PERKIN ON SOME DERIVATIVES OF ANTHRACENE. 13 11.-On some Derivatives of Antlwacene. By W. H. PERKIN,F.R.S. INthe “Chemical News ” of the 22nd July last I published a short note upon some new derivatives of anthracene and re- ferred more particularly to the products resulting from the action of atllphuric acid upon dichlor- and dibromanthracene I now beg leave to lay before the Society a more detailed ac-count of my experiments in this direction with the addition of* a few other observations relating to the history of anthracene. PERKIN ON SOME DERIVATIVES OF ANTHRACENE. DICHLORANTHRACENE. I have found it convenient to prepare this substance by passing chlorine gas over benzole holding about one-fifth its weight of purified commercial anthracene in suspension until the mixture becomes a crystalline pasty mass.The product is then thrown on a linen filter drained and well washed with cold benzole. It is then dried and further purified first by distillation and then by two or three crystallisations from benzole. Thus obtained it presents itself as golden-yellotl coloured needles. Analysis of this product gave the following numbers :-I. 03151of substance gave -3624 of AgC1. 11. ,6258 of substance gave -7333 of AgC1. 111. *3607of substance gave *8974 of CO and *I073of H20. IV. 03143of substance gave -1833 of CO and 00957 of H20. These numbers agree with the formula- as the following comparisons show :-Theory. Experiment. / A \ -I. 11. 111. IV. C,,... 168 68.02 -67.85 6'7.97 H .... 8 3.24 -3-30 3-38 GI,. .. . 71 28-74 28.45 28.95 -7 7-247 100*00 It will be observed that theRe results perfectly agree with those of Graebe and Liebermann." Dichloranthracene when gently heated sublimes in beautiful needles which may be obtained of considerable size. It is fluorescent in the solid state as well as when in solution. * Ann. Chem. Pharm. Supp. pii 259 (1870). PERKIN ON SOME DERIVATIVES OF ANTHRACENE. When a boiling solution of dichloranthracene in benzole is added to a similar solution of picric acid the mixture assumes a dark orange-red colour and on cooling becomes filled with small bright red needles. These consist of a compound of dichloranthracene and picric acid. A determination of the di-chloranthracene in this body gave numbers closely approxi- mating to those required by the formula- DIBROMANTHRACENE.The product used in my experiments was prepared by Graebe's process*. It was however purified fist by distillation and then by crystallisation from Fenzole. Thus obtained it is of a golden-yellow colour. It gave on analysis the following numbers :-a3205 of substance gave *5864 of CO, and -0729 of H,O. These numbers closely agree with those required by the formula-'14=BBr29 as the following comparisons will show :-Theory. Experiment. C, ... . 168 Br .a * . 160 H ...... 8 - 50.00 47.62 2.38 49.9 -2-52 336 100*00 Like dichloranthracene this body produces a beautiful red compound with pic& acid.Action of Sulphuric A cid on Dichloranthracene. Dichloranthracene when submitted to the action of fuming sulphuric add dissolves forming a bright green solution and is at the aame time converted into a sulpho-acid. To prepare this acid one part of dichloranthracene is added * Ann. Ch. Phttrm Suppl. vii (1870). PERKIN ON SOME DERIVATIVES OF ANTHRACENE. to about five parts of fuming sulphuric acid and the mixture heated for a short time on the water-bath. It is then gradually poured into several times its bulk of water and treated with baric carbonate until all the sulphuric acid is neutralized. The acid solution when filtered off from the baiic sulphate is evaporated to a small bulk. When sufficiently concentrated it becomes on cooliiTg a slimy mass of minute orange-yellow coloured crystals which may be drained on a porous tile.This acid has not been analysed but from the composition of its salts evidently possesses the forrnula- I therefore propose €0 call it-Disul33hodaehloi.antliracenic Acid.-It is easily soluble in water from which it is pre-cipitated upon the addition of a little concentrated sulphuric or hydrochloric acid. It possesses a strongly acid taste and character. The dilute solutions of this acid and its salts are remarkably fluorescent but not so strongly as an alkaline srolution of pure 2Esculine. The colour of the fluorescence is blue. Xodic Di~u~ho~~c~lomnthracenale.-This salt can be obtained by neutralizing the acid with sodic carbonate or from tho calcic or crude baric salt by double decomposition.To ob-tain it from the latter the product of the action of sulphuric acid on dichloraiithracene is entirely neutralized with baric . carbonate. Sodic sulphale is then added ,in > the proportion of about five parts of dry salt to every ten parts of dichloran-thracene employed and the mixture well boiled; it is theu atered and the filtrate concentrated. On standing for some &me the new sodic salt separates iii small orange-red crystals. These are well pressed between bibulous paper and pmified by one or two crystallisations; dried at 150" C. they gave the following numbers on analysis :-I. *2254grm. of substance gave -0693 , Na,SO,. 