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Proceedings of the Chemical Society, Vol. 22, No. 311 |
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Proceedings of the Chemical Society, London,
Volume 22,
Issue 311,
1906,
Page 153-168
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摘要:
.‘ssued 16/6/06 PROCEEDINGS OF THE CHEMICAL .SOCIETY. VOl. 22. No. 311. Thursday, June 7th, 1906, at 8.30 p.m. Professor R. NELDOLA, F.R.S., President, in the Chair. Messrs. E. Feilmann and H. G. Smith were formally admitted Fellows of the Society. Certificates were read for the first time in favour of Messrs. : Robert Anderson, Chester Road West, Sunderland. Reginald William Malyon Gibbs, B.Sc., Hetty Villa, Cam Road, Chesterton, Cambridge. Frederick James Martin, Passagem de Marianna, Minas, Brazil. Herbert Arthur Mills, Waverley, Bloomfield Gardens, Bath. Leonard Edward Beard Pearse, 79, Gordon Road, Esling, W. Thomas Ebenezer Pye, West View, Summersdale, Chichester. Frederick John Salmon, c/o Princess Estate and Gold Mining Co. Ltd., P.O.Box 112, Roodepoort, South Africa. Of the following papers, those marked * were read : “106. (‘Ammonium selenate and the question of isodimorphism in the alkali series.” By Alfred Edwin Howard Tntton. Normal ammonium selenate crystallises differently from the seven rhombic normal sulphates and selenates of the alkalis already investigated, namely, in monoclinic prisms or tttbles, which are described in detail in the paper. A rhombic form of the salt was once obtained (in 1862) by von Lang, but neither Topsije nor the author has been able to reproduce it in pure ammonium selenate. The author has obtained rhombic mixed crystals of ammonium selenate and sulphate, however, and concludes that ammonium selenate is dimorphous, and that the whole series of sulphates and selenates is probably isodimorphous, as has been shown to be the case with other series of the salts of ammonium, potassium, rubidium, and czsium.The original crystals investigated by Prof. von Lang have been kindly sent by him to the author, who finds that the majority are truly rhombic, but that they are somewhat impure, containing admixed sulphate, which is probably the reason for their production, for they closely resemble the author’s mixed crystals, although much richer in selenate. Besides the rhombic crystals, however, some needles were found of nearly pure ammonium selenate, which are identical with the author’s monoclinic form. The monoclinic crystals of ammonium selenate show a pseudo-hexagonal primary prism zone very similar to that of the rhonibic crystals of the other salts, and the topic parameters calculated on this analogous mode of description show a mean value for the structural dimensions intermediate between the mean values for rubidium and czsium selenates.The molecular volume, refractive indices, dimensions of the optical ellipsoid, and the molecylar optical constants are singularly near what mould have been expected if the crystals had been truly isomorphically rhombic, and unite in exhibiting ammonium selenate in its proper position in the series immediately after rubidium selenate, precisely analogous to the position of ammonium sulphate in the sulphate series, and which the author has shown is the general position of ammonium crystlallographically in the alkali series.As a side issue, a general explanation has been arrived at for the beautiful optical property of crossed-axial-plane dispersion of the optic axes, ammonium selenate forming the fifth case of this somewhat Laare phenomenon which has been met with in the alkali series. “107. (‘The vapour pressures of binary mixtures. Part I. The possible types of vapour pressure curves.” By Arthur Marshall. The curves showing the variations of partial pressures with molecular composition may be classified into four types, of which 155 three relate to substances which are miscible in all proportions, and are distinguished one from the other according as pix, the partial pressure divided by the molecular proportion, is less than, equal to, or greater than the vapour