-jBaS^aq : red microscopic needles. A'K2aq : easily soluble yellow needles or plates. Ethyl ether A'Et. [104°]. Yellowish- red needles or plates. Sol. ether, insol. water. Amide. — Slender orange needles. 81. sol. alcohol and ether, insol. water. m - Carboxy - benzene-azo - (/3) - naphthol sul- phonic acid C.H^CO.H)— N2— CIOHS(OH)(HS03). Prepared by the action of m-diazo-benzoic acid on an alkaline solution of (/3)-napbthol sul- phonic acid (Griess, B. 14, 2036). Brown needles or plates. Sol. hot water, si. sol. cold water and alcohol, insol. ether. Dyes wool and silk a splendid orange. — A"2H2Ba4aq : orange pp. of slender needles. m-Carboxy-benzene-azo-(/9)-naphthol- di-sul- phonic acid C6H4(C02H).N2.C10H4(OH)(HS03)2. Prepared by the action of m-dlazobenzoic acid on (£) -naphthol- (a) -disulphonic acid in alkaline solution (Griess, B. 14, 2037). Yellowish-red microscopic needles. Dyes silk and wool an orange scarlet. AZO- COMPOUNDS. 381 Salts. — BaHA'"6aq: red crystalline pp. — Ba3A'"2 12aq : red microscopic needles. Carboxy-benzene-azo-phenol v. Oxy-benzene- azo-benzoic acid. Di-carboxy-benzene-azo-phthalic acid C6H3(CO,H)2— N2 -C6H,,(CO,H),. Azo-phthalic acid, [about 250°]. Prepared by reduction of nitro-phthalic acid with sodium-amalgam (H. Miiller; Claus a. May, B. 14, 1330). Small yellow needles : si. sol. water, alcohol, and ether. Salt s. — AivNa4 lOaq : yellow monoclinic prisms, v. sol. water. — AlvK46aq: long yellow needles. — AlTMg218aq: large orange crystals. — AlvAg4 : yellow insoluble pp. — A'"Ba2 : yellow insoluble pp. Di-carboxy-benzene-azo-tere-phtltalic acid [5:2:1] CBHa(C02H)2-N2-CBHs(C02H)2 [1:5:2]. Azo-terephtlialic acid. Formation. — 1. By oxidation of hydrazo- terephthalic acid with nitrous acid. — 2. By reduction of nitro-terephthalic acid with sodium- amalgam (Homolka a. Low, B. 19, 1092). Yellow needles. Sol. alcohol and ether, si. sol. water. Decomposes above 200°. Carboxy -naphtha! ene - azo - (/3) -naph thole acid C10Hti(CO,H)— N2-C10H6(CO,H). From a nitro- (j8)-naphthoic acid by ammonium sulphide (Rakowsky, B. 5, 1022). eoro-Carboxy-toluene-azo-phenyl-acetic acid CO.,H.CH.,.C«H4— N2— CBHl.CH2.C0ltH. S. (cold alcohol) 0-375; (hot alcohol) 1'57. Insol. hot water, ether, and benzene. Does not melt below 300°. Formed by the action of sodium amalgam on nitro-phenyl-acetic acid [151] (Wittenberg, Bl. [2] 43, 111). Carboxy - toluene - azo - toluic acid [5:2:1] CBH,Me(CO2H)-N2—C(jH3MeC02H[l:5:2]. Azo-p-toluic acid. [184°]. From nitro-jj-toluic acid by sodium amalgam (Fittica, B. 7, 1358). Minute yellow needles; m. sol. boiling water, v. sol. alcohol. p - Chloro - benzene - azo - benzene p-sulphonic acid [4:1]C«H4C1— N2— C6H4(S03H) [1:4] [148°]. Formed by warming ^-chloro - azo - benzene with fuming sulphuric acid (10 p.c. S03) at 60°-70°. Brown needles ; v. e. sol. water and alcohol. It is reduced by SnCl2 to ^>-chloro-aniline and p- sulphanilic acid. Salts.