摘要:

FltAXKLhNUj ON ORGANO-METALLIC BODIES. 172 XIX.-On Organo-metallic Bodies. A Biscourse delivered to the MemFiers of the Chemical Society of London BY DR. E. FRA4NKLAND F.R.S. ALTHOUGH organo-metallic bodies as a distinct class of organic compounds are with one exception the creation of the last ten years yet the derivatives of these bodies have been known for a much longer period. From the time that an organic acid was first united with a metallic base these organic compounds containing metals date their existence. It is true that such compounds con- taining a metallic constituent have not bcen regarded from this point of view; but a little consideration will serve to show that they stand in the same relation to organo-metallic bodies in the strict sense of the term as the ethers alcohols acids and numerous other organic families occupy with regard to the alcohol-radicals from which they are derived.Thus zinc-ethyl yields by oxidation ethylate of zinc ZnC,H + 0 = ZnO,C,H,O Zinc-ethyl. Ethylate of zinc. a body which although unknown until formed by this reaction has undoubted and well-known analogies in the ethylates of potash and soda. By suitable processes of oxidation ethylate of zinc may be con- verted into acetate of zinc. ZnO,C,H,O + 0 = C,H,ZnO -i-E,O Ethylate of zinc. Acetate of zinc. The ethyl-compounds of potassium and sodium also pass through analogous phases of Oxidation. Again potassium-ethyl and sodium-ethyl under the influence of carbonic acid yield the propionates of potash and soda II;C,H + C,O = CGH,ICO Potassium-e thy I.Propionate of potash. NaC,H + C,O = C,f-E,NaO -* Sodium-ethyl. Propionate of soda. VOL. XIXI. N 178 FRANKLAND ON ORGANO-METALLIC BODIES. The same result may also probably be reached by two distinct stages viz. first by the conversion of potassium-ethyl and sodium-ethyl into the ethylates of potash and soda KC,H + C4H,0 KO Potassium-ethyl. Ethylate of potash. and secondly by the action of carbonic oxide upon these bodies C,H,KO + C,O = C,H,KO Ethylate of potash. Propionate of potash. The second stage of this conversion has not yet been experi- mentally realized but Berthelot's ingenious production of formiate of potash from carbonic oxide and hydrate of potash exhibits an homologous reaction.These examples serve to point out the relations existing between organo-metallic bodies in the usual acceptation of the term and that far more numerous elass of derivatives to which the same name might without impropriety be applied; and it is now only necessary to remark that the present discourse will be confined to the consideration of organo-metallic bodies in the usual and more restrieted sense of the term. Formation of Organo-metallic Bodies Organo-metallic bodies admit of being produced by a great variety of processes; but these numerous methods of formation with very few exceptions admit of being grouped under four heads. 1. Formation by union of the oyganic radical in statu nascenti with the metal.TJpon this method depends the production of zinc-ethyl the reaction being usually expressed by the following equation Iodide of ethyl. Zinc-ethyl. It is however very doubtfnl mhether this equation correctly expresses the actual change which occurs in the production of zinc-ethyl. It has long been known that this body is found in a free state in very small quantity only amongst the products of the FRANKLAND ON ORGANO-METALLIC BODIES. reaction of zinc upon iodide of ethyl but that there exists amongst these products a crystalline body which contains zinc ethyl and iodine and which may be regarded as formed according to the equation Iodide of ethyl. Ethiodide of zinc. This compound is decomposed at about 150' C yielding iodide of zinc and zincethyl Ethiodide of zinc.Zincethyl. Contemporaneously with the first of the above reactions there occw others in which ethyl hydride of ethyl and ethylene are produced. The separation of ethyl in this reaction is doubtless due to the direct action of zinc upon iodide of ethyl Iodide of ethyl. Ethyl. whilst the appearance of the secondary products ethylene and hydride of ethyl results from the action of the ethiodide of zinc upon iodide of ethyl Ethiodide of zinc. Iodide of ethyl. Hydride of ehtyl. Ethylene. a view which is supported by the behaviow. of sodium-ethyl in contact with iodide of ethyl.* 2C4H5' = 2C,€f4 + 2'4%) + ZKI I< {cjr+ Ii CH Potassium-ethyI. Iodide of ethyl. Ethylene. Hydride of ethyl. Notwithstanding the intermediate stage just indicated in the production of zinc-ethyl the final result of the reaction is correctly expressed in the first of the above equations.* Proceedings of Royal SOC. vol. ix p. 345. NfZ 180 PRANKLAND ON ORGANO-METALLIC BODIES. Zinc-methyl and zinc-amyl are produced in a perfectly analogous manner but no attempt has yet been made to form the corre- sponding compounds of the remaining alcohol -radicals. The hame method of formation yields cadmium-ethyl," when iodide of ethyl is digest& with cadmium at a teingcrature of from looo to 150" C. Iodide of ethyl. Cadmium-ethyl. In this case also there appears to be an intermediate stage in the process probably quite analogous to that noticed in the production of zinc-ethyl.The temperatwe at which the ethiodide of cadmium thus formed is decomposed (177O C.) is considerably higher than that required for the decomposition of the corresponding zinc -cornpound in consequence of which a small proportion only of cadmium-ethyl is obtained the remainder being broken up into other products This circninstance has hitherto prevented the complete inves-tigation of cadmium-ethyl. The experiments of Wanltl yn how-ever scarcely permit its existence to be doubted. No other organo-cadmium cornpoimds have been formed. Treated with iodide of ethyl magnesium gives magnesium ethyZ,t the reaction commencing briskly at ordinary temperatures but requiring a heat of 120° C to 13Q0C for its completion ______~ Iodide of ethyl.Magnesium-eth yl. The honiologous reacticn with iodide of iricthyl appears also to yield magnesiztm-methy1.S Similarly treated aluminum yields at temperatures from 100' to 130' C aluminium-ethyl and aZzcnzinium-metly~.§ 3',7) i-Al = (A12 *Wnnlrlyn Chcm. SOC. +Cahours Aim. Ch. Phjs. [3] hii 17. FHANKLABD ON ORGANO-METALLIC BODIES 181 Double compounds of aluminium-ethyl and aluminium-methy 1 with the iodide of aluminium are here formed and the orgaiio-aluminium bodies have not yet been obtained with certainty free from iodide of aluminium. GZucinunz-ethyl* appears also to be formed under similar cir- cumstances hut its existence has not yet been confirmed by analysis. Orgnno-compounds of Tin.-Although these bodies can be obtained by other processes the general method we are noxv considering is doubtless the most convenient mode of producing most of them.Tin is capable of forming three distinct classes of binary inorganic compounds which may be represented by the following general forinulz Sn R sn2{:R i:t R This threefold atomic character of the metal tin renders the result of its action upon the iodides of the alcohol-radicals con- siderably less simple than those we have hitherto considered. Without taking into account compounds to which a still more complex constitution has been assigned the existence of the following series of orgxno-metallic bodies containing tin has been cstablisfied :j- 1st Series. 2nd Series. 3rd Series. R+ R+ R+Sn {R+ R- 4th Series.5th Series. 6th Series. The second and fourth of these series have not yet been produced by the method we are now considering. * Cahours Ann. Ch. Phgs. [3] lviii 22. 4-In these formula?R + represents a poaitive organic radical and R-a negative radical no negative organic radical as such has yet been introduced into these compounds. fa FRANKLAND ON ORGANO-METALLIC BODIES. FIRSTSERIES. Stannous ethide ( Sn2 {$;:) is produced in small quantities by the action of heat upon a mixture of iodide of ethyl and tin Iodide of ethyl. Stannous ethide Stannous methide is daub tless formed under similar conditions Iodide of methyl. Stannous methide. The TmRD SERIES of stann-organic compounds~ are formed by the following reactions + SnI Iodide of methyl.Dimethiodide of tin + SnI Iodide of ethyl. Diethiodide of tin. FIFTHSERIES. The following chemical changes express the mode of formation of compounds belonging to this series Iodide of methyl Stannic Iodotrirnethide. Lodide of ethyl. Stannic Iodotriethide. SIXTHSEnms.-The most abundant products of the action of tin upon the iodides of the alcohol-radicals belong to this series; indeed if the action be produced by light instead of heat this series of bodies is formed almost to the complete exclusion of the FRANHLAND ON ORGANO-METALLIC BODlEh $83 others. It is necessary however to remark that the materials exposed to light should be completely excluded from atmospheric oxygen otherwise the liquid assumes an orange colour and the action is so effectually arrested that an exposure for several months to sunlight concexltrated by a parabolic mirror will scarcely pro- duce any appreciable change.The following reactions explain the formation of bodies belonging to this series Iodide of methyl. Stannic dimethiodide. Iodide of ethyl Stannic diethiodide. Iodide of amyl. Stannic diamyliodide. It is evident that three series of tin-compounds are still wanting to complete the category viz. It is somewhat remarkable that no organo-tin compounds con-taining only one equivalent of positive radical have hitherto been produced. The inference to be drawn from this that such bodies do not exist must be checked by the fact that no special attempts have yet been made to form them.Organo.compounds of Mercury.-The reaction of mercury upon the iodides of the alcohol-radicals gives rise to two series of organic compounds the general formula of which may be thus written 184 'I;"RA.NHLAND ON ORGANO-METALLIC BODIES. 1st Series. 2nd Series. The first series only of these bodies can be produced by the general mode of formation now under consideration; but the members of the second series are readily obtained by the action of an organo-zinc compound upon those of the first. For the production of the first series of these bodies the action of light is essential except in the case of mercuric iodo-allide no elevation of temperature being capable of producing the chemical change.The following equations sufficiently exhibit the nature of the reaction Iodide of methyl. Mercuric iodomethide. Iodide of allyl. Mercuric iodo-allide For the production of the methyl-compound bright sunlight may be employed; but the reaction for the ethyl-body must be conducted in diffused daylight only otherwise no organo-metallic compound will be produced the ethyl being eliminated chiefly as such but partly also as hydride of ethyl and ethylene Iodide of ethyl. Ethyl. ~.~ Iodide of ethyl. Hydride of ethyl. Ethylene. In addition to these bodies compounds containing arsenic and antimony can also be produced by this general mode of formation; but they are obtained with greater facilitj by the second method which will now be described.FRANKLAND ON ORGANO-METALLIC BODIES. 185 2. Formation of organo-metallic bodies by the action of the respec-tive metals alloyed with potassium or sodium upon the iodides of the alcohol-radicals. The principles involved in this second general mode of produc-tion are essentially similar to those in the first but there is here less tendency to form compounds containing negative as well as positive radicals. This method although not capable of such general application is more especially adapted to the formation of the organic compounds of the polyatomic metals. The simulta- neous production of an organo-potassium or sodium compound need not be feared since such compounds cannot exist in the presence of the iodides of the alcohol-radicals.This mode of formation mill be sufficiently illustrated by the following reactions Jodide of methyI. Cscodyl. Iodide of ethyl. Ethxl-cacodyl. Iodide of methyl. Trimethylarsine. Iodide of ethyl. Trieth ylarsine. As Na {: = 3NaI Iodide of methyl Iodide of tetra-methylarsonium 4'4:5! ia 6 FRAISKLAND ON ORGAXO-METALLIC BODIES. + As{: Na + 3NaI Iodide of methyl Iodide of tetra-eth ylarsonium. Antimony-compounds. Iodide of methyl. Trimethylstibine. Iodide of ethyl. Triethylstibine. 3'10:11[ + Sb Iodide of amyl. Triamylstibine. Jodide of methyl. Iodide of tetra-methylstibonium. Iodide of ethyl. Iodide of tetre-thylstibonium. Iodide of amyl. Iodide of tetra-mylstibonium. FRAQNHLAND ON ORGANO-METALLTC BODIES.187 Tin-compounds. Iodide of methyl. Stannous-methide. Iodide of methyl. Stann-sesquimethide. Iodide of methyl. Stsnnic methide. Analogous reactions also represent the formation of the corre- sponding compouncis containing ethyl and amyl. Lead-compound. C,H5 3'4;5) + Pb Na = Pb C,H5 + 3NaT {:I {C,H5 Iodide of ethyl Plumb-sesquiethide Bismuth-compound. 3c4p) + Bi Iodide of ethyl Bis-triethide Tellurium-com~ounds. Organo-tellurium compounds are formed by a modification of this method which consists in distilling telluride of potassium with sulphovinate of potash and its homologues. 2(C,H30.S0 + KO.SO,) + 2KTe = Te {C2H3 + 4(KO.SO3) C,H Sulphomethylate sf potash. Tellurium-methyl. The ethyl and amyl compounds are prepared by homologous reactions.3. Formation of organo-metallic bodies 6y the action of the zinc- compounds of the organic radicals upon the haloid compounds either of the metals themselves or of their organo-derivatives. For the production of organo-metallic bodies containing less positive metals than zinc this method is perhaps not only the most 188 FKANKLAND ON ORGANO-METALLIC BODIES. convenient but also capable of the most general application. Com- pounds containing mercury tin lead antimony and arsenic have been thus produced but it has failed when applied to the haloid compounds of copper silver and platinum for although these bodies are violently acted upon the organic group does not unite with the metals.The following reactions represent the present state of our lrnow-ledge with regard to this method of formation :-Mercury-corn,ounds. ____ -___ Zinc-methyl. i’vlercuric methide. Zinc-me thyl. Mercuric chloromethide. Zinc-ethyl. Mercuric chlorethide. Mercurous ethide and mercurous methide have not yet been obtained either by this or any other process. The instability of mercurous compounds as sem in the inorganic oxide and iodide is brought to a climax in organic mercurous compounds; the latter are instantly transformed into metallic mercury and the more stable organo-mercuric compounds. Thus when zinc-ethyl acts upon mercurous chloride the following change results :-+ Hg + 2ZnC1 Zinc-ethyl. Mercuric ethide. Tin-compounds. FRANKLAND ON ORGANO-METALLIC BODIES.189 Zinc-ethyl. Stannic diethiodide. Xtannic ethide. Zinc ethyL Chlorotriethicic of tin. Zn + Zinc-ethyl. Stannic dichlorethide. Zinc-ethyl. Ziucostsnnous ethide. Zinc-ethyl. Strtnnic di-iodoe thide. Stannic diethylomethide. ____-_I Zinc-ethyl. Stannic iodo-trimethide. Stannic ethylotrirnethide. Lead-compomd. The following is the only reaction mhich has hitherto been effected by the method mhich we are now considering :-Zinc-ethyl. PliimLic ethide. Antimony-compoulzds. Zinc-me thyl. Trimethylstibine. 190 FRANKLAND ON ORGA4N0-METALLIC BODIES = (C*E-I52Sb C,H5 + 6ZnC1 b4H5 Zinc-ethyl. Triethylstibine. Arsenic-compounds. + 2As{: C1 = 2As{C2H3C2H3 + 6ZnC1 C,H Zinc-methyl.Trimethylarsine. Zinc-ethyl. Triethylarsine. 4. Formation of organo-metallic bodies by the displacement of a metal in an organo-metallic compourcd 6y another and more positive metal. Wanklyn to whoin we are indebted for this mode of formation regards this displacement of one metal by another as 8 case of true electrolytic decomposition. He thinks that in zinc-ethyl for instance ethyl is the electro- negative arid zinc the electro-positive member sodium being more electro-positive than zinc replaces the latter metal and forms sodium-ethyl. But he supposes that where the original organo-metallic body contains a metal less electro-positive than the hydrocarbon radical then the latter and not the metal would be eliminated by contact with a more positive metal.Cacodyl for instance when treated with sodium should give methyl and arsenide of sodium AS {:& + ~a,= AS + E;;;') Cacodj1. Arsenide of sodium. Methyl. This view the correctness of which is more than probable is supported by the action of potassium and of zinc-ethyl upon ammonia Ammonia. Potsssamide. FRANKLAND ON ORGANO-METALLIC BODIES. 191 Ammonia. Zincethyl. Zincamide. Hydride of ethyl. In accordance with this hypothesis Wan klyn considers that the ethyl in sodium-ethyl would be displaced by copper mercury platinum &c. and that sodium-ethyl is only in equilibrium with bodies whose respective positions in the electrical scale are either both of them within or both of them without the space lying between the electro-positive sodium and the electro- negative ethyl This fourth mode of producing organo -metallic bodies has hitherto been applied only to the formation of sodium and potassium compounds or rather double compounds of these bodies with zincethyl according to the following reactions Zincethyl.Double compound of sodium-ethyl asd zinc-ethyl. Zincet hy I. Double compound of potassium-ethyl and zinc-ethyl. Sodium also displaces mercury from mercuric ethide sodium-ethyl seems to be formed but the exact nature of the reaction has not been ascertained PROPERTIESORGANO-METALLIC OF BODIES. The organo-metallic compounds as a class are distinguished for the extraordinary energy of their affinities. With certain excep- tions presently to be noticed their disposition to unite with negative elements increases with the positive character of the metal and with the smallness of the atomic weight of the alcohol- radical.Thus organo-potassium and sodium compounds possess more chemical energy than those of zinc whilst the latter are more active than the compounds of arsenic antimony tin or lead. Again in the series belonging to each metal the methylic com- pounds are more energetic than the ethylic ones whilst the last greatly surpass the amylic compounds in this respect. But whilst 192 PRANKLAND ON ORGANO-METALLIC BODIES. these general principles govern the chemical energy of organo-metallic bodies their effect appears to be modified by the degree of saturation in which the metal exists.Although this circum- stance has hitherto received only very partial elucidation yet we have evidence of its existence in the case of organo-tin compounds. Both stannous ethide and stannous methide com- bine directly with atmospheric oxygen and the union takes place with tolerable rapidity ; but neither stannic ethide nor stannic methide is in the least degree acted upon by free oxygen at ordinary temperatures; even iodine acts upon them with difficulty. This diminution of chemical energy in organo-stannic compounds cannot be ascribed to the mere influence of the additional weight of hydrocarbon which they contain since stannous aniylide readily unites with free oxygen at ordinary temperatures although the single molecule of amyl which it contains is considerably heavier than the double atom of either methyl or ethyl present in the organo-s tannic compounds just cited.Organo-metallic compounds in a state of partial saturation play the part of compound radicals. They are uniatomic biatomic teratomic or quadratomic according to the number of molecules requisite to complete their saturation. On the other hand organo-metallic bodies in a state of saturation never perform radical functions they never undergo cliemical change without decomposition. Thus zinc-ethyl stannic ethide mercuric ethide and plumbic ethib all give substitution-products when they are chemically acted upon. The description of the special properties of the organo-metallic bodies may be conveniently commenced with the most positive of the class viz.Potassium and sodium series.*-These bodies have not yet been isolated; they are known only in combination with the corre-sponding zinc-compounds. The double compound of sodium-e thy1 and zinc-ethyl is the only one which has hitherto been submitted to analysis. Its formula is This compound first separates from its solution in zinc-ethyl as a transparent fluid which after some time solidifies to :t mass of large tabular crystals fusing at 27" C. but when once fused * Wanklyn Proceedings of Poy. SOC.,iu 341. FRANKLAND ON OBGANO-Bf ETALLIC BODIES 193 remaining fluid at several degrees below that point. On the application of a moderate heat gases are evolved and a mixture of sodium and zinc without carbon is left behind.The double compound decomposes water with great violence forming hydride of ethyl and the hydrated oxides of zinc and sodium. The behaviorxr with negative elements has not yet been studied. Its most interesting reaction consists in the absorption of carbonic acid which it transforms into propiouic acid. The sodium-ethyl alone takes part in this reaction :* Sodium-ethyl. Propionate of soda. A similar double compound containing sodium-lmethy.8 as well as the potassium-compounds of ethyl and methyl have been formed. They have not yet been completely investigated but it is believed that their coniposition and properties are perfectly analogous to those of sodium-ethyl No compoiind of any of these bodies with a negative element has been obtained.Their action upon carbonic acid proves that they possess a still higher reducing power than the corresponding organo-ziric compounds and they will therefore doubtless prove valuable agents for the substitution of positive groups for negative elements in cases where organo-zinc cornpounds fail to produce the desired effect. Sodium-ethyl decomposes the iodides of the alcohol-radicals in the cold with formation of iodide of sodium.? _ _ -~ Sodium-ethyl. Iodide of ethyl. Hydride of Ethylene. ethyl. Owing to this behaviour potassium and sodium compounds can only be prepared by method No. 4 Mugnesium series. $-The compounds containing ethyl and methyl only have hitherto been examined and the former alone submitted to analysis.These bodies possess a close similarity to * Wanklyn Chem. Soc Qu. J xi 103. I-Frank 1and Proceedings of Boy. SOC.,ix 345. $ Cnhours Ann. Ch. Phys. Iviii 17. VOL. XLII. 0 1$& FRANKLAND ON ORGANO-METALLIC BODIES. organo-einc compounds. Tkey are very volatile colourless liquids possessing a powerful alliaceous odour ; are spontaneously inflam- mable and decompose water with violence. They do not readily decompose the iodides of the alcohol-radicals and can therefore be prepared by method No. I. No compound of these bodies with negative elements has yet been produced They are in the condition of chemical saturation. Further details of their proper- ties are wanting. Aluminium and Glucinum series.