摘要:

THE QUARTERLY JOURNAL OF THE CHEMICAL SOCIETY OF LONDON. February 19 1849. The President in the Chair. M. Claudet presented a portrait of Dr. M. Faraday taken from a Daguerreotype. Messrs. Edward J. Chapman arid John E. Mayer were elected Members of the Society. The following papers were read IX.-An account of Some experiments with Voltaic Couples. By MR. RICHARDADIE,Liverpool. INcontinuing the experiments submitted last year for the con-sideration of the Chemical Society in which I sought to show that a metallic oxide acted as a negative element to bright portions of the metal from which such oxide was derived I formed a voltaic couple with two similar pieces of zinc one of which was amalgamated while the other possessed a clean-scraped metallic surface.When this couple was connected in the usual manuer with a delicate galvanometer and immersed in oxygenated water I found it easy to obtain the voltaic current at pleasure either from the amalgamated surface as the positive or from the scraped surface as the positive element. The plates were immersed in the water and allowed to remain for some time till the galvanometer in connection with them fell to near zero. The amalgamated plate was then taken out and the surface wiped clean ; on re-immersion the galvanometer immediately indicated that VOL 11.-NO. VI H MR. ADIE ON VOLTAIC COUPLES. the bright amalgamated surface was positive to the other which had remained for some time in the water and was slightly oxidized.Again allowing a space of time for the galvanometer to return near to zero the zinc plate with a scraped surface was removed and again cleaned; when put into the water the galvanometer showed that its surface was positive while the amalgamated surface had now become negative the reverse of what it was in the first trial. These experi- ments were repeated with uniform results the sole condition which regulated the direction of the voltaic current being the state of the surfaces of the pieces of zinc with reference to oxidation Unlcss care was taken however to keep the amalgamated surface untouched I generally found it acting as the positive plate a result to be expected from the circumstance of the amalgamation of the metal rendering the oxide formed on its surface far more easily removeable than the oxide formed on the surface of unamalgamated zinc.From these experiments the object of amalgamating zinc surfaces in voltaic batteries would appear to be to prevent the formation of oxide of zinc on the positive side where it would act as a negative element and waste a portion of the power of the battery in gene- rating local currents. In oxygenated-water batteries the metallic oxides are removed from thc surfaces of the plates by mechanical means only there being no acid present to remove them in the form of soluble salts; but in batteries where acids are used the oxides are removed by combining with part of the acid to form soluble salts. In this case I presume that amalgamating has still the same kind of action which we find exerted in the oxygenated-water battery namely that the particles of the oxidc to be combined with the acid are more feebly attached to the amalgamated metallic surface than to the same surface unamalgamated and are consequently more readily dissolved.The usual explanation given of the advantage resulting from amal- gamated zinc is I believe that it prevents impurities in the zinc from forming local actions but I apprehend that with the purest zinc a coating of oxide on its surface will in an oxygenated-water battery have greater influence in destroying its positive action than any of the metals found associated with common zinc as impurities. In continuing the experiments in which pure specimens of metals were enclosed with distilled water in hermetically sealed glass tubes and where I had found that iron possessed the power at ordinary temperatures of slo~vly decomposing water generating hydrogen I prepared by voltaic action specimens of antimony bismuth lead and tin and placed portions of each of these in test-tubes with pure MR.ADIE OW VOLTAIC COUPLES. water ;the tubes were afterwards hermetically segd the greatest pains having been taken to expel absorbed air from the water by ebullition. In none of these tubes could I discover the slightest evidence of the decomposition of the water. The tubes were then removed to a sand-bath where they were maintained for two months at a temperature of loooFahrenheit above the ordinary temperatures of the weather without any of them showing an increase of internal pressure through the generation of hydrogen.The first three of these metals are held by chemists to be in- capable of decomposing water at any temperature hence it was not to be expected that like iron they should possess a slow power of' decom-posing water ;but having found that when they were formed into the positive elements of voltaic couples excited by water in a rapid state of ebullition the attached galvanometer always indicated a decided action I felt desirous to try carefully whether the effect could be due to a decomposition of the water. As no evidence of this kind could be obtained from theseexperiments it appeared to me that the action of such voltaic arrangements must be explained on the prin- ciple that water boiling in the atmosphere always contains some portion of absorbed air and that it is the oxygen of this air which excites the couple.A plate of copper associated with one of platinum and attached to a delicate galvanometer gave a perceptible action when excited by boiling water when the plates were at the surface the action was greatest; but when these were placed beneath the surface of the water there was still decided action. At a depth of 8 inches below the surface a voltaic current was generated which according to the above view of the action of such a couple could only arise from a portion of atmospheric air reaching the plate.

ISSN:1743-6893    

DOI:10.1039/QJ8500200097

出版商:RSC    

年代:1850

数据来源: RSC

摘要:

99 MIL. ADIE OW VOLTAIC COUPLES. X.-On the Quantitative Separation of Magnesia and of the oxides of Nickel Cobalt and Zinc,from Potash and Soda. By HENI~Y WATTS,%.A. F.C.S. Assistant in the Birkbeck Laboratory UrLiversity College London. The separation of magnesia from the fixed alkalis is well known to be attended with considerable difficulty. The method given in Rose’s Analytical Chemistry,* consists in converting the mixed salts * Dr. Normandy’s Tran&tion vol. IT. p. 43. H2 100 MR. HENRY WATTS ON into sulphates adding acetate of baryta in excess to remove the sulphuric acid filtering ; converting the acetates of baryta magnesia and the alkalis in the filtrate into carbonates by ignition-then digesting in water and filtering again to separate the alkaline carbonates from the insoluble carbonates of baryta and magnesia The magnesia and baryta are then separated by means of sulphuric acid.This method is very troublesome and complicated; and after all does not give very accurate results. An easier method is to make use of baryta-water which preci- pitates magnesia leaving the alkalis in solution and then to remove the excess of baryta either by sulphuric acid or by carbonate of ammonia. This method is unobjectionable when only the alkalis are to be quantitatively determined; but if the quantity of magnesia is likewise to be estimated a great deal of trouble is occasioned by the formation of carbonate of baryta which always takes place more or less during the filtration and washing whatever pains we may take to exclude the air.The magnesia and baryta have then to be separated by sulphuric acid; and this involves the necessity of expelling a considerable excess of sulphuric acid by heat which is a troublesome process. To obviate these difficulties I have devised the following process which is nothing more than a particular application of a method in very general use. It consists in precipitating the magnesia by a known weight of carbonate of soda using a considerable excess ;then boiling and filtering; treating the filtrate with a slight excess of acid; evaporating to dryness and igniting the residue to render it neutral ; weighing the neutral salt thus obtained; and making the proper correction for the quantity of soda-salt introduced.The mode of conducting the process will be best understood by the following examples Twenty-five grains of sulphate of magnesia and potash in well- defined crystals were dissolved in water and the liquid was mixed with solution of 10 grains of perfectly anhydrous carbonate of soda. The mixture which was strongly alkaline was then boiled for half-an- hour the water being renewed as it evaporated. This continued boiling is essential to the complete separation of the magnesia. The carbonate of magnesia was collected on a filter washed with boiling water then dried and ignited. The quantity of magnesia thus obtained was 2.555 grains; by calculation it should be 2.557. The filtrate which contained sulphate of potash sulphate of soda and excess of carbonate of soda was then slightly acidulated with sulphuric acid to convert the carbonate into sulphate so that THE SEPARATION OF MAGNESIA FROM THE ALKALIS.101 sukhuric acid should be the only acidpresent. The liquid was lastly evaporated to dryness in a porcelain crucible and the residue strongly ignited to render the sulphates neutral; carbonate of ammonia being added to remove the last portions of the excess of acid. The residue gave Sulphate of potash + sulphate of soda = 24.015 gr. Now it must be remembered that 10 grains of dry carbonate of soda were introduced at the beginning of the process; and 10 grains of carbonate yield 13-4 grains of anhydrous sulphate. Deducting this from the weight of the mixed sulphates we have 10.615 grains of sulphate of potash which corresponds to 5.73 of potash.The calculated quantity is 5.84. In a second experiment conducted in the same manner the quantity of magnesia was 2.56 and that of potash 5.77. The following table contains the results of the two experiments calculated to 100 parts and likewise the mean of the two. The fourth colizmn gives the theoretical quantities according to the formula KO SO + MgO SO + 6 HO; and the last coluinn gives the differences between the third and fourth. The quantities of sulphuric acid and water of crystallization were likewise deter- mined by the usual methods in order to prove that the salt was of definite constitution I. 11. Mean. Calculation. Difference. Magnesia .10.24 10-22 10.23 10.23 0.00 Potash . . 23.08 22.92 23-00 23.36 0.36-Sdphuric acid 39.40 39-76 39-58 39.68 0.10-Water . . 26.96 26.92 26-94 26-73 0.21+ 99.68 99.82 99.75 100.00 It will be seen from this that the process is capable of affording very good results. To ensure accuracy however it is absolutely necessary that the solution after the carbonate of soda has been added to it be well boiled for at least half-an-hour. The object of this continued boiling is to decompose a difficultly soluble double carbonate of soda and magnesia which is formed on the first addition of the alkaline carbonate.* The carbonate of soda must likewise be added in considerable excess ; otherwise the precipitation will not be complete. The precipitate of carbonate of magnesia must be washed * Vide Rose Normandy’s Translation II.35. MR. HENRY WATTS ON with boiling water and the washing not too long continued; for the carbonate is not completely insoluble. The washing should be dis- continued as soon as the wash-water ceases to give a distinct alkaline re-action; when this takes place the water begins to dissolve the carbonate of magnesia. When as in the above examples the quantity of magnesia can be approximately estimated beforehand it is easy to calculate the quantity of carbonate of soda required to precipitate it ;considerably more than that quantity should however be used. But if no such estimate can be formed-and this will generally be the case-a certain quantity of the carbonate of soda may be weighed out and then added in small portions at a time till the liquid becomes strongly alkaline.The residue may then be weighed and the difference of the two weighings will give the quantity used for the precipitation When a quick approximation is desired rather than a very accurate result a solution of known strength may be used and the quantity determined by a graduated measure. But where great accuracy is an object the method of weighing is much to be preferred. Great care should of course be taken that the carbonate of soda is absolutely pure and anhydrous. The best mode of preparing it is to ignite the bicarbonate or sesquicarbonate. In the above examples the magnesia and alkali were in the form of sulphates. If they are in the form of chlorides the determination of the alkali will be easier; because the excess of hydrochloric acid is more easily driven off than that of sulphuric acid.If they are in the form of nitrates or if two or more acids are present it is best after separating the magnesia to add sufficient sulphuric acid to convert the whole into sulphates. When both potash and soda are present the best plan will be after precipitating the magnesia to convert the alkalis into chlorides which may always be done; then determine the total weight of the alkaline chlorides ;deduct the weight of chloride of sodium equivalent to the carbonate of soda used; and lastly estimate the quantity of chloride of potassium in the usual manner by precipitation with bichloride of platinum.The same method is applicable to the separation of nickel cobalt and zinc from the fixed alkalis. The usual mode of effecting this separation is by means of sulphide of ammonium. But this method though practicable is attended with very great difficulties; for the sulphides of these metals arc to a certain extent soluble in excess of sulphidc of ammonium; and if an excess of this reagent be not used THE SEPARATION OF MAGNESIA FROM THE ALKALIS. 103 and the precipitate not washed with water containing it the precipi- tate oxidizes and is converted into a soluble sulphate which runs through the filter. The following examples will show that the method of precipitation with a known weight of carbonate of soda gives results as accurate as those obtained with the magnesia-salt.I omit the details of the process as they are exactly similar to those above described. The quantities of sulphuric acid and water are likewise given for the same reason as in the former case. Sulphate of zinc and potash ZnO SO + KO SO + 6 HO Exp. Calculation. Difference. Oxide of zinc . . 18.08 18.44 0.36-Potash . . 21-08 21.22 0.14-Sulphuric acid. . 35.88 36.06 0.18-Water . . 2473 24.28 0°43+ 99.77 100*00 Sulphate of nickel and potash Ni 0 SO + KO SO + 6 HO Exp. Calculation. Difference. Protoxide of nickel . 17-12 17-16 0.04-Potash . . 21-52 21.55 0.03-Sulphuric acid. . 36.35 36.62 0.27-Water. . . 24.96 24.67 0.29+ 99-95 10*OOQ The same precautions are necessary as in the case of magnesia viz to use a considerable excess of carbonate of soda boil for a long time wash with boiling water and not too long.The examples above given are sufficient to illustrate the method. I have caused it to be tried in a great number of instances by pupils working under my direction in the laboratory of University College. The results are always satisfactory when due attention is paid to the precautions above specified. I now lay it before the Chemical Society in the hope that it may contribute something towards the removal of an acknowledged difficulty in analysis