— A'Na: large orange-yellow pearly plates or small needles; si. sol. cold water. — A'jBa : glistening flesh-coloured needles. — The K, Mg, Ca, Ag, Cr, and Fe, salts are white to dark-yellow needles ; the Cu salt forms green plates ; all are sparingly soluble. Chloride CBH4C1.N2.CBH4.S02C1 : [130°]; glistening red prisms, easily soluble in alcohol and ether. Amide CttH4Cl.N2.C<fH4.S02NH2 : [211°]; yellowish - brown prisms ; sol. hot alcohol, sparingly in ether and cold alcohol, insol. water (Mentha a. Heumann, B. 19, 2972). m-Chloro - benzene - m-azo - chloro - benzene [1:3] C^H.Cl— N2— CBH4C1 [1:3]. Azo-chloro- benzene [101°]. Obtained by acting with Fe.,ClB on m-di-chloro-hydrazo- benzene in alcoholic solution (Laubenheimer, B. 8, 1025). Orange needles (from alcohol). p-Chloro-benzene-p-azo-chloro-benzene [4:1] CBH4C1— N2— CBH4C1 [1:4]. [184°]. Fromp- chloro - benzene - p - azo - nitro - benzene and alcoholic potash (Willgerodt, B. 15, 1002) ; or from di-chloro-azoxybenzene and fuming H,S04 (Heumann, B. 5, 913, 918). Yellow needles". p - Chloro - benzene - azo - chloro -b - n zone sul- phonic acid [4:1] C.H.Cl.Nj.C.HjCl.SOj.H [1:4:?]. Prepared by sulphonation of the preceding body (Calm a. Heumann, B. 13, 1183; 15, 2558). Slender reddish-yellow needles. Sol. water and alcohol. Salts . — A'Na : golden plates, si. sol. cold water. — A'K : reddish-yellow glistening plates, sol. hot water, and alcohol. — A'Ag. — A'.,Ba : yellow crystalline pp. — A'2Ca : golden yellow plates. — A'2Pb : orange glistening plates. Chloride C12H7C12N2S02C1 : [161°]. Long orange-red needles. Chloro - benzene - azo - chloro - phenol [3:1] C1.C6H4— N2— CBH3C1(OH) [1:3:?]. [115°] Formed by the action of fuming H2S04 on m-di-chloro-azoxy benzene (Schultz, B. 17, 465). Brown plates. Chloro-benzene-azo-chloro-nitro-benzene [4:1] C.HjCl-Ni-CACltNOJ [1:4:?]. [210°]. Prepared by reducing di- chloro -nitro -azoxy- benzene with cold alcoholic NH4HS (Calm a. Heumann, B. 13, 1184). Yellow needles. SI. sol. alcohol. m - Chloro -benzene - azo - di -methyl - aniline [3:1] C6H4C1— N2— C.H.NMe, [1:4]. [98°]. Yellow plates. Tolerably soluble in alcohol. Pre- pared by adding sodium nitrite (1 mol.) to a solution of m - chloraniline (1 mol.) and di- methylaniline (1 mol.) in dilute H2SO4 (Staedel a. Bauer, B. 19, 1955). p-Chloro-benzene-p-azo-nitro-benzene [1:4] CBH4C1.N2.C6H4(N02) [1:4]. [133°]. Formed by nitration of p-chloro-azo-benzene with fuming HN03. Yellow needles ; v. sol. acetic acid and hot alcohol, si. sol. cold alcohol, insol. water. It is reduced by SnCL2 to p-chloro-aniline and p- phenylene diamine (Mentha a. Heumann, B. 19, 2971). p-Chloro-benzene-azo-phenol CBH4C1— N2— CSH4(OH). [152°]. Formed by gently warming p-chloro-diazo-benzene-chloro- anilide with phenol, p-chloraniline being elimi- nated. Reddish-yellow needles (Heumann a. Oeconomides, B. 20, 906). Cumene-azo-cnmene PrCBH4 — N2 — CBH ,Pr. Azo-cumene. [108°]. From nitro cumene, [- 35°], by sodium-amalgam (Pospekhoff, J. R. 1886, 49). Thin yellow leaflets, si. sol. cold alcohol. ^ - Cumene -azo -^-cnmenol [2:4:5:1] CBH,(CH3)3.N2.C0H(CH:J)3.OH [1:3:5:6:2]. [148°]. Formed by combining di-azo-cumene chloride (from ^-cumidine) with i^-cumenol [70D] (Liebermann a. Kostanecki, B. 17, 885). Orange needles. Insol. alkalis. Dissolves in H.SO, with an orange colour. No nitrogen is evolved on boiling with HC1. 