3c V.-On a New Class of Compounds coniaining Nitrogen iiz zuliich Hydrogen is replaced by Nitrogen. By PETER GRIESS. {Abstracted by the Author from the Philosophical Transactionn for 1865.1 ALL the different nitrogen-substituted compounds that I have studied up to the present moment may according to their com- position and their chemical deportment be arranged in two different classes. If the composition of amido-compounds be expressed by the gerieral formula C,H,,,, (NH3)"0,*) the dif- ference in the mode of formation of the two classes may be illustrated by the following equations :-Whilst thus in the first case the substitution of three atoms of hydrogen by one atom of nitrogen takes place in two atoms of the amido-compound it is in the second case confined to one atom Hence it is obvious that for every amido-compound there must be two corresponding nitrogen-substituted bodies.The conditions which have to be observed in order to lead the reaction at will either in the one direction or the other differ occasionally according to the special character of the amido-corn- pound ;but in general it may be taken as a rule that the action of nitrous acid upon neutral solutions of the amido-compounds gives rise to compounds of the first class whilst those obtained by em-ploying an acid solution belong to the second class. I haveup to the present moment chiefly submitted to minute * Chemisb are not agreed upon the rational constitution of amido-compounds. They are frequently referred to the ammonia-type and almost as frequently to the same type to which the nitro-compounds from which they are derived belong.In the latter case the group NH2is considered a8 repIacing one atom or NH3as taking the place of two atoms of hydrogen. Aniline can thus be written in three different ways and expressed by the three formule Cs%HJN? CfjHdH2W CJ&(HJY)". Phenglamine. Amidobenzol. Ammoniabenzol. The two latter formule appear to me to be capable of explaining in the most natural manner the formation of bodies in which nilrogen i8 substituted for hydrogen. CONTAINING NITROGEN ETC. 37 examination members of the first series of compouuds for instance diazo-arnidsbenzoic acid and diazo-amidobenzol ; the latter substance in order to give a practical illustration being formed according to the following equation :-2C6H,N + NHO = C,,H,,N -I-2H,O.As a representative of the second class may be taken diazo-dinitrobensol the formation of which takes place thus :-C,~T,(_\.:0,),NM20 + NHO = C,H,(NO,!,N,O + 2T1,O. To this last group belong also a number of compounds formed from organic bases the existence of which up to the present time I have communicated only in short notes as for instance diazo- benzol (C6H,N,) diazonaphthd &c. I have now had the oppor-tunity of submitting these bodies also to a more minute examina- tion and I will endeavour to communicate the results which 1 have obtained in this and several following papers. Here already I will mention that all these bodies are particularly distinguished by the great variety of their forms of combinatioii and that iza this respect they exhibit peculiarities not to be found elsewhere in the domain of organic chemistry.In the free state they are remarkable for their extraordinary instability whilst in their com- binations on the other hand they are comparatively stable. The following examinations were conducted therefore chiefly with the latter. Very conspicuous also are the physical properties of these peculiar substances as well as the great number of their products of decomposition ; in consideration of all these proper- ties they may be viewed as one of the most interesting classes of chemical compounds. I have avoided as much as possible discussing their rational constitution and have abstained from theoretical speculation.I maintain however that the two atoms (or the molecule) of nitro-gen N, they contain must be considered as equivalent to two atoms of hydrogen as is the case with the bodies described in my preceding papers and it is in accordance with this view that the names of the new compounds have been framed. In the present paper I intend to confine myself solely to the description of diazobenzol and its derivatives. Nitrate of diazobenzol is of special importance as the etarting point for the preparation of all the other derivatives? and 1will therefore give its description the precedence GRIESS ON A NEW CLASS OF COMPOUNDS Nitrate of IXuxo benzol C6H4N,.NHO,. This substance can be prepared in various ways; most readily however by acting with nitrous acid upon a solution of nitrate of aniline.This salt of aniline is not very soluble in cold water; therefore in order to obtain a concentrated solution of the new compoundj it is best Eo make a thick paste by grinding up a por-tion of the nitrate with water and submitting it to the action of the gas when the undissolved portion of the aniline-salt rapidly disappears and thc whole is converted into the uew body. The reaction being accompanied by considerable increase of tempera-ture it is necessary to keep the solution cool and to guard against passing a too-rapid current of the gas. The temperature of the solu- tion should not rise much above 30" C. The operation is inter-rupted as soon as the whole of the aniline has disappeared.This can be ascertained by adding a little strong solution of potaesa to a portion of the liquid on a watch-glass when if no more aniline is liberated it may safely be inferred that the reaction is com-plete. The nitrate of diazobenzol is almost insoluble in ether and even in ether mixed with much dilute alcohol in consequence of which it may readily be obtained in a crystalline state thus :-the soiution is first filtered to remove traces of a brown resin then mixed with about three times its volume of strong alcohol and ether added until the precipitation is complete. The crystals are allowed to subside and then filtered from the mother-liquor. The small quantity of' the new body which remains in the mother- liqsor may be neglected altogether as its recovery is accompanied with great difficulty.To remove the last traces of colouring matter the crystals are taken up with eold dilnte alcohd and re-precipitated by the addition of ether when they are obtained as long white needles. Analysis as will be shown further proves that the new com-pound has the formula C6H4N,.NH0,. Its formation may be explained by the following equation :-CkH7N.NH0 + NHO = C6H4N2.NH0 -I-2H@. Nitrate of aniline. Nitrous acid. Nitrate of diazobenzol. Water. - Another method of preparing nitrate of diazobenzol is based Upon the action of nitrous acid upon diaao-amidobenzot a body CONTAINING NITROGEN ETC. 89 described in a previous communication. On dissolving this latter compound in cold ether and passing a current of nitrous acid gas through the solution long acicular crystals of the new substance soon appear.The action should be continued as long as crystals form. The compound so obtained is collected on a filter and washed with ether. The reaction is expressed by the folIowiag equation :-C12H,,N + NHO + ZNHO = 2(C6H,N,.NH0,) + 2H,O. Diazo-amido-Nitrate of diazobenzol. benzol. However elegant and simple this method of preparation of the nitrate of diazobenzol may appear it will scarcely ever be em-ployed since it involves the previous preparation of diazo-amido-benzol a body which it is rather troublesome to obtain in large quantities. Xitrate of diazobenzol can also be procured by the direct action of nitrous acid upon a mixture of aniline with about four times its volume of alcohol.The gas is passed into the alco- holic solution till on the addition of ether to a small portion of it a copious precipitation of white acicular crystals is produced. . When this point is reached the whole of the reddish-brown soh-tion is mixed with ether and the precipitate purified as already described. This method of preparing the nitrate however is not suitable when large quantities have to be prepared. It is similar in prin- ciple to the preparation by means of diazo-amidobenzol since to all appearance the aniline is first converted into this compound. The methods just described although simple will only give favourable results when strict attention is paid to the directions given above; for it happens sometimes and especially when the temperature of the solution is allowed to rise too high that a copious evolution of nitrogen gas ensues which cannot be stopped by any means before the whole of the substance has been de..stroyed. By employing the first of the above processes it is sometimes found that on' the addition of ether to the weak alcoholic solution of the crude compound no crystals separate but that an aqueous layer is deposited at the bottom of the vessel. This however happens only when an insufficient amount of alcohol has been originally added to the solution because in this case the ether not being able to mix with the liquor causes no separation of GlLIEM ON h NEW CLASS OF CO;1I[POUKDS crystals to take place.If this occurs it is best to remove the ethereal liquor and dilute the residuary aqueous solution with strong alcohol when on the addition of ether crystallisation invariably ensues. The nitrate of diazobenzol by whatever method it may have been prepared crystallises in long white needles which have been obtained several inches long and are very soluble in water less so in alcohol and almosl insoluble in ether and benzol. They can be dried over sulphuric acid without undergoing any change. Heated even below 100' C. they explode with unparallelled violence far surpassing that of fulminating mercury or iodide of nitrogen. About a gramme of this substance causes by its explosion a con-cussion like that produced by firing a pistol.The destructive action cf such an explosion is likewise extreme. Iron slabs of several lines in thickness were found smashed to atoms when 8 somewhat larger quantity was esploded upon them. Friction pressure and concussion also cause it to explode. The smallest particles of this substance accidentally dropped upon the floor of a room when trodden upon mhen dry gave rise to a series of explosions attended witti flashes of' light. The properties of the nitrate of diazobenzol render it absolutely necessary that the greatest precaution should be observed when manipulating it. The portion of the substance required for analysis having been well washed with ether,* was placed in a platinum crucible and dried over sulphuric acid.Concussion or pressure had to be care-fully avoided especially with the dry substance on account of its great explosiveness. * When it is intended to recover the ether employed in thc preparation of nitrate of diazobenzol it is advisable in order to avoid explosions to shake the ethereal mother-liquor first with a little water so as to dissolve any traces of the diazo-corn- pound suspended in it. I have had amost danger0us:explosion byneglecting this simple precaution. A large quantity of ether which had been employed for the precipita- tion of the new compound from it<salcoholic solution had accumulated. From thie liqllid a few crystals were observed to have separated. Their number seemed however to be SO small that it was deemed unnecessary to remove them from thevessel containing the ethereal liquid for distillation.As soon as the vessel became warm in the water-bath and before the boiling-point of the ether had been reached a fearful explosion took place shattering the whole of the distilling apparatus to pieces and setting fire to the ether the flame of which spread most alarmingly through the laboratory. The gas-flames which were burning at the time in the room were suddenly extinguished by the violent pressure upon the atmosphere and zd1 those working in the laboratory (who fortunately escaped unhurt) mere for a moment deprived of their breath. The explosive properties of the nitrate of diazo. benzol perhaps at a filtilr3 period find practical applicstiop CONTAISTNG NITROGER ETC.4L For the above mentioned reasons I abstained from analyzing this compound in the usual manner especially as I had opportu- nities of ascertaining the eompositior of analsgous but less dan- gerous compouiids by the ordinary analytical methods. I have however been enabled to arrive at a knowledge of the composition of nitrate of diazobenzol by the very interesting change which an aqueous solution uadeigoes by the action of heat. By ebullition the wmpound is transformed under the influence of the water into carbolic acid nitrogen and nitric acid; and by estimating the quantities CJf the two latter products I have arrived at thc trw cornposition of the explosive substance CGH,N,.NE-IO + fI,O = C6H60 f NHU fN,. Nitrate of diazobcnzol. Carbolic acid.The method employed for the determination of the quantity of nitrogen evolved by the ebullition of the aqueoiis solution of the explosive compound is as follows :-The solution was introduced into a flask and a stream of carbonic acid gas passed through it. When the air was expelled the delivery-tube was placed under a graduated cylinder containing solution of potassa and the contents of the flask heated to ebullition.* I. 0.605 grm. of the compound treated as above gave 80.4 cub. centims. of nitrogen at Oo and 760 millims. bar. pres-sure = 0.101 grm. of nitrogen or 16.70 per cent. Theory. Experiment. N = 17.77 16.70 11. *492grm. of substance dissolved in water and boiled required for neutralisation 29.5 cub. centims. of standard alkali solution corresponding to 0-185 gym.of nitric acid or 37-77 per cent. Calculated. Pound. (---h---7 C6114N .. 190 62.27 NHO,.. .. 63 37.73 37.77 L--253 100.00 Subhate of Diaxobenzol C,H,N,.SH,O,. Acid sulphate of aniline when treated with nitrous acid is f In all analyses mentioned herein the analyzed substance8 are understood ioh deaiccated by sulphuric acid previoudy unless the contrary is dktinctly ~tqted GRIESS ON A NEW CLASS OF COMPOUNDS converted into sulphate of diazobenzol according to the eqiia- tion-4 4 r A *C,H,N.SH,O + NIIO = C7H,N,.SH,04 -j-2E1,O. Acid sulphate of Sulphate of diazobenzol. aniline. On account of the slight solubility of sulphate of aniline aid in order to avoid employing a large quantity of liquid it becomes necessary to suspend the salt in water and to expose it in this state to the action of nitrous acid.The reaction however is very slow and the salt is only gradually converted into the diazo- compound I found it therefore more convenient to prepare thc sulphate from the nitrate of diazobenzol by treating a concen-trated aqueous solut'iont of the latter with a sufficient quantity of sulphuric acid previously diluted to avoid rise of temperature upon addition. Tbe solution thus obtained is then mixed with tliree times its volume of absolute alcohol and lastly with a sufficient amount of ether which causes the sulphate of diazobenzol together with some water to separate in a layer at the bottom of the vessel the liberated nitric acid together with the excess of sulphuric acid remaining mixed with the supernatant alcohol and ether.This latter is decanted and the solution of the snlphatc (with a yiew to the removal of a further quantity of water) is once more treated with absolute alcohol and reprecipitated by means of ether. The precipitated liquid is then placed in flat dishes over sulphuric acid when it soon solidifies to n magma of white crys- tals. In order to purify these crystals completely they are washed on a filter with a mixture of alcohol and ether which removes any trace of sulphuric and carbolic acids that may have been produced by a partial decomposition of the sulphate of diazo-benzol then dissolved in weak cold alcohol and precipitated by the addition of ether.The crystals are separated without delay from the mother-liquor and dried over sulphuric acid. Sdphate of diazobenzol cry stallises in prisms which readily dissolve in water but are soluble with difliculty in absolute alcohol and insoluble in ether. The aqueous as well as the alcoholic * Ordinary mlphate of aniline containing excem of free sulphuric acid is under-btood by this formula. .t-The crude solution obtained by the action of nitrous acid upon nitra:e of aniline may be employed. CONTAINING NITROGEN ETC. solution is decomposed on boiling with evolution of gas. Exposed to the air this compound attracts moisture very rapidly becomes liquid and gradually decomposes. Heated alone it deflagrates feebly at about 100"C. Hydrobronzute of Diazobenrol C6f14N,,HBr.This compound is prepared by the action of bromine upon diazo-amidobenzol. When an ethereal solution of bromine is gradually added to a rather concentrated solution of the diazo-amido-corn- pound each drop of the bromine-solution is seen to produce a precipitatioii of the hydrobromate of diazobenzol. When no more crystals are formed the precipitate is separated from the mother-liquor washed with ether till quite white and then dried over sulphuric acid. All these operations must be performed as speedily as possible since thenem compound is of a very unstable