*-Like the organo-compounds of the alkaline metals the aluminirim and glucinum compounds have not yet been isolated with certainty; they are known only in combination with the iodides of the respective metals and the composition of the ethyl and aluminium body only has been fixed by analysis.Its formula is These double compounds possess great chemical energy ; they are spontaneously inflammable volatile liquids which decompose water with explosive violence. They are attacked by zinc-ethyl forming iodide of zinc and very inflammable liquids which latter are believed to be the pure organo-compounds. They appear to be chemically saturated bodies and therefore incapable of direct combination. Further details are wanting. Zinc series.t-Three bodies belonging to this series are knomn vis.Zinc-amgl They are colourless transparent mobile volatile and odorous liquids composed of four gaseous volumes .of the hydro-carbon * Cahours Ann. Ch.Phys,,Iviii,20. 1.Frankland Chem. SOC.Qu. J. ii 297 and iii 44; Phil. Trans. cxlii 431 and cxlv 259. Wanklyn Chem. SOC.Qu. J. xiii 124. FRANKLAND ON ORGANO-METALLIC BODIES. 195 radical and two volumes of zinc-vapour the six volumes condensed to four. The methyl and ethyl compounds are spontaneously inflammable burning with a greenish blue flame. All three are saturated compounds incapable of direct combination. In contact with water they are instantly decomposed with formation of oxide of zinc and hydride of the organic radical. Zinc-methyl. Hydride of methyl.-. Zinc-ethyl. Hydride of ethyl. Gradually treated with oxygen so as to avoid too violent action they form the respective zinc-alcohols. Zinc-methyl Nethylate of zinc. Zinc-ethyl. Ethylate of zinc. Zinc-amyl. Amylate of zinc. The action of iodine upon organo-zinc-compounds consists in the transformation of both their constituents into iodides. +-I = 2~n1 + 2'2Pl Zinc-methyl Iodide of methyl. 02 196 FRANKLAND ON ORGANO-METALLIC BODIES. Zinc-ethyl. Iodide of ethyl. I = 2ZnI +2 Zinc-amyI. Iodide of amyl. Organo-zinc compounds behave in a manner exactly analogous in contact with the other halogens. Reactions like the foregoing point to the applicability of these cornpounds for effecting the substitution of positive groups for negative elements in compound bodies an application which has not failed to attract the notice of chemists.In addition to the reactions of this class given above as esamplcs of the formation of organo-metallic bodies by the third method the following have been realized With Binoxide of Nitrogen.* CH =2 NCHO ~(N,o,) +Zn jCgHs 2 2 5,~)0 23 Binoxide of Zinc-methyl. Dinitro-methylate nitrogen of zinc. Zinc-ethyl. Dinitro-etbylate of zinc. It will be perceived that these reactions are the exact analogues of the one already mentioned in the sodium and potassium series where carbonic acid treated with sodiurnemethyl and sodium-ethyl forms acetic and propionic acids. fa fact dinitro-methylic and dinitro-ethylic acids may be regarded as the analogues of acetic and propionic acid respectively ;the nitrogen here sustain- ing a biatoxnic character and replacing an equivalent amount of carbon.With Sulphnrous Acid.? Sulphurous acid. Zinc-methyl. Ahthy1odithionate of zinc. *Frankland Phil. Trans. 1857 p. 59. I-Hobson Chem. SOC. Qu. J. x 55 and 243. FRANKLAND ON ORGANO-METALLIC BODIES. 197 3(S,04) 3-Zinc-e thyl. Ethylodithionate of Line. With Terchloride of Phosphorus.* CiZnCl Zinc-methyl. Trimethylphosphine 6ZnC1 Zinc-ethyl. Triethylphosphine. There is no apparent obstacle to this reaction being pushed to its extreme limit in the case of pentatomic bodies such as phos- phorus arsenic or antimony. Mi. Buckton has rgcently at- tempted this in the case of antimony; but although evidence of the existence of a pentethide of antimony was obtained the body could not be isolated and its composition satisfactorily fixed.The great stability of the triatomic compounds of these bodies will probably present considerable disculty in the way of obtaining pentatomic compounds of an exclusively positive character such bodies being doubtless easily resolved into the more stable group-ings represented in the following equation Antimonic ethide. Triethyls tib ine. Ethyl. Whilst on the one hand organo-zinc compounds are thus capable of effecting the substitution of their positive organic group for negative elements they can on the other hand in certain cases replace hydrogen by zinc forming for instance with ammonia and its homologues a series of zincamides In this direction the following reactions have been recorded.? *Hofmann and Cahours Phil.Trans. for 1857,p. 578 j-Frankland Proc. of Royal SOC. viii 502. 198 FRANKLAND ON ORGANO-METALLIC BODIES. Zinc-ethyl. Ammonia. Zincamide. Hydride of ethyl. Zinc ethyl. Aniline. Zincphenylimide. Hydride of ethyl. -Zinc-ethyl. Diethylamine. Diethyl-zincamide. Hydride of ethyl. Zinc-ethyl. Oxamide Zincosimide. Hydride of ethyl. Zinc-ethyl. Acetamide. Binc-acetimide. Hydride of ethyl. Of the same nature apparently is the reaction between zinc-ethyl and acetic anhydride.* The members of the zinc-series unite with neutral salts to form compounds which have been but little examined.The following however are known :t Dinitromethylate of zinc and 0 + Zn '2"3 zinc-methyl iC2H3 Dinitroethylate of zinc and zinc-ethyl * When zinc-ethyl is added to acetic anhydride torrents of pure hydride of et.hyl are evolved ; the other product of the reaction has not been examined. Frankland Phil. Trans. 1857 p. 59. FRANKLAND ON ORGAPTO-METALLIC BODIES. 199 Finally it has been observed that zinc-methyl when generated in contact with methylic or vinic ether combines with these bodies forming* Methylatc of zinc-methyl 2(Zn jc2H3) + 2Eti 0 tC2H3 Ethylate of zinc-methyl 2 Cadmium 8eries.t-Only one member of this series is know& and that very imperfectly. So far as its properties are made out they appear to be perfectly analogous to those of the zinc compounds.Tin 8eries.f-A large number of organo-metallic bodies con-taining tin have been described. The existence of the following may be considered as clearly established a. Stannous compounds. Stannous methide or stanmethyl Sn {Ezgz Stannous ethide or stanethyl b. Sesqui-compounds. Sesquinzethide of tin Sesquiethide of tin Dimethiodide of tin Sn {ggi I Diethiodide of tin * Frankland Phil. Trans. 1859 p. 412. I. Wanklyn Chem. Soc. Qu. J. ix 193. $ Frankland Phil. Trans. 1852 p. 417 and Phil. Trans. 1859,~.401. Cahoure et Riche Compt. rend. xxxv 91 and xxxvi 1001. Lowig Ann. Ch. Pham. lxxxiv 3C8. A. Orimm Ann. Ch. Pharm xcii 383 Buckton Phil. Trans. for 1859 p. 423. Cahours Ann.Ch. Phya. lviii 22. 200 FRANKLAND ON ORGANO-METALLIC BODIES. E. Stannic compounds. Stannic methide Stannic ethide Stannic ethy lome thid e Stannic-ethylo-trimethide Stannic iodo-trimethide Stannic iodo-triethide Stanniv iodo-dimethide atannic iodo-diethide It is scarcely necessary to Qbserve that the iodine in the above compounds admits of replacement by any salt-forming radical and also by oxygen or sulphur Stannous compou7?ds are oily liquids soluble in alcohol and ether but insoluble in water and possessing a pungent odour. They cannot be distilled without decomposition being resolved FRANKLAND ON ORGAN0 -METALLIC BODIES. 201 into stannic compounds and metallic tin. They are in a state of partial chemical saturation only and therefore perform the part of radicals combining directly with chlorine oxygen &c.and forming well-marked bodies of great stability. Stannouv compoimda are bistomic and unite directly with free oxygen chlorine &c. to produce bodies of the stannie form. Thus stannous ethide forms with oxygen stannic oxydiethide. Stannous ethide. Stannic oxydiethide. Stannous cornpounds have never yet been observed to play a uniatomic part. No sesqixi-compound has been directly formed from n stannous body; the latter under the influence of iodine oxygen &c. seems to pass at once into the starlnic form. It must be remarked however that no direct experiments have been made with a view of revealing any uniatomic attribute which may attach to stannous compounds.Sesqui-compoundsof the form Sn R + have hitherto been very iR+ little examined. They are oily liquids uniting directly with nega- tive radicals forming an extensive series of compounds belonging to the stannic class a considerable number. of which have been studied. The following examples will serve to show the mode in which sesqui-compounds of this form pass into bodies of the stannic class Sesquiethide of tin. Stannic iodotriethide. Staanic iodotriethide. Stannic iododiethide. Iodide of ethyl. 202 FBAX'KLAND ON ORGAKO-NJ3TALLIC BODIES. No reduction of a sesqui-compound to a stannous compound has yet been effected although it can scarcely be doubted that an aqueous solution of diethiodide of tin for instance if treated with zinc would yield stannous ethide.On the other hand stannic ethide or methide in contact with iodine is transformed into a sesqui-compound vie. diethiodide of tin C4H5 CP5 2:; I Sn -j-1 = sn21c,LIs + 2~2~31 C,H Stannic ethylo-dimethide. Diethiodide of tin Iodide of methyl. Sesqui-compounds of the form Sn fgI are very little known. -b-In fact the diethiodide of tin the production of which from stannic ethyiodimethide has just been mentioned is the only one known with certainty. It is a colourless mobile liquid boiling with partial decomposition at 208" C. and possessing a most insupportable odour resembling essential oil of mustard. Heated with excess of iodine it is transformed into stanuic iododiethide Diethiodide of tin.Stannic iododi ethide. Stannic compounds of the form. Sn (%i are colourless mobile liquids possessing a slight ethereal odour. They are volatile without decomposition and are very stable. Being in the con-dition of chemical saturation they are incapable of direct com-bination. No body can act upon them without expelling one or more equivalents of positive radical. Thus when heated with hydrochloric acid stannic ethide yields stannic chlorotriethide and hydride of ethyl Stmnic ethide. Strtnnic chlorotriethide. Hydride of ethyl. FRANKLAND ON ORGANO-METALLIC BODIES. 203 With two equivalents of iodine the reaction is C*HS @; + 1, Sa = sn2{c4~5 '4:s) C4H5 + I Stannic ethide. Stannic iodotriethide.Iodide of ethyl. ,4nd with four equivalents of iodine Stannic ethide. Stsnnic iododiethide. Iodide of ethyl. Stanuic compounds of the form Sn {iI commonly called R-compounds of sesquistanethyl have been comparatively well studied. The oxides are in the anhydrous condition volatile limpid oily liquids which readily unite with water forming crystalline hydrates which have a powerful alkaline reaction and neutralize the strongest acids forming an extensive series of salts. These salts are almost all soluble in water readily crystallizable and of a very pungent odour. The stannic iodotriethide and the stannic triethylosulphate may be adduced as examples of the halo'id and oxysalts respectively Stannic iodotriethide I Stannic triethylosulphate Stannic compounds of the form Sn G'have also been very R- completely investigated.The oxides are white amorphous powders insoluble in water alcohol and ether. They dissolve in hydro-chloric hydriodic and hydrobromic acids forming colourless and 204 FRANKLAND ON ORGANO-NETALLIC BODIES. inodorous salts which crystallize in fine prisms. Most of the oxysalts can also be obtained in the crystalline form either from aqueous or alcoholic solutions. The iodide and sulphate of stannic diethide which may be regarded as representatives of the haloid and oxysalts have the following formuke Stannic ethylodisulphate Sn Stannic iododiethide I Stannic compounds of this form are readilyreduced to stannous compxmds; thus when a piece of zinc is plunged into a solution of stannic chlorodiethide stannous ethide is produced Stannic chlorodiethide.Stannous ethide. BISMUTH SsR;rEs.*-The following bodies belonging to this series have been described 1. Bismuthous ethide Bi -fCg5 2 Bisrnu thous dichlor et hide c 3. Bismuthous di-iodoc thide Bi CI Bi -!'f4? 4.Bismuthons dioxyethide * Breed Ann. Ch. Pharm. lxxxii 106; Diinhaupt Ann. Ch. Pharm. xcii 371. FKANKLAND ON ORGAXO-RIETALLIC BODIES 205 5. Double compound of bis-muthous aulphide with bismut hic sulp hot rie th ide These bodies have as yet been but very imperfectly investigated. Bismuthous triethide is a colourless or slightly yellow mobile liquid having an unpleasaat odour like that of stibethine.Exposed to the air it gives off dense yellow fumes inflames spontaneously and finally explodes. It is very instable begins to decompose at 50' or 6Q0C. and explodes violently when heated to 150' C. a temperature still below its boiling point. No direct compound of this body has yet been obtained; it behaves like a chemically saturated substance and when slowly oxidized in contact with water yields alcohol and hydrated oxide of bismuth Bismuthous ethide. Alcohol. When an alcoholic solution of bichloride of mercury is added to an alcoholic solution of bismuthous ethide mercuric ethocliloride crystallizes out whilst biamuthous dichlorethide remains in solu-tion + 2HgC1 = BiiCg5 + 2HgfCg6 c1 Bismuthous Bismuthous 1cIercuric ethide.dichlorethide. chlorethide From the bismuthous dichlorethide the diiodide and dioxyethide are prepared by double decomposition whilst the simtltltaneous action of sulphuretted hydrogen water bismuthous ethide and atmospheric oxygen is said to produce the double compound of bisrnuthous sulphide and bismuthic sulphotriethide. LEADSERms.*--The follotving bodies only are known the ethyl group alone having been explored * Lowig Ann. Ch.Pharm. lxxxviii 3iS; Bucliton Phil. Trans. 1859 p. 417. 206 FRANHLAND ON ORGASO-METALLIC BODIES. Didurnbic triethide I Plumbic oxytriethide Plumbic chlorotriethide Plumbic triethylosulphate Plumbic ethide The existence of the first of these bodies cannot be said to be clearly established; but by the action of an alloy of sodium and lead upon iodide of ethyl a colourless mobile volatile liquid is obtained which when dissolved in alcohol or ether and exposed to the air forms plumbic oxytriethide a body which is however more readily obtained by the decomposition of the chloride wit1 oxide of silver Pltimbic chlorotriethide Plumbic oxytriethide.Plumbic ethide is a colourless limpid fluid soluble in ether but insoluble in water and possessing a faint odour. It is not acted upon by oxygen at ordinary temperatures but chlorine bromine and iodine act violently upon it. Plumbic ethide belongs to the class of saturated bodies and is consequently incapable of forming compounds. When it is treated with hydrochloric acid hydride of ethyl separates and plumbic chloro-triethide is formed FRANETAAND ON ORGANO-METALTJC BODIES.Plumbic Plumbic Hydride of ethide. chlorotriethide. ethyl. From plumbic chloro-triethide the sulphates and other salts can be prepared by double decomposition. These salts may also be obtained still more readily from the oxide which is a crystalline volatile pungent body possessing a powerful alkaline reaction and attracting carbonic acid from the air. MERCURIC SEftIEs.*-This series is confined to bodies of the mercuric type no organo-mercurous compound having been yet produced. It comprises the following members Mercuric methiodide Mercuric methhydrate Xercuric methonitrate Mercuric methide Mercuric ethiodide Mercuric ethohydrate Mercuric ethonitrate Mercuric ethide Mercuric ethylornethide Hereuric methide and mercuric ethide are colourless ethereal volatile liquids insoluble in water but insoluble in alcohol and * Frankland Phil.Trans. 1852 p. 436 and Phil. Trans. 1859 p. 409 ; Diin-haupt Ann. Ch. Pharm. xcii 3’71;Strecker Ann. Ch. Pharm. xcii 57; Buokton Phil. Trans. 1858 p. 163 and 1859 p. 41’7. 208 FRANKLAND OX ORGAiYO-METALLIC BODIES. ether and possessing great stability. They are in a state of maximum saturation and cannot therefore unite with any other body without the displacement of an equivalent of positive radical. Thus with bromine mercuric etliide gives bromide of ethyl and mercuric ethylobromide ~- Mercuric 1\1e rcuric Bromide of ethide.e thy lobromide. ethyl. With hydrated sulphuric acid the action is __________ -~ Mercuric Mercuric Hjdride of ethide. ethosulphate. ethyl. Mercuric methide possesses the highest specific gravity of any known non-metallic liquid (3*069) Glass consequently floats upon its surface. Brought in contact with mercuric iodide mercuric methide and mercuric ethide are converted respectively into rricrcuric methiodide and mercuric ethiodide -Mercuric methide. 3l ercuric methiodide. Nercuric ethide. Mercuric ethiodide. The reaction with mercuric chloride is exactly analogous. The hydrates of mercuric methoxide and mercuric ethoxide are caustic allialine bases capable of expelling ammonia from its salts and behaving in a manner similar to the corresponding uniatomic compounds of tin and lead.The remaining mercury-compounds which may be considered as derivatives of these two bodies are represented in the above list by the iodides and nitrates they generally crystallize very readily and with the exception of the haloid compounds are soluble in water. When their aqueous solutions are treated with zinc they are decomposed the zinc becomes amalgamated and gaseous hydrides of the positive radicals are evolved. It is highly probable that there are two FRANKLAND ON ORGANO-METALLIC BODIES. 209 stages in this reaction organo-zinc compounds being first formed and then decomposed by contact with water ;thus with mercuric methiodide-Mercuric methiodide. Zinc-methyl and then Zinc-methyl.Water. Hydride of methyl. This view of the reaction is confirmed by the fact that when zinc acts upon mercuric methiodide at 150' C. zinc-methyl is produced. When one of the above iodides or the corresponding chloride or bromide is treated with an organo-zinc compound the negative element becomes replaced by the alcohol-radical of the zinc-compound ; thus when mercuric methiodide is treated with zinc-methyl mercuric methide is produced. And it is believed that by acting upon mercuric ethochloride with zinc-methyl mercuric ethylornethide is produced Mercuric ethochloride. Zinc-methyl. Mercuric ethylornethide. but this body has not yet been obtained in a state of purity; distillation gradually resolves it into mercuric methide and mercuric ethide Mercuric ethylornethide.Nercuric methide. Mercuric ethide. ANT~MONY SERms.*-This important series of organo-metallic bodies contains a greater number and variety of compounds than any other with the exception of the arsenic series. The remark-able polyatomic character of antimony and arsenic not only renders the possible number of their orgauo-compounds very * LSwig Ann. Ch. Pharm. lxxv 315 327; Landolt Ann. Ch. Pharm, lxxviii 91 ; Buckton Chem. Soo. Qu. J. xiii 115; Hofmann ibid xi 316. VOL. XIII. P 210 FRANKLAND ON ORGANO-METALLIC BODIES. large but the variation in the proportions of the positive and negative molecules gives an extremely wide range to their chemical character extending as it does from highly caustic bases on the one hand to powerful bibasic acids on the other.The following are the principal compounds belonging to tbis series Trimethylstibine Antimonic trimethoxide Ant imonic trimethochloride Iodide of tetramethylstibonium or antirnonic tetramethiodide \ Hy&ate of tetramethylstibonium or antimonic tetramethylhydrate Antirnonic trimethosulphate Triethy lstibine Antjmonic triethoxide FRANKLAND ON ORGANO-METALLIC BODIES. 211 Antimonk triethochloride Iodide of tetrethylstibonium or antirnonic tetramet hiodide Iodide of methylo-triethylstiboaium Sb or ant im onic triet hornethi0dide Hydrate of te tr ethylstibonium or antimonic tetrethylbydrate C*% C4H5 Antimonk triethodpht e Sb C4H5 i Sulphnte of tetrethylstibonium Sb or antimonic tetrethylsulphate Antimonic triethoxiodide Sb C4H5 r: Triam ylstibine P2 212 FRAXKLAND ON ORGAXO-BIETALLTC BODIES.An timonic triam ylchloride Antimonic triamylnitrate It is remarkable that we have as yet no decisive evidence in this series of the existence of a compound corresponding to cacodyl. It is true that such a body has been described under the name of stibbiamyl but subsequent experiments have failed to confirm its existence. Amongst organo-antimony compounds therefore the most simple form is Sb R+ Bodies of this form -K are the analogues of ammonia and need not be here described (2 since their history and also that of bodies having the form Sb R+ 12 will be found in a discourse upon u Ammonia and its Derivatives," delivered to this Society June 17th 1858 by Dr.Hofmann." The only bodies therefore of this series requiring notice here are those of the form Sb R + and their derivatives. When the [:! R- two atoms of R-are oxygen these compounds constitute what may be termed biacid antimony bases. They are formed either by the direct union of the stibamines (Sb R+ with oxygen. {;I) B+ + 0 = Sb[tz 0 0 * See vol. xi p. 252 of this Journal. FRANKLAND ON ORG-4NO-METALLIC BODIES. 213 or by the decomposition of the corresponding haloid compounds by means of potash thus-Sb R + 2KO = Sb R+ + 2KCl [El [;: C1 The stibarnines although in other respects the perfect analogues of the nitramines here evidently exhibit a much more highly positive character uniting with oxygen so energetically as to be spontaneously inflammable in the lower portion of the series.The biacid antimony bases are colourless transparent amor-phous and tenacious bodies; the ethyl base is easily soluble in water and alcohol but somewhat less soluble in ether. They possess a bitter taste are non-volatile and do not suffer any change when exposed to the air. Treated with potassium. they are reduced to stibamines R+ + 2K = Sb(B+ + 2KO R+ Fuming nitric acid decomposes the biacid bases with ignition; but when they are treated with dilute nitric or other acid the respec- tive biacid salts are produced. The oxysalts are soluble in water or alcohol; most of them crystallise without much difficnlty as do also the antimonic biniodides ;but antimonic triethobromide and triethochloride are liquids not volatile without decomposition insoluble in water but soluble in alcohol and ether.The existence of antimonic triethoxiodide has been recently proved by Strecker. It had previously been regarded by Merck as a protoiodide of stibethiue (Sb (C4H,J31). ARSENICSERIEs.*-This series is perhaps the most important and interesting amongst organo-metallic bodies ; it contains the first discovered organo-metal caoodyl the classical investigation of * Cadet (1760) MBm. de Nath. et Phys. de Savants Btrang. iii 633; Thenard Ann. Ch. lii 54; Bunsen Ann. Ch. Pharm. xxiv 27; xxvii 1; xlii 14; xlvi 1 ; Frankland Ch.Soc Qu. J. ii 299 ; Cahours et niche Compt. rend. xxxvi 1001; Landolt Ann. Ch. Pharm. lxxxix 301; Hofmann Chem. SOC.Qu. J. xi 316. Baeyr Ann. Ch. Phann. cvii 257 j cv. 265. 214 FRANKLAND ON ORGANO-METALLIC BODIES. which by Bunsen not only imparts a completeness to our know-ledge of this series but has afforded the clue to the successful interpretation of many phenomena met with in other analogous families. It will be convenient to divide its very numerous members into three groups. A. Csrgano-arsenical compounds of the type As is B. Organo-arsenical compounds of the type As g C. Organo-arsenical compounds of the type As All arsenical compounds permit of being arranged under these three types. The following are the principal bodies already investigated A.Organo-arsenical Compounds of the Type As i Cacodyl Ethylic cacodyl As {ZE Propylic cacodyl As (2;;? Butylic cacodyl As {2::? B. Organo-arsenical Compounds of the Type As R r3.E Oxide of cacodyl As C,H Sulphide of cacodyl Chloride of camdyl \ FEANKLAND ON ORGANO-METALLIC BODIES. 