摘要:

NOTE ON PYROMUCYLHYDROXAMIC ACID, 847 XC.-Note on Pyromucylhydroxamic Acid. By ROBERT HOWSON PICKARD, D.Sc., Ph.D., and ALLEN NEVILLE, B.Sc. THE reactions of pyromucylhydroxamic acid have been studied with the view of obtaining the furfuran-carbamides and -carbarnates by Thiele and Pickard’s method (Armden, 1899, 309, 189). These are, how- ever, uncrystallisable oils, which decompose on hydrolysis (compare Freundler, Bull. Xoc. Chime, 1897, [iii], 17, 419). PyronzucyZhydroxamic acid, C,H,O*CO*NH*OH, is formed when ethyl pyromucate * is hydrolysed with an anhydrous alcoholic solution of hydroxylamine. By precipitation with a solution of copper acetate, the grass-green copper salt is obtained, which is then suspended in alcohol and decomposed by hydrogen sulphide ; on evaporation, the filtered solution yields the hydroxamic acid, which crystallises from water in lustrous, white needles and melts at 124’.* In preparing pyromucic acid by Frankland and Aston’s method (Trans., 1901, 79, 511), a better yield is obtained if the solution of the pyroniucates and lime is just rendered acid (to litmus) and then concentrated before the pyromucic acid is liberated by the addition of more sulphuric acid.848 HARTLEY, DOBBIE, AND LAUDER : 0.1351 gave 0.2329 CO, and 0.0467 H,O. 0.1686 ,, 16.8 C.C. moist nitrogen a t 14' and 727 mm. N = 11.20. C,H,O,N requires C = 47.24 ; H = 3.93 ; N = 11-02 per cent. It gives the usual cherry-red coloration with ferric chloride, is comparatively stable towards boiling hydrochloric acid, and at first the compound appeared to have an analogous constitution to the 5-phenyl- 3-isoxazolone obtained by Ruhemann and Stapleton (Trans., 1900, 77, 239) by the action of hydroxylamine on ethyl phenylpropiolate.It was, however, proved to be a hydroxnmic acid by comparing the properties of its benzoyl derivative with those of 5-p?~enyl-3-benxoyl- isoxazolone, BenxoyZ~y/ronaucyl?~y~~oxc~mic acid, C,H,O* C(0H): NO*CO* C,H,, is precipitated when a n aqueous solution of the hydroxamic acid is shaken with the calculated quantity of benzoyl chloride and sodium acetate. 0,2025 gave 10.9 C.C. moist nitrogen a t 15' and 763 mm. N = 6-32, C,,H,O,N requires N = 6.06 per cent. It has a n acid reaction and dissolves in a solution of sodium car- bonate, whilst the monobenzoyl derivative of 5-phenyl-3-isoxaxolone, which melts at 106', is insoluble in the reagent. The sodium and ammonium salts are precipitated when ether is added to their alcoholic solutions. An aqueous solution of the sodium salt, when boiled with water, evolves carbon dioxide, and a n oil (con- taining nitrogen) is obtained when the solution is evaporated. This oil is presumably the difurfurancarbamide, but decomposes completely when hydrolysed. No better success was attained on attempting to prepare the carbamates by boiling the sodium salt with alcohols. C-47.01 ; H=3.84. It crystallises from alcohol in needles and melts a t 134'. MUNICIPAL TECHNICAL SCHOOL, BLACKBURN.

ISSN:0368-1645    

DOI:10.1039/CT9017900847

出版商:RSC    

年代:1901

数据来源: RSC

摘要:

848 HARTLEY, DOBBIE, AND LAUDER : XC1.- The Absorption Spectra of Cyanogen By WALTER NOEL HARTLEY, F.R.8. ; JAMES J. DOBBIE, D.Sc., M.A., and ALEXANDER LAUDER, B.Sc. THE following investigation was undertaken with the view of ascer- taining whether, by an examination of the absorption spectra of the cyanogen compounds, it might be possibIe to throw some light upon the vexed question of the constitution of these substances. Compounds.THE ABSORPTION SPECTRA OF CYANOGEN COMPOUNDS. 849 Some of the substances of a simple constitoution belonging to this group had previously been examined. W. A. Miller and also L. Soret proved the transparency of hydrocyanic acid and the cyanides (Phil. Trans., 1862, 861 ; this Journ., 1864,2, 59 ; ArcJh. Sci. Phys. Nat. 1878,61), and Hartley independently found that hydrocyanic acid is a remarkably diactinic substance which exhibits no trace of selective ab- sorption (Trans,, 1882,41, 45). Cyanuric acid, orning to difficulties in its examination arising out of its sparing solubility and the necessity for examining warm solutions, at first appeared to give evidence of selec- tive absorption.It was subsequently proved, however, that there was no absorption band even in layers of liquid 200 mm. thick, but that the rays between wave-lengths 3330 and 2572, t o where the spectrum was sharply cut off, were only feebly transmitted (Proc., 1899, 15, 46). I n the present research, some derivatives of cyanic acid have been included, but me have directed our attention chiefly t o cyanuric acid, melamine, and their respective alkyl derivatives.The derivatives of cyanic acid which were examined are highly diactinic, and shorn only general absorption. Cyanuric acid is commonly represented as a closed chain compound in which the chain is formed of alternate atoms of carbon and nitrogen, united by alternate double and single bonds (formula I), and a similar structure is assigned t o the methyl ester (methyl cyan- urate, m. p. 135O), which is obtained from cyanuric chloride by the action of sodium methoxide. The methyl derivative (methyl isocyanurate ; methyl tricarbimide ; m. p. 175"), on the other hand, which is prepared by the distillation of potassium cyanate with potassium methyl sul- phate, is represented as a derivative of isocyanuric acid (formula 11)) which contains three ketonic groups, and has the carbon and nitrogen atoms united by single bonds only.I n this derivative, the alkyl groups are directly united to the nitrogen atoms. OH Cyanuric acid. iso-Cyanuric acid or tricarbimide. Pyridine and dimethylpyrazine, in which there are carbon and nitrogen atoms, united by alternate double and single bonds,+ exhibit strong and persistent absorption bands, the selective absorption being more marked in dimethylpyrazine (Trans., 1900, 77, 846), which con- tains two nitrogen atoms, than in pyridine, which contains only one. @ That is, which possess the true benaenoid structnre represented by alternate doiible mil single bonds, or by the cyclic formula.850 HARTLEY, DOBBIE, AND LAUDER : It was therefore to be expected that substances possessing the con stitution assigned to normal cyanuric acid and its esters would like- wise exhibit marked selective absorption, and that even to a greater degree than dimethylpyrazine.On the other hand, it was to be anticipated that the alkyl derivatives of isocyanuric acid (formula 11) would behave like piperidine and other substances composed of a closed chain of singly linked carbon and nitrogen atoms, or of a closed chain of singly linked carbon atoms, which exhibit general absorption only. All the cyanuric compounds, however, which we have examined show only general absorption, and give no indication of the presence of absorption bands. This result is what we anticipated in the case of derivatives of isocyanuric acid, but so far as cyanuric acid and its esters are concerned, it is remarkable, especially when considered in connection with the fact that no strict experimental evidence has yet been advarrced in support of the com- monly received structural formula for cyanuric acid and its derivatives. The more complete study, therefore, of this acid and its derivatives renders doubtful the correctness of the formula which was deduced in the first inatance from the examination of its optical properties.Methyl cyanurate (m. p. 135") yields cyanuric acid and methyl alcohol on hydrolysis with alkalis. It is therefore regarded as the ester of norms1 cyanuric acid (formula I), a conclusion which is supported by its method of formation from sodium methovide and cyanuric chloride. Trimethylcarbimide (m. p.175"), on the other hand, yields methylamine on treatment with alkalis, and is therefore re- garded as a derivative of isocyanuric acid (formula 11). It is gene- rally admitted, however, that chemical evidence of this kind is, in such cases, frequently misleading (Goldschmidt and Meissler, Ber., 1890, 23, 253; Michael, J. p. Chem., 1888, [ii], 37, 513 ; Hartley and Dobbie, Trans., 1899, 75,640). I n this instance, the spectrographic examination confirms the results arrived a t on purely chemical grounds. The spectra of methyl cyanurate, m. p. 135O, bear a close resemblance to those of cyanuric acid, the absorption being somewhat greater owing to the replacement of three hydrogen atoms by three methyl groups. On the other hand, the spectra of trimethylcarbimide, rn.p. 175O, notwithstanding a similar replacement of hydrogen by methyl groups, show considerably less absorption than those of cyanuric acid. In none of the cyanogen compounds is there any trace of an absorption band. Melamine and its esters show only general absorption, the amount of absorption being somewhat greater than in the case of cyanuric acid. Melamine is regarded as the triamide of normal cyanuric acid (formula I).TRE ABSORPTION SPECTRA OF CYANOGEN COMPOUNDS. 851 r;JH, RH I. p : y 11. HT'C'r;JH H,N*C *N : C *NH, HN: C C :NH Melamine or cyanurtriamide. H isoMelamine or isocyanurtriiuiide, The triethyl derivative (m. p. 74O), which is obtained by the action of ethylamine on cyanuric chloride, is, from its method of formation, considered to be a derivative of melamine; the ethyl derivative (m, p. 9 2 O ) , on the other hand, which is prepared by the desulphurisa- tion of thiourea, is regarded as a derivative of igomelamine.Here again the results of the spectrographic investigation are in accord with the conclusions arrived a t on chemical grounds. The spectra of mel- amine and the triethyl derivative, m. p. 74O, are almost identical, whilst the general absorption exhibited by the spectra of the isomeric compound is considerably less, The general result of the examination of these substances is in complete agreement with the views now generally held as to their relations to one another. As already observed, however, the absence of selective absorption is not in harmony with the constitution of cyanuric acid, as represented by a formula which is closely analogous to that of pyridine and still more closely to that of dimethylpyrazine.It may therefore be fairly considered as doubtful whether the consti- tution of cyanuric acid is rightly understood. EXPERIMENTAL. Potassium Cyanate.-Two specimens of potassium cyanate were examined ; one obtained from Schuchardt of Gorlitz, the other pre- pared by oxidising potassium ferrocyanide with manganese dioxide according to the method given by Wurtz (Ann. Chem. Phys., 1854, [iii], 42, 44). This substance is highly diactinic, 50 mm. of a solu- tion containing 1 milligram-molecule in 4 C.C. water, transmitting all rays to I/A 4128 (A 2422). Potassium cyanate has also been examined by Soret (Arch. Xci. Phys. Nut., 1893, [iii], 10, 429), who found that it gave a strong absorption band, of which we could find no indication.In the preparation of ethylcarbimide from potassium cyanate and potassium ethyl sulphate, it is essential to the success of the experi- ment that the potassium cyanate should be freshly prepared. From this it might be supposed that the potassium cyanate undergoes some change on keeping. I f this is the case, the change is not one which can be detected by means of the spectrograph, as we found the absorp-552 HARTLEY, DOBBIE, AND LAUDER : tion spectra of specimens photographed immediately after preparation and again after standing for six months to be identical. Ethyl isoCyanate ; Ethylcarbimide, b. p . 60'. Methyl isocyanate ; MethgZcarbimide, b. p . 44'. These derivatives were prepared by the interaction of potassium cyanate with potassium ethyl sulphate and potassium methyl sulphate respectively (Ann.CIbem. Phys., 1854, [iii], 42, 43; CiLern. Cenk'., 1898, i, 445). As no suitable solvent could be found for these esters, they were photographed in thin layers. Cyanuric ChZoride.-Thia substance was prepared by passing dry chlorine and anhydrous hydrocyanic acid into dry chloroform, care being taken always to keep the chlorine in excess. The chloroform was evaporated in a current of dry air and the crystalline residue of cyanuric chloride purified by repeated crystallisation from carefully dried ether ; i t melted at 146". Cyanuric Acid.---Samples of cyanuric acid obtained from various sources as well as several specimens prepared by us from urea were examined and were found to give indentical spectra. Owing to the insolu- bility of cyanuric acid, considerable difficnlty was experienced in making the spectroscopic examination.On this account, layers of greater thickness than usual of the cold saturated aqueous solution were employed, but no indication of selective absorption was observed. A layer 60 mm. in thickness of a solution containing 1 milligram- molecule in 60 C.C. uf water transmits all rays to I / X 3886 (A 2573). Methyl Cyanurate (m. p. 136").-This substance was prepared by the interaction of sodium methoxide and cyanuric chloride. As mill be seen from the curves, its spectra show close agreement with those of cyanuric acid. A layer 25 mm. in thickness of a solution contain- ing 1 milligram-molecule in 20 C.C.of alcohol transmits all rays to I / X 3922 (A 2549); Ethyl isocyanurate; Ethyltricarbimide, m. p. 95'. Methyl isoCyanurate; MethyZtrica~bimide, rn. p . 175". Two specimens of ethyl isocyaniirate were examined ; one purchased from Schuchardt, the other obtained in the preparation of ethylcarb- imide by the polymerisation of the latter substance. The photographs of the absorption spectra of the two specimens were identical. The specimen of methyl isocyanurate examined was obtained in the same way during the preparation of methylcarbimide. The photographs of the trimethyl and triethyl derivatives show almost complete agree- ment. They are more highly diactinic than the corresponding deriva- tives of normal cyanuric acid.THE ABSORPTION SPECTRA OF CYANOGEN COMPOUNDS.853 MeZamine.-The specimen examined was prepared by heating pure cyanuric chloride with excess of strong ammonia in a sealed tube at 100' for 5 hours. The melamine was extracted from the residue with water and purified by repeated recrystallisation. This substance is less diactinic than cyanuric acid, owing to the replacement of the three OH by three NH, groups. A layer 50 mm. in thickness of a solution containing 1 milligram-molecule in 40 C.C. of water transmitted all rays to '/A 3638 (A 2748). Triethyhnekcmine (m, p. 74O).-The specimen examined was prepared by heating pure cyanuric chloride with excess of an alcoholic solitlion of ethylamine in n sealed tube a t 100" for 6 hours, It was purified by crystallisation from dilute alcohol. As will be seen from the curve, its absorption is in close agreement with that of melamine.A solu- tion of 1 milligram-molecule in 20 C.C. of alcohol transmits all rays to l/A 3525 (A 2836). FriethyZisome2amine.-The preparation of this substance in a state of purity was found to be most tedious and difficult. The method followed was that described by Hofmann (Beg.., 1869, 2, 452). The yield of mustard oil was very small ; this mas also Hofmann's experience. On the other hand, no difficulty was experienced in converting the ethyl mustard oil into monoethylthiourea, although, so far as could be ascer- tained, the method which we followed did not differ from that given by Hofmann. It was found also that little heat was evolved by the action of ammonia on the ethyl mustard oil, and that the solution, on evaporation, crystallised without difficulty. The melting point of the crystals differed by only 1' from that given by Hofmann.The de- sulphurisation of the ethylthiourea mas effected by repeatedly boiling with freshly precipitated and carefully dried mercuric oxide until the oxide was no longer darkened. On filtering the solution and evaporat- ing, a thick syrup was obtained which crystallised only after long standing and upon subsequent repeated treatment with solvents, not- withstanding that every precaution was taken, as recommended by Hofmann, to thoroughly purify and dry both the mercuric oxide and the alcohol. Details are given of the preparation of this substance, as it seems to have been but little investigated since the publication of Hofmann's paper.The spectra of triethylisomelamine show less absorption than mel- amine and triethylmelamine, in this respect they bear the same relation to those substances that ethyl isocganurate bears to cyanuric acid and ethyl cyanurate. Notes on the Curves.-For an account of the method employed in drawing the curveson p. 854, see Trans., 1899, 75, 649, and the papers mentioned therein. The thickness of the layer of liquid in millimetres is given in the VOL. LXXIX. 3 N854 HARTLEY, DOBBIE, AND LAUJ>ER : Scale of oscillatiolt frequencies. FIQ. A. PIG. 13. I. Triethyl isomelamine, in. €3. 920, 11. Melsiiiine. I. Methyl isocyanurate, in. p. 175'. 11. Cyenuric acid. 111. Methyl cyanurate in. p. 136". IV. Curve deduced fdr the hypothetical iso- 111. Trietligl~iielnniine, 111.p. 74O. 1V. Curve tledueed for the hypothelieal iso- cyairuric acid. ?ueh~tine. ITHE ABSORPTION SPECTRA OF CYANOGEN COMPOUNDS. 855 column headed ‘mm.’ on the left-hand side of each of the figures A and B. I n the cqse of cyanuric acid, 1 milligram-molecule was dissolved in 60 C.C. of water, and layers of 3-60 mm. in thickness mere photographed. For the sake of easy comparison with the curves of the esters, 60 mm. of this soltition are takeh as equivalent to 20 mm. of a solution contain- ing 1 milligram-molecule in 20 c.c., and the curve plotted accordingly. The curves for the stronger solutions of melamine and triethyl- melamine are not giveh, as we were unable to obtain photographs of the corresponding solutions of triethylisomelamine for comparison.The difference betweeh the curves I1 and I11 (Fig. A) is due to the greater molecular weight of the ester, which contains three methyl groups in place of three hydrogen atoms, and therefore has greater absorption than the acid. The difference between curves I and I11 expresses the difference in the amount of absorption which is caused by the difference in constitntion of the two esters. Assuming the relation between the unknown isocyanuric acid and its alkyl derivative to be the same as that between the normal acid and its ester, the curve of isocyanuric acid would be represented approximately by the dotted line IV, The difference in the amount of absorption due to the differ- ence in constitution between the normal and the bo-acid would then be expressed by the difference between the curves 11 and 1V.The melamine curves (Fig, €3) are to be interpreted in the same manner. Potassium cganate. NIC*OIC or 0:C:NK. 1 milligram-mol. in 4 C.C. water, Thickness of layer of liquid in millimetrcs. Doscription of spec tru ni. Spectrum continuous to .................. Complete absorption beyond. Spectrum continuous to .................. Complete absorption beyond. Spectrum continuous to .................. Coinplc te absorption bey oud. Same as 4 mm., with lines showing faiiitly at ................................ it 11 11 ’/A, _I- 4125 4325 4417 4454 4561 A . 2422 2312 2263 2230 21 92 3 ~ 2856 HARTLEY, DOBBIE, AND LAUDER : Methyl isocyanate ; Methylcarbimide. CO:NH.CH,.B. p. 44O. 1/A. Thickness of layer of liquid in millimetrcs. 2 _____ - 1 A. Description of' slwctrnin. 1 Spectrum continuous to ................. I3 11 t weak from ............................. t c Complete absorption lmyoiid. Spect ruin con tinnous to .................. Complete absorption beyond. Spectrum continuous to .................. Complete absorption beyond. 3638 3462 3635 3635 2748 2585 2748 2748 Ethyl isoCyanate ; Eti$carbimide. CO:NH*C,H,. B. p. 60". Thickness of layer of liquid in millimetres. Description of spectrum, 3638 2748 Cganuric Chloride. C,N,CI,. M. p. 146'. 1 milligram-mol. in 4 C.C. alcohol. Thickness of lager of liquid in millimetres. Description of spectrum. SPf- +urn continuous to .................. Faint line a t ................................. Complete absorption beyond.Spectrum continuous to .................. Complete absorption beyond. Complete absorption beyond. Spectrum continuous to .................. Spectrum continuous to .................. ' ] A . 3315 3345 3345 3482 3516 A. 301 6 2989 2959 2871 2844THE ABSORPTION SPECTRA OF CYANOGEN COMPOUNDS. 857 -__- Spectrum continuous to .................. Complete absorption beyond. Spectrum continuous to ................. Comple tc absorption beyond. CompIete absorptiou beyond. Spectrum continuo~is to .................. Complete absorption beyond. Complete absorption beyond. Spectrum continuous to .................. Spectrum continuous to .................. Thickness of layer of liquid in millimetres. 25 20 15 3340 3438 3516 3559 3628 Thickness of layer of liquid in millimetres.60 45 30 151 YJ 6 3 Cy cmur ic ClZwid e-( con t i nued) . 1 milligram-mol. in 20 C.C. alcohol. Description of spectrum. ~ A. 2994 2908 2544 2809 2756 Cyunuric Acid. C,N,O,H,. Schuchardt’s specimen recrystallised from water. 1 milligram-mol. in 60 C.C. Description of spectrum. ____ _____I Spectruni continuous to ................. Complete absorption beyond. Complete absorption beyond. Spectrum continuous to ................. Faint prolongatioii to .................... Complete absorption beyond. Complete absorption beyond. Spectrum continuous to .................. Complete absorption beyond. Spectrum continuous to .................. Complete absorption beyond. Weak prolongation to .................. Spectrum continuous to .................Spectrum continuous to ................. 3586 4132 4132 4176 4230 4321 4368 4417 A. 25i3 2420 2420 2394 2364 2314 2289 2263855 ____-- I - - HARTLEY, DOBBlE, AND LAUDER : Methgl Cyanwate. C,N,(O-CH,),. M. p. 134.5". 1 milligram-mol. in 8 C.C. alcohol. Spectrum coritinuous to ............... Complete absorption beyond. Spectrum continuous to .................. Complete absorption beyond. Sanie as 15 mm., but faint prolonga- tion to .................................... Spectrum continuous to .................. Complete absorption beyond. Spectrum continuous to ................. Complete absorption beyond. Spectrum continuous to .................. Complete absorption beyond. Thickness of layer of liquid in niillimetres. 3922 4032 4112 4125 4176 4245 Description of spectrum.Spectrum continuous to .................. Faint line at ................................. Complete absorption beyond. Spectrum continuous to .................. Complete absorption beyond. Spectrdm continuous to ................ Complete absorption beyond. Spectrum continuous to .................. Complete absorption beyond. Spectrum continuous to .................. Complete absorption beyond, 3807 3S70 3870 391 1 4020 4112 Methyl Cyanurate- (continued). 1 milligrsm-mol. in 20 C.C. A. ~ _ _ _ 2626 2583 2583 2556 2497 2431 Thickness of layer of liquid in millimetres. Description of spectrum. A. I I I E} 15 10 2519 2480 2431 2421 a394 2355THE; ABSOIIL'TION SPECTRA O F CYANOGEN COMPOUNDS. 859 Methy2 isocyanumte ; ~~etl~~/ltricar6imide.C3OS(N*CH3)3e M. p. 175". 1 milligram-mol. in 8 C.C. alcohol. Thickness of layer of liquid in inillimetres Description of spectrum. 50 40 30 20 Spectrum continiioiis, but weak to ... Very faint indication of lines at ........ Complete absorptioii beyoncl. Spectrum continuous to.. ................ Comldete absorption beyond. spectrum contiiiuous to .................. Complete absorptioii beyond. Same as 30 mni., very faint prolonga- tioii to ...................................... And lines a t ................................. and Comlilete absorption beyond. Spectruni continuous to. .................. Complote absorption beyond. nnc1 SDec trnm con tinnous to .................. Conipleto absorptioii beyond. ~ '/A, 3313 3480 3509 3555 3625 3573 4102 4116 4306 4402 A.3018 2840 2812 2758 2873 2581 2437 2429 2322 2271 Net169 I i so Cy nnumt e ; icf e thy ltviaarbimide- (con t i n u e cl ). 1 milligram-mol. in 20 C.C. alcohol. Thickness of layer of liquid in millimetres. 25 ;:} l:} 4 3 2 1 Description of spectrum. Spectrum continuous to .................. Spectrum continuous to .................. Spectrum continuous t o . .................. Spectrum continuous to. ................. Complete absorption beyond. Completc absorption beyond. Complete absorption beyond. Complete absorption beyond. Substantially as above. Complete absorption beyond. Complete absorption beyond. Complete absorption beyond. Spectrum continuous to .................. Spectrum continuous to .................. '/A. 4321 4368 4413 4445 4560 4555 A.2314 2289 2286 2248 2192 2195860 HARTLEY, DOBBIE, AND LAUDER. Ethjl is0 Cy anum te ; Et hy I ts. icar b intide. C,O, ( N C ,H 5)R 111 illini ctrcs. TI) ickness of layer of liquid in inillimetres. 25 - -____ 20 15 30 !] 3 - .____ 1 milligram-mol. in 20 C.C. alcohol. Description of spectrum. Spectrum continuous to .................. Feeble transmission to ..................... Complete absorption beyond. Spectrum continuous to .................. Feeble transmission to.. ................... Complete absorption beyond. Spectrum continuous to .................. Lines transmitted a t ....................... and Complete absorption beyond, Spectrum contiiiuoiis to .................. Lines at ....................................... and Complete absorption beyond.Spectrum continnous to .................. Complete absorption beyond. Spectrum continuous to ................. Line at ......................................... Coniplcte absorption beyond. 4105 4335 4215 4368 4335 4347 4368 4347 4368 4325 4325 4507 4572 Melanairce ; Cyanurtriamide. C3N3(NH& 1 milligram-mol. in 40 C.C. water. If. p. 05" A 2436 2306 2372 2289 2306 2300 2289 2300 2289 2312 2312 2218 2187 4 2 Spectrum continuous to ............... Complete absorption beyond.. Cornplete absorption beyond. Coniplete absorption beyond. Complete absorption beyond. Spectrum continuous to ............... Complete absorption beyond. Complete absorption beyond. Spectrum continnous to .............. Spectrum continuous to ............... Spectrum continuous to ...............Spectrum continuous to .............. 3638 3648 3667 3707 3740 3886THE ABSORPTION SPECTRA OF CYANOGEN COMPOUNDS. 861 Thickness of layer of liquid in millimetres. 2 3 2 1 ~_ Thickness of layer of IiqiiiZ i n niillimetres. 5 4 Thickness of layer of liquid i n niillim etres. 25 20 15 10 5 4 3 2 1 Jfelcmine ; C~anui.tl.ianiicEe-(continued). 1 milligram-mol. in 100 C.C. water. Description of spoc truiii. Spectrum continuous t o . .................. Cloniple te nbsorpt ion beg on d. S1)ectruni continuous t o .................. Complete absorptioii beyond. Spcctruin continuons t o . .................. Complete absorption beyond. Spectrum contiiiuous t o .................. Coinpletc LLbsorption l~oyoiici. ' / A . 3877 3915 4035 4080 A. 2579 2552 2-176 2450 1 milligr:~~m-mol.i n 500 C.C. water. Description of spectrutn. Spectrum continuous to .................. Feeble transmission to ..................... Complete absorption beyond. Spectrum continuous t o .................. Fochle transmission t o , . .................. Complete absorption beyond. Sltcctrnni continuous to .................. Fceble transmission t o , . ................... Complete absorption beyond. 4080 4315 4125 4362 4200 4407 Description of spcctrum. Sliectruni continuous to .................. Sti ong line traiisnii ttcd a t ............... Coniplete absorption beyond. Spcctruni coiitiniious, but weak, to ... Complete absorption beyond. Spectrum continuous t o ................. Complete absorption beyond. Complete absorplion beyond. Coiiildete absorption beyond.Complete absorption beyond. Spectrum continuous to .................. Spec t r uin coniin uo 11 s t o .................. Strong line transmitted at ............... Spectrum continuous to .................. l / A . :;5% 3635 3635 3777 3812 3S30 3886 3886 A. 2450 2314 2424 2292 2360 2269 5!'riethgZn~eZanzine. C,N,(NH*CIT,), IT. p. 74". 1 milligram-mol. in 20 C.C. alcohol. A. 2536 2iG1 2751 2647 2623 2610 2573 2573862 THE ABSQRPTION SPECTRA OF CYANOGEN COMPOUNDS. Line feebly transmitted a t ............... Complt.te absorption beyond. Spcctrum continuous to .................. Complete absorption beyond. Complete absorption beyond. Spectrum continuous to ................ Complete absorption beyond. Spectrum continuous t o .................. Complete absorption beyond.Spectrum continuous to .................. Complete absorption beyond. Corn ple te absorption bey on d. Spectrum continuous to .................. Spectrum continuous t o .................. Thickness of layer of liquid in millimetrcs. :} 3 2 1 Thickness of layer of liquid in milliinetres. 5 4 3 2 1 3681 3505 3852 3911 3988 4023 4116 ~rietlL~ZmeEc~nzine-( cont i nued) , 1 milligram-mol. in 100 C.C. Description of spectrum. Spectrum continuous to .................. Strong line transmitted a t ................ Complete absorption beyonit. Spectrum continuous t o ................. Complete absorption beyonil. S pec t rum con t i nu on s to .................. Complete absorption beyond. Spectrum continuous to ................. Complete absorption beyond. 3830 3886 3856 3901 3914 Description of spectrum. Spcctrum continuous to ................. Complete absorption beyond. Spectrum continuous to ................. Complete absorption beyoiid. Spectrum continuous to .................. Complete absorptioii beyond. Spectrum continuous t o .................. Complete absorption beyond. Spectrum continuous to .................. Ccmplete absorption beyond. h. 2610 2573 2573 2563 2554 1 milligram-mol. in 500 C.C. alcohol. i/A. ._ 3914 3935 3967 3985 4043 A. 2554 2541 2520 2509 2473 ~rietl~?lZisomeZa~ie. C,N,H!( N*C,H,), + 4H,O. M. p. 99'. 1 milligram-mol. in 100 C.C. alcohol. Thickness of layer of liquid in millimetres. Description of spectrum. 20 15 10 5 4 3 2 A. 2762 2716 2628 2596 2556 2507 2485 2429FARMER : DETERMINATION OF HYDROLYTIC DISSOCIATION. S63 Ti4etl~yZisowzelamine-(continued). 1 milligram-mol. in 500 C.C. alcohol. Thickness of layer of liquid in niillimotres. Description of spectrum. Spectrum continnous to .................. Complete absorption heyond. Spectrum colitil111ous to .................. Complete absorption beyond. Spectrum continuous to .................. Faint linc a t ................................ Complete absorption beyond. Spectrum continuous to .................. Completc absorption beyond. ’I”. 4116 4165 4165 4234 4234 A. 2420 2.100 2100 2361 2361

