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Abstracts of the Proceedings of the Chemical Society, Vol. 4, No. 49 |
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Proceedings of the Chemical Society, London,
Volume 4,
Issue 49,
1888,
Page 27-34
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摘要:
ABSTRACTS OF THE PROCEEDINGS OF THE CHEMICAL SOCIETY. No. 49. Session 1887-88. March lst, 1888. Mr. William Crookes, F.R.S., President, in the Chair. Messrs. Lewis Walter Hawkins and B. Henry Gerrans, Junr., were formally admitted Fellows of the Society. The list of Office Rearers nominated by the Council to be balloted for on March 28th was read. Certificates were read for the first time in favour of Messrs. Joseph Cowper, St. Andrew’s Place, Penrith ; Eugene MacSwinej-, 18, Lower Kevin Street, Dublin; Henry John Palmer, 126, York Road, Bedminster, Bristol ; John Cecil Watson, The Rhyddings, OswaIdtwistle, near Accrington ; Thomas Howell Williams, 58, Lady Margaret Road, St. John’s College Park, N.W. The following Papers were read :-19. “ The origin of colour and the constitution of colouriiig matters.’’ By Henry E.Armstrong. The majority of compounds, especially those of carbon, are colour- less; and in the case of elements whose compounds are invariably coloured, the greatest diversit<y of colouring is often noticeable among the several compounds of one and the same element-as in that of chromium or manganese, for example : it is therefore clear that colour is in a high degree conditioned by special forms of intramolecular structure, and consequently that any attempt to determine the “ origin of colour ” must be based on a knowledge of the structure of coloured matters. For this reason it has become possible only within recent years to discuss the relation between colour and constitution.The author first gives an account of what, has already been done in 28 this direction, and refers to Graebe and Liebermaun’s paper on ‘L The connexion between constitution and colour in the case of organic compounds ” (Bey., 1868, 106) ; and to that, of 0. N. Witt-“ Zur Kenntniss des Baues und der Bildung farbender Kohlenstoff ver- bindungen ’’ (ibid., 1876, 522). Graebe and Liebermann laid down the rule as of universal application that, excluding coloured metallic salts of colourless organic acids, all coloured organic compounds which have been put to the test are decolorised by reducing agents (quinones, azobenzene, nitro-compounds, he.) ; and from this they inferred that colouring matters either contain elements with incom- pletely saturated affinities, or certain of the atoms are present in more intimate association than their retention in the molecule necessitates. Notwithstanding the change in our views of the con- stitution of quinone, Graebe and Liebermann’a conclusions appear still to be accepted, although if Fittig’s contention that the quinones are diketones be correct, their conclusion t,hat the colour of the quinones is conditioned by the intimate union of the oxygen-atoms obviously does not apply.Witt formulated the conclusion that the tinctorial nature of aromatic cornpounds is the consequence of the presence together of a colour-giving or chro?nophoric group, such as NO?, CO, N :N, and of a salt-forming group-either OH or NH,.This chemist directed his attention almost exclusively to the consideration of the nature of compo;nds possessed of tinctorial properties as distinct from mere coloured substances or pigments. The origin of colour, however, is presumably traceable ta similar causes in both classes of com-pounds, while the property of acting as a dye may conceivably depend on peculiarities which stand in no relation to those which are cau- sative of colour; this is an important question to determine. The dominant idea on which the argument in the paper is baaed is illustrated by the author by comparison of the unsaturated hydro- carbons with the paraffins. In the paraffins, which are singularly inert compounds and all but colourless even in the infi-a-red and ultra- violet regions of the spectrum, the carbon-atoms are united only by single affinities, and the remaining affinities are engaged by monad atoms ; iihe unsaturated hydrocarbons are not only more reactive than the paraffins, but the beginnings of colour are manifest in them if examination be made in the regions above and below the visible spectrum.The latter are conventionally represented by formuh in which the carbon-atoms appear as united by two. or three affinities of each, typified by straight lines or dots ; these formulae apparently serve to indicate that the value of a “double bond ’’ is twice, and that of a “treble bond ” thrice that of a ’‘ single bond,” and there can be little doubt that this has long been tacitly assumed, although such a doctrine may not actually have been taught.But within recent 29 years the idea has found favour that ‘‘ affinity has direction”; v. Baeyer especially has availed himself of this hypothesis