215 Chloride of cacoplatyl As Arsenious dioxymethide As p?3 0 Arsenious disulphornethide As S -rr3 Arsenious dichloromethide As lc2Ef Trime thy larsine Arsenious diethiodide Triethylarsine C. Organo-arsenical Compounds of the Type As \E This group may be conveniently divided into four families or sub-types viz. a. Bodies of the form As 6' and their derivatives. R- 6.Bodies of the form As and their derivatives. R-c. Bodies of the form As and their derivatives. 216 F.GK"LAND ON ORGANO-METALLIC BODIES. d. Bodies of the form As R+ a. Sub-type R-As p R- C2H3 0 Monomethylarsenio acid 0 0 As 0 i Monomethylarseniates Arsenic diaxydichlormethide As Arsenic tetraohtormethide C1 CI 6. Sub-type Cacodylic Acid FRANKLAND ON OBGANO-METALLTC BODIES. Cacod ylates Sulphocacod ylic acid Sulphocacodylates Terchloride of cacodyl As Ethyl-cacodylic acid AS E:thy 1- cacodylates Arseiiic triethQxide 218 FRANKLAND ON ORGANO-METALLIC BODIES. Arsenic triethosulphate Arsenic triethosulphide As C,H, r: Arsenic triethochloride R+ R+ d.Bodies of the form As[ R, R- C2H3 VI3 Oxide of tetr ameth ylarsonium As {c2H3 or arsenic tetramethoxide C2H Iodide of tetramethylarsonium or arsenic tetramethiodide Oxide of dimethyl-diethylarsonium As or arsenic dimethyl-diethyloxide FRANKLAND ON ORGANO-NETALLIC BODIES. 219 Iodide of dimethyl-diethylarsonium or arsenic dimethyl-diethyliodide Nitrate of dime th yl-die thy1 arsonium or arsenic di met hy1 -diet h ylni trat e Oxide of tetrethylarsonium or arsenic tetrethoxide Sulphate of tetrethylarsoniurn or arsenic tetrethylsulphate Chloride of tetrethylarsonium or arsenic tetrethylchloride Iodide of dimethyl-diamylarsonium or arsenic diamyliodide The organo-arsenical compounds belonging to the type As contain only positive radicals.They are volatile poisonous liquids insoluble in water but very soluble in alcohol and ether and possessing an insupportable odour. The lower members of the family are spontaneously inflammable whilst the higher ones also rapidly oxidise in air. They unite with negative elements with great energy manifesting in their combinations either a uniatomic or a teratomic character and producing bodies either of the form As R+ or As R-. Thus cacodyl fonns with g' 2 [.,I chlorine chloride of cacodyl and terchloride of cacodyl. 220 FEANKLAND ON ORGANO-METSLLIC BODIES. Caeodyl. Chloride of eacodyl. {:;2 + i'4 AS ~1 = AS ci Cacodyl Terchloride of cacodyl. Nethylic cacodyl boils at 170"C. and ethylic cacodyl between 185" and 190" C.Heated to 400' C. cacodyl splits up into metallic arsenic hydride of methyl and olefiant gas Cacodyl. Hydride of methyl. Olefiant gas. Bodies of this type can be regenerated by reducing agents from many of their uniatomic compounds ; thus chloride of cacodyl and metallic zinc give cacodyl and chloride of zinc Chloride of cacodyl. Cacody1. Organo-arsenical compounds of the type As forms viz. (2) As {E: R-Those belonging to the first are termed arsines and are the analogues of ammonia ; but like the corresponding antimony compounds in addition to their alkaloid function they have the power of combining with two negative atoms forming bodies of 1: the sub-type As ( R + . Thus triethglarsine combines with oxygen R-R-to form arsenic dioxytriethide.The lower members of the type FRAINKLAXD ON OEGANO-METALLIC BODIES 221 possess this property to such an extent as to render them spon- taneously imflammable in air. Compounds belonging to the second of the above forms are produced by the direct combination of the cacodyls with negative elements the oxides are bases of comparatively feeble power slowly combining with two additional equivalents of oxygen to form acids. Thus oxide of cacodyl by exposure to air slowly passes into cacodylic acid As p2 0 02 Oxide af cacodyl. Cacodylic acid The chlorine bromine and iodine compounds of the form we are now considering are volatile neutral bodies which may be regarded as the haloid salts of cacodyl.Heated in contact with bichloride of platinum the chloride of cacodyl presents an inte- resting re-action; two equivalents of hydrogen in the cacodyl become replaced by a biatomic molecule of platinum producing chloride of cacoplatyl. -r2:AS C2H3 + PtCl = (C23%,AS C,Bt 131 c1 + 2HC1 Chloride of cacodyl. Chloride of cacoplatyl. Cacoplatyl forms a series of compounds analogous to those of cacodyl. The only compounds of the third form yet known belong to the methylic group. Arsenious dioxymethide is a crystalline body of a neutral character soluble in water alcohol and ether un- changed by exposure to air but transformed by distillation with hydrate of potash into arsenious acid and oxide of cacodyl 2 AS-0 = AsO + As C2H3 I:”” r3 Arsenious dioxymethide.Oxide of cacodyl. Hydrochloric acid coiiverts it into arsenious dichlormethide C2H3 c2H3 As{ 0 +2HCl = As{ C1 c1 + 0, 0 4 r,,,’ dioxymethide. Arsenioiis dichlormethide. -Q 222 FRAN KLAND ON ORGANO-METALLlC BODIES. Hydrobromic and hydriodic acids produce a perfectly analogous change whilst sulphuretted hydrogen tranforms it into arsenious disulphomethide. The chloric compound can also be formed by heating arsenic trichlormethide to 50’ 1::::: C. As + “.3> As Cl ( Cl Arsenic Arsenious Chloride of trichlormethide. dichlormethide. methyl. The chlorine bromine and iodine compounds are neutral bodies of considerable stability; the two former are liquid the latter solid and crystalline.By the action of chlorine or oxidising agents they R+ R-are transformed iuto bodies of the form As Organo-arsenical compounds have been more thoroughly investi- E gated in the direction of the type As kR than in any other; conse- quently me find therJe bodies rather numerously represented E 1 especially under the subtype As R +. As the latter bodies in + (R -however are the strict analogues of the compounds of ammonium their chemical relations will be found fully described in Dr. Hof-mann’s discourse before alluded to R+ R -has only yet been explored in the rnethylic Sub-type As {;1 -group. The oxygen-compound constitutes anhydrous monomethyl- arsenic acid a direct derivative from arsenious dioxymethide PRANKLAND ON ORGANO-METALLIC BODIES.223 + 2Ago = As 0 Arsenious dioxymethide. Monomethylarsenic acid. This acid is bibasic forming stable and well defined crystallisable salts the formulz of which are represented by the general ex- pression The chlorine compound is exceedingly unstable ;it may however be formed at -lO°C. but is transformed at OOC into arsenious chloride and chloride of methyl Arsenic te trachlormethide Chloride of methyl. Arsenic dioxydichlormethide is a somewhat more stable body formed by the direct union of chlorine with arsenious dioxymethide. + C1 = As 0 Cl ArEenious dioxyrnethide. Arsenic dioxydichlormethide. Nevertheless even this compound readily decomposes with evolution of chloride of methyl Sub-type As H -The oxygen-compounds are feeble mono-:E ! It- basic acids of which cacodylic acid may be regarded as the repre- IR + sentative They are derived from the bodies As R + by direct io 224 FRANKLAND ON ORGA?&-O-SIETALLICBObIES.oxidation as already described. Cacodylic acid IS remarkable for its stability ;neither firming nitric acid nor a mixture of sulphuric ; and chromic acids attack it even at the boiling point and it may be heated to 200" C. without alteration. Although it is soluble in water and contains upward of 54 per cent. of arsenic yet it is not in the least poisonous. Several agents reduce cacodylic acid to the arsenious or even to the diatomic form. Thus phosphorous acid transforms it into cacodyl C2H3P2Z3 +2Asi 0 3P-p 0 = 2 As (&3 c 14 23 4- 3P0 0 Cacodylic acid.Cacody1. Zinc also produces the same result. Hydriodic acid gas con- verts cacodylic acid into arsenious dimethiodide (3% CP3 0 + 3HI = As + I + 380 0 0 The acid character of this body is so slightly marked as to render it capable of forming compounds in which it appears to play the part of a base. Thus with hydrofluoric hydrochloric and hydrobromic acids it forms the following compounds Hydrobromate of cacodylic acid As H 0 The hydrohromate reacts perfectly neutral. The cacod ylates have the formula 0 Lo2 Sulphocacodylic acid has not yet been isolated but its salts pre-sent the same relations to those of cacodylic acid as salts of sulphur-acids generally bear to those of oxyacids.Their formula is Sub-type As R + has hitherto been very little explored so 111 -(R -far its it is known but its members bear so close a resemblance to their analogues in the aritimony-series as to reqaire no further notice. SERIES.* The close rclatiorrs of tellixrinni to sulphiir TELLTTRIUM and selenium place the bodies of this series in the same position with regard to the sulphides and selenides of the alcohol-radicals as the antimony aiid arsenic series stand in relation to the corre-sponding compounds of phosphorus and nitrogen. The following bodies belonging to this series are knoim Tellurium methyl Telluroiis clirnethoxirle Telluroiis methoxychloride Cl * Wdhler Ann. Ch. Pharm. xxxv 112 lxxxiv 69 Mallet Ann.Ch. Pharm. lxxix 223 ; Wdhl er and Dean Ann. Ch. Pharm. xciii 233. VOL. XJII 9. 226 B'RANKLAND ON ORGAKO-METALLIC I?OI)IEP. Tellurium-ethyl Tellurous diethoxide C4H* Tellurous diethosulphide Te p:5 S Acid tellurous diethosulphate C*% Te {%: so4 Tellurous diethochloriclc Tellurous diethoxychloride ,,.i"": Tellurous diethiodide I Tellurium-amyl The compounds of the alcohol-radicals with tellurium are vola- tile liquids of most unbearable odour. They orridise readily in contact with air forming tbe respective oxides. Tellurium-amyl has not yet been obtained in a state of purity. The oxides of these bodies are powerful bases expelling ammonia from its salts and attracting carbonic acid from the air.They form salts of considerable stability which as well as the oxides themselves yield the original organo-tellurium compounds when ,treated with sulphurous acid FRANKLAND ON ORGANO-METALLIC BODIES. 227 Tellurous diethoxide. Tellurium ethyl. Constitution and Theoretical Importanceof Organo-metallic Bodies. In the year 1852*,at a time when comparatively little progress had been made in the investigation of organo-metallic bodies I ventured to propose a view of their constitution which further research has cotnpletely confirmed. According to this view the organo-metallic bodies are constructed upon the types of the inorganic chlorides sulphides oxides &c. of the respective metals which they contain the chlorine oxygen stdphur &c.being replaced in equivalent proportion and step by step by the alcohol- radicals. A reference to the formuh of organo-potassium sodium magnesium zinc and cadmium compounds given above shows that they are all formed upon the models of the protochlorides of these metals ; the general type being {: 3% In like manner organo-aluminium compounds are formed upon the type of the sesquichloride of that metal Organo-tin compounds are represented by the three chlorides of tin The compounds of the bismuth-seyies me represented by the terchloride of bismuth and by bismuthic acid 1: 0 Bi * Phil. Trsna. for 1852 p. 438. Organo-lcad comporxnds :w :wrm(yd under the tppcs of sesqiiioxide and peroxide of lead 0 Pb {’:0 P+ 0 The mercury-series are all mouldcd upoii the type of the bichloride The arsenic and antimony swies have for their types the following inorganic compounds Sb fC1 , C1 ZCI The inorganic models for the tellurinm series are ctil&le of telliirium and telluroixs acid Occasionally an abnormal componnd has made its appear-ance such as ethostibilic acid (Sb (C El,) 0,) or iodide of triethylstibinc (Sb (C H5)3J); but farther research has invariably demonstrated the incorrectiiess of SUC~ forrnulze and the conformity of the bodies with the normal inorganic types.Indeed this law may now be regarded as sufficiently established to be applicable to the control of the formulce of new organo-metallic bodies. From the point of view thus afforded it is interesting to watch the effect of the substitution in metallic compounds of basjlous or positive for chlorous or negative radicals.Such a substitution affords striking evidence of the dependence of the chemical character of a colapound upon that of each individual constituent. The highly poly atomic metals such as arsenic and antimony exhibit this dependence in the most conclusive manner. Thus tribasic arsenic acid by the substitution of an equivalent of methyl for oxygen yields the bibasic monomethyl-arsenic acid a well defined acid of considerable energy though inferior in chlorous power to arsenic acid. The like substitution of a second equivalent of rnethyl for oxygen reduces the chlorous character of the body to the com-paratively feeble condition in which we find it in cacodylic acid which is incapable of forming an ammonia-salt.A similar substi- tution for the third time overpowers the acid attribute of the compound altogether and we now have a feeble biacid base the arsenic dioxymethide which again by the exchange of a fourth atom of oxygen for methyl is transformed into the oxide of tetra-methylwsonium a base of such energy as to be comparable with the caustic alkalies themselves. The behaviour of the organo-metallic bodies teaches a doctrine which affects chemical conipounds in general and which may be called the doctrine of atomic saturation ;each element is capable of combining with a certain limited number of atoms ;and this number can never be exceeded although the energy of its affinities may have been increased by combination up to this point.Thus zinc appears to attain its atomic sattzratioa by uniting with only one atom of another body; in other words it is uniatomic consequently the zinc compounds of’the alcohol- radicals not wit tist anding their intense affinities are incapable of direct union with other bodies. The action of chlorous elements upon them is apparently one of substi-tution not of combination. Polyatornic metals exhibit the same phenomenon. A Gouble atom of tin cannot combine with more than four atoms ; a siiigle atom of arsenic or antimony with more than five atoms of other bodies ; but in the combinations of poly- atomic metals me frequently notice from the lowest to the liiglirst coinpound one or more intermediate points of exalted stability ; thus antimony has a teratomic stage of comparative stability ; nitrogen *phosphorus aiid arsenic whilst exhibiting a similar ter- atomic stage have also a biatomic one tliough of greatly inferior stability ; whilst the existence of protoxide of nitrogen renders it more than probable that nitrogen has a third and uniatomic stage.Inbodies possessing at least one stage of stability below saturation and in which all the atoms united with the yolyatomic element are of the same kind the stage of maximum stability is very rarely that of saturation. Tlms in niirogen arsenic and bismuth com-pounds of the kind just Ynentioncd the stage of maximum stability is decidedly the teratomic one; in antimonial cornpounds of a similar nature the teratomic is also though less decidedly the stage of maximum stability whilst in pliosphorous compounds the 230 FRANKLAND ON 0RGANO-R.lETALLIC BODIES points of maximum stability and of saturation generally coincide 'When however the atoms united with the polyatomic element are not of the same kind then the stage of maximum stability usually coincides with that of saturation.Thus the binoxide or bichloride of triethylarsine or triethylstibine are more stable than triethylarsine or triethylstibine themselves ;hut this pentatomic stability reaches its climax in arsonium stibonium and phos-phonium compounds as it does also in the corresponding com-pounds of nitrogen although the latter element exhibits a much stronger tendency towards universal teratomic stability than its chemical associates.In polyatomic organo-metallic bodies it is remarkable that with few exceptious the positive hydrocarbons hold their position much mctre tenaciously than the associated negative constituents ; ar?d we thus frequently find the former accompanying the metal through a vast number of compounds. Hence the group formed by the metal and positive hydrocarbons has come to be regarded as a compound radical. Thus cacodyl is conceived to be the radical of the whole series of cacodyl compounds. Rut however great may be the convenience of this mode of viewing organo-metallic corn- pounds and the same mode has notoriously been extended to nearly all organic bodies it must not be forgotten that it is a purely artificial distinction which has no real existence either in the case of organo-metallic bodies or as 1 shall endeavour to show in that of organic bodies in general.A close examination of the habits of the so-called organo-metallic radicals shows clearly that their atomic power depends upon their position with regard to the stages of stability and maximum satixration ;thus they are uniatomic when the number of positive groups is one less than that required to reach either the maximum saturation of the metal or a lower stage of stability. Cacodgl and tetramethyl-arsonium for instance are uniatomic radicals because they are respectively one atom short of the stage of stability and of maximtim saturation Uniatomic stage.Stage of stability. As C,H, -r Cacodyl. Chloride of cacodyl. FRANKLAND ON ORGANO-NETALLIC BODIES. 231 Uniatomic stage. 8f?gcof maviniuln saturation. - ____.-_ Tetramethylarsonium. Chloride of tetramethylarsonium. It is obvious that a compound radical the number of whose positive atoms is below that of a stage of stability can have a double atomic character. Thixs cacodyl is sometimes uniatomic as in oxide of cacodyl ;and sometimes teratomic as in cacodylie acid. Again arsenio-monomethyl (AsC,H,) is biatornic in arsenious dioxymethide and quadratomic in monomrthylarsenic acid If these views of the constitution and character of organo-metallic bodies and their compounds be correct their application to the organic compourids of carbon becomes inevitable.Regarded from this point of view the double atom of carbon like that of tiu is quadratomic in perchloride of carbon and carbonic acid ~ C~i~ G{S0 Yerchloride of carbon. Carbonic acid. and biatomic ip protochloride of carbon and carbonic oxide (Q {E c2 c2 (0 Protochloride of carbon. Carbonic oxide. In other words the quadratomic stage in carbon-compounds is the stage of maximum saturation whilst the biatomic stage is one of exalted stability. If we substitute an atom of chlorine in per- chloride of carbon by one of ethyl we produce a body having the formula of trichlorhvdrin If now a second atom of chlorine be substituted by one of hydrogen we have a body exhibiting the composition of bichloride of propylene This view of the constitution of bichloride of propylene renders its relations to ally1 and glycerin compounds at once simple and intelligible.The substitution of a third atom of hydrogen gives the forinula whilst the substitution of tlic last atom of' chlorine by hydrogen yields hydride of propyl and its replacement by ethyl yields the so-called double radical ethylpropyl. It still remains for experiment to produce these bodies from perchloride of carbon and to show that they are identical with the known compounds possessing the same percentage composition.* If however 117e turn to the oxygen-compounds of carbon we are not entirely without experi- mental evidence of the correctness of this view ; since one atom of oxygen in carbonic acid has been replaced by ethyl with pro-duction of the body theoretically indicated namely propionic acid Could a second atom of oxygen be substituted by hydrogen we ought to produce propionic aldehyde * Such experiments are in progress but are not sofficiently advanced to be here quoted FRANKLAND ON OKGAKO-ME KALLIC BODIES.233 The replacement of a third &tornof oxygen by hydrogen would then yield propylic ether whilst the replacement of the last atom of oxygen by hydrogen should give rise to hydride of propyl and by uniatomic peroxide of hydrogen to propylic alcohol Hydride of propyl. Propylie alcohol. The glycols are also constructed upm the carbonic acid type Glycol.arid to the same type belongs also the teracid alcohol glycerin. Under the influence of iodide of phosphorus glycerin yields iodide of allyl -Glycerin. Iodide of allyl. Phosphoric acid Here we have a reduction from the carbonic acid to the car- bonic oxide type of precisely the same nature as that which occurs when cacodylic acid is reduced to oxide of cacodyl. Allylic compounds are therefare constructed upon the carbonic oxide type* 234 FRANKLAND ON 0RGANO-21 ETALLIC I%OI)IE3. Carbonic oxide. Iodide of allyl. Allylie alcohol. It would be easy greatly to extend this view of the constitution of organic carbon compounds; but the above examples are sufficient to indicate its geueral application somewhat more fully than 1 have previously done,* and more than this is not desirable until the hypothesis has been further supported by experimental results.In conclusion it is evident that this is only one mode of applying to organic compounds the law of chemical eornbination which I have endeavoured to deduce from the constitution and behaviour of organo-metallic bodies. Its application ought to be and will be found to be equally truthful in referring organic compounds containing hydrogen oxygen or nitrogen to the inorganic typical compounds of each of these elements. Thus for example we can represent alcohol lst as derived from carbonic acid Znd as derived from teroxide of hydrogen 3rd as derived from water In like manner nitrogen compounds and their analogues whilst derived from typical inorganic compounds of nitrogen are also * Ann.Oh. Pharm. ci 260; Proc. of Royal Inst. of Great Britain for 1858. It is highly remarkable that more than thirteen years ago when such analogies were of the most obscure kind the quick perception of Liebig led him to point out analogous relations between carbonic acid alcohol formic acid and marsh gas. See Ann. Ch. Pharm. Iviii 335.) FOSTEIt ON ACETOXYBENZAMIC ACID. true derivatives from the carbon types. Thus trimethylamine is correctly written as a derivative from carbonic acid Each of these modes of notation is equally correct; bat I conceive that a large number of those organic bodies which are usually formulated in accordance with the hydrogen water and hydrochloric acid models mould be much more usefully expressed upon the carbonic acid aud carbonic oxide types.The formulation of organic compounds is not a matter of indifference even to the chemical investigator; and hence every mode of expression founded upon broad chemical relations ought to have the preference over more purely artificial methods.