11. -3449 , of substance gave *4694 , CO, and *0559 , H,O.PERKIN ON SOXE DERIVATIVES OF ANTHRACENE; These numbers give perceptages agreeing with those re-quired by the formula- c14H(jc19 {:::$ a8 the following comparisons will show :-Theory. Experiment. ’I. /-.11. -I C, ...... 168 37-25 37.11 H6 ...... 6 1-33 -1.80 C1,...... 71 15.74 Na,.. .... 46 10.20 S ..... 64 14-19 0 ...... -96 21-29 451 100*00 This salt dissoll-es easily in water forming an orange coloured solution. Bark Disu~hodich2oranthracenat~.-This salt is best obtained in the pure state by the addition of baric chloride to a solution of the pure sodic salt. It is then thrown down as a bright canary-yellow coloured precipitate nearly insoluble in water. The analysis of this salt gsve the following numbers :-I *2023grm.of substance gave *0859 , BaSO,. 11. -0845 , of substance gave ~0360 , BaSO,. 111. *1534 , of substance gave *0658 , BaSO,. IV. -4179 , of substance gave *4637 , CO, and 00560 , H,O. V. -4117 , of substance gave -4549 , CO,,and 00571 , H,O. VI. 03059 , of rjubstance gave ,3438 , CO, and 00448 ) H,O. VII. *5936 , of substance gave *6767 , CO, and 4878 , H,O. VOL XXIV. 0 18 PERKIN ON SOME DERIVATrCTES OF ANTHRACENE. These give percentages agreeing tolerably well with the formula-C14H6C1,Bav{:$ The following is a comparison of the theoretical and experi- mental numbers :-Theory. Experiment. F h 7 -I. 11 111. IT. v. VI. VII. CI~.... 168 30.99 --30.26 30.13 30.65 31.09 Hs....6 1-11 --1.48 1-54 1.62 164 Ba.... 137 25.28 24.96 25.05 25.22 --Clz.,.. 71 13-10 ----5 .... 64 11.81 ----06 .... 96 17.71 --542 10000 If to a hot solution of sodic disulphodichloranthracenate strongly acidified with hydrochloric acid baric chloride be added no change at first is observed but on standing a short time the above baric salt senarates as an orange-coloured I crystalline precipitate. The following numbers were obtained on analyzing a specimen prepared in this manner :-01723 of substance gave *0742of BaSO = 25.32 per cent. of barium. Xtrontic Disulphodichloratithvacenate.-On adding a solution of strontic chloride to a solution of sodic disulphodichloranthrtz- cenate no apparent change takes place; but if the solution be evaporated the new strontic salt separates in yellow crusts difficultly soluble in water.A specimen gave the following numbers on analysis :-03146of substance gave -1136 of SrSO = 17.21 per cent. of strontium. The formula Cl,H6C1,Sr”{ “3 so3 requires 17-77 per cent. Calcic ~isulphoclichlorantliracenate.-This salt may be ob-tained by neutralizing the product of the action of sulphuric acid on dichloranthracene with calcic carbonate filtering PERKIN ON SOME DERIVATIVES OF ANTHRACENE. off the calcic sulphate and evaporating the filtrate to dry-ness. The residue is extracted with water filtered and again evaporated. This salt is of a yellow colour and easily soluble in water. It is useful for the preparajion of the sodic salt by double decomposition with calcic carbonate.Action of Su&7~uricAcid upon Dibi3omanthracene. Dibromaiithracene dissolves in fuming sulphuric acid forming a sulpho-acid. This has not however been prepared in a pure state but from the examination of its salts it evidently possesses the formula- and may therefore be called disu&?Lodi6ro.rrianthracenic acid. It is crystalline and its dilute solutions are fluorescent as also are its salts but not nearly to the same extent as those of the cor- responding dichloro-acid. Sodic Disul&hodibromant?iracenate.-To obtain this salt one part of dibromanthracene is dissolved in the cold in about six or seven parts of fuming sulphuric acid and the mixture allowed to stand for an hour or two.It is then gradually added to several times its bulk of cold water well stirred and neutralized with baric carbonate. Sodic sulphate is then added in the proportion of about five parts of dry salt to every twelve parts of dibromanthracene employed and after boiling the resulting sodic salt is filtered off from the baric sulphate concentrated by evaporation over the water-bath and set aside to crystallise. It is then well drained and pressed from the mother-liquor and purified by two or three crystallisatioiis from water. Thus obtained it is of a yellow colour and crystallises in microscopic needles. It is easily soluble in water. It gave on analysis the following numbers :-I. 04676of substance gave- -1256 of Na,SO = 8-70p.c. sodium.11. -4809 of substance gave- *1311of Na,SO = 8-85p.c. sodium. 02 PERKIN ON SOME DERIVATIVES OF ANTHRACENE. The formula C,,H6Br2(1:$: requires 8-52 per cent. of sodium. Ban’c Disdphodibromnt h?*acenate.-This salt may be ob-tained in precisely the same manner as the corresponding disulphodichloranthracenate. It is obtained as a pale yellow precipitate. It gave on analysis the following result :-*5565of substance gave-*2026of BaSO = 21.41 p.c. barium The formula Cl,H6Br2Ba”{ ;$ requires 21-71 per cent. of barium. This salt is remarkable for its insolubility. If a boiling solu-tion of the sodic salt be strongly acidified with hydrochloric acid and bark chloride added the mixture which is for a few seconds perfectly clear becomes rapidly turbid with the formation of this salt which cannot be re-dissolved even by vigorous boiling notwithstanding the excess of hydrochloric acid present.Oxidation of Disull,hodicJdo~o-and DisubJLodibromanthracenic Acid.