pressure of the pure substance.The corresponding total pressure curves are obtained by adding together the two partial pressure curves, which are of the same type. By differentiating the equation of Duhem and Margules, xdlogp, + (1 -x)dlogp, =0,it has been found possible to classify the total pressure curves into twelve types, all of which are known to occur. It may be proved that with pairs OF substances which are miscible in all proportions only one maximum or minimum can occur in the curve of total pressure. The rule, called by Duhem cc Regnault’s Law,” that in the case of partially miscible liquids the total pressure of the heterogeneous mixture is equal to the vapour pressure of the more volatile constituent in the pure state, has been shown experimentally to be approximately true for methyl acetate and water as well as for ether and water, but it is only a rough approximation and is applicable only to some cases.The vapour pressures of the following pairs of liquids have been investigated experimentally : nitroglycerol and acetone, diethylamirie and acetone, ethyl alcohol and methyl ethyl ketone, water and methyl ethyl ketone, water and methyl acetate, water and ether, water and amyl alcohol. From the curve of total vapour pressures, the partial pressures may be obtained by a simple graphical method. *108. The behaviour of acetylene with electrical discharges of high frequency.” By Herbert Jackson and Dudley Northall Laurie. The authors have studied the change, observed by one of them some years ago, when acetylene is subjected to discharges from an ordinary high-frequency apparatus.A semi-solid, brown substance is formed, which sets to a hard and very insoluble solid on exposure to air. If care be taken to avoid secondary reactions by too prolonged a passage of the discharge, the composition of the solid agrees with that of acetylene, and is apparently a polymeride. The substance absorbs oxygen readily up to about 8 per cent. When heated out of contact with air, an oil distils and a small quantity of gas is evolved, which consists mainly of methane and hydrogen. The authors are proceeding with the examination of the reactions oE the substance, which exhibits many curious properties.156 *log. “The behaviour of the vapours of methyl alcohol and acet- aldehyde with electrical discharges of high frequency.” By Herbert Jackson and Dudley Northall Laurie. The authors have examined the reactions as part of a series of ex-periments conducted with a view to determining the nature and order of change effected by high-frequency discharges when passed throngh various gases and vapours. Working with discharges of very short duration, they find the first change in the vapour of methyl alcohol to be the formation of carbon monoxide and hydrogen; in the case of acetaldehyde, the greater part of the vapour breaks up into methane and carbon monoxide, but acetylene and water are also produced simultaneously, though in smaller quantities.Both these changes are reversible, the lgtter more readily than the former. The authors have continued experiments conducted by one of them some time ago on a number of saturated and unsaturated compounds, and they have come to the conclusion that in the case of paraffin derivatives the general tendency is for unsaturated bodies to give polymeric varieties under the influence of high-frequency discharges, whilst saturated compounds, under similar conditions, yield substances of simpler structure. DISCUSSION. In reply to the President : Prof. JACKSONsaid that after trying acetylene made from varying sources, purified acetylene made from calcium carbide and a saturated solution of sodium carbonate was used.The gas was dried over phosphorus pentoxide. No process which could be considered as likely to depolymerise the product gave any acetylene. In reply to Dr. M. 0. Forster : Prof. JACKSONcalled attention to the marked activity of the oxidieed product obtained after exposing the tacky substance freely to air, and stated that the usual methods for examining for activity in the combined oxygen gave no positive result P. 110 . Note on 4-bromo-2-nitro-l(~)-naphthylamine.” By Raphael Meldola and Hugh Gordon Dale. It was shown some years ago by one of the authors and C. H. Desch (Trams.,1892, 61, 765) that the above compound could be diazotised under the usual conditions with the formation of diazonium salts which were stable in the presence of excess of sulphuric acid and in cooled solutions.In repeating the diazotisation of the base for another purpose, the authors have found that if the solution of the diazonium sulphate is diluted with water and warmed, an immediate 157 decomposition takes place with the elimination of the nitro-group and the formation of a diazo-oxide : This compound is therefore isomeric with the diazo-oxide described by one of the authors and F. W. Streatfeild in 1895 (Trans., 67 907), and is identical with the compound more recently described by I(.J. P. Orton (Proc., 1902, 17, 253), with which it agrees in melting point (132O) and other properties. 0.0759 gave 7.3 C.C. moist nitrogen at 11’ and 765 mm.N = 11.46. CloH50N,Brrequires N = 11.25 per cent. The chief point of interest attaching to the present mode of forma- tion of the compound is that it is produced by the elimination of the P-nitro-group, instead of by the displacement of the P-halogen atom, as in Orton’s process. The diazo-oxide on boiling with cuprous chloride solution is con-verted into 1-chloro-4-bromo-2(~)-naphthol,which crystallises from dilute alcohol in white needles melting at 112’ and becoming yellomish- brown on exposure to the air. 0.0851 gave 0.1022 AgCl + AgBr. CloH60C1Br requires 0*1026AgCl + AgBr. Special interest attaches to this chlorobromonaphthol in connection with the replaceability of the second P( = 3)-hydrogen atom, from which point of view the compound may be worth detailed study.Attempts to prepare the 1-chloro-4-bromo-2 :3-naphthaquinone have so far led to negative results, but the experiments will be repeated under different conditions. 111. ‘‘Dinitroanisidines and their products of diazotisation (second communication).” By Raphael Meldola and Frank George C. Stephens. By the nitration of diacetyl-m-aminophenol, the authors have ob-tained a mixture of two isomeric mononitroacetaminophenols, which, on hydrolysis, yield respectively 4-nitro-3-aminophenol (m. p. 185-1 86’) and 6-nitro-3-aminophenol (m. p. 158’). The nitro- acetaminophenols on nitration both yield the same dinitro-derivative, 4 :6-dinitro-3-acetaminophen01(m. p. 168O), and this hydrolyses to 4 : 6-dinitro-3-aminophenol. The latter crystallises in dull orange needles of m.p. 231O. The methyl ether (= 4:6-dinitro-m-anisidine) 158 obtained by direct inethylation, or, more advantageously, by the direct nitration of m-acetaminophenol methyl ether, crystallises in small, canary-yellow needles of m. p. 208” (acetyl derivative, m. p. 146’). This dinitro-m-anisidine does not lose a nitro-or methyl-group on diazotisation, but forms diazonium salts of the ordinary type. From this, combined with former results, the authors concludo that the con- ditions essential for the elimination of a nitro-group on dinzotisation are that there should be w nitro-group, ortho- or para- with respect to the diazonium group, and that this displaceable nitro-group should have a similar group (or possibly a halogen atom) in the ortho-position with respect to itself.Experiments with other dinitro- and haloid- nitroanisidines are in progress. 112. “The action of sulphur dioxide and aluminium chloride on aromatic compounds.” By Samuel Smiles and Robert Le Rossignol. The authors have previously shown (TTCCYLS.,1906,89, 696) that thionyl chloride reacts with phenetole in the presence of aluminium chloride, giving rise successively to a sulphoxide and a sulphonium base ; it has since been found that this reaction may be brought about by sulphur dioxide with the aid of the same condensing agent. An examination of the behaviour of various phenolic ethers towards these reagents has shown that the products of the reaction vary according to the nature and position of the substituents in the aromatic nucleus, and in some cases it has been possible to isolate the primary product, the sulphinic acid, in considerable quantity.Preliminary experiments have indicated that the aromatic hydrocarbons are attacked in a similar manner. 