nature and rapidly decomposes. Should it be found necessary to recrystallise the precipitate it must be dissolved in the least possible quantity of cold alcohol and ether added to the solution till no more precipitation takes place.Hydrobrornate of diazobenzol crystallises in white nacreous scales which like the compound previously described are readily soluble in water less so in alcohol and insoluble in ether. The solution of this' compound is distinguished by a strong acid re-action. Heat friction and pressure cause the crystals of the hydrobromate to explode with the same violence as the nitrate of diazobenzol. Even when in a perfectly dry state this compound can only be kept for a short time without undergoing decomposi- tiou (which is accompanied by the production of a peculiar aromatic odour) the decomposition being complete in a few days. It is formed according to the equation CI,H,,N2 + 6Br = C&I,N,.HBr + C,H,Br,N -k 2HBr.Diazo-amido-Hydrobr0mat.e of Tribromaniline. beuzol. diazobenzol. Tribromanilint; rcmains in the ethereal mother-liquor from which it crystallises on evaporation. It is most likely that by the action of chlorine upon diazo-amidobenxol hydrochlorate of diazobenzol may be obtained. An aqueous solution of this latter cornpound however may also be prepared by treating a solution of the hydrobromate with moist chloride of silver Perbromide of Diaxobenzol C H,N, HBr.Br,. On adding a small quantity of bromine-water to an aqueous solution of the nitrate of diazobenzol a white crystalline precipi- tate of tribromophenylic acid is usually obtained owing to the presence of a small quantity of phenylic acid formed by the spon-taneous decomposition of the nitrate by water.On removing the tribromophenylic acid as quickly as possible by filtration slid on adding a large excess of bromine-water containing free liydrobromic acid to the filtrate the new bromine-compound separates as a brownish-red oil which solidifies to a crystalline mass soon after the supernatant liquor has been removed. The crystals are obtained pure for analysis by washing with a little ether. Perbromide of diazobenzol which crystallises in yellow plates is insoluble in water rather difficultly soluble in alcohol and in-soluble in ether. It is comparatively stable when dry. Its alcoholic solution on the other hand rapidly decomposes even in the cold with evolution of gas.For this reason it is irnpossi- ble to recrystallise it without loss. In order to purify this unstable perbromide it is most advantageous to dissolve it in cold alcohol and to allow the solvent to evaporate spontaneously in shallow vessels in the open air. Very fine crystals are usually obtained in this manner but contaminated with trifling quantities of an oily product of decomposition which however may be removed by mashing with a little cold ether. On application of heat this com- pound deflagrates at a comparatively low temperature. The con-stitution of the perbromide of diazobenzol appears to be the same as that of periodide of tetrethylammoaium and similar compounds of other bases. Platinum-salt of Hgdrochlorate of Diaxobenzol C,H,N,.HCl.PtCl, is obtained by the addition of bicliloride of platinum to a rather concentrated aqueous solution of the nitrate of diazobenzol.The fine yellow prisms which are precipitated are almost insoluble in alcohol and ether. They are rather stable; when kept for some time however they acquire a bromish colour and arc grndnal!y hut completely decomposed. Ou heating they deflagrate ;Iicnce it it is impossible to estimate the platinum by simple ignition. Gold-sali of Hydrochlorate of Diazobenxol C6H,N,HC1,AuCl3. By the addition of terchloride of gold to a dilute aqueous solu-tion of the nitrate of diazobenxol this compound is obtained in the form of a light-yellow crystalline precipitate insoluble in water but soluble in alcohol especially when warm from which on cooling it is deposited in the form of’ small golden-yellow plates.This salt cannot hom.ever be recrystallized without some loss especially when the alcoholic solution is heated to bciling. The decomposition is indicated invariably by an evolution of gas ; contirmed boiling with alcohol destroys it completely It is well known that when bromine chlorine or hyponitric acid is substituted in organic compounds for certain hydrogen atoms the product formed is distinguished from the original com- pound if the latter be an acid by stronger acid properties or if a base by less pronoixnced basic characters; and also that the con-trary is observed in the case of substitution of potassium NH, &c. for the same hydrogen-atoms. Nitrogen however exhibits in this respect a peculiar double nature since it is found only slightly (or not at all) to affect the basic properties of a compound whilst at the same time it exerts so decided an acidulating action as to impart to strong bases an acid nature.I have already clearly shown that diazobenzol has all the characters of an organic base capable like aniline of forming saline compounds with acids. It possesses at the same time the property of combining with metallic hydrates playing to a certain extent the part of an acid. These metallic derivatives are as a rule distinguished by the same instability as the corn- pounds of diazobenzol with acids. They are less affected horn-ever by heat. Their aqueous or alcoholic solutions can be heated to boiling for some time without suffering complete decomposition.Heated alone they explode although at a much higher tempera- ture and not with so great violence as the bodies previously rte-scribed. The compounds which are soluble in water are mostly well crystallised whilst the insoluble ones such as those formed with silver and lead are obtained as amorphous piwil)itates GRIESS ON A NEW CLASS OF COMPOUNDS Compound of Hydrate of Potassium with Diaxobenxol C,H,N,. KHO. By introducing a very concentrated solution of nitrate of diazo-benzol into an excess of an equally concentrated solution of caustic potash drop by drop a yellowish liquid is obtained possessing a peculiar aromatic odour and solidifying by evaporation in the water-bath to a crystalline mass.This is a mixture of the com-pound of hydrate of potassium with diazobenzol and nitre to-gether with a brownish-red amorphous body-the result of a secondary reaction which a portion of the original substance undergoes aud which is always indicated by the evolution of gas. In order to separate these bodies it is necessary to remove the excess of caustic potash. This is best done by putting the crys- talline mass into a strong linen cloth and squeezing it powerfully between porous stones. The dry cake is then treated with abso- lute alcohol which readily dissolves the compound of hydrate of potassium with diazobenzol leaving the nitrate of potassium in- soluble; it is then separated by filtration. The alcoholic filtrate (which on account of the above-mentioned secondary product of decomposition possesses an intense reddish-brown colour) is then evaporated on the*water-bath.The residue is once moTe pressed and washed with a mixture of alcohol and ether to remove the reddish-brown substance ;the compound is then obtained nearly white. By again pressing aad dissolving the dry cake in a small quantity of absolute alcohol filtering and adding a sufficient amount of ether the substance is obtained in white plates which must be dried at once over sulphuric acid. The compound of hydrate of potassium with diazobenzol crys-tallises in small white soft plates which become reddish by ex- posure to the air; they are very readily soluble in water and alcohol but insoluble in ether.The solution has a strong alkaline reaction. A freshly prepared aqueous solution is hut slightly coloured; but by keeping for a short time it rapidly acquires a yellow colour and ultimately a reddish-yellow substance is preci-pitated. Ebullition does not seem to accelerate this decomposition materially. The dry substance is very stable and cm be kept a long time unchanged Heated alone it explodes at n little above 130";the explosion is accompanied by a slight report. CONTAINING NITROGEN ETC Compound of Hydrate of Silver with Diasobenxol C,H,N,.AgHO. This is obtained as a white or slightly chocolate-coloured pre- cipitate by treating a freshly prepared solution of the previous compound with a solution of nitrate of silver. After removing the mother-liquor the precipitate is thoroughly washed with water dried by pressing between filter-paper and finally over sulphuric .-acid.The compound of hydrate of ailver with diazobenzol is insoluble in all the ordinary neutral solvents. Nitric acid even when cold dissolves it with great facility. It is distinguished by great sta- bility; for even after having been kept for weeks not the least sign of decomposition could be discovered. Exposed to a higher temperature it explodes with some violence. Compound of Hydrate of Barium with Diaxobenrol. This compound is obtained when a solution of a very soluble barium-salt is added to a rather concentrated solution of the potas- sium-compound. It is precipitated in the form of white rnicro- scopic indistinct needles or plates which become yellowish in consequence of a gradual decomposition.It is difficultly soluble in water. The compound of diazobenzol with hydrate of zinc is a white amorphous powder insoluble in water. The compound with hydrate of lead is also a white powder but acquiring rapidly a yellow colour. With sulphate of copper a brown precipitate changing to green is obtained. Mercuric chloride gives a white precipitate. Diaxobenxol C,H,N,. This remarkable substance is obtained when an aqueous mlu-tion of the compound of hydrate of potassium with diazobenzol is treated with a sufficient quantity of acetic acid. A thick yellow oil it liberated which possesses a peculiar odour and is remarkable for its extraordinary instability.Its existence is very ephemeral and after a short time nitrogen gas begins to be evolved and the oil is rapidly converted into a brownish-red substance. The heat which is produced when larger quantities of the oil undergo this spontaneous decomposition is sufficient to give rise to dangerous explosions The addition of ether to the oil dissolves it instantaneously producing a red solution a tumultuous evolution of gas taking place. It combines with nitric and sulphuric acids and vith hydrate of potassa terchloride of gold &c. forming the com-pounds previously described. COMPOUNDS WITH BASES, OF DIAZOBENZOL ORGANIC Diazo-amidobenzol as is well known is formed by the action of nitrous acid upon an alcoholic solution of aniline according to the equation f2CGHYN + NHO = C12H,,N3 + 2H,O.Aniline. Diazo-amid obenzol . By viewing this body as a double compound of diazobenzol and aniline I mas led to prepare it by the direct action of aniline upon COM-pounds of diazobenzol. This reaction proceeds readily on mixing an aqueous solution of nitrate of diazobenzol with aniline when a viscid yellow mass is speedily produced which becomes crystdline after a short time and can be obtained in a perfectly pure state by several recrystallisatioid from alcohol. The formation of the diazo-amidobcnzolmay be expressed as follows :-C6H,N2.NI-I0 -I 2C,H7N = Cl2H1,N3+ C,H,N.NH03. Nitrate of diazobenzol. Aniline. Diazo-amidobenzol. Nitrate of aniline. On referring to the equation given on page 39 for the formation of nitrate of diazobenzol from diazo-amidobenzol it is seen that these two bodies may be readily transformed into one another.LMauy other bases deport themselves with nitrate of diazobenzol exactly like aniline and we may therefore look forward to the dis--sF Any cxccs~of anilinc must be rcrnwcd Eg n?e;lns of acetic =id kefore crysk?A!-lisation. CONTAINING NlTROGEN~ ETC. covery of a large number of double compounds analogous to diazo-amidobenzol. It is not my intention to give a full history of these compounds as a few short statements will shorn clearly how closely they are allied to their prototype diazo-amidobenzol. Diaxobenzol-amidobronobe~~zol,C6H6BrN]. {c6H4N2 This compound is obtained by the action of hromaniline upon riitrate of diazobenzol.It crystallises in very fine small yellow plates or needles which are rather difficultly soluble in alcohol but readily soluble in ether. Its platinum-salt is obtained as a buff-coloured precipitate consisting of fine hair- like crystals. Nitrate of silver produces in an alcoholic solution a yellow precipitate similar to that of the compound previously described. In the formation of the above bodies two atoms of base enter into chemical action with one atom of nitrate of diazobenzol forming together with the diazo-amido-campound the nitrate of the base employed. Naphtalidine (amidonaphtol) however com- bines directly in equal numbers of atoms with nitrate of diaso-beuzol giving rise to a compound which has the formula and which as will be shown must be viewed as nitrate of diazo-benzol-amidonaphtol = This compound is ob-333)NHO,.10 9 tained in an impure state as a violet crystalline precipitate on adding an aqueous solution of nitrate of diazobenzol to an alco-holic solutiori of naphtalidine. It is purified by repeated washings with cold alcohol and recrystallisation from the same forming beautiful green prisms. Its formation takes place according to the equation C6H4N2NH03f C,,H,N = Cl6H14N403. Xitrate of diazo-Naphtalidine. Nitrate of diazo-henzol. benzol-amidonaphtol. YOL. ss €? GRIESB ON A NEW CLASS OF COMPOUKDS lt is one of the finest bodies of which chemistry can lionst. It crystallises in well-defined prisms which by reflected light are of a magnificent grass-green colour but ruby-red Lg transmitted light.The crystals are almost insoluble in water and ether Hot alcohol dissolves them freely and redeposits them almost entirely on cooling. DiaxobeikxoZ-amidonu~htoI 10 9 This compound is obtained from the previous substance by removing the nitric acid by means of ammonia or potnssa. It crystallises in very brilliant ruby-red prisms readily soluble in alcohol and ether forming yellow liquids. Acids impart a beauti-ful violet colour to these solutions. Bichloride of platinum pro-duces a purple-blue crystalline precipitate ; nitrate of dyer it yellow precipitate which consists of small fine needles. It is worth mentioning that these diazobenzol-arnido-compounds can also be obtained by acting with an aqueous solution of the salts of the respective bases upon the compound of hydrate of potassium with diaxobenzol.The reaction which takea place may be expteaaed by the following equation :-C6€I,N,KH0 + C,H,NHCl = C,,H,,N + KC1 + H,O. Hydrate of potasaitim Hydrochlorate Diazo-amido-with diazobenzol. of aniline. benzol. COMPOUNDS DIAZOBENZOL AMIDO-ACIDS. OF WITH Amido-acids are likewise capable of entering into combination with diazobenzol. One mould have expected that the compounds to which this reaction gives rise would deport themselves in an analogous manner to the sulphate or nitrate of diaeobenzd which like the salts of organic bases are capable of double decomposition. This however is not the case.The compounds of diazobenzol with amido-acids behave more like simple bodies exhibiting much similarity to the diazo-amidobenzol being capable like the latter of forming with bichloride of platinum double compourids of the nature of the potassio-biciiloride of platinum. They possess moreover the property of combining with metals giving rise to bodies which correspond entirely to the salts of simple acids. CONTATMING NITROGEN ETC. DicrxobenxoI-*ami dobenzoic acid c,II,NO,o This cornpoiind is obtained by simply aixing an aqueow solution of the nitrxte of diazobenzol (1 molecule) with a solution of amido-benzoic aciJ (2 molecules). It separates as a yellow crystalline precipitate vi:ich is readily freed from the mother-liquor rid when dry dissolved in ether and filtered.The ethereal solution deposits on evapomtion yellow crystals which are obtained piire for analysis by washii;g with cold alcohol. This body is fomcd according to the equation C6H,N2.NH0 -I-?,C,H,NO = C,,HllN,02 + C,H,NO,.NHO,. Nitrate of diazo- Amidobenzoic Diazobenzol-amido-Nitrate of amidoben-benzol. acid. benzoic acid. zoic acid. DiazQbenzol-.nmidobenzoic acid forms small indistinct plates or crystalline grains. It is almost; insoluble in wzter very difficultly sduble in alcohol and easily soluble in ether. Solutions of ammonia potash or cnrbonatc of potassiiiin dissolve the acid readily the solution acquiring a yclkm colonr. On heating a little of the substance on platinum-foil it fuses aid is rapidly decomposed tlic decomposition being accompanied by a violent evolution of gas.Cold dilute mineral acids act upon it but slowly; on heating howemr speedy dccomyosition ensues. Acetic acid even when highly concentrated has no action is the cold but the appli-cation of heat destroys it. Platinum-salt of the Hydrochlorate of D-iazoben~oZ-asnidob~nnoic Acid C 3H N,02.2HC1.2PtC1,. This ccmpound forms small yellowish-white indistinct; plates and is obtained by adding an alcoholic