in his discussion of the differences in stability of various types of closed chain hydrocarbons. The author would apply it to polyad-atoms generally ; and in formulating compounds in which such atoms are united by more than single affinities, would represent the polyad atoms as united by curved lines in order to suggest that the affinities are under strain in consequence of their being free to act only in certain direct,ions, In the paper, the author cites a large number of cases among inorganic compounds which he thinks afford evidence that the production of colour is dependent on special modes of atomic arrangement, and particularly on such modes of arrangement as involve the existence of a condition of strain in the resulting system, due probably to peculiarities in the affinity relationships of the con- stituent elements of the system which prevent complete mutual neutralisation of the affinities.The occurrence of colour therefore is more frequently than not concomitant with a high degree of reactivity, the coloured compound being usually one of “high potential” or slight stability. Among carbon compounds there is no instance of a hydrocarbon being coloured, giving the term its conventional meaning; and omitting nitro-compounds, there are very few exceptions to the rule that derivatives of hydrocarbons containing only monad radicles are colourless ; the exceptions, moreover, are of a very noteworthy character, being either centyal derivatives of anthracene, i.e., com-pounds formed by displacement of the hydrogen-atoms of the central nucleus of anthracene-which although not coloured is significantly fluorescent ; or the monad radicle contains at its origin a radicle such as CO.A number of illustrations are given in illustration of this statement. Attention is then drawn to the quinones and their deriva- tives, Fittig’s ketone formula being throughout adopted for these compounds. The author then discusses the constitution of the better known dye-stuffs, and is thereby led to conclusions which in some cases are different from those hitherto accepted. Azo-dyes.-Liebermann’s experiments on benzene-azo-betanaphthol are referred to, and also tlicse of Zincke and Bindewald, attention being specially directed to the production by these latter chemists from alphanaphthaquinone and phenylhydrazine of benzene-azo-alpha-naphthol identical with that obtained from alphanaphthol and a diazobenzene salt.The author thinks that the general bearing of these results has escaped notice, and proposes to apply them to azo- dyes generally, formulating these as of the following types :-HNG C,H,ZN*NH R’, 30 according as they are derived from phenols or amines. The high tinctorial power of the azo-dyes would appear to meet with a more satisfactory explanation on this hypothesis than is afforded by Witt's theory, and it affords 8 simple explanation of the fact that no acid radicle other than OH, and only ortho- and para-hydroxy or amido-compounds are available for the preparation of azo-dyes.The cases in which this hypot,hesis will not apply are discussed in the paper. Rosaniline and its congeners.-Although the formuh usiially assigned to these represent them as compounds of the quinonic type- assuming that in quinone the oxygen-atoms although in the para- position are united to each other, the idea that they are quinonic cornpounds which Graebe, Liebermaxin and Caro expressed prior to the publication of E. and 0. Fischer's well-known investigation has apparently now been entirely lost sight of.The author would formulate them in the manner indicated by the following examples :-OcC6H,cC (C,H,OOH), HNZC,H*ZC(CJTpNH,), Pmarosolic acid. Pararosaniline. PhthaZeiw.-v. Baeyer's researches are commonly held to prove CH2that these compounds are derivatives of phthalide, C6Ha{ co } 0. The arguments on which this conclusion is based are discussed in the paper ; it is pointed out that the properties of the various compounds classed as phthaleins are so diverse that it is desirable to more fully examine the evidence on which they are grouped together, especially as, apart from the assumption that the phthale'ins are phthalide-deri- vatives, there is little reason to believe that the lachidm are chro-mophoric compounds. v.Baeyer supposes that phenolphthalein is formed from dihydroxytriphenylhydroxymethanecarboxylic acid by separation of the elements of water from the carboxyl and the methane hydroxyl, a lactonic anhydride being thereby produced; but if the hydroxyl of the cal."boxylic radicle were to separate with a hydrogen- atom of the neighbouring C6Hd*OH,a,derivative of hydroxyphenyl-anthranol would be obtained. This latter constitution, however, has already been assigned to the phthalidein isomeric with phenot-phthalejin. The conclusion that interaction does take place in this latter manner in tJhe formation of fluoresceins would serve to explain the fact that orcinol (CH, : OH :OH = 1 : 3 : 5) does not yield a fluorescein, whereas the