ISSN:1743-6893    

DOI:10.1039/QJ8611300177

出版商:RSC    

年代:1861

数据来源: RSC

摘要:

235 FOSTEB ON ACETOXYBENZAMIC ACID. XX.-On Acetoxybenzarnic Acid an Isomer of Wippuric Acid. BY G. C. FOSTER. IF we regard hippuric acid as benzoyl-glycocol or glycocol in which an atom of hydrogen is replaced by benzoyl it seems natural to expect that an acid isomeric with and analogous to hiypuric acid might be obtained by replacing an atom of hydrogen in oxgbenzamic acid (syn. benzamic acid amidobeneoic acid) by ncetyl. From the results recorded in this paper it appears that such is the case. When oxybenzamic acid is heated in a sealed tube with about half its weight (rather more than one equivalent) of monohydrated acetic acid the whole mass becomes quite fluid at about 130' or 140°C. but solidifies almost entirely at about 160° all that remailis liquid king the portion of acetic acid used in excess.The reac-tion which takes place is the following :-C7H7N0 + C2H,02 = C,N,NO +-H20.* Oxybenzamic Acetic Acetoxybenzamic acid acid. acid. Using at a tirm from 15 to 20 granimes of oxybenzamic acid T found that thc reaction 'CI tij quitc complete after an hour's heating to 160° especially if advautage had been taken of the period of complete liquefaction to mix thc materials thoroughly. The same product is also formed by tile reactioii of chloride of acetyl on ovybenzamate of zinc-f at 100" C7€I,%nN02 + C2H,0Cl = C,H,NO + ZnCl. Oxybenzamate of Chloride of Acetoxybenzamic zinc. acetyl. acid. On mixing chloride of acetyl with oxybenzamate of zinc sufficient heat is given off to volatilize a considerable part of the chloride of acetyl if care be not tziken to condense it and tlie whole quickly soliclifies to a hard mass (probably a combination of the two sub-stances analogous to the combination of hydrochloric acid with oxybenzamic acid) which in a sealed tube at looo melts arid then again gradually solidifies ; complete solidification iiidicates the end of the reaction.Oxybenzamate of zinc heated with two equivalents of acetic acid or a mixture of equivalent quantities of hydrochlorate of oxybenzamic acid and acetate of calcium with a little acetic acid yields the same product ; but neither of these processes is advanta- geous on account of the high temperature required and the difficulty of thoroughly mixing the materials.* C = 12 0= 16 + Oxybenzamate of zinc is easily obtained by mixing solutions of chloride of zinc and oxybenzamate of calcium. It separates as a granular precipitate which is very easily washed on a filter. It is nearly insoluble in water but soluble in acetic acid. *3624 grm. dried at loo" was boiled with carbonate of sodium till completely decomposed the resulting carbonate of zinc yielded on ignition .0921 grm. oxide of zinc. Calculated. Found. Zinc percent. . . . . 21.16 20.42 I have found the formation of this salt to be a convenient method of separating oxybenzarnic acid from impure solutions. The substance yielded by these reactions is easily purified. It is sufficient to dissolve it in an alkali to precipitate the solution by hydrochloric acid and to crystallize the precipitate two or three times from boiling water or alcohol.Any colouring matter which still adheres to the product thus obtained may be completely removed by animal charcoal. I have named the new substance ace~oxybenxamicacid. Dried over snlphuric acid it does not lose weight at 100". -3788 grm. prepared fcom acetic and oxybcnzamic acids gave ,8382grm. carbonic acid and -1'766grm. water. -2913 grm. prepred ffom chloride of acetyl and osybenzamate of zinc gaw -6396 grm. carbonic acid and *139 grm. water. *4363grm. of another similar preparation gave 9677 grm. car- bonic acid and ,1987' grm. water. *3302grm. of the same product heated with soda-lime gave a platinum-salt containing 02375grm.platinum.* .4-1.42 grm. of the same product gave 29.2 ec. nitrogen at 0" and '760 mm. pressure. Calculated. Found. f 1.. L4. Mean. C 108 6033 60.36 59.88 60.49 - - 60.24 H 9 5.03 5.18 5.23 5-06 - - 5-16 N 14 7.82 - - - 7.50 8.25 8.02 0 48 26.82 - - - .- .__ 26.64 __I_ C,H,NO 179 100*00 100*00 Acetoxybenzamic acid is obtained as a white powder which under the microscope is seen to be formed of needle-shaped crystals. It is almost insoluble iu cold water and in ether and is onlyrnoderately soluble in boiling water or in cold alcohol j in boiling alcohol it dissolves easily. It has a slightly bitter taste a good deal resembling that of nitre. Like its isomer liippuric acid it dissolves readily in a solution of common phosphate of sodium giving an acid reaction to the liquid but is reprecipitated by acetic or a mineral acid.It is soluble in strong sulphuric acid without colouration in the cold and also in glacial acetic acid ; these solutions are precipitated by dilrrtion with water. A mixture of * In the decomposition of acetoxybenzamic acid by soda-lime very little ammonia is formed ; nearly the whole of the nitrogen is given off as aniline. FOSTER ON ACETOSYBENZAMIC ACID. acetoxybenzamic acid with sufficient strong hydrochloric or nitric acid to make it flow eqsily becomes nearly solid on standing for a few minutes but it was found that a mixture of hydrochloric acid and acetoxybenzamic acid loses all its hydrochloric acid when dried under a bell-jar over lime and snlphuric acid.At about 200"acetoxybenzamic acid sublimes somewhat rapidly ; it melts between 220" and230" and enters into ebullition at about 260" apparentiy undergoing decomposition at the same time. It may be boiled for a long time with water and even with dilute acids without undergoing perceptible change ; but when heated in a sealed tube with hydrochloric or dilute sulphuric acid to about 140"it is decomposed into oxybenzamic and acetic acids just as hippuric acid is decomposed under similar circumstances into glycocol and benzoic acid. A quantity of hydrochlorate of oxy- benzamic acid thus obtained gave the following results on analysis : r- ~3767grm. burned with chromate of lead gave -677 grm. car- bonic acid and ,1719 grm.water. *4399em. gave *3624grm. chloride of silver. Calculated. Found. Carbon . * . . 48.42 49.01 Hydrogen . . . 461 5.07 Chlorine . . . . 20.46 20.39 Another quantity of acetoxybenzamic acid was deromposed by dilute sulphuric acid of 10 per cent. When the decomposition was complete the contents of the tube were transferred to a retort and distilled. The distillate was saturated with carbonate of barium filtered and evaporated. The barium-salt so obtained proved to be acetate of barium. $8039grm. dried at 120° gave -7365 grm. sulphate of barium. Calculated. Found. C2W,Ba0 Barium per cent. . . . 53.73 53.72 The residue iu the retort deposited on cooling crystals of sulphate of oxybenzamic acid. Acetoxybenzamic acid is similarly decomposed by a.n alcoholic solution of hydrochloric acid but oxybenzamate and acetate of ethyl are formed at the same time as the corresponding acids.The FOSTER 03 ACETOXYBENZAMIC ACID. 239 decomposition takes place slowly in the cold but quickly at 100". On distilling the product of the reaction in a water-bath a light ethereal liquid possessing the smell and general properties of acetate of ethj-1 passed over with the excess of alcohol and was separated from it by the addition of water. The residue in the retort crystallized on cooling in radiating needles. The crystals which mere very soluble in water and alcohol but slightly soluble in ether were recrystallized from water washed with ether and dried over sulphuric acid. *4748grm.gave -3501 grm. chloride of silver. -392 grm. gave -2924grm. chloride of silver. -5091 grm. burned with chromate of lead gave 09642grm carbonic acid and -2638grm. water. These results correspond to a mixture of the hydrochlorates of sxybenzamic acid and oxybenzamate of ethyl. Hydroehlorate of Found. Hydrochlorate of oxybenzamic acid. oxybenzamate of ethyl. Carbon . . . 48.42 5 1-65 53.60 Hydrogen . . 4.61 5.76 5.96 -Chlorine . . . 20.64 18.24 18.45 17.62 What was left of the crystals after making the above analyses was dissolved in water a slight excess of milk of lime added and the whole shaken up with ether. The ether left on evaporation an oily liquid apparently oxybenznmate of ethyl which was nearly insoluble iu water but soluble in hydrochloric acid giving a chloride insoluble in ether and combining readily with bichloride of platinum.The quantity of the platinum salt obtained was not sufficient for a determination of the percentage of platinum. The aqueous liquid from which the ether had been poured off was filtered and the excess of lime separated by carbonic acid. After being somewhat concentrated by evaporation it gave with chloride of zinc a precipitate resembling oxybenzamate of zinc. Attempts were made to obtain acetoxybenzoic acid C9H8OQ isomeric with benzoglycollic acid by the action of nitric oxide on a mixture of nitric acid and acetoxybenzamic acid and also by the action of nitrous acid on a briiling aqueous solution of acetoxyben-zamic acid but in both cases the only product was a nitro-substi- tution compound.Acetoqbewamate of pntassium was prepared by digesting a solution of tlie acid in strong alcohol with dry carbonate of potas- sium. It is exceedingly soluble in water and dissolves easily in alcohol but is precipitated from this solution by ether. From a solution in alcohol containing more tliaii about 10 per cent. of water,it is precipitated by ether in the form of a strong aqueous solution which solidifies only after standing for a considerable time. Acetoxybenzamate of sodium CgH8NaN0 + xH,O. -This salt was prepared in the same way as tlie potassium salt. It is very soluble in water and easily soluble in alcohol but can be obtained crystallized soinewhat inore easily than the potassium salt.It is insoluble in ether and is not deliquescent. -468 grm. dried between 120' and 1304 gave 01636 grm. sulphate of sodium. Calculated. Found. (:91-l,Eax0, ~ Sodium per cent. . . 11.44 11 -32 Acetoxybenzamate of barium C,H,BaKO + 1 $€I,O. -0btaiiied by saturating a hot aqueous solution of the acid with carbonate of barium. It is very soluble in water and crystallizes by the spontaneous evqoration of its solution in minute radiating needles grouped together in tufts. It dissolves readily iii spirit of wine but is precipitated from a strong aqueous solution by absolute alcohol. It loses only a part of its matcr of crystallization at 100"; for analysis it was dried between 138' and 145'. 1.8858 grm. dried over sulphuric acid lost -1812 grm.water between 130"and 14So. *8776grm. lost *Of387grm. water at the same temperature. ~6464grin. of the dry salt gave *3027grm. sulphate of barium. -3783 grrn. gave -1774 gri. sulphate of barium. 03918 grm. gave .1824 grrn. sulphate of bariuln. a9185 grm. burned with chromate of lead gave 1.4625 grm. carbonic acid and ,288 grin. watcr. Calculated. Found. 108 43.81 /--43.43\ c9 HE3 8 3-25 --3.48 Ba 68.5 27.79 27.54 27.32 27.42 --.__ N 14 5.68 -48 19.47 --03 -__. _I__-C9H,BaN0 246.5 100 00 FOSTER ON ACETOXYBENZAMIC ACID. 241 Calculated. Foyd. CSH,BaWO + 1iH,O -7 Water of crystallization . . 9.87 9.61 10.11 Acetoxybenznmate of calcium C9R8CaN0 + l+H,O.-This salt was prepared by saturating the acid with milk of lime and removing the excess of lime by carbonic acid.It is only moderately soluble in cold water and can be easily obtained in well-defined crystals consisting of very thin rhombic plates by cooling its hot aqueous solution. ,6428grm. air-dry lost *081grm water at 130". -63 grm. lost *0781grm. water at 130". -2978grm. dried at 130° gave -1039 grm. sulphate of calcium. -2087grm. gave -0722grm. sulphate of calcium. ,342grrn. burned with chromate of lead gave *6786grm. car-bonic acid and *1337grm. water. Calculated. Found. -. h 108 54.55 /--54.12 C9 H* 8 4-04 -4.34 Ca 20 10*10 10.26 10.17 -N 14 7.07 --03 48 24.24 ---"-C9HsCaN0 + l+H,O Water of crystallization . . . 12.0 12.6 12.4 Acetate of lead gives with a solution of ail acetoxybenzamate a sticky precipitate which melts in boiling water and gradually dissolves; it is also soluble in alcohol.Nitrate of .doer and chloride of zinc give no precipitate with a nioderately strong solution of an acetoxybenzamate. With a con-centrzted solution nitrate of silver gives ft. prscipitste which blackens on boiling. Acetoxybenzamate of ethyZ.-This substance cannot be obtained by the process indicated by Stenhouse for the preparation of fiippurate of ethyl namely by heating the acid with alcohol saturated with hydrochloric acid. The manner in which acetoxy- benzamic acid is decomposed under these circumstances has already been described. When acetoxybenzamic acid and absolute VOL. XITI. R 242 FOSTER ON ACETOXYBENZAMIC ACID alcohol are heated together no apparent action takes place at looo; but at about 150" a compound is formed ahich is soluble in ether and can thus be separated from the acid which remains in excess.This body which is probably acetoxybenzamate of ethyl is very slightly soluble in cold water but tolerably soluble in hot water; from this solution it sometimes separates by cooling in the form of an oil which solidifies gradually on standing. If long boiled with water it regenerates acetoxybenzamic acid. It is very soluble in alcohol. On heating this substance to 100" in a Liebig's drying-tube in order to dry it for analysis a few drops of a colourless liquid which was scarcely soluble in water but miscible with alcohol and which greatly resembled carbolic acid in taste and smell condensed in the tube leading to the aspirator.As this liquid continued slowly to distil after the substance had been heated for many hours to looo the temperature was raised to between 130"and 135'. At this temperature the liquid distilled more rapidly and mas accompanied by a crystalline sublimate; at the same time the supposed acetoxybenzamate of ethyl rapidly became of a dark brown colour. Neither the liquid nor the sub- limate was obtained in sufficient quantity for further examination. Cahours* mentions a substance which he obtained by the action of chloride of benzoyl on oxybenzamate of silver but of which he neither gives the formula nor describes the properties. Hoping to obtain benzoyl-oxybenzamic acid I reacted on oxybenzamate of zinc with chloride of benzoyl.The product was an acid insoluble in cold water and in ether slightly soluble in boiling water in alcohol and in chloroform and resembling acetoxybenzamic acid in taste and in its appearance under the microscope. A determination of nitrogen by D u m as's process and the mean of two concordant combustions gave the following results :- Carbon . . 68.03 Hydrogen . . 5-12 Nitrogen . . 6.27 Oxygen . . 20.58 1oo*oo which differ too much from the calculated composition of benzoyl- oxphenzarnic acid ; nnmely-* Ann. Ch. Pharm ciii 90. This product is spoken of as glycobeiizamic acid in the Handw6rterbnch FOSTER ON ACETOXY BENZAMIC ACID. 24!3 Carbon .. 69.71 Hydrogen . . 4.56 Xitrogen . . 5.81 Oxygen . . 19.92 100*00 It is a matter of some interest to consider the relation in which acetoxybenzamic acid stands to hippuric acid and the nature of the isomerism of these two bodies. If we bear in mind the close analogy which exists between glycocol and oxybenzamic acid the formation of acetoxybenzsmic acid from chloride of acetyl and oxybenzamate of zinc is strictly comparable to the formation of hippuric acid from chloride of benzoyl and zinc-glycocol ; and its decomposition wheri heated with water in presence of a strong acid into acetic and osyben- zamic acids is analogous to the decomposition of hippuric acid into benzoic acid and glpcocol. C,H,OCl + C,N6ZnN0 = CgHgN30 + ZnCl Chloride of acetyl.Oxybenzamate of zinc. Acetoxybenzamic acid. C,H,OCl + C,H,ZnNO = CgHgNO + ZnC1 Chloride of benzoyl. Zinc-glycocol. Hippuric acid. CgKgNO3 + H,O = C,H,O + C,H,NO Acetoxybenzamic acid. Acetic acid. Oxybenzamic acid CgHgNO + H,O = C,H602 + C,H,NO Hippuric acid. Benzoic acid. Glycocol. Allowing for the difference between acetyl and benzoyl acetoxy- benzamic acid is to oxybenzamic acid what hippuric acid is to glycocol. The simplest way of expressing these relations in the formula? of the two substances is to write acetoxybenzamic acid as an acetyl-derivative of oxybenzamic acid (or as oxybenzamic acid in which an atom of hydrogen is replaced by acetyl) and ‘hippuric acid as a benzoyl-derivative of glycocol (or as glycocol in which an atom of hydrogen is replaced by benzoyl).Before we can give formulz which will indicate the further relations of these acids it is therefore necessary to consider the formulae of glycocol amid oxybenzamic acid. These two bodies occupy corresponding positions in two analogous series of compounds. R2 FOSTER ON ACETOXTBENZAMIC ACID. Acetic acid . C2H4O2 Benzoic acid C7H602 Chloracetic aci .d C2H,C102 Nitrobenzoic acid C,H (NOJO Glycocol . . C2H5N02 Oxybenzamic acid C7H7N02 Glycollic acid C2H*O3 Oxybenzoic acid C,H60 There are two principal points of view from which the members of the two series may be regarded and accordingly two principal. systems of rational formula by which they may be represented. We may on the one hand adopt formuh expressing only the genetic relations of the two sets of compounds to acetic and benzoic acids respectively; or on the other hand formula which express in addition the general nature of the differences which the various terms of each series exhibit in their relation to other substances.In the first case if we write acetic and benzoic acids as deriving from the type H20 we get- Acetic Series. Chloracetic acid . * C2H,,O) 0 Glycollic acid . C2R,(HHO)) 0 Benzoic Series. Berizoic acid Nitrobenzoic acid . Oxybenzamic acid . C7H4(H2N)0] 0 H L Oxybenzoic. acid In the second case we get the following or equivalent forrntih :- FOSTER ON ACETOXYBENZAMIC ACID. Acetic Series. Type.Acetic acid . . CHOJ .. 22Hio Elo Chloracetic acid Qlycocol * Glycollic acid . Benxoic Series. Benzoic acid . . CHO '*HI0 .. :lo Nitrobenxoic acid Oxybenzamic acid . Oxyhenzoic acid It will be seen that these two systems of formula3 differ in this that in the first set the type remains unchanged throughout but that the radicle is different in each compound; while in the FOSTEIl ON ACETOXYBENZAJIIC ACII). second set the type is variable but the radicle constant. It may perhaps be said that this difference is not essential but merely a difference of form the elements which in the one case are represented as replacing hydrogen in the radicles acetyl and beiizoyl and are written in the same line with the remaining elements of these radicles being in the other case separated and written above the other elements.Admitting this to he the case and supposing the two sets of formu18 to be used in the same sense the question arises whether or no one set of forrnuh is preferable to the other as a matter of form. On this point it may be observed first that the only consistent definition of a compound radicle is a group of elements contained in a greater or less number of substances and not altered by the reactions by which these substances are tramJ-bmed one iizto anof her and that it is therefore inconsistent to represent closely allied and mutually convertible substances as containing different radicles ; secondly that the only consistent iise of typical formuh is to express the nature of the tra?~~or~ut~ons which the bodies repre- sented by them are capable of undergoing and therefore that it is inconsistent to refer to the same type bodies of which the trans-formations are very different.For example the forniula+- Benzoic acid Nitrobenzamic acid Oxybenzarnic acid ought to imply that the salts of these three acids give similar products when acted upon by acid chlorides such as chloride of acetyl or chloride of benzoyl experiment however proves that the first two give anhydrides when so acted upon while the third gives a well characterized acid. The same difference .also exists between the salts of acetic acid and the salts of glycocol in respect to their behaviour with similar reagents. For these reasons the relations of glycocol and oxybenzamic acid to their congeners are most correctly expressed by the €armula3-and CHO 'H4 >' ol~cocol.Oxybenzamic acid. which represent them as amidic acids corresponding respectively to FOSTER ON ACETOXYBENZAMIC ACID. 247 giycollic (oxyacetic) acid and oxrbenzoic acid. Hence for hippuric and acetoxybenzamic acids we get the formule-Hippuric acid. Acetyl-oxybenzamic acid. (Benzoyl-oxyacetamic acid.) By way of justification of this discussion of what may seem very obvious formul~e I may perhaps be allowed to give a collection {probably far from complete) of formullx which have recently been proposed for glycocol hippuric acid and oxybeiizarnic acid. GI;LYCOCOL. HIPPURIC ACID.OXYBENZAMIC ACID. CLH302 N N{ : { q3 Gerhardt Trait6 iv 767 (1856). C14H5(H2x>04 Cahours Ann Ch. Phys. [3] liii (1858). Wislicen us Zeitschr. f. d. gesammt. Nsturwissenschaften xiv (1859) * W eltzien Zusnmmenstell. d. organ. Verbind. (1860)% * / * 4 I 4k /? C~H~HZ)O~ C,,FNHZP H }02 H ‘}O2 Borup-Besanez Lehrb. d. organ. Chemie ii (1860) * (‘2 { 2N) [c2’21’0 Ho’C&2 ;:{ { 2N) c202}Ec2’21,0 Ho*(‘12 { 2N) [c&021J0 Kolbe Ann. Ch. Pharm. csiii (1860). co Limpricht Lehrb. d. organ. Chemie (1860). * In the forrnnls marked with an asterisk 33:= 1 C 6 0= 8. 1= FOSTER ON ACETOXYBENZBMIC ACID. It is hardly necessary to add in conclusion that I make no claim to originality in reference to the formuh proposed in this paper.Gerhardt in the formula quoted above represented lrippiiric acid as benzoyl-glycocol and the formulz which I have adopted for oxybenzamic acid and glycocol were first proposed by Keliule' (Ann. Ch. Pharm. civ. 148; cvi. 150). Moreover the formulze for glycocol arid hippuric acid which are quoted from Limpricht are very nearly identical with those proposed in this paper The only difference is that in order to represent other reactions than those which are here taken into account he has divided the radicle C2H20 into CO and CW, and has consequently derived giycocol and hippuric acid from the type H5N1 ,which might perhaps be more correctly 890I ;for though in some compounds nitrogen is com-bined with the equivalent of five atoms of hydrogen these substances are always easily broken up into a group equivalent to H and a group equivalent to H,N Through the kindness of Professor ICekul6 of the University of Ghent I have been able to perform the experiments described in this paper in his laboratory.Ghent 19th Jzcne 18GO.