113. ‘‘Action of sodium on aa-dichloropropylene.” By Ida Smedley. Van Romburgh and van Dorssen have shown (PTOC.K. Adad. Vetensch. Anasterclam, 1905, 8,565) that the simplest hexatriene, CH,:CH*CH:CH*CH:CH2, may be eynthesised by heating the diformate of s-divinyl glycol. During the past year, the author has endeavoured to prepare a series of hexatrienes from aa-Gichloropropylene and its homologues. A preliminary account of these experiments is now put forward.Hubner and Genther state that aa-dichloropropylene is indifferent to sodium (Anntden, 1860, 114, 36). The author finds that if a solution of this lvubstance in petroleum (b. p. 100-110”) is heated 159 with potassium or sodium on a water-bath at about SOo during several days and the petroleum solution separated and fractionally distilled, a small amount of a liquid boiling at 60' and a still smaller quantity of a fraction boiling at about SOo can be isolated. A relatively large proportion of a brown, amorphous solid, insoluble in petroleum or water, is also formed in this reaction. The fraction boiling at 60' gave the following results on analysis : C =87.0 ;H = 11.S5. C,H,, requires C =87-81; H = 12-19 per cent.Vapour density found 44,calculated 41. It united readily with bromine, forming a white, soIid tetrabromide melting at 51" and containing S0.02 per cent. of bromine. The liquid was therefore diallyl. The amount of the fraction boiling from 80' to 83' was insufficient for identification; it was probably the hexatriene now isolated by van Romburgh and van Dorssen. The method is being applied for the reduction of aa-dichloro-7-phenylpropylene and of aa-dichloro-y-methylpropylene ; the substances obtained in these experiments are at present under examination. 114. Resolution of lactic acid by morphine."cL By James Colquhoun Irvine. Fermentation lactic acid may be readily resolved into its active components by the crystallisation of the morphine salts.On neutralising an aqueous solution of the inactive acid with the alkaloid, the sparingly soluble morphine I-lactate separated almost quantitatively, whilst the compound with the d-acid remained in solution. The crystalline morphine salt was converted into zinc 2-lactate, which gave [a]y+6*84' and a more accurate test of the purity of the active acid was obtained by its conversion by means of the silver oxide reaction into methylic I-methoxypropionate, which showed [ag' + 94.7O. The latter compound was reduced by hydriodic acid to I-lactic acid, a reaction which shows that silver oxide does not affect the configura- tion of an active lactate. By decomposing the syrup containing the soluble morphine d-lactate, more than 50 per cent. of the theoretical yield of the active zinc salt ([a]; -6.S3') mas obtained. 160 115.('Brazilin and haematoxylin. Part VIII." By William Henry Perkin, jun., and Robert Robinson. The following synthetical experiments have been commenced with the object of obtaining additional evidence as to the constitution of brazilin and hsematoxylin. Po\ a-Hydrindone, C6H;CH; CH,, condenses readily with salicyl-aldehyde in the presence of caustic potash, and is converted into Po\ saZicaZ-a-hydrindone,C,H,*CH,*C:CH*C,H,*OH, which crystallisos in yellow needles and decomposes at 206O. It yields a brilliant red potassium derivative, but does not appear to combine with hydrogen chloride. When methylenedihydrocaffeic acid, CH2:02:C6H3*CH2*CH,*C0,H, is treatod with phosphorus pentachloride and then with aluminium chloride (compare Kipping, Trans.,1894,65, 484),it is converted into C:N*OH /\/\at 160'.The oxime, CH,:O,:C,H,*CH,*CH,, obtained by the action of hydroxylamine hydrochloride and caustic potash in the usual manner, melts at 246O with decomposition. isoNitrosomethylene-Po\ dihydroxy-a-hydrindone, CH,:O,: C,H,* C€€,*C:N*OH, is formed when an alcoholic solution of methylenedihydroxy-a-hydrindone is mixed with isoamyl