solution of bicldoride of platinum to the ethereal solution of the diazobenzol-Rmido’senzoic acid. Diazobeuzo~-arnidobenzoicacid in its behaviour with bases is similar to a bibasic acid sincr it combines with metallic bodies in two ways. All the salts formed at*ecomparatively stable ;tlmse for example which are solnble in water 2i.s t!ic potassium-salt will eve& bcar recrystallisation.Vith the oxide of silver and barium it GRTESB ON A NEW CLASS OF COMPOUXDS forms insoluble precipitates. A more minute description of t1:ese compounds I must defer to a future time. Compounds analogous to diazobenzol-arnidobenzoic acid arc formed when amido-dracjlic acid [isoamidobenzoic acid) amiclo -anisic acid &c. are made to react in the manner previously de-scribed upon nitrate of diazobenzol. It is my intention to investi- gate these compounds more specially and I therefore abstain from entering further upon their description only noticing that they possess a remarkable resemblance to diazobenzol-amidobenzoic acid.CONPOUNDS IMIDOGEN OF DLAZOBENZOL. By this name are designated a peculiar class of diazobenzol-compounds obtained by the action of ammonia ethylamine and analogous organic bases upon perbromide of diazobenzol (C4€14N2. HBr.Br2). All the compounds hitlierto described exist in the solid state and none of them can be volatilised without decomposition ; the new compounds to be described on the other hand are liquids which can be distilled and which possess the narcotic odour of some vegetable bases such as conidine and nicotine. Beyond this odour however they have nothing in commou with these natural bases. They are indifferent bodies combining with neither acids nor bases. Diazobenxolimide C,H,N = (C6H4:2)’’} N. On treating perbromide of diazobenzol with aqueous ammonia a speedy decomposition ensues with evolution of much heat.The products of the reaction are first bromide of ammonium mhicli passes into solution ; secondly diazobenzolimicle IVhich separates as a heavy oil rather highly coloured by n brown substance simul- taneously produced in small quantity. By repeatedly distilling the oil with water it is obtained perfectly pure and of a slightly yellowish colour ; the substance which imparts to it the intense brownish colour not being volatile is left behind in the retort. The purified oil is separated from the water by a separating filnnel placed over chloride of calcium and then distilled once more from a water-lath in vacuo. Its formation is explained by- the following eqiiation :- COKTAINIXG NITROGEN ETC.HI + 3911,~r. C6H,N,.HGr.Bi* + 4XH = C&',N,7 l'erbromide. Diazobenzolimide. Diazobenzolimide is remarkable for its narcotic aromatic-ammo- iiiacal odoui.. It is volatilised by distillation with water and also when heated in oacuo as shown above. TTlieu distilled at the orcli-nary atmospheric pressure it decomposes with explosive violeuce. Alcohol and ether dissolve it with soine difficulty. I could not sue- ceeci in solidifying the oil by using a frigorific mixture of nitre and sal-ammoniac. Hydrochloric acid even when concentrated and aqueous potassa have no effect upon it. Strong nitric and sul-phnric acids dissolve it with decomposition. This body is obtained in a manner exactly similar to the one employed for the preparation of diazobenzolimide viz.by acting with ethylamine upon the perbromide of diazobenaol It is like-wise a yellowish-coloured d having a deceptive resemblance to the previously described compound. PRODUCT^ OF DECOMPOSITION OF THE DIAZOBENZOL-COMPOUNDS. The transformations which the molecule of diazobeuzol under- goes through the influence of various reagents are numerous and there is probably no other body to be met with in the large field of organic chemistry that surpasses it in this respect. The pro- ducts of decomposition to which it gives rise frequently possess new and very distinctive features ;more frequently however they belong to the benzol or phenyl group in which latter case their formation depends upon the great inclination which the two nitrogen-atoms of the diaaobenzol exhibit to escape and to cedc their place to other atomic groups of the same value (HH).Deportment of Diaxobenxo2-cornpounds when boi Zed in aia aqueozts solution. The transformation of nitrate of diazobenzol under the in-fiiience of boiling water has already been noticed. A similar 5-11 GRIESS ON A NEW CLASS OF comoums change is observed with regard to its sulpliate and hydrobroinate as will be seen from thc following equations :-C6H,N,.SH,0 + H20 = C61160 + SH,O + N,. Sulphate of Phenylic diazobenxol. acid. c6H,N,.HBr + H,O = C6H60 + HBr + N,. Hydrobromate Plienylic of diazobenzol. acid. On the other hand the compounds of diazobeiizol with metallic hydrates exhibit a very different deportment with boiling water.B,V neutralizing the mctal however with a mineral acid the de- composition takes place in accordanee with the above equations. Action of Alcohol upon Nitrate of Diuxobenzol By gradually and cautiously introducing the nitrate of diwzo- benzol into a moderate quantity of alcohol (previously warmed to about 50" C. in order to accelerate tlie solution) and submit- ting the whole to distillation in a water-bath a yellow residue remains which solidifies to a crystalline mass on cooling and dis-solves readily in alkaline solutions whence it mas inferred that it had the character of an acid. There was in fact no difficulty in ascertaining that this body was ncthiiig else than dinitrophenylic acid possessing dl the well -pronounced properties of this com-pound; and to prove this most conclusively it nns converted into the characteristic amidonitrophenylic acid.Dinitrophenylic acid however is not the only product to which this reaction gives rise; for on mixing the distillate with water an oily body separates which collects upon the liquid especially when its specific gravity has been increascd by the addition of R solution of chloride of sodium. This oil may be remaved by means of a separating funnel and dried over chloride of calcium. It possesses when rectified by distillation all the properties of ordinary bcmzol. have converted it into dinitrobenzol by the action of fuming nitric acid and have found this latter identical with that prepared from coal-tarbenzol.The fusing-point of the dinitrobenzol was in both instances 89' C. The production of dinitrocarbolic acid and of benzol can be expressed by the following equation :-2(C6H4N2NH03) I-CZH60 = CGH4(NO,&O + C&&j + C,&O + hT4 + H-0. Nitrate of dineo-Alcohol. Dinitrophenylic Benzol. Aldehyde. benzol. acid. CONTAlNINO NITROGEN ETC. Sulphate of diazobenzol when distilled with alcohol is acted upon in a similar manner. The alcoholic distillate contains the benzol whilst the residue in the flask consists of sulphuric acid and a small quantity of an organic acid. Deportment of Nitric Acid und Nitrute of Dia.;obexol. Ordinary nitric acid as well as the fuming acid has no action upon this compouud in the cold.The diazo-compound was dissolved in the strongest fuming nitric acid allowed to stand for one hour and cautiously diluted with water so as to prevent any rise of temperature; solution of terchloride of gold was then added which gave au immediate precipitate. Analysis showed this precipitate to be identical with the gold-salt of hydrochlorate of diazobenzol. On boiling the solution of nitrate of diazobenzol in fuming nitric acid trinitrophenylic acid is produced. By employing a somewhat weaker acid an admixture of tri- and di-nitrophenylic acid is obtained. Action of Sutphzlric Acid tipon Sulphutt! of Diaxobennol. On dissolving the sulphate in a small quantity of concentrated sulphuric acid and heating in a water-bath a copious evolution of nitrogen gas ensues and a brownish-coloured liquid remains con-sisting of a mixture of the excess of acid employed and a new snlpho-acid.The separation of the two acids is readily accom-plished by preparing their barium-salts. After diluting the brownish liquid with a sufficient quantity of water and adding car- bonate of barium as long as the solution exhibits an acid reaction the insoluble sulphate of barium may be separated by filtration from the barium-salt of the new sulpho-acid. The filtrate is evaporated till a pellicle forms when on cooling a large quantity of crystals of t?ie barium-salt of the new sulpho-acid appears. After separating the crystals by filtration and then cvapornting the mother-liquor further and cooling a new quantity of crystals is obtained.A single recrystallisation from water renders them perfectly pure. This salt forms fine white well-developed prisms attaining frequently to the length of half an inch when the solu-tion is allowed to cool. very slowly. The crystals are readily so!uble in hot rather di6cdtly in coid water and almost insoluble GRIESS ON A NEW CLASS OF CO&lPOUNI)S iu alcohol and ether. The solutions have a neutral reaction. The substance was dried at 160' C.; and on analysis gave numbers which agree with the formula The salt dried over sulphuric acid contained 34 atoms of water of crystallisation which escaped entirely at 130"C. In accordance with 'the analysis of the barium-salt the free acid must be expressed by the formula C6H8S208,and I propose to call it disu@hophenyZenic acid since it may be viewed as a cornpound of two molecules of sulphuric acid with the hypothetical hydro- cnrbaii CcH (plieaylene) viz.C6H,S,H,0,. Its formation may be thus expressed :-C&I,N2.SH,O4 + SH20 = C6H4S2H,0 4-N,. Sulphate of diaaobenzol. Diaulphophenylenic acid. The free acid is easily prepared by dissolviiig the barium-salt in water carefully precipitating the barium with sulphuric acid and concentrating the filtrate on a water-bath till it acquires a syrupy consistency ; when placed over sulphuric acid it crystallises out in the form of warty crystals which are exceedingly soluble in water and alcohol and deliquesce in a moist atmosphere. Besides the compound just described there exists yet another barium-compound of disulphophenylenic acid of the composition C6H,S,Ba,H0, formed by the exchange of a third equivalent of the hydrogen for barium.It is obtained by digesting either the barium-compound with two atoms of barium or the free disulpho- phenylenic acid with baryta-water for some time. The excess of baryta is neutralized by carbonic acid and the filtrate evaporated till it begins to crystallise. The new salt forms very thin white plates which on being left for some time in contact with the mother-liquor are likewise comer t ed into well- formed prisms. This salt differs moreover from the salt containing only two equivalents of barium by its greater solubility in water,* and the strong alkalinity of its solutions which is not destroyed by the carbonic acid.When freshly prepared the crystals of this com-* On preparing the salt CSH4S1H3Ba308, a0 described above with excem of car-bonate of barium a certsin amount of the second barium-compound is formed which rcmains in the mother-liquor from \rhic!i tfic first salt liiis cr,ystaliised. CONTAINING NlTROGEN ETC. pound are clear and transparent; they soon however lose a portion of their water of crystallisation and are reduced to a white powder. It is possible that two more barium-salts of disulphophenyle-nic acid exist having the respective formulz C6H,S2BaH,0 and C6H4S,Ba,0,. Disulphophenylenic acid is likewise capable of combining in two proportions with other metals; with lead it seems to combine even more freely forming apparently no fewer than five distinct salts viz.C6H4S2H,Pb0, C6H,S,H,Pb20, C6H4S2HPb,0, C6g4S,Pb40, and C6H4S,Pb0,.Pb20. The description of the preparation and properties of these bodies will be reserved for a future communication. The silver- salt of disulphophenyleriic acid may however find a place here since it exhibits the peculiar chemical department of the new acid in a striking manner. Disulphophenylenate of Silver is obtained by treating an aqueous solution of the free acid with carbonate of silver evaporating the filtrate first on the water-bath and lastly over sulphuric acid It crystallises either in warty masses or in small plates. It is easily soluble in water difficultly so in alcohol and almost inso- luble in ether.It does not contain any water of crystallisation. After drying over siilphixric acid it does not lose weight even when heated to upwards of 160" C. To judge from the composition of the silver-salt of disulpho- phenylenic acid it appears to be bibasic (C6H4S2H20,),whilst the formula deduced from its barium arid lead salts establishes its tetrabasic character (C6H4S2H,0,). The new acid exhibits there- fore the rare property of varying basicity such a,s is possessed by phosphoric acid in the inorganic and by terebinic acid in organic chemistry as shown by Ekrnau.* Action of Sulphuretted Hydrogm upon the Gold-salt of Hydrochlorafeof Diazobenxol. By passing a current of sulphuretted hydrogen gas through cold water in which the gold-salt has been suspended all the gold is converted into the trisulphide whilst the diazobenzol is trans- formed into a volatile product.When the reaction is complete * Limpricht Lehrbuch der Chemie p. 1016. VOL. sx. F 58 GRIESS ON A NEW CLASS OF COMPOUXDS the liquid is submitted to distillation when a very nauseous heavy yellowish oil is found to pass over with the aqueous vapoar. 1 have not pursued its examination further than to convince myself that it is not the phenylmercaptan (C6H6S) described by Vogt which at first sight it appeared to be. Its mercaptanic odour and its derivation from the diazobenzol in the gold-compound (according to the equation rendered this view very probable. Neitheie basic acetate of lead however nor nitrate of silver even in presence of ammonia gave precipitates with the oil which proved convincingly that it differed entirely from phenylmercaptan.On examining the residue in the retort after the oil has been distilled off it was found to consist of tersulphide of gold and an aqueous liquid; the latter is found to contain chloride of ammonium together with a little free hydrochloric acid and a small quantity of the hydrochlorate of a base which is no other than anilinc. The occurrence of these bodies shows that a mall portion of the diazobenzol is decomposed as follows :-The same products of decomposition are met with when an alcoholic solution of the gold-salt is treated with sulphnretted hydrogen. On passing the latter however over the dry gold-compound it speedily causes an explosion.By employing only a very small quantity of the substance and by spreading it in a thin layer in a glass tube it is possible to avoid explosion and secure a quiet decomposition. The reaction is over when no more hydrochloric acid fumes escape with the current of sulphuretted hydrogen. The black residue which is left behind in the glass tube appears to contain besides tersulphide of gold free diazobenzol. I was not able to isolate the latter. The explosive nature of the residue and its deportment with ether which speedily produces a rapid evolution of gas leave however little doubt of its presence. Hydrochloric acid tersulphide of gold and diazohenzol are there- fore the products of decomposition of the gold-salt by means of sulphuretted hydrogen CONTAINING NITROGEN ETC* Action of Nascent Hydrogen upon DiaxobenzoZimide.If hydrogen is generated by means of zinc and sulphuric acid in an alcoholic solution of this body a point is reached in a com-paratively short time when on the addition of water no more turbidity occurs indicating that the diazobenzolirnide has COM-gletely disappeared. By removing the excess of zinc and evaporating the alcohol on a water-bath the residue when treated with potassa evolves much ammonia-an oily base simultaneously separates ; this is purified by distillation aud is found to be identical with ordinary aniline. The decomposition may be thus expressed :-C6H,N + 8H = C6H,N + 2NH,.Diazobenzolimide. Aniline. Action of Curbonate of Barium upon Nitrate of Diazobenzol. Bp treating a cold aqueous solution of this salt with levigated carbonate of barium a feeble evolution of gas is observed which lasts for several days. A reddish-brown mass is produced insoluble in water which remains with the excess of carbonate of barium when the reaction is over. The residue is a mixture of two dis- tinct bodies. By filtering off the solution containing nitrate of barium and removing the excess of carbonate by means of dilute hydrochloric acid these two products can be readily separated by treatment with cold alcohol in which they are very unequally soluble. In order to obtain the more soluble one in a pure state the alcohol is evaporated and the residue treated with ammonia.An intensely yellow-coloured solution is produced which must be filtered to remove a small quantity of a resinous substance and decomposed with hydrochloric acid when the new compound is precipitated in crystals. These are obtained perfectly pure for analysis by repeated crystallisation from weak alcohol. The formation of this compound may be expressed by the