ISSN:1743-6893    

DOI:10.1039/QJ8611300235

出版商:RSC    

年代:1861

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FOSTER ON ACETOXYBENZAMIC ACID. XX7;.--On Baudrirnont’s Protosulphide of Carbon. BY LYONPLAYPAIR, C.B. F.R.S. PROFESSOB OF CHEMISTRY IN THE UNIVERSITY OF EDINBURGH. Baudrim ont has given various processes for the preparation of protosulphide of carbon a body long expected by chemists aBd necessary to complete the analogy between sulphur and oxygen. Protosulphide of carbon bears the same analogy to carbonic oxide that bisulphide of carbon does to carbonic acid. The discovery of the body surprised no one but it was a matter of astonishment that the numerous and simple processes for its preparation had rcrxiairied so long unknown to chemists. BAUDRIMONT’S PROTOSULPHIDE OF CARBON. 249 The description given by Baudrimont * for the preparation and properties of this interesting body is short further details being promised in a future paper.Meanwhile the new compound has received admission into systematic works on Chemistry. Being desirous of making some experiments with protosulphide ofcarbon I have repeated without success the processes described by Baudrimont ; I have been equally unsuccessful with others which appeared equally promising. It is therefore desirable to obtain further evidence of this existence of the compound; for the products of the processes described are in most cases only carbonic oxide with the vapours of bisulphide of carbon and in other cases mixtures of carbonic oxide hydrogen carbaretted hydrogen and the vapours of bisulphide of carbon. Baudrirnont in the memoir above referred to gives nine processes for the preparation of protosulphide of carbon but admits that only the first process yielded it in a state of tolerable purity.To this process it will therefore be sufficient to direct special attention. The vapours of bisulphide of carbon are to be passed over red hot pumice-stone or spongy platinum which have the effect according to Baudrimont of doubling the compound (so much sulphur being at the same time deposited as to choke the exit tubes) while tlie gaseous protosulphide of carbon passes on and may be collected after transmission through solutions of acetate of lead and dichloride of copper. In repeating this and subsequent experiments it became obvious that the presence of organic matter and moisture was a frequent source of error and it was necessary to operate so as to exclude these ;accordingly the following arrangement was adopted :-A long tube of difficultly fusible glass was filled with fragments of pumice-stone to the extent of three feet in length and then the posterior end was drawn out into a U shape and the anterior end into a delivery tube for gaseous products The capacity of the whole tribe was about 95 cubic centimeters.The body of the tube containing the pumice stone was placed in Hofmann’s gas furnace and heated ti stream of carbonic acid dried by sulphuric acid being passed over it until all moisture was expelled. When the desiccation of the tube and pumice-stone had been effected 8 grammes of dry bisulphide of carbon were sucked into thc TJ portion of the tube which was then sealed by a lamp and placed in a water-bath.* Comptes rendus xliv 1000. 250 YLAYPAIR ON The whole of the bisulphide of carbon was now slowly passed over the red hot pumice and the products were collected over mercury by the delivery portion of the tube. The heat employed was sufficient to alter the shape of the tube although it was protected as is usual in combustion by metallic gauze. During the experiment gas came over and with it liquid bisul- phide which condensed in the eudiometer. After the 8 gramrnes of bisulphide had been slowly passed over the red hot pumice- stone the products were as follows :-Gas at 730mm. press. 12°C. temp. . . 155 cub cent. Liquid bisulphide of carbon .. . . 5 cub. cent The gas corrected for temp. and pressure and for the tension of CS with which it was saturated (200mm. at 12°C.Brezelius) gave Corrected vol. of gas and 0°C. and 760mm. press. 103.5 cub. cent. Caustic potash was now passed up to absorb carbonic acid and sulphuretted hydrogen and the gas now measured 59 cub. cent. at 12°C. and 610mlu. pressure still saturated with bisulphide of carbon. Corrected for this and brought to the normal temperature and pressure there was only 30.49 cub. cent. of gas left. Hence of the 8 grammes of bisulphide at least 6.4 grammes were found condensed in the eudiometer ; the remaining 1.6 gramme was chiefly in the long delivery tube which had a column of Condensed bisulphide in it but this was not measured.If we neglect this and assume that 1.3 gramme was decomposed into pro-tosulphide of carbon (0.3gramme in vaponr being allowed for the capacity of the tube) 383 cub. cent. of this gas should have been produced. But after correcting for the pressure temperature and for the tension of CS, only 30.49 cub. cent. mere obtained. This small quantity of residual gas consisted of carbonic oxide and nitrogen resulting from the traces of air and moisture still left in the pumice-stone or introduced when the bisulphide of carbon was drawn into the apparatus. But if we assumed the whole residual gas to be protosulphide of carbon it would have BAUDBIMONT’S PROTOSULPHIDE OF CARBON. 25 1 weighed only 0.060 gramme and would have been produced from 0.09 gramme of the bisulphide.Hence in any case not more than 1%per cent. of the bisulphide employed could have been decom- posed in its passage through the red-hot pumice. Rut this gas was chiefly carbonic oxide produced by the action of moisture- (CS +HO =CO +S +HS,) and required only 0.027 €30to produce it a quantity which can easily have escaped the drying process. A careful examination of the tube and pumice-stone showed that no sulphur whatever was deposited except one or two specks which could not have been weighed the whole operation having been one of simple distillation without decomposition. When the pumice-stone is not completcly dry then sulphuretted hydrogen and carbonic oxide appear while sulphur is deposited. Having failed in obtaining protosulphide of carbon by th2 only process which Baudrimont describes as giving it pure it was scarcely necessary to repeat t6e other methods; but those described as yielding the best results were examined The chief of these is to pass the vapours of bisulphide of carbon over red-hot charcoal animal charcoal being recommended.On repeating khese experiments large quantities of gas were obtained at first; but the gas ceased abruptly although the tube still contained abundance of animal charcoal and now bisulphide of carbon distilled over unchanged. The gas collected in the first part of the experiment was washed with solution of acetate of lead and dichloride of copper but continually decreased in bulk until only a small quantity remained.This was analysed with the following resdts :-20*295cub. cent. gave Carbonic oxide . . 11-79 Bisulphide of carbon . 4.66 Nitrogen . 3.83 20.28 The analysis was however only approximate as some sdphuric acid was formed in the combustion of the gas. A like experiment made with wood-charcoal gave precisely similar results. Both these experiments proved that the gas at first obtained was due to the organic matter and moisture acting on the bisulphide of carbon and that the latter distilled_over unchanged as soon as the former were removed. 252 NEW AMMONIO-CHROME COMPOUND. It is unnecessary to describe the other experiments made in the hope of procuring protosulphide of carbon as they all gave negative results.Baudrimont gives as evidence of the compositon of the gas obtained by him (1)that lime-water decomposed it into sulphide of calcium and its own volume of carbonic oxide. It is clear that this experiment was not a quantitative one as no allowance is made for the solubility of the protosulphide of carbon which is stated to dissolve in its own bulk of water. Hence the result may have been due to a mere mixture of carbonic oxide containing the vapour of bisulphide of carbon and a little sulphuretted hydrogen. (2) B audrimont states that eudiometric analysis gave equal volumes of CO and SO,; but this result would be equally attained by the combustion of a gas containing equal volumes of CS and CO ;and at the ordinary temperature with the diminished pressure in the eudiorneter the tension of CS is more than suffi-cient to double the volume of gas in the tube.It may further be remarked that Baudrimont does not give any process for removing bisulphide of carbon from the gases obtained by him. In conclusion it must be admitted that there is no sufficient evidence of the existence of protosulphide of carbon all the processes described for its preparation having failed to yield it. Buff and Hofmann* seem to have been equally unsuccessful in their endeavours to obtain it from bisulphide of carbon by electric incandescence.

ISSN:1743-6893    

DOI:10.1039/QJ8611300248

出版商:RSC    

年代:1861

数据来源: RSC

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NEW AMMONIO-CHROME COMPOUND. XXII.-Notice of a New Ammonio-Chrome Compound. BY3. MORLAND, F.C.S. WHENsulphocyanide of ammonium is fused and powdered bichrornate of potash added to it this salt dissolves quietly at first giving a purple coloration. After a short time however it very brisk reaction ensues ammonia and aqueous vapour are given off abundantly and %heresidue is of a beautiful crimson colour. This residue consists of sulphocy anide of ammonium sulphocyanide of potassium bichromate of potash sulphate of potash and the sulphocyanide of a new ammonio-chrome com- * Journal of Chemical Society xii 283. MORLAND ON AN AMMONIO-CHROME COMPOUND. 253 pound; this last salt is easily purified from the others by washing with cold water in which it is but sparingly soluble and after- wards by crystallization from alcohol which dissolves it freely or from ether in which it is moderately soluble.This new salt has the composition Cr Csy 2?JH,O. Analysis gave the fol- lowing figures :-Theory. Fomd. Cr 18.71 18-71 when the salt was dried at 120"C s 34.53 34.37 N 25.18 24.96 C 12.95 13.27 H 2-88 3-39 0 5*76 This is a perfectly neutral salt crystallizing in the cubical system. I obtained crystals by the spontaneous evaporation of an ethereal solution the form of which was the rhombic dodecahe- dron modified by the planes of the octahedron it has a strongly bitter taste especially at the back of the mouth. Heated in a closed tube it gives off ammoniacal vapours sulphuretted hydrogen and some compound of cyanogen with a garlicky odour ; the residue is sulphide of chromium which when heated in the air ignites gives off sulphurous acid and leaves sesquioxide of chromium.Neither acids nor alkalies decompose this salt in the cold but alkalies on boiling throw down oxide of chrome; and acids when concentrated decompose it by uniting with the ammonia. Heated on the water-bath with sulphuric acid it yields sulphate of ammonia and blue sulphate of chrome; oxalic acid gave violet oxalate of chrome and oxalate of ammonia Persalts of iron are not coloured by this salt but nitrate of silver immediately gives a precipitate of uncertain composition as much of this chrome salt is carried down. Other chromates as well as bichromate of potash also form this same salt with fused sulphocyanide of ammonium; chromate of potash and chromate of lead succeed pretty well but there are also other substances formed.I found the best proportion to be 5 of sulphocyanide to 2 of bichromate corresponding to 1 eq. bichromate to 5 of sulptrocyanide. FrB my's roseo-chrome salts have the composition (Cr,03.4NH3).3A GLADSTONE ON CIRCULAK POLARIZATION. which differs chiefly in the double quantity of ammonia. The cobalt-bases have according to FrBmy the following compo-sitions :-PO,~ 4 xrs3 5> Y.l 5 5J 6 fJ I have attempted to form other compounds by the reduction of chromates in the presence of ammonia-salts but at present without success.