ISSN:0368-1645    

DOI:10.1039/CT9017900848

出版商:RSC    

年代:1901

数据来源: RSC

摘要:

FARMER : DETERMINATION OF HYDROLYTIC DISSOCIATION. S63 XCI1.-A New Method f o r the Determination of Hydro- lytic Dissociation. By ROBERT CROSBIE FARMER, 13.S~. (Vict.), Pli. D. (Wurzburg), Priestley Scholar in the University of Birmingham. IT is well known that salts of weak acids or weak bases are partially dissociated in aqueous solution into free acid and base. This is due to the fact that water is to a slight extent ionised, and is therefore capable of acting at the same time as a weak acid and a weak base. I n many cases, i t becomes a matter of importance to determine to what extent this hydrolytic dissociation takes place. Walker has recently shown (Zeit. physikal. Cheni., 32, 1900, 137) that the relation between the dissociation const,ant of an acid, and tho hydrolysis of its salts may be expressed mathematically, and that if the dissociation constant for pure water is known, the hydrolysis of a salt may be calculated from the conductivity of the corresponding acid or base, and vice versd. For this reason, a more complete study of hydrolytic dissociation seems desirable. Of the methods a t present in use for the determination of hydrolysis, the chief ones are (Ley, Zed.physikal. C'hern., 1899, 30, 193), (i) The determination of the electric conductivity of the salt in question at different dilutions. (ii) The measurement of the free acid or alkali present in the system by the velocity of hydrolysis of esters, or of the inversion of sugar by a solution of the salt. Of these, the former can scarcely claim anything more than a quali- tative significance.It is known for instance, that in the case of all sodium salts which are not hydrolyyed in aqueous solution, the difference between the molecular conductivity at the diluticin v = 32864 FAlIhlElt : A NEW METHOI~ POH THE litres, and that at TI= 1024 litres approximates to 10 units. If the salt is hydrolysed, this difference will exceed 10 units, the higher conduc- tivity at the dilution 2r = 1024 litres, being due to the excass of sodium hydroxide which is set free from the salt by the water. This method is, however, neither sensitive nor exact, and so far no attempt appears to have been made to calculate the extent of the hydrolysis from the increase of the conductivity with the dilution. Tho method of determining the amount of free acid or base by the velocity of hydrolysis has, on the other hand, been used with con- siderable success.With the aid of a, somewhat complicated formula, Shields (Zed. physilcal. Chem., 1893, 12, 167) has applied the method to the measurement of hydrolysis in the case of the salts of weak acids, such as phenol, &c. Shill, there are certain cases in which Shields’ method becomes inapplicable, and it is with the view of supplying this deficiency that the following method was devised. If we attempt to apply the method described by Shields to the determination of the hydrolysis of a salt whose acid is sparingly soluble in water, me are met with the difficulty that the free acid begins to separate out from the solution before the reaction has pro- ceeded very far.The equilibrium of the system is thereby upset, and the formula for the calculation of the results ceases to hold. It also occasionally happens, in working with unstable substances, that the acid decomposes during the progress of the hydrolysis, especially if the latter requires several days for its completion up t o a point where accurate results may be deduced from it. This was found to be the case, for instance, when the attempt was made to determine the hydro- lysis of sodium nitrosophenolate (Farmer and Hantzsch, Ber,, 1899, 32, 3106). To overcome these difliculties, advantage has been taken of the fact that a substance distributes itself between two immiscible solvents in a constant ratio, independent of the dilution, that is, if we except the case of substances which exist in one of the two solvents in a state of abnormal molecular aggregation.The determinations are easy to carry out and involve much simpler calculations than the last-mentioned method. The substance used in the following experinients was one to which Shields’ method mas inapplicable, owing to its sparing solubility in water, namely, hydroxyazobenzene. If an aqueous solution of a salt of hydroxyazobenzene is shaken with benzene, some free hydroxyazo- benzene is taken up by the benzene layer. From the quantity of hydroxyazobenzene thus extracted, it is possible t o calculate to what extent the salt is hydrolysed in aqueous solution. It is first necessary to determine the coefficient of distribution for hydroxyazobenzene between benzene and water.To determine the solu- bility of hydroxyazobenzene in benzene, a certain quantity of a saturated solution was evaporated down and the residue weighed. Owing toDETERMIN A'l'ION OF TIYDROLYTIC DISSOCIATION. 865 its volatility at loo', the hydroxyazobenzene could only be slightly warmed during the evaporation (which was accelerated by a current of air), and was then dried in a desiccator until the weight mas con- stant. To determine its solubility in water, the usual method of evaporation could not be used, owing to the volatility of the hydroxy- azobenzene. The most convenient method mas to extract the hydroxy- azobenzene from the aqueous solution with ether, and evaporate down the ethereal extract. On acconnt of the great solubility of hydroxy- nzobenzene in ether, i t mas quite sufficient t o extract the aqueoiis solution twice.The residue from the ether was dried in a desiccator as before and weighed. The dried hydroxyazobenzene showed no traces of volatility on continued standing over sulphuric acid in a desiccator at the ordinary temperature. In the carrying out of the distribution experiments, me have not to do with pure benzene and water, but with mutually saturated solutions of the two solvents. The solubility determinations were therefore a190 carried out with benzene containing water and with water containing benzene, For the solubility of hydroxyazobenzene in water at 26*, the fol- lowing values were obtained : Xolubility of I~ydroxyazobenzene in pure water fyee fvom carbon dioxide. Temp. 2 5 9 (i) 1000 cx.of the solution gave 0.0227 gram hydroxyazobenzene. (ii) 1000 ,t I 1 0.0223 > ? h'olubilitp in wuter contccining benzene. (i) 3000 C.C. of the solution gave 0.0268 gram hydroxyazobenzene. (ii) 1000 ,? 9 , 0.0265 ,, 9 ) (iii) 500 9 9 >> 0.0159 ,, 9 7 Mean = 0.0284 ,, per litre. Xolubility in benzene containing water. Temp. 25'. Ten C.C. of saturated solutions gave successively 0.1525, 0.1524, Mean = 0.1520 0.1508, 0,1513, 0.1524, and 0.1528 gram of residue. gram in 10 C.C. This gives as the ratio of solubilities 0*152OxlUOO = 535. 0.0384 x 10 This was confirmed by distributing between water and benzene a quantity of hydroxyazobenzene insufficient to saturate the two solvents866 FARMER: A NEW METHOD FOR THE Distvibution of 1qd.roxyaxobsnxeiae between benzene mad water.FenZl3. 35O. Hydroxyazobeazeue from 1000 C.C. of tlic aqueous solution; 3. Ob0198 ii, 0.01 9s iii. 0;0217 iv. 0.0199 V. 0.0215 H y drox yazobeiizeiie from 10 C.C. of thc beiieciie solution. 0-1 125 0.1025 0.1 135 0-1096 0.1 152 Coefficient of Distribution. 568 518 523 55 1 536 Mean = 539 *he mean of these values, namely, 539, was taken as the true co- efficient of distribution in the following experiments. I n the determination of the hydrolysis, the barium salt of hydroxy- azobenzene was used, as it is almost impossible to prepare a caustic soda solution absolutely free from carbonate. A weighed quantity of hydroxyazobenzene mas brought into a large stoppered bottle of about 1400 c.c, capacity and a known quantity of benzene added.I n the following experiments, 60 c.ci of benzene were taken. A solution of barium hydroxide in 1000 C.C. of water was then added, and the whole brought to 25O in a thermo- stat. - Hereupon, the benzene and water mere well mixed by shak- ing, and again allowed to stand in the thermostat until the two layers had completely separated, The water was then syphoned off and 50 C.C. of the benzene removed by means of a pipette. The benzene solution was evaporated down, and the residue dried in a desiccator until of constant weight. As the solubility of benzene in water is very slight, it was not considered necessary to make allowances for the small changes in volume in calculating the concentrations of the solutions. Calculation of tlte Eesults. The coefficient of distribution for hydroxyazobenzene between benz- ene and water was found to be 639, that is, benzene always takes up 639 times as much hydroxyazobenzene as water, if th6 two solvents are present in equal volumes.We will designate this coefficient by$’. If the two solvents are present in unequal quantity, say 1 litre of water to p iitres of benzene, the hydroxyazobenzene will distribute itself between them in the ratio 1 :pF. If we take a solution of hydroxyazobenzene in baryta water and shake it with benzene, the benzene mill extract free hydroxyazobenzene from the barium salt until the two following equilibria have adjusted them selves.DETERMINATION OF HY DROLYTLC DISSOCIATION. 867 i. C,H,*N:N42,H4bOH + baOH C,H,*N:N*C,H,*Oba + H-OH. ii. Hydroxyazobenzere in water Hydroxyazobenzene in benzene.From the quantity of hydroxyazobenzene taken up by the benzene, the degree of hydrolysis can be calculated as follows. Let the concentration of the hydroxyazobenzene in the aqueous solu- tion be c2 gram equivalents per litre, and that of the barium hydr- oxide c, equivalents per litre. For each litre of water we take, as above, p litres of benzene. After equilibrium has been reached, a certain quantity of the benzene is removed by a pipette, filtered, and evapor- ated. The residue is weighed, and from its weight the quantity of hydroxyazobenzene in the whole 60 C.C. is calculated. We can calcu- late from this, by multiplying by l/qB', how much free hydroxyazo- benzene is present in the aqueous solution. This quantity must bo expressed in gram equivalents per litre.We mill call this concentra- tion c. The following quantities are therefore known : c2 = Original concentration of hydroxyazobenzene. c = Concentration of free hydroxyazobenzene in the water after shaking up with benzene. For the equilibrium : c,= 9 ) ?9 barium hydroxide. C,H,*N:N*C6H4*OH + baOH t C,H,aN:N*cG~4*Oba + H*OH, we have the equation nzld, x m2d,=na,d, x rn4d4, where m,, nag, 9n3, and waq are the concentrations, and d,, d,, d,, and d, are the degrees of dis- sociation OF the four substances. It has been shown (hrrhenius, Zeit. physikal. Chem., lS90, 5, 17) that this equation may be simplified so as to read nz1m2 = kna3m4. We have now : m, = Concentration of the free hydroxyazobenzene in the water = c. If this quantity is c, a corresponding quantity, cqF, must have been The total quantity of free hydroxyazo- Total= The remainder of the hydroxyazobenzene is present in the form of its barium salt.The concentration of the barium salt which has escaped hydrolysis is therefore c2 - c( 1 + pF). The total concentration of baryta is cl. taken up by the benzene. benzene is therefore c (in the water) +cqF (in the benzene). c( 1 + qP). m3 = c2 - c(1 + qP). Of this, part is free and part is combined as barium salt. The quantity of barium salt is wag ; the quantity of free barium hydroxide is therefore equal to c1 -xu2, that is, = c1 - C' + c( 1 + qF).868 FARMER: A NEW METHOD FOR THE m4 = Concentration of the water. This is practically constant. The equation m,mz = km,rn, must therefore be written : Consequently, km, is also constant.C(C1 - c2 + c ( l 4- pP)> = kn& - c(l + q F ) ) , or (i ) c 2 - c ( 1 + q P T ' . ' c(c* -c,+c(l CqE))} kru4 = From this equation, kr)?,4 cnn be calculated. Let us now consider the normal system, C,H,*N:N*C,H,*OIE + bnOH C,H,*N:N*C,H,*Oba + H-OH, in absence of benzene and without any excess of baryta. the condition We have mlm2 = Ena,nz,. I n this case, however, it, is evident that ml=na2 and mS=c2-m1. Consequently, 9n12 = k.im4(c2- ml). . . . . . . (ii) From this equation, ~2~ can be calculated. Finally, the degree of hydrolysis = !!!l GO and the percentage hydrolysis L 1 oom,, . . . . . . - Ca (iii) The carbon dioxide of the air must of course be excluded as rigidly as possible. It has the effect of setting free too much hydroxyazobenzene and thus giving values which' are too high.This effect shows itself most strongly when approximately equivalent quantities of hydroxyazobenzene and barium hydroxide are taken. It may, however, be almost completely avoided by using excess of barium hydroxide, so that the quantity of carbon dioxide which finds its way into the solution is small in comparison with the total amount of free alkali present. For instance, by taking dif- ferent excesses of barium hydroxide, the following values were obtained. Excess of barium hydroxide, approx. - 5 0 10 20 per cent. Percentage of hydrolysis (found) ... 1.45 1.34 1.26 1.21 ,, Concentration = N/64. Temp, = 2 5 O . Comentration = N/lOO. Temp. = 2L0. Excess of barium hydroxide, approx.0 11 20 94 per cent. Percentage of hydrolysis (found) ... 2.36 1-SO 1-55 1.65 ,, I n the case of hydroxyazobenzene i t is advisable to use an ex. cess of baryta amounting to 10 to 20 per cent. Thus, the error due to carbon dioxide is reduced to a minimum, and the quantities of2 r - i? b4 x E 1 11 iii iv i ii 111 iv ... Volume O f water iii C.C. 1000 1000 1000 1000 500 60 0.01562 0'01491 0.1695 0*00003176 loeG x 3.31 0.000226 0,0145 500 60 0'01560 0'01567 0'1287 0*0@002408 10-6 x 2.83 ' 0*000209 0.0134 x 2'51 0*000197 0-0126 1000 60 0'01564 I 0.01717 1 0.0950 0.00001780 1000 60 0.01559 0*018i2 0.0543 0 00001018 10-6 x 2'32 ~ 0*000189 0'0121 Summary of Experiments. FIRST SERIES. Dihtion- 100 litrcs. Temp. = 25". .____ i 1000 ii 1000 1 GO 0 00998 ~ C*01002 60 0.01000 0.01113 60 0.01000 ~ L"01942 GO O + O I O O O i 0.01201 __I G O 0.01250 1 0.01389 I 0.0771 0-00001445 10-@ x 2-25 60 0.01249 0'01461 1 0.0574 0*00001076 _____.- -- -- -__- Residue from 50 C.C.benzene in gram. - - 0-2027 0'0954 0.0537 0 .O! 53 - _ - ~ ~ _ - 0.0939 0.00001760 1 0 -6 x 2.34 0.000215 ' 0.0107 0.0569 0'00001066 10-6x22'44 1 0'000220 ~ 0'0110 c Calculated con. centration of the free benzene in the water. c. hydroxyazo- 1.07 1.10 0 'OOOO3795 0-00001788 0 '00001 006 0.00000287 i 1000 60 0.031 25 ii 1 500 1 60 1 0,03125 ~- 10-6x5'71 1 0 000236 10-6 x 3'29 I 0.000180 x 2'45 I 0*000155 10-6 x 2'75 1 0*000165 :':::; I "0::; 0'02974 0.3982 0*00007462 1 loe6 x 2 54 0'03438 0.0987 0'00001850 1 x 2.68 nz, c2 Equation iii. -. 0.0236 0.0180 0.0155 0.0165 Percentage hydrolysis.2-36 1.80 1 *55 1-65 -____ 1'45 1'34 1 *26 1'21 I I I I I I870 FARME% : DETERMINATION OF HYDROLYTIC! DISSOCIATION. hydroxyazobenzene in the benzene extract are still sufficiently large to be easily meigbed. The effect of dilution on the hydrolysis is expressed, as has been shown by Arrhenius, by the equation x2/(l - x)v = const., where x = degree of hydrolysis, and v = dilution. If we omit the results which were, as above shown, most affected by the action of carbon dioxide, me obtain the following Table of vesults. Dilntion. 32 32 50 50 64 64 so so 100 100 Percentago of hydrolysis. 2/(1 - z)v = const. 0-90 25 10-7 0.92 26 9 ) 1.07 23 ?> 1.10 24 ?? 1'26 25 ,, 1.21 23 ,, 1-33 22 ,, 1.32 22 ,, 1.55 25 9 ) 1 -65 2s 9 9 Mean 24.3 ,, --- According t o Walker (Zed. plqsikal. Chem., 1900, 32, 137), the dissociation constant of an acid may be calculated from the hydrolysis of its salts. If x is the degree of hydrolysis and k the dissociation constant, we have the relation, - (1.09 x 10-7)~ - X2 (1 - z)v k This would give a dissociation constant for hydroxyazobenzene of 4.9 x A discussion as t o the bearing of this on the question of the constitution of the hydroxyazo-bodies must be postponed until more accurate measurements of the electric conductivity of hydroxy- azobenzene have been made. The present paper is concerned only with the application of the method of distribution t o the determina- tion of hydrolysis. I n most cases, it would probably be advantageous to detcrmine the amounts of acid by titration instead of gravimetric- ally. This was inapplicable in the case of hydroxyazobenzene, on account of the intense colour of the solutions. The method of distribution is of course as well adapted to the investigation of the salts of weak bases as to that of the salts of weak acids. CHEMICAL LABORATOI:IES, UNIVERSITY OF BI1tBiINGHA;M.