ISSN:1743-6893    

DOI:10.1039/QJ8500200099

出版商:RSC    

年代:1850

数据来源: RSC

摘要:

DR. HOFMANN ON XI.-On the Composition of Mesitdole and some of its deyivutiues. By DR. A. W. HOFMANN. We a.re indebted to Sir Robert Kane for the investigation of an interesting class of compounds arising from the decomposition of acetone.* The general result of these researches was the exhibition of a remarkable analogy in the nature of this body to that of an alcohol. The original formula for acetone as resulting from Dumas’ and Liebig’s analyses was representing an equivalent of an acetate minus an equivalent of a carbonate ; a formula which subsequently when Dumas determined the density of the vapour of this liquid was doubled on the supposi- tion that its equivalent corresponded to 4 volumes of vapour. The products of decomposition of acetone afforded an additional support to the formula as representing the equivalent of this body which according to the experiments of Kane we 6ave to consider as the hydrated oxide of a compound radical mesityl analogous to methyl ethyl and amyl HO C H 0.In fact Sir Robert Kane succeeded in isolating the oxide of this radical as also in combining it with sulphuric and phosphoric acids and in preparing the chloride and iodide(?) corresponding to the oxide. He moreover obtained a liquid hydrocarbon which he described under the name of mesitilene (mesitilole) and which he considered as repre- senting in his new series the olefiant gas of common alcohol. So far the analogy is complete; we may add even that since that period an acid has been discovered which in the mesityl-series would correspond to the acid terms of the other alcohols.We know that all true alcohols by losing two equivalents of hydrogen and assuming two equivalents of oxygen pass into a class of acids of which formic acetic and valerianic acids are familiar instances. Now acrylic acid (acronic acid Berz.) which Prof. Redtenbacher discovered among the derivatives of glycerin stands to acetone exactly in the relation which exists between common alcohol and acetic acid. C Hfj 0,-H + 0,= C H 0, -+ w Alcohol. Acetic acid. * “On a series of combinations derived from Pyroacetic Spirit,” Dublin 1838. THE COMPOSITION OP MESTTILOLE. Acetone. Acrylic acid. Acrylic acid has not yet been prepared from acetone which when subjected to oxidizing agents is converted into acetic and formic acids; but if we consider the great facility with which according to Redtenbacher’s experiments acrylic acid is itself converted into these two acids we may still perhaps hope to arrive at this result by a judicious selection of the proper oxidizing agent.These observations sufficiently prove that acetone exhibits in a remarkable manner the characters of an alcohol ; nevertheless our views respecting the nature of this compound appear to be by no means settled. Indeed the progress of science has not failed to raise a series of objections to the opinion which at the time of Sir Robert Kane’s experiments appeared most probable. The extreme instability of the mesityl compounds at once distin- guishes this group of bodies from the derivatives of the regular alcohols from which it differs moreover in the ratio of the carbon and hydrogen equivalents.The impossibility of reproducing acetone from these derivatives and the difference in the constitution of sulphomesitylic and sulphovinic acids likewise appeared to discoun- tenance the reception of acetone into the group of well-established alcohols. The former of these objections has lost some of its weight since in the cyanides of the alcohol-radicals we have become acquainted with a class of alcohol-compounds likewise irreconvertible into the original terms whilst the latter might perhaps be removed by a closer investigation of sulphomesitilic acid and its compounds. Be this however as it may the state of our knowledge respecting the derivatives of acetone clearly proves that this field has not yet been sufficiently explored.The following pages contain a small contribution to the history of mesitilole one of the most interesting among the acetone-descendants which the researches of Sir Robert Kane have elicited. To trace the analogy of acetone and alcohol this chemist naturally directed his attention to the action of dehydrating agents on the former. He found that sulphuric acid readily decomposed acetone giving rise to a variety of products among which an oxigenated liquid oxide of mesityl according to Kane the ether of the series and an oily carbohydrogen (mesitilene) the representative of olefiant gas are enumerated.I have repeated this reaction with preciscly the same results. On distilling a mixture of 2 volumes of acetone and 1 volume of con- DR HOFMANN ON centrated sulphuric acid a distillate is obtained consisting of an aqueous solution of sulphurous acid on the surface of which an oily liquid floats whilst a dark-brown residue remains in the retort. Kedistillation of this liquid after washing with water and drying evinced at once the compound nature of the oil which commenced to boil at about looo C. (212O F.) the boiling-point rising gradually to upwards of 250° C. (482OF.) My attent,ion being chiefly directed to the carbo-hydrogen which according to Kane boils at 135O C. (275O F.) I collected the distillate passing over between 120° C. (248O F.) and 160° C.(320O F.) separately. On repeatedly dis- tilling this quantity I however soon found that the boiling tempe- rature of the substance I was in search of was much higher than 135O C. (275O F.) ; I was consequently obliged to fraction the whole portion passing over in the first distillation between 120°C. (248OF.) and 200° C. (392OF.) After very numerous distillations a liquid was obtained boiling pretty constantly between 155O C. (311° F.) and 160° C. (3.20° F.) which possessed all the properties Sir Robert Kane attributed to his substance excepting the boiling-point to the difference in which I have alluded above. The analysis of mesitilole originally led to the ratio of carbon and hydrogen equivalents- but both the formation of the new body as being derived from acetone and the products into which it is converted under the influence of various agents proved at once that the equivalent of mesitilole was higher.In fact the preparation of a beautiful crystal- line body by the action of chlorine upon mesitilole and described by Kane under the name of chloride of pteleyl compelled him to double the above formula into the following expressions Mesitilole . . . . . C6 H* Chloride of Pteleyl . . Cs( ti} a change which rendered the transformation of acetone perfectly ana-logous to that of alcohol under the same circumstances C H 0,+2H SO,=C H,+2(H SO HO) + + Alcohol. Olefiant gas. C H6 O,+ZH SO,=Cs H,+2(H SO HO). -U Acetone. MesitiloIe. THE COMPOSITION OF MESITILOLE.This formula for mesitilole appeared to be confirmed by the com-position of the corresponding bromine- and nitro-compounds Bromine-compound . . Cs{t } Nitro-compound . . . . C,(Eb4 I-which at a later period were discovered by M. Cahours. The determi- nations however of the density of the vapour of mesitilole in which M. Cahours had hoped to obtain further support for this formula gave results which induced many chemists to double again the formula of mesitilole. According to Cahours’ density one equivalent of this substance would contain only two volumes of vapour whilst all other hydrocarbons whose equivalents have been ascertained by metamor- phoses have been found to correspond to four volumes of vapour. In fact we know as yet no exception to this general rule.Olefiant gas Faraday’s gas Amilole Cetole Benzole Toluole Naphthalole &c. substances the equivalents of which we may consider as fixed both by their origin and by their descendants all contain invariably four volumes of vapour in one equivalent. These considerations have pretty generally led to the adoption of the following formuh for the mesitilole series Mesitilole . . . . . . C, H :{ C12{ Bromine-compound. . . C12{ zi } Nitro-compound . . . C1,{fio4} All the observations which we possess respecting $his group appear to find a satisfactory explanation in the assumption of the above formula there is only one property of mesitilole which does not well agree with this expression viz. its boiling-point.In the present state of our knowledge respecting the boiling temperatures of liquids the discrepancy of the actual boiling-point of mesitilole and the tem- perature at which we should expect the ebullition of a liquid repre- sented by the formula could not fail to throw some suspicion on the exactness of this ex-pression If we recollect that the accurate experiments both of Chlorine-compound . . . } 108 DR. HOPMANN ON Mr. Mansfield* and Dr. Kopp,? have fixed the boiling-point of benzole at 80' C (17'6' F.) we cannot but be surprised to find a liquid of very similar constitution containing thc same number of equivalents of carbon and even more hydrogen boiling at SO much higher a temperature. An increase in hydrogen almost invariably depressing the point of ebullition of a cornpound we should expect to see mesitilole boiling rather at a lower than at a higher temperature.This circumstance has not escaped Leopold Gmelin who in his Handbook$ alludes to this discrepancy. He attributes however to the presence of substances possessing a higher boiling-point in the crude product after the action of sulphuric acid upon acetone that the boiling-point of Kane 135O C. (2750 F.) had been observed too high. He mentions likewise that the boiling-point would correspond more closely with a substance of the formula c, %-We shall see directly that this formula actually represents the corn- position of mesitilole. The purification of mesitilole is attended with considerable diffi- culty and although working on rather a large scale I have not been able to obtain a perfectly fixed temperature for this substance; but numerous experiments made both by Ah.Maule and myself have proved that this point is decidedly between 155O C. (3110 F.) and 160° C. (320' F.) This boiling-point of rnesitilole higher even than had resulted from Kane's experiments could not fail to invite me to a few experiments with this body in order to obtain further data for establishing its composition. It appeared by no means impossible that by the moderate action of decomposing agents substances might be pro- duced differing in composition from those hitherto obtained and thus afford a key for the solution of the question. Action of Bromine on Mesitilok-The inferior affinity for hydrogen which distinguishes bromine from chlorine naturally directed my attention first to this powerful salt-former.Bromine was added carefully drop by drop to mesitilole waiting each time until the heat evolved had subsided and taking care to keep the hydrocarbon in excess. Mesitilole is thus converted into a white crystalline compound which was freed from hydrobromic acid by washing with water in which it is perfectly insoluble. Two or three crystallizations from boiling alcohol render this compound absolutely pure. It presents * Journ. of the Chem. SOC.Vol. I. 244. f Pogg. Ann. Bd. LXXII. 1 and 223. $ Vol. IV. THE COMPOSITION OF MESITILOLE. itself in white needles which are volatile without decomposition and are not changed by ebullition with either potash or ammonia.Analysis gave the following results I. 0-3595 grm. of bromine-compound gave 0.4048 , , carbonic acid and 0.0905 , , water. 11. 0.0223 , , bromine-compound gave 0.3540 , , bromide of silver. Per-centage composition Carbon . . I. 30.70 11. - Hydrogen . 2.79 - Bromine . - 66.68 These numbers lead exactly to the composition of M. Cahours' bromine-compound corresponding with either Theory. Experiment. -12 equiv. of Carbon . . . 