4/-Cumene-azo-4>-cumidine [2:4:5:1] CdH,Me3.N2.C0HMes.NH2 [1:2:4:5:6]. [139°]. Prepared by the action of cumidino hydrochloride upon diazo-cumene-cumide (di- azo-amido-cumene) dissolved in cumidine (Nol- ting a. Baumann, B. 18, 1147 ; Bl. [2] 42, 335). Orange plates (from alcohol). V. sol. ether. On reduction with SnCl2 it yields cumidine and cumylene-o-diamine. Salt. — B'HCl : yellow crystalline powder ; readily loses its HC1 ; dis- solves in phenol with a yellowish-brown colour. Cuminic-azo-cuminic acid rrCuHJ(CO,H)-N2-C6H:il>r.COiH. [2803]. From 382 AZO- COMPOUNDS. nitro - cuminic acid and sodium - amalgam (Alexeeff, Bl. [2] 38, 552 ; 42, 321 ; J. It. 1»82, 198 ; Alexeeif a. Kissel, BL [2] 40, 72). Ethers.— Me2A".[166°].—Et.,A".[1040-10S0]. Cymene-azo-cymene C..H3MePr— Nj-C^HsMePr. [86°]. From nitro- cymene by sodium-amalgam (Werigo, Z. 1864, 721). Cherry-coloured plates. Ethyl - amido - benzene - azo - benzene - p - sulphonic acid [4:1] C6H4(S03H).N2.CdH4.NHEt [1:4]. p - Sulpho - benzene - azo - ethyl - aniline. [c. 244°]. Obtained by combining p-diazo- benzene-sulphonic acid with ethyl-aniline in acid solution. Steel-blue needles. Nearly iusol. alcohol and cold water, si. sol. hot water. The sodium salt (NaA') forms orange-red plates. On reduction with (NH4)2S it yields mono-ethyl-p- phenylene-diamine and jj-sulphanilic acid (Bernthsen a. Goske, B. 20, 929). Di - ethyl -p - amido - benzene - azo - di - ethyl - aniline C6H4(NEt,)— N.2— C6H4(NEt2). Di-ethyl- aniline-azyline. [170°]. Prepared by passing NO through an alcoholic solution of di-ethyl- aniline ; yield 50 p.c. of the theoretical. Red monoclinic crystals, a:b:c = l: '7108: -9493. 0 = 90° 30'. V. sol. chloroform, si. sol. cold alcohol. Reactions. — 1. Nitrous acid acting on the acetic solution gives p-nitro-di-ethyl-aniline. — 2. On reduction it yields tt-di-ethyl-p-phenylene- diamine. — 3. Heated with ethyl iodide at 100° it gives tetra-ethyl-p-phenylene-diamine. — 4. Mel at 100° gives di-methyl-di-ethyl-p-phenylene- diamine. Salts.— B'^CLPtCV small brownish-red trimetric tables. — F errocyanide B"2H4FeCy6 : brown plates.— Pic rate B'^CaH.^NO.JsOH^ : yellow sparingly soluble needles (Lippmann a. Fleissner, B. 15, 2136; 16, 1415; M. 3, 286, 788). Di-ethyl-amido-benzene-azo-toluidine Acetyl derivative [4:1] C6H4(NEt2)— N2— C6H3Me(NHAc) [1:6:3]. [159°]. Fromdiazotised acetyl-tolylene-diamine C6Hs(NH2)Me(NHAc) [1:6:3] and di-ethyl-aniline (Wallach, A. 234, 359). o-Ethyl-benzene-o-azo-ethyl-benzene [2:l]CBH4(C2Hs)-N2-CtiH4(C.Hi)[l:2].[470corr.]. Formed by reduction of o-nitro-ethyl-benzene with zinc dust and alcoholic NaOH (Schultz, B. 17, 473). Long red dimetric prisms, a:c = 1: -3455. V. sol. alcohol. By treatment with SnCLj and HC1 in alcoholic solution it yields a di-amido-di- ethyl-diphenyl. jp-Ethyl-benzene-p-azo-ethyl-benzene [4:l]CsH4(C.^[s)-N2-C(>H4(C,H5)[l:4].[630corr.J. (above 340°). Formed by reduction of ^-nitro- ethyl-benzene with zinc-dust and alcoholic NaOH (Schultz, B. 17, 475). Orange-red plates or thick prisms. V. sol. alcohol. By treatment with SnCl2 and ILjSO4 in alcoholic solution it yields a di-amido-di-ethyl-diphenyl. 