ISSN:0368-1645    

DOI:10.1039/CT9017900863

出版商:RSC    

年代:1901

数据来源: RSC

摘要:

571 ANNTJAL GENERAL MEETING, MARCH 28~11, 1901. Professor T. E. TIIOHPE, C.E., LL.D., F.R.S., President, in the Chair, The following Report was read by the President :- THE CHEMICAL SOCIETY was founded about four years after the accession to the Throne of the Gracious Lady whose recent loss me deplore, and the memory of whose virtues and worth, as a woman and as a monarch, will for ever abide with us. We are proud to think that this Society, in so far as it has ministered to the progress of chemistry, may have contri- buted in some measure to the lustre of a reign which has been prc- eminently associated with the development and spread of science in this country, and with the extension of those arts which rest upon chemistry. We have never been unmindful of what our science owes to the Royal Family, and in particular to the late Prince Consort, whose appreciative interest in the fortunes of the Royal College of Chemistry, of which he was the President, and whose friendship for the eminent man who made it the first organised school of chemical research in this country, has directly ministered to the activity, welfare, and usefulness of our Society, We sought to give utterance t o these sentiments in an Address which we ventured to submit to His Majesty on his accession to the Throne, and in respectfully tendering our con- gratulations, and in offering our homage, we expressed the hope that his reign might be marked by discoveries in the science we represent not less brilliant than those which have characterised the reign of his illustrious mother.We enter upon the twentieth century mustering 2370 members, made up as follows : Number of ordinary Fellows on March 29th, 1900 ... 2292 ,? , I reinstated by Council ... 5 9 , 9 9 since elected ............... 117 Withdrawn ............................................... 31 Removed on account of non-payment of arrears... 26 Deceased ................................................... 20 Number of ) > - 77 ordinary Fellows on March 2Sth, 1901 ... 2337 Foreign Fellows 7, 9 , 9 9 * ' * 33 2370 3 0 2872 ANNUAL GENERAL MEETING. Since the last anniversary the following have withdrawn :-E. L. Allhusen ; J. Allport ; Frank Bastow ; F. Barker Cooke ; G. H. Cross ; Sir Michael Foster ; J. Frost ; H. E. Gardner ; J. F. H. Gilbard ; William Goddard ; Frederic Gothard ; Robert Hamilton ; Harold Ellershaw Head ; William M.Heller ; Henry Leonard Hinnell; Alfred Kingsby Howard ; Edgar Joseph ; A. E. Lewis ; C. T. Macadam ; Fred Marsden ; James Maso; John Charles Platts; Percy Morrice Randall; S. G. Rosenblum ; Edward Rosling ; James Spencer ; James H. Stebbins ; Sydney Steel ; William Ward ; A. Swainson Waterfield ; P. A. Wier. The na.mes of those removed were :-Carl Bennert ; G. F. Brindley ; R. E. Brown ; James Crowther ; W. B. Edwards ; Sidney Fawns; D. A. Griffiths; W. T. Gronow ; R. Glode Guyer ; W. G. Lasseter ; 13. E. Law; J. A. MacFarlane; Angus Mackay; E. MacSwiney; S. M. Martiu; Robert McClumpha; W. B. McVey; E. E. Milnes; H. J. Monson; R. H. Owen; J. B. Reid; H. J. Phillips; James Speakman ; Thomas Stormouth ; J.B. Thornloy ; H. W. Wallis ; A. W. Warwick; R. H. Wilson. The names of the deceased Fellows are :-Edmund Atkinson; John Borland ; Alfred Hunter Boylan ; William Harcourt Branscombe ; Sir John Conroy ; Henry Howard Crawley ; Thomas Flower Ellis ; Frank W. Harris; Herbert A. Hotblack ; Sir John Bennet Lawes ; Stevenson .Macadam ; Frederick Alfred Manning ; William McConnell ; William Parsons ; Richard Reynolds Saville Shaw ; George Smith ; C. J. H. Warden ; Augustus A. Wood; Thomas M. Wyatt. In Edmund Atkinson we have lost a fellow of marked individuality, a strong and vigorous personality, the memory of whose genial pre- sence, sturdy common sense, and mordant yet kindly humour those of us who knew him will not willingly let die. H e is best known, of course, as a physicist, as the editor of a popular text-book of physics, and as an officer of the Physical Society.But he began his scientific career as rz chemist, studying under Bunsen and Wohler, and working on glycol and on lophine. He joined our Society in 1859, wits a member of the Council in 1868-1871, in 1882-1 885, in 1891-1892, and became a Vice-president in 1893-1896. A more extended notice of his life and works will be contributed to our Journal by his life-long friends, Professor Carey Foster and Dr. Hugo Muller. By the death of Lieutenant Thomas Flower Ellis we have lost a young metallurgical chemist of considerable promise, of great per- sonal charm, beloved by all who learned t o know his frank and mady nature. He passed through the Chemical Courses of the Royal College of Science, working for a time in the research laboratory under my direction.After spending some years at theANNUAL GENERAL MEETING. 873 Straits Trading Company’s Tin Smelting Works, at Pulo Brani, as an assayer, he went to South Africa as a mining engineer, and at the outbreak of hostilities joined Thorneycroft’s Mounted Infantry, and was mortally wounded a t the disastrous reveise of Spion Kop. With what courage and hardihood he faced that terrible ordeal, and how he met his end, has been told by Mr. Oppenheim in the January number of this year’s Nineteenth Centzcry and After. Sir John Bennet Lames, a t the time of his death, had completed fifty years of membership of our body. His name is inseparably con- nected with that of his life-long friend and coadjutor, our veteran President-Sir Henry Gilbert, the father of the Society-in the de- velopment of scientific agriculture in this country, more especially in the famous field experiments at his ancestral home of Rothamsted.Sir John Lawes served on the Council in 1862-1865, and much of the outcome of the experimental inquiries which we owe to his broad- minded munificence is to be found in the pages of our Transactions. We hope to have a fuller account of Sir John Lawes’s life-work from the pen of Professor Warington. Richard Reynolds, a former Lecturer in Chemistry at the Leeds School of Medicine, now incorporated within the Yorkshire College- a constituent college of the Victoria University-who died on April 5 th, 1900, a t the age of 70, was a man who deserves t o be had in remem- brance, not only as a representative pharmacist, singularly well cul- tured and strenuously active in all that concerned the best and truest interests of his calling, but as the type of a good citizen whose highest ambition was to do what in him lay to further the social and intellectual welfare of the community with which his lot was cast.Born in Banbury, of Quaker parents, he went to Leeds in 1844 as an apprentice to the late Thomas Harvey, also a member of the Society of Friends, and a well-known citizen of that town, where his memory is still cherished as a man of rectitude, zealous and active in everything relating to the public good. The firm, which ultimately became known as Harvey and Reynolds, was origin- ally established by William West, also a Quaker, a Fellow of the Royal Society, and an original Fellow of this Society, who published a number of analyses of Yorkshire mineral springs, and who preceded Reynolds as Lecturer in the Leeds Medical School.Reynolds, also like West, became one of the secretaries of the Leeds Philosophical Society, and both were presidents of the Pharmaceutical Conference. Reynolds, in fact, was one of the founders of the Conference, and acted as Honorary Secretary until 1871. H e also took an active pnrt574 ANNUAL GENERAT; MEETING. in the work of the Yorkshire Geological Society, and served for some years on its Council. He was, too, one of the founders of the Priestley Club in Leeds, a constant attendant at its meetings, and an occasional contributor-his communications having invariably a note of interest, expressed with a fastidious neatness and precision of statement emin- ently characteristic of the man.Most of his published work appeared in the Phccrrnaceuticcd JownaI, in the Eeports of the British Associa- tion, and in the Proceedings of the Yorkshire Geological Society. H e joined our Society in 1857. Richard Reynolds will be mainly remembered for the share he took, in conjunction with the late Lord Frederick Cavendish and Dr. Heaton, of Leeds, in establishing tho Yorkshire College, now one of the most important and most successful of the provincial colleges founded upon the type of Owens College, Manchester. Richard Reynolds may be said to have dedicated his life to this work.He pursued it with a tenacity of purpose and an untiring zeal which no amount of opposition or discouragement could damp. To a quiet and somewhat reticent manner he added the saving grace of a sense of humour ; he was an excellent observer, and a good judge of men. Although not a Yorkshireman by birth, he thoroughly un- derstood, and mas quick t o recognise and appreciate, the sterling qualities of shrewdness, directness of purpose, and strong common sense which characterise the people with whom he identified himself. It was this intelligent sympathy, combined with a singular trans- parency of motive, an obvious unselfishness, and a simple, earnest manner, that, by compelling confidence, constituted the secret of his influence among the men with whom he worked. He was satisfied, however, to exercise his power in a quiet, unobtrusive way ; platform appearances and public display were utterly uncon- genial to him ; self-seeking or anything approaching to ostentation was absolutely foreign to his -nature.It is owing to the circum- stance that I knew him to be quite unmindful of his own fame, content indeed with the men8 sibi conscicb recti, that I desire now to add my meed of appreciation of the man and of the work which he achieved. I lived with him through the struggling infancy of the College, with which we both mere associated, he as Honorary Secretary to its Council, and I as its first teacher of Chemistry, I should be wanting in common gratitude if I neglected this oppor- tunity of stating how much I owe to his broad and intelligent sympathy with the objects of my chair-a sympathy springing, no doubt, in part from his old association with the work of a teacher of chemistry, but, and in no less measure, also to his inherent love of the science.His quiet trust, his courage, his resourcefulness,ANNUAL GENERAL MEETING. 87 5 never failed even at the most critical juncture in the early history of the College. Although naturally wary, cautious even to a degree, he could be bold on occasion, and seize with an unerring instinct the psychological moment which made for success, and carry with him coadjutors who had learned to trust the soundness of his judgment, and to put their confidence in his instinctive recognition of expediency and right. What the Yorkshire College has now become is largely due to the character which he and those who worked with him im- pressed upon it in the first years of its existence, and their names deserve to be writ in imperishable letter8 upon its chief corner- stone.Men with the civic virtues of Richard Reynolds are the highest ornaments of the State. We see their monuments in the number of rapidly developing places which, like Owens College and the Yorkshire College, adorn our towns and cities-colleges which have moulded, and are destined to mould still more profoundly, the intellectual features of our social and industrial life. Saville Sham, the honorary local secretary and treasurer of the Newcastle Section of the Society of Chemical Industry, died on November 5th, 1900, in the 36th year of his age, He was born a t Ardwick, Manchester, and in 1880 went to Owens College, and eventu- ally became an assistant in Sir Henry Roscoe’s laboratory.I n 1584 he was elected to a Demonstratorship in Chemistry in the Durham College of Science, Nemcastle-on-Tyne, and was made Lecturer on Metallurgy and Assaying. He did a considerable amount of extension lecturing throughout the counties of Northumberland and Durham, and in recognition of his services was given the degree of 3I.Sc. by the University of Durham. He was a member of various committees of the North of England Institution of Mining and Mechanical Engineers, for whom he carried out several experimental investigations, particu- larly on matters connected with flameless explosives, and on the micro- structure of metals and alloys, I n 1583, he communicated to us a paper on the preparation of the pentathionates, in which he established the existence of these salts, in opposition to the statement of Spring, who had impugned the accuracy of Prof.Lewes’ observations published in our Journal. He was elected into the Society in lS90. On the last anniversary, it was my melancholy duty t o have t o chronicle the loss of an unusually large proportion of our limited number of honorary foreign members. I am pleased to have t o report on this occasion that Death has stayed his hand for a while, and that the numher of our foreign Fellows remains the same as a t this time last year, namely, 33.8’76 ANNUAL GENERAL MEETING. I have the pleasure to offer, on behalf of the Society, our warm con- gratulations to our former President and Treasurer, Dr.Russell, on the attainment, this year, of his Jubilee as a Fellow of our body. Dr. Russell, we are glad t o see, wears his years so lightly that it will be news, I am sure, to most of the Fellows to learn that he wxs elected into the Society so far back as the epoch of the Great Exhibition, within ten years, in fact, of its foundation. He has lately, as we know, renewed his youth, and we may confidently hope that he will continue to cultivate, with unabated nrdour, those congenial inquiries which the calls of office, and of professional duty, left him but little leisure to pursue. Mr. Nevi1 Story Maskelyne, late Professor of Mineralogy in the University of Oxford, sometime Keeper of the Minerals in the British Museum, and a former Vice-president of this Society, also attains his Jubilee its a FelIow this year. I- beg to offer him our congratulations on this event, and to express the hope that he may speedily recover from the illness with which he has recently been attacked.Sir David Gamble, C.B., a well-known leader of chemical industry in South Lmcashire, and Mr. Edward Riley, the veteran analyst, who served on the Council in 1878-1879, and was a frequent contributor to our Journal, more particularly on subjects connected with the metal- lurgy of iron, are also to be congratulated on reaching, this year, the fiftieth anniversary of their election into the Society. Foreign Secretary had the pleasure of tendering, by direction of the Council, our felicitations t o our eminent Foreign Member, Professor Wladimir Markownikoff, of the University of Moscow, on the occasion of the conimemoration of the 40th year of his Doctorate.Courtesies like these add to the comity of nations and serve to show that whatever political or racial divisions may separate people, men of science are linked together in a common brotherhood, Since the last Anniversary, 182 communications have been made to the Society, as against 175 on the last occasion. This number is greater than we have had in any preceding year. I n character and variety, the last year’s communications will, I think, compare favour- ably with those of any previous session. Abstracts of all have appeared in the Proceedings, and 106 have already been published in the Transactions.The volume of Transactions for 1900 contains 127 memoirs, occupying 1210 pages ; in the preceding year 120 papers were published, occupying 1166 pages. Of the 127 memoirs, 19 were concerned with General and Physical Chemistry, 17 with Inorganic Chemistry, 84 with Organic Chemistry, 6 with Analytical Chemistry, and 1 with Mineralogical Chemistry. Papers on Physiological Chemistry or on the Chemistry of Vegetable Physiology and Agricul- I n the early part of this year, ourANNIJAL GENERAL MEETING. 877 ture are comparatively seldom brought before our Society, and not a single communication on these departments of science appears in the Journal of last year. I ventured on the last occasion to impress upon contributors the wisdom of condensation ; if brevity is the soul of wit, diff iiseness is no less the bane of science, The profit with which one reads a contri- bution is not always in direct proportion t o its length.It is a remnrk- able fact that memoirs which have been, ns it were, points of departure in t’he history of our science, such, for example, as Cavendish’s famoils paper on the synthesis of water, Davy’s papers on the discovery of potassium and on the nature of chlorine, Williamson on etherificntion, have occnpiecl only a few pages of printed matter. The list of famoils memoirs of which the same may be said might be greatly extended. You have only to glance at the publications of the Alembic Clnb, or at O+it\vald’s reprints of Chemical Classics, to see horn tersely all tliat we esteem best in our litcrature has been expressed.The character of our published work is, of course, the true index of our usefulness, and we have a just pride in the regard which is every- where paid to our Journal. But to those who are entrusted with the management of the affairs of the Society the steadily increasing ninss of literature t o be dealt with is a subject of no little concern. The cost of publication is increasing even more rapidly than the increase of matter to be published, and each year sees a n addition to the expenses on account of the Journal and Proceedings i n the Treasurer’s Balance Sheet, with no proportionate increase in the income of the Society. We trust, therefore, that contributors may bear these facts in mind, and extend their sympathy towards that most hardly worked of all our Committees-the Publication Committee.J t s methods may a t times appear draconian, but, after all, we must, t o use the homely phrase, cut our coat according to our cloth. Those coats are not neces- sarily the best cut which contain a superfluity of cloth. The volumes for 1900 contain 3758 abstracts of papers, published mainly in continental journals, occupying 1492 pages. Although the number of abstracts dealt with is 141 more than in the preceding year, which in its turn was nearly SO0 more than in 1898, the space occupied is less by 300 pages than last year. I venture to think that the character of the abstracts as faithful risuinSs of contemporary chemical literature has in no wise suffered from the condensation t o which they have been subjected.The abstracts may be classified as follows :-878 ANNTJAL GENERAL MEETING. PART I. i%ge~. NO. of Abstracts. Organic Chemistry ................................. 712 1355 PART IT. General and Physical Chemistry ............... Inorgahic Chemistry .............................. Mineralogical Chemistry ........................ Chemistry of Vegetable Physiology and A gri- culture ............................................ Analytical Chemistry. ............................. Physiological Chemistry ........................ 467 383 174 336 368 675 780 2403 - -- Total in Parts I, and I T ................... 1492 - 3758 I am sure, too, the Fellows must have noted with satisfaction the unvarying regularity with which the Journal now makes its appear- ance with the beginning of the month.I am also able to congratulate the Society on the more prompt appearance of the Annual Index. For some years past the annual volumes have been indexed by a special staff under the direction of the Sub-Editor, but after the work of compiling the Collective Index, extending from 1873 to 1892, was finished, the Index Committee suggested to the Council the propriety of entrusting the duty of pre- paring the Annual Index to one person, who should be responsible, under the direction of the Editor, for its speedy publication. Mrs. Dougal, who compiled the Collective Index, has, at the request of the Council, taken charge of this work, and the new Index has, I trust, now reached the Fellows. Although this degree of promptitude compares very favourably with that obtained under the former system, we have reason to hope, from the experience of the last twelve months, that it may be possible, by a fresh arrangement with our printers, to issue the Annual Index within six or eight weeks after the completion of the year to which it relates.I n addition to the 127 memoirs, the volume for 1900 contains no fewer than four Memorial Lectures on the life-work of distinguished Foreign Members, namely, Victor Meyer, Bunsen, Friedel, and Nilson. I n the January number of the present volume appears the admirable account of Rammelsberg’s life and labours, which we owe to Professor Miers. The Society has now accumulated n considerable number-inANNUAL GENERAL MEETING. s79 all 13-of these monographs of the work of eminent Fellows of this Society-men who have been largely instrumental in moulding the chemistry of the last half-century.Among them are masters of deter- minative chemistry, Stas, Bunsen, Marignac, Nilson, and Rammelsberg ; leaders in organic chemistry, Hofmann, Ke kuld, Victor Iteyer, and Friedel ; Pasteur, the greatest of biological chemists ; distinguished workers in the borderland connecting physics and chemistry, Kopp and Helmholtz ; and Lothar Meyer, historian and systematist. Now that the end of the century has been reached, the Council has deter- mined to put together these memoirs, and to issue them, as indeed was intended from the outset, in a separate volume. The whole work will constitute a most interesting record of the personal history of chemical science during the last half-century.It forms, too, a worthy monu- ment to those whom me seek to commemorate, and a token of our gratitude for the services which they have rendered to humanity. Tho inention of the name of Helmholtz recalls t o our minds the graceful and eloquent tribute which was paid t o the genius and labours of that eminent man in this room by one whose voice is now for ever hushed. Fitzgerald was not of our number, but with that frank and ready courtesy so characteristic of his generous nature, he promptly responded to our invitation to act as the exponent of our homage to the memory of the great philosopher who, in that never-to-be-forgotten lecture of 1S81, had himself testified before this Society, and in one of the most remarkable gatherings of which I have personal knowledge, to the feeling with which the whole civilised world regards the name of Michael Faraday.No man was more fitted to discharge the duty me had imposed upon him than Fitzgerald; himself a man of singular originality, he possessed a fine critical insight and a power of just appraisement which, joined to a scrupulous love OF truth and a con- tempt for the mere commonplaces of eulogy, made his estimate of tho power and true place in science of Helmholtz one of the most weighty and most convincing contributions yet made to the series of our Memorial Lectures. During the last Session of Parliament, the attention of the Council was directed to the possible influence of the Copyright Bill, then before a Committee of the House of Lords, upon the Society’s activity as a publishing agency.The Bill, as originally drafted, appeared t o affect our interests very considerably. Indeed, the position of journals like our own, which are largely concerned with scientific matter derived from foreign journals, to which our own Journal is equally accessible, had apparently not been considered by the promoters of the measure. Representations made to Lord Monkswell’s com- mittee, as the result of the consideration which was given to the subject by our Publication Committee, and by committees of societies880 ANNUAL GENERAT, MEETING. similarly affected, led to modifications in the Bill which largely, if not entirely, removed our objections. The measure, however, was not proceeded with in the Commons, and of course lapsed with the disso- lution of Parliament.But it is to be reintroduced, I understand, during the present Session, and in its new form may need t o be recon- sidered by the Society. As regards the Library, i t appears thnt S10 books have been issued to Fellows during the last year, as against 790 during the previous year. The additions during the last year have been 102 books, 327 volumes of periodicals, and 30 pamphlets, as against 114 books, 39’7 volumes of periodicals, and 24 pamphlets in the previous year. Fifty- nine of the books have been presented by authors, publishers, and others. A nar~ber of books and periodicals not bearing in any may on the work of the Society have been removed from the Library. Some pro- portion of these have been offered to, and accepted, by the British Museum, and the remainder will be disposed of either by presentation to kindred societies or by sale.The books belonging to the Society are now distributed through various rooms in the building, not only in the Library proper, but also in the Tea Room, in the Council Room and in the Secretary’s office. It is a matter of some anxiety to the Library Committee to make pro- vision for the inevitable and necessary growth in the number OC our books: and at the present rate of increase in our collec- tion-and it is difficult to see how this can be greatly diminished-the time is not far distant when the whole of the available shelf-room mill be occupied, From a careful measurement made for me by the Assistant Librarian, it appears that we at present possess 1786 feet of shelving, of which 1623 feet wore occupied a t the end of 1900.Some portion of this shelving already bears two rows of books, but it appears that little, if any, space can be gained by ‘‘ backing,” or by rearranging the position of the shelves in the cases. We have there- fore not more than about 165 linear feet of shelf-space left in all the rooms together, and this, at our present rate of accumulation of books, will be wholly occupied within the next 2; years, The matter will no doubt soon require to be considered by the Library Committee. 