fol-lowing equation :-2(C6H,N,.NH0,) + N,O = C,,H,,N,O + 2NH0 + N,. Nitrate of diazobenzol Hew compound. FfL GRIESS ON A NEW CLASS OF COMPOUNDS It will be readily seen that this formula contains the elements of phenylic acid and diazobenzol* C6H4N2+ C,H,O = Cl2Hl0N2O. I mill therefore call it phenol-diasobenzol without prejudging its rational constitution.This body usually crpstallises from alcohol arid ether (in which it is very easily soluble) in brittle brownish-yellow warts. It is almost insoluble in cold water slightly so in boiling water from which on cooling it crystallises in small yet well-formed rhombic prisms of a fine yellow coIour with a tinge of violet. These crystals fuse at 148 -150' C. to n brownish-yellow oil which cannot be volatilised without decom- position and is destroyed at a higher temperature with formation of yellow vapour. A1 though phenol-diazobenzol has the properties of an acid forming with certain metals saline compounds its acid character is so slightly pronounced that it is not even capable of decomposing carbonates. On evaporating a solution of phenol-diazoberizol with aqueous carbonate of potassium to complete dryness the former mill he left behind unaltered.On evaporating it with aqueous ammonii the whole of the ammonia is driven off. Treated with nitrate of silver it yields a scarlet-red silver precipitate which appears specially snited for determining the atomic weight of this compound. It deserves mention that phenol-diazobenzol is isomeric with azoxybenzide. The pro- perties just described show conclusively however that it has nothing in common with the latter compound beyond the forM ula. The second product of the above-mentioned reaction may usually be obtained perfectly pure by recrystallising it once or twice from strong alcohol afterwards dissolving it in ether aad allowing the solution to evaporate spontaneously.Sometimes however the crystals are slightly contaminated with traces of a body which has to be removed by means of caustic potassa,? in Q Witrosoethyline recently described by Geuther and Kreutzhage will pro- bably come under the same class of compounds since its composition may be expressed by the addition of the hypothetical diazohydride of ethyl and alcohol vi z. C,HJ3" + CzHGO = CAHIJ!l,O. + Instead of treating the mixture of the crude products of decomposition and car-bonate of barium wilh hydrochloric acid in order to remove the Iatter the new compounds may be extracted with potassa then precipitated with hydrochloric acid and lastly separated a8 already described by means of alcohol. CONTAINING NITROGEN ETC.which the new compound is completely soluble whilst the foreign substance remains behind as a brown resin. Hydrochloric acid precipitates it from the alkaline solution and it can now be com- pletely purified by crystallisation from alcohol or ether. Its formation is explained by the equation 3(C6H,N,.NH0,) + H,O = C18H,,N40 + N + 3NH0,. Nitrate of diazobenzol. New compound. It may likewise be viewed as composed of phenol and diazo- benzol viz. and I Would therefore propose the name phenol-bidiaxobenzol. This new cornpound crystallises in brownish-red needles or plates; it is readily soluble in ether difficultly soluble in cold alcohol. Hot water dissolves it but very slightly. When heated it deports itself like the compound previously described.It melts at 131O C. Phenol-bidiazobenzol is an almost perfectly neutral body. Its deportment with potassa (in which it dissolves readily forming a ruby-red solution) reminds one however of the pro-perties of an acid. Ammonia-water dissolves it with difficulty and aqueous carbonate of potassa not at all. Dilute acids exert like- wise no solvent action ; concentrated acids however dissolve it with a blood-red colour. Decomposition ensues when the latter solutions are heated. Action of Potassa upon Nitrate of DiasoBenzol. On mixing diluted aqueous solutions of these two bodies," a yellow liquid is obtained which possesses a peculiar aromatic odour and soon begins to evolve nitrogen gas a reddish-brown neutral substance being simultaneously formed.At the common temperature this reaction is very slow and requires several weeks to be completed. If however heat is employed the decomposition proceeds rapidly and the reddish-brown substance is separated as a resinous semifluid mass quite insoluble in water and only very * The compound of hydrate of potassium and diazobenzol (page 46) does not seem to be furmed in this case as I was able to separate this substance only when very concentrated solutiona of the nitrate ol diazobenzol and potma had been em- ployed in its preparation. GRIESS ON A hfEW CLASS OF COMPOUNDS slightly soluble even in boiling alcohol. Ether dissolves it readily. I have not been able to obtain this substance in crystals. By allowing its ethereal solution to evaporate spontaneously it is left behind in a resinous state.As a powder it is very electric. Boiling with nitric acid produces a new yellowish crystalline body. In order to purify the amorphous product of decomposition I have first washed it thoroughly with water then boiled it with alcohol and finally dissolved it in ether ; the substance remaining after the evaporation of the ether was submitted to analysis. The numbers obtained agree best with the formula The formation of this substance may be expressed by the follow-ing equation :-4(C,H,N,.NHO,) + H20 = + 4-0 + N6. If instead of an aqueous an alcoholic solution of potassa be added to the nitrate of diazobenxol dissolved in water the reaction which takes place is much more complicated.In this case in addition to the reddish-brown body two volatile substances are formed viz. benzol and phenyl C12H10, the hydrocarbon recently discovered by Fittig.* When the reaction is conducted in a retort and heat is applied the benzol passes over with the alco- hol and may be separated from it bp the addition of water. The phenyl being less volatile is obtained after the whole of the alcohol has distilled over ; it condenses to a crystalline mass in the receiver Repeated recrystallisations from alcohol render it quite pure in white plates resembling naphthaline and fusible at 70°C. These properties leave no doubt as to its identity with the phenyl of Dr. Fit ti g to whoin I am indebted for a small portion of his substance which resembles in every respect the body obtained as mentioned above.The third product of the decomposition in question viz. the amorpbous brown substance is left behind in the retort as a resinous mass. From the foregoing observations it will be seen that potassa in the presence of alcohol causes simultaneously three different Jf Ann. Ch. Pharm. cxxi 363. CONTAINING XIT&OGEN ETC. decompositions of the diazobenzol-molecule which may he ex-pressed as follows :-T. CBH,N + C2H60 = C6H6 + C2H,0 + N,. Diazobenzol. Alcohol. Benzol. Aldehyde. 11. f2C6H4N2+ C,H60 = CI2H, + C,H40 + N,. Phenyl. 111. 4C6H4N + H20 = C,,H,,N,O + N,. Reddish-brown substance. Action of Ammonia upon Aqueous Nitrate of Diaxob.enxo1. On adding diluted ammonia to an aqueous solution of this diazo- compound a similar reaction takes place as when the potassa is employed.On treating the brown rnaFs however with alcohol it becomes evident that it consists of two bodies. The difficultly soluble porticn is identical with the nitrogenous body previously described as was proved by analysis. The body accompanying it which is readily soluble in alcohol is obtained by repeated crystallisation in the form of small light-yellow plates which detonate on heating and whose alcoholic solution gives precipitates with nitrate of silver and bichioride of platinum. This compound is in fact no other than the diazo-amidobenzol previously mentioned. The coincidence with this latter was so complete that it appeared to me loss of time to analyse it.With regard to the first of the two products of decomposition it is clear that its formation must be expressed by the same equation which illustrated the reaction with caustic potassa upon nitrate of diazobenzol whilst the formation of the latter (the diazo-amidobenzol) is explained by assuming that a portion of the original compound is decomposed in the following manner :-2(C6H,N,.NH0,) + 3NH = C12H,,N + N + 2NH,NO,. Nitrate of diazobenzol. Diazo-amidobenzol. Two atoms of nitrogen in two equivalents of diazobenzol have therefore been simply replaced by one of ammonia. d4 GRTESS ON A NEW CLASS OF COMPOUNDS Decomposition of the Platiwm-salt of Diaaobenzol and of the Per-bromide of Diaxobenzol by the action of heat.When speaking of the platinnm-salt I had occasion to mention that it detonates when heated. By mixing it however with a large excess of perfectly dry carbonate of sodium,* and heating the whole in a retort on a sand-bath it is quietly decomposed. The decomposition begins at a moderate heat and is marked at first by evolution of gas and subsequently by the distillation of an oily body. The residue in the retort consists of carbonate of sodium metallic platinum and chloride of sodium. The oily distillate contains chlorine. It is obtained perfectly pure by dis- tilling once with chloride of calcium and forms an almost colour- less oil which is heavier than water and has the odour of berizol. These properties as well as the chlorine determination prove that it is chlorobenzol C,H,Clt.The formation of chlorobenzol may be eapreased by the follow- ing equation :-C6fI,N2.Hc1.PtC12 = C6H,Cl + Pt +c1 + N,. Platinum-salt. Chlorobenzol. The platinum-salt of the bromide of diabenzolt is decomposed in an exactly similar manner. The resulting bromobenzol diEers in no way from the bromobenzol obtained by Couper by the action of bromine upon berizol as may easily be shown by converting it into nitrobromobenzol which possesses all the properties of nitro-bromobenzol prepared from coal-tar oil Bromobenzol can also be produced by the decomposition of per- bromide of diazobenzol by heat according to the equation C6H,N,.HBr.Br = C6H,Br + N + Br,. Perbromide of diazobenzol. Bromobenzol.In order to decompose larger quantities of the perbromide of diazobenzol in this manner it is likewise reqnisite to mix it first * It is mlf-evident that other carbon,ates such aa carbonate of barium calcium &c. max be used instead of carbonate of sodium. + In all probability it is identical with chlorobenzol obtained from benzol or phenol. 5 This compound is obtained as an insoluble reddish-yellow precipitate on mixing bibromide of platinum with an aqueous solution of nitrat,e of diazobenzol. CONTAINING NITROGEN ETC. with a sufficient quantity of carbonate of sodium to avoid a vio-lent explosion. By heating the mixture in a retort bromobenzol is obtained almost p"erfect1y pure. The perbromide when heated with alcohol likewise gives rise to a decomposition in accordance with the pre- vious equations.Bromobenzol separates as a heavy oil on the addition of water to the alcoholic solution. It deserves to be mentioned that all these reactions arevery well defined arid that the ammnt of the products of decomposi-tion corresponds allmost theoretically with the quantities em-ployed. APPENDIX. It may be of some interest to mention an experiment I made to obtain ethylated diazobenzo! compounds. For this purpose I submitted nitrate of ethylaniline to the same reaction which pro- duced from nitrate of adine the nitrate of diazobenzol. I ob-tained a body crystdlising like the latter in long needles. If this body had really been nitrate of ethgldiazobenzol I should have expected to obtain by boiling with water a reaction accord- ing to the equation- C,H,(C,H,)N,.NHO + H20 = C,H,(C,H,)O .+ NHO + N, Nitrate of ethyldazobenzol.Ethylyhenjlic acid. It soon became evident however that the oily body produced was nothing else than ordinary phenylic acid; and since no other organic product of decomposition could be traced I had to come to the conclusion that the above-mentioned crystals were nothing else than ordinary nitrate of diazobenzol. In order to decide this question the gold-salt was prepared and after purifying it by recrystallisation from alcohol the well-knowa golden brilliant crystals were obtained which gave on analysis numbers leading to the formula C6H9N2.HC1.AuCl, The action of nitrous acid upon nitrate of ethylaniline may therefore be expressed by the equation- CGH6(C,H,)N.NH0,+NH02 = C6H,N2.NHL),+ C2H60+ H,O.Nitrate of ethylaniline. Nitrate of diazobenzol. Alcohol. GRIESS ON A NEW CLASS OF COMPOUNDS PARTV. The peculiar and somewhat remarkable properties of the corn. pounds derived from aniline in the manner previously described have induced me to try whether bromaniline nitraniline &c. when similarly treated would be converted into the corresponding substituted diazobenzols. This I have succeeded in doing and the new substances thus obtained exhibited all the properties which I found so cliaracter-istic of the normal diazobenzol-compounds. They are if anything more stable owing if I may so express myself to the compara- tively larger amount of solid and stable materials combined with the extremely volatile and easily disturbed nitrogen.This pro-perty renders them better adapted for many experiments in which the non-substituted diazobenzol-compounds are liable to give rise to dangerous accidents. They are likewise remarkable for great beauty. 2\r;trate of Diazobrornobenzol C6H3BrN,.NH03. This compound may be prepared by the action of nitrous acid gas either upon nitrate of bromaniline or upon diazo-amidobromo- benzol and in an exactly similar manner to the nitrate of tliazo-benzol. If an aqueous solution of nitrateof bromaniline be em-ployed nitrous acid gas must be passed through very rapidly at first or else diazo-amidobromobenzol (even in the presence of much free nitric acid) begins to separate.This it is very difficult to convert into the desired compound in an aqueous solution. Nitrate of diazobromobenzol remaining comparatively constant in aqueous solutions it is possible to concentrate them without any great loss by spontaneous evaporation in the open air before precipitating with alcohol and ether. It can be obtained per- fectly pure by repeatedly dissolving in alcohol and precipitating vith ether when it is obtained in the form of purely white scales which mhep crystallising out rapidly present themselves in the form of regular rhombic plates. These crystals like those of nitrate of diazobenzol are exceedingly soluble in water difficultly so in strong alcohol and almost insoluble in ether. They explode when heated struck or compressed though not so readily nor with the same violence as the nitrate of diazobenzol and they CONTAININU NITROGEN ETC.1 can therefore be mixed without danger with oxide of copper and burnt in the usual mode of organic analysis. The formation of nitrate of diazobromobenzol may be repre-sented by the following equations :-I. C,H,BrN.NHO + HNO = C6H,BrN,.NH03 + 2H20. Nitrate of bromaniline. Nitrate of diazobromobenzol. 11. Cl,H9Br,N -k HNO +2NH0,=2(C6H3BrK2.NH0,) +2II,O. Diazoamidobromobenzol. Nitrate of diazobromobenzol. Sulphate of Diaxobromobmxot C6H3BrN2.SH,0,. The preparation of this compound from nitrate of diazobromo-benzol and sulphuric acid corresponds so closely with that of the non-substituted (abromous) sulphate that it may suffice simply to refer to the description already given of the preparation of the latter and I will therefore restrict myself to a few remarks on its properties.Sulphate of diazobromobenzol crystallises in very fine colourless prisms which are very soluble in water very difficultly soluble in alcohol and almost insoluble in ether. The new body is com-paratively stable and can be crystallised from water without suffering the least decomposition by alIowing its solution to evaporate over sulphuric acid. Boiling water decomposes the compound and heat causes it to explode. Hydrobrornate of Diarobromobenxol C,H,BrN,.HBr. This compound is prepared either Fy decomposing an aqueous solution of the previous salt.by means of a suficient quantity of bromide of bqriurn and spontaneous evaporation of the filtrate or by the action of an ethereal solution of bromine iipon an ethereal solution of diazo-amidobromobenzol. If prepared by this latter method the new compound speedily separates in crystals on account of its insolubility in ether and is obtained pure by filtering off from the mother-liquor and washing the crystals with ether. Its formation may be expressed by the following equation :-C12H9Br,N3 + 4Br = C,I13BrN2.HBr + C6H,Br3N + HBr. Diazoamidobromo-Hydrobromate of diazo-Tribromaniline. benzol. bromobenzol. 