25-Ethyl-phenyl- amido-benzene-^ - azo - ethyl- di-phenylamine [4:1] C6H4NEtPh— N2— C6H4NEtPb [1:4]. [178°]. From ethyl-di-phenyl-amine and NO (Lippmann a. Fleissner, M. 4, 796). Monoclinic red crystals. Ethyl-pytrol-azo-(/3)-naphthalene C10H7.N2.C4H,,NEt. [74°]. Obtained by adding (/3)-diazo-naphthalene chloride (1 xnol.) to ethyl- pyrrol (1 mol.) dissolved in alcohol containing sodium acetate. Thick red tables. Sparingly soluble in dilute HC1. Dissolves in cone. H.S04 with a dark reddish-yellow colour. The platino- chloride forms small sparingly soluble red needles (0. Fischer a. Hepp, B. 19, 2258). Ethyl-pyrrol-azo-p-toluene C6H4Me.N2.g = CH C6H4Me.N2.C4H3NEt probably NEtj HC = CH [62°]. Formed by adding ^>-diazo-toluene chloride (1 mol.) to an alcoholic solution of ethyl-pyrrol (1 mol.) containing sodium acetate. Thick red prisms. Dissolves in cone. BLjSO4 with a yellow colour, in dilute HC1 with a reddish yellow colour. The platino-chloride forms sparingly soluble red needles (0. Fischer a. Hepp, B. 19, 2257). lodo-carboxy-benzene-azo-iodo-benzoic acid 0^1(00.^)— N2— 0,^1(00.^). Azo-iodo-ben- zoic acid. From m-amido-benzoic acid, iodine, and HgO (Benedikt, B. 8, 386). Mesitylene-azo-mesitylene C,,H2(CH3)3— N2— C6H;(CH3)S. Azo - mesitylene. [75° corr.]. Prepared by oxidising an aqueous solution of mesidine hydrochloride (5 pts.) with a solution of 45 pts. of potassium ferricyanide and 10 pts. of KOH (Schultz, B. 17, 476). Thin red needles. Sol. hot alcohol. It does not appear to yield a hexa-methyl-benzidine by treatment with SnCl2 and HC1 in alcoholic solution. Methyl - amido - benzene - azo - benzene - sul- phonic acid[4:l] C<jH4(S03H).N2.C6H4.NHMe [1:4]. p-Sulpho-benzene-azo-methyl-aniline. Obtained by combining jj-diazo-benzene sulphonic acid with methyl-aniline in acid solution ; yield 30 p.c. of theoretical. Also formed by the action of cold dilute acids upon j»-sulpho-diazo-benzene- methyl-anilide C6H4(S03H).N2.NMeC(>H5. Steel blue needles, si. sol. water. The sodium-salt (A'Na) forms large orange-red plates, v. sol. hot water. On reduction with (NH4).,S it yields p- sulphanilic acid and mono-methyl-p-phenylene diamine (Bernthsen a. Goske, B. 20, 925). Di-methyl-aniido-benzene-azo-benzene-sulph- onic acid [4:1] CBH4(NMe,)— N2— C^SO^ [1:4] Helianthin, or Orange III. Preparation. — 1. From dimethylaniline and |j-diazobenzene sulphonic acid (Griess, B. 10, 525). — 2. Dimethylamido-azobenzene (1 pt.) is dissolved in 20 pts. cold sulphuric acid of 30 p.c. anhydride value and allowed to stand for 24 hours (Mohlau, B. 17, 1491). The absorption spectrum has been mapped by Hartley (C. J, 51, 192). Di-methyl-amido-benzene-azo-benzoic acid [4:1] C6H4NMe2— N2— C,,H4.Cp,H [1:3]. From di-methyl-aniline and m-diazo-benzoic acid (Griess, B. 10, 525). Di - methyl - amido - benzene - azo-di-methyl- aniline [1:4] C6H4(NMe2)— N2— C6H4NMe2 [1:4] [266°]. Dimethylaniline-azyline. Bed needles. Formation. — 1. By diazotising ^j-amido-di- methyl-aniline and combining the diazo-com- pound CBH4(NMe2).N2.Cl with dimethylaniline (Nolting, B. 18, 1143).— 2. By passing NO through an alcoholic solution of di-methyl- aniline for several days. Reactions. — 1. Nitrous acid acting on the acetic acid solution gives ^-nitro-di-methyl- aniline. — 2. On reduction it gives w-di-methyl-jj. phenylene-diamine. AZO- COMPOUNDS. 383 Salts.— B"H,Cl.2PtCl4: dichroic crystalline powder.