nitrite and hydrochloric acid. It crystallises in yellow needles, decomposes at 230°, and when treated first with phos-phorus pentachloride and then with caustic potash, yields rrLethyZerne -d~yd~.oxyhomophthaZicacid, CH,:0,:C6H,(C02H)CH,*C0,H, which crystallises from water and melts at about 236'.Benxadmethylenedihydroxy-a-hydrindone,Po\CH,: 0,:C,H,-CH2* C: CH*C,H,, is produced when methylenedihydroxy-a-hydrindoneis treated with benzaldehyde and alcoholic potash, and crystallises in pale yellow needles which decompose at about 250O. Po\ 4:5-Dimethoxy-a-hydrindone(1 :Z), (MeO),C,H,*CH,*CH,, is ob-tained when dimethyldihydrocaff eic acid, (~~eO),-C6H3*CH,-CH,*CO,€€, 161 is treated with phosphorus pentachloride and then with aluminium chloride, It crystallises from benzene, melts at 114O, and, when oxidised with nitric acid, yields tm-hemipinic acid, MeO/\:CO,H NeO()CO,H * Po\ The isonitroso-derivative, (MeO),C,H,* CH,*C:N*OH, crystallises in yellow needles which decompose at about 240”.Po\ XaEicaZdimethoxy-a-hydrindone, (MeO),C,H,*CH,*C: CH*C,H,*OH, is produced when dimethoxy-a-hydrindone is treated, in alcoholic solution, with salicylaldehyde and caustic potash. It crystallises in yellow needles, yields a brick-red hydrochloride, and a brilliant red, crystalline potassium derivative. p-i~~thoxysaZicaldimethox~-a-~yd~~n~one, ,p\ (&i)),C,H2*CH,*C: CH*C,H,( OMe) OH, is of special interest on account of the close relationship which it bears to trimethylbrazilin. It is obtained when dimethoxy-a-hydrindone is treated with p-methoxysalicylaldehyde and caustic potash in alcoholic solution, and crystallises from isoamylic alcohol in prisms which decompose at about 230’.It yields a golden-yellow potassium derivative and a crimson hydrochloride. The authors are engaged in the further investigation of the above and other analogous substances. 116. “A study of the reaction between hydrogen peroxide and potassium persulphate.” By John Albert Newton Friend. It is shown that solutions of hydrogen peroxide and potassium persulphate interact according to the equation H,O, + K,S,O, = 2KHS0, +0,. The reaction, however, is menomolecular. This is due to the formation of an intermediate and highly unstable com- pound, directions for the preparation of which are given. Sulphuric acid is found to exert a retarding influence on the reaction, as do the sulphates of sodium, potassium, and manganese, the last-named accelerating slightly as the reaction nears completion.The action of colloiclal platinum has also been studied. 117. “The action of magnesium methyl iodide on dextro-limonene nitrosochlorides.” By William Augustus Tilden and Frederick George Shepheard. The a-and P-nitrosochlorides were treated separately, but yielded similar products differing only in melting point and degree of optical activity. The compound formed in each case differs in composition from the nitrosochloride by one atom of oxygen, arid therefore has the formula C,oH320N2C1,. It is insoluble in aqueous alkalis and in acids, though easily soluble in the usual organic solvents. Alcoholic potash removes the elements of hydrogen chloride, but the resulting oil rapidly changes in contact with the air.KO definite derivatives could be obtained by the use of any reagent except phosphorus pentachloride, which replaces the remaining atom of oxygen by two atoms of chlorine. The product, C20H,2N2C1,, is optically active and readily loses two molecules of hydrogen chloride, yielding the com-pound C20H,,N2C12,which is also optically active and saturated. The product of the action of phosphorus pentachloride does not react as a nitrogen chloride. 118. (‘Electrolysis of potassium ethyl dipropyl malonate.” By David Cowan Crichton. A concentrated aqueous solution of potassium ethyldipropyl-malonate yields on electrolysis the ethyl esters of a-propyl-p-ethyl-acrylic c~cid,dipropylglycollic mid, tetrapropylsuccinic acid, and pro-bably dipropylacetic acid.The dipropylglycollic acid obtained in the electrolysis was proved to be identical with the ‘‘dipropyloxalic acid ” of Rafalsky. Tetrapropylsuccinic acid yields an anhydride which is characterised by the same stability towards alkalis as tetraethylsuccinic anhydride. 