68 GBIESS ON A NEW CLASS OF COMPOUNDS The hydrobromate of diazobromobenzol forms pearly white shining scales which dissolve very readily in water; like the hydro- bromate of diazohenzol they are more difficultly soluble in alcohol and quite insoluble in ether.In the dry state it can he preserved a long time without undergoing decomposition. On heating it explodes almost as violently as the corresponding nitrate. By treating an aqueous solution with freshly precipitated chloride of silver the hydrobromate is converted into the hydrochlorate of diazobenzol. Perbromide of Diaxobromobenzol C6H,BrN2.HBr.Br2. By treating an aqueous solution* of any one of the previously- described diazobromobenzol-compounds with excess of bromine-water a crystalline orange precipitate speedily falls increasing rapidly till all the diazobromobenzol has been precipitated. If too much bromine has been added the precipitate becomes gelrerally of an oily consistency solidifying however to a yellow crystalline mass as soon as the mother-liquor has been removed and the excess of bromine allowed to evaporate spontaneously.In order to obtain the perbromide thus prepared in fine crystals it is dissolved in the smallest possible quantity of warm not boiling alcohol from which it separates on cooling in yellow monoclinic prisms. A small portioii only remains in the alcoholic mother- liquor from which evaporation rarely recovers it since it usually undergoes decomposition. It will however be seldom necessary to run this risk of losing part of the substance by recrystallisation for the compound is almost perfectly pure from the very first and at all events quite fit to be employed for the experiments to be described further on.Under certain circumstances this perbromide is formed during the preparation of hydrobromate of diazobromobenzol from diazo-aniidobromobenzol in which case the two compounds are readily separated from one another by washing with cold water. Per-bromide of diazobromobenzol crystallises as already remarked in orange monoclinic prisms insoluble in water freely soluble in warm difficultly so in cold alcohol and very difficultly soluble in cold ether. On boiling an alcoholic solution decomposition ensues and on ii The cnide aqueous solution obtained by the action of nitrous acid npon the nitrate of bromaniline may conveniently be employed. CORTAININQ NITROGEN ETC.heating the crystals alone they explode feebly with disengagement of bromine vapour and nitrogen gas. Platinum-salt of the Hydrochlorafe of Diazobromobenrol C6H,Brllri ,.HCl.PtCI,. Bichloride of platinum even from a very dilute solution of the nitrate or sulphate of diazobromobenzol separates a mass of small yellow crystals which appear under the microscope as fractured plates and which are almost insoluh1.e in every neutral solvent. They are stable at 100"C. Gold-salt of the HydrochZorate of Diaxobromobenzol C6H3BrN,. HCl.AuC1,. This compound is precipitated from an aqueous solution of nitrate of diazobromobenzol on the addition of terchloride of gold at first as a yellow oil which however rapidly solidifies to a crys-talline mass.The crystals are insoluble in water but can be recrystallised from warm alcohol without much loss and are thus obtained in the form of splendid small golden-yellow shining plates. Compound of Hydrute of Potassium with Diazobromobenzol C6H3BrN,. KHO. On the addition of caustic potash to a concentrated solution of nitrate of diazobromobenzol a lemon-yellowish precipitate of diazo-bromobenzol separates at first but redissolves in excess of potash. On evaporation by means of a water-bath the solution solidifies when sufficiently concentrated to a reddish-coloured crystalliue paste of nitre and the new compound of hydrate of potassium and diazobromobenzol. The latter is separated and purified exactly in the same manner to the analogous compound of diazobenzol.It differs from this compound in being precipitated from its alcoholic solution by means of ether as a white gelatinous mass and not in the form of crystals. White plates are obtaiiied by allowing its aqueous solu-tion to evaporate on a watch-glass over sulphuric acid which however turn red on keeping owing to a partial decomposition. GRIESS ON A NEW CLASS OF COMPOUNDS Compound of Hydrate of Silver with Diazobromobenzol C6H,BrN,.AgH0. This body is obtained as an almost white insoluble precipitate very similar to the hydrate of silver with diazobenzol. I abstain from describing any more of the compounds of diazobromobenzol with metallic hydrates since they entirely resemble the correspond- ing diazobenzol-compounds in every respect Diazobromobenzol C6H,RrN, is obtained in slender bright-yellow needles by adding weak acetic acid to the compound of hydrate of potassium with diazobromo- benzol or as a bright yellow amorphous precipitate on the addition of dilute potassa to the aqueous solution of the nitrate of diazo-bromobenzol.In either case it is necessary to remove it speedily from the mother-liquor and dry it rapidly over sulphuric acid Diazobromobenzol is an exceedingly dangerous compound ; for the slightest pressure or even touch with a rough object causes it to go off in a fiery explosion almost exceeding in violence that of the nitrate of diazobenzol. Although much more stable than diazobenzol it can be kept only for a short time in a per-fectly unchanged condition.After being kept for some time a reddish-brown residue is left which no longer explodes even on heating and it seems that the nitrogen has been gradually elimi- nated. Ether dissolves diazobromobenzol and causes a violent evolution of gas frequently of such intensity as to give rise to ex-plosions. When freshly prepared this body is soluble in caustic potassa as well as in mineral acids with formation of the previously- described saline bodies. COMPOUNDS WITH AMIDO-COMPOUNDS. OF DLAZOBROMOBENZOL Diazobromobenzol like diazobenzol can enter into combination with amido-bases and amido-acids. Since however these new bodies possess absolutely no fresh chemical interest but resemble in every respect the amido-compounds of diazobenzol it may suffice to mention a few only as briefly as possible CONTAINING NITBOOEN ETC.separates in yellow needles or small plates when a concentrated aqueous solution of nitrate of diazobromobenzol is treated with an alcoholic solution of bromaniliue. This compound mas obtained by me on a former occasion* by the action of nitrous acid upon alcoholic aniline. It needs no further proof that both methods furnish a product of identical properties. The action of aniline upon nitrate of diazobromobenzol gives rise to diazobromo-amidobenzol which not only has the same empirical composition as the diazobenzol- amidobromobenzol (C,,H,,BrN,) (page 49) but resembles it in every other respect. It would no doubt be of interest to deter-mine whether the two compounds are identical or only isomeric.I must however defer answering this question till a future oppor- tunity Diazobromobenxol-amidobenzoic acid {“CiEfNO + BrN2} This body is obtained as a yellow crystalline precipitate ou mix-ing an aqueous solution of nitrate of diazohromobenzol and amido- benzoic acid according to the equation { %2:2} C6H3BrN2.NH03t 2CjH7N0 = -t C7H7N0,.NH0,. Nitrate of diazobromo- Amidobenzoic Diazobromo-Nitrate of amidoben-benzol. acid. benzol-amido zoic acid. benzol. Recrystallised from ether it forms roundish lumps of small needles or plates. 11 every other respect It is identical with diazobenzol-amidoberizoic acid. IMIDOGEN COMPOUNDS OF DL4ZOBROMOBENZoL. Diazobromobenzolimide (‘tiH,’ H rN2) ”}N. On mixing the yellow crystals of perbromide of diazobromo-benzol with solution of ammonia they are speedily converted into a yellowish oil which after a single distillation with water is ob-tained in an almost colourless condition.This oil is diazobrouio- benzalimide in a perfectly pure state. * Ann. Ch. Pharm. cuxi. 273. BRIESS ON A NEW CLASS OF COMPOUNDS If the temperature of the atmosphere be not too-high the oil usually solidifies after a short time. If this does not take place artificial cold must be resorted to The new compound is obtained for analysis by removing the water and drying over sulphuric acid. Its formation is expressed by the following equation :-C6H3BrNZHBr+ 4NI1 - 'GHSBr;2}N + 3NH,Br. Perbromide. Diazobromobenzolimide.Diazobromobenzolimide presents itself generally as a white or slightly yellowish mass of small crystalline plates which melt at about 20' C. to a heavy oil. It is insoluble in water rather diffi-cultly soluble in alcohol and easily soluble in ether and benzol. It distils readily in the presence of water ;heated alone it explodes feebly. Left exposed to the open air it appears gradually to volatilise giviag off the same aromatic ammoniacal odour which characterises diazobenzolimide. It resembles the latter moreover in its behaviour with various reagents ; caustic potassa hydro-chloric acid and bromine have no action upon it strong siilphuric and nitric acids decompose it readily. By the action of ethylamine aniline &c. upon perbromide of diazobromobeuzol corresponding substitution-compounds of diazo-bromobenzolimide are obtained.Ethyldiazohromobenzolimide (c6''3B6:iL} N forms a yel-lowish oil which does not solidify even when cooled much below oo c. PhenyIdiazobromobenxolimide (C6H3B>?$i} N is obtained in the form of orange crystals. REMARKS OF THE COMPOUNDS ON THE PRODUCTS OF DECOMPOSITION OF DIAZOBROMOBENZOL. The great similarity existing between the properties of the diazobromobenzol-compounds and those of the corresponding abromous bodies ia likewise encountered in their products of de-composition ohtained under similar circumstances ; and I have thercfore generally abstained from verifying the latter by analysis CONTAINING NITROGEN ETC. having restricted myself to bringing forward analytical numbers in a few cases only.On heating an aqueous solution of nitrate or hgdrobromate of diazobromobenzol an evolution of nitrogen gas takes place bromo- phenylic acid (which separates as a brownish oil of the odour of creosote) being simultaneously produced. C6H,BrN,.HBr + H,O = C6H,Br0 -t HBr + N,. Hydrobromate of diazo-Bromop henylic bromobenzol. acid. Ebullition of nitrate of diazsbromobenzol with alcohol gives rise to the formation of bromobenzol which distils over with the vapour of alcohol a yeliow acid (probably bromodinitrophenylic) being left behind. Ammonia forms a yellow body with simultaneous production of diazo-amidobromobenzol which owing to its greater solubility in alcohol can be readily separated from the former.The formation of diazo-amidobromobenzol takes place according to the formula 2C6H,BrN2 + NH = C,,H,Br2N3 + N,. Diazobromobenzol. Diazo-amidobromobenzol. Sulphate of diazobromobenzol when heated with sulphuric acid is converted into a sulpho-acid which is most probably di- sulphobromophenylenic acid C6H,Br.S,H408. Nascent hydrogen generated by the action of zinc upon sul-phuric acid in presence of an alcoholic solution of bromobenzo-limide converts the latter into bromaniline and ammonia. C6H4BrN3+ 8H = C,H,BrN + 2H,N. Diazobromoben-Bronianiline zolimide. When the addition of water no longer gives rise to a precipitate indicating that the whole of the imide has been decomposed the brornarriline is most easily isolated by evaporating the alcoholic solution on a water-bath and distilling with caustic potassa.Bromaniline then passes over in oily drops which quickly solidify and may be crystallised from alcohol in octahedra. These crys- tals as well as the properties of the platinum-salt prove it to be identical with the ordinary bromaniline. By heating the platinum-salt of diazobenzol with carbonate of VOL. xx 0 GEIESS ON A NEW CLASH OF COMPOUNDS sodium chlorobenzol was obtained; so in like manner by the action of heat ou the platinum-salt of hydrochlorate of diazo-bromobenzol chlorobromobenzol is produced according to the following equation :-C,H,BrN,,HCl,PtCI = C6H4BrC1+ Pt + C1 + N,. Platinum-salt of diazobrorno-Chlorobro-benzol.mobenzol. By pressing the crystals which condense in the neck of the re-tort between filter-paper distilling a second time and crystallising from alcohol they are obtained sufficiently pure for analysis. Chlorobromobenzol is rather difficultly soluble in alcohol readily so in ether and crystallises in white needles or plates from a hot saturated alcoholic solution on cooling or by evaporation of the ethereal solution. The crystals possess a peculiar odour resembling that of benzol. Tbe double salt of dibromide of platinum and hydrobromate of diazobromenzol is obtained in the form of' ruby-red crystals by mixing a tolerably concentrated aqueous solution of the diazo- salt with dibromide of platinum. This cornpound shows as might be expected a similar deportment.Like the preceding platinum- salt it breaks up according to the equation C6H,BrN,.HBr.PtBr = C6H4Br + Br + N + Pt. Platinum-salt of the hydro- Dibromo-bromate of diazobromobenzol. beozol. Dibromobenzol is readily prepared also from the perbromide of diazobromobenzol by heating the latter alone,* or with carbonate of sodium when it is decomposed according to the equation C6H,BrN,HBr = C6H,Br + Br + N,. Perbromide of diazo-Dibromobenzol. bromobenzol. A still more convenient method of' preparing dibromobenzol consists in the decomposition of the perbromide with alcohol which is completed after a few minutes' boiling; and if too much * Only small quantities must be employed in order to prevent riolent explosions. On heating the perbromide in a long-necked flask,the dibromobenzoi condenses in the cold part of the vessel.CONTAINING NITROGEN ETC. alcohol has not been employed a large portion of the dibromobenzol separates at once in the form of crystals The remaining portion is precipitated on the addition of water in the form of a thick oil which soon solidifies to a crystalline mass. After washing with a little alcohol and pressing between bibulous paper this mass together with the crystals first precipitated is subjected to distilla-tion. Dibromobenzol distils over as au almost colourless oil which speedily solidifies. Dibrornobenzol very much resembles chlorobromobenzol in its various physical properties. It ci-jstallises from ether in the form of rectangular prisms or small plates which are frequently very regular.and well formed sometimes however agglomerated in various ways. It melts at 89OC. The properties of the dibromobenzol prepared in the manner just described can leave no doubt that it is identical with the dibromobenzol described by Coil per and obtained by the action of bromine upon benzol. Although large quantities of dibromobenzol can be prepared by Couper's method with perhaps greater facility it is always difficult to obtain the dibromo-compound quite free from tribromo-benzol which is simultaneously formed. The above method might be preferred in all cases when abso-lutely pure dibromobenzd is required as for instance for certain physical purposes-the more so since it invariably yields theo- retical quantities.The same may be said of several other deri- vatives of benzol and its homologues which are obtained from diazo-compounds to be described hereafter. DJAZODIBROMOBENZOL COMPOUNDB. Nitrate of Diazodibromobenzol C6H,Br2N,.NH0,. This compound is readily obtained bf the action of a rapid current of nitrous acid upon an aqueaus solution of nitrate of bromaniline containing free nitric acid. The liquid is allowed to evaporate spontaneously the residue taken up with weak alcohol and the new cornpound precipitated by means of ether. It can be recrystallised without loss from water or alcohol by evaporating the respective solutions below their boiling-points. Its aqueous solution remains remarkably constant. Continued boiling even for hours frequently leaves some of the substance undecornposed.Nitrate of diazodibrornobenzol crystallises in fine white prisms UlL GRIESS ON A NEW CLASS OF COMPOUNDS or elongated hexagonal plates. 3 does not detonate with the same violence as the corresphding bodies proviously described. Perbromide of Biazodibrornobenzol C6H2Br,N2.HBr,. This compound is formed by the addition of bromine-water to an aqueous solution of the nitrate of tliazodibrornobenzol when it is precipitated in the form of fine long needles. On boiling with alcohol and subsequently adding water an oily substance is thrown down which soon solidifies and can be obtained perfectly pure by pressing the precipitate between bibulous paper then dis- tilling and finally crystallising from alcohol.Thus purified it presents itself in the form of fine long silky needles. This sub- stance is evidently tribromobenzol presenting all the properties of that compound obtained by the distillation of C,H6Br6 with alkalies by L ass ai gn e.