-These sulpho-acids when subjected to the influence of oxidizing agents rapidly decompose exchanging their chlorine or bromine for oxygen and are thus converted into disulphan-thraquinonic acid. Disulphodichloranthracenic Disulphanthraquinonic acid. acid. Ci*H6Br!2 { HSO + 0 = C,,R,(O,)” {E:: + BrBr Disulphodibromanthracenic Disulphanthraquinonic acid. acid. An analogous result is also obtained by heatjng them with concentrated sulphuric acid the following regctions taking place :- PERKIN ON SOME DERIVATIVES OF ANTHRACENE.21 A quantity of disulphanthraquinonic acid prepared by heating disulphodiclzloranthracenic acid with concentrated sulphuric acid was made into the baric salt,* and analysed. The fol-lowing results were obtained :-I. =2273of substance gave- -1040 of BaSO = 26.90 p.c. barium. 11. -3093 of substance gave- -1415 of BaSO = 26.89 p.c. barium. The formula C,,H60,Ba"2SO requires 27.23 p.c. Graebe and Liebermann have shown that dichlor-or dibrom-anthracene when oxidized also exchange their chlorine or bromine for oxygen yielding anthraquinone.? Whilst making the foregoing experiments I have often been struck with the remarkable fluorescence of many of the anthra- cene products anthracene itself when pure and in large crystals being one of the most beautifully fluorescent solid bodies I know of though curiously its solutions are comparatively poor in this respect.$ As this hydrocarbon aiid also its chlorine deri-vative which is fluorescent both in the solid state and in solu-X I may here remark that the baric disulphanthraquinonate although more soluble than the baric salts of the sulpho-acids obtained from dichlor or dibroman-thracene is Like them precipitated from hot solution in the preseuce of an excess of hydrochloric acid if the solution be not too dilute j a specimen prepared in this manner gave the following results upon analysis :--2135 grm.of substance gave -0981 BaS04 = 27.01 per cent. j theory 27.23. .t. When endeavouring to obtain some highly chlorinated anthracene derivatives some time since I came across a rather unexpected instance of this kind.A quantity of dichloranthracene was suspended in glacial acetic acid and chlorine passed through the mixture. On allowing this to stand a large quantity of a white product was obtained which when crystallised from benzole was analysed and gave of carbon 80.65 per cent. and of hydrogen 414 per cent. It was in fact anthraquinone which requires of carbon 80.77 and of hydrogen 3.85 and had been formed owing to the presence of a small quantity of water in the glacial acetic acid thus :-$ The anthracene used in these experiments was chemically pure and gave the following numbers on analysis :-I. 11. Theory. Carbon .......... .. 94-31 94.37 94.38 Bydrogen .,.,.,.. . 5 -68 5 98 5 -62 PERKIN ON SOME DERIVATIVES OF ANTHRACENE. tion are volatile it appeared to me interesting to examine them in the state of vapour. So far as I have gone however my experiments seem to show that the vapour of anthracene or dichloraiithracene is not fluorescent and moreover a ray of light sent through alength of about 4inches of the vaponr of either body still retained its power of rendering fluorescent solutions luminous. On sealing up anthracene in a long vacuum tube with platinum poles and allowing the discharge from an induction coil to pass through the tube nothing particular is observed except the beautiful fluorescence of the crystals of anthracene. On exa- mination with the spectroscope the light showed carbon and nitrogen lines the latter arising from the presence of a little air in the tube.Upon heating the tube however somewhat strongly so as to volatilise the hydrocarbon the ordinary colour of the discharge changed to a magnificent deep azure blue and what is remarkable is that this blue light when examined with the spectroscope is perfectly continuous and consists of blue with a little green. Dichloranthracene when treated in a similar manner g'ives an analogous result but suffers a good deal of decomposition aiithracene changing but little. These curious results do not appear to be due to the fluorescent character of the substances employed as naphthalene produces a similar effect the blue light though not so intense being coiitinuous.It must be observed however that this hydrocarbon undergoes considerable change becoming brown and oily. Anthraquinone heated in a vacuum tube in the same way gives a greenish blue light showing faint carbon bands. On exposing a solution of disulpho-dichloranthracenic acid to the light of one of the recent displays of the aurora borealis it was very strongly illuminated as might be expected moon-light on the other hand had no perceptible effect either upon it or an alkaline solution of esculin.