119. ‘*A new method for the measurement of hydrolysis in aqueous solution, based upon the consideration of the motion of ions.” By Robert Beckett Denison and Bertram Dillon Steele. The authors have previously described a method for the direct deter- mination of transport numbers and ionic velocities which necessitates the employment of an auxiliary or indicator solution. This indicator must not be hydrolysed if accurate results are to be obtained, since hydrolysis causes the production of new ions which have an effect on the apparent velocity of the ion which is being subjected to measure-ment. Thus, if lithium chloride is used as an indicator for potassium 163 chloride, correct numbers for the velocity of the K' ion are obtained, since lithium chloride is not hydrolysed in solution.If, however, a salt of the nature of aniline hydrochloride is used as indicator, the H' ions which are produced as the result of hydrolysis cause a false value to be obtained for the velocity of the K' ion. The difference between the real and apparent velocities of the K' ion is dependent on the degree of hydrolysis of the indicator, and it has been found possible, by means of a study of the motion of the different ions in the system, to deduce a formula which gives values for the degree of hydrolysis in the indicator solution well in accordance with the numbers commonly accepted as correct.The only measurements which have to be made are three conductivity determinations. Measurements have been carried out with three salts, namely, the hydrochlorides of aniline, ortho-and pam-toluidine at 18" and 25". The values obtained for the "hydrolysis constants " are : Aniline o-Toluidine p-Toluidine hydrochloride. hydrochloride. hydrochloride. At 18" 61.9 x 103 46.0 x 103 256 x lo3 ,, 25" 43.6 x 103 29.6 x 103 186 103 This gives for the 6' dissociation constants " of the respective bases (assuming for water H' x OH'= 1-2x 10-14) at 25" : Aniline =5.2 x o-Toluidine = 3.5 x p-Toluidine =22 x 10-lo From the values obtained for the '(hydrolysis constants " of the hydrochlorides at 18" and 25", the heat of hydrolysis was calculated by the application of van't Hoff's equation.The results were in fair agreement with the values obtained calorimetrically, the numbers being as follows : Aniline hydrochloride ......... 8700 cals. o-Toluidine ,, .........11000 ,, p-Toluidine ,, ......... 7900 ,, 120. The oxidation of hydrocarbons by ozone at low temperatures." By Julien Drugman. Experimental proof is given that the mode of action of ozone on a saturated and an unsaturated hydrocarbon is very different. Ozone acts, at the ordinary temperature, very slowly on saturated hydrocarbons such as methane and ethane.The process is one of gradual hydroxylation. In the ca5e of ethane, ethyl alcohol is shown to be the first product formed. 164 The reaction in the case of an unsaturated hydrocarbon such as ethylene is instantaneous, even at temperatures far below 0'. A very explosive addition compound is first formed, which decom- poses extremely readily, giving oxidation products containing only one carbon atom. The carbon chain is broken at the double bond. Comparison with the results of Harries' work make it probable that the addition product is an ozonide, but the decomposition of this is more complex than that usually obtained with a liquid or solid ozonide.The f olIowing equations probably represent the process : (a)CH20+ HC0,H(1) CZH, + 0,=C2H403= { (b) CH20+CO + H,O ' (2) C2H403+H20=2CH20+ H202. Formaldehyde, for'mic acid, carbon monoxide, hydrogen peroxide, and water are obtained. 