isomeric cresorcinol (CH, : OH : OH = 1: 2 : 4) does, as an anthracene-derivative could only be formed from an orcinol con- taining two contiguous undisplaced hydrogen-atoms. It is possible that certain of the pht halejins are derivatives of phenylenediphenyl ketone, C6Ha(COC6H5) The form ation of triphenylmet bane-deriva- 2. tives from coinpoiinds of this type can easily be accounted for, as 31 benzil is converted by alkali into diphenylglycolic acid; and this assumption would serve to explain the formation of additive com-pounds with acids, such as are obtained from orcinphthale?n, for example.It is noteworthy that the dimethanilidophthnle'in prepared from dimethylaniline is not only itself colourless, but yields colourless salts ; this may be a true phthalide-derivative. Also that the diamido- diphenylphthalide which v.Baey er prepared from diphenylphthalide and which he converted into phenolphthaleyn, when methylated yields a green compound apparently identical with the " phthalic-green " which 0. E'ischer prepared from dimethylaniline and which he repre- sented as an anthracene-derivative. Methylene-blue.--It is suggested that this also is a quinonic com-pound, thus :-N C6H3*NMe,0 s S NJle,.C,H3( )C6H,*NMe2c1 ii/N-I \/oNMe-MeC1 Bernthsen's formula. Quinonic formula. 0ther dye-stuffs arid eoloured compounds are considered in the paper. ~ISCTJSSION. Dr. DEBUSsaid that Dr. Armatrong had called attention particu- larly to the type of colonred substances.Now flowers of sulphur at -5C" are white ; larger pieces of sulphur are nearly colourless ; but on warming both forms become more and more yellow, and at +50° are of an intensely yellow colour. Whatever be the type on which sulphur molecules are built up, there is not the slightest evidence that its chemical properties are changed between -50" and +50", or in other words that the structure of its molocules is altered. The colour of sulphur, therefore, is not dependent on its chemical type between -50" and +50°, but on its temperature. Many similar examples can be quoted. Thus zinc oxide is white at common, and yellow at higher temperature. The influence of molar arrangement is seen in the following examples : larger pieces of silver are white, powder of silver is black; pieces of platinum grey, powder of platinum black ; a sublimate of mercuric sublimate is dark brown, and powder of the same substance red.In all these cases there is no evidence that the molecular structure of the substances has undergone any change. Professor R~~CKERsaid that if he had understood Professor Arm- 32 strong rightly his hypothesis mas not in any way opposed to the idea thak the forces between atomo acted in straight lines. If for purposes of illustration they made the crude supposition that a carbon-atom had four poles or centres of force on its surface, it was possible to conceive another atom adhering to one of the poles, or to a point on the surface half way between two of them.The heat of combination, the stability of the compound and so forth, would depend on the position assumed by the second atom relatively to the poles, but no single pole would have done the maximum amount of work which the attractions it exerted could perform on the atom until the latter finally adhered to it. In other positions there would therefore be a certain amount of “residual affinity.” A position of more or less stable equilibrium might be found in which an atom combining with others was under the influence of a resultant force which was not equal to the sum of its individual components, and he believed that it was ideas of this kind which Professor Armstrong’s notation was intended to convey. As regards the question whether colour was due to the internal arrangement of the molecule, absorption was ordinarily attributed to vibrations set up among the atoms of which each molecule was composed.Be thought that attempts such as that embodied in the paper to connect the physical properties of substances with the molecular con- stitutions were necessary before any further attempt was made to frame a mechanical theory by which the connection should be ex- plain e d . Professor G. C. FOSTEEH,referred to Professor Armstrong’s remark, near the beginning of his paper, that, in t$e discussion of the colora- tion of bodies, their behaviour towards the invisible ultra-red and ultra-violet parts of the spectrum could not be separated from their behaviour towards the visible rays.In his opinion this remark was of fundamental importance. It appeared to him that the real question raised by Dr. Armstrong was whether a definite relation could be traced between chemical composition or chemical structure and the existence and position of absorption-band8 in the spectrum of the transmitted radiation. The presence or absence of coloration, as it could be judged of directly by the eye, gave no conclusive answer to this question, for, as Professor Dewar had just reminded them, a sub-stance might be as colourless as