* Platinum-salt of the Hydrochlorate of Diaxodibromobenzol. C,H,Br,N,.HCI.PtCI,. It separates in small orange oval plates which are difficultly soluble in water on adding dichloride of platinum to the hydro- chlorate. Diazodibromobenxolimide Is easily obtained iu crystals by mixing the perbromide with ammonia. Repeated recrystallisation from hot alcohol yields it in the form of white needles which melt at 62OC.,and deto- nate slightly at a higher temperature. It is very little soluble in water more soluble in hot alcohol and very readily so in ether.DIAZOCHLOROBENZOL COMPOUNDS Perfect analogy exists between these bodies as well as between the diazodichlorobenzol compounds and the compounds just described with regard not only to the modes of preparation from * Rev. Scient. vol. Y p. 360. CONTAINING NITROGEN ETC. chlorine and dichloroaniline but also in respect to their various physical properties. I therefore abstain from entering into a minute description and will simply enumerate some few experi-ments which I hope will satisfactorily prove their great similarity. Nitrate of Diazochlorobenzol C6H,C1N2.NH0, crystallises in small white plates which on boiling with water yield chlorophenylic acid in the form of a brownish oil possessing the odour of creosote.Perbromide of Bazochtorobsnzol C6H,ClN2.11Br3 forms yellow prisms which are decomposed ia boiling alcohol with formation of bromochlorobenzol the composition of which is thus expressed C6H,C1Br.* Platinum-salt of the Hydrochlorate of Diazochlorobenzol C6H3~1N,.HC1.PtC12 forms fine yellow needles. On heating with carbonate cf sodium it yields dichlorobenzol which is obtained according as it crystal-lises slowly or rapidly in long fine needles or in elongated four-sided plates possessing the same peculiar aromatic odour as the dibrornobenzol. Diu~ochlorobenzolimide,(C6H3CIN2)” N forms readily fusible HI crystals. Diaxochlorobewol, C6H,CIN2 is obtained as a highly explosive lemon-yellow precipitate.DIAZODICHLOROBENZOL COMPOUNDS. flitrate of Diazodichlorobenzol presents itself in the form of white plates. The perbromide C,H2C1,N2 HBr, which is formed by the action of bromine-water crystallises in yellow prisms ; the platinum-salt in small beautiful yellow very brilliant plates DIAZO-IODOBENZOL COMPOUNDS It will suffice to give likewise only a short outline of these * The bromochlorobenzol thug obtained is identical with the body described oq page 74 aa derived from C6H3BrN2.HCl.PtCl2. ORIES8 ON A NEW CLASS OF COMPOUNDS bodies owing to the great resemblance whicli usually exists between them and the cornpounda of diazobrornobenxol both in regard to their preparation and chemical deportment and also with respect to their physical properties Nitrate of Diazo-iodobenzol C,H,TSJ,.NHO, is prepared from nitrate of iodaniline precisely like the corres- ponding bromo-compound and crystallises in white needles or prisms which are exceedingly soluble in water.SUlphafe Of Diazo-iodobenzol C6H,IN2,SH,O,j crystallises in small plates which are easily soluble in wafer diffi-cultly so in alcohol. Pwbromide of Diazo-iodobenxol C6E-I,IN,.HBr, forms small lemonqellow slender plates. On boiling this compound with alcohol it yields bromoiodo-benzol C6H,BrT which crystdlises from ether or alcohol in large white plates volatile without decomposition. Platifiurn-saltof the Hydrochlorate of Diazoiodobenxol C,H,IN,. HCLPtCL, forms small bright yellow clusters of needles.forms yellowish-white crystals which are readily fusible and pass over on distilling with water as a yellowish oil soon solidifying. Thislikewise is of a peculiar aromatic ammoniacal odour. Diazo-iodobenzol C6H,IN2 is obtained as a yellow explosive precipitate. DIAZONITROB~NZOL COMPOUNDS. The remarkable isomerism observed between a and /3 nitraniline and hitherto left unexplained by any chemical theory likewise extends as I have shown upon a former occasion to the double compounds which I have described as 01 and fl diazo-amidonitro-benzol. This isomerism however is somewhat less striking since COXTAINING NITXOGEPU’ E’I’C. these bodies retain sue-half the nitraniline required for their for- mation in the original condition as will be clearly seen on ex-amining the rational formula which I assign to these bodies.The simple diazo-componnds derived from these isomeric nitranilines cannot however be viewed similarly and it was impossible therefore to decide h prz’ori the question of their isomerism. The experiments presently to be described nevertheless leave no doubt that a similar isomerism exists between the several member8 of both series and that although of identical compositiou they exhibit difl‘erences in their physical properties as striking as those observed between the original bases. a Diaxonitrobenzol compounds.* Nitrate of The preparation of this compound by the action of nitrous acid upon a nitraniline is exactly similar to that of the analogous bodies already referred to.By gradually adding ether to its alco- holic solution till crystallisation coLz;mences it is obtained in fine long needles which however do not exhibit any distinct form of crys tallisation. This compound like all the rest of the like bodies is very readily soluble in water more difficultly so in alcohcl insoluble in ether and explodes with the same violence on heating. Perbromde of a Diazonitrobenzol C,H,(NO,)N,.HBr,. On mixing an aqueous solution of the former compound with bromine-water this new body is speedily thrown down in slender orange prisms which are almost insoluble in water and scarcely soluble in ether. They dissolve however readily iu warm alco-hol from which they are deposited on cooling in well-defined crystals.* The a nitraniline employed for these experiments was obtained according to Arppe’s method by the action of alkaline liquids upon nitrated anilides. The /3 nitraniline wasprepared according to Hofmann and Muspratt’s method from dinitrobenzol by the reduction with sulphnretted hydrogen. 0,.NH,)N,0(NH,c 2 benzoDiazonitro GRIESS ON A NEW GUS OF COMPOUPU'DB Platinum-salt of the Hydrochlorale of tr. Diaxonitrobenzol C6H3(N02)N,.HCI.PtC12. On the addition of chloride of platinum to a hot aqueous soh-tion of the hydrochlorate of diazonitrobensol this double salt which crystallises in long yellow needles is precipitated. On recrystallising it from boiling water in which it is soluble (d-though with difficulty) the crystals are obtained as prisms fre- quently very well formed u Diazonitro benzo limide This compound is prepared by the action of ammonia upon Derbromide of a diazonitrobenzol.By repeated recrystallisation A from alcohol it may be obtained in a perfectly pure state in the form of very brilliaut yellow rounded plates which are so soluble in hot alcohol that a magma of crystals separates on cooling from a firaturafed solution. The crystals dissolve as readily in ether. In boiling water they fuse producing a yellow oil but slightly soluble in water ; the portion dissolved yields very fine almost white crystals on cooling. The melting point of the crystals obtained by recrystallisation from alcohol was found to be 71' C. The substance explodes when heated a little above the melting point.@ Diazonitrobenzol compqunds. Nitrate of p Diaxonitrobenaol C6H3(N02)N2.NH0, is obtained from the nitrate of ,l3 nitraniline. The /3 doee not differ much from the corresponding tr. compound in solubility; they however exhibit perceptible differences in the forms of their crystals which in the 18 compound are prisms frequently ap-proaching the cubical form whilst the crystals of the nitrate of a diazonitrobenzol are long needles of a somewhat unpronounced charactep Perbromide of /3 Diazonitrobenzol C6H,(N0,)N,,HBr3. On treating an aqueous solution of the nitrate of p diazonitro-benzol with bromine-water the new cornpourid is thrown down CONTAINING NITROGEN ETC. 8'' generally as an oil which soon solidifies.It forms small plates or prkms of an orange colour which seem to differ from tht. crystals of the a compound by their want of stability when treated with warm alcohol and which I have scarcely ever been able to recrystallize. The perbromide of ,S diazonitrobenzol is also obtained by the action of bromine upon diazo-amidonitro-benzol by suspending tile latter in water and adding bromine till the whole is converted into a heavy brownish-red oil. The suyer- natant aqueow mother-liquor is decanted and the excess of bro-mine allowed to evaporate spontaneously when the oil solidifies to a crystalline mass. Before however cornplete solidification occurs thick yellowish- red prisms are frequently seen to shoot out of about an inch in length which consist of almost pure perbromide containing mere traces of tribromonitranilipe a body which forms in the reaction to nearly the same extent as wit1 be seen from the following equa- tion :-C13H,(N02)pN3-t 8Br = C6H,{No2)N,.HBr3+ C6H,(N02)Br3N+ 2H8r.@ diazoamidotri-p Perbromide. Tribromonitraniline. benzol. The adhering tribromnitraniline* can be removed by washing the finely pulverized crystals with ether in which the perbromide is almost insoluble. If no crgstsls are formed after the bromine has evaporated in the mariner described but only a crystalline mass of perbromide and tribromaniline the latter is pressed betweeu bibulous paper and then washed with ether in order to separate the two com- pounds. This however cannot be done without incurring a con-siderable loss of perbromide since by the action of the ether it is partly coil ver ted into nitrobromobenzol.* In order to obtain the tribromnitraniline in a pure state the ethereal sqlution iq evaporated to dryness,and the residue dissolved by warm alcohol. Water is then added to the alcoholic solution till it hecomes milky and deposits crystals. These are thrown upon a filter and then pressed between sheets of filter paper in order to remove any adhering bromonitrobenxol and purified further by recrystallisation from weak alcohol. Tribromnitraniline crystallizes in small slightly yellowish plates yhich cannot be sublimed withoqt dqcqmposition. GRIESS ON A NEW CLABS OF COMPOUNDS Platinum-sa It of the €€ydrochEorateof p Diaxonitrobenxol C6H,(N0,)N2.HCl.PtC1,.This compound crystallises likewise in needles or prisms resem-bling much the crystals of the a compound. Diazonitrobenzolimide [C6H3(N02)N2g} N differs from the M compound by crystallising invariably in orange- coloured needles which melt at 5Y C. and consequently much below the melting point of the a compound It is likewise somewhat soluble in hot water from which it crystallises on coolingin whitish needles closely resemblirig those of the a diazonitrobenzolimide recrystallised also from hot water. It has sQmewhat of the odour of nitrobenxol. ON THE PRODUCTS OF THE RIAZONITROBEN-OF DECOMPOSITION ZOL COMPOUNDS. These so far as my observations go are decomposed unde'r the influence of reagents like the other diazobenzol compounds ; and their transformations may be expressed by corresponding equa- tions.The nature of their products of decomposition may in fact be safely predicted before-hand as the same isomerism which characterises the compounds already described is observable. It appeared of sufficient interest to trace them somewhat more fully. I could not have given the comparative history of the products of decomposition however without deviating too far from the main direction of this investigation and I must therefore reserve for a future opportunity a more intimate acquaintance with these in- teresting bodies. A few illustrations will show how promising a harvest of interesting results may be expected from such an in-vestigation.One peculiar fact deserves mention here. I had taken it for granted that the same relations would be exhibited between the isomeric diazonitrobenzol compounds and the isomeric acids of the formula C6H,(N0,)0 (the nitrocarbolic acid of Hofrnann and the isonitrocarbolic acid of Fritsche) as that ob-served between the compounds of diazobenzol and carbolic acid and that their deportment would be represented by the equation CONTAINING NITROGEN ETC. C6H3(N02)N2.NH03+ H,O = C6H,(N02)0 + NHO + N2. a-P Nitrate of diazonitro-a-fl Nitrocarbolic benzol. acid. The assumption has not been verified. On boiling these diazo- nitrobenzol compounds with water they are certainly decomposed after some time with evolution of nitrogen gas but neither the a nor 6 compound furnishes under these circumstances either of the well-known phenylic substitutes.In both cases a brownish and easily fusible substance is obtained which readily dissolves in alcohol and ether but can in no manner be made to crys- tallise. I have not ascertained whether this substance deports itself differently according to its origin (from the a or p cornpound) iior have I analysed it; but judging from the progress of its for- mation and also from the weak acid properties it exhibits (dis- solving in potassa and being reprecipitated by hydrochloric acid) I presume that its composition is probably represented by the formula C,H,(~O,)O* On heating an alcoholic solution of the perbromide of a-diazo-nitrobenzol it is readily decomposed according to the equation C6H3(N02)N,.HBr,= C6H4(N0,jBr + N2 + Br,.a perbromide. Bromonitrobenzol. A portion of the bromonitrobenzol formed in this manner sepa- rates in crystals on cooling provided the amount of alcohol em-ployed has not been too large; the rest is precipitated on the additiop of water. The crystals are purified by pressure between filter-paper and distillation when they pass over as a slightly yellowish oil which soon solidifies to a crystalline mass. The bromonitrobenzol thus prepared is diEicultly soluble in cold readily in hot alcohol and ether. It crystallises from these sol- vents in long almost white needles which melt at 126' C. and have the odour of nitrobenzol. If the perbromide of P-diazonitrobenzol is decomposed in a similar manner with boiling alcohol and the solid product of decom- position which forms is purified as described before a compound is obtained to which the formilla C6H4(N0,)Br must likewise be assigned but which differs greatly in its physical appearance and properties from the former bromonitrobenzol.It crystallises from alcohol and ether in which it seems to be more easily soluble $4 GRIESS ON A NEW CLASS OF COMPOUNDS in the form of well-made slightly yellowish or almost white rhombic prisms sometimes also in plates and melts at 56' C. or 70° below the melting point of the bromonitrobenzol derived from the a compound. The existence of these bromonitrobenzols suggests the question whether one of them be not identical with the bromonitrobenzol prepared by Couper by the action of fuming nitric acid upon bromobenzol.Couper's description of this body appeared to me scarcely conclusive of its nature; and in order to decide this question I have treated bromobenzol prepared from coal-tar naphtha with fur6ing nitric acid and have compared the perfectly pure product after repeated recrystallisations from alcohol with the bromonitrobenzolv prepared by my method. The striking co- incidence between the crystalline form of Coup er's compound and of the bromonitrobenzol corresponding to the a-nitraniline which I will now call a-bromonitrobenzol became at once per- ceptible ; and since both compounds crystallise in white needles that could by no means be distinguished from one another I felt justified in corning to the conclusion that both are identical.In order however to make quite sure I have also determined the melting point of the respective compounds and have found it uniformly at 120' C.* They are acted upon in like manner by various reagents. When reduced in alcoholic solutions by sulphide of ammonium they are both converted into bromaniline which crystallises in octahedrons and proves itself to be completely identical with that obtained from bromisatin or bromacetanilide by distillation with potash. Very different from this is the deportment of brornonitro- benzol (6 bromonitrobenzol) prepared from perbromide of 6 diazonitrobenzol. On treating this compound with sulphide of ammonium it is certainly also converted into bromaniline but this base differs greatly from the above-described bromaniline.Ordinary bromaniline (which I would now designate as a brom-aniline) crystallises as is well known in octahedra which melt at 57" C. The new base however (the /3 bromaniline) forms an oil which does not solidify even in winter. The chemical deport- ment of both compounds is the same; they form under like con- ditions a series of derivatives which are of the same composition and differ only in their physical properties. * C o u p e r states (Ann Ch. Phys. [3] lii 309) that his compound melted below 90" C. This is evidently erroneous. CONTAINING NITROGEN ETC. In order to establish the composition of the bromaniline experimentally I have analysed the hydrochlorate and .its pla- hum-salt.The hydrochlorate qf $ bromaniline forms white nacreous brilliant plates which are readily soluble in water and alcohol and are rapidly coloured red when exposed to the air. The Platinum-salt of the Hydrochlorute of $ Bromaniline C,H,HrN.HCl.PtCI, crpstdlises in yellow often well-formed prisms which are far more soluble in water than the slender highly lustrous plates of the platinum-salt of a bromaniline. I need scarcely state that nitrochlorobenzol compounds corres- ponding to CL and $ nitrobromobenzol can readily be obtained by submitting the platinum-salts of a! and @ diaeonitrobenxol to dis- tillation with carbonate of sodium. These two bodies differ like- wise most characteristically ; CI.nitrochlorobenzol crystallises inva- riably in long almost white needles which melt at 83' C. whilst nitrochlorobenzol crystallises from its ethereal solution in thick columns which fuse at 46'C. The former is converted by sulpliide of ammonium into the ordinary (a) chloraniline the latter into a new base (6 chloraniline) which is distinguished by its remaining an oil at the common temperature. The platinum- salt presents itself in the form of yellow crystals which differ like- wise considerably in form and solubility from the small slender plates of the platinurn-salt of 3~ bromaniline. It may I think be safely deduced from these facts that two distinctly different series of compounds are obtained by the substitution of two atoms of hydrogen in benzol by two different elements or groups of atoms according to the manner in which this substitution is accomplished and that these two series differ most distinctly in their physical properties although their chemical composition is the same The great differences between the melting-points form one of the most important means of distinction between the members of the two series.The melting points of series a lie considerably higher than tbose of the series; sometimes a difference of 70" C. is observable as will be seen by the accompanying Table. Bromouitrobenzol ..... . a Series. 