1 am informed that the only other available storage place for books is the room adjoining the Meeting Room, hitherto known as the Prepara- tion Room, and which to fit up as a library will need very consider- able structural rearrangement.On thelast occasion I made reference to the fact that the condition of the Library Catalogue had received the attention of the Library Committee, and that on their reccommendation the Council had decided that a now Catalogue should be prepared upon a planANNUAL GENERAL MEETING. 881 suggested by the Committee. It is now within sight of completion. The Author catalogue is finished, and consists of 4713 book entries and 1586 entries of pamphlets. The subject index is sufficiently advanced t o allow of an estimate being made of its size ; it mill pro- bably contain 5500 entries. The volume when printed will amount to about 360 pages. An estimate for printing is now in course of prepar- ation. The question of altering the day and hour of the Ordinary Meetings has recently been brought under the consideration of the Fellows.The expediency of making a change has been suggested on more than one occasion, and in fact the past records of the Society show that the Council have made alterations from time t o time in the day of meeting on good cause shown, although, as might be anticipated, such changes have been invariably resisted by a minority. The Ordinary Meetiags were originally on Tuesdays; the day was subsequently altered to Monday, and was changed to Thursday on the removal of the Society t o its present quarters. As the present day and hour have been so long in vogue: the Council resolved, rightly, in my opinion, to deprecate any change unless it could be shown to meet with the distinct approval of the greater number of the Fellows. It was urged by those who advocated the alteration that a great change had come over the social life of London during the sixty years of the Society’s existence. A greater number of what used t o be called the ‘resident’ Fellows now live in the suburbs which are extending in all directions, and are further and further removed from London proper.Moreover, it must not be lost sight of that the facilities for reaching town during recent years have so greatly increased that it seemed worth while to inquire whether a rearrangement of the day and hour of the meeting might not render it possible for the country Fellows t o attend in greater numbers than hitherto. No better way of testing the question seemed to present itself than that of placing a definite suggestion before the general body of the Fellows, and of inviting them t o express an opinion. A Committee, consisting of the officers and nominees of the Council and of the Fellows appointed to examine the replies which were received, reported that of the 1900 cards issued to Fellows, exactly 1000 were returned as replies.Of these 581 were un- reservedly in favour of the cliange, namely, 256 London Fellows arid 325 Country Fellows. 1 IS Fellows, whilst not voting unreservedly for the change, said they offered no objection to it. 172 Fellows were un- reservedly opposed to the change. Of the 138 Fellows remaining, S8 expressed no objection to the change of day, but offered suggestions as to change of hour, 3 suggested meeting a t 3, 1 at 4, 1 a t 4.30, 12 at 5, 12 a t 6, 9 a t 6.30, 10 a t 7, 5 a t 7.30, 15 at 8, and 2 a t 8.30.11 suggested a later hour than 5.30 without particularising it, and 4S82 ANNUAL GENERAL MEETING. alternately 5.30 and 8. 21 Fellows suggested meeting on some other day than Wednesday or Thursday, namely, 2 on Monday at 5.30, 1 on Tuesdayat 8, 14 on Friday, 10 of whom preferred 5.30. Of the remain- ing 4, 2 indicated no preference as to hour, 1 suggested 8, and 1 sug- gested S.30. 7 Fellows suggested various hours on Saturday afternoon or evening. 16 Fellows preferred Thursday, but suggested some other hour than 8, 11 suggested 5.30, 1 preferred 6, and 3 preferred 7. 1 sug- gested 8.30. 4 Fellows deprecated the change on the ground that it clashed with the present arrangements of the Society of Public Analysts.Analysing the voting cards of those Fellows who have contributed papers to the Society, 266 of whom have responded, 188 have voted for the change and 78 against it. I n view of this expresson of opinion, the Council came to the con- clusion that it is desirable that the suggested change should be provision- ally tried during the coming session, The Ordinary Meetings of next session will therefore be held on the 1st and 3rd Wednesdays of the month at 5.30. It is suggested that the Fellows should have the opportunity of meeting for tea about half an hour before the timo at which the chair will be taken. Experience can alone decide whether the alteration suits the general convenience of the Society, For some time past our sister society in Berlin has had under con- sideration the desirability of establishing, with the co-operation of the various Chemical Societies in Europe and America, a uniform system of atomic weights.Professor Landolt, as chairman of the German Committee which initiated the suggestion, addressed an invitation to this Society to participate in the movement, and the Council appointed a small Committee to consider the question. On their report, it has been decided that we should take part in the formation of the Inter- national Committee suggested by the German Chemical Society, and that the delegates of this Society to the International Committee should be Professor Thorpe, Professor Tilden, Professor Dunstan, Dr.Scott, Professor Meldola, Sir William Crookes, Professor Dewar, and Dr. Russell. With a view of arriving, if possible, at a basis of agreement, or at least of narrowing the area of disagreement, the Committee, as desired, considered certain questions put before them by the German Chemical Society and it was decided to recommend (1) That O= 16 be taken as the basis of calculation of atomic weights. (2) That in assigning a number as the atomic weight of any element only so many figures should be employed that the last may be regarded as accurately known to one unit in that figure. We have also concurred in the suggestion of the German CommitteeANNUAL GENE It AL &I E ETI N C: . 883 that it would be desirable t o form a small sub-committee of the inter- national body of delegates to settle details when agreement has been reached upon points of principle, and we have nominated Dr.Scott as the British member of this Committee. These decisions have been communicated to the German Committee, and steps are being taken to form the International sub-committee with a view to the compilation of the uniform table of atomic weights suggested. In vacating the office to which, by your kindness, I was elected two years ago, it only remains for me to thank you for the consideration and forbearance which have been uniformly extended to me, not only during the term of my presidency, but also throughout the whole period of my official connection with the Society. This connection which, as a member of Council, as a Vice-president, as Treasurer, and, lastly, as President, has covered some 17 years, constitutes one of the happiest memories of my life.Those with whom I have worked ~ R V B , I know, recognised with a generous appreciation that whatever may have been my shortcomings I have tried, to the best of my poor ability, to faith- fully discharge the trust and obligation imposed upon me. And of this I am convinced, that whatever measure of success I may have had- whatever measure of approval I may have gained-is t o be ascribed to the constant kindness and sympathetic co-operation of those with whom it has been my good fortune t o be associated. Dr. ARMSTRONG proposed a vote of thanks to the President, coupled with the request that he would allow his address to be printed in the Fransnctions.Prof, SNITHELLS seconded the motion, which was carried by acclama- tion. The PRESIDENT having returned thanks, Prof. TILDEN, F.R.S., the Treasurer, in giving an account of the Balance Sheet which he laid before the Society, duly audited, said :- The receipts had been :-By admission fees and subscriptions, g4290 ; by sale of Journal and advertisements, 2,880 12s. 9d. ; and by dividends on invested capital, &464 14s. 4d. The total receipts from all sources amounted to 25668 19s. 8d. The expenses had been : -On account of the Journal, $3512 9s. l l d . ; on account of the Proceedings, 2,250 15s. ; on account of the preparation of a new Catalogue, $51 16s. 4d. ; on account of the Library, 3238 15s. 114 ; House expenses, 2,210 9s. lld. ; the total expenditure being 2,4832 3s.9d. The TREASURER, in concluding, proposed a vote of thanks to the auditors, which was acknowledged by Ah. PAGE.884 ANNUAL GENERAL MEE'L'ING. Prof. EMERSON ~~EYNOLDS, F.R.S., proposed a vote of thanks t o the Prof. COLLIE, F.R.S., seconded the motion, which was unanimously The Scrutators having presented their report to the President, he Officers and Council. adopted. Prof. DUNSTAN, F.R.S., responded. declared that the following had been duly elected :- President : J. Emerson Reynolds, D.Sc., M.D., F.R.S. Vice-presidents who Imvejijilled t?Le ofice of I'yesident : Sir F. A. Abel, Bart., G.C.V.O., IC.C,B., D.C.L.,F.R.S.; 1I.E. Armstrong,Ph.D.,LL.D., F.R.S. ; A. Crum Brown, D.Sc., LL.L)., P.R.S. ; Sir W. Crookes, F.R.S. ; James Dewar, M.A., LL.D., P.R.S.; Sir J. H. Gilbert, Ph.l)., LL.D., F.R.S. ; J. H. Gladstone, Ph.D., D.Sc., F.K.S. ; A. Vernon Harcourt, M.A., D.C.L., F.R.S.; H. Rliiller, Ph.D., LL.D., F.R.S.; W. Odling, M.B., F.R.S. ; W. H. Perkin, LL.D., Ph.D., F.1i.S. ; Sir 13. E. Koscoe, D.C.L., LL.D., F.1t.S.; W. J. Russell, Ph.D., F.R.S.; T. E. Thorpe, C.B., Ph.D,, D.Sc., LL.D., F0r.Sec.R.X. ; A. W. Williamson, LL.D., F.R.S. Vice-Presidents : E. Divers, M.D., D.Sc., F.R.S. ; C. E. Groves, F.R.S. ; Prof. Herbert McLeod, P.R.S. ; Prof. H. A. Miers, M.A., F.1t.S. ; T. Purdie, Ph.D., F.R.S. ; T. Stevenson, M.D. Secretaries: Wyndham R. Dunstan, MA., F.R.S. ; A. Scott, M.A., D.Sc., P.R.S. libreign Xec.r.etwry : R:~phacl Meldols, F.W.S. l'recwwer : William A. Tilden, DSc., P.1I.S. Ohher Jfenabers of Cowcil : H.I-Sreretori Baker, A1.A ; 5'. I). Chntta- may, Ph.D., D.Sc. ; Frank Clowes, D,Sc. ; A. W. C~.ossloy, Ph.D., D.Sc. ; A. E:. Dixon, M.D. ; Prof. J. 3 . Dobbie, M.A., D.Sc. ; I€. J. H. Fenton, M.A., F.B.S. ; M. 0, Forster, Ph.l)., D.Sc. ; D. Howard ; 8, U. Pickering, M.A., F&S. ; W. J. Pope ; James Walker, D.So.THE TREASURER OF THE CHEMICAL SOCIETY IN ACCOUNT WITH THE RESEARCH FUND. DR. FROM MARCH 2 4 ~ q 1900, TO MARCH 2 3 ~ ~ , 1901. CR. 2 g 1900. E E ?4 ’ Mar. 24. 1901. Mar. 23. .€ 5. d. 2 s. d. Balance a t Bank, March 24, 1900 147 10 8 Year’s Dividends on &4,400 Metropolitan Board of Works 34 per cent. Stock ............... Year’s Dividends on €1,000 North British Railway 4 per cent. No. 1 Preferencestock 38 9 0 Year’s Dividends on $1,034 Great Western Railway 24 per cent.Debenture Stock ......... 24 13 4 146 18 10 210 1 2 Repayment of Uuexpended Grants 11 2 5 Repayment of Income Tax ...... 4 1 0 Assets. Estiinnted VaIz6c. Balance a t Bank ..................... 192 15 3 €4,400 Metropolitan Board of 61,000 North British Railway 4 per cent, No. 1 Preference Stock .............................. 1245 0 0 321,034 Great Western Itailway 24 per cent, Debenture Stock 894 8 2 &7128 3 5 Works 34percent. Stock ...... 4796 0 0 -- -- 2372 15 3 1900. s. d. $2 s. d. June 20. Grants to J. McCrae .................. 5 0 0 ,, F. C. Garrett ............... 10 0 0 ,) E. J. Russell ............... 15 0 0 ,) A. Lapworth ............... 15 0 0 ,, A. Lapworth ............... 10 0 0 ,, G. D. Lander ...............10 0 0 ,, G. Young ..................... 10 0 0 ,) J. Wade ..................... 10 0 0 ,, H. 0. Jones .................. 10 0 0 55 0 0 Dec. 20. ,, J. J. Sudborough ......... 15 0 0 ,, W. J. Pope .................. 50 0 0 105 0 0 Longstaff Honorarium (Prof. Perkin, F. R. S. ) 20 0 0 Mar. 23. Balance a t Bank ........................ 192 15 3 1901. -- 2372 15 3 Audited with vouchers and found correct. FREDERIC JAS. 31. PAGE. 1 E. W. VOELCKER. 23rd March, 1901. f ALFRED C. CHAPMAX.586 ANNUAL GENERAL MEETING . ANNUAL GENERAL MEETING . THE TILtEASURER IN ACCOUNT WITH THE CHEMICAL SOCIETY. FROM MARCH 241.~. 1900. TO MARCH 2 3 ~ ~ . 1901 . DR . Balance a t Bank. March 24th. 1900 ................................................................. ., in hands of Treasurer ........................................................................ Transferred from Deposit Account .................................................................. Receipts by Life Compositions.Admission Fees and Subscriptions froin 3 a t 812. 1 a t 810 ........................................................................ 116 Admission Fees ............................................................................. 1 Suhscription for 1692 a t 8 2 ............................................................... 1893 ., 8 2 ............................................................... 3' Sub&riptio& for 1894 ,, 8 2 ............................................................... 1 Subscription for 1896 a t 8 2 ............................................................... 2 Subscriptions for 1S97 ..$22 .............................................................. 13 ,, ,, 1898 ,, 32 ............................................................... 99 . . . . 1899,, 82 ............................................................... 4 ., , . 1900 ,. %1 ............................................................... 6 I I 1, ............................................................... 970 ., 1) , . 9. 32 ............................................................... Sale of Journals ............................................................................................ ,, Proceedings ....................................................................................... General Index : To the Public.............................................................. To Fellows .................................................................. :: Old&ock '1 ........................................................................................ Proceeds of Advertisements in Journal ........................................................... Subscription from the Society of Chemical Industry t o June. 1900 ..................... March 24th. 1900, to March 23rd. 1901 :- Life Compositions-4 a t %SO, 2 Bal . at 828. I a t 120, 2 a t $215. 1 Bal . a t 310, 677 8 , I 9 i401 ;; 2; .............................................................. . , .. ............... 9 . ,, Public Analysts to January 1st. 1901 I I ,, Physical Society to January 1st. 1901 ..............................Repayment of Income Tax ............................................................................. Year's Dividends on g6. 730 Metropolitan Board of Works 34 per cent . Stock ...... 8 , .. &l, 050 London and North-Western Railway Debenture Stock 9. ,, 81. 520 148 3d Cardiff CorporationStock &I. 400 India 24 per cent . Stock ........................................ I 1 ,, g2.358 Midland 23 per cent . Preference ............................. .€2. 400 Bristol 24 per cent . Debenture ............................... Int&est on &nk Deposit ............................................................................. . . ........................... ? Y ,, \ \ March 23rd 1001 . Balance at bank (Current Account) ........................(on Deposit) ................................. " in'kands of l'reasurer ................................. $6. ($0 Metropolitan Board of Works 33 per cent . Stock d1. 050 London and North-Western Railway Debenture Stock ............................................................. dl 520 148 . 3d . Cardiff Corporation 3 per cent . Stock ... E2:358 Midland Railway 2& per cent . Preference ...... 61, 400 India 24 per cent . Stock ............................... - 8 2 . 400 Bristol Corporation 24 per cent.Debenture Stock € 1313 750 7335 YO97 1475 1921 2052 1211 8 . d . 12 7 0 0 1 3 14 0 5 0 1 7 15 4 0 0 0 0 - 817. 156 9 9 - € 8 . a . 826 15 3 0 2 8 .- 282 0 0 464 0 0 2 0 0 2 0 0 6 0 0 2 0 0 4 0 0 26 0 0 19s 0 0 4 0 0 1354 0 0 6 0 0 1940 0 0 666 9 6 12 16 @ 14 4 0 4 0 0 ..16 10 0 147 13 3 8 8 0 12 12 0 1 2 1 2 0 13 5 7 224 15 3 30 1 1 43 G 10 33 7 11 56 4 11 57 0 0 6 1 3 4 .. 887 d 8 . d . CR I Expenses on Account of the Jozcrnnl and Proceedimp . € a . d . 1 8 . d . 526 17 11 500 0 0 Salary of Editor ............................................................................................. 250 0 0 ,, Sub-Editor ...................................................................................... 200 0 0 ,, Indexer ......................................................................................... 8 0 0 0 Editorial Postages .......................................................................................... 14 6 10 Abstractors' Fees .......................................................................................... N O 3 0 Printing of Journal ........................................................................................ 1941 0 10 Printing of Advertisements ........................................................................... 23 13 2 Printing Wrappers ....................................................................................... 07 10 0 Distribution of Journal by Printers .................................................................. 357 11 B J , ,, Society 1 3 7 1 Authors' Copies ................................................................................................ 85 14 0 Illustrations for Journal ................................................................................. 103 3 6 Printing of Proceedinw .................................................................................... 378 13 8 Distribution of Procegdings ............................................................................ 7 2 1 4 Publishers' Commission ................................................................................... 71 6 11 4290 Advertising Agents' Commission .................................................................... 22 2 10 .................................................................. 3512 9 11 -- 250 15 0 - 9 3 9 9 Expenses on Account oy the Library Cutulog.zJe.Salaries ...................................................................................................... 5 0 0 0 880 12 0 Pettyexpenses ............................................................................................... 1 1 6 4 51 16 4 -- Expenses on Account of the Library .33 12 0 Salary of Library Assistant ............................................................................ 5 2 0 0 Books and Periodicals .................................................................................... 11 9 0 g Binding ......................................................................................................... 67 15 2 Salary of Assistant Secretary ............................................................................ Pension to Mr . Hall Miscellaneous Printing ................................................................................... 464 14 11 Stationery ................................................................................................... Address to the King ...................................................................................... Indexing for International Catalogue .............................................................. List of Fellows and Bye Laws ........................................................................... ....................................................................................... \ ...S6995 17 7 House Expenses . Providing Refreshments .................................................................................. 20 3 10 45 11 7 Heating the Building (Coals) ........................................................................... 2 1 8 9 Cleaning ....................................................................................................... 1 5 0 0 Repairs ........................................................................................................... 1 6 7 5 Petty House Expenses ................................................................................... 17 10 1 House Porter's Wages .................................................................................... 6 5 0 0 ,, ,, Uniform ................................................................................ 7 0 0 Annual Fee t o Gate Porter ............................................................................. 2 2 0 Inhabited House Duty .................................................................................. 0 6 3 Lighting the Building .................. (Gas. 220 Is . Id . ; Electric Light. S.25 10s . 6d.) 236 200 15 0 11 0 130 0 0 87 19 3 1 2 13 0 9 0 0 7 1 0 0 6 3 1 6 Bank Charges. Treasurer's Stamps and Drafts ................................................... Treasurer's Petty Cash Disbursements ............................................................ Assistant ....................................................................................... Pos&e Account : Office and Secretarial Postages 87 58 . 7d . ; Postal Cards ~ and Stamped Envelopes (Clay). €20 11s . 3d . : Embossed StamDs . 812 12s .... Transferred to Deposit Account ........................ 1 . . Balance a t Bank .......................................................................................... ,, in hands of Treasurer ........................................................................ ............................................ 210 13 0 10 40 750 1313 0 9 11 1211 1 5 0 0 8 10 0 0 1 2 7 1 3 86995 17 7 ___~__ Audited with vouchers and found correct . ~ R ~ D ~ ~ , $ ~ ~ & M PAGE* ) ALFRED C . CHAPMAN . 2Srd March. 1901 . 3 ~ 2

ISSN:0368-1645    

DOI:10.1039/CT9017900871

出版商:RSC    

年代:1901

数据来源: RSC

摘要:

888 OBITUARY. OBITUARY NOTICES. EDMUND ATKINSON was born in 1831, a t Lancaster, where his father carried on business as a pharmaceutical chemist, H e mas educated at the Lancaster Grammar School. After leaving school he entered his father’s business, and a t the same time became a student of the old Mechanics’ Institute, in the working of which he took great interest, and in July, 1849, when only eighteen years of age, was elected a member of the committee of management. Shortly after this, he entered Owens College, then recently founded, where the late Sir Edward Frankland, the fir stProfessor of Chemistry, was among his tutors. After going through a course of study, he proceeded to Germany, spending three years at the Universities of Marburg, Heidel- berg, and Gottingen, where he graduated as Ph.D., and then continued his studies under Adolphe Wurtz, in Paris.While working with Wurtz, he succeeded in considerably simplifying the preparation of acetate of glycol, a substance a t that time of great interest, and ‘‘ Atkinson’s process ” soon came into general use. After returning to England, he spent some time at Queenwood College, Hampshire, where he wa.s associated in the teaching staB with Tyndall, Hirst, and Debus. He then became assistant to the late Sir Benjamin Brodie, first in London and afterwards at Oxford. Subsequently he was appointed lecturer on chemistry and physics at Cheltenham College, and ranks as one of the earliest systematic teachers of these subjects in a large public school. From Cheltenham College, he passed on to the Royal Military College, Sandhurst, and afterwards to the Staff College, as Professor of Experimental Science.I n 188’7 he retired from his Professorship, but continued to live near the Staff College, and for many years took an important and useful part in local affairs. One of the services that he rendered to his neighbours was that of obtaining the official recognition of the change of the name of the locality from Cambridgetown to the more euphonious Camberley. He was elected a fellow of the Chemical Society in 1859, and was repeatedly a member of the Council. It was he who suggested that the Society’s memorial to Faraday should take the form of a lecture- ship, to bear his name and to be held from time to time by a foreign man of science selected for the office by the Council.He mas one of the founders of the Physical Society, and wan, with a short interval, treaaurer of the Society from its foundation until a short time before his death. Dr. Atkinson’s services to science by the translation of numerous French and German works, among which we may specially mentionOBITUARY, 889 Ganot’s (‘ Physics,” Helmholtz’s ‘( Popular Lectures,” Dubois’s (( Mag- netic Circuit,” and Mascart and Joubert’s ‘‘ Electricity and Magnetism,” are well-known. For many years, too, he contributed to the Philosophical Magazine periodical reports on chemical papers published in France and Germany. Of late years, however, these have been superseded by the much fuller and more systematic Abstracts published by the Chemical Society.He had an intimate knowledge of German, such as is not common among Englishmen, even when they are chemists, and was remarkably well read in English, French, and German literature. His clear-sighted, but genial, common sense caused his counsel to be much sought after by his many friends, and his kindly humour made his advice as pleasant to receive as it was profitable to follow. Dr. Atkinson was married in 1869 to Mary Lang, daughter of Christopher Thomas, Esq., of Bristol. He died in May, 1900, after a very short illness, leaving four sons and two daughters. SIR JOHN CONROY, Bart., was born in 1845. He was thegrandson of the first baronet, who was Equerry to the Duchess of Kent. He was educated at Eton and Christ Church, taking, in 1868, R first class in the Final Honour Schools of Natural Science.Leaving Oxford in that year, he devoted much of his time to original research. He published his first paper in our Journal in 1873. H e returned in l%SO to Oxford as Science Tutor at Keble College. I n 1887 he became Science Tutor a t Balliol, being elected to a fellowship three years later, He was elected to the Royal Society in 1891. His original work comprises papers on the borderland of Physics and Chemistry. He published in all sixteen papers, u On the dioxides of calcium and strontium ” (this Journal, 1873), ‘‘ On the polarisation of light by crystals of iodine ” (Proc. Roy. Soc., 1876), “On the absorption spectrum of iodine” (PYOC. Rop. Xoc., 1876), ‘‘ On light reflected from potassium perman- ganate crystals ” (Phil.Mag., 1878), ‘‘ On the distribution of heat in the visible spectrum ” (Phil. Mag., l879), four papers on metallic reflection (Proc. Boy. Xoc., 18’79, 1881, 1883, 1884), ‘‘ Spectrum of the light emitted by a glow worm” (ATature, 1882), “A new photo- ineter”(Phil. Mag., 1883), “The amount of luminous and non-luminous radiation emitted by a gas flame” (Proc. Roy. Xoc., lSS9), “The amount of light reflected and transmitted by certain kinds of glass ” (Phil. Trans., 1889), ‘‘ The change in the absorption spectrum of cobalt glass produced by heat ” (Phil. gag., 1891), “ The refractive index of water at temperatures between 0’ and 10’” (Proc. Roy. Xoc., 1895). His unfailing tact and real kindness He was an ideal college tutor,890 OBITUARY. endeared him to all who knew him, Both his College and the University at large will feel his loss for many years to come.He died on December 15, 1900. By his will he left much valuable apparatus and a large sum of money for the benefit of $he laboratory of the College which he had served so well. H. B. B. BY the death of SIR JOHN BENNET LAWES, BART., we have lost one who, for two generations, filled a conspicuous place in the world of chemistry and agriculture. He was born at the Manor House of Rothamsted, Herts, on December 28, 1814. His father, Mr. John Bennet Lawes, died when his son was eight years of age. The boy was sent to Eton, and afterwards to Brasenose College, Oxford, where he did not take a degree. H e has described his youthful pursuits as ‘‘ of a most desultory character ” ; they included the performance of chemical experiments at home, to the natural disgust of his elders.A t the age of twenty he entered on the personal management of the family estate, which included a farm of 250 acres. One of his first acts was to fit up one of the rooms in the house as a laboratory. His chief chemical friend and instructor at this time was Dr. Anthony ToddThomson, Professor of Materia Medica at University College. The inspiration thus afforded naturally led to pharmaceutical work, Medicinal plants mere grown at Rothamsted, with the object of isolating their active principles. Dr. Thomson’s process for making calomel and corrosive sublimate, by the combustion of mercury in chlorine gas, was started on a manufacturing scale in one of the barns belonging to the farm, but after some serious accidents was given up.The earliest experi- ments relating to agriculture began in 1837, plants being grown in pots with various manures. The pot experiments were continued in 1838 and 1839, and led to the discovery of the manurial value of superphosphates. The first phosphate treated with sulphuric acid was the waste animal charcoal of sugar works ; apatite and other phos- phates were soon treated in a similar way. In 1840 and 1841, the experience gained in pots was confirmed by trials on a larger scale in the field. I n 1842, a patent was taken out for the manufacture of superphosphate. The life work of Sir John Lawen divides itself at this point into two distinct branches. The manufacture and sale of superphosphate led him into a most successful career as a chemical manufacturer.The field experiments led, on the other hand, to the establishment and gradual development of the wonderful series of agricultural investiga- tions now connected with the name of Rothamsted. We mill glance first at his work as a chemical manufacturer.OBITUARY. s91 The first chemical manure factory was established on Deptford Creek in 1843. The work soon outgrew the size of these premises, and, in 1857, 100 acres of land were purchased at Barking Creek, and a second and much larger factory erected. The whole of the manure business was sold in 18'72 for &300,000. Superphosphate was at first prepared from bones, bone-ash, waste animal charcoal, and apatite ; the use of Suffolk (crag) coprolites and of Cambridge (green sand) coprolites followed.The vast deposits of mineral phosphates in other countries have since taken the place of English coprolites, and superphosphate is now chiefly prepared from South Carolinan, Floridan, Algerian, and Belgian phosphates. The total imports of phosphates to Great Eritain in 1899 amounted to about 500,000 tons ; this would probably yield about 900,000 tons of super- phosphate. The manufacture abroad is on an equally large scale. The beneficial results which have followed the introduction of superphos- phate as an agricultural manure are incalculable. The manufacture of artificial manures was by no means the only enterprise in commercial chemistry conducted by Sir John Lawes. I n 1866 he became, unwillingly, the owner of the tartaric and citric acid factory a t Millwall, and at once proceeded to develop the work with his accustomed energy.HQ sent Mr. Grosjean to Sicily in 1868, and started the manufacture of citrate of calcium a t Palermo, the citrate being sent to England in place of boiled lemon juice. He introduced the manufacture of tartaric acid from wine lees, in place of the crystallised tartar previously employed, and had agents abroad to purchase lees from the wine-makers. By these, and a variety of other economies and improvements, he was able, not only t o with- stand the powerful competition of Germany, but to increase the business tilt he became by far the largest producer of tartaric and citric acid in this country. Sir John Lawes was always ready to allow the publication of work done in his laboratories, and a number of papers by Warington and Grosjean, describing results obtained in the laboratory at Millwall, will be found in the Transactions of this Society, and in the Joumccl of the Society of ChrnicalIndustry.Sir John Lawes had several other commercial ventures, including a large sugar estate in Queensland; but we need speak here only of work having a chemical interest. We turn now to the agricultural investigations conducted at Roth amsted. While the commercial work was extending so rapidly in London, the agricultural researches were developing as quickly at home. In 1843 Sir John Lawes engaged Dr. (now Sir) J. H. Gilbert, who had previously acted as assistant to Dr. A. T. Thomson, to assist in the management of these researches.The association of Lames and892 OBITUARY. Gilbert as agricultural investigators continued for fifty-seven years, and was only terminated by the death of Sir John Lawes. Previously to the commencement of the Rothamsted investigations, the only systematic study of the problems of practical agriculture was that made by Boussingault, on his own farm at Bechelbronn : his re- searches were of great value, but were not permanently continued. The work a t Rothamsted has been carried on continuously to the present day, and thus the Rothamsted station is now the oldest of the existing agricultural stations. The earliest German station, that at Mockern, dates from 1852 ; and the first American station, that at Middletown, from 1875. There are now several hundred stations in Europe and America.It is to the work done a t these stations that we owe the gradual creation of agricultural science. The development of the work st Rothamsted must now be noticed. I n 1843 were commenced the systematic field experiments on turnips and wheat. The wheat field has grown wheat without intermission ever since. In 1847 the field experiments on beans commenced, and in 1848 those on clover, and on a four-course rotation. I n 1851 the rotations of wheat and fallow, and wheat and beans were started, I n 1853 the field experiments on barley commenced. In 1856 those on grass land, I n 1869 those on oats. I n 1870 those on sugar beet. I n 1876 those on potatoes and mange1 wurzel. I n all, about forty acres were brought under experiment.The plan in every case was to grow the same crop year after year on the same land, both without manure, with farmyard manure, and with manures supplying nitrogen (as ammonium salts or nitrates), phosphates, and salts of potassium, sodium and magnesium in known quantities. The same kind of manure was applied every year to the same plot. The produce of each plot was carefully weighed, and at the laboratory the propor- tion of dry matter and ash was determined, while in selected instances the percentage of nitrogen was ascertained, and the plant ash was submitted to analysis. Later in the experiments the soil and subsoil of the plots have been subjected to chemical examination, and in the case of the wheat field the drainage waters from all the plots have also been analysed.Such, in few words, has been the scheme of the Rothamsted field experiments; the object in view has been to study the character of each crop, and to obtain statistics as to the influence of cropping and manuring upon the composition and fertility of the soil. Nowhere else have field experiments been attempted on such a comprehensive scale. Experiments on sheep-feeding with various foods commenced in 1848. I n 1848-1850, ten animals-oxen, sheep, and pigs--of various ages and condition as to fatness, were analysed ; the water, fat, nitro-OBITUARY. 893 genous matter and ash in the several parts of the body being deter- mined. Subsequently the composition of the ash was ascertained. With the exception of the analyses of the bodies of pigs since made in America, these analyses still remain the only ones which have been attempted on farm animals. I n 1850 an extensive series of pig-feeding experiments were made, which greatly helped to prove the production of fat from carbohydrates, and showed the fallacy of reckoning the nutritive value of Poods from the proportion of nitro- genous constituents which they contained.The old barn continued to be the only chemical laboratory at Rothamsted up to 1855. I n 1854 a subscription was opened for a testimonial to Sir John Lawes, for his great services to agriculture ; the testimonial at his request took the form of a laboratory, which mas opened at a public gathering on July 19, 1855.” Large out- buildings have since been added for the storage of samples.l n the new laboratory, the classical research on the assimilation of nitrogen by plants was carried out; the whole of the experimental work of this research was conducted by Dr, E. Pugh. Here, too, the numerous exact analyses of plant ash by Richter were made; and here in later years the researches on nitrification by Warington were conducted. The laboratory has also been largely used for the botanical analyses of the hay grown by various manures in the permanent grass experi- ments. I n recent years, the determinations of nitrogen and nitric acid in the soils and subsoils of the experimental fields have occupied a large share of the laboratory work. Investigations have also been conducted by outside workers on Rothamsted material, as the analyses of drainage waters by Voelcker and Frankland, and the recent laborious researches of Dyer on the amount and solubility of the phosphoric acid and potash in manured and unmanured soils of known history.Among the important investigations conducted by Sir John Lawes we must not omit to mention his work on the Royal Commission appointed in 1857, ‘‘ To inquire into the best mode of distributing the sewage of towns, and applying it to beneficial and profitable uses.’’ Two members of this Commission, Lawes and Way, conducted for several years important experiments on sewage irrigation at Rugby : the investigation dealt with the quantity and composition of the grass manured with sewage, and its value as food for fattening oxen and milking cows, including the composition of the milk obtained.The effluent waters from the irrigated fields were also analysed, and the formation of nitrates in large quantities was demonstrated. * Sir John Lawes’ characteristic speech on this occasion has fortanately been preserved, Bee Herts Guardian, July 28, 1855, or Gardeners’ Chronicle and Agri- cultural Gazette, July 15, 1871, p. 918.894 OBITUARY. Again, in 1863, the aid of Rothamsted was sought by the Govern- ment, the object in this case being to ascertain whether the malting of barley resulted in any increase of its value as a food. A con- siderable bulk of barley was divided into two lots, one of which was malted, and the loss in dry matter ascertained ; feeding experiments were then made, in which the nutritive effect of a given weight of barley was compared with that shown by the quantity of malt which could have been produced from it.The trials with oxen, sheep, and pigs were made at Rothamsted, and those with milking cow8 at Rugby. The full report was presented to Parliament in 1866. It is impossible to enumerate here the various reports on agricultural subjects which have issued from Rothamsted ; these have appeared in very various publications, the majority of them in the Journal of the Royal Age*icultural Xociety. Some of those communicated to the Chemical Society will be presently noticed. The collected Rot hamsted reports now occupy ten volumes ; copies of these have been presented by Sir John Lawes to numerous Institutions in this country and abroad. We should also mention the annual Memoranda,” giving an account of the manuring and produce of the experimental fields, and intended primarily as a guide to visitors.In middle life, Sir John h w e s was a frequent contributor of short practical papers to agricul- tural newspapers, both English and American. He also occasionally lectured to Parmers’ Clubs and Agricultural Societies. s i r John Lawes early formed the resolution of providing for the continuance of the work at Rothamsted after his own death. H e made public mention of this intention at the opening of the new laboratory in 1855. When disposing of the manure business in 1872, he announced that he had set aside ,$100,000 as a permanent endow- ment of the Rothamsted Experiment Station. In 1889 the sum named was placed in the hands of trustees, and the future manage- ment of the institution was vested in a committee of nine members, nominated by the Royal Society, the Linnean Society, the Chemical Society, and the Royal Agricultural Elociety.As an example of private munificence for the f urt,herance of scientific investigation, the establishment, the maintenance, and the endowment of the Rothamsted Agricultural Experiment Station stands in this country without a parallel. One provision of the trust deed should perhaps be noticed; it ciirects that a person shall be sent occasionally to the United States to lecture on the results of the Rothamsted experiments. Four courses of these lectures have been already given by R. Warington, J. H. Gilbert, H. E. Armstrong, and B. Dyer. The jubilee of the Rothamsted experiments was celebrated on July 29th, 1893, the arrangements being made by the Royal AgriculturalOBITUARY.895 Society. A meeting was held in front of the laboratory, the Minister for Agriculture (the Right Hon. Herbert Gardner) in the chair. Numerous addresses were presented to Sir John Lawes and to Dr. J. H. Gilbert by various public bodies, including one from the Chemical Society. Sir John Lawes also received his portrait painted by Herkomer, while Dr. Gilbert was presented with a piece of plate. A granite boulder with an inscription commemorating the fifty years of experimental work already accomplished was erected in front of the laboratory. Dr. Gilbert afterwards received the honour of knighthood from the Queen. The honours bestowed on Sir John Lames in recognition of his labours as an investigator were very numerous.He was elected a Fellow of the Royal Society in 1854, and in 1867 one of the Royal Medals was awarded to him and Dr. Gilbert. I n 1882 Mr, Lawes was created a baronet. The degree of doctor was conferred on him by the Universities of Edinburgh, Oxford, and Cambridge. I n 1894 the Albert Gold Medal of the Society of Arts was presented to Sir John Lawes and Sir Henry Gilbert “for their joint services to scientific agriculture, and notably for the researches which, through- out a period of fifty gears, have been carried on by them at the Experimental Farm, Rothamsted.” Foreign distinctions were equally numerous. He received a gold medal from the Imperial Agricultural Society of Russia, In 1881 the German Emperor awarded to Lawes and Gilbert a gold medal for agricultural merit.I n 1893 Lawes and Gilbert received the Liebig Silver Xedal from the Bavarian Academy of Sciences. Sir John Lawes was elected a corresponding member of the Institute of France in 1879, and was a Chevalier du Merite Agricole, and a member of many Societies. A few words must be said as to the relations between Sir John Lawes and the Chemical Society. He was elected a Fellow in 1850 and in 1862 became a member of the Council. His colleague, Dr. Gilbert, was a still earlier Fellow, and became a member of the Council in 1856. The work carried out at Rothamsted was chiefly concerned with the chemical aspects of agriculture, and mas thus of the greatest interest t o chemists. Feeling this, Sir John Lawes was in the habit of frequently inviting the members of the Council to Rothamsted during the month of June.I n early days, when no rail- way had found its way to Harpenden, the chemists stayed at Roth- amsted for the night, and after a day spent in studying the experi- ments in progress, devoted the evening to equally welcome relaxations, and, according to a well preserved tradition, sometimes played at leap- frog round the lawn I It was remarked at the commencement of this notice that the work a t Rothamsted has already extended through the lives of two generations; this fact is brought vividly before one when896 OBITUARY. memory recalls the scenes of these early visits. The present writer can look back to chemical parties a t Rothamsted, including Graham, Brodie, W.A. Miller, Mathiessen, Williamson, Hofmann, De la Rue, and Warington, senior. The communications of Rothamsted work to the Chemical Society include four lectures by Dr. Gilbert-“ The chemical statistics of the animal body,” May 21, 1855 ; “The composition of the animal portion of our food, and on its relations to bread,” Feb. 17, 1859; “The assimilation of nitrogen by plants,” March 5, 1863 ; ‘(The composition, value, and utilisation of town sewage,” Feb. 1, 1866. Also a paper on the composition of wheat grain and its products in 1857; and a more complete investigation on the composition of the ash of wheat grain and wheat straw in 1884. The composition of soils was dealt with in a paper in 1885. There are also eighteen papers in the Transactions on work done in the Rothamsted laboratory by various investigators.I n conclusion, we must try to say a few words as to the man himself, the founder and inspirer of the work we have now described. It is almost needless to say that Sir John Lawes was a man of great physical vigour and untiring energy. When past 85 he still exhibited few of the infirmities of old age. He was a keen observer, and knew the experimental fields better than any of the Rothamsted workers. Not the fields only, but the birds and every living thing on the estate. The large amount of business he was able t o get through was in no small degree due to his calm and cheerful temperament, which no disaster seemed to disturb. This quiet, self-contained temperament sometimes appeared as reserve or even shyness, and led to a reluctance t o accept public positions or to take part in public functions ; but his work doubtless gained by this refusal to expend his energy on outside occupations. The reserve we have mentioned was, however, a mood rather than a character, and disappeared the instant he was appealed to by any scientific or benevolent question.To speak to him of agri- cultural science would a t once open the storehouse of thought and lead to a discourse of ready eloquence, interspersed with shrewd observa- tions and humorous remarks. Sir John Lawes was an enthusiastic investigator of agricultural problems, with the consideration of which his mind seemed to be con- tinually occupied, His view of all questions was broad and states- manlike, and he was cautious of adopting untried theories or recom- mending a new practice to farmers.Having farmed his own land all his life, he knew what was practicable for a farmer, and what were the necessary conditions of profitable work. With regard to his own achievements, no one could be more modest. He seemed without personal ambition, He rejoiced that the agricultural investigationsOBITUARY. 89’7 prospered, and looked forward to their growing in importance, but he was ever ready to ascribe their success to the workers whom he had gathered round him. Whatever may be the future of the Rothamsted experiments, the original mind cannot but be greatly missed. Teeming with suggestions and fresh views, carefully criticising results, grasping at once the practical bearing of each new fact, Sir John Lawes was throughout his life the inspirer and the best exponent of the Rothamsted experiments.We speak in these pages of Sir John Lawes as a scientific man, but the record of his life would be very incomplete without some reference to his efforts to benefit the agricultural labourers of his parish and the workmen of his factories, and his readiness to help in every good work. Allotment gardens, co-operative stores, schools, mission rooms, and a savings bank were all started and continuously supported by him. Finding that the poor people of Harpenden did not like that others should know the extent of their savings, he used to come down himself on Saturday evening to receive their deposits. This savings bank was started by him in 1856, and continued till the opening of the Post Office banks. Sir John Lawes died at Rothamsted after a short illness on August 31, 1900. R.W. One instance of his personal service shall suffice. STEVENSON MACADAM was the second son of William Macadam, Burgess of Glasgow and delaine manufacturer in Kilmamock, and was born in Glasgow in 1829. He received his first chemical instruction from his brother John at the Mechanics Institution in Glasgow, and afterwards proceeded to the University of Giessen, where he graduated as Doctor of Philosophy. On John leaving for Melbourne to take up the position of Professor of Chemistry in the newly started University there, Steven- son came to Edinburgh t o occupy the position vacated by his brother of assistant to Dr.George Wilson. This post he held until Wilson became Professor of Technology in the University, when Macadam was appointed Extra-Mural Lecturer on Chemistry in the School of Medicine, Surgeons’ Hall, which post he held until the time of his death. Shortly after coming to Edinburgh, Stevenson Macadam was elected a Fellow of the Royal Society of Edinburgh and ever after took an active part in its work, contributing many papers as well as taking part in the general work of the Society. I n 1856, he joined the Royal Scottish Society of Arts, to which he contributed in all some 44 papers and addresses, and was twice elected President. In the formation of the Society of Chemical Industry he took a part and was one of the founders. Several papers were communicated by him to this Society and appear in the journal.He was also one of the founders of the Institute of Chemistry.898 OBITUARY. His published papers cover a wide range. I n his earlier days he gave much attention to the physical side of chemistry, and his papers on such subjects are numerous and at the time received much attention, One of the first physical papers had as its subject the physico-chemical properties of gases, in which he referred especially to the specific gravity, solubility, diffusion, and transpiration, as well as diaIysis and absorption, of this state of matter. This paper was printed in 1851. I n the same year, a paper appeared in the New Philosophical Journccl on C‘A new theory of the central heat of the earth and the cause of volcanic phenomena,”as well as one on the “ Cause of the phenomena exhibited by the geysers of Iceland.” I n 1852 and 1858, papers appeared in the same journal on the “ General distribution of iodine,” in which i t was proved that that element did not occur in the atmosphere, in rain water, and in snow, as had been maintained by M. Chatin in a paper read before the Academy of Sciences, Paris. Water supply also took up much of Dr. Macadam’s attention and led to the publication of many papers, not only on the subject of drinking waters and the sources of pollution, but also on the contamination of such by public works, &c. The Tradeston flour mill explosion in 1872 led to an inquiry in which Dr. Macadam took an active part, and during the investigation of the cause it was shown, not only that flour might be highly explosive, but that this property was shared by coal dust, sawdust, and other finely divided substances. I n 1870, the Northern Lighthonse Board employed Dr. Macadam to investigate the illuminating properties of paraffin oil as well as the safety of such illuminant in lighthouses. This investigation proceeded until 1878, when, as the result of the work, all the Scotch lighthouses were illuminated by means of paraffinoil. The valuation of fuels, both solid and liquid, received much attention and many investigations, and reports were published by him on this subject. He conducted a large consulting practice, but yet found time for sport, and was a keen angler and otter hunter as well as a splendid walker and oarsman. He died in January, leaving a widow, two sons (both Fellows of this Society), and two daughters.