ISSN:1743-6893    

DOI:10.1039/QJ8611300252

出版商:RSC    

年代:1861

数据来源: RSC

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GLADSTONE ON CIRCULAR POLARIZATION. XXII1.-On Circular Polarization. A Discourse delivered to the Members of the Chemical Society of London. BY DR. J. H. GLADSTONE, F.R.S. WHEN,at the request of the Council I undertook to bring the subject of circular polarization before the Chemical Society I did not realize the quantity of the observations which have been recently accumulated by the industry of foreign savans. In preparing this discourse I have been well-nigh overwhelmed with materials and I have therefore considered it best to omit all description of the more purely physical questions and to confine myself as closely as possible to those branches of the subject which have R direct hearing on chemical science. Circular polarization was first observed in quartz by Arag o in 1811; it was investigated by B iot,* and the subject speedily attracted the attention of some of the leading physicists of this country.Brewster Herschel and Airy made important discoveries in respect to it; but since that early period very little has been done by the scientific men of Great Britain while in France and other parts of the continent investigations have rapidly extended and circular polarization has been taken advantage of for the solution of many chemical problems. It is true that won after the formation of our Society Leeson read an elaborate * Mem. Inst. 1812 and subsequently. GLADSTONE ON CIRCULAR POLARIZATION communication on the subject;* some of Pasteur’s papers have been translated in our Quarterly Journal,? and the matter has of course been referred to in lectures and treaties on Nattiral Philo- sophy;$ yet there can be no doubt that British Chemists have generally made themselves but little acquainted with the sub- ject.The leading phenomena of circular polarization are simply these. If a slice be cut from a crystal endowed with this property in a direction perpendicular to its axis and it be examined by polarized light it does not exhibit the coloured rings and black cross; and if the emergent polarized ray be analysed by a doubly-refracting prism the two images have complementary colours which change as the prism is made to revolve. If such a slice of crystal or a liquid possessing the same power be placed between the polarizer and analyser of a polariscope the maximum and minimum of light are in fact not attained when the plane of reflection is inclined to that of polarization at 0’ and YO’ but at some other angles 90’ apart.The amount of this deflection will differ with the colour-that is with the refrangibility of the ray ;thus a violet ray will be deflected to perhaps twice the distance of a red ray; and hence when white light is employed a series of coloiirs are ob-served following one another in regular succession as the analyser is made t.ii revolve. If in order to make these follow in their natural order-red orange yellow green blue violet-it is necessary to turn the arialyser to the right-that is to say in the direction of the hands of a watch-the substance is said to exhibit right-handed or positive circular polarization which is usually indicated by the sign A~’or + if on the coutrary the analyser must be turned to the‘”1eft to produce the same result the polarization is left- handed or negative and the sign <I or -is employed.On revolving the analyser beyond the violet rays the same order of colours beginning with red reappears and there is a transition tint called by the French teint de passage or teint sensible which from its sensitiveness is very valuable for obser- vations. * Mem arid Proc. Chem. Soc. ii 26. t Chem. SOC.Qu. J. iii 79; v 62; vi 273 277. $ For instance in Golding Bird’s Elements of Natural Philosophy; in Pereira’s Lectures Pharm. J. ii and iii; in Graham’s Elements of Chemistry 2nd Edit.Vol. ii p. 464;and in a lecture by Maskelyne Phil. Mag. (4) i 428. GLADSTONE ON CIRCULAIL. POLABIZATJOR. For the explanation of these phenomena on the undulating theory I can only refer to Fresnel's Memoirs.* Substances which exhibit Circular Polarization.-T f ie following table contains a list of the substances in which the phenomena of circular polarization have been observed. It is doubtless incom- plete; and it must be borne in mind also that the effects are produced by very many compounds of some of these bodies which are not included in the table. Against the name of the substance is placed the sign -f-or - to indicate the direction of the rotation and in another column the name of the observer who first remarked the property in the substance in question or who has worked upon it to the greatest effect.Where a second observer has discovered the existence of a power of rotation in a direction opposite to that first discovered which is by no means an UZL-common circumstance or has otherwise largely extended our knowledge of the subject his name has generally been added. The last column indicates whether the substance has been ob-served to form hemihedral crystals either itself or in its com- pounds. -Hemi-Substance. Direction. Authority. hedral? --.__I_-Quartz crystal . . .. + or -Arago Biot Brewster Herschel Hem. Chlorate of soda (solid). . + or -Marbach Hem. Bromate of soda (solid). . + or -Acetate of uranium and + or ->J soda (solid) .. 1 Cinnabar.. .. . . + or -Descloizeaux Oil of turpentine .. + or -Biot Seebeck Leeson Oil oflemon .. .. + >2 Oil of hergarnotte .. -+ >> Oil of anise .. .. Oil of carraway ,. . . + >7 Oil of spearmint . . -J? Oil of rue ,. .. -1) ?9 Oil of nutmeg .. .. + Leeson Oil of lavender .. .. -Oil of cubebs .. .. _. W iyh e 1my Oil ofvalerian .. .. -J> Oil ofamber .. .. -CaBtor oil .. .. + Yf Croton oil .. .. -+ )I 1, Balsam of copaiba .. Camphor.. .. .. + or -Biot "C h an tard * Ann. Ch. Phys. (2) xxviii 147. This is abstracted in Daguin's Trait6 El&-mentnire de Physique which contains many of the most recent observations on the subject. GLADSTONE ON CI RCU Lhlt POLARTZATTON. Substances.Direction Authority. Hemi-tedral? -______I_-_-Camphoric acid .. Camphoethylic acid Camphomethylic acid Naphtha .... ..j Cane-sugar . . Milk-sugar .. Grape-sugar . Starch-sugar .. Diabetes-sugar ,. Clucosate of sea-salt Tartaric acid . . Malic acid .. Tartramide .. Asparagine .. Tartramic acid .. Aspartic acid .. Sulphamylic acid Amylic alcohol .. Formobenzoie acid Quinicacid .. Quinine .... Quinjdjne .. Quinrcine .. Cinchonine . . Cinchonidine .. Cinchonicine . . Quinoidine . . Ivforphine .. Brucine .... Strychnine .. Narcotine .. Nicotine .... Santonine .. Hcematoxylin .. Jalapin .... Phloridzin . . Salicin .... Populin .... Codeine .... Narceiue ....Picrotoxinc .. Albumin .. -..; + .. 4-..I -..j t -.I ..I 4-../ +or-../ f I. I. .. .. .. .. .. .. ,I .. .. .. .. .. .. I. .. .. .. .I .. .. .. *. *. .. .. I__ Boucharda t Chant ard Hem. Ma 1 ag 11t i Hem. Loir Hem. Biot , Clerget Hem. , Poggiale Hem. , BQchamp , Clerget Listing Pasteur Hem. Biot Pasteur Arndtxen Hem. P aste 11r Hem. Hem. 7 Hem. 17 Hem. )I 9 Not >f 79 Hem. Bou c h ar d a t Paste 11r 1 ?3 Pasteur Bot~c hard at Pasteur Bou c h ar ds t Paste 11 r Hem. Y , Descloizcsux Wit.h eifmy 99 ?I J. Bou&ardat Biot and Paeteur Biot and Pasteur Bouchardat and Boudet 9) ,1 9 7 A.Becqnerel I have not attempted to express in this table the amount of rotatory force possessed by the different substances not from any lack of numerical data but for the following reasons :-1st. It has been frequently determined differently by different observers. This arises to some extent from actual optical dif- ferences in the samples employed :thus oil of turpentine is known to possess different powers of rotation even when the direction remains the same according to the kind of pine from which it T’OL. XTII. 3 GLADSTONE ON CIRCULAR POLARIZATION. came and the processes adopted in preparing and purifying it. Again the amount of solvent employed is a fruitful cause of diversity. 2nd. Unfortunately in determining the rotatory force no uni-form standard has been adopted.Thus Biot reduces his observa- tions ta a unit of thickness-namely one millimeter and he calculates from the arc of rotation of the rays that have passed througli red glass. He employs the following fiirrnula for deter- mining the specific rotatory power (p) in vhich a stands for the arc of rotation d the density and I the thickness or length in millimeters. a p=-dl And if the substance be dissolved in some optically neutral solvent the proportion of the said substance in one part of the solution (p) has to be taken into account and the formula stands- a P = --d Ip Wilhelmy,* on the contrary laying stress on the molecular nature of the force considers it preferable to take the different substances in quantities proportional to their atomic weights in equal weights of the solvent; and vhere he cannot do this he makes a reduction on the hypothesis that the relative quantity of the solvent has no influence.He makes his calculations also for white light and assumes the molecular rotating power of cane sugar as 100. A table given in one of Wilhelmy's paperst is so good an illustration of the elaborate investigations that have been made into this subject that I have reproduced it here I I Molecular Quantity Atomic rotating Snlxhnce. Solrent. White Red weight. power. dissolved Light. Light. 0 =100. (White -___I -----I1ght.) ni illipr . Cane-sugar ...... 4309 Water +3$5 +250 2154.5 f100 Nicotine ......1301 Alcohol -16 -with hydrochloric acid , >> 4-I(?) Santonin ...... 500 -9 +6'7 3005 -332.3 YJ Hematoxylin .... 1849 ,I .. +13-5 Jalapin ...... 2000 *. -7 7t I I *Pogg. Ann. lxxxi 413 499. $ Ibid Ixxxi 52'7 GLADSTONE ON CIRCULAR POLARIZATION. -MoIecular Degree of rotation. Atomic rotating luaittit Solvent. Wiiite Red weight. power. issolve Light. Light. 0 =100. (White ---llgllt.) milligr Camphor .. .. . 6000 Alcohol + 310 t-22O 963.8 + 30.7 .I Phloridzin .. .. 2377 3) -11 -8.7 2082.5 -59.2 Quinine .. .. . 1782 > -24 -20 }2055.5 -174 .I -.. .. 891 I -12'5 -9.65 -with nitric acid 13 >> -17 .. -241.4 t. -with phosphoric acid . . >> -15 .. .. -213 WaGr & Sulphate of qainine .. 1000 sulp. acid -24.5 -16.7 Valerate of quinine . . Alcohol -16 -13 Hydrochlorate of quinine .. S'O'O -10 3J Cinchonine .. . . . . 454 ,> 4-12 .. 1942 +315.8 -with oxalic acid 494 + 12.5 .. .. + 302 9, -with phosphoric acid .. 952 + 23.5 .. .. + 295 ?> -with nitric acid .. 930 33 + 20 .. .. + 257 -.. 465 79 + 10 99 ?9 Quinoidine.. . . .. 374 1) 4-945 +8 -with nitric acid .. 99 + 9.75 -with phosphoric acid. . 19 + 10 -with hydrochloric acid 97 ?f + 10 1 9, -with sulphuric acid . + 11% I7 Brucine .. .. .. &4 71 -8 .. 3448 -172.5 -with phosphoric acid 0 >> Narcotine with sulphuric 936 Water + 5.5 *. 4684 + 169 acid .. .. 1 It Acetate of morphine .. 490 ,? -4 Hydrochlorate of codeine ..578 -5 Ethereal oil of cubebs . 7460 Al&hol -33.5 ___-, valerian . 7480 Ether -15.4 ' Balsam of copaiva .. .I 7560 Ether with alch. -11.5 Iqluence of state of Aggregation.--The only substance which has been examined in the three different states of aggregation-the solid liquid and gaseous is oil of turpentine and it has been found to exhibit the power in each of these states. It rotates the plane of polarization to the same extent when frozen as when in its ordinary liquid condition ;but Biot who made the experiment on the vapour of turpentine was unable to determine whether the power was then altered in amount. It TVRS necessary as will be readily understood to look through a large amount of the vapour in order to observe any effect on polarized light; in fact an iron tube 15 metres that is 50 feet long was employed for the experiment and unfortunately before the quantitative determina- tion was completed a burst of flame occurred and gave rise t sR 260 GIADSTONE ON CI KCULAH POT~ARIZATJOE.a conflagration which the philosopher could not extinguish without the assistance of the public. Yet while oil of turpentine is so retentive of this power its very existence in some other substances appears to depend on the manner in which they are crystal!ized. Thus silica does not show any effect on polarized light as it exists in the opal or indeed in any other form than that of quartz-crystal. fnfluence of temperature.-Just as the refrangibility of a sub-stance changes with alterations of the temperature and that not pari passu with the change of density so also the amount of rotatory power varies under like circumstances There are how-ever great differences between one substance and another in this respect.Quartz shows an increased power of rotating the plane of polarization when it is heated and that to the extent of 108" or 109.5' for an elevation of 70° C. of temperature. This crystal is known to expand by heat differently in the direction transverse tct what it does in that parallel to its axis. Tartaric acid is similarly affected and that to such an extent that Biot found himself able by reducing the temperature actually to reverse the direction of the rotation in solid amorphous tartaric acid the right-handed deviation diminishing becoming nil and the left-handed commencing before the thermometer sank to 3°C.Grape-sugar in solution is much effected by changes of tem- perature; and in saccharimetry by means of polarized light account must be taken of this circumstance. Clerget,* who has studied this subject finds that the power of rotation decreases-not increases-as the temperature rises and that according to the quantity of sugar quite irrespective of the pro- portion of' water; indeed it is the same whether 100 parts of water dissolve 1 or 130 parts of sugar. He found the decrease between 10' C. and 35' C. to be in the proportion of very nearly 100 to 91 Wilhelrny has determined it for a much longer range of temperature and deduced the formula D' = D [I -0.012 (t' -t)] in which D and D' represents two amounts of rotation corre-sponding with the temperatures t and t'.* Ann. Ch. Phys. [3] xxvi 175. GLADSTONE ON CXRCULAR POLARTZATION. Salts of quinine and many other substances are also known to vary in their power of rotating a ray of polarized light according to the temperature. Yet on the other hand it is stated that the essential oil of turpentine has exactly the same power at 55"C. as at 10" C. and even when frozen. In$uence of Magnetism or Ekctricity .-I cannot help alluding to the beautiful discovery of Faraday that a polarized ray passing through optically inactive bodies may be caused to rotate by the magnetic or electric force and that the rotation in active bodies such as oil of turpentine may be altered or even reversed at will.This part of the subject however I must not pursue further as it belongs purely to the domain of physics. In@xence of SaZution.-S ubstances which exhibit circular polari- zation are affected by solution in three different manners. 1st. There are substances as chlorate of soda bromate of soda and the double acetate of uranic oxide and soda the crystals of which exhibit evidences of circular polarization but are perfectly inactive when dissolved iu water.* These bodies like quartz appear to owe this property to the manner in which their molecules are arranged in the crystals. 211d. There are other substances all of them organic which exhibit the same polarizing power whether they are in the solid state or dissolved in some optically neutral solvent such as water or alcohol.This cannot generally be determined as in most crystals of such bodies the phenomena of circular polarization are masked by the double refraction ; but barley-sugar " has been found to have the same or nearly the same power of rotation as the sugar when dissolved in water; and it has been recently shown that whatever the amount of water in which it is dissolved the rotatory power of sugar is rigorously constant.$ Oil of turpentine belongs to this class. In such cases the substances seem to owe their power of rotating the plane of polarization to the very structure of their molecules. 3rd. There are other substances in which the result partakes to * Marbach Ann.Ch. Phys [3] xliii 252 xliv 41. Biot confirms and draw philosopliical deductions from these experiments. 9 Arndtzen Ann. Ch. Phya. 1311 iv 403. GLADSTONE ON CIRCULAR POLdlCI ZATIONs a certain extent of both these characters where indeed it would seem that the individual action of the molecules is accompanied in the solid state by another action arising from their regular arrangement. Thus sulphate of strychnine* evaporated at a temperature of between 10' C. and 20' C. gives 3 salt which contains 13 atoms of water. It crystallizes in the system of the rectangular prism with a square base and is of such a form as to allow the recognition of the circularly polarizing power. It rotates the ray in fact to about half the extent that left-handed quartz does; but the solution of sulphate of strychnine in water though it also rotates the plane does so only to ,hth or -&th part of the extent to which these crystals do.Tartaric acid when obtained in a transparent solid amorphous state by mixing it with boracic acid was found to exhibit circular polarization ; but different proportions of water cause very re-markable and as yet unexplained differences in the optical character of a solution of tartaric acid. The plane of polarization of the green rays is in fact caused to deviate more than that of any other colour and Arndtzen who has worked out the whole of this matter with much care and ability found when operating with ordinary (that is right-handed) tartaric acid dissolved in alcohol instead of water that he could obtain a left-handed rotation for the blue rays.The same observer found in reference to camphor dissolved in alcohol that the rotatory power augments with the refrangibility of the rays more rapidly than in the case of most active bodies and that the rotatory power decreases regularly with the concentration of the so1ution.f- Influence of Chemical Combination or Substitution.-In most cases this property appears to be so intimately connected with the structure of the molecule itself that it is unaffected or little affected by chemical changes of an important character. Thus an optically active acid such as tartaric acid will carry its rotatory power into its salts; and similarly an optically active base such as quinine will exhibit the phenomena of circular polarization when combined with inactive acids.From observa-tions on neutral and bitartrate of potash and ammonia which are isomorphous Past cur$ has drawn the conclusion that when * Descloizeaux Ann. Ch. Phys. [3j li 361 1. Ann. Ch. Phjs. [3] liv 403. Biot had experimented on these matters pre-viously ; Bee Ann. Ch. Phys. [3] xxxvi 257 405. : Inst. 1850 339. GLADSTONE ON CIltCULAR POLARIZATION. quantities of isomorphous substances corresponding to the equi- valents are dissolved in equal quantities of water these solutions rotate the plane of polarization to an equal degree. But it must not be supposed that as a general rule the optically inactive base or acid exerts no modifying influence on the phenomena exhi- bited by the active element with which it is combined.A glance at the above quoted table of Wilhelmy will show that it is otherwise Bouchardat* has given numbers which indicate that the combination of camphoric acid with soda or with ammonia reduces its rotatory power; some malates have a positive others a negative rotation; and as a further example asparagine if dissolved in pure water or in alkalis turns the plane of polarization to the left but if in mineral acids it turns it to the right.? Oxidation even does not necessarily destroy this power for camphor retains it when it; has been oxidized into the camphoric acid just alluded to; nor does the substitution of a compound radicle for hydrogen as is shown by the optical properties of camphovinicf and camphomethylic acids 0 The conversion of an acid into an amide and that again into the corresponding amidogen-acid is not even fatal to the retention of this optical power as is evidenced by the activity not only of tartaric acid but also of tartramide and tartramic acid; and in a parallel manner not only of malic acid but also of malarnide and mdamic acid- that is asparagine and aspartic acid.11 It must however be supposed in reference to every circularly polarizing substance that there is some amount of chemical change which the molecule cannot suffer without losing this property.In the case of the two acids just mentioned tartaric and malic we find this point passed when by the action of heat they are converted into other acids with evolution of part of their con- stituent elements for pyrotartaric fumaric and maleic acids have no effect on the polarized beam.t And here must be men- tioned one of Past eur’s remarkable observations.From fumarate of ammonia which is inactive aspartic acid may be produced ; but this unlike ordinary aspartic acid is itself inactive ;and again from this may be reproduced malic acid which also in its turn unlike * Comp. rend. xxviii 319. 9 Pasteur Ann. Ch. Phys. [3] xxxi 67. $ Malaguti. 4 Loir Ann. Ch. Phys. [S] xxxviii 483. 11 Pasteur Ann. Ch. Phys. 131 xxxviii 437. Ti Ibid xxxi 67. that derived directly from the plant has no influence 011 the polarized beam.* As yet we have no evidence that an optically active substance has ever been artificially prepared from one that is optically inactive though such is constantly occurring in nature.The tartaric acid which Liebig has very recently prepared has been found to rotate the plane of polarization like natural tartaric acid,? but then it must be borne in mind that it was prepared from milk-sugar which is itself endowed with this property. It will be interesting to determine whether the tartaric acid which Perkin and Duppa have just succeeded in preparing from succinic acid exhibits this power for succinic acid 8s yet is not classed among those bodies which display it. Xet from its analogy to tartaric and malic acids it would appear highly probable that succinic acid should rotate the polarized beam.A specimen said to have been prepared from stearic acid was found by me to be perfectly intctive; but it is quite possible that the succinic acid prepared from malic acid or that which Dessaignesi announces he has prepared from tartaric acid may prove capable of rotating a ray of light. The mutual relationship of the substances here referred to wilt be readily understood by a reference to the following tabl: C=S; 0=8 C=12; 0=16 Tartaric acid . . 2H0.C,H40, C4H606 Malic acid . . 2H0.C8H,0 C4H60 Succinic acid . . 2HO.CSH4o6 C4H6O4 Tartramide . * C8H8N208 C4H8N204 Asparagine . ’ C8H8N206 C4H8N203 Tartramie acid . HO.CsHGK09 C4N,XO5 Aspartic acid . . H0.CsH6N0 C4H,N0 Pyrotartaric acid . H0.C6H30 C3H40 Fumaric acid .2HO.C,H,O6 C4H464 Maleic acid . . 2H0.c,H206 C4H4O4 Relation between Crystalhe Form and the power of Circular Polarization.-As far back as 1820 Herschel found that the crystals of right-handed and of left-handed quartz differ in form a& from the inclination of certain facets he was able to forctel *. Ann. Ch. Phgs. [3] xxxiv 30. .i. Uohn Ann. Ch. Pharni,,Jim 1S60. $ Compt. rend. April 16 1860. GLADSTONE ON CIRCULAR POLARIZATION what would be the direction of the rotation in any particular specimen;* but it was reserved for Pasteur to show that this relation between the crystalline form and the rotatory power is one that generally obtains. It is well known that the law of symmetry does not hold good in all crystals.These exceptional forms have been termed hemi- hedral. It will sometimes happen also that a substance will crj-stallize in two forms which are both unsymmetrical but unsym- metrical in opposite directions-that is to say the one form will appear identical with the other only when it is seen reflected in a mirror. They differ in fact in the same way as one side of our face differs from the other or as our two hands differ. These are variously called not superposable incongruous or opposite hemihedra. From an observation of the opposite hemihedral character of crystals of the double racemate of' soda and ammonia Pasteur commenced that series of observations which led him to the discovery that racemic acid is composed of two tartaric acids with opposite but equal powers of polarization conjoined together as one substance ; to the isolation of left-handed tartaric acid ; to the artificial preparation of racemic acid; and of a neutral and unresolvable tartaric acid$-discoveries which however interesting I refrain from dwelling on as the papers in which they are explained have been printed in our Quarterly Journal and are well known to chemists in this country.The same philosopher has shown by a great number of in- stances that when a substance crystallizes in opposite hemihedra it indicates the existence of two opposite powers of rotation and that active and inactive bodies will not crystallize together however isomeric.2 Yet it cannot be laid down as a universal law that this property of matter in a crystalline state is always accompanied with the power of circular polarization for formate of stroiitia gives opposite hemihedra but neither kind of crystal when separated from the other and dissolved has any influence on polarized light.§ Sulphate of magnesia is an analogous instance.Nor on the otlier hand can it be affirmed that this * See his remarks on this subject in his article on Light in the Encgc. Metrop. par. 1042 in which he almost prophecies more recent discoveries. .t. Ann Ch. Phys. (31 xxiv 442 ; xxviii 56 and Compt. rend. xxxvii 162. .inn. Ch. Phys. [3J xxxviii 437. 3 Illid xxxi 67. GLADSTONE ON CIRCULAR POLARIZATION. optical property is necessarily connected with the power of forming such crystals; for two sulphamylic acids have been discovered which are isomeric and absolutely identical in the crystalline form of their salts vithout showing any disposition to form hemihedra and yet the one is active and the other inactive.* The inactive aspartic acid derived from fumarate of ammonia does not crystallize in hemihedra as the ordinary aspartic acid does; and similarly there are some differences in the crystalline forms of the salts of the natural or active and of the artificial or inactive malic acid.Marbach? has observed that though chlorate of soda crystal- lizes in opposite hemihedra and in that condition exercises an influence on the polarized beam yet a solution of either right- handed or left-handed crystals alone is perfectly inactive and the salt crystallizes out from such a solution in both farms instead of that only from which it was made.POLARIZATION INQUIRIES. CIRCULAR AS APPLIED TO CHEMICAL The phenomena of circular polarization have been applied to many practical purposes in chemical research. These may be conveniently grouped under three heads-the quantitative estima- tion of certain organic products; the determination of what is going forward in a solution; and the examination of isomeric substances. 1at. Quantitative estimation of certain organic products. Curie Sugar.-As cane sugar dissolved in water rotates the ray of polarized light to an extent directly proportional to the amount of sugar in a given depth of liquid and irrespective of the amount of water or of the simultaneous presence of optically inactive substances this property is frequently made use of to effect a quantitative determination.Clerge t$ has worked out this process very fully and others$ have since somewhat extended or modified his observations. Instruments have been devised for * Compt. rend. dii 1259. .t. Ann. Ch. Phys. [3] xliv 41. $ Ibid. xxvi 175. 8 Especially Wilhelmy and Arndtzen in papers previoady referred to; Pohl Wien. Scad. Rericht xxi 492; and MichBelis Journ. Pharm. Chem. lxxv 464. GLL41)8TONE ON CIRCULAR POLARIZATION. the purpose by Biot Solei&* Savart Powell,? Leeson,$ Mitscherlich but the simplest and perhaps the most effective is a modification of Biot's apparatus which Mr. Heisch employs and has kindly lent me on this occasion.It consists essentially of three parts-a polarizer an analyser and a tube for holding the solution. The polarizer is a Nicoll's prism and plano-convex lens to rerider the rays parallel; the nnalyser consists of a small aper- ture in a brass plate a lens and an achromatic prism of doubly refracting spar and it is attached to the vernier of a graduated circle. The tube through which the polarized beam passes between the polarizer and the analyser is a narrow tube of black glass ground in the inside with coarse emery and fitted at each end with covers of perfectly parallel glass. Several such tubes of various known lengths so as to hold different quantities of liquid are provided and the position of the polarizer and analyser can be easily adapted to each.If when the index of the scale is at O" and the extraordinary image is at its greatest obscuration a solution of sugar be placed in the tube it is easy to determine how much the analyser must be now turned round in order to bring the extraordinary image again to its greatest obscuration or rather to the "sensitive tint." It is impossible here to enter into the minuti= of the apparatus or of the treatment of the solution; suffice it to say that Heisch prefers operating by lamp light and has found that it requires 6.09 per cent. of cane-sugar to produce a rotation of 1"in a depth of 1 inch hence the per- centage in the solution examined may be reckoned according to the simple formula a representing the arc of rotation and I the length in inches.An ingenious method of confirming the amount of cane-sugar in a solution or of determining it in the presence of other optically active bodies is founded on the property possessed by this sugar of being converted by acids into a sugar which exhibits the opposite or left-handed rotation. The following * The English reader will find a description of this instrnment by Dr. Bence Jones in the Pharm. Journ. and Trans. xi 455. .t. Phil. Mag. April 1843. :Mem. Chem Soc, ii 26. 268 GLADSTONE OK CIBCLTLAH POLARIZ.\TlON. formula serves for this inverted sugar according to Heisch at 15" C. p = 16,026-a I As glucose rotates the plane of polarization to the right and is not capable of inversion by acids this process will even serve to determine the respective amounts of cane-sugar and glucose if mixed together in solution.Or the same may be effected by determining the rotation of the mixed solution boiling it with potash which destroys the glucose and then again determining the rotation which is now due solely to cane-sugar. Other sugars.-Bence Jones* has published analyses of the different wines of commerce in which he determined the grape- sugar by means of Soleil's saccharimeter. Poggialef has employed a similar method for the estimation of the amount of sugar in milk. Listingf has published optical determinations of the sugar in diabetic urine. The formula of Heisch for this sugar is p = 8.346 -a I If albumin be present it must be removed as it possesses itself an influence on polarized light.A16urnin.-This substance may likewise be estimated by means of its rotating power and A. Becquerelt has in fact measured in this way the proportion of albumin contained in the serum of blood. 2nd. Determination of what is yoiny forward in a solution. The variations in the plane of polarization will often indicate changes in a solution which could not be watched by any other method or even the existence of which might never otherwise have been recognized. Thus Wilhelmp 11 investigated the action of sulphuric phos- phoric nitric and hydrochloric acids on cane-sugar and examined mathematically the progress of the change with reference to time. EIe satisfied himself that the final result of the conversion of the sugar is indcpendent of the quantity of acid originally added.* Proc. Roy. Inst. Vol. i. f Conipt rend. xxviii 505 584. 2 Anii. Cli. Pharm. xcvi 93 101. Compt. rend. xxix 625. )I Pogg. Ann. lxxxi 413 409. .. GLADSTONE ON CIRCULAR POLARIZATION. Bio t investigated a very curious state of combination between tartaric acid and boracir! acid when they are both dissolved together in water and he endeavoured to determine the nature of the transformation which tartaric acid undergoes when acted on by heat. He has applied circular polarization also more widely to the study of the question of the condition of a substance in solution. The papers* which contain these inquiries are very lengthy and include much philosophical reflection on the subject in general.Thus also from some observations of Bouchardat on the effect of polarized light on camphoric acid the same saturated with soda and then supersaturated with hydrochloric acid I was able to derive from a novel source an additional illustration of the reciprocal decomposition of binary compounds in so1utiou.t Be'ch amp 5 too from observations with the pdariscope arrived at the conclusion that crystallized starch sugar is a combination which cannot exist indefinitely except in the solid state and that when dissolved in water it loses its combined water slowly in the cold but rapidly urider the influence of heat resembling in this respect hydrated oxide of copper or hydrated oxide of iron in the presence of water.In fact he supposes that the C,2H,20,2.2H0 when dissolved passes during the lapse of a certain number of hours wholly into C H,202. 3rd. Examination of isomeric substances. Reference has already been made to the researches of Pasteur by which he unravelled the relations between racernic and tartaric acids and enriched our knowledge of many organic compounds by exhibiting isomeric bodies identical with them save in their action on polarized light and perhaps their crystalline form. Their solubility appears ah in some instances to be slightly affected. His discoveries however have not been confined to those already alluded to. Binding that there exist two sulph-amplic acids the one possessed of the rotatory power and the other not possessing it he was able by their decomposition to produce two amylic alcohols differing slightly in their physical properties.fj His very original examination of the cinchona J( *4nn.Ch. Phys. xxviii 215 351 ; xxxvi 257 405. + Chem. Soe. Qu. J. ix 148. X Compt. rend. xlii 640. Dubrunfaut differs from this explanation ibid 739; but 36ehamp defends his own view {bid 896. 5 Comp. rend. xlii 1259. 270 PROFESSORS KIRCHHOFF AND BUNSEN ON CHEMICAL alkaloids and the two isomeric groups at the head of which stand quinine and cinchonine,* I shall only just refer to as his paper was reproduced in our Quarterly Journa1.f Different isomeric essential oils of the composition C,H might be distinguished by this method but the data seem wanting for the practical application of circular polarization to the analysis of them.Berthelott has by the same agency investigated a very remarkable change that takes place in oil of turpentine or oil of lemons by the action of acids alkaline or earthy chlorides or some other salts. This isomeric modification is indicated by a reduction of the rotatory power whether positive or negative; it never entirely disappears but there are grounds for believing that the result is a mixture of unaltered oil and oil which has been rendered inactive. It is not necessary that the salt which produces this singular change should dissolve in the oil for even the insoluble fluoride of calcium has a strongly marked effect.