126" C. p Series. 56' C. Chloronitrobenzol ...... 83"C. 46" C. Nitraniline . . ....... . 141°C. 108' C. GRIESS ON A NEW CLA.58 OF COMPOUNDS a Series.Seriea. Bromaniline.. .......... 57' C. Liquid at the ordinary temperature. Chloraniline.. .................... Liquid at the ordinary Diazo-amidonitrobenzol .. 245"C. temp erat ur e. 195' C. Diazonitrobenzolirnide .. 71° C. 53O c. The compounds to which the experiments just described gave rise belonged exclusively to the aniline group. Now there could be little doubt that the homologues of aniline and the similarly constituted bases might be also converted into diazo-compounds. This I have confirmed by experiment the more readily since it was to be foreseen that the decomposition of some of these com-pounds would give rise to the formation of certain bodies which could not have been obtained by the ordinary methods e.g. naphtylic alcohol the existence of which however could not be doubted for a moment.DIAZOTOLUOL COMPOUNDS. These compounds exhibit considerable analogy with regard to preparation solubility and many other properties to the corres- ponding aniline derivatives. They seem however to be somewhat more constant and to crystallise more readily. Nitrate of Diaxotoluol C,H6N,.NH0,. This substance is best prepared by the action of nitrous acid upon an aqueous solution of nitrate of toluidine but it can also be obtained from diazo-amidotoluol. It forms long white needles which are decomposed on boiling with water according to the following equation :-C,H6N,.NH0 + H,O = C,H,O + NHO + N,. Nitrate of diazotoluol. Cresyl-alcohol The otlrer compounds are readily obtained from the nitrate in the ordinary manner.&@hate of Diaxotohol C,H6N,.SH,0, is obtained in brilliant needles plates or prisms according to the CONTAINING NITROGEN ETC. circumstances under which it crystallises. On heating; it with sulphuric acid in the manner described when speaking of the sulphate of diaeobenzol it is converted into a sulpho-acid. The barium-salt of this acid crystallises in long white needles and consists of disulphotoluylenate of barium which has the fOPmUla C7H6S,Ba,07. Perbromide of Diaxotoluol C,H 6N2.HBr.Br2 is thrown down as a yellow oil which after evaporation of the excess of bromine solidifies to a crystalline mass. Piatinurn-salt of the Wydrochlorate of Diazotoluot, c,z6N,.HCI.PtCI, is precipitated from a dilute solution of the hydrochlorate of diazo- ioluol by means of bichloride of platinum and forms fine yellow prisms.When ignited with soda it yields an aromatic oil chloro-toluol (C,H,Cl). It remains to be seen whether this oil is iden-tical or only isomeric with the chlorobenzyl discovered by C anizzaro. DiazotoluoI-amidoben~ol,{C7H6N2 ‘GH5 (H,N) is obtained by the action of aniline upon nitrate of diazotoluol. It crystallises in beautiful long yellow needles. DIAZONITRANISOL COMPOUNDS. These compounds are nearly related to the diazonitrobenzol- compounds both with regard to physical properties and their deportment with reagents. They are prepared also in a similar manner and it is only necessary therefore to refer respecting their preparation to these analogous bodies.Nitrate of Diaxonitranisol C,H,(N02)N,0.NH0, is obtained from nitrate of nitranisol. It separates from an alcoholic solution on addition of ether forming small white plates which are dowlg decomposed on heating with water giving rise to the formation of a brownish-red substance. GRIESS ON A NEW CLASS OF COMPOUNDS Perbromide of Diaxonitranisol C,H,(NO,)N,O.HBr, forms small yellow plates Which on boiling with alcobol,. furnish bromonitranisol (C,H,(NO,)Br) crystallising in light-yellow opaque needles which may be sublimed and possesses the odour of nitrobenzol. crystallises in light-yellow needles and has the odour of bitter almonds. Platinum-salt of the Hydrochlorata of Diarmitranisol C7H,QN02)N,O.HCI.PtC1,. When precipitated from a moderately concentrated solution it forms a yellow powder which under the microscope is found to consist of fine needles. Recrystallised from boiling water it is obtained in orange-red well-formed prisms. On heating it with carbonate of sodium chloronitranisol (C H 6( N0,)ClO) distils over which crystallises in fine almost white needles. DIAZONAPHTOL COMPOUNDS. Nitrate of Diazonaphtol C,,H6N2.NH0, is prepared by the action of nitrous acid on moist nitrate of nap-thalidine (amidonapb tol) an amorphous reddish-brown substance* being formed at the same time which must be separated by filtration when the reaction is over. As nitrate of diazonaphtol is not pre- cipitated from its aqueous solution by alcohol and ether it is not so easily obtained in the solid state as the corresponding bodies previously described ; if however its aqueous solution be allowed to evaporate spontaneously in 8 shallow vessel long white needles are formed which are very soluble in water and alcohol and like- wise very explosive.Perbromide of Diazonaphtol C,,H6N,,HBr, is obtained in the form of orange-coloured crystals by the action of bromine-water upon the crude solutioii of the nitrate. # Probably impure nitrate of diazonaphtol-amidonaphtol. COXTAIKING NITROGEN ETC. Platinunz-salt of the Hydrochlorate of Diazonaphtol C,,H6N,.H C.lPtCl, forms truncated yellowish crystals which are almost insoluble in water alcohol and ether Diazonaphtolimide,(C10H6%)''} N passes over as a yellowish-coloured oil (which becomes brown when exposed to the air) by distilling with water the substance obtained by the action of ammonia upon the perbromide.It possesses somewhat the odour of naphtaline. Ol3SERVATIONS ON THE PRODUCTS OF DECOMPOSITION OF THE DIAZONAPHTOL COMPOUNDS. After it had been shown that the products of decomposition of the diazouaphtol compounds so milch resembled those of the other diazo-bodies the intention of pursuing their study in all directions could not be entertained especially since known bodies would frequently have formed the subject of such study. The decomposition of the perbromide for instance by means of alcohol gives rise to the formation of bromonaphtaIine that of the plati- num-salt when ignited with carbonate of sodium to the formation of chlornaphtaline.It was thought however of sufficient im-portance to ascertain whether nitrate of diazonaphtol would split up according to the equation- C,,H6N2"0 + H20 = C,,H,O + N + NHO, since the possibility of obtaining the long-sought-for naphtyl-alcohol presented itself. On boiling the solution of the nitrate of diazonaphtol an immediate evolution of gas takes place and a viscid violet-brown mass separates which remains on the filter when the solution is filtered hot. The filtrate deposits generally small white plates retaining however a portion of the substance dissolved which can be re- covered by shaking the aqueous solution with ether. On evapo-rating the ether it remains behind as a violet-coloured oil which quickly solidifies.This latter as well as the plates first deposited is in fact almost pure naphtyl-alcohol whilst the violet-brown VUL. xx. H GRIESS ON A NEW €?.LAM OF COMPOUNDS mass on the filter contains besides naphtyl-alcohol a considerable quantity of a reddish-brown body. In order to purify the naph- tpl-alcohol the united portions are treated with a cold solution of potassa the residuary brown-red body* is filtered off and the filtrate treated with acetic acid as long as precipitation ensues. Naphtyl-alcohol separates first as an oil soon solidifying to a net- work of small plates which are still somewhat violet-coloured. They are thrown on a filter wasbed with cold water (which re- moves the mother-liquor) and then submitted to distillation.This process must be repeated until the maas of crystals which is invariably found deposited in the condensing-tube is quite white and fuses on heating to a limpid oil. Naphtyl-alcohol crystallises in small white shining plates melting at 91' C. to T. colourless highly refractive oil which may be vola- tilised without decomposition. It is but slightly soluble in water readily soluble in alcohol ether and benzol. When inflamed it burns with a thick smoky flame. Its formation and its physical properties prove its relationship with phenylic alcohol ; it pos-sesses a similar burning taste and a creosote-like odoar some- what resembling that of naphtaline. The relation betwezn it and phenylic alcohol is likewise indicated by its chemical de- portment.It stands on the same narrow boundary line between acid and alcohol; and naphtyl-alcohol may like phenol be classified with alcohols or with acids The strong bases form with the new alcohol (acid) a series of salts which are as unstable as those of phenylic acid and are mostly decomposed even by the cslrbonicacid of the air. The potassium- or sodinm-salt may also be obtained by the action of the respective metals upon the fused naphtylic acid with evolution of hydrogen. In both cases a crys- talline saline mass is obtained which dissolves in water and alco- hol. Basic acetate of lead produces in a solution of naphtyl- alcohol a white voluminous precipitate. An ammoniacal silver solution is decomposed metallic silver being deposited.Nitric acid of sp. gr. 1.4 dissolves naphtyl-alcohol in the cold with evo-lution of red fumes. If the solution be boiled for some time and water added a sparingly soluble yellow acid precipitates whilst a second readily soluble acid is deposited in yellow crystals on evaporating the mother-liquor. The latter appears to he the picric * This body is soluble in alcohol to which it imparts a blood-red colour. On concentrating the alcoholic solution reddish-brown indistinct crystals are deposjted which on rubbing acquire a green metallic lustre. CONTAINING NITBOGEN ETC. acid of the naphtyl group. By treating the aqueous solution of naphtyl-alcohol with bromine-water it deposits bromonaphtylic acid in the form of an oil which speedily crystallises.Many of the experiments described here and in the previous part of this investigation were made in the laboratories of the Royal College of Chemistry London and of the IJniversity of Marburg ; and it gives me great pleasure to express my sincere thanks to Professors Hofmann and Kol be for the kind manuer in which the laboratories of these institutions have been placed at my disposal. PARTVL All the diazo-compounds which have formed the subject of Parts IV. and V. of this inquiry are derived from monoamido-compounds. If the composition of the latter be again expressed by the general formula C,H(+,,(NH,)”O (see page 361 it is at once perceived that the process of formation of the diazo-compounds is similar to the reaction which takes place by the action of nitrous acid on ammonia 11.(NH,)” + NHO = (N2)ft+ 2H,O. Ammonia Nitrogen. By viewing the diamido-compounds in like manner as repre- sented by the general formula C,H(,-4)(NH,),”,0z it is evident that the action of nitrous acid may give rise to two decomposi- tions The hydrogen contained in one atom of ammonia can thus be replaced by nitrogen or both atoms of ammonia present in the * It must be borne in mind that nitrous acid acts upon the nitrate8 of t,he amido-compounds ;if otherwise the reactions would frequentlygive rise to the formation of diazoamido-compoundsformerly described by me. a2 GR,IESS ON A NEW CLASS OF COMPOUNDS original compound may be replaced by nitrogen giving rise to a tetrazo-compouhd.Although this theory has not been fully confirmed by the action (presently to be described) that nitrous acid exerts on benzidine since an intermediate compound according to equation I could not be obtained it is nevertheless highly probable that nitrogc- nous compounds in accordance with equation I exist and that further experiments with other diarnido-compounds will confirm this view. Action of Nitrows Acid upon Benziclisze. Benzidine which Zinin its original discoverer expressed by the formula C,H,N has been found on further investigation by P. W. Bofmann to have double the atomic weight first assigned to it and to be a base capable of coabining with two moleculev of acid.Very recently Fittig has shown that it must be viewed as the diamido-com- pound of his newly discovered hydrocarbon phenyl and that it ought to be expressed by the rational formula C12H8(NHJ2,or C12H6(NH,)”,. I entirely agree with Fittig’s view but find it necessary to select for both compounds a somewhat modified no-menclatnre in order to avoid the use of the same names for some derivatives of these bodies (which I shall have occasion to de-scribe) already employed for several long known derivatives of phenylic acid. I propose therefore to designate Fit t ig’s hpdro- carbon C12H10,as diphenyl and to call benzidine diarnidodi-phenyl. Nitrate of Tetrakodiphenyl C,,H6N,.2NH0,. This compound is most readily and copiously obtained by pass- ing nitrous acid through a cold concentrated aqueous solution of nitrate of diamidobenzidol when only traces of a brown amor-phous body are formed whilst from an alcoholic solution the latter is deposited in considerable quantities When a sufficient current of gas has heen passed through the solution the brown body is separated by filtration the filtrate mixed with twice its volume of strong alcohol and ether added as long as any white crystals are deposited.By once more dissolving the crystals in a very smalk COSTAININB XITROGEN ETC. quantity of water and reprecipitating with alcohol and ether they are obtained perfeotly pure ; it will be readily perceived that this mode of preparation closely resembles that for the prepara- tion of nitrate of diazobenzol which body presents a striking analogy to the nitrate of tetrazodiphenyl.