water, and still exert strong absorp- tion in the ultra-red, or, as in some of the substances examined photographically by Profeesor Hartley, it might have strongly marked absorption in the ultra-violet. But, more than this, a body might exert selective absorption within the visible spectrum, but if it happened to absorb two complementary colours it would be judged of by the eye as though it were destitute of selective absorption altogether.The subject, therefore, seemed to him to involve a syste- matic study of absorption-spectra. Dr. MORLEYsaw great difficulty in applying to inorganic compounds Dr. Armstrong's hypothesis that the less stable bodies were the more highly coloured, and instanced the yellow and red mercuric iodides, the red iodide being the more stable at ordinary temperatures. Mr, A. G. GREEN remarked that, as he understood, Dr. Armstrong considered the colour of organic colouring matters to be due to the unsaturated affinities or high potential of the quinone type to which these compounds can all be referred.Now he believed Dr. Armstrong regarded water' as both an unsaturated and a coloured body, so, apply-ing the same argument, why should not all aromatic compounds capable of being referred to the water type be ooloured, or, at any rate, such as have sufficient molecular weight ? Dr. ARMSTRONG,in reply, referring to Professor Foster's remarks, said that there was great difficulty in discussing colour, owing to the want of any agreement as to a colour scale, which made it impossible to compare effects produced in different regions of the spectrum ; it would undoubtedly be necessary ultimately to take into account the absorption effected in the regions beyond the visible : at present, how- ever, there was far too little informatioil at our disposal for this pur-pose, but he believed that the same principles would apply in the main, In the course of the discussion he had been asked for explanations of matters which he did not pretend to explain; he did not claim that what he had said was particularly novel, but it did appear to him that it was of importance to group together the facts, and the conclusions with regard to t)he character of coloured compounds in.general at which he had arrived appeared to be of significance. 20. " Researches on Chromorganic Acids. Part 11. Certain Chromoxalates of the Red Series." By Emil A. Werner, The author has further studied Croft's red salt, prepared by the interaction in aqueous solution of potassic dichromate and oxalirt acid in the proportion of 1 to '7 molecules.Crofts gave to it the formula KzCr~(Cj204)~*120HZ, but the author finds only 10 OHz, Six of the 10 molecules of water are readily expelled, the red salt becoming bluish-grey ; but the remaindep are removed with difficulty, complete dehydration being effected only at about 300". The dehydrated com- pound is of a deep-green colour. It is proposed to represent the red salt by tbe formula Cr,(OIE)2 (CrOz,OH),. Several derivatives of{ (c'*Oz*OK)z the salt am described in the paper. 34 21. “Note on Benzyldithiourethane.” By A. E. Dixon, M.D. Several of the monalkyl substituted dithiourethanes are known, The following is a short account of a new member of the series.It was prepared early in 1887in Professor A. W. Hofmann’s laboratory. Benzyl mustard-oil was sealed up in a tube with a quantity of ethyl mercaptan slightly in excess of that required by the equation- CS :N*CH2*C,H,+ CZHbSH = CS(SC,H,)NH.CH,-CJ&. The mixture ww heated for five hours at a temperature of 120°, the tube opened, and the contents heated for a short time on the water- bath in order to drive off the excess of mercaptan. After standing for a few days the liquid solidified to a crystalline mass : this was dis- solved in alcohol and the alcohol allowed to spontaneously evaporate. By this means large transparent and perfectly colourless prismatic crystals were obtained, over 3 cm. in length, nearly 4cm.broad, the yield being over 80 per cent. of the theoretical. The substance is insoluble in water, moderately soluble in ether, benzene and ligroyn, and extremely soluble in alcohol and bisulphide of carbon. The alcoholic solution is instantly desulphurised on warm-ing with alkaline lead solution. The crystals melt at 47’ without decomposition ; on heating more Ftrongly the substance decomposes into mustard-oil and mercaptan. On analysis, tbe following data were obtained :-0.2545 gram burnt with PbCrOd gave 0.5329 GOz and 0.1449 H,O ; or C = 57.10 per cent., H = 6-32per cent. 0.2308 gram fused with Na2C03 + KC10, gave 0.3003 BaS04,or S = 29.80 per cent., which agrees with the formula C,,-,E,,NS2. Theory. Experiment. Cl0 ....... 119-7 56 -82 5’7 *lo -HI3...... 13.00 6 *1’7 6-32 by ,diff. -6 *65 -6 “78 -N ........ 14.01 S2........ 63 -96 30-36 --29 -80 HARRISON AND SONS, PRINTERS IN OXDINABY TO HER MAJESTY, ST.MARTIN’S LANE.
ISSN:0369-8718
DOI:10.1039/PL8880400027
出版商:RSC
年代:1888
数据来源: RSC
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