72.00 30.70 30'70 6 , , Hydrogen . . . 6-00 2-56 2.79 2 , , Bromine . . . 78.86 66.74 66.68 1 equiv. of Bromine-compound 156.26 100.00 1OO.l'd The properties of the substances likewise prove their identity. Action of Nitric Acid on MesitiZoZe.-The action of this acid on the carbohydrogen has been likewise studied by M.Cahours. On treating mesitilole with concentrated nitric acid he found that a dark yellow oil was produced which did not present a sufficiently definite character for analysis ; by employing however a mixture of concen- trated nitric and sulphuric acids he obtained a beautiful crystalline compound which when purified by washing with water and repeated crystallizations from alcohol or by sublimation exhibited the lustre of metallic silver in a remarkable degree. Analysis proved this com- pound to be either DR. HOPMANN ON My experiments have led me to the same result. By acting either with the sulphuro-nitric mixture or with fuming acid alone I have obtained this compound with all the properties which If.Cahours has assigned to it. To his description I need only add that this substance dissolves with extreme difficulty in boiling alcohol and ether but is easily purified by crystallization from acetone in which as Mr. Made has found it readily dissolves. The following numbers were obtained on analysis 0.2210 grm. of substance gave 0.3415 , , carbonic acid and 0.0770 , , water. The per-centage obtained from these numbers closely corresponds with the formula as exhibited in the followiiig table -Theory. Experiment. 12 equiv . of Carbon . . . 72 42-35 42.14 6 , , Hydrogen . . 6 3.53 3-87 2 , , Nitrogen . . 28 16.48 - 8 , , Oxygen. . . 32 37.64 - 1 equiv. of Nitro-compound 138 100.00 So far my endeavours were attended with but little success.By employing nitric acid of inferior strength however I obtained at once a different result. Mesitilole when boiled with dilute nitric acid is very gradually attacked it turns yellow and loses part of its fluidity. After repeated distillations it is converted into a yellow oil showing a tendency to crystallize. This oil is evidently a mixture and I have not been able to effect a separation too small a quantity of mesitilole being at my command. By substituting nitric acid of moderate concentration however for the dilute acid a few distillations were sufficient to convert the whole of the mesitilole into the crystalline compound which presents itself in very fine needles sometinies several inches in length.These crystals were washed with water and finalIy recrystallized from alcohol the facility with which they dissolve in this liquid directly showed mc that I bad a substance in hand perfectly THE COMPOSITION OF MESITILOLE. different from the previous nitro-compound which it resembles in many other respects especially in its outward appearance and its volatility without decomposition. Analysis gave the following results I. 0.2915 grm. of substance gave 0.5445 , , carbonic acid and 0.1310 , , water. 11. 0.2050 , , substance gave 0.3840 , , carbonic acid and 0.0915 , , water. 111. 0*2280 , , substance gave 0.4280 , , carbonic acid and 0*1030 , , water. Per-centage composition I.11. 111. Carbon. . . . . 50.94 51-08 51.15 Hydrogen . . . . 4.95 495 5.01 These numbers closely correspond with the formula c H N 04 which has to be doubled into the expression c Hf3 not being reconcileable with the formulx for the other derivatives of mesitilole. Theory. Experiment. -18 equiv. of Carbon . . . 108 51.42 51.07 10 , , Hydrogen . . 10 4-76 4.98 2 , , Nitrogen . . 28 13.35 -8 , , Oxygen . . . 64 30-47 -1 , , Nitro-compound --2lo* 100~00 Its subsequent transformation into nitromesidine by Mr. Maule altogether precluded the necessity of determining the nitrogen in this compound. The existence of a body of this nature can leave no doubt respect- ing the true formula for mesitilole. It is evident that a compound of 112 DR.HOFMANN ON the indicated composition can be derived only from a carbo-hydrogen of the formula Cl H12 which I consider as the true expression for the equivalent of mesitilole. The formula of mesitilole becomes thus identical with that of another carbo-hydrogen which is found among the derivatives of cuminic acid viz. with cumole. These substances are however far from being actually identical. It is only necessary to compare the odour of the two liquids and their comportment with reagents in order to remove every doubt upon this head; still these substances as might be expected exhibit a remarkable analogy in their physical properties their boiling points being indeed so near each other that I do not despair of finding that they are actually identical.The boiling point of mesitilole is as I mentioned probably bctween 155O C. (311O F.)and 160"C. (320O F.) ; for the boilingtemperature of ciimole we possess three different observations respectively an-nouncing it to be at l44Y C. (291O F. Gerhardt and Cahours*) 143OC. (299O F. Abelt) and 153°C. (308O F. Gerhardtt.) It is not impossible that these two liquids boil actually at the same temperature. The compounds too arising from the reaction of nitric acid upon cumole present a certain analogy although here likewise we meet with discrepancies. We have become acquainted with nitrocumole and dinitrocumole but a trinitro-compound corresponding to trinitromesitilole for such the nitro-compound first described must henceforth be considered has not been formed although 11.Cahoura subjected both hydro-carbons to exactly the same treatment. In adopting the new formula for mesitilole we interfere as is easily seen in no way with the former results all the analyses are perfectly correct they have to be interpreted only in a different manner. There is however one observation which at least according to principles generally admitted is no longer reconcileable with the atomic com- position of our conipound. This is the determination of the density of mesitilole as made by M. Cahours. If this determination be correct -and we have scarcely a better authority in experiments of this kind than M. Cahours,-one equivalent of mcsitilole would represent not less than 6 volumes of vapour a number which has bcen never observed in any similar case.All the well investigated hydro-carbons have * Ann. de Chim. et de Phys. 3me Skrie I. p. 60. t Memoirs of Chem. SOC. Vol. III. p. 144. $ Ann. de Chini. et de Phys. 3me SCrie Toni XIV. 111. THE COMPOSITION OF MESITILOLE. given hitherto invariably 4 volumes. It is possible that the specific gravity of the mesitilole vapour is subject to similar variations as have been observed with acetic butyric valerianic acids and several other compounds; it is possible likewise that an equivalent of mesitilole is actually represented by 6 volumes of vapour and this anomalous condensation may assist in explaining the difference between the constitution of this body and cumole which like the other hydrocarbons contains only 4 volumes of vapour.Be this however as it may the subject requires further investigation. have hitherto been prevented repeating the determination of the specific gravity from not having obtained the hydrocarbon of a perfectly constant boiling-point. The discrepancies existing between the theoretical and experimental density of mesitilole when expressed by the formula compelled me to search for additional support for this formula from other facts. The action of sulphuric acid promised to afford some valuable results with reference to this question. Action of fuming su@hriC acid on mesitilole.-Mesitilo-su~~u~c acid.-Common concentrated sulphuric acid acts but very slowly upon mesitilole ;fuming acid dissolves it more readily a reddish brown liquid being produced which when exposed to a moist atmosphere becomes gradually crystalline.The application of heat must be avoided as it carbonizes the compound with the evolution of sul-phurous acid. The evolution of a small quantity of this gas cannot be prevented even when operating in the cold. On diluting with water the brown liquid becomes colourless and yields when saturated with an excess of carbonate of lead a soluble lead-compound insoluble sulphate of lead remaining. The lead- salt is extremely soluble both in water and alcohol which renders it difficult of purification. However by treatment with animal char- coal and subsequent gradual evaporation it may be obtained in beautiful white needles of perfect purity; the analysis of this com- pound gave the following results I.0.3180 grm. of lead-salt gave 0.1580 , , sulphate of lead. 11. 0.2853 , , lead-salt gave 0.1426 , , sulphate of lead. VOL. 11.-NO. VI. I 114 1)R. HOFMANN ON 111. 0.3043 , , lead-salt gave 0.3979 , , carbonic acid and 0.1045 , , water. Per-centage composition I. 11. 111. Lead . . . . . 33.95 34.15 -Carbon . . . . -35.66 I Hydrogen . . . -3-81 These numbers lead exactly to the formula as exhibited in the following table Theory. Experiment. * 1 eqdiv. of Lead . . . . . . 103.56 34.22 34.05 18 , , Carbon . . . . . 108*00 35.69 35.66 11 , , Hydrogen . . . . 11.00 3-63 3.81 2 , , Sulphur . . . 32.00 10.58 -6 , , Oxygen .. . . . 48.00 15.88 -1 eq. of Mesitilosulphate of lead 302.66 100.00 The analysis of this lead-salt proves that the action of sulphuric acid on mesitilole gives rise to a new acid perfectly analogous to hyposulphobenzolic and hyposulpbocumolic acids with the latter of which our new compound is identical in composition. The object of these experiments being only to obtain a further confirmation of the new formula of mesitilole I have not studied the salts of this acid any further. I may mention however that it forms a crystallizable silver salt which is likewise extremely soluble in water and readily blackens when exposed to the light. The formula which I propose for mesitilol arid which receives further confirma- tion in the study of nitromesidine a beautiful alkaloid discovered by Mr.Maule removes this compound to a certain extent from the position originally assigned to it by Kane. We can no longer consider it as the representative of olefiant gas in the mesityl-series it would much rather correspond to those liquid hydrocarbons which we invariably meet with in the dehydration of both vinic and amylic '18 THE COhiPOSITION OF BIESITILOLE. alcohols and which up to the present moment have not been suffi-ciently investigated scarcely anything beyond their isomerism with olefiant gas being established. I cannot omit here pointing out that in mesitilole we have another instance of the remarkable tendency exhibited in certain molecular systems of uniting three atoms of an inferior order into one com- pound atom of a higher position.Similar examples we possess in the interesting transition of cyanic acid into cyanuric in the solidification of chloride of cyanogen gas and in the transformation of cyanide of ethyl into kyanethine. The natural product too which we should expect from the dehydration of acetone isa substance of the formula and it is not improbable that this compound is actually formed at a certain stage of the process; under the influence however of the powerful agent in the presence of which it is generated we find it rapidly converted into a compound containing the triple number of equivalents. Finally the correction of the formula for mesitilole affords a striking illustration of the valuable assistance which chemical studies are likely to derive from a more minute investigation of boiling tem- peratures.The following table exhibits a synopsis of the mesitilole series Mesitilole .........Cl HI Trichloromesitilole ...... C, H {cc } Tribromomesitilole ...... Nitromesitilole ....... HI * Dinitromesitilole ....... '18 (2N0,) Trinitromesitilole ...... {3%,} Mesitilosulphuric acid ...H SO C, {f&2 } Nitromesidine .......

ISSN:1743-6893    

DOI:10.1039/QJ8500200104

出版商:RSC    

年代:1850

数据来源: RSC

摘要:

MR. MAULE ON NITR,OMESIDINE. XII.-On Nitromesidine a new Organic base. By GEORGEMAULE ESQ. STUDENT OF THE ROYAL COLLEGE OF CHEMISTRY. The new researches upon the composition of mesitilole pointing out as they do the remarkable isomerism of this substance with cumole the carbo-hydrogen of the cuminic acid series made it desirable to study some further derivatives of this body in order to obtain additional evidence in favour of the new formula. No investigation appeared more appropriate for such a purpose than that of the comportment exhibited by its nitro-compounds with reducing agents. The formation of new alkaloids corresponding to the nitro-compounds of mesitilole which was to be expected and the simple and accurate methods which we possess of determining the equivalents of such bodies promised to furnish a series of facts par- ticularly calculated to control the exactness of the corrected formula.Cumole when treated with nitric acid gives rise to nitrocumole and dinitrocurnole two substances which have been converted into basic compounds by the action of hydrosulphuric acid. The former com-pound is converted into cumidine investigated by Mr. Nicholson whilst the latter yielded to M. Cahours the substance described by him a short time ago under the name of nitrocumidine. The existence in the mesitilole series of a body isomeric with nitrocumole being still doubtful Dr. Hofmann invited me to try the production of a base corresponding in composition to nitrocumidine. The following payer contains a description of this new body which is actually produced without difficulty and for which I pro-pose the name Nitromesidine instead of Nitromesitilidine which would be the term for it constructed according to analogy.On submitting an alcoholic solution of dinitrocumole to the action of hydrosulphuric acid the liquid assumes a dark colour and deposits gradually a large quantity of sulpbur whilst the odour of the hydrosulphuric acid disappears. This treatment is continued for several days until a fresh quantity of hydrosulphuric acid is no longer decomposed. On the addition of hydrochloric acid sulphur is again precipitated which is separated by filtration when a clear liquid is obtained which yields a copious yellow deposit when MR-MAULE ON NITROMESIDINE.117 mixed with a solution of potash or ammonia. This precipitate is nitromesidine in an impure state. To purify this substance it is repeatedly dissolved in hydrochloric acid and reprecipitated by an alkali. In this manner small quan- tities of still-adhering sulphur are separated and the substance gradually assumes a bright yellow colour. One or two crystalliza-tions from alcohol now suffice to render it absolutely pure. Composition of Nitrumesidine.-The following analyses were made on crystallized specimens of pure nitromesidine prepared at different periods and dried at 1000 C. (212O F.) I. 0.2861 grm. of substance gave 0.6309 , ,,carbonic acid and 0.1716 , ,,water. 11. 0.2072 , , substance gave 0.4561 , , carbonic acid and 0.1264 , , water.111. 0.2264 , , substance gave 0.4967 , , carbonic acid and 0.1387 , ,,water. Per-centage composition I. 11. 111. Carbon. . 60.14 60.03 59-85 Hydrogen . . 6-66 6.77 6-80 A determination of the nitrogen according to Bunsen's method gave the following results Level in Vol. Level of Vol. at 1m tube. corr. mercury Temp. Bar. press. and 00. in trough. C. Mixture of car- 7 and nitrogen 137 136.3 249.5 9-0 779*lmm89.6606 moist. Dry nitrogen. 19.4 17.2 250.0 9.5 773.5mm 9.362 Ratio of carbon and nitrogen equivalents 89*6606-9*362 9.362 = 100 Calculating from the mean per-centage of carbon found (60*01) this ratio leads to 16.3 per cent of nitrogen. Although this result is not so near as those usually obtained I mention it as a confirmation of the formula resulting from the above analyses which is c, HI2 N2 04 Or c, as will be evident from the following table MR.MALTLE ON NITROMESIDINE. -Theory. Mean of experiments. 18 equivs. Carbon . . 108 60.00 60.01 12 , Hydrogen . 12 6-67 6.74 2 ,y Nitrogen. . 28 15.55 16.31 4 , Oxygen . . 32 17.78 -I , Nitromesidine . 180 100*00 Properties of Nitromesidine.-This substance is obtained when pure in long needle-shaped crystals of a golden yellow colour. The crystals fuse iiito a liquid at a temperature below 100° C. (212O F.) and solidify on cooling into a mass of radiated needles. They are very soluble in alcohol and ether and also slightly so in water to which they impart a faint yellow colour.Nitromesidine volatilizes without decomposition at looo C. (212OF.) its vapour burns with a bluish flame. Its solutions are neutral to test paper and have an unpleasant bitter taste. Compounds of Nitromesidine.-Nitrornesidine dissolves readily in acids forming crystalline salts; its basic power is however very feeble most of its salts are readily changed; all those which I have obtained with the exception of the platinum double salt and the phosphate are actually decomposed by mere contact with water. They are soluble in alcohol and their solutions possess an acid reaction. Hydrochlorate of Nitromesidine.-To prepare this salt the base is dissolved in dilute hydrochloric acid and the solution evaporated. When now allowed to stand the salt crystallizes in colourless needles.This salt being decomposed by water the solution was evaporated to dryness on the water bath and allowed to remain until the free acid was completely expelled. It mas then dried at looo C. (212OF.) 0.3148 grm. of the salt gave 0.5716 , carbonic acid and y 0-1703 , water. y 0.1593 , , the salt gave 0.1051 , , chloride of silver. The above analysis corresponds with the formula c1 H, N 0 HCI as the following table shows Theory. Experiment. -18 equivs. Carbon . . 108.0 49.89 49.52 13 , Hydrogen . 13.0 6.00 6.01 ' JJ Nitrogen . 28.0 12.93 --4 , Oxygen . 32.0 14.78 I , Chlorine . 35.5 16.40 16-32 --I-.-L , Hydrochloratc 216.5 100.00 Richloride of Platinum und N~li.osnesidine.-When an excess of bichloride of platinum is added to a hot saturated solution of the above salt the liquid on cooling deposits the double salt of nitro-mesidine and bichloride of platinum in groups of yellow crystals.To free the salt from an excess of bichloride of platinum it was washed with water and afterwards crystallized from alcohol. TOcontrol the formula and ascertain the atomic weight of the sub- stance four careful determinations of platinurn were made in speci- mens of the salt prepared at different times. I. 0.2122 grm. of platinum salt yielded 0-0544 , , platinum. 11. 0.2587 , , platinum salt yielded 0.0661 , , platinum. 111. 0.1625 , , platinum salt yielded 0.0410 , , platinum. IV. 0.1806 , , platinum salt yielded 0.0462 , , platinum.V. 0.3358 , , platinum salt yielded 0.3470 , , carbonic acid and 0.1083 , , water. VI. 0.3741 , , platinum salt yielded 0.3838 , , carbonic acid and 0.1167 , , water. These numbers give for 100 parts I. 11. 111. IV. V. VI. Platinum . 25-63 25.55 25.23 25.58 -Carbon . . --28.18 27.97 Hydrogen . --3.58 3.46 leading to the formula c, HI2 N2 04 HC1 Yt Cl, as the following calculated numbers will shew Theory. Mean of experiments. 18equivs. Carbon . . 108-00 27-96 28.07 13 , Hydrogen . 13.00 3.36 3.50 2 , Nitrogen . . 28.00 7’025 -4 , Oxygen . . 32.00 8.30 -1 , Platinum . . 98.68 25.55 25.49 3 , Chlorine . . 106.50 27.58 -1 , Platinum salt 386.18 100°OO Sulphate of Nitrornesidine.-When the base is dissolved in boiling dilute sulphuric acid the solution deposits on cooling white silky .- AIR.ilIAULE OX NITROBIESIDINE. crystals of the sulphate. This salt is deconiposed by water the base being separated ;its analysis was therefore abandoned. Nitrate of Nitromesidine.-This salt is formed when nitromesidine is dissolved in dilute nitric acid. The solution on being evaporated with an excess of free nitric acid is decomposed when the evapora- tion reaches a certain point red nitrous fumes being disengaged and a red oily product of decomposition remaining. Tribasic Phosphate of Nitrornesidine.-When the base is dissolved in a solution of phosphoric acid the salt crystallizes in leafy crystals of a beautiful lemon-yellow colour.It may be washed with water without decomposition. The salt after the removal of the free acid is perfectly pure. A portion of the salt dried at 100' C. (212O F.) gave the following results I. 0.2471 grm. of the salt gave 0.4580 , , carbonic air and 0.1413 , , water. 11. 0.3058 , , the salt gave 0.0529 , , pyrophosphate of magnesia which agree with the following formula 3 (H c, HI N o,>,PO as is shown by reference to the following numbers Theory. Experiment. -54 equiv. of Carbon . . . 324.0 50.70 50.54 39 , , Hydrogen . . 39.0 6.10 6.35 6 , , Nitrogen . . . 84.0 13-14 -20 , , Oxygen . . . 160-0 25.06 -1 , , Phosphorus . . 32.0 5.00 4-86 1 equiv. of Phosphate . . 639.0 100*00 If a large excess of phosphoric acid be employed an acid salt is obtained which appears to contain only one equivalent of nitro- mesidine.Products of Decomposition of lVitromesidine.-The small quantity of substance at my command and the tedious processes requisite to obtain nitromesidine have prevented my studying to any great extent the products of its decomposition. Action of Bromine and Chlorine on Nitromedine.-When nitro-mesidine is brought into contact with bromine a violent action takes place and the resulting compouiid is a dark oily substance. This reaction is interesting as showing the difference between nitromesidine and its isomeric compound nitrocumidinc ; the latter substance \\hen acted on by bromine yielding a crystalline solid. MR. MAULE ON NITROMESIDINE.An alcoholic solution of nitromesidine when exposed to the action of chlorine y-ields a pinkish solid which is soluble in boiling ether and from which it separates on cooling. The reduction of trinitromesitilole by hydrosulphuric acid appeared of great interest since no nitro-compound containing 3 atoms of hyponitric acid has up to the present moment been subjected to such treatment. Trinitromesitilole is very difficult of reduction ; I have submitted a considerable quantity of the substance to the action of hydrosulphuric acid for several weeks and foundat the end of that period a very small quantity had been acted on. I have however obtained a sufficient quantity of the product to establish the existence of a basic compound produced from trinitromesitilole although the small amount of this substance and the difficulty of obtaining it sufficiently pure has compelled me to defer its examination to a future period.

ISSN:1743-6893    

DOI:10.1039/QJ8500200116

出版商:RSC    

年代:1850

数据来源: RSC

摘要:

MR. MAULE ON NITROMESIDINE. March 3 1849. The President in the Chair. August W. Hofmann Ph.D. was elected a member of the Society. The following papers were read XHL-On the compounds containing Phosphorus and Nitrogen. BY J. H. GLADSTONE,Ph.D. Davy was the first to describe any of the combinations containing both-phosphorus and nitrogen and since his time the subject has engaged the attention of Rose,* Liebig,? and Gerhardt.1 Whilst the singularity of their composition and the remarkable stability which could not have been anticipated in such compounds give them a peculiar interest there exist great discrepancies between the accounts of them given by different chemists. At the instigation of Professor Liebig I commenced some time ago an examination of the matters in dispute and I have subsequently been led to extend my researches I shall now lay before the Society my investigations upon some of the doubtful points and I hope shortly to present a second communication upon other compounds into which the same two elements enter.When pentachloride of phosphords is thoroughly saturated with dry ammoniacal gas a bulky white powder is produced consisting of * Poggendorf's Ann. Vol. xxvrn. p. 529. t Liebig's Anualen Vol. XI. Part. 2. Ann. de Chimie 3me. SQr.Octobre 1846. 122 DR. GLADSTONE ON THE COMPOUNDS chloride of ammonium chlorophosphuret of nitrogen and a peculiar substance which when thrown upon a filter and washed for a long time with hot water is resolved into chloride of ammonium and a white insoluble powder containing no chlorine in its composition.Wohler and Liebig the first discoverers of this latter substance were led to regard it as the hydrate of the phosphuret of nitrogen bearing the formula N P (2 €10). Gerhardt on the contrary assigns to it the composition PH N 0, being in fact phosphate of ammonia minus five atoms of water 2 (NH 0)PO -5 HO = PN H 0,; and although not containing the elements of amidogen he terms it phosphamide. Two methods of preparing the substance from the bulky white powder are given. The one consists in washing it with hot water until no more chloride of ammonium is produced; but as the washing may continue for a fortnight before perfect purity is obtained this process has the disadvantage of being very tedious.Or it may be boiled alternately with potash and nitric acid until a portion after being washed dried and heated in a tube gives no sublimate of chloride of ammonium ; this process however proved very destructive to the sub- stance itself The plan I found preferable was first to purify the powder from chlorophosphuret of nitrogen which is an invariable con- comitant either by dissolving out the latter with ether or as is better by boiling the whole mass in water when the chlorophosphuret is volatilized along with the steam; and then to keep the substance immersed in water in brisk ebullition for five or six hours. As the liquid containing the solid matter is subject to very violent succussions it will be found advantageous not only to adopt the usual prel-entatives but to place it in a capacious flask and suspend it over the flame.And as continued boiling exerts a destructive influence upon the new product itself it is desirable not to protract it beyond the time when the conversion is complete which may be ascertained as above. The white powder thus produced shows no disposition to combine with alkalis or acids; it is insoluble in alcohol and oil of turpentine as well as in water but when boiled with the latter it is very slowly decomposed p.hosphoric acid and ammonia remaining in solution. This decomposition takes place rather more rapidly if caustic potash be present ammonia being of course in that case evolved. Sulphuric acid has no effect upon it in the cold but when heated decomposition ensues the solid matter entirely disappears and phosphoric acid and ammonia arc found in the solution no sulphurous acid is evolved during the decomposition but the solution is dark coloured.The sulphuric acid rnay be only very slightly diluted in order to CONTAINING PHOSPHOKUS AND NITROGEN. 123 obtain this effect. When fused with caustic potash ammonia is given off and phosphate of potash formed. If heated per se in the open air or even in oxygen gas it is not burnt but ammonia is given off and a new compound remains this action will be reverted to presently. If the powder thus heated be moist the elements of water take part in the transformation ammonia is given off as before and metaphosphoric acid is found in the tube; but I never obtained as Gerhardt describes a complete conversion of the substance into phosphate of ammonia ; some dark coloured insoluble matter always remained.Chlorine gas has no effect upon it either in the cold or at any temperature insufficient to decompose the substance itself. A1though containing both phosphorus and hydrogen it resists the action of most oxidizing agents. It is not affected by boiling in strong nitric acid nor by a mixture of sulphuric and nitric acids when fused with nitre it is but slowly oxidized; but it deflagrates when heated with chlorate of potash. This difficulty of decomposition rendered the analysis of the substance and especially the determination of the phosphorus no easy task. The method followed by Gerhardt namely that of igniting the substance with oxide of lead and nitric acid gave me a result indicating 37.9 per cent of phosphorus but the mass left in the crucible was not wholly soluble in nitric acid and I have reason to believe that one of the products of the action of heat is formed which of course would completely vitiate the result.Combustion with oxide of copper is quite inadmissible for the same reason. The following estimations however were severally obtained by a different method the substance analyzed being dried in each instance by the heat of a water-bath. I. 0.4245 grm. of substance prepared by the boiling process was fused in a silver vessel with pure hydrate of potash until all odour of ammonia disappeared.The phosphoric acid was converted into phosphate of baryta and bcing estimated in the usual manner was found to be 0.306 grm. 11. 0.2485 grm. of the same oxidized by means of a mixture of about 1 part chlorate of potash and 3 parts nitre gave of phosphoric acid estimated in the same manner 0.178 grm. 111. 0.267grm. of the same Substance was decomposed by heating with strong sulphuric acid which was then largely diluted the sulphuric acid having been removed by means of acetate of lead the phosphatc of lead mixed with oxide was analyzed. This yielded 0.1828 grm. phosphoric acid. This method however is subject to several inaccuracies. DR. GLADSTONE ON THE COMPOUNDS IV. 0.2028 grm. of substance prepared by alternate boiling with acid and alkali was first heated per se and the grey powder thus produced was oxidized by fusion with nitrate of potash.The phos-phoric acid estimated by means of baryta salt was 0.1482 grm. These numbers give the following results per cent; the equivalent of phosphorus being always taken at 32 on the hydrogen scale. I. XI. 111. IV. Phosphorus . 32-04 31.83 30.41 32-44 The amount of hydrogen in the substance under examination was easily determined by combustion with chromate of lead. I. 0.4025 grm. of substance prepared by long washing with hot water and dried at loooC.,yielded 0.121 water. 11. 0.3435 grm. of substance prepared by the boiling process yielded 0.1035 water. 111. 04385 grm. of the same dried at a temperature of 140° C. (284O F.) so as to render the presence of accidental moisture impos- sible yielded 0-1405water.These numbers give the following for 100 parts I. 11. 111. Hydrogen . . . 3.34 3-35 3.56 These results differ materially from those of both Liebig and Gerhardt. The amount of nitrogen was determined by conversion into ammonia according to Will’s process . I. 0.3195 grm. of substance prepared by long washing and dried at 1000 C. was burnt with soda-lime and yielded 0.6835 grm. of reduced platinum. 11. 0.502 gri. of substance prepared by the boiling process yielded 2.1825 grms. of double salt of platinum and ammonium. 111. 0.443 grm. of the same heated first per se and afterwards fused with pure potash the gas evolved being in both instances collected in the usual hydrochloric acid apparatus yielded 1.956grms.of double salt. IV. 0.3155 grm. of a fresh sample prepared by the boiling process burnt with soda-lime yielded 1.505 grms. of double salt. These numbers calculated upon 100 parts give I. 11. 111. IV. Nitrogen . . 30.31 27.29 27*69 29.92 It is worthy of remark that this result accords with the number CONTAININQ PHOSPHORUS AND NITROGEN. 125 obtained by Liebig who estimated the nitrogen as a gas 28.526 &c. a result however upon which he placed little reliance. There is sufficient discrepancy in these numbers deduced from experiment to show that the substance operated upon was not perfectly uniform ; but as it appears insoluble in any menstruum and incapable of crystallization I have been unable to devise any means of purifying it.The results however agree sufficiently to place the fact beyond doubt that the proportions in which the phos- phorus nitrogen and hydrogen are combined is as P :H :N, but united with a larger amount of oxygen than the two atoms assigned it by Gerhardt. Indeed the amount obtained by me of each of the elements in question is far below and quite incompatible with that given by him. The numbers accord most closely with those deduced from the formula P H N 0 Phosphorus . . 32-32 Hydrogen . . 3.03 Nitrogen . . 28.28 Oxygen . . 36.36 The real composition of the substance is probably PH N 0, with which the majority of the results are not incompatible. By experiments from subst.produced Calculated. by boiling process. Phosphorus . 32 31-07 32-04 31-83 30.41 Hydrogen . 3 2.91 3.35 3.56 -Nitrogen . 28 27-19 27.29 27.69 -Oxygen . . 40 38-83 -c -103 100*00 This view is strengthened when we consider that in the formation of the white powder,oxidation must have taken place during sonie 'part of the process as will be evident from the annexed equation; now it is very possible that the oxidation has not been in all instances complete which will readily account both for the variations in the analytical results and for their discrepancy with theory. P C1 & 7 NH & 2 HO & 30 = 5 (NH Cl) & PH N 0,. The simultaneous formation of chlorophosphuret of nitrogen throws no light upon this reaction. As the substance operated upon in all these analyses was dried at a somewhat high temperature the objection might be urged that the oxidation really took place during that process.It became 126 DR. GLADSTONE QN THE COSfPOUNDS desirable therefore to dry it in some other manner. When left for any length of time between sheets of blotting paper at the ordinary temperature it still retains a considerable quantity of moisture. A portion was therefore allowed to remain in vacuo over sulphuric acid for seven days; it was then weighed and exposed freely to the air in an oven at the temperature of looo C. for an hour. No change took place; and upon being heated to low redness in a tube closed at one end it gave a grey powder weighing 84.6 per cent of the original substance a result coinciding (as will be presently seen) with that obtained from it when dried in a water-bath thus proving that the white powder is identical whether dried at looo C.or in vacuo over sulphuric acid and that the oxidation must be sought for in some earlier part of the process. B IPHOSPHAMIDEm The fact that a new substance different in properties from that just described is produced by the action of heat upon the latter has already been incidentally remarked. This substance has been named “Biphospharnide;” by Gerhardt he states that it is formed by the separation of all the hydrogen and half the nitrogen from phosphamide and has the composition PNO,. His account of the formation1 find to be true but it is evident that if my determina- tions of the composition of the original substance be correct it is impossible that Gerhardt’s formula can be the true expression for this new one.When the substance of which the analysis has just been given is rapidly heated per se to incipient redness it gives off ammonia and a gritty grey powder remains. This takes place whether the experi- ment be conducted in air or oxygen gas or in hydrogen carbonic acid or chlorine; in the case of the two latter gases volatile ammo- niacal compounds being of course formed. To prepare the new body, the substance (phosphamide) should be heated either in a narrow tube closed at one end or better in a gas containing no oxygen in order to avoid the partial establishment of a reaction which will be subsequently described.The proportion of the new substance remaining I found to be as follows I. 0.211 grm. of the white powder dried in a water bath heated in a test tube yielded 0.176 grm. of the new substance. 11. 0.365 grm. of the one heated in the same manner yielded 0.3055 grm. of the other. CONTAINING PHOSPHORUS AND NITROGEN. 127 111. 0.2028grm. heated in hydrogen gas yielded 0.1695 grm. IV. 0.2025 grm. of a separate preparation heated in a stream of carbonic acid yielded 0.1675 grm. These figures show that the new substance forms respectively 83.4 83.7 83.6 and 82-7 per cent of the original; thus coinciding with the number deduced from theory supposing PN H 0 to lose one equivalent of ammonia and become PNO, viz.83.5. The last of the four results rather favours the view that the original substance has the composition P H N 0, and the new one that of P N 0, in which case the reduction would be to 82.9 per cent. Two attempts were made to estimate the amount of ammonia evolved by collecting the gas in an ordinary hydrochloric acid appa- ratus affixed to the little tube in which the substance was heated; but the last portions of ammonia always come off with difficulty and it appeared that the slight pressure exerted by the liquid in the apparatus was sufficient to prevent the alteloation being complete. The amounts remaining in the tube were respectively 86.8 and 86-4 per cent the loss being therefore 13.2 and 13.6 per cent and the am- monia actually in combination with the hydrochloric acid amounted to 10.9 and 12.8 per cent respectively.This discrepancy is explained by the fact that upon the first heating of the substance a little water is always given off; this I found to take place even when the original substance had been exposed for some time to a temperature above looo C. so that it could not arise from accidental moisture. In the first instance the water was collected in a tube filled with sticks of caustic potash which was placed between the hydrochloric acid apparatus and the tube in which the experiment was conducted the amount was 1-8per cent. In the second experiment the quan- tity although not directly estimated was evidently much smaller. Analysis confirmed the view taken of the composition of this substance.I. 0.1695 grm. deflagrated with nitrate of potash and the phos- phoric acid estimated by means of baryta yielded 0.1432 grm. of the acid. 11. 0,2262grm. burnt with soda lime yielded 0.589 grm. of double chloride of platinum and ammonium. A portion mixed with chromate of lead and heated produced no water; therefore it may be concluded that the substance does not contain hydrogen. These figures calculated upon 100 parts give the annexed which will be found to be somewhat higher than those deducible from Dlt. GLADSTONE ON THE COMPOUNDS the formula PNO, though not so high as those required by p N 0,. Calculated. Experimental. Calculated. PNO I. 11. pz N2 0, Phosphorus . . 37.21 38.82 -39-03 Nitrogen .. 16.28 -16.33 17.07 Oxygen . . 46-51 -43.90 This substance like that from which it is derived is insoluble in all the ordinary menstrua nor does it form compounds with acids or alkalis. When boiled with a solution of potash it is unaffected; when fused with the solid hydrate ammonia is evolved and phos- phate of potash formed. It is decomposed by boiling sulphuric acid but not without difficulty the solution becoming very black and a little sulphurous acid being evolved. It resists the oxidizing action of strong nitric acid but deflagrates when fused with nitre. When subjected to a full red heat it fuses and upon cooling rernains as a black vitreous mass; but even though the experiment be conducted with free access of air as for instance on a piece of platinum foil no combustion or other alteration takes place ; the weight remains the same.If before heating the substance it be moistened with a little water a transformation into phosphoric acid and ammonia takes place as with the compound from which it is derived but in this case also I did not find the change to be complete. Chlorine has no action upon this body; if it be heated in a current of that gas the weight remains the same. If mixed with iodine or sulphur and heated the metalloid sublimes without producing any change. If heated in a stream of hydrosulphuric acid gas the grey powder assumes a dark semi-fused sticky appearance and increases somewhat in weight. For this experiment the gas should be made from sulphide of anti- mony in order to avoid the admixture of hydrogen which has a widely different effect upon the substance under examination.If the powder be heated in a current of this latter gas a peculiar action is soon instituted ammonia is given off and subsequently white fumes pass along the tube in which the experiment is conducted consisting of phosphoric or perhaps phosphorous acid mixed with spontaneously inflammable phosphuretted hydrogen ;in the mean time a red subli- mate apparently impure oxide of phosphorus is formed in the tube and sometimes a small quantity of water condenses. In one instance I obtained no sublimate and no phosphuretted hydrogen was evolved but much phosphoric acid and water were produced. CONTAINING PHOSPHORUS AND NITROGEN.This action may continue for a long tinic but a portioii always remains which resists the further influence of the hydrogen. It is of a dark brown COIOUT insoluble in water and combines neither with acids or alkalis; it is slowly decomposed by strong nitric acid yielding phosphoric acid ; when fused with caustic potash some ammonia is evolved thus proving that the nitrogen has not wholly departed but it is not rendered wholly soluble by this fusion with potash; when heated with chromate of lead no water is formed thus showing that hydrogen has not entered into its composition This is not the only conversion which ‘‘phosphamide” undergoes by the influence of heat. If atmospheric air have free access to it while the temperature is slowly raised a totally different result is obtained.At about 150 C.(302OF.) the substance begins to evolve ammonia and to increase in weight; if the heat be now maintained at any point between that and perhaps one hundred degrees (C.) higher for half-an-hour or even longer ammonia will continually be evolved and the weight will constantly increase. The resulting substance has a somewhat dark appearance and is resolved by water into two portions-the one soluble,- the other insoluble and identical with the grey powder formerly described. The proportionate amount of the two depends upon the degree of access which air has to the substance during the process and also upon the rapidity with which the beat has been raised. It is evident that the mere amount of increase in weight will afford no foundation upon which to calculate the amount of oxygen absorbed.In one instance however when there was very little of the grey powder produced the increase was found to be as much as 22.8per cent. As ammonia had been given off during the whole process the oxygen absorbed must have been very con- siderable. The aqueous solution contained merely a trace of free acid when evaporated to dryness it gave a crystalline mass con-sisting in a great measure of phosphate of ammonia. No portion was soluble in alcohol. PHOSPHURET OF NITROGEN. When the compound produced by saturating chloride of phos-phorus with amrnoniacal gas is heated to redness or when the substance formed by passing the vapour of terchloride of phosphorus through a tube filled with pure chloride of ammonium at a tempe-rature nearly sufficient to volatilize the salt is washed and heated to redness a substance is produced which Rose named phosphuret of nitrogen believing it to have the composition PN, although he never VOL.11.-NO. VI. K 130 DH. OLADSTONE ON THE COMPOUNDS mcceeded in obtaining it absolutely free from hydrogen. Gerhardt however regards it as a substance of the composition PKN, (phos-phnm) mixed with a quantity of his ‘‘biphosphamide,” which con- tains none ofthe element in question and as the amount of hydrogen required by such a formula is 1.64 per cent. and that given in the re- corded experiments varies about 0.7 per cent. it is evident that we must suppose the “phospham” to be contaminated with about its own weight of “biphosphamide.” He affirms that the admixture of this latter substance is to be expected a priori from the extreme avidity for moisture which both chlorides of phosphorus display and the impossibility of keeping them in a perfectly dry atmosphere during the whole of the process.Now it remains yet to be shown that “biphosphamide,” ie. my grey powder can be formed from oxychloride of phosphorus phosphorus or phosphoric acids which are the veritable products of the action of water upon the two chlorides in question; and in the total absence of all positive proof we are not without evidence to the contrary. For if the statement of Rose be correct that phosphuret of nitrogen is decomposed and rendered wholly volatile by sulphuretted hydrogen it is impossible that it should be composed in a great measure of this grey powder which I find not to be so affected and the same remark will hold good in reference to the action of hydrogen though this is I con-ceive not so conclusive as the other.When it is remembered that the amount of hydrogen found in the analysis of this substance is always very small and in fact in one of Rose’s determinations did not exceed 0.25 per cent. I see no sufficient ground for doubting the correctness of the formula given by that chemist. There are no direct means for ascertaining the composition of the chlorinated product from which the ‘c phosphamide” is derived owing to the impossibility of obtaining it in a pure state.Gerhardt assigns to it the formula PCl N H, calling it ‘I chlorophospha-mide;” but as the theoretical grounds upon which he based his conclusion prove to be incorrect this is probably not the true ex- pression; though I must add such a view is not incompatible with my results. I subjoin in a tabular form what I conceive to be the true com-position of those two compounds of phosphorus and nitrogen which I have minutely examined together with the formula assigned by Rose to his “phosphuret of nitrogen.” I have not altered the names given to these substances by former investigators although they are manifestly inappropriate since I am not satisfied respecting their theo- retical constitution and any new name must involve a theory. CONTAINING PHOSPHORUS AND NITROGEN.Gerhardt’s name. I Other appellations. Composition. I I Liebig‘B hydrate of phosphuret phos~hamide. of nitrogen } PN,H,O Biphosphamide. “Gray powder.” PN 0 Phospham. Rose’s phosphuret of nitrogen. PN Nom.-In drying this substance I repeatedly witnessed an elec- trical phenomenon. It was my practice to place a portion of the powder on a watch-glass and expose it thus in an oven at a tempe- rature of loooC. When thoroughly dried if the watch-glass be removed from the oven and the finger drawn across the bottom of it the powder will become excited and portions of it will in all pro- bability be projected over the sides of the glass. If the watch-glass be covered by another of the same size as was my practice for weigh- ing the substance and either the upper or under one be rubbed the phenomena of attraction and repulsion are beautifully seen.Of course the watch-glass may be rubbed with silk woollen cloth dry wood or any other electric with a similar effect.

ISSN:1743-6893    

DOI:10.1039/QJ8500200121

出版商:RSC    

年代:1850

数据来源: RSC

摘要:

CONTAINING PHOSPHORUS AND NITROGEN. XIV.-On Phospho-cerite a new Mineral containing Phosphate of Cerium ;with Observations on the Separation of Cerkurn Lan-thanum and Didymium. By HENRYWATTS,B.A. Assistant in the Birkbeck Laboratory University College. The mineral which forms the subject of the following commu- nication is contained in the cobalt ore of Johannisberg in Sweden ; and remains as a residual product when the ore after calcination is treated with hydrochloric acid for the purpose of extracting the cobalt. It does not form more than one-thousandth part of the whole substance. It was discovered some years ago by Mr. Ollive Sims,* of the Staffordshire Potteries and sent to Professor Graham to whose kindness I am indebted for the opportunity of examining it.Mr. Sirns believes that it likewise exists in the cobalt-ore of Tunaberg. The substance in question is a greyish-yellow crystalline powder intermixed with a small quantity of dark purple crystals of another * Transactions of the Chemical Society vol. I. p. 7. K2 MR. HENRY WATTS ON PHOSPHO-CERITE. substance. The purple crystals are strongly attracted by the magnet and with a little care and patience may be easily separated from the others by moving a magnet through the entire mass. The yellow particles when examined by a powerful microscope are found to consist of crystals belonging to the square prismatic system. Two forms appear to occur with tolerable frequency one a square-based octohedron ;the other a square prism with four-sided pyramidal summits.The specific gravity of these crystals is 4.78; their degree ofhard-ness is intermediate between 5.0 and 5*5.* The dark-coloured magnetic crystals are perfectly opaque ;and when viewed by the microscope exhibit the form of the rhomboidal dodeca- hedron which is one of the crystalline forms of magnetic iron ore some of them however have a pyramidal shape. They are soluble in hydrochloric acid the solution containing iron in the form of ferroso-ferric oxide (Fe OJ and cobalt. The presence of the latter metal is also easily recognised by the blow-pipe. The yellow transparent crystals evidently constitute the essential part of the mineral they were analysed as follows. QUALITATIVE ANALYSIS. A quantity of the yellow crystals having been reduced to a very fine powder so as completely to break up the crystalline structure the powder was subjected to the action of various solvents.It is insoluble in water. Strong nitric acid at a boiling heat dissolves it sparingly ; strong hydrochloric acid somewhat more readily. But the best solvent for this substance is concentrated sulphuric acid. A quantity of this acid having been diluted with water to free it from sulphate of lead the powder was boiled in it till the whole was reduced to a pasty mass. This was left to cool water poured upon it and the whole left to stand for a few minutes. The greater part of the solid matter was then found to be dissolved. The liquid when it had become clear was poured off the residue again treated with sulphuric acid &c.; and this treatment repeated till a residue was left on which the acid exerted no further action. A. The acid solution was next subjected to the usual course of analysis by means of hydrosulphuric acid sulphide of ammo-nium &c. * For the above determinations of the crystalline form and hardness of the mineral I am indebted to Mr. Edward Chapman of Kensington. MR. HENRY WATTS ON PHOSPHO-CERITE. a. Hydrosulphuric acid threw down nothing but a trace of copper. b. Sulphide of ammoniuiu gave ,a copious black precipitate ; and this being dissolved in aqua regia gave a yellow solution in which ferrocyanide of potassium showed the presence of iron in small quantity. Ammonia added in excess to this solution produced a buff-coloured precipitate and a pinkish solution.This solution was found to contain a small quantity of cobalt. The buff-coloured precipitate was boiled in caustic potash ; but nothing was dissolved- Fused with borax before the blow-pipe it gave in the outer flame a glass which was reddish-yellow while hot but became colourless on cooling in the inner flame a perfectly colourless glass was produced. These characters might be due to the iron present. It was evident however that the precipitate contained something besides iron; and its insolubility both in potash and ammonia rendered the presence of earthy phosphates barates &c. probable. Boracic acid was therefore searched for in the usual way ; but none was found.The presence of fluorine was impossible since the mineral had been boiled in strong sulphuric acid The mineral itself was likewise carefully examined for fluorine but gave no indication of its presence. To search for phosphoric acid it was necessary to separate the bases. For this purpose I dissolved a portion of the buff-coloured precipitate in hydrochloric acid and added oxalate of ammonia to the solution. This produced a copious precipitate; and I found that this same precipitate was produced even when the solution was very strongly acid a large excess of acid merely rendering it necessary to add a greater quantity of the reagent. Oxalic acid acted in the same manner as oxalate of ammonia. The precipitate thus obtained was of a very peculiar character.It was at first bulky and of a curdy consistence like chloride of silver; but quickly became crystalline and sank down to the bottom of the vessel it was nearly white but had a perceptible tinge of violet. It was collected on a filter washed and dried and then ignited. It then underwent a remarkable change becoming first black then yellow and acquiring an almost fluid consistence; the fine solid particles floating as it were in an atmosphere of the gases which were escaping.* Finally the whole became tranquil and assumed a dark brown-red or tile-red colour. This brown-red substance fused with borax before the blow-pipe * Translation of Gmelin’s Chemistry vol I. p. 212 note. MR. HENRY WATTS ON PHOSPHO-CERITE. gave the characters already mentioned.Digested in hydrochloric acid it remained unaltered in the cold; but on the application of a gentle heat it dissolved with copious evolution of chlorine. The solution was yellow at first but assumed a violet tint after longer boiling. It was then mixed with a tolerably strong solution of sulphate of potash which in a few minutes threw down a copious white crystalline precipitate insoluble in an excess of the reagent. All these characters distinctly prove that the brown-red substance obtained as above consists wholly or in great part of Oxide of Cerium. As however zirconia yttria and thorina are likewise precipitated by oxalic acid from acid solutions it was necessary to ascertain whether these substances were associated with the cerium or not.The solubility of the brown-red powder in hydrochloric acid proved the absence of zirconia ; for that substance after ignition is insoluble in all acids except concentrated sulphuric acid. Yttria is like cerium precipitated by sulphate of potash; but the precipitate is soluble in an excess of sulphate of potash. To ascertain therefore whether it was present a saturated solution of cerium in hydrochloric acid was mixed with a saturated solution of sulphate of potash and a crystalline crust of that salt introduced in such a manner as to be in contact with the liquid throughout its whole depth. The whole was left to stand for several days and then filtered. The filtrate mixed with excess of caustic potash gave no precipitate therefore no yttria was present.The absence of thorina is proved in the same nianner as that of zirconia; for thorina after ignition is insoluble in all acids except strong sulphuric acid. The presence of Lanthanum and Didymium the metals usually allied with cerium was easily proved by methods hereafter to be described. It is interesting to find that these metals are associated with cerium in this hitherto unknown mineral as well as in the Cerites Orthites &c. in which they have previously been dis-covered. It seems to show that the association of these three metals is not merely fortuitous but exists in consequence of a reguiar law. The acid liquid from which the cerium &c. had been separated by oxalate of ammonia was next examined for phosphoric acid.For this purpose a portion of it was tested with ammonia and sulphate of magnesia which produced a copious crystalline precipitate indi- cating the presence of phosphoric acid To obtain additional proof of this however the remaining portion of the acid liquid was mixed with perchloride of' iron and excess of ammonia. The precipit,ate was thoroiighly washed to reiiiuve a11 traces of soluble chlorides and then Mlt. HENRY WATTS ON PHOSPHO-CERITE. decomposed by digestion in sulphide of ammonium. The liquid filtered from the sulphide of iron thus produced was boiled with nitric acid and filtered again to free it from sulphur. The filtrate treated with nitrate of silver and a small quantity of ammonia gave the characteristic yellow precipitate of tribasic phosphate of silver.It appears then that the matter precipitated by sulphide of am-monium mainly consists of phosphate of cerium. c. The liquid filtered from the black precipitate (b) produced by sulphide of ammonium was boiled with an excess of hydrochloric acid and filtered to separate sulphur j the filtrate was evaporated to dryness and ignited to expel ammoniacal salts. A trifling fixed residue was left which appeared to be magnesia; but the quantity was too small to give distinct indications. B. The matter insoluble in sulphuric acid was examined in the usual manner by fusion with carbonate of soda it consists chiefly of silica with small quantities of iron alumina and lime and a trace of magnesia. It is merely sandy or argillaceous matter contained in the ore and mechanically mixed with the crystalline powder.The mineral appears then to consist essentially of Phosphate of Cerium (including lanthanum and didymium). The small quantity of cobalt found associated with it is merely accidental ;its presence is easily accounted for when we remember the source of the mineral itself. The iron which is in somewhat larger quantity is probably contained in the substance of the crystals; its quantity though not very great is too large to be accounted for by the accidental presence of any magnetic particles which might have escaped the searching action of the magnet. I propose to call this substance PHOSPHO-CERITE. QUANTITATIVE ANALYSIS. A convenient quantity of the yellow crystals separated as com-pletely as possible from the magnetic particles was reduced to a state of exceedingly minute division by pounding in an agate mortar and subsequent levigation.The fine powder thus obtained having been thoroughly dried at a gentle heat a quantity of it was weighed out amounting to 51.46 grains. It lost nothing by strong ignition. It was dissolved as completely as possible in sulphuric acid as in the quantitative analysis. The insoluble matter weighed 1.52 grains or 2.96 per cent. The cerium &c. was precipitated by oxalate of ammonia and the oxalate converted by ignition into sesquioxide of cerium associated MR. IiENILY WATTS ON PHOSPHO-VERITE. with lanthanum and didyniium. It weighed 35-76 grains. Now the atomic weight found by Berzelius and Hisinger for cerium-at a time when the existence of lanthanum and didymium was unknown and that which is now known to be a mixture of the three metals was regarded as a single metal-is on the hydrogen scale 46.Hence the atomic weights of the protoxide and sesquioxide of cerium (using that term in its former sense) are to one another as 46 + 8 46 + 12,oras54 58. Now 58 54 35.76 33.29 Hence the quantity of protoxide of cerium or rather of the pro- toxides of the three metals taken together is 33.29 in 51.446 grains of the mineral or 64.98 per cent. I have not attempted to determine the relative quantities of the three oxides. In the present state of our knowledge indeed this determination is impossible ; partly because the individual atomic weights of cerium lanthanum and didymium are unknown ;partly because all the processes of separation hitherto devised are so tedious and complicated and attended with so much unavoidable loss from the multitude of decantations filtrations and washings which they involve that their application in quantitative analysis is quite out of the question.The cerium &c. having been separated as above the filtered liquid was neutralized with ammonia and sulphide of ammonium added The precipitate was digested in nitric acid and ammonia added in excess. The precipitate of peroxide of iron thus produced weighed 1.50 grains corresponding to 1.45 grains or 2-83 per cent. of magnetic oxide Fe 0, the state in which the iron most probably exists in the mineral.The ammoiiiacal solution filtered from the iron precipitate yielded a small quantity of oxide of cobalt with a trace of copper amounting to 0.23 gr. or 0.45 per cent. Lastly the filtered liquid containing the phosphoric acid was treated by Berthier’s process for determining the quantity of that acid the result was 14.65 grains or 28-46 per cent. We have then for the composition of the mineral in 100 parts Protoxides of cerium lanthanum and didyniiuni 64.68 Phosphoric acid . . 28.46 Oxide of iron (Fe 0,) . . 2.83 Oxide of cobalt &c. . 0.45 Sand stc. . . 2.96 99.38 Or disregarding the oxide of cobalt and thc matter iiisolublc in MR.. HENRY WATTS ON PHOSPHO-CERITE. 137 sulphuric acid as adventitious we find for the actual composition of the crystals Protoxides of cerium lanthanum and didymium 67.38 Phosphoric acid .. 29-66 Oxide of iron* . . 2.95 100~00 Notwithstanding the apparent accuracy of the preceding analysis it lrlust not be considered as more than an approximation to the truth. For the determination of the quantity of the associated bases rests upon the old atomic weight of cerium found by Berzelius and Hisinger. Now since that which was then regarded as a simple metal is really a mixture of the three metals whose several atomic weights are unknown and as the proportions in which the oxides of these metals are associated is by no means constaiit it is evident that the atomic weight of the compound metal must be liable to considerable variation; unless indeed the atomic weights of the individual metals are equal to each other a coincidence which though possible we have no right to assume.t It must however be remarked that the same uncertainty rests upon the analyses of all minerals containing cerium in the state of protoxide e.g. orthite allanite &c. If the number 46 be not the true expression of the atomic weight of the compound metal cerium all analyses of such minerals must be incorrect inasmuch as the cerium can never be estimated directly in the state of protoxide. But since these analyses have all the appearance of accuracy and have been made by chemists of unquestioned analytical skill (the greater number by Berzelius) it is scarcely probable that any very material error can have been committed in taking the number 46 as the atomic weight of cerium in the sense above-mentioned.The question * It is however by no means certain that the iron exists in the crystals themselves. I took all possible pains to remove the ferruginous particles by the magnet; but it is very possible that a small quantity of iron may have been diffused through the crystalline powder in the form of peroxide; if so the magnet would not have removed it. t Berzelius states on the authorityof Mosander that the atomic weight of lanthanum is greater than that of the combined metals and nearly equal to 680 on the oxygen scale or 54-4 on the hydrogen scale (Trait4 de Chimie 5e. Ed. Par. t. 11. p. 755). In a subsequent part of the same work (t.IV. p. 544) he says that the atomic weights of cerium lanthanum and didymium are unknown. In Gmelia’s Hand-book (Translation I 50) the atomic weight of lanthanum (or rather of lanthanum and didymium together) is said to be 36.1 and that of cerium 46.3. I mention these facts to show that the whole subject is beset with uncertainty and still open to investigat,ion. MR. HENRY WATTS ON PHOSPHO-CERITE must however remain undecided till the three metals shall have been obtained in a state of purity and their atomic weights indi- vidually determined. While this uncertainty exists with regard to the combining numbers of the bases me cannot of course arrive at any final conclusion respecting the atomic constitution of the mineral.If however we assume that the number 46 correctly expresses the atomic weight of the three metals considered as one (which may be denoted by the symbol M) and if we suppose that phospho-cerite is a tribasic phosphate of this metal viz. 3 MO PO, we shall have for its atomic weight 3 (46 + 8) + 71.38 = 162 + 71.38 = 233.38; and this reduced to 100 parts gives 69.41 MO + 30.59PO = 100. Now if in the preceding analysis we disregard the oxide of iron which even if it be contained in the substaiice of the crystals is too small in quantity to be considered essential to their constitution-in other words if we simply calculate the proportion of oxide of cerium &c. and phosphoric acid existing in the crystals we find as the result 69.44 310 + 30.56PO = 100.These quantities are almost identical with those above calculated from the formula 3 MO PO, differing in fact by only 0.03 per cent. VCTe cannot perhaps place very great reliance on this coincidence on account of the uncertainty above alluded to ;but it can scarcely be regarded as merely accidental. If the result be trustworthy it will go far to prove that the atomic weight of the compound metal cannot differ greatly from 46. If the view here taken be correct it Will follow that phospho-cerite is a mixture of the tribasic phosphates of cerium lanthanum and didymium. The isomorphism of these metals can scarcely be doubted; and it is therefore to be expected that their analogous compounds should crystallize together. NOTE.-Since this paper was communicated to the Society Mr.Chapman has kindly drawn my attention to the fact that a mineral nearly if not quite identical with phospho-cerite was discovered and analysed by Wohler about three years ago. It is thus described in the Rapport Annuel of Berzelius 7e. annee “Wohlcr has found in the compact apatite of Arendal a new mineral to which hc has given the name of C‘ryptolite (CPUTTOS). It occurs principally in the variety called apatite rost! whence it MR. HENRY WATTS ON PHOSPHO-CERITE. is obtained in perfect crystals by dissolving the apatite in nitric acid which leaves undissolved a number of small crystals of various minerals. Among these crystals occur those of cryptolite they are a line in length and are laid parallel to each other side by side.There also occur crystals of magnetic iron ore amphibole and a mineral of a hyacinth-red colour. The crystals of cryptolite may be separated by a pair of forceps. When examined by the microscope they are found to be transparent hexagonal prisms of a wine-yellow colour. Their specific gravity is 4.6. ‘‘ Concentrated sulphuric acid decomposes them the whole being reduced to a dry earthy mass. By analysis they are found to contain Ceric oxide . . 73.70 Ferrous oxide . . 1.51 Phosphoric acid . . 27-37 ~ ~~~ 102.58 ‘‘The excess of this analysis is due to the oxygen of the ceric oxide the mineral itself containing cerous oxide. The result of the analysis agrees sufficiently with the formula Ce P to justify the admission that the mineral is formed almost wholly of phosphate of ceric oxide.“The hyacinth-red mineral likewise contained cerium ; but the quantity of it was too small for analysis.” Such is Wohler’s account. The quantity of cerous oxide con-tained in the 73.70of ceric oxide is 68-62; and the proportions of that oxide and phosphoric acid in 100 parts (leaving out the iron) are as 71.5 28.5. These quantities do not agree so closely with the formula 3 MO PO, as those found in my own analysis; still there can be but little doubt that Wohler’s mineral is really a tribasic phosphate and therefore identical in chemical composition with phospho-cerite. The specific gravities of the two minerals are like- wise nearly the same.But the crystalline forms are totally incom- patible; for the hexagonal prism can never occur as a modification of forms belonging to the square prismatic system; and as Wohler’s crystals were large enough to be picked out with the forceps it is scarcely probable that he can have mistaken their crystalline form. For these reasons I do not think it necessary to alter the name which I have given to the mineral obtained from the cobalt ore. 140 MR. HENRY WATTS ON CEKTUM &C. SEPARATION OF CERIUM LANTHANUM AND DIDYMIUM. As the methods of obtaining these substances in a state of purity are not very generally known and as far as I am aware are not fully described in any English work I here subjoin a sketch of the several methods hitherto devised adding such observations as my own experience has suggested.I shall first speak of the methods of separating cerium from lanthanum and didymium together and afterwards of the separation of lanthanum and didymium from each other. I. The separation of cerium from lanthanum and didymium depends upon this circumstance that cerium forms two oxides the yrotoxide or cero%s oxide and thc sesyuioxide or ceric oxide; the latter of which is nearly insoluble in weak acids; whereas lanthanum and didymium appear to be susceptible of only one degree of oxidation and their oxides are easily soluble in dilute acids. On this principle is founded the first mode of separation devised by &losander,* to whom we are indebted for the discovery of lanthanum and didymium.This method consists in converting the mixed oxides of the three metals into chlorides precipitating with a large excess of caustic potash and subjecting the precipitate suspended in the liquid to the action of a stream of chlorine gas. The oxides of lanthanum and didymium then dissolve in the mixture of chloride of potassium hypochlorite of potash and excess of hypochlorous acid produced while the cerium is peroxidized and remains undissolved. The precipitate first assumes a violet colour then becomes yellow and ultimately of a deep orange colour. When this has taken place the liquid is found to be completely saturated with chlorine and has acquired a yellow colour. The whole is then to be set aside for four and twenty hours in a close vessel and afterwards the liquid separated by filtration from the insoluble ceric oxide and treated with excess of caustic potash to precipitate the oxides of lanthanum and didy- mium.Such is the method by which &losander first effected the separation of these oxides. He says that the ceric oxide thus obtained is quite free from lanthanum and didymium; but that the super- natant liquid in addition to the oxides of those metals likewise contains a small quantity of cerium for the complete removal of whit the whole process must be repeated three or four times. In these respects my own observations do not quite agree with those * Philosaphical MagaLine vol. XXVIII. p. 241. MR. HENRY WATTS ON CERIUM &C. of Mosander. I find that the quantity of oxide of cerium dissolved in the chlorine liquid is very small and is completely precipitated by boiling the solution till it loses its yellow colour a salmon-coloured precipitate then separates which is the oxide of cerium.If the boiling be then stopped the liquid filtered and the oxides of lanthanum and didymium precipitated by caustic potash the pre- cipitate thus obtained is quite free from cerium; for on being again subjected to the chlorine process it dissolves completely without any deposition of oxide of cerium. On the other hand I have always found that the ceric oxide produced by the first