ISSN:0368-1645    

DOI:10.1039/CT9017900888

出版商:RSC    

年代:1901

数据来源: RSC

摘要:

THE CHLORINE DERIVATIVES OF PYRIDINE. PART VII. 899 XCII1.-The Chlorine Deyivatives of Pyrzdine. Part VII. Some Condensution Products. By W. J. SELL, M.A., F.R.S., and F. W. DOOTSON, M.A., D.Sc. IN Part I11 of this series of papers (Trans., 1899, 75, 979) a number of compounds were described as resulting from the action of dry chlorine on pyridine hydrochloride. Among these was a substance to which the empirical formula C1,HN2G'1,, mas assigned, but no struc- tural formula was offered. The present communication deals with some of the reactions of this compound, and the bearing which the results have on the constitution which should be assigned to it. (1) I n the communication referred to above, it was stated that the substance interacts with water, forming hydrogen chloride, and a new compound, also insoluble in water, having the molecular formula C,,HON,CI,.In order, if possible, to gain a clearer insight into the relationship between the two compounds, a quantitative examination of the interaction was made. In the result, there remained no doubt that the roaction takes place according to the equation : C,,HN,Cl,, + H20 = C,,HON,Cl9 + 2HCl. With water at a higher temperature (120-130°), the substance darkens in colour, evidently decomposing, and in the liquid there is found 2-amino-3 : 4 : 5-trichloropyridine (Trans., 1900, 77, 771), held in solution by the hydrogen chloride also formed, When the substance C,oHN2Cl,I is crystallised from ethyl alcohol, a similar interaction takes place, and the compound C,,HON,CI, is deposited.The ready interaction with water and with ethyl alcohol, with the formation of an oxy-derivative, accompanied by hydrogen chloride in one case and alkyl chloride in the other, suggested the possibility that organic acids, for example, acetic or benzoic acid, might interact with formation of the acid chloride. This was found to be the case, a theoretical yield of benzoyl chloride being produced from benzoic acid. I n the case of acetic acid, acetyl chloride was recognised as one of the products formed. The crystalline residual product of these interactions was identical in properties and composition with that left by treatment of the parent substance C,,HN,Cl,, with water. Hence the change may be thus represented : CloHN,CI1, + C6H6*CO2H = C,oHON,C19 + c613[,*cocl + HGl,900 SELL AND DOOTSON: This behaviour is remarkable, and, so far as we are aware, is the first recorded instance in which the acid chloride has been formed by the interaction of an acid with a purely organic substance.It may here be pointed out that, in the cases cited, the oxygen is in the OH condition. Ketonic oxygen does not appear t o react under these conditions, inasmuch as the compound may be recrystallised unchanged from acetone. (2) When the substance C,,HON,CI, is treated with a, solution of sodium hydroxide and the resulting magma distilled in steam, a bulky crop of filamentous needles separates out from the distillate. This was found to be 2-amino-3 : 4 : 5-trichloropyridine (compare Part 111, Trans., 1899, 75, 981 ; also Trans., 1900, 7’7, 771).(3) Interesting results were obtained by treating the substance with sulphuric acid contaiuing approximately 80 per cent. of the acid. The experiments were made under varying conditions of time and tempera- ture. When the compound was merely dissolved in the acid at a temperature not exceeding 150°, and the whole poured into water as soon as solution had been effected, a white precipitate was obtained which on purification Erom acetic acid proved to have the composition Cl0HO,NJ,CI7. The filtrate from this precipitate, on addition of am- monia in excess, yielded 2-amino-3 : 4 : 5-trichloropyridine. It was, moreover, found that as the heating was continued for a greater length of time the yield of the substance C,,HO,N,Cl, dimin- ished and that of the 2-amino-3 : 4 : 5-trichloropyridine increased until, in the maximum, a theoretical yield of the latter mas obtained.When the substance, after being brought into solution, was rapidly raised to the boiling point and boiled, the products obtained were penta- chloropyridine, hydrogen chloride, and carbon dioxide. A t the same time, the liquid remained perfectly colourless, and contained 2-amino- 3 : 4 : 5-trichloropyridine in solution. (4) When-the compound Cl,HN,CJ1, is heated alone under diminished pressure, it melts, and at a higher temperature decomposes, yielding chlorine and pentachloropyridine. Nothing of a crystalline character has so far been recovered from the residue. ( 5 ) A similar experiment was carried out with the substance C,,HON,CI,, obtained from the parent compound by recrystallisation from acetic acid.I n this case also, free chlorine was given off and pentachloropyridine distilled over. The experiment was Htopped at an earlier stage than in the preceding one, and before complete decomposition had been effected. The residue, dissolved in acetic acid, on cooling yielded crystals melting at 225O and haviag the composition C,,HON,C17. (6) The same substance, C,oHON,C17, was also obtained by reduc- tion of the compound C,,HN,Cl1, by means of anhydrous stannousTHE CHLORINE DERIVATIVES OF PYRIDINE. PART VII. 901 chloride in acetone solution, and subsequent recrystallisation of the reduced product from acetic acid. From these facts, the following appear to be legitimate deductions. I. That the compound C,,BN,Cl,, consists of two pyridine nuclei linked by the 2-position of the one (which for reference may be callcd the cc ring) t o the nitrogen atom of the other ( b ring) (compare 2 and 3, above). 11.That the hydrogen atom of the compound C,,HN2C11, occupi3s the 6-position in the cc ring. 111. That the b ring, since it is capable of yielding pentachloro- pyridine, must contain a t least six chlorine atoms, as shown by the formula, c1 The two additional atoms of chlorine contained in the molecule which are still unaccounted for in this formula are regarded as being united to the 6 ring for the following reasons. 1. The oxy-derivative of the formula C,,HON,CI, yields, on heating either peiitac hloropyridine, or a compound, Cl,HON,CI,, according to the conditions of the experiment.The latter, with sulphuric acid, yields 2-amino-3 : 4 : 5-trichloropyridine, but cannot be made to yield pentachloropyridine by any of the reactions mentioned above. 2. The compound C,,H0,N2Clr, obtained by the action of sulphuric acid on the parent substance C,,HN,Cl,,, may be made t o yield %amino- 3 : 4 : 5-trichloropyridine, but no pentachloropyridine. It may be observed that when decomposition takes place i t has only hitherto been possible, in the same change, to isolate derivatives from one ring which throw any light on the constitution of the compounds, (the cleavage of the molecule following the line a or p), as is shown in the quantitative experiments described later. The chief derivative of the cc ring is 2-amino-3 : 4 : 5-trichloropyridine ; of the b ring, pentachloropyridine.It is possible, and even probable, that there are tautomeric forms of the compound. With this reserva- tion, the changes and forrnulte described above may be represented in the following may (p. 902) : VOL. LXXIX. 3 Q902 SELL AND DOOTSON: 0 c1 / \ Cl 0 / \ EXPERIMENTAL. Interaction with Watei*.-A quantity of the substance, CloHN,CIl,, weighing 0.7925 gram was heated on the water-bath with 50 C.C. of water for 3 hours and then filtered. The filtrate, after neutralisation with pure chalk, was found to require 29 C.C. of N/lO silver nitrate for complete precipitation. This indicates that, by interaction with water, 100 grams of the compound give 13.35 grams of hydrogen chloride. The equation C,,HN2CI,1 + H,O = CloHON2CI, + 2HC1 requires the production of 13-63 grams of hydrogen chloride from 10 0 grams of the compound.Interaction, with Alcohol.-The parent substance, C1,HN2CIll, dis solved in boiling alcohol, on cooling deposited crystals melting at 171-172° (uucorr.) which were analysed with the following results : 0.5790 gave 0.5250 GO, and 0.0127 H,O. C = 24.73 ; H = 0.24. CloHON,C19 requires C = 24-82 ; H = 0.21 ; C1= 65-86 per cent. Intermtion with Benxoic and Acetic Acids.--In the case of benzoic acid 2 grams of the acid were mixed with 10 grams, or rather more than the theoretical quantity, of the chlorinated derivative, and the mixture distilled from a metal-bath. The distillate, which weighed 2.3 grams, 0.2200 ,, 0.5870 AgC1. C1= 65.99.THE CHLORINE DERIVATIVES OF PYRIDINE.PART VIl. 003 was almost pure benzoyl chloride, as shown by its boiling point and general properties, and was gradually resolved by interaction with water into a solid mass of crystals of benzoic acid. The residue left in the distillation flask was recrystallised from acetic acid and was found, by its melting point and general character, to be identical with the product formed by interaction of the substance CloHN2Cl,, with water or alcohol. The equation Cl0HN2Cll1 + C,H,*CO,H = C,H,*COCl + CloHON2Cl, + HC1 requires that 2 grams of benzoic acid should produce 2.3 grams of benzoyl chloride, so that the yield obtained is seen to be quantitative. When acetic acid was substituted for benzoic acid in the above experiment, a distillate was obtained from which acetyl chloride was isolated by fractionation.Interaction with Sodium Hyclroxicle.--Since the parent substance C,,HN,Cl,, invariably yields the monoxy-derivative, C,,HON,Cl,, on treatment with water as shown above, the latter substance was used in this experiment, Ten grams of this material mere treated with an excess of dilute sodium hydroxide (1 in 10) and distilled with steam until nothing further was carried over. The aqueous distillate on cooling deposited the calculated quantity of 2-amino-3 : 4 : 5-trichloro pyridine, recognised by its melting point (159-160" uncorr.), and a nitrogen determination. 0.3827 gave 46.7 c.c.-nitrogen a t 10' and 764 mm. So far, nothing crystalline has been isolated from the contents of the distillation flask. Interaction with Xulphuric Acid containing 80 peg* cent.of H2S04.- The first product of the interaction of sulphuric acid on the parent substance under the conditions tried is the compound C,,HON,CI, in all cases. Ten grams of the latter were heated to incipient boiling with 100 C.C. of acid, but not boiled. Hydrogen chloride was freely evolved, and on cooling the mass mas poured into several times its volume of water. The precipitate mas collected, washed, and dried, and was found to weigh 1.6 grams. On recrystallisation from glacial acetic acid, this compound WRS obtained in large, lustrous cubes which melted a t 146-1 47" (uncorr.), and furnished the followiiig numbers on analysis : N = 14.11. C,H3N,Cl, requires N = 14.20 per cent. 0.3149 gave 0.3195 CO, and 0.0067 H20.0.2905 ,, 17.4 C.C. nitrogen a t 17" and 750 mm. N = 6.05. C = 27.73 ; H = 0.23. 0,1546 ,, 0.3603 AgC1. C1=57*66. C,oH0,N,C17requiresC=27m90; H=Os23;N=6.51;C1=57*S5 percent. The filtrate from the above, on being made alkaline with ammonia, 3 Q 2904 SELL AND DOOTSON: deposited a bulky crop of filamentous needles, weighing 3.2 grams after washing and drying. These, on recrystallisation and subsequent analysis, proved to be 2-amino-3 : 4 : 5-trichloropyridine, melting at 159-160° (uncorr.). A nitrogen determination was made, with the following result : 0.2192 gave 27.5 C.C. nitrogen at 22' and 762 mm. N = 14.25. C,H,N,CI, requires N = 14.20 per cent. On calculating the weight of the precipitate above into the corre- sponding weight of the material which was originally taken (1.6 grams corresponds to 1.8 grams), and subtracting this from the 10 grams used, it will be seen that 8.2 grams of the compound C,,HON,Cl, underwent the more complete decomposition.This amount should yield theoretically 3.3 grams of aminotrichloropyridine, as against 3*2 grams actually found. I n a second experiment, 10 grams of the compound were heated with 170 C.C. of 80 per cent. sulphuric acid in a distillation flask immersed in a metal-bath, the temperature being gradually raised to 160' and maintained there for 45 minutes. On cooling, the contents of the flask were distilled with steam until practically nothing further was carried over. From the aqueous distillate, 1.3 grams of penta- chloropyridine were obtained by filtration. The contents of the distilling flask deposited nothing on standing for 24 hours, but on addition of ammonia yielded a crop of crystals of 2-amino-3 : 4 : 5-trichloropyridine, which, after washing and drying, weighed 2.8 grams.The latter weight is the theoretical yield of aminotrichloropyridine from 6.8 grams of the substance C,,HON,Clg taken. The material not thus accounted for, 3.2 grams, should theoretically yield 1.6 grams of penta- chloropyridine, as against 1 *3 grams actually obtained. A further experiment, in which the interaction of sulphuric acid with the compound C,,HON,Cl:, was studied, showed by its yielding 2-amino-3 : 4 : 5-trichloropyridine that the former is essentially a derivative of the parent substance CloHN,Cl,,, from which it has been obtained by reduction with stannous chloride and subsequent recrys- tallisation from acetic acid, as also by partial decomposition by heat of f i e hydrolysed product, Cl,HON,C19.Influence of Heat .-The parent substance, C,,HN,Cl,,, was heated in a distillation flask with a wide delivery tube immersed in a metal-bath and under a pressure of 15-20 mm. Beyond melting, no change was observed to take place until the temperature of the bath reached 230-240c, when an oil distilled over which solidified in the delivery tube. As the temperature of the bath approached 260°, the amount of the distillate increased, and the apparatus was full of chlorine. On every occasion a t this stage a slight explosion was noticed, which wasTHE CHLORINE DERIVATIVES OF PYRIDINE. PART VII. 905 succeeded by an increased flow of liquid i n the delivery tube.The temperature of the bath was slowly raised t o 300°, when the experi- ment was stopped. The residue, which was light brown in colour and showed no traces of charring, was completely soluble in glacial acetic acid, imparting t o it an intense greenish-yellow fluorescence, but nothing crystalline could be obtained from it. The distillate gave a very pure specimen of pentachloropyridine, identified by its melting point (1 24-1 25' uncorr.) and by a chlorine determination. 0.1296 gave 0.3700 AgC1. C1= 70966. C,KCl, requires GI = 70.51 per cent. A repetition of the above experiment in which the temperature of the bath was not allowed to exceed 270' led to precisely similar results. In view of the foregoing, it became of interest to examine the effect of heat on the oxy-derivative of t h e original substance.With this object, 20 grams of the compound C,,HON,Cl, were heated in a similar way, the condenser in this case containing crystals of potassium iodide moistened with water. The volatile products were the same, namely, chlorine (which, of course, reacted in part with the potassium iodide) and pentachloropyridine. The reaction was in this case stopped when the temperature of the bath reached 2 70° and the pentachloropyridine was still coming over. The residue was recrystallised from acetic acid, and the first crop of crystals, melting at 225-226' (uncorr.), was analysed, with the following results : 0,5815 gave 0.6317 CO, and 0*0111 H,O. C=29.62; H=0*21. Cl,HON2C17 requires C = 29.07 ; H = 0.25 ; C1= 60.00 per cent. It is thus seen that the compound C,,HON,Cl,, obtained by incom- plete chlorination of pyridine hydrochloride (Trans., 1899, 75, 9SO) and by the reduction of the parent substance, C,,HN,CI,,, by stannous chloride and subsequent crystallisation from acetic acid, may also be obtained by heating the oxy-derivative, ClloHON,C19 Reduction by mecins of Stccnnozcs ChEoride.-The compound CloHN,CI,l was dissolved in acetone containing an equal weight of anhydrous stannous chloride. The mixture, when heated on the water-bath in a refluv apparatus, reacted energetically. The product obtained on dilution was recrystallised from acetic acid, from which it separated in rectangular prisms melting a t 223- 224' (uncorr.). A chlorine deter- mination furnished the following numbers : 0.3405 ,, 0,8246 AgCl. U1= 59.82. 0.2098 gave 0.5050 AgCI. C1= 59-75. C,,HON,Cl, requires C1= 60.00 per cent. UNIVERSITY CHEMICAL LABORATORY, CAMBRIDGE.

ISSN:0368-1645    

DOI:10.1039/CT9017900899

出版商:RSC    

年代:1901

数据来源: RSC

摘要:

906 DORAN: THE ACTION OF LEAD THfOCYANATE ON THE XCIV.-The Action of Lead Thiocyanute o n the Chlo?-o- carbonates. Part IL Cwboxymethyl- and Carb- oxyumyl-thioca?.bimides awl their Dekvatives. By ROBERT ELLIOTT DORAN. IN the Society’s Transactions for 1896 (p. 324, et seq.), the author described the preparation and properties of carboxyethylthiocarbimide, and dealt with the further proof which it afforded of the generic character of the interaction, discovered by Miquel, which occurs when certain of the acidic chlorides are heated under suitable conditions with lead thiocyanate. The present communication is chiefly con- cerned with the homologous methyl compound, and as the methods of preparation were usually carried out in the same way as those described in Part I., briefer details will be sufficient.Preliminary experiments showed that there was no apparent sign of interaction when methyl chlorocarbonate alone was heated with lead thiocyanate, and only traces of a thiocarbimide could be detected when the mixture was diluted with benzene and again heated. When, however, a mixture of benzene and toluene was used as solvent for the chlorocarbonate, interaction took place fairly readily on heat- ing, and was completed, as a rub, after ten to twenty minutes’ boil- ing. Working on a larger scale, 20 grams of methyl chlorocarbonate were dissolved in a mixture of equal volumes of benzene and toluene, and added, in a flask, to a quantity of dry lead thiocyanate about one and a-half times that required by the equation : 2CH,O*COCl + Pb(SCN), = 2CH30*CO*NCS + PbCl,.The flask was connected with a reflux apparatus, and the mixture, with frequent shaking, cautiously heated to boiling. Interaction set ih rapidly, as was indicated by a change of colour in the liquid and in the lead salt, but brisk ebullition had to be maintained for upwards of twenty minutes before the liquid (now bright yellow), when cooled and allowed t o clear by subsidence, was found to be free from chlorine. The lead chloride and unchanged thiocyanate were removed by filtra- tion, washed with benzene, and the filtrate further diluted with this solvent until, assuming an approximately quantitative yield, each C.C. should contain 0.5 gram of the thiocarbimide. From this solution, some of the derivatives to be described presently were prepared. It is desirable to note here that the yields of the thiocarbimide, as esti- mated from the yields of its derivatives, only approached that theoretically obtainable on one or two occasions.Much greater diffi- culty has, in fact, been experienced in getting complete interactionCHLOROCARBONATES. PART Ir. 907 between methyl chlorocarbonate and lead thiocyanate than between its ethyl homologue and the same salt. So far, the cause of this hae not been ascertained, but it has been noticed occasionally that the formation of the thiocarbimide apparently stopped when rather less than half the chlorocarbonate taken had undergone change, No variation in the amount of solvent used, or in the relative proportions of its constituents, or the use of toluene alone, with the object of getting a higher temperature, appeared to have any appreciable effect in completing the interaction ; whilst the possible influence of mass and of surface coating of the thiocyanate was eliminated as far as possible, both by the use of a very large excess of the lead salt and by filtering off that partly acted on, replacing it by a fresh charge and reheating.An extecded series of experiments was made with several of the other thiocyanates, those of silver, mercury, ammonium, and potassium being tried, and the last-named was the only one that gave anything like satisfactory results. It has been found that when methyl, ethyl, or amyl chlorocarbonate is diluted with dry benzene and allowed to stand in contact with dry, finely-powdered potassium thiocyanate, interaction commences at the ordinary tem- perature on the third or fourth day (when the clear liquid becomes faintly yellow and gives a slight but distinct black precipitate with ammoniacal silver nitrate), and contiuues until, after a period of two to three months, it approaches completion.Unfortunately, however, whilst there is still unchanged chlorocarbonate present, decomposition sets in, accompanied by the formation of mercaptans, chlorides, carbon dioxide, and an amorphous, orange-yellow solid, insoluble in water, which has not yet been examined j nevertheless the greater part of the chlorocarbonate used undergoes change in accordance with the equation : R’O*COCI + KSCN = RO*CO*NCS + KCI. Solutions of carboxymethylthiocarbimide obtained in this way have been used in the preparation of some of the derivatives to be described later.The action of heat appears to have little effect in increasing the rate at which the change takes place, unless the opera- tion is conducted under pressure, when, in two experiments made at the temperature of the water-bath, it resulted in decomposition with explosive violence. On account of the poor yields, and partly on account of the fairly complete examination of the corresponding ethyl compound (Zoc. cit.), no attempt was made to isolate carboxymethylthiocarbimide. Its properties, as determined in solution, in respect to its action on desulphurising agents, and lack of any action on ferric chloride, are identical in every way with those of its homologue, EtO-CO*NCS.It908 DORAN: THE ACTION OF LEAD THIOCYANATE ON THE was found that the presence of upwards of 50 per cent. of unchanged chlorocarbonate did not affect the preparation of the derivatives described, although of course it resulted in the simultaneous forma- tion of the urethanes and hydrochlorides corresponding to the indi- vidual amines used, as well as the required sulphuretted compound, in accordance with the general equation, MeO*COCl + 2R*NH, = MeO*CO*NHR‘ + R’*NH,,HCl. AS the hydrochlorides thus formed are practically insoluble, and the urethanes usually freely soluble in benzene, whilst the thiocarb- amides and thioureas as a rule occupy a conveniently intermediate position, the separation and purification of the last, when obtained in sufficient quantity, were readily effected, Turning now to the derivatives themselves, it will prevent un- necessary repetition to state beforehand that they were all prepared in the same way, by adding the bases, dissolved in benzene or alcohol, to the benzene or benzene-toluene solution of the thiocarbimide, in the proportions required by the equation, R*NH, + MeO*CO*NCS = MeO*CO*NH*CS*NH*R’.Interaction occurred immediately with development of heat, and usually with separation of a solid consisting of the required thiocarb- amide or thiourea, or mixtures of them with the hydrochloride of the base used, in those cases where the parent substance was not obtained free from unchanged chlorocarbonate. In all instances where no definite yield is mentioned, this condition prevailed in a greater or less degree.Aromatic Derivatives. ~b-Carboxymet~yZphenyZt~~~ocur~~m~de, CH,O*CO*N H.CS.NH*C,H,. --This substance was obtained from aniline and the thiocarbimide. When recrystallised from alcohol, it formed long, white needles melting at 158’ without decomposition. 0.2008 gave 0.2248 BaSO,. On analysis : S = 15.39. C,H,,O,N,S requires S = 15.25 per cent. The compound is freely soluble in hot, but only sparingly so in cold, alcohol or benzene, and is sparingly soluble in hot water. I n alcoholic solution, it is readily desulphurised on warming with neutral silver nitrate, or on boiling with alkaline lead tartrate, and at once in the cold with alkaline silver nitrate. a b- Car box y rneth y Zbenx ylthiocarbamide, CH,O* CO*NH*CS*NH*CH,*C,H,. -Only a very poor yield of this derivative was obtained, and whenCHLOROCARBONATES. PART 11.909 recrystallised from aqueous alcohol, from which it separated in tufts of needles, it melted a t 134' without decomposition. 0.124 gave 0.130 BaSO,. Cl,H120,N2S requires S E= 14.3 per cent. I t is freely soluble in hot, and moderately so in cold, alcohol or benzene, but is insoluble in water. Its alcoholic solution gives a white precipitate, blackening on heating, with neutral silver nitrate, an immediate black precipitate with the ammoniacal nitrate, and is slowly desulphurised on boiling with alkaline lead solution. ab- CwboxymetJ~ yl-o-to Zy It Jhioccwbccmicle, S= 14.41. CH,O *CO*NH*CS*NH*C,H,*CH,. -The yield of the crude product amounted to 96 per cent. of the theoretical.The pure substance melted at 172" without decomposition. 0.1999 gave 0.2092 BaSO,. Ul,Hl,0,N2S requires S = 14-30 per cent. The compound is moderately soluble in hot, and sparingly so in cold, benzene or alcohol, separating from the former in needles and from the latter in feathery plates. With desulphurising agents, i t behaves like the phenyl derivative. S = 14.38. It is insoluble in water. ab-Cn~box~methy~-p-to~y~th~ocarbc~m~de, CHsO*CO*NH*CS*NK*C,H;CH,. -A 35 per cent. yield mas obtained in the form of thick, short prisms melting a t 158" without decomposition. S= 14.44. 0.20 gave 0.2101 BaSO,. For all practical purposes, the properties of this compound are ab-Curbox ymeth y l-a-naphtJ,? y lthiocarbccmide, C,oH,202N2S requires S = 14-30 per cent. identical with those of the o-derivative.CH,0*CO*NH-CS*NH*C,,H7. -This compound crystallises from alcohol in tufts of long, flexible needles melting at 193' with copious effervescence. 0,2212 gave 0-20 BaSO,. C,,H120,N2S requires S = 12.32 per cent. The substance is moderately soluble in hot, and sparingly so in cold, benzene, rather sparingly soluble in hot, and. nearly insoluble in cold, alcohol, and is insoluble in water. The behaviour of this and the following compound, with the usual reagents for the removal of sulphur, is practically the same as that of the tolyl derivatives. S = 12-43. ab-Curbox ymethy l-P-naph th y Jthiocarbamide, CH,O*CO*NH*US*NH*C,,H~. .-By recrystallisation from mixed alcohol and benzene, this compound910 DORAN: THE ACTION OF LEAD THIOCYANATE ON THE was obtained in microscopic needles melting a t 184' with decom- position.0,2014 gave 0,1822 BaSO,. It is freely soluble in hot, and moderately so in cold, benzene, sparingly soluble in hot, and nearly insoluble in cold, alcohol, and very sparingly soluble in hot -water. S= 12.43 per cent. B'c8tty Derivatives. ab-Car60xyrrzethyZ1nethyZthiocarbanaide, CH,O CO*N H* CS*NH* CH,. - This compound was obtained in the form of fine, white needles melting a t 146' without decomposition. 0.2028 gave 0.3219 BaSO,. S=21*8. It is moderately soluble in hot, and sparingly so in cold, alcohol, benzene, or water. Its alcoholic solution gives a white precipitate with neutral silver nitrate, which blackens on heating; it is at once desulphurised by the ammoniacal nitrate, but only darkens slightly on prolonged boiling with alkaline lead solution.ab-CarboxymethyZetl~yZthiocarbamide, CH,O*CO*NH*CS*NH*C,H,, occurs in tufts of white, feathery needles melting at 86' without de- composition. C,H,@,N,S requires S = 21 -63 per cent. 0.203 gave 0.295 BaSO,. S = 19.9. C,H,,O,N,S requires S = 19.76 per cent. The compound is freely soluble in hot or cold alcohol or benzene, moderately so in hot, but sparingly so in cold, water, and is nearly insoluble in cold light petroleum. With desulphurising agents, i t reacts like the preceding compound. ab-Carboxymeth y Ziso butyZthioca?*bamide, CH,O *CO * NR CS-NH C,H,. -This substance, of which only a very poor yield was obtained, crys- tallises from light petroleum in long prisms melting at 8 3 O without decomposition. 0.153 gave 0.1895 BaSO,.S- 17.02. C7H,,0,N,S requires S = 16.85 per cent. It is freely soluble in hot or cold alcohol or benzene, moderately so in hot, and only sparingly so in cold, light petroleum. It behaves like the methyl and ethyl derivatives with lead and silver salts. Carboxymetl~yZtiLioecl.ea, CH,O*CO*N:C(NH,)*SH.-On passing a stream of ammonia through a quantity of the benzene-toluene solution of the thiocarbimide, vigorous action occurred: accompanied by the evolution of heat and traces of hydrogen sulphide. A little solidCHLOROCARBONATES. PART 11. 911 separated while the liquid was still hot, and on cooling a considerable crop of crystals was obtained which, when collected, washed with benzene and recrystallised, first from water and then from alcohol, from which it separated in short prisms,.melted a t 166' with copious effervescence, the gas evolved being apparently methyl mercaptan.0.20 gave 0.348 BaSO,. S=23*92. C,H,O,N,S requires S = 23-89 per cent, The substance is moderately soluble in hot, sparingly so in cold, benzene, freely but slowly soluble in hot, and sparingly so in cold, alcohol, moderately so in hot, and nearly insoluble in cold, water. Its aqueous solution is readily desulphurised by the usual reagents, and gives a very- fine mirror of lead sulphide with alkaline lead tartrate. Trisubstituted Thioweas. Of these, three were prepared, from piperidine, and methyl- and benzyl-anilines, but only one of them, that derived from the first- named base, was obtained in quantity sufficient for satisfactory identification, CH,O* CO *N: C (SH) *NC,H,,.- The yield of the crude substance amounted to 11 per cent. of the theoretical. When purified by recrystallisation, firstly from mixed benzene and light petroleum, secondly from the latter solvent alone, and thirdly from water, it melted a t 97". 0.205 gave 0.2355 BaSO,. S= 15.8. C,H,,O,N,S requires S = 15.77 per cent. It is very freely soluble in benzene, alcohol, ether, chloroform, or acetone; but only sparingly so in hot, and nearly insoluble in cold, water or light petroleum. Its alcoholic solution is not visibly affected by prolonged boiling with alkaline lead solution, and only darkens slightly under the same conditions with ammoniacal silver nitrate. CarboxymethyZpiperidylthiowrea, Car box9 met hy @hen9 lsemit hiocar baxide , CH,O* CO*NH* C( SH) : N NH* C,H,.--Vigorous action occurred when phenylhydrazine, dissolved in alcohol, was added to a benzene-toluene solution of carboxymethyl- thiocarbimide. A solid separated almost at once, and by recrystal- lisation from alcohol was eventually obtained pure in the form of white, glistening plates melting at 180°, and remelting at the same temperature. S= 14.22 C9H,,0,N,S requires S = 14023 per cent. 0.2078 gave 0.215 BaSO,. The substance is moderately freely but slowly soluble in hot, and912 DORAN: THE ACTION OF LEAD THIOCYANATE ON THE is nearly insoluble in cold, alcohol, sparingly so in hot benzene, and insoluble in water. Its alcoholic solution, with neutral silver nitrate, gives a white silver salt which blackens slowly on heating, and shows the usual reactions characteristic of a hydrazine derivative with copper sulphate and ferric chloride.lirhiocacl.bcsmates. Three of these were prepared by mixing an excess of the corre- sponding alcohols with a benzene solution of the thiocarbimide. They were obtained by allowing the benzene and excess of alcohol to evap- orate spontaneously, and were purified by recrystallisation from light petroleum in the case of the first two, and from aqueous alcohol in the case of the benzyl compound. In alcoholic solution, they all gave white silver salts, which blackened at once on heating, after the addi- tion of ammonia. Meth y I Carboxymeth?lltl~io~r~~mate, CH,O* CO*NH* CS 0. CH,. - White, feathery needles melting at 46O.0,2042 gave 0.3198 BaSO,. S = 21.53. Ethyl Cai*boxymethyZtliiocarbamate, CH,O*CO*NH*CS*O*C,H,.-Long 0.205 gave 0.296 BaSO,. Benxyl Carboxymetlbylthiocarbamate, CH30*CO*NH*CS*O*CH,*C,H,. 0.2084 gave 0.220 BaS04. C,H,O,NS requires S = 21.49 per cent. needles melting a t 83’. S = 19.85. C5H,0,NS requires S = 19-65 per cent. -Tufts of fine, creamy-white needles melting at 103O. S = 14.51. Cl,Hl,O,NS requires 14.24 per cent. I n Part I of this communication, to which reference has already been made, it was shown, when dealing with the “constitution o€ nitrogen bases and isomerism,” that Seidel’s so-called “ethyl isophenyl- thioallophanate ” ( J . yr. CIbem., 1885, [ii], 32, 261) was identical with the author’s s-carbox yet h ylp h en ylt hiocarbamide, and that Seidel’s statement that the group RO*CO* was ‘‘ negative ” t o R’CO, and could be expelled by it from compounds of the type specified, was incorrect, I n fact, the very opposite was established in the case then under investigation, since it was found that carboxyethylphenylthiocarbamide remained unchanged after heating with a large excess of acetyl chloride, whilst the converse change was readily effected by heating acetylphenylthio- carbamide with ethyl chlorocarbonate,CHLOROCARBOISATES.FART 11. 913 the product being in every respect identical with that obtained by the direct union of aniline with carboxyethylthiocarbimide. Since this result was published, the author has prepared several other carboxy- ethyl derivatives by heating various acetylthioureas with EtO*COCl, and, in the course of the present investigation, has further established the positive character of the group R'O*CO, so far as the group CH,-CO* is concerned, by the following experiment.Five grams of methyl chlorocarbonate were added to 3 grams of acetylphenylthiocarbamide in a flask and the mixture heated on the water-bath under a reflux con- denser for 20 minutes, until all solid had disappeared. Acetyl chloride, hydrogen chloride, and traces of hydrogen sulphide were evolved just as in the experiment made with ethyl chlorocarbonate. The contents of the flask solidified on pouring out into a dish, and the solid matter, when freed as far as possible from a rather sticky mother liquor (containing acetyl chloride, methyl acetate, and un- changed chlorocarbonate), and purified by recrystallisation from alcohol, was obtained in fine, white needles melting at 157-15S0, and giving on analysis, S = 15.34 per cent.(calc. S = 15-25 per cent.). The interaction is represented by the equation : PhNH*CS*NH*CO*Me + MeO-COG1 = PhNH*CS*NHCO*OMe + MeCOCI- Acetyl-o- and y-tolylthiocarbamides give iden tical results under similar treatment; in fact, the method is probably a generic one, whereby thiocarbamides and thioureas containing the group R'O*CO* may be obtained from the corresponding acetyl compounds. As disposing of all the work which he intends doing for the present with thiocarbimides derived from the chlorocarbonates of the fatty series, the author would briefly describe here the preparation and pro- perties of certain derivatives of carboxyamylthiocarbimide.The parent substance was obtained by slow interaction, at the ordinary temperature, between finely-powdered and well-dried po tass- ium thiocyanate and carboxyamylcblorocarbonate dissolved in pure anhydrous benzene. The experiment extended over three months, air having access all the time through a capillary opening to the vessel in which it mas made; but the admission of moisture was prevented, as far as possible, by a long column of calcium chloride in a drying tube. At the end of this time, the clear solution (which left no appreciable solid residue on evaporation to dryness), whilst desulphurising copiously with alkaline lead and silver solutions, still reacted rather strongly for chlorine; but as there were obvious indications that decomposition had commenced, the experiment was stopped, the liquid filtered from the potassium chloride (formed in accordance with the9 14 ACTION OF LEAD THIOCYANATE ON THE CHLOROCARBONATES.gen era1 equation already given) and excess of unchanged potassium thiocyanate. It was then divided into equal parts, and the following derivatives were prepared by adding the corresponding amines, in alco- holic solution, until no further sign of interaction was observed. Very poor yields were obtained, but these were quite suficient for satisfactory identification : ab-Cadoxyam yZphenylthiocarbamide, C,H,,O* C0.N H*CS*NH C,H5. -Fine white needles from light petroleum, melting a t 97-98", without decomposition. 0.2036 gave 0.1'790 BaS0,.C,,H1,O,N,S requires S = 12-04 per cent. ab-Cccrboxyamyl-o-tolylthiocarbamide, C,H,,O*CO*NH*CS.NH*U,H?. -This compound also crystallises in fine, white needles, closely resembling the phenyl derivative and melting at 96-97O without decomposition, S = 12.08. 0.2082 gave 0.1734 BaSO,. Both these compounds gave the usual reactions with lead and silver salts characteristic of the class they represent. They are very freely soluble in benzene or hot alcohol, and moderately so in cold alcohol, from which they separate as oils on the addition of water, but are practically insoluble in cold light petroleum. An attempt was made to prepare carboxyamylthiourea by passing dry ammonia through another portion of the solution, and a white, crystalline produot was obtained melting at 56-57O, which in alcoholic solution clesulphurised with neutral and ammoniacal silver nitrate, and gave a mirror of lead sulphide on boiling with alkaline lead tartrate. The mean of two sulphur determinations was, however, S = 9.702 per cent., as against 16*S5 required for CSN,H,*CO,*C,H,,.The product is probably a mixture of this compound with amyl carb- amate, resulting from interaction between ammonia and the unchanged amyl chlorocarbonate present, but the quantity obtained was too small to permit of their separation. The two fully identified derivatives furnish an interesting example of the effect of the introduction of the higher alkyl group (C,H,, in place of C2H5 or CH,) on the melting point, for whilst the differences between the melting points of the phenyl and o-tolyl derivatives of carboxymethylthiocarbimide and carboxyethylthiocarbimide are 1 4 O and 2 2 O respectively, in the present case there is only a difference of 1". They are sufficiently close, in fact, to suggest, if without analytical data, the barely possible accident of using the same amine for both preparations. When mixed, however, in equal portions, the melting S = 11 -45. C,,H,,O,N,S requires S = 11 -44 per cent.A LABORATORY METHOD FOR THE PREPARATION OF ETHYLENE. 915 point of the two compounds (96-97' and 97-9s') drops smartly to 84O. An attempt has been made to tabulate the melting points of the compounds described in this and the previous communication, and some interesting relationships have been observed, particularly amongst the isomeric thiocarbamides and thiocarbamates. The author does not intend to deal with this portion of his subject at present, but hopes shortly to lay before the Society an account of some derivatives of ethoxalglthiocarbimide which have been prepared, and to extend the present research to the action of lead or other thiocyanates on phenyl chlorocarbonate. QUEEN'S COLLEGE, CORK. CHEMICAL DEPARTMENT,

ISSN:0368-1645    

DOI:10.1039/CT9017900906

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年代:1901

数据来源: RSC

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A LABORATORY METHOD FOR THE PREPARATION OF ETHYLENE. 915 XCV.-A Laboratory Method for the Preparation of Ethy Zene. By G. S. NEWTH. THE common method for obtaining ethylene by means of alcohol and sulphuric acid, and all its attendant drawbacks of charring, frothing, and the simultaneous evolution of carbon dioxide anti sulphur dioxide, are too well known to require more than a passing allusion. Even when pure alcohol is employed, the trouble is only lessened, not removed. All these inconveniences, however, may be entirely obviated by the simple plan of substituting tribasic phosphoric acid for the sulphuric acid. The formation of phosphovinic c~cid, a compound analogous to suZpho- vinic acid, by the action of phosphoric acid upon alcohol, was observed by Lassaigne as far back as 1820 ( A m .Chim., 13, 294). The fact that under certain conditions ethylene is evolved by the action of phosphoric acid on alcohol was recorded by Pelouze (Ann. China., 1833, 52, 37), who states that when the acid is very cohcentrated, having the consistency of thick syrup, and is mixed with one-fifth of its weight of alcohol, a brisk effervescence results, and there is produced a large quantity of ‘‘ bicarburet of hydrogen ” ; 6‘ oil of wine,’’ is also formed, and the mixture, he says, becomes dark- coloured owing to the separation of carbon in the form of black flocks, Although, therefore, there is no new chemical decomposition involved in the process I am about to describe, so far as I am aware no one has previously developed a practical method for obtaining916 NEWTH: A LABORATORY METHOD FOR THE ethylene in quantity based upon the action of phosphoric acid on alcohol.About 50 or 60 C.C. of syrupy phosphoric acid of sp. gr. 1.75 are placed in a small Wurtz flask of about 180 C.C. capacity. The flask is fitted with a cork’carrying a thermometer and a dropping tube, the end of the latter being drawn out to a fine tube, and reaching to the bottom of the flask. Phosphoric acid of sp. gr. 1.75 boils at a temperature about 160’. It is heated in the flask and allowed to boil for a few minutes until its temperature reaches 200°, when ethyl alcohol is allowed to enter drop by drop. Ethylene is immediately disengaged, and by maintaining the temperature between 200’ and 220’ a continuous supply of the gas can be obtained even from so small an apparatus at the rate of 10 to 15 litres per hour.The gas should be conducted through a small Woulf ’s bottle (100 t o 150 C.C. capacity) standing in a vessel of ice, in which an aqueous liquid collects containing a small quantity of ether, unde composed alcohol, and traces of an oily liquid-presumably the so- called “oi.1 of wine,” referred to by Pelouze. The gas which passes on is practically pure ethylene, and contains no trace of carbon dioxide, and of course no sulphur dioxide, It is absorbed completely by fuming sulphuric acid. There is no charring or separation of carbon in the re- action flask, for although tho liquid assumes a brownish colour, it remains perfectly clear. The mixture does not evince any tendency to ‘ I froth up,” hence the operation may be carried out in small vessels.The process appears to be continuous, and so long as the supply of alcohol is maintained, the operation will go on without attention for appar- ently an indefinite period. I n one experiment, the action was allowed to continue for several hours a day for a whole week, during which time several hundred litres of ethylene had been generated by the same quantity, 50 c.c., of phosphoric acid. It is noticed that after a few days the glass vessel shows signs of being acted on by the phosphoric acid ; it is advisable, therefore, to protect the thermometer by wrapping the extremity of it in a strip of platinum foil. Ordinary methylated spirit may be used instead of pure alcohol, but in this case the ethylene will contain more or less methyl ether mixed with it, which, however, can be dissolved out by water. My experiments do not entirely confirm the results recorded by Pelouze; that is t o say, under no conditions do I obtain any depo- sition of carbon.Even when alcohol is added to phosphoric oxide itself there is no indication of blackening, although there is a brisk evolution of ethylene. The gas which is given off under these cir- cumstances, however, always contains appreciable quantities of a gaseous phosphorus compound, probably phosphine, which is readily The process may be carried out as follows :PREPARATION OF ETHYLENE. 917 seen by passing the gas through silver nitrate solution. Whether the formation of this gas is due to the presence of impurities in tbe phos- phoric oxide or not is a matter which is still under investigation; the immediate point is that even under these conditions no carbonisation takes place.Glacial phosphoric acid appears to be quite incapable of converting alcohol into ethylene under conditions which are in any way com- parable t o those: just mentioned. Preparation of &thy2 Ethtr. By substituting methyl alcohol for ethyl alcohol in the foregoing process and maintaining the temperature between 200' and 210°, the gas which is evolved is practically pure methyl ether. Specimens of the gas collected over mercury were found to dissolve completely and rapidly in water. By passing the gas through a tube cooled to - 30°, it was wholly condensed to a colourless liquid which boiled at - 23.5' Preparation of Prop y lene . By operating in a similar manner with propyl alcohol, propylene in a state of purity is readily obtained. When the normal alcohol is employed, the temperature necessary to bring about the reaction is about 250°, while with isopropyl alcohol the decomposition proceeds rapidly at 2 10'. As in the former case, the liquid products of the action were col- lected in a bottle cooled by ice or by ice and salt, whilst the gas was condensed in a tube immersed in a bath of solid carbon dioxide and ether. The liquefied gas was found to boil between - 41' and - 38'. The gas from this boiling liquid was passed into bromine, in which it was r'ipidly absorbed, yielding propylene dibromide boiling at 141O. The liquid products of the action were found to consist of an aqueous solution of the alcohol employed, together with small and varying quantities of liquid hydrocarbms. ROYAL COLLEGE OF SCIENCE, LONDOS, SOUTH KENSINGTON, S.W. VOL. LYXIX. 3 R