ISSN:1743-6893    

DOI:10.1039/QJ8611300254

出版商:RSC    

年代:1861

数据来源: RSC

摘要:

270 PROFESSORS KIRCHHOFF AND BUNSEN ON CHEMICAL XX1V.-ON CHEMICAL ANALYSIS BY SPECTRUM-OBSERVATIONS. RY PROFESSORS KIRCHHOFF AND BUNSEN. (From Poggendorff’s Annslen Bd. cx. S. 161.) is well known that many substances possess the power of developing peculiar bright lines in the spectrum of a flame into which they are introduced. This property may be made the foundation of a method of qualitative analysis which greatly enlarges the field of chemical reactions and leads to the solution of problems hitherto unapproachable. The Fright lines produced in this manner shorn themselves most plainly when the temperature of the flame is highest and its illuminating power least. Hence Bunsen’s gas-burner which gives a flame of very high temperature and very slight luminosity is well adapted for experiments on the bright lines of the flame- spectra produced as above described.The coloured plate at the end of this paper shows the spectra given by such a flame when the chemically pure chlorides of potassium sodium lithium strontium calcium and barium are it Comp. rend ,xxxvii 110. 9 Vol. vi p. 273. $ Ann Ch. Phgs. 131 xxxviii 38. AKALYSIS BY 8PECTRUM-OBSERVATIONS. volatilised in it. The ordinary solar spectrum is added by way of comparison. The potassium compound employed was obtained by igniting chlorate of potassium which had been previously recrystallized six or eight times. The chloride of sodium was prepared by neutralizing pure carbonate of sodium with hydrochloric acid and crystallizing the salt several times.The salt of lithium was purified by precipitation fourteen times with carbonate of ammonium. The purest specimen of' marble which could be obtained dissolved in hydrochloric acid was the source of the calcium salt. From this solution the carbonate of calcium was thrown down in two portions by fractional precipitation with carbonate of ammonium the latter half of the calcium salt being converted into the nitrate. The salt thus obtained was dissolved in absolute alcohol and after evaporation of the alcohol converted into the chloride by precipi- tation with carbonate of ammonium and solution in hydrochloric acid. To obtain pure chloride of barium the commercial salt was boiled out repeatedly with nearly absolute alcohol and the residual salt freed from alcohol was dissolved in water and thrown down by fractional precipitation in two portions.The second only of these portions was dissolved in hydrochloric acid and the salt still further purified by repeated crystallizations. Pure chloride of strontium was prepared by crystallizing the commercial salt several times from alcohol and by fractional pre- cipitation of the salt with carbonate of ammonium the second portion being dissolved in nitric acid and the nitrate freed from the last traces of calcium salt by boiling with alcohol. The pro-duct thus purified was lastly thrown down with carbonate of ammonium and the precipitate dissolved in hydrochloric acid. All these various purifications were conducted as much as possible in platinum vessels.The apparatus which we have usually cmployed for our spectrum-observations is represented in the annexed woodcut. A is it box blackened on the inside having its horizontal section in the form of a trapezium and resting on three feet; the two inclined sides of the box which are placed at an angle of about 58O from each other carry the two small telescopes B and C. The eye-piece of the first telescope is removed and in its place is inserted a plate in which a slit made by two brass knife-edges is so arranged that it coincides with the focus of the object-glass. The gas-larnp D stands before the slit in a position such that the mantle of the flame is in a straight line with the axis of the telescope B. Some-what lower than the point at which the axis of the tube produced meets the mantle the end of a fine platinum wire bent round to a hook is placed in the flame.The platinum wire is supported in 272 PROFESSORS KIRCH~TOFFAND BUNSEN ON CIZEMICAL this position by a small holder E and on to the hook is melted a globule of the dried chloride which it is required to examine. Between the object-glasses of the telescopes B and C is placed a hollow prism Fg filled with bisulphide of carbon and having a refracting angle of 60'. The prism rests upon a brass plate move- able about a vertical axis. The axis carries on its lower part the mirror G and above that the arm Hi which serves as a handle for turning the prism and mirror. A small telescope placed some way off is directed towards the mirror and through this telescope an image of a horizontal scale fixed at some distance from the mirror is observed.By turning the prism round every colour of the spectrum may be made to move past the vertical wire of the telescope C and any required position in the spectrum thus brought to coincide with this vertical line. Each particular portion of the spectrum thus corresponds to a certain point on the scale. If the luminosity of the spectrum is very small the wire of the telescope C may be illuminated by means of a leas which throws a portion of the ray3 fiom a Inmp throiigh a small opening in the side of the tube of the telescope C. We have compared the spectra represented 011 the Plate which were obtained from the pure chlorides with those produced when the bromides iodides hydrates sulphates and carbonates of the several metals are brought into the following flames :-Into the flame of sulphur., , bisulphide of carbon. , , aqueoiis alcohol. Into the non luminous flame of coal gas. Into the flame of carbonic oxide. , , hydrogen. Into the oxyhydrogen flame. As the result of these somewhat lengthy experimerits the details of which m7e here omit it appears that neither the alteration of ANA EY SIS BY SPECTRUM-ORSERVATIO his. the bodies with which the several metals may be combined nor the variety of the chemical processes occurring in the several flames nor the wide differences of temperature which these flames exhibit produce any efect upon the position of the bright lines in the spectrum which are characteristic of each metal.The following considerations show how much the temperature of these various flames differ. An approximation to the tempera- ture of a flame is obtained by help of the equation. t=Bgzu, ZPS in which t signifies the required temperature of the flame g the weight of one constituent of substance burning in oxygen ‘10 the heat of combustion of this constituent p the weight and s the specific heat of one of the products of combustion. The heat of combustion of the following bodies may be taken as-Sulphur ................. 224OOC. Bisulphide of carbon.. ..... 3400 Hydrogen.. .............. 34462 Marsh-gas.. .............. 13063 Ethylene................. 11640 Biitylene................. 11529 Carbonic oxide ........... 2403 The specific heats under constant pressure were fomd by Regnault to be- Sulphurous acid = 0.1553 Carbonic acid = 0,2164 Nitrogen = 0’2440 Aqueous vapour = 0’4750 Hence the temperatures of the flames are found to be- The sulphur flame.. .................. 1820°C. The bisulphiile of carbon flame. ........ 2195 The coal-gas flame*. .................. 2350 The carbonic oxide flame+. ............ 3042 The hydrogen flame in air$. ........... 3259 The oxyhydrogen flames .............. 8061 It was found ghat the same metallic compound placed in one of these flames gives a more intense spectrum the higher the tempe- rature of the flame. In the same flame those compounds of a metal give the brightest spectra which are most volatile.In order to prove stillmore conclusively that each of the above- mentioned metals always produces the same bright lines in the spectrum we have compared the spectra represented in the Plate with those produced when the electric spark passes between electrodes made of these metals. Small pieces of sodium potassium lithium strontium and calcium were fastened to fine platinum wires and melted two by * Ann. Ch. Pharm. cxi. 258. -f J3iinsen’s ‘Casometry.’ p. 242. $ Ibid. B bid. rr 274 PROFESSORS ItIRCEfHOFF AND BUXSlTh' ON CIIEJYIC'AL two into glass tubes so that the pieces of metal were separated by about 1to 2millims. and the platinum wires were melted through the sides of the glass tubes.Each of these tubes was placed in front of the spectrursn-instr.ument and by means of a Ruhn?korff's induction apparatus sparlrs were allowed to pass betwsen the pieces of metal inside the tube ; the spectritm thus produced v7as then compared with that given by a gas.fiame into which the chloride of the metal was brought. The flame was placed behind the glass tube. By alternately briaging the incluction apparatus into and out of action it was cmy without measuring to convince onaclves that in the brilliant spectrum of the electric spark the bright lines of the fiame-spectrum were present in their normal position. Besides these lines other bright ones appeared in the eIectric spark spectrum ; some of these were produced by foreign metals present in the electrodes ; others arose from nitrogen which filled the tubes after the oxygen had combined with a portion of the electrodes.From these facts it appears certain that the appearance of the bright lines represented in the spectra on the Plate may be regarded as absolute proof of the presence of the particular metal. They serve as reactions by means of which these bodies may be recognized with more certainty greater quickness and in far smaller quantities than can be done hy help of any other knom7n analytical method. The spectra drawn on the Plate represent those seen when tlie slit was of such a width that only tlie most conspicuous of the lines of the solar spectrum were visible tlie magnifying power of the telescope C being a fourfold one arid the light of a moderate degree of intensity.These circumstances seem to us to be the most advantageoils den it is requircd to make a chemical analysis by means of spectrum-observations. The appearance of the spec- trum may under other conditions be essentially different. If the purity of the spectrum be increased many of those lines which appeared before as single ones are split up into several; thus the sodium line is divided into two separate lines. If on the other hand the intensity of the light be increased new lines appear in several of the spectra and the relative brichtness of the old ones becomes altered. In general an indistiuct line becomes brigliter upon increasing the illumination more rapidly than it brighter line but not to such an extent that the indistinct line ever overtakes the brighter one in intensity.A good example of this is seen in the two lithium lines. We have observed only * On employing on one owasion with strontium-electrodes a tube filled with hydrogen instead of nitrogen the stream of sparks changed rapidly into a continuous arc of light whilst a grey pellicle covered the inside of the tube. The tube was opened under rock-oil when it was found to tie cmpty the hydrogen having disap- penred. This gas appears at thc enormously high temperature of the electric spark Lo hare dccornposeci the oxide of strontium which was not completely removed from the metal. ANALYSIS BY SrECTRUM-OBSERVATIONS. one exception to this rule namely in the line Ba 7 which by light of small intensity is scarcely visible whilst Ba y appears plainly but by light of greater intensity becomes more visible than the latter.We intend on a future occasion to examine this poiut in detail. We now proceed to describe the peculiarities of the several spectra tlie exact acquaintance with which is of practical import- ance and to point out the advantages which this new method of chemical analysis possesses over the older processes. Sodium. The spectrum-renction of sodium is the most delicate of all. The pellow line Na a the only one which appears in the sodium spectrum is coincident with Fraunhofer’s dark line D and is remarkable for its exactly defined form and its extraordinary brightness.If the temperature of the flame be very high and the quantity of the substance employed very large traces of a continuous spectrum are seen in the immediate neighbourhood of the line. In this case too the weaker lines produced by other bodies when near the sodium line are discerned with difficulty and are often not seen till the sodium reaction has almost subsided. The reaction is most visible in the sodium-salts of oxygen chlorine iodine bromine sulphuric acid and carbonic acid ; but it is always evident even in the silicates borates phosphates and other non- volatile salts. Swan* has already remarked upon the small quantity of sodium necessary to produce the yellow line. The following experiment shows that the chemist possesses no reaction which will bear the remotest comparison as regards delicacy with this spectrum-analytical determination of sodium.In a far corner of our experiment room the capacity of which was about 60 cubic metres we burnt a mixture of 3 milligrammes of chlorate of sodium with milk-sugar whilst the non-luminous flame of the lamp was observed through the slit of the telescope. Within a few minutes the flame which gradually became pale yellow gave a distinct sodium line lastiug for ten minutes and then entirely disappearing. From thc weight of sodium salt burnt and the capacity of the room it was easy to calculate that in one part by weight of air there was suspended less than 2+m of a part of soda-smoke. As the reaction can be quite easily observed in one second and as in this time the quantity of air which is heated to ignition by the flame is found from the rate of issue and froin the composition of the gases of the flame to be only about 50 cub.cent. or 0.0647 grm. of air containing less than ‘k0 of sodium salt it folloms that the eye is able to detect 4 * Trans. Roy. SOC.Edinb. vol. xxi. Part 111. p. 411. T2 276 PROFESSORS HIRCHHOFF AND BUNSEN ON CHENICAZ with the greatest ease quantities of sodium salt less than +m of a milligramme in weight. With a readion so delicate it is easy to understand why a sodium reaction is almost always noticed in ignited atmospheric air. More than two-thirds of the cart h’a surface is covered with a solution of chloride of sodinm fine particles of which are continually being carried into the air by the action of the waves.The particles of sea-water thus cast into the atmosphere evaporate leaving almost inconceivably small ivsidues which floating about are almost always present in the air and are rendered mident to our eyesight in the sunbeam. These minute particles perhaps serve to supply the smaller organ-ized bodies with the salts which larger animals and plants obtain from the ground; but there is also another point of view in which the presence of this chloride of sodium in the air is of interest. If, as is scarcely doubtful at the present time the explanation of the spread o€ contagious disease is to be sought for in some peculiar eontact-action it is possible that the presence of an antiseptic substance like chloridc of sodium eveii in almost infinitely small quantities may not be without influence upon such occurrences in the atmosphere.By means of daily and long-continued spectrum observations it would be easy to discover whether the alteration of intensity in the line Na a produced by the presence of sodium-compounds in the air has any connection with the appearance ad direction of march of an endemic disease. The unexampled delicacy of the sodium reaction explains also the well-observed fact that all bodies after a lengthened exposure to air show the sodium line when brought into a flame and that it is only in a few salts that it is possible to get rid of the last traces of the line Na a,even after repeated crystallization from water which has only been in contact with platinum.A thin platinum wire freed by ignition from every trace of sodium salt shows the reaction most visibly after a few hours’ exposure to the air. In the same way the dust which settles from the air in a room shows the bright line Na a to render this evident it is only necessary to knock a dnsty book for instance at a distance of some feet from the flame when a wonderfdly bright flash of the yellow band is seen. Lithium. The luminous ignited vapour of the lithium compounds gives two sharply defined lines the one a very weak yellow line Li 8 and the other a bright red line Li a. This reaction likewise exceeds in certainty and clelicacy all ordinary methods of ana- lytical research.It is however not quite so sensitive as the sodium reaction only perhaps because the eye is more adapted to distinguish yellow than red rays. When 9 milligrammes of carbonate of lithium mixed mit h excess of milk-sugar were burnt the reactioii Raq visible in a room of 60 cubic metres capacity. AN.\LYSIS BY STECTRU~i-OBSERVATIONS. Hence by the method already explained we find that the eye is capable of distinguishing with absolute certainty a quantity of carbonate of lithium less than +w of a milligramme in weight 0.05 grm. of carboi'ate of' lithiuin salt burnt in the same room was su6cient to enable the ipited air to show the red line Li a for art hour after the combustion had taken place. The compounds of lithium with oxygen iodine bromine and chlorine are the most suitable for the purpose; still the carbonake sulphate and even the phosphate give almost as distinct a reaction.Minerals containing lithium such as triphylline triphane petalite kpidolite require only to be held in the flame in order to obtain the bright lirie Li a in the most satisfactory manner. In this way the presence of lithium in many felspars can be directly shown as for instance in the orthoclase from Baveno. The lirie is seen for a few moments only directly after the mineral is brought into the flame. In the same way the mica from Altenberg and Penig was found to contain lithium whereas micas from Miask Ashaffen- burg Modum Bengal Pennsylvania &c. were found to be free from this metal.In natural silicates which contain only small traces of lithium this metal is not observed so readily. The examination is then best conducted as follows :-A small portion of the substance is dipted and evaporated with hydrofluoric acid or fluoride of ammonium the residue moistened with sulphuric acid and heated the dry mass being dissolved in absolute alcohol. Tlie alcoholic extract is then evaporated the dry mass again dissolved in alcohol and the extract allowed to evaporate on a shallow glass dish. The solid pellicle which remains is scraped off with a fine knife and brought into the flame upon the thin p€atinum wire. For one experiment &-of a milligramme is in general quite a sufficient quantity. Other compounds besides the silicates in which small traces of lithium require to be detected are transformed into sulphates by evaporation with sulphuric acid or otherwise and then treated in the manner described.In this way we arrive at the unexpected conclusion that lithium is most widely distributed throughout nature occurring in almost all bodies. Lithium was easily detected in 40 cubic centimetres of the water of the Atlantic Ocean collected in 41' 41' N. lati-tude and 39" 14' W. longitude. Ashes of marine plants (kelp) driven by the Gulf-stream on the Scotch coasts contain evident traces of this metal. All the orthoclase and quartz from the granite of the Odenwald which we have examincd contain lithium. A very pure spring water from the granite in Schlierbach OD the west side of the valley of the Neckar was found to contain lithium whereas tile water from the red sandstone which supplies the Heidelberg laboratory was shown to contain none of this metal Mineral waters in a litre of which lithium could hardly be detected by the ordinary methods of analysis gave plainly the line Li a even if only a drop of the water on a platinum wire was 278 PROFESSORS KIRUHHOFF AND BUNSEN ON CIIEMICAL brought into the flame.* All the ashes of plants growing in the Odenwald on a granite soil as well as Russian and other potashes contain lithium.It was found also in the ashes of'tabacco of vine leaves of the wood of the vine and of grapes,? as well as in the ashes of the crops grown in the Rhine-plain near Waghausel Deidesheim and Heidelberg on a non-granitic soil.The milk of the animals fed upon these crops also contains 1itfiium.f It is scarcely necessary to say that a mixture of volatile sodium and lithium salts gives the reaction of lithium alongside that of sodium with a scarcely perceptible diminution of precision and distinctness. The red lines of the former substance are still plainly seen wlien the bead contains part of lithium salt and when to the naked eye the yellow soda-flame appears untinged by the slightest trace of red. In cotisequence of the somewhat greater volatility of the lithium salt the sodium reaction lasts longer than that of the other metal. In those cases therefore in which small quantities of lithium have to be detected in presence of large quantities of sodium the bead must be brought into the flame whilst the observer is looking through the telescope.The lithium lines are often seen only for a few moments amongst the first products of the volatilization. In the production of lithium salts on the large scale in the proper choice of a raw material and in the arrangement of suitable methods of separation this spectrum-analysis affords most valuable aid Thus it is only iiecessary to place a drop of mother-liquor fmm any mineral spring in the flame and to observe the spectrum produced in order to show that in many of these waste products a rich and hitherto unheeded source of litliiurn salts exists. In the same way during the course of the preparation any loss of lithium in the collateral products and residues can be easily traced and thus more convenient and economical methods of preparation may be found to replace those at present employed.$ Potassiuna.Volatile potassium compounds give when placed in the flame a widely extended continuous spectrum which contains only two characteristic lines namely one line ICa a in the outermost red * When liquids have to be brought into the flame it is best to bend the end of the platinum wire of the thickness of a horsehair to a small ring and to beat this ring flat. If a drop of liquid be brought into this ring enough adheres to the wire for the experiment. j-In the manufactories of tartaric acid the mother-liquors contain so much fith'um salts that considerable quantities can thus be prepared.$ Dr. Folwarczny has been able by help of the line Li a to detect lithium in the ash of human blood and of muscular tissue. 3 Ke obtain by such an improved method from two jars (about 4 litres) of a mother-liquor from a mineral spring which by evaporation with sulpburic acid gave 1h-2 of residue half an ounce of carbonate of lithium of the purity of the commercial the cost of which is about 140 florins the pound. A great number of other mineral- spring mot!ier-liquors which we examined showed a similar richness in compounds of lithium. ANALYSIS BY SPECTRW M-OBSEBVATIONS. approaching the ultra-red rays exactly coinciding with the dark line A of the solar spectrum and a second line Ka p situated far in the vioiet rays towards the other end of the spectrum and also identical trritli a particular dark line observed by Fraunhofer.A very indistinct line coinciding with Fraunhofer’s line B which however is seen only when the light is very intense is not by any means so characteristic. The violet line is somewhat pale but can be used almost its well as the red line for the detection of potassium. Owing to the position of these two lines both situated near the limit at which our eyes cease to be sensitive to the rays this reaction for potassium is not so delicate as the reaction for the two metals already mentioned. It became visible in the air of our room when one granime of clilorate of potassium mixed with milk-sugar was burnt. In this way therefore the eye requires the presence of r$m of a milligramme of chlorate of potassium in order to detect the presence of potassium.Caustic potash and all compounds of potassium with volatile acids give the reaction without exception. Potash silicates and other non-volatile salts on the other hand do not produce the reaction by themselves unless .the metal is present in very consi- derable quantity ; when however the amount of potassium is smaller it is merely necessary to melt the substance with a bead of carbonate of sodium. The presence of the sodium does not in the least interfere with the reaction and scarcely diminishes its delicacy. Orthoclase sanidine and adularia say in this way be easily distinguished from albite oligoclase Labradorite and anorthite. In order to detect the smallest traces of potassium salt the silicate requires only to be slightly ignited with a large excess of fluoride of ammonium on a platinum capsule after which the residue is brought into the flame on a platinum wire.In this way it is found that almost every silicate contains potassium. Salts of lithium diminish or influence the reaction as little as sodium salts. Thus we need only to hold the end of a burnt cigar in the flame before the slit in order at once to see the yellow line of sodium and the two red lines of potassium and lithium this latter metal being scarcely ever absent in tobacco ash. Strontium. The spectra produced by the alkaline earths are by no means so simple as those produced by the alkalies. That of strontium is especially characterized by the absence of green bands.Eight lines in the strontium-spectrum are remarkable namely six red one orange and one blue line. The orange line Sr a whiclt appears close by the sodium line towards the red end of the spectrum the two red lines Sr and Sr y and lastly the blue line Sr 6 are the most important strontium bands both as regafds their position and their intensity. To examine the interlsity of 280 PBOFESSORS RIRCHHOFE AND SUX'SEN ON CHEMICAL the reaction we quickly heated an aqrieous solution of chloride of strontium of known concentration iu a platilium dish over a large flame till the water was evaporated and the basin became red-hot. The salt then began to decrepitate and was thrown up into the air in microscopic particles in the form of a white cloud.On weighing the residual salt it mas found that in this way 0.077 grm. of chloride of strontium had been mixed in the form of a fine dust with the air of the room weighing 77000 grms. As soon as the air in the room was perfectly mixed by rapidly moving an open urn brella the characteristic lines of the strontium-spectrum were beautifully seen. According to this experimeiit a quantity of strontium may be thus detected equal to the &m part of a milligramme in weight. The chloride and the