121. '' Reactions involving the addition of hydrogen cyanide to carbon compounds. Part V. Cyanodihgdrocarvone." By Arthur Lapworth. The nitrile formed when carvone unites with one molecular propor- tion of hydrogen cyanide (Ham and Lapworth, Proc., 1904, 20, 54) is cyanodihydrocarvone, cHMe<cH(co-CN) CH2>CH-CMe:CH2, andCH, the two acids to which it gives rise on hydrolysis are the correspond- ing stereoisomeric carboxylic acids. Evidence of the occurrence of reversible dynamic isomerism in the nitrile and the two acids has been obtained. The properties of these compounds and of a number of their deriv- atives are described.122. '' Thiocarbamide as a solvent for gold." By James Moir. Two new complex gold-salts have been obtained by dissolving gold in an acid solution of thiocarbamide (Proc., 1906, 22, 105). They approximate in composition to Au2S04+ 6CH,N2S and AuCl + Z#CH,N,S respectively, but the author considers that the correct formulae are CGH,oN,2S,A~2(S04) and C,H2sN,6SsAu,C13 respectively, + and that both contain a complex cation C2H,N,S2Au [most probably NH:C(NH,)-S(Au)*NH*CS*NH,+]. The author suggests that the I I ___ I abnormal cuprous-t hiocarbamide salts have similar cons titutiou s. The chloride has been studied in some detail.It is converted into the compound described by ReynoIds, C,H,N,S,AuCl, by boiling with 165 hydrochloric acid. Its formation from aurichloride and thiocarbamide takes place according to the equation: 3AuC1, + 8CH4N,S = C,H,,N,,S,Au,Cl, + 6HC1. On warming with sodium hydrate solution, it gives the olive-green gold compound described by B. Rathke (Bey., 1884, 17, 307), which the present author formulates as CH3N2S2Au,; the filtrate contains chloride and sulphide of sodium. On heating to 210’ until constant, the brown residue appears to have the composition Au,S2*3CH4N,S. Silver nitrate gives a mixture of silver chloride, auric hydrate, and silver thiocarbamide in the proportions required by the formula assigned to the original substance.Substituted thiocarbamides have no action on gold. 123. (6 An improved Beckmann apparatus for molecular weight determinations.” By James McConnell Sanders. In the determination of molecular weights by the freezing-point method, employing the Beckmann apparatus as usualiy constructed, several sources of error have to be contended with, some of which depend on the form of the apparatus, and are considerably augmented when hygroscopic solvents such as acetic acid are used. One of the chief difficulties is to equalise the overcooling for parallel observations with the solvent and solution, and it is not always easy to add the ice crystals which induce congelation at correspondingly equal temperature intervals from the freezing point.With the little contrivance (‘‘ Impfstift ”) recommended by Beckmann for this pur- pose, several errors are liable to be introduced; an unknown, or at least a variable, addition to the weight of the solvent is made, the ice crystals absorb moisture during their transference, and during the time that the side tube is open, moisture is absorbed by the solvent in the tube. Moreover, when the temperature of the surrounding atmosphere is but a few degrees above the freezing point of the solvent, it is difficult to ensure the addition of the crystals to the solvent or solution at the precise moment when they are required. Another source of error exists in the introduction of moist atmospheric air by the action of the stirrer. The author has succeeded in eliminating these errors by the use of the modified form of inner tube described in this paper.The principal feature of the new inner tube consists in the use of the narrow, almost capillary side-tube, A, which is fused into the bottom of the solution tube, and is carried up and bent so as to permit the attachment of a thin rubber tube and small bulb, B. When the solvent has been placed in the containing tube, the height of the 166 column of liquid in A can easily be adjusted by first expelling it com-pletely by compression of B, then pinching the rubber tube while B is removed, allowed to fill itself with air, and replaced. On releasing the rubber tube, a small amount of the solvent rises in A, and the height of the column subsequently increases owing to the contraction !, I I I I' ' I1id I II I1 , of the air in the tube produced by the cooling.The container tube is placed in a wide jacket tube (not shown in the figure) in such a way that the side-tube, A, is in contact with the walls of the latter ; a better arrangement is to employ a tube with a lateral canal such as is provided in some hydrometer cylinders. 