ISSN:0368-1645    

DOI:10.1039/CT9017900915

出版商:RSC    

年代:1901

数据来源: RSC

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918 RUHEMANN : CONDENSATION OF PHENOLS WITH XCVL-Condensation of Phenols with Esteys of the Acetylene h'egvies. Part V. Homologues of Benxo- y - p yrone By SIEGFRIED RUHEMANN. As has been shown previously (Ruhemann and Stapleton, Trans., 1900, 77, 1179; Ruhemann and Bausor, this vol., p. 470), the esters which are formed by the interaction of the sodium derivatives of phenol and the cresols may be condensed to benzo-y-pyrone (1 : 4- benzopyrone) and its homologues. The extension of this research t o thymol and carvacrol is recorded in this paper. With regard to the nomenclature of the benzopyrone compounds, I follow M. M. Richter's plan, in which the numbering of positions starts with the oxygen atom of the pyrone ring. C6H5* :CH*CO,* C,H5 Ethyl P-Thymoxycinnarnate, I C H CZI * O*C6H3<&37[5, This compound is formed by dissolving sodium (1 at.) in an excess of hot thymol and adding to the hot dark solution ethyl phenylpro- piolate (1 mol.).The reaction takes place with development of heat, and the product, when allowed t o stand, solidifies to a dark resin. This dissolves on being agitated with dilute sulphuric acid and ether; the ethereal layer is then shaken with potash to remove the excess of thymol, and the ether evaporated. The dark residue which remains behind, on distillation in a vacuum, yields a yellowish, very viscous oil which boils at 218-219' under 12 mm. pressure. On analysis : 0.2074 gave 0.5930 CO, and 0-1384 H,O. C,,H,,O, requires C = 77-78 ; H = 7.40 per cent. P-Z'hymoxycinnamic Acid, C6H,*C[O*C6R3( CH,)*C,H7]:CH*C0,H.- The ester is hydrolysed when boiled with alcoholic potash for 3 hours on the water-bath.On adding dilute sulphuric acid to the alkaline solution after evaporation of the alcohol, the thymoxycinnamic acid is precipitated in the form of a resinous product which solidifies on standing, and crystallises from dilute alcohol in colourless prisms. These begin to decompose at 130°, and at 138' melt with evolution of gas; they are insoluble in water, but dissolve readily in alcohol o r ether. P-Thymoxycinnamic acid shows the same behaviour as its lower homologues; sulphuric acid does not effect its condensation to a derivative of 1 : 4-benzopyrone. C = 77-97 ; H = 7.41. On analysis :ESTERS OF THE ACETYLENE SERIES. PART V. 919 0.3055 gave 0.5738 CO, and 0.1252 H20.C19H2005 requires C = 77-03 ; H = 6.76 per cent. The silver salt, obtained as a white precipitate on mixing the solution of the acid in ammonia with silver nitrate, is insoluble in water and melts a t looo. For analysis, it mas dried in a vacuum over sulphuric acid. C = 77.12 ; H = 6.77. 0.46'75 left, on ignition, 0.1245 Ag. Ag = 26.63. C,,H,90,Ag requires Ag = 26.53 per cent. On heating P-thymoxycinnamic acid, i t loses carbon dioxide and yields /3-thymoxystyrene, This distils a t 177-1 78" under 10 mm. pressure as a colourless oil with a pleasant aromatic odour, and at 1 4 O / 1 4 O has the density 019925. After standing for several weeks, it solidifies to a mass of crystals which melt a t 26' and are very soluble in alcohol or ether. On analysis : 0.1967 gave 0.6170 GO, and 0.1405 H20.C = 85.55 ; H = 7.93. C,,H,,O requires C = 55.71 ; H = 7.94 per cent. Action of the Xodium Derivatives of ThymoZ and CiarvacroZ on Ethyl c h ~ 0 ~ 0 fiLnZClrC6te. Ethyl Th ynzoxpfunznrccte, ?y EH*CO,*C,H,, \/-O-C C02*C2H, %K7 The union of bhymol with ethyl chlorofumarate takes place with development of heat when the unsaturated ester (1 mol.) is carefully added t o the solution of sodium (1 at.) in an excess of thymol. The greenish, viscous product which is thus formed is allowed to stand overnight, and, after adding water and a little sulphuric acid, is ex- tracted with ether. The ethereal solution is then freed from thymol by repeatedly shaking i t with potash, the ether evaporated, and the residue distilled in a vacuum.The ester is a yellowish oil which boils a t 194O under 10 mm. pressure, and a t 14'/14" has the density 1,0493. On analysis : 0.1997 gave 0.4940 GO, and 0-1372 H,O. C = 67.46 ; H= 7.63, C,,H,,O, requires C = 67-50 ; H = 7.50 per cent. P I 151 @I Thymoxyfumuric Acid, C3H7*(CH3)C6H3*O*C(C02H):CH*C02H.- 3 ~ 2920 RUHEMANN : CONDENSATION OF PHENOLS WITH This acid is formed from the ester by boiling it with alcoholic potash for about 3 hours. After the alkaline solution has been freed from alcohol by distillation on the water-bath, water is added to the residue, and the solution acidified with dilute sulphuric acid. The solid which is thus precipitated, crystallises from hot dilute alcohol in yellowish needles which melt, not quite constantly, at 215' with evolution of gas, and are scarcely soluble in water.On analysis : 0.2010 gave 0.4680 CO, and 0.1115 €T,O. C=63*30; H=6*16. Cl,Hl,O, requires C = 63.64 ; H = 6.06 per cent. 5-Methyl-8-propyE 1 : 4-6enxopy~one-2-carboxytic Acid, Thymoxyfumaric acid dissolves in cold concentrated sulphuric acid, forming a dark red solution. After standing for 24 hours, this is gradually poured into ice-cold water, when a white precipitate is formed which filters with difficulty, and crystallises from dilute alcohol in colourless, lustrous plates. These melt and decompose at 245O, and are freely soluble in alcohol or ether, but almost insoluble in water. On analysis : 0.2003 gave 0-5015 CO, and 0.1060 H,O. The benzopyrone itself, which is formed on heating the acid, has C=68.28 ; H=5-88.C14H1404 requires C = 68*29 ; H = 5.69 per cent. not been further examined. C,*7 /\ RH*CO,*C,H,. Ethyl Carvawoxyfurnavate, 1 \/I--o-c*co2*c,€€5 CH3 Sodium (1 at.) readily dissolves in an excess of hot carvacrol ; on adding ethyl chlorofumarate (1 mol.) to the brown solution, heat is developed and the colour changes to green. The product is allowed to stand overnight, and, on proceeding as in the previous cases, the ethyl carvacroxyfumarate is obtained as a yellowish oil which distils at 206O under 14 mm. pressure, and at 14*/14O has the density 1.0445. On analysis : 0.2030 gave 0.5020 CO, and 0,1373 H,O. C= 67.44 ; H = 7-51. C,,H,,O, requires C = 67.50 ; H = 7.50 per cent.ESTERS OF THE ACETYLEXE SERIES. PART V. 9 21 ~ 5 1 P 1 The acid, C,H7*(C~,)C,H,*O*C(C0,H):CH*C0,H, obtained frcm the ester on hydroljsis with alcoholic potash, is precipitated from the alkaline solution by means of dilute sulphuric acid as an oil which gradually solidifies.It crystallises from dilute alcohol in yellowish plates which melt a t 175O with evolution of gas, and are readily soluble in alcohol or ether, but only sparingly so in water. Gn analysis : 0.1945 gave 0.4543 CO, and 0.1 060 H,O. C = 63-70 ; H = 6.05. C,,H,,O, requires C = 63.64 ; H = 6.06 per cent. 5-Prop@3-nzeth yl-1 : 4-beizxo~yrone-2-ccc~boxyl~c Acid, Carvacroxyfumaric acid dissolves in cold concectrated sulphuric acid, forming a red solution which, after standing overnight, is poured into cold water, when a white solid is precipitated; this crys- tallises from hot dilute alcohol in colourless prisms which melt and decompose a t 237-238O and are readily soluble in alcohol or ether. On analysis : 0.2028 gave 05082 CO, and 0.1095 H,O. C = 68-34 ; H = 6.00. C,,HI,O, requires C 5-: 68.29 ; H = 5.69 per cent. \/‘co’ %H7 This compound is obtained by heating the acid; i t distils as a yellowish oil which gradually solidifies. The solid cont ains, besides the benzopyrone, a small quantity of the acid, from which it is freed by shaking the ethereal solution of the distillate with potash. On allowing the ether to evaporate a t the temperature of the room, the benzopyrone crystallises in colourless prisms which melt at 59-60’, On analysis : 0.2060 gave 0.5840 CO, and 0.1292 K,O. C= 77.31 ; H= 6.97. C,,H,,O, requires C= 77.23 ; H= 6.93 per cent.922 MADAN: THE COLLOID FORM OF PIPERINE. Propylmethyl-1 : 4-benzopyrone bas a pleasant odour and freely dissolves in nlcohol or ether, but is insoluble in water ; its solution in concentrated sulphuric acid has a faint greenish fluorescence. GONVILLE AND CAIUS COLLEGE LABORATORY, CAMBRIDGE.

ISSN:0368-1645    

DOI:10.1039/CT9017900918

出版商:RSC    

年代:1901

数据来源: RSC

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922 MADAN: THE COLLOID FORM OF PIPERINE. XCVI1.-The colloid fawn of Pipeline, ‘with especial reference to its Refiuctive ccnd Dispersive Powem. By HENRY G. MADAN, M.A. PIPERINE, the alkaloid extracted from pepper by digestion with alcohol, appears to have attracted what little attention has been bestowed upon it rather from its chemical than from its physical properties. Wacken- roder, however (quoted by Gmelin, Handbook of Chemistry, 15, 18 *), observed that the crystallised subs tance, after being melted, solidified G n cooling into a resinous, strongly refracting mass. More recently, this resinous form of piperine has been tried as a material for mount- ing objects for examination under the microscope, but i t has not been found satisfactory, partly from an apparent want of permanency, but mainly because it is found to interfere with the definition of objects immersed in it, The reason of this will be evident from what is said in the latter part of this paper with reference to its dispersive power. It seemed desirable, in the first place, to ascertain the exact conditions under which crystalloid piperine is converted into colloid piperine, and vice versa.For t h i s purpose, some of the ordinary substance, crystal- lisgd in monoclinic prisms, was placed in a beaker, and the latter was placed in an oil-bath maintained a t a temperature of 180’. The crystals melted a t 1 3 2 O , and as soon as the whole was fully liquefied a portion of it mas poured off upon a glass plate and marked ‘‘ A,” The beaker was replaced in the oil-bath and further heated.As soon as its con- tents had reached the temperature of the bath, namely, 180°, they vere poured off upon another glass plate and labelled “ B.” I n both cases, A and B, the substance solidified to a light yellow, transparent resin (the colour of B being rather darker than that of A), without any sign of crystallisation. When cold, the mass was tough and slightly “ tacky,” receiving a faint indentation from the finger- nail. A small portion was detached from specimen A and heated slowly on a water-bath. A t a temperature just below 100’ it quickly * The original paper appeared in Archiv. des Apothekervwein iin niirdlichen Deutsch- Zmzd, von Rnd. Brandes, 37, 349 ; a reference which I have not been able t o verify.MADAN: THE COLLOID FORM OF PIPERINE. 923 lost its transparency, becoming a light yellow, nearly opaque mass resembling sulphur, which under the microscope was seen to consist of a network of interlacing crystals.This, when further heated, under- went no apparent change until the usual melting point, 132O, mas reached, when i t fused in the ordinary may and solidified as before into a transparent resin on cooling, The process of reheating and cooling was repeated more than once, with the same results. A portion detached from specimen B was treated similarly and behaved in a precisely similar way. The remainders of the preparations A and B were set aside under a bell-jar and examined from time to time. In about ten days, yellow, sulphur-like spots began to appear on the surface of A, and a little later in the interior of the mass also.These, when examined under the microscope, were found to consist of tufts of prismatic crystals, forming a very beautiful object in polarived light. They gradually extended, with the ultimate result that in about three months the sur- face was covered, and in about six months the whole mass had reverted to the crystalline condition, With regard to preparation B, the same gradual change took place ; perhaps rather more tardily than in the case of A, but with the same ultimate result, Several similar sets of experiments have been made, which have only served to confirm the above observations. It would appear, therefore, (1) that at a temperature only slightly, if at all, above its melting pDint crystalloid piperine is converted (for the most part, at any rate) into the colloid condition; (2) that the latter condition, when thus prepared, is not permanent, but reverts spontaneously, after the lapse of a moderate time, and quickly when exposed to a temperature of looo, to the crystalloid form.The closely analogous behaviour of sulphur will be at once recalled to mind. It is well known that octahedral sulphur (Ela), when heated to a temperature of 160° or higher, changes into the colloid form known as ‘ I plastic sulphur,” or ‘‘ SY,” and that the latter, although it can be retained as such for a time by rapid cooling, reverts spon- taneously in the course of a few days, and quickly when heated to a temperature a little below the usual melting point, to the original crystalloid form, S,.A further important point bearing on these changes was observed by Frankenheim ( J . p . Chem., 1840, 16, 7), and also by Deville (Ann. Chim. Phys., 1856, [iii], 47, l l l ) , namely, that during the heating of sulphur, a t a certain point (or, perha,ps, more than one point) of temperature a large amount of kinetic energy, supplied in the form of heat, is transferred to the sulphur molecules, in which it is stored up as some form of statical energy essential to the existence of the plastic condition. (In the phraseology of the924 MADAN: THE COLLOID FORM OF PIPERINE. older physicists, “ a large amount of heat becomes latent.”) This energy reappears in a kinetic form (that of heat) when S, changes back into S,. To quote one proof of the latter fact, Deville, experi- menting with a mass of a kilogram or more of sulphur heated t o 200’, and allowed to cool under uniform conditions, found that while the mass cooled from 170’ to 165’ in 50 seconds, and from 140’ to 135’ in 70 seconds, it took no less than 104 seconds to cool from 1 5 5 O to 150°, and 125 seconds to cool from 150’ to 145’, the endothermic supply serving to arrest the fall in temperature due to loss of heat by radiation and convection.Similarly, when a mass oE sulphur was expoaed to a uniform source of heat, the temperature did not rise at a uniform rate, but slackened while the transfer of energy to t h e molecules was taking place. Now, it seemed very probable that something of the same kind might occur in the case of piperine, and that a prolonged continuance of the supply of heat might be necessary to ensure the complete con- version of the crystalloid into the colloid condition.The following experiments were made with the view of ascertaining whether this was the case. Some crystallised piperine was placed in a beaker immersed in an oil-bath maintained a t a constant temperature of 180’. When the liquefied substance had attained the temperature of the bath, a small portion was poured off on to a glass plate, labelled C,” and reserved for comparison. The remainder was maintained a t 180’ for one hour, near the end of which time it became slightly viscous. The colour also darkened to a full yellow (orange in thick layers), probably owing to the separation of a trace of carbon a t the high temperature, since at 200’ a perceptible amount of decomposition takes place.At the expiration of an hour, the whole was poured off and allowed to cool on a plate labelled “D.” When i t was cold, a small piece was broken off and gradually heated on a slip of glass. It did not crystallise at loo’, nor did it undergo any change until the usual melting point (132O) mas reached, when it became viscous, but did not attain sufficient fluidity to be poured out until the temperature reached 1’70’ or nearly so. It was allowed to cool and again heated, and this was repeated three or four times, but not a trace of crystallisation was observed. A portion of the preparation “(2,” when treated in the same may, became crystalline at loo’, like the preparation ‘‘B” already described.The remainders of both preparations, ‘ I C ” and ‘‘ D,” were kept under a bell-jar and examined from time to time. These experiments were made in October, 1898, and in about a fort- night “ C ” was spotted with yellow ; it passed altogether into the crystalline condition in about the usual time-six months. No change whatever mas noticed in preparation “D,” although its surfaceMADAN: THE COLTdOID FORM OF PIPERINE. 925 was scratched to promote crystallisation if possible ; and up to the present time, more than two and a-half Sears since its preparation, it has remained quite unaltered, closely resembling ordinary ‘ I rosin ” (colophony) in appearance, but not quite so brittle. The inference which we seem entitled to draw from the results of the above experiments (and other similar ones, which corroborate them) is, that in order to ensure with even approximate certainty the conversion of crystalloid piperine into colloid piperine, an exposure t o a temperature of not much less than 180’ for a period of not much less than one hour is required.Whether even then the tendency to revert to the crystalline condition is entirely overcome, time alone can show. I may mention that I have made similar experiments with quinidine, and found it to behave in a similar may. It passes, when heated for an hour to 180°, into a permanent (as far as hitherto observed) colloid, having a rather high refractivity (p,, = 1.602). The Refmctive and Dispevsive Powem of P i p e k e . For the purpose of determining these, a hollow prism was made by cementing thin glass plates (selected with parallel surfaces) to the sides of a prism of dense flint glass.The height of the glass plates was rather more than twice that of the prism, so that they formed above the latter a cell of about the same size and having the same angles. This cell was filled with melted piperine, and thus a double prism was obtained, the lower part of dense flint glass and the npper part of piperine, with a refracting angle common to both. This was mounted in a brass frame with levelling screws for adjustment on the table of the spectrometer. In the first place, the refracting angle was determined in the usual way; the mean of several concordant sets of readings giving a= 24°10’10”. Then the angle of minimum deviation (a) for each of t h e principal lines of the spectrum was observed, both for the piperine prism and the glass one below it, and the corresponding indices of re- fraction were calculated by the usual formula, = &$(a + 8)/sin$a.The results are given in the table on p. 926. It will be evident from the figures given i n the table that colloid piperine possesses a higher refractivity than most, perhaps all, other resins or resin-like substances, the only one which comes a t all near it, so far as I know, being naphthyl phenyl ketone (Phil. Mag., 1886, [v], 21, ~245) (for which pD = 1.669) and the compound which it forms with bromine.926 MADAN: THE COLLOID FORM OF PIPERINE. E ............................................. Hg (F) .................................... Hy .......................................... Indices of refraction of piperine and of dense JEint glass.1.710 1.738 1-810 Spectrnm-line. I Piperine. Piperine ..................... 0-142 Phosphorus .................. 0.106 Methylene diiodide ......... 0.062 Phenylthiocarbimide . . , . , . 0-060 -I Carbon disulphide ......... 0.057 a-Monobromonaphthalene 0.05 1 Dense flint glass ......... 0.040 Glass. 1.758 1.766 1.774 1’784 1-795 1.806 Coefficient of dispersion (pHy - p H a ) 0.143 0.040 * For the observation of the hydrogen-lines, one of the “end on” vacuum tubes devised by Prof. Piazzi Smytli was used, in which the light from a considerable thickness of glowing hydrogen is passed through the slit, and a very brilliant spec- trum is obtained. t The only other determination of the refractivity of piperine which I have been able to find is one by Dr.P. Riedel of Jena, quoted in Behrens’ “ Tabellen,” (1st edition); and he only gives one index, namely, ,uD ~ 1 ’ 6 8 4 4 , an agreement sufficiently close to promote confidence in my own results. The above determinations were made with piperine which had not been heated for the full period of an hour. From expcriments very recently made, it would seem that prolonged heating perceptibly dimiuishes the refractivity of the material.MADAN : THE COLLOID FORM OF PIPERINE. 927 hardly appropriate t o enter into details here, but I may say that besides the usual type of nicol prism in which the extraordinary ray is transmitted while the ordinary ray is got rid of by total reflection, there is another class of polarising prisms made of Iceland spar, in which the ordinary ray is transmitted, the extraordinary ray being the one which is turned aside by total reflexion and abolished. For the latter class, of which the prisms devised by Jamin and by Bertrand may be taken as examples, a medium is required which shall have the same refractive index as that of Iceland spar for the ordinary ray, namely, 1.658. Now, although the refractivity of piperine is above this, it can easily be reduced to the proper level by admixture Pipwine. Glass. Caoivarativc lengtl~ of the spectra of piperinc and glass. with Canada balsam. I n fact, I have a prism of this kind in which such a mixture (piperine, 4 parts; balsam, 1 part) replaces the usual balsam film. Unfortunately, however, owing to the ex- t raordinarily high dispersive power of piperine, the critical angles for the different rays of the visual spectrum differ so widely that the prism is practically useless unless monochromatic light is employed. Still, it would be easy to mention other purposes for which a medium of high dispersive power is useful, and it may be of some service to have called attention t'o the eminent degree in which piperine possesses this property.

ISSN:0368-1645    

DOI:10.1039/CT9017900922

出版商:RSC    

年代:1901

数据来源: RSC