‘Yhc latter crystal- lises in white or slightly yellowish needlee which are readily soluble in water more difficultly so in alcohol and insoluble in ether. On heating they explode with the same violence as the analogous diazo-compound After mixing a cancentrated aqueous solution of the nitrate of tetrazodiphenyl with a sufficient quantity of cold sulphuric acid diluted previously with its own bulk of water this new body separates on the addition of strong alcohol either in the form of a white crystalline powder or in white needles. If alcohol does not completely precipitate it ether must be added to complete its separation. It is very soluble in water.On heating it in the dry state an explosion ensues. Flatinurnsalt of the Hydrochlorate of Tetraxodiphcynl C1,H6N,.2 H Cl.fLPtC1,. This salt is precipitated from a moderately dilute solution of the nitrate or sulphate by means of bicliloride of platinum. It forms light-yellow very small narrow plates. By employing a very dilute solution it is slowly deposited in small elongated well- formed hexagonal plates. These crystals are almost insoluble in water alcohol and ether. Exposure to light during drying causes them to assume a slightly brown colour. Perbromide of Tetrazodiphenyl C1,H6N,.SHBr.Br,. This compound is formed on the addition of bromine-water to an aqueous solution of nitrate of tetrazodiphenyl being precipi- tated in the form of round reddish crystals which are collected on a filter thoroughly washed with water and dried without delay over sulphuric acid and caustic lime.They are thus obtained sufficiently pure for analysis. FurtheP purification indeed is im-possible since this body is decomposed by dissolving in alcohol GRlESS ON 11 NEW CLASS OF COMPOUNDS with evolution of gas. Even at the ordinary temperature it under-goes a gradual decomposition and evolves bromine recognizable by its odour. Tetrarodiphenyl-amidobenzol C H7N {::::} . By adding aniline to an aqueous solution of nitrate of tetrazo-diphenyl this cornplex substance corresponding to the diazo- amidobenzol in the diazobeuzol series is at once separated as a yellow crystalline mass; by repeatedly washing with alcohol it is easily obtained in a pure state for analysis.The formation of this new substance may be expressed as follows :-C,,H6N4.2NH0 -I-4C6H7N =Z C,H,,N6 4-2(C6r17N.NH03). Nitrate of tetrazo-Aniline. Tetrazodiphenyl-Nitrate of aniline. diphenyl. amidobenzol.. Tetrazodiphenyl-amidobenzol is insoluble in water and although very little soluble even in boiling alcohol and ether can be recrystallised from them. By this means lance-shaped crystals are obtained which are generally grouped together in a star-like form. When heated they explode ; boiled with mineral acids they are decomposed with evolution of nitrogen gas This body is obtained in crystds when the perbromide ig acted upon by solution of ammonia. The crystals are purified by re-peated recrystallisation from strong alcohol when they are obtained in small very brilliant white or slightly yellowish plates insoluble in water very difficultly soluble in cold alcohol and only moderately soluble in ether.Boiling alcohol however dissolves them very readily and yields on coolirig a mass of crystals. The compound melts at 127' C. to a yellow oil whioh is decomposed at a higher temperature giving rise to slight explosions. It does not combine with acids or alkalies and is perfectly neutral to test- paper. No change is produced even by boiling with concentrated hydrochloric acid or with aqueona or alcoholic potash. It is decomposed however by nitric or strong sulphuric acid. CONTAINING NITROGEN ETC. The formation of this compound may be expressed by the fol-lowing equation :-cl,H6N,.f2HRr.Br4* + 8NH = C,,H,N,? + GNH,Br.Perhromide. Tetrqodiphenylimide. It has been niy endeavour to study somewhat more closely the compounds whiah tetrazodiphenyl forms with metallic hydrates but all attempts to obtain them more definitely have failed; their preparation seems indeed to be beset with insurmount-able difficulties. I omit a lengthened dtwription of the unsuc-cessful attempts and will merely show by me instance how tetra-zoiliphenyl oan play the part of an acid. An aqueous solution of nitrate of tetrazadiphenyl when mixed with caustic potash yields a yellow liqnid exhibiting such properties as might be looked for in a solution of the compound of hydrate of potassa with tetra-zodiphenyl.On treating it with chloride of platinum it gives rise to the formation of the platinum-compound above described a proof that the tetrazodiphenpl remains unchanged in the alka-line solution. It is invariably decomposed on the application of heat with evolution of gas and separation af a reddish-brown amorphous substawe. PRODUCTS OF THE COMPOUNDS OF DECOMPOSITION OF TETRAZODIPHENYL. By applying the laws of classification now accepted by chemists t o the tetrssotised derivatives of benzidiue specially taking into accopnt their manner of formation and combination these bodies must be classified with the diatomic compounds whilst the respective diazo-compounds belong to the monatomic bodies It has been of late a favourite subject of chemical research to trace the analogies which monatomic bodies exhibit under the influence of certain agents with poljatomic bodies.In illustration of this I may refer to the reaulta obtained in the comparative study of the products of decomposition of the ethyl-and ethylene-alcohols in order to shorn how simple are the laws which regulate these chemical transformations. The experimental results which I am able to adduce pave likewise * Leaving aside the hydrobromic acid this compound may he looked upon the bromide of a tetratomic radical (C19HSNdyBr4. S6 GRIESS ON A NEW 6LAS& OF COMPCIUSDS that the decomposition of the tetrazo-compound gives rise to derivatives which differ in nothing from those obtained under similar circumstances from diazo-compounds beyond the distinc- tive features imparted to them by the polyatomic nature of the compound from which they are derived.Action of Water upon Nitrate of Tetrazod@henyl. An aqueous solution of this body when left in a cold place gradually undergoes spontaneous decomposition. When heated it gives rise to a copious evolution of nitrogen gas with separation of two substances-one an amorphous brown and the other a white crystalline body. An additional quantity of the latter is obtained when the liquid has become quite cold. It is easy to aeparate these two bodies by filtering off the acid mother-liquor pressing the residue between bibulous paper and repeatedly ex-tracting with dilute alcohol which takes up the crystalline sub- stance and leaves the brown body undissolved; this latter being very probably identical with the brown compound obtained as a by-product in the formation of nitrate of tetrazobenzidol and being moreover of a very unpromising nature I have not pursued its study any further.The crystalline product of decoaposition dissolved by the alcohol is obtained on evaporation as a yellowish crystalline mass from which the last traces of’ the brown body are removed by repehtedly dissolving in ether and recrystallising from dilute alcohol. The formation of this compound for which I propose the name of diphenyl-alcohol or diphenyliic acid takes place according to the equation C,,H6N,.2NH03 + 2H20s C,,H,,O + 2NH0 -I-4”. Nitrate of tetmzodiphenyl.Diphenyl-alcohol. Diphenyl-alcohol (diphenylic acid) crystallises in small white or slightly tinged plates or needles which possess slight solubility in water but are soluble to any extent in alcohol and ether. It melts when heated and can be sublimed in small quantities by heating it cautiously in a test-tube. It is thus obtained in the form of soft white very lustrous plates. The chemical deportment of diphenyl- alcohol shows it to be most closely allied to the class of compounds the best-kuown representative of which is phenylic alcohol. It may in fact be considered as the- first biatomic representative of CONTAINIRG NITROGEN ETC. this peculiar group of chemical componnds. The new alcohol is readily soluble in potash and can be reprecipitated by the addition of an acid.Concentrated ammonia also dissolves it. On treating an ammoniacal solution with basic acetate of lead a white volumi- nous precipitate ensues. Heated with ordinary strong nitric acid it is changed into EL nitro-acid which crystallises out in yellow roundish crystals ; the ammonium-salt of this acid crystallises in beautiful long needles. Action of Alcohol upon Sulphate of Tetrazodiphenyl. On heating a mixture of alcohol and sulphate of tetrazodiphenyl violent decomposition takes place. The products formed are nitro- gen sulphuric acid and a solid substance which separates in small indistinct plates on mixing the alcoholic liquid (after the reaction is entirely over) with a large quantity of water. In order to free the precipitate from a trace of a brown substance which likewise forms in the reaction it is filtered off from the mother-liquor dried and then sublimed through paper according to the method proposed by Gorup-Besanez.The snbstance is thus obtained in the form of perfectly white plates which dissolve easily in ether and hot alcohol and crystallise from the latter very much like naphtaline. At 7OoC. it melts yielding an oil which distils at a higher temperature without decomposition. It possesses a peculiar aromatic odour like that of cinnamol and benzol combined. Its chemical composition combined with the before-mentioned physical properties prove that the hydrocarbon is identical with the diphenyl described by Fittig.* Its formation may be de-scribed by the followit~g equation :-2(CizH,N4.3SH20J + 4CpHb0 = 2C12Hi0 + 4CLH*O + N8 + 6SHp04-Sulphate of t,etrazo-Alcohol.Diphenyl. Aldehyde. dipheny1. Nitrate of tetrazodiphenyl is decomposed in a similar manncr by boiling alcohol but simultaneously the formation of a yellow * If the diphenyl prepared according to my method has not been previously sublimed through paper as described it crystallises only in small indistinct silvery- white plates which gre SO different from the large naphtaline-like plates de- scribed by Fittig that they appear at first sight to be crystals of quite a different compound. GRIESS ON A NEW CLASS OF COMPOUND8 nitro-acid takes place which stands probably to diphenylenic alcohol in the same relation as the nitrophenyl to phenylic alcohol (compare also the corresponding decomposition of nitrate of diazo- benzol p.54). Action of Sulphuric Acid upon Sulphate of Tetrazod@henyt. On heating sulphate of tetrazodiphenyl dissolved in a small quantity of oil of vitriol a violent evolution of nitrogen gas is observed The brown liquid which remains after the reaction has ceased contains besides the excess of snlphuric acid employed two new sulpho-acids which can be separated by means of their barium-salts. For this purpose the brown liquid is diluted with at least thirty times its volume of water boiled and saturated with carbonate of barium. The precipitated sulphate of barium is then filtered off the saline solution evaporated to dryness on the water-bath and the residue several 'times extracted with hot water.The portion remaining undissolved is the barium-salt of a new acid which I will call tetrasulphodiphenylenic acid ;the soluble portion contains another new acid for whioh the name trisulpho-diphenylenic acid may be adopted. I mill first erideavour to give a brief description of the former. The barium-salt of this acid obtained as before mentioned being only very slightly soluble in water could not well be pufified by recrystallisation ; I preferred therefore to convert it into the ammonium-salt which served me as a starting-point for the pre- paration of all the saline compounds presently to be described. The ammonium-salt is readily obtained by decomposing the barium-salt with a solution of carbonate of ammonium.The mixture is heated for a short time the insoluble carbonate of barium filtered off and the filtrate concentrated on a water-bath till the ammonium-salt crystallises out on cooling. One recrystal- lisation from alcohol yields it in the form of perfectly pure white prisms Barium-salt of Tefrasulphod@henyleenic Acid C,,HG. S,H,Ba*O 6 On adding chloride of barium to a rather concentrated boiling solution of the ammonium-salt this salt is precipitated in white needles or prisms; the crystals are allowed to subside and after COXTTAINING sITROBEN ETC. the mother-liquor has been separated by filtration repeatedly washed with cold water ; in this manner they are obtained quite pure. Dried over sulphuric acid the salt retains four molecules of water of crystallisation.If the ammonium-salt of tetrasulphophenylenic acid be treated with baryta-water instead of chloride of barium another barium- salt is formed which according to the subjoined barium-determi- nation has the composition C12H6.S4Ba6015. It is precipitated as a white amorphous powder which on washing with water is con- verted into small prisms. Silver-salt C,,H6.S,H3Ag3O1,. On mixing a concentrated solution of the ammonium-salt with an equally concentrated solution af nitrate of silver separation of warty crystals of this salt takes place after some time. They may be purified by recrystallisation from water in which they are easily soluble. The concentratiqn of their soIution must be con- ducted in vacuo.When dried over sulphuric acid it retains three molecules of water of crystallisation which are givcn off at 100' C. When describing disulphophenglenic acid (page 96) it was shown that it is capable of forming two series of salts exhibiting to each other a relationship analogous to that of the metaphosphates and ordinary phosphates. Tetrasulphodiphenylenic acid behaves in a similar manner. Thus the salts previously described point most naturally to the conclusion that it is hexabasic while the salts which will be presently mentioned indicate its capability of assuaing also an octabasic character Lead-saZt Cl,H6.S4Pb,016. When a boiling solution of tetrazodiphenylenate of ammonium is mixed with a solution of neutral acetate of lead this salt is pre-cipitated in the form of white needles.Repeated washings with water render it quite pure. Basic Leadsalt C,,Ei6.S4Pb,016 3. Pb,02. This salt is obtained by treating the hot solution of the ammo- nium-salt with basic acetate of lead. It is a white amorphous precipitate. 100 GRIESS ON A NEW CLASS OF CONPOUNDS Tetrasulphodiphenylenic acid is easily obtained in the free state either by decomposing the lead- or silver-salt with sulphu- retted hydrogen or by treating the barium-salt with an equivalent quantity of sulphuric acid. The filtered aqueous solution is eva- porated on a water-bath to a syrupy consistence and placed over sulphuric acid; after some time white needles or plates are ob-tained which are very soluble in water and alcohol but not deli- quescent in the air.I have not yet analysed this acid; but accord- ing to the above-mentioned salts it seems very probable that it can exist in two different states as expressed by the formulz C,,H~.SSH~O~, and C12136. S$&016. The second compound (trisulphodiphenglenic acid) to which the reaction of sulphuric acid on sulphate of tetrazobenzidol gives rise deserves likewise a few passing remarks. The separation of its barium-salt from the barium-salt of tetrasulphodiphenylic acid by means of hot water has already been described. The aqueous extracts thus obtained when sufficiently evaporated and allowed to cool will generally solidifv to a gelatinous mass from which no dis- tinct crystals can be obtained even hy repeated solution and evapo- ration.Crystallisation may however be eil'ected thus The gela-tiaous salt is converted into the ammonia-compound by boiling with an aqueous solution of carbonate of ammonium. The excess of ammonia is removed by evaporation and ttie crystalline residue dissolved in a little hot water and treated with a solution of chlo- ride of barium. On cooling warty crystals or globular groups of small plates of the barium-salt are obtained which can be freed from the difficultly-soluble tetrasulphodiphenylate of barinm with which it may still be contaminated and also from the mother- liquor by repeated crystallisation from water. White amorphous precipitate obtained by treating a hot solution of the barium-salt with a solution of neutral acetate of lead.Precipitated from a solution of the ammonium- or barium-salt with basic acetate of lead. It scarcely differs in its properties from the previous salt. CONTAINIRQ NITROGEN ETC. Trisulphodiphenylenic Acid. is obtained in the free state in exactly the same manner as tetra- sulphodiphenyle'niciic acid which it resembles in every other retipect. It is evident at aglance that its cornposition may also be expressed in two different ways viz. C,,H6.S,II,0,, or C,,H6.S3H6012. In accordance with the experiment jiist described the decom- position which tetrazodiphenyl undergoes by the action of sul-phuric acid may be expressed by the following equations :-I. Cl,H6N -I-S,H,O, = C12H6S4H8016 4-N4.Tetrmodiphenyl. Tetrasulphodiphen ylenic acid. 11. C1,H6N4 + S,H60, = C,,H6.S3H,01 + N,. Tetrazodiph enyl Trisulphodiphenylenic acid. Decomposition of the Platinum-salt of Tetrazodipphenyl and of the Perbromide. On mixing the platinum-salt of tetraaodiphenyl with from four to six times its weight of carbonate of sodium and heating tlie mixture Cn a retort a copious evolution of gas speedily ensues; and on increasing the heat an oily body distils which solidifies in the neck of the retort to a white mass. By pressing this body between bibulous paper and repeated recrystallisation from boiling alcohol it is obtained perfectly pure. Its composition is C,,H,Cl, and its formation takes place thus t-C,,H6N4.2HC1.2PtCl = C,,H,CI2 + el + Pt + N4.Platinum-salt. New body. This new body which I will call dichlorodipheny! crystallises in white usually wellAformed prisms ; it is difficult of solution even in boiling alcohol but readily soluble in ether and quite insoluble in water. It melts at 148"C. to a yellowish oil which can be dia-tilled without decomposition. On heating in like manner the perbromide of tetrazodiphenyl with carbonate of sodium a mixture of bromine and nitrogen gas is evolved and on heating more strongly an oily substance distils over which quickly solidifies It is obtained pure for analysis by repeated recry sta11isation from ether. FRANKLAND AND DUPPA'S This compound which may be called dibromodiphenyl resem-bles the previously described chlorine-corn pound ; it crystallises likewise in a-ell-formed prisms which appear to be even more in-soluble in alcohol and ether than the above and melt at 164' C.This substance is obtained moreover by boiling the perbromide with alcohol a13in the following equation :-C,,H6N,.H,Br,.Br = CI2H,Rr + N4+ Br,. Perbromide. Dibromodiphenyl. The substance separates from the alcoholic solution on cooling in crystals; it is best purified by distillation. Dr. Fittig informs me that he obtained a cornpmnd of like composition by acting with bromine upon diphenpl. The descrip-tion of this new componnd given by him applies so entirely to the dibromodiphenyl prepared by me thnt no doubt remains of the identity of the bodies obtained by the two methods.