— Pier ate B"CaH,(NO,)JOH + C,H,OH : glistening green needles (Lippmann a. Fleissner, B. 15, 2136 ; 16, 1415 ; M. 3, 708). Di-methyl-amido-benzene-azo-;> toluene C7H7— N7-CBH4.NMe2. [168°]. Golden plates. Easily soluble in alcohol and ether. Preparation. — A solution of 65 pts. of NaN02 (100 p.c.) and 35 pts. NaOH in 465 pts. of water is slowly added to a cooled solution of 100 pts. of ^j-toluidine, 113 pts. of dimethylaniline and 200 pts. of HC1 in 300 pts. of water. On reduction it yields ^-toluidine and di- methyl-p-phenylene-diamine. The hydrochloride and sulphate form violet prisms, giving a red solution in alcohol (Mohlau, B. 17, 1492). Di-metb.yl-amido-be;izene-azo -p- toluene-sul- phonic acid C7Hti(HS03).N2.CBH4.NMe2. Formed by the combination of p-diazo-toluene sulphonic acid (Me:HSO3:N2= 1:3:4) with dimethylaniline (Mohlau, B. 17, 1493). Dark-violet prisms. Soluble in water and alcohol with an orange colour, insoluble in ether. The sodium salt forms orange glistening plates. Di-methyl-amido-benzene-azo-toluidine [4:1] C6H4(NMe,)-N2— C6H3Me(NH,) [1:6:3] [145°]. From its acetyl derivative [200°] which is formed by the action of diazotised-acetyl- tolylene-diamine C6H3(NH.!)Me(NHAc) [1:6:3] upon di-methyl-aniline (Wallach, A. 234, 355). Di-methyl-amido-benzene-azo-toluidine [4:1] C8H4(NMe2)— N2— C8KL,Me(NH2) [1:4:3] [215°]. From its acetyl derivative, [19~2°] which is formed by the action of diazotised acetyl- tolylene-diamine C6H3(NH2)Me(NHAc) [1:4:3] upon di-methyl-aniline (Wallach, A. 234, 359). £>-Methyl-pb.enyl-amido-benzene-azo-inethyl- di -phenyl-amine [4:1] CBH4NMePh.N2.CBH4NMePh [1:4] [150°]. Yellow crystals, got by the action of NO on methyl-diphenyl-amine (Lippmann a. Fleissner, M. 4, 798). (a)-Naphthalene-(a)-azo-naphtb.alene [o] C10H7.N2.C10H7 [a]. [190°]. Prepared by boiling diazo-naphthalene-azo-naphthalene with alcohol : 1 pt. of naphthalene-azo-naphthylamine is dissolved in 100 pts. of 95 p.c. alcohol and 5 pts. of H;S04 are added; the still warm solution is then treated with a saturated solution of (1 mol. of) NaN02 ; the fluid is heated and finally boiled for a few hours, and the azonaphthalene precipitated by water. It is recrystallised by dis- solving it in hot aniline and adding alcohol (Nietzki a. Goll, B. 18, 298, 3252). Steel-blue crystals. Sublimes in thin yellow plates. Soluble in aniline, sparingly in alcohol. It dissolves in cold HjSO4 with a blue colour, but on heating the solution to about 180° it becomes violet and exhibits a red fluorescence. By alcoholic NH4HS, or zinc-dust and alcoholic KOH, it is reduced to hydrazonaphthalene. (a)-naphtb.alene-($)-azo-naphtb.alene [a]C10H7.N2.C,0H7[/3]. [136°]. Obtained by diazo- tisation of (£)-naphthalene-;p-azo-(a)-naphthyl- amine and boiling with alcohol. Dark-brown plates with steel-blue reflex. Sol. alcohol, acetic acid, &c. Dissolves in cone. H2S04 with a violet colour (Nietzki a. Gottig, B. 20, 612). Laurent's naphthase [275°], got by heating nitro- naphthalene with zinc dust, or (o)-naphthyl- amine with PbO, has been regarded as naphtha- lene-azo-naphthalenc, but Witt has lately (B. 19, 2794) shown it to be an azine C20H12N2 v. (a£)-NAPHTHAZiNE (Laurent, A. 109, 384 ; Doer, B. 3, 291 ; Alexeeff , B. 3, 868 ; Schichuzky, B. 5, 365 ; Klobulowsky, B. 10, 570, 772, 873). Naphthalene-p-azo- (a) -n aph t ho 1 C10H7— N2— CIOHBOH. Formed by adding di- azo-naphthalene chloride to a solution of (a)- naphthol in NaOHAq ; it is ppd. by HC1. Crimson powder. Soluble in alkalis forming crimson solutions (P. F. Frankland, C. J. 37, 752). 