other haloicl salts of strontium give the best reaction. The hydrate and carbonate of strontium give it much less vividly the sulphate still less whilst the com-pounds of strontium with the non-volatile acids give either a very slight reaction or none at all.Hence it is well first to bring the bead of substance alone into the flame and then again after moist- ening with hydrochloric acic?. If it be supposed that sulphuric acid is present in the bead it must be held in the reducing part of the flame before it is moistened with hydrochloric acid for the purpose of changing the sulphate into the sulphide which is decomposed by hydrochloric acid. To detect strontium when combined with silicic phosphoric horacic and other non-volatile acids it is best to proceed as follows:-Instead of fusing with carbonate of sodium in a platinum crucible a conical spiral of platinum wire is employed; this spiral is heated to whiteness in the flame and dipped while hot into finely-powdered dried carbonate of sodiutn which should contain so much water that a sufficient quantity adheres to the wire when it is once dipped into the salt.The fusion takes place in this spiral much more quickly than in a platinum crucible as the mass of platinum requiring heating is small and the flame comes into direct contact with the salt. As soon as the finely-powdered mineral has been brought into the fused soda by means of a small platinum spatula and the mass retained above the melting point for a few minutes the cooled mass has only to be turned upside down and hocked on thc porcelain plate of the lamp in order to obtain the salt in a large coherent head. The fused mass is covered with a piece of writing paper and then broken by pressing it with the blade >f a steel spatula until the whole is reduced to a fine powder.The powder is brought to one spot on the edge of the plate and care- fully covered with hot water which is allowed to flow backwards and forwards over it so that after decanting and rewashing the powder several times all the soluble salts are extracted without losing any of the residue. If a solution of chloride of sodium be employed instead of water the operation may be conducted mom rapidly and with greater security. The insoluble salt contains the strontium as carbonate; and one or two tenths of a milligramme of the substance brought on to the wire and moistened with hydrochloric acid is sufficient to produce the most intense reaction. It is thus possible without help of platinum crucible mortar evaporating basin or funnel and filter to fuse powder digest and wash out the substance in the space of a few minutes.The reactions of potassium and sodium are not influenced by the presence of strontium. Lithium also can be easily detected in presence of strontium when the proportion of the former metal is not very small The lithium line Li a appears as an intensely red sharply defined band upon a less distinct red ground of the broad strontium band Sr p. Calcium. The spectrum produced by calcium is immediately distiiiguislied from the four spectra already considered by the very characteristic bright green line Ca 6. A4second no less characteristic feature in the calcium spectrum is the intensely bright orange line Ca a,lying considerably nearer to the red end of the spectrum than either the sodium line Na a or the orange band of strontium Sr a.By burning a mixture consisting of chloride of calcium chlorate of potassium and milk-sugar a white cloud is obtained which gives the reaction with as great a degree of delicacy as strontium salts do under similar circumstances. In this way it was found that &m of a milligramme in weight of chloride of calciuni can be detected with certainty. Only the volatile compounds of calcium give this reaction; the more volatile the salt the more distinct and delicate does the reaction become. The chloride bromide and iodide of calcium are in this respect the best compounds. Sulphate of calcium does not produce the spectrum till it has become basic but then very brightly and continuously.In the same way the reaction of the carbonate becomes more distinctly visible after the carbonic acid has been expelled. Compounds of calcium with the non-volatile acids remain inac- tive in the flame; but if they are attacked by hydrochloric acid the reaction may easily be obtained as follows A few milligrammes of the finely powdered substance are placed on the moistened flat platinum ring in the moderately hot portion of the flame so that the powder is fritted but not melted on to the wire; if a drop of hydrochloric acid be now allowed to fall into the ring so that the greater part of the acid remains hanging to the wire and if the wire be then brought into the hottest part of the flame the drop evaporates in the spheroidal state without ebullition.If the spec- trum of the flame be observed during this operation it will be noticed that at the moment when the last particles of liquid evaporate a bright calcium spectrum appears. If the quailtitics of the metal present are very small the characteristic lines are 282 PROFESSORS KIRCHHOFF AND BUNSEN ON CHEXICAZ seen for a moment only; if larger quantities are contained the phenomenon lasts for a longer time. It is only in silicates which are decomposed by hydrochloric acid that the calcium can be thus detected. In those minerals which are not attacked by that acid the examination is best made as follows. A few milligrammes of the substance under examina- tion in a state of fine division are placed upon a flat platinum lid together with about a granme of fluoride of ammonium and the mixture is gently ignited until all the fluoride is volatilized.The slight crust of salt remaining is moistened with a few drops of sulphuric acid and the excess of acid removed by heat. If about a milligramme of the residual sulphates be scraped together vith a knife and brought into the flame the characteristic spectra of potassium sodium and lithium supposing these three metals to be present are first obtaiued either simultaneously or consecutively. If calcium and strontium be also present the corresponding spectra generally appear somewhat later after the potassium sodium and lithium have been volatilized.When only traces of strontium and calcium are present the reaction is not always seen; it becomes however immediately apparent on holding the bead for a few moments in the reducing flame then moistening it with hydro- chloric acid and again bringing it into the flame. These easy experiments such as either heating the specimen alone or after moistening with hydrochloric acid or after treating the powder with fluoride of ammonium either alone or in presence of sulphuric or hydrochloric acid provide the mineralogist and geologist with a series of most simple methods of recognizing the components of the smallest fragment of many substances (such for instance as the double silicates containing lime) with a cei tainty which is attained in an ordinary analysis only by a large expen- diture of time and material.The following examples will illustrate this statement. 1. A drop of sea-water heated on the platinum wire shows at first a strong sodium reaction ;and after volatilization of the chloride of sodium a weak calcium spectrum is observed which on moistening the wire with hydrochloric acid becomes at once very distinct. If ft few decigrammes of the residual salts obtained by the evaporatiou of sea-water be treated in the manner described under lithium with sulphuric acid and alcohol the potassium and lithium reac- tions are obtained. The presence of strontium in sea .water can be best detected in the boiler-crust from sea-going steamers. The filtered hydrochloric acid solut#ion of such a crust leaves on evapo- ration and subsequent treatment with a smsll quantity of alcohol a residue slightly yellow-coloured from basic iron salt which is deposited after some days and can then be collected on a small filter and Fvashed with alcohol.The filter burnt on a fine platinum wire and held in the flame gives besides the calcium lines an intensely bright strontium spectrum. ANALYSIS BY SPECTRUM-OBPERVATIONS. 283 2. Mineral waters often exhibit the reactions of potassium sodium lithium calcium and strontium by mere heating. If for example a drop of the Diirkheim or Kreuznach water be brought into the flame the lines Na a Li a Ca a and Ca p are at once seen. If instead of using the water itself a drop of the mother- liquor be taken these bands appear most vividly.As soon as the chlorides of sodium and lithium have been to a certain extent volatilized and the chloride of calcium has become more basic the chzracteristic lines of the strontium spectrum begin to show them- selves and continue to increase in distinctness until at last they come out in all their true brightness. In this case therefore by the mere observation of a single drop undergoing vaporization the complete analpis of a mixture containing five coustituents is per-fomned in a few seconds. 3. The ash of a cigar moistened with hydrochloric acid and held in :the flame shows at once the bands Na a Ka a Li a Ca a Ca p. 4. A piece of hard potash-glass combustion tubing gavk both with and without hydrochloric acid the lines Na a and Ks a; treated with fluoride of ammonium and sulphuric acid the bands Ca a Ca @ and traces of Li a were rendered visible.5. Orthoclase from Baveno gives either alone or when treated with hydrochloi+c acid only the line Na a with traces of Li a and Ka a; with fluoride of ammonium and sulphuric acid the bright lines Na a and Ka a and a somewhat less distinct Li a are seen. After volatilization of the bodies thus detected the bead moistened with hydrochloric acid gives a scarcely distinguishable flash of the lines Ca a and Ca p. The residue on the platinum wire when moistened with cobalt solution and heated gives the blue colour so characteristic of alumina. If the well-known reaction of silicic acid be likewise observed we may conclude from this examiuation made in the course of a very few minutes that the orthoclase from Baveno contains silicic acid alumina potash with traces of soda lime and lithia; and also that no trace of barrpta or strontia is present.6. Adularia from St. Gothard coniported itself in a similar manner excepting that the calcium reaction was indistinctly seen whilst that of lithium was altogether wanting. 7. Labradorite from St. Paul gives the sodium line Na a but no calcium spectrum On moistening the fragment with hydro- chloric acid the lines Ca a and Ca /3 appear very distinct; with the fluoride of ammonium test a weak potassium reaction is obtained and also faint indications of lithium. 8. Labradorite from the Corsican diorite gave similar reactions except that no lithium was found.9. Mosanderite from Brevig and Tscheff kinite from the Ilmengebirge showed when treated alone the sodium reactioll ; 011 the aclclition of hydrochloric acid the lines Ca a and Cs p. 284 PROFESSORS KIHCHHOFF AND BUNSEN ON CMEBLPCAL 10. Melinophane from Lamoe gave the line Na a when placed alone in the flame; with hydrochloric acid the lines Ca a Ca ,@ and Li a became visible. 11. Scheelite and sphene give on treatment with hydrochloric acid a very intense calcium reaction. 12. When small quantities of strontium are present together with calcium the line Sr 6 may be most conveniently employed for the detection of this metal. In this way the presence of small quantities of strontium may be easily detected in very many sedi- mentary limestones.The lines Na a Li a IKa a especia1.lp Li a are observed as soon as the limestone is braught into the flame. Converted by hydrochloric acid into chlorides and brought in this form into the flame these minerals give the same bands; and not unfrequently the line Sr 6 is also distinctly seen. This latter appears however only for a short time and is in general best seen when the calcium spectrum begins to fade. In this way the lines Na a Li a Ka a Ca a Ca @ and Sr 6 were fobnd in the spectra of the following limestones :-Limestone from the Silurian at Kugelbad near Prague. Mus-chelkalk from Rohrbach near Heidelberg. Limestone from the Lias at Malsch in Baden. Chalk from England. The following limestones gave the lines Na a Li a Ka a,Ca a Ca /3 but not the blue strontium band Sr 8 :-Marble from the granite near Auerbach.* Devonian limestone from Gerolstein in the Eifel.Carboniferous limestone from Planitz in Saxony. Dolomite from N ordhausen in the Ham. Jura-kalk from Streitberg in Franconia. From these few experiments it is evident that a more extended series of exact spectrum analyses respecting the amount of stron- tium lithium sodium and potassium which the various limestone formations contain must prove of the greatest geological import- ance both as regards the order of their formation and their local distribution and may possibly lead to the establishment of some unexpected conclusions respecting the nature of the oceans from which these limestones were originally deposited.Barium. The barium spectrum is the most complicated of the spectra of the alkalies and alkaline earths. It is at once distinguished from all the others by the green lines Ba a and Ba ,@ (which are by far the most distinct) appearing the first and continuing during the whole of the reaction. Ba ‘y is not quite so distiiict but is still a well-marked and peculiar line. As the barium spectrum is considerably more extended than those of the other metals the reaction is not observed to so grcat a degree of delicacy; still * According to the method already described a quantity of nitrate of strontium was obtained from 20 grms. of this marble such as to give a complete and vivid strontium spectrum. We have not examined the other limestones in the same way.ANALYSIS BY SPECTRUM-OBSERVATIOXS. 0.3 grm. of chlorate of barium burnt with milk-sugar gave a distinct band of Ba a which lasted for some time when the air of the room was well mixed by moving an open umbrella about. Hence we may calculate in the same manner as mas done in the sodium experiment that about &of a milligramme of barium salt may be detected with certainty. The chloride bromide iodide and fluoride of barium as also the hydrate the sulphate and carbonate show the reaction best. It may be obtained by simply heating any of these salts in the flame. Silicates containing barium which are decomposed by hydro- chloric acid also give the reaction if a drop of hydrochloric acid be added to them before they are brought into the flame.Baryta-harmotome treated in this way gives the lines Ca a and Ca /3, together with the bands Ba a and Ba p. Compounds of barium with fixed acids giving no reaction either when alone or after addition of hydrochloric acid should be fused with carbonate of sodium as described under strontium and the carbonate of barium thus obtained examined. If barium and strontium occur in small quantities together with large amounts of calcium the carbonates obtained by fusion are dissolved in nitric acid and the dried salt extracted with alcohol. The residue contains only barium and strontium both of which can almost always be detected. When we wish to test for small traces of strontium or barium the residual nitrates are converted into chlorides by ignition with sal-ammoniac and the chloride of strontium is extracted by alcohol.Unless the quantity of one or more of the bodies to be detected is extremely small the methods of separation just described are quite unnecessary as is seen from the following experiment :-A mixture of the chlorides of potassium sodium lithium calcium strontium and barium containing at the most -&-of a milligramme of each of these salts was brought into the flame and the spectra produced were observed. At first the bright yellow sodium line Na a appeared with a background formed by a nearly continuous pale spectrum. As soon as this line began to fade the exactly defined bright red line of Lithium Li a was seen; and beyond this still farther from the sodium line the faint red potassium line Ka a was noticed whilst the two barium lines Ba a Ra 6 with their peculiar shading became distkctly visible in their characteristic places.As the potassium sodium lithium and barium salts volatilized their spectra became fainter and fainter and their peculiar bands one after the other vanished until after the lapse of a few minutes the lines Ca a,Ca p Sr a Sr p Sr 7 and Sr 8 became gradually visible and like a dissolving view at last attained their characteristic distinctness colouring and position and then after some time bccsrrie pale and disap- peared entirely. 286 PROFESSORS KIRCHHOFF AND RUNSEN ON C;iImicIiT The absence of any one or of several of these bodies is at once indicated by the non-appearance of' the corresponding bright lines.Those who become acquainted with the various spectra by repeated observation do not need to have before them an exact measurement of the individual lines in order to be able to detect the presence of the various constituents ;the colour relative position peculiar form variety of shade and brightness of the bands are quite characteristic enough to ensure exact results even in the hands of persons unaccustomed to such work. These special distinctions may be compared with the differences of outward appearance presented by the various precipitates employed for detecting substances in the wet way. Just as a precipitate is characterized as gelatinous pulverulent flocculent granular or crys-.talline so the lines of the spectrum exbibit their peculiar aspects some appearing sharply defined at their edges others blended off either at one or both sides either similarly or dissimilarly some again appearing broader others narrower ;and just as in ordinary analysis we make use of those precipitates oiily which are produced with the smallest possible qiiantity of the substance supposed to be present so in analysis with the spectrum we employ only those lines which are produced by the smallest possible quantity of substance and require a moderately high temperature In these respects both analytical metbods stand on an equal footing; but analysis with the spectrum possesses a great advantage over all other methods inasmuch as the characteristic differ- ences of colour of the lines serve as the distinguishiag feature of the system.Most of the precipitates which are valuable as reactions are colourless ;and the tint of those which are coloured varies very consi-derably according to the state of division and mechanical arrangement of the particles. The presence of even the smallest quantity of impurity is often sufEcient entirely to destroy the characteristic colour of a precipitate; so that no reliance can be placed upon nice distinctions of colmr as an ordinary chemical test. In spectrum-analysis on the contrary the coloured bands are unaffected by such alteration of phy-sical conditions or by the presence of other bodies. The positions which the lines occupy in the spectrum indicate the existence of a chemical property as unalterable as the combining weights themselves and may Lherefore be estimat,ed with almost astronomical precision.The fact however which gives to this method of spectrum-analysis a peculiar degree of importance is that it extends almost to infinity the limits within which the chemical characteristics of matter have been hitherto confined. By an application of this method to geological inquiries concerning the distribution and arrangement of the components of the various fgrmntions the most valuable results nitiy be expected ;even the few random experiments already mentioned have led to the unex- pected conclusion that not only potassium and scdium but also lithium and strontium must be added to the list of bodies occurring only indeed in small quantities but most widely spread throughout the matter composing the solid body of our planet.The method of spectrum-analysis may also play a no less important part as a means of detecting new elementary substances; for if bodies should exist in nature SO sparingly difhsed that the analytical methods ANALYSIS BY SPECTRUM-OBSERVATIONS* 287 hitherto applicable have not succeeded in detecting or separating them it is very possible that their presence may be revealed by a simple exami- nation of the spectra produced by their flames. We have had opportunity of satisfying ourselves that in reality such unknown elements exist. We believe that relying upon unmistakeable results of the spectrum-analysis we are already justified in positively stating that besides potassium sodium and lithium the group of the alkaline metals contains a fourth member which gives a spectrum as simple and characteristic as thrtt of lithium-a metal which in our apparatus gives only two lines namely a faint blue one almost coincident with the strontium line Sr 6 and a second blue one lying a little further towards the violet end of the spectrum and rivalling the lithium line in brightness and distinctness of outline.The method of spectrum-analysis not only offers as we think we have shown a mode of detecting with the greatest simplicity the presence of the smallest traces of certain elements in terrestrial matter but it also opens out the investigation of an entirely untrodden field stretching far beyond the limits of the earth or even of our solar system.For in order to examine the composition of luminous gas we require according to this method only to see it; and it is evident that the same mode of analysis must be applicable to the atmospheres of the sun and of the brighter fixed stars. A modification must however be introduced on account of the light emitted by the solid nuclei of these heavenly bodies. In a Memoir published by one of us,* ‘(On the relation between the Coefficients of Emission and Absorption of Bodies for Heat and Light,” it was proved from theoretical considerations that the spectrum of an incandescent gas becomes reversed (that is that the bright lines become changed into dark ones) when a source of light of sufficient intensity giving a continuous spectrum is placed behind the luminous gas.From this we may couclude that the solar spectrum with its dark lines is nothing else than the reverse of the spectrum which the sun’s atmosphere alone would produce. Hence in order to effect the chemical analysis of the solar atmosphere all that we require is to discover those substances which when brought into the flame produce hright lines coinciding with the dark ones of the solar spectrum. In the paper above referred to the following experimental facts are given in confirmation of the preceding theoretical conclusion. The hright red line produced in the spectrum of a gas-flame by the presence of a bead of chloride of lithium is changed into a dark one when direct sunlight is allowed to pass through the flame.When the bead of lithium is replaced by one of chloride of sodium the dark double line D (coincident with the yellow sodium line) appears with uucomrnon dis- tinctness. The dark double line _O also appears when the rays of a Drummon d’s light are passed through the flame of aqueous alcohol into which chloride of sodium is thrown.+ * ITirchhofY Poggendorff’s Annalen cix. 275; and Phil. Mag. [4] XX. 1, + In the Pliilosopliical Magazine for March 1860 Prof. Stokes calls attention to the fact that in the year 1549 Foucault made an ohswvation very similar to hhe above. In the examination of the spectrum produced by tlie electric arc between carbon points Poucaul t noticed that bright lines occur where the double line D of the solar spectrum is found and that this dark line D is produced or made more intense when the rays of the sun or those froiii one of the incandescent carbon poles are passed through the himinous are.The observation mentioned in the text affords 288 KIRCHHOFF AND BUNSEN ON SPECTRUAI-ANBEYSL5. It appeared of interest to obtain still further confirmatioil of this important theoretical conclusion ; the following experiments answered this purpose :-We ignited a thick platinum wire in the flame and then by means of an electric current heated it to 8 temperature approaching its melting- point. The wire gave a bright spectrum in which no trace of either dark or bright lines was seen. A flame of weak aqueous alcohol in which common salt was dissolved on being brought between the wire and the slit of the apparatus gave the dark line 1') most distinctly.The dark line D can be produced in the spectrum of a platinum wire heated in a flame by holding between flame and spectrum a test-tube containing some sodium amalgam which is heated to boiling. This experiment is important because it shows that sodium vapour at a temperature much below that at which it becomes luminous exerts its absorptive power at exactly the same point of the spectrum as it does at the highest temperatures which we can produce or at the temperatures existing in the solar atmosphere. We have succeeded in reversing the bright lines in the spectra of K Sr Ca Ba by employing sunlight and mixtures of the chlorates of these metals with milk-sugar.A small iron trough was fixed in front of the dit of our apparatus in which the mixture was placed; the direct sun- light was then allowed to pass along the whole length of the trough and the mixture was igaited with a heated wire. The telescope C with the wires cutting each other at an oblique angle was placed so that the point of intersection of the wires coincided with the bright line of the flame- spectrum which was to be examined. The observer concentrated his attention upon this point to judge whether at the moment of burning the mixture a dark line showed itrelf passing through the point of intersection of the cross wires. In this way it was easy when the right proportions for the mixtures were found to show that the lines Ba a Ba p as well as the line Ka p were reversed.The last of these lines coincides with one of the most distinct dark lines in the solar spectrum though not marked by Fra un h o f er which however appears inuch more plainly than it is generally Reen at the moment the potash salt burns. In order to prove that the strontium lines can be reversed the chlorate of strontium must be most carefully dried as the slightest trace of' moisture produces a positive strontium spectrum owing to small particles of salt being thrown about in the flame and thus diminishing the power of the solar rays. an explanation of this interesting phaenomenon observed by F o 11 c au 1t eleven years ago proving that it is not occasioned by the properties of the electric light which in many respects is still so enigmatical but that it arises from a compound of sodium contained in the pole and converted into incandebcent gas by the current.

ISSN:1743-6893    

DOI:10.1039/QJ8611300270

出版商:RSC    

年代:1861

数据来源: RSC