167 In operation, the column of solvent in A, being nearer to the source of cold, freezes first, and at the moment desired a mass of crystals can be projected into the main body of the solvent by a sharp compression of the bulb, B. The pneumatic stirrer, C, is almost self-explanatory ; it is an adapta- tion of the well-known pneumatic “shutter release,” found on the majority of photographic cameras.The piston and cylinder are of aluminium or glass ground to fit perfectly (in the author’s laboratory use was made of a glass hypodermic syringe of small diameter), the agitator, E,is made by flattening a portion of the length of a piece of platinum wire, and then twisting the flattened portion in the manner shown ; the twisted part is coiled into a spiral form, and the other end of the wire fixed to the end of the plunger or piston. The spripg which balances the weight of the agitator is made of hard drawn aluminium or platino-iridium wire, sufficient, length being given to it to allow of a somewhat extended “ stroke.” One of the conveniences attending this arrangement lies in the fact that both stirrer and ‘(cry stallisation induoer ” can be easily operated without the fatigue attendant on the use of the ordinary form; the operator’s hands rest on the table, and he can conveniently observe the thermometer without his attention being distracted by manipula- tive details.The ordinary side-tube of the Beckmann apparatus is replaced by the small vertical tube, D,which passes through a third perforation in the rubber stopper. The introduction of the substance can be accomplished by the momentary removal of the stopper of D,or if it should be desired to avoid all possibility of the entrance of atmo-spheric air, the substance in the form of a compressed tablet can be previously placed in D and sustained by a bent wire, G, a half revolution of the latter allowing the tablet to drop into the solvent at the desired moment.The apparatus can easily be constructed by anyone accustomed to glass working, or it can be adapted from a small Soxhlet extraction tube by cutting off the upper and lower parts and the wide side tube and bending the narrow syphon tube into the form of A. 168 ADDITIONS TO THE LIBRARY. I. Donations. American Electrochemical Society. Transactions. Vols. IV-VII. Philadelphia 1903-1 905. (Reference). From Dr. F. Mollwo Perkin. Hollard, A., and Bertiaux, 1;. Analyse des mhtaux par electrolyse. pp. xi + 180 + iv. Paris 1906. (Red 28/5/06.) From the Publishers : Messrs. H.Dunod and E. Pinat. Loeb, Jacques. The dynamics of living matter. pp. xi + 233. New York 1906. (Recd. 28/5/06.) From the Publishers : The Macmillan Company. Prantl, Wi’lhelm. Die Literatur des Vanadins, 1804 -1905. pp. 117. Hamburg und Leipzig, 1906. (Red 28/5/06.) From the Publishers : Messrs. Leopold Voss & Co. 11. By Purchase. Blount, Bertram. Practical electro-chemistry. 2nd Edition. pp. xi + 394. ill. London’ 1906. (Recd. 18/5/06.) Leffmann, Henyy, and Beam, JViZZiam. Select methods of food analysis. 2nd Edition. pp. vi + 396. ill. 1905. (Recd. 22/5/06.) CLEVE MEMORIAL LECTURE. The Cleve Xemorial Lecture will be delivered by Professor T. E. Thorpe, C.B., F.R.S., on Thursday, June 21st, 1906, at 8.30 p.m., before the business of the Ordinary Meeting.EXTRA MEETINGS. An extra meeting wili be held on Thursday, July 5th, at 8.30 p.m., and the new Session will begin on Thursday, October 18th. At the next Ordinary Meeting, on Thursday, June 21st, 1906, at 8.30 p.m., the following papers will be communicated, after the delivery of the Cleve Memorial Lecture : “ The constituents of the essential oil from the fruit of Pittosporum undukctum.” By F. B. Power and F. Tutin. ‘‘ Mobility of substituents in derivatives of P-naphthol.” By J. T. Hewitt and H. V. Mitchell. R. CLAY AND SONS, LIMITED, BREAD STREET HILL, E.C., AND EUNGAY, SUFFOLK.
ISSN:0369-8718
DOI:10.1039/PL9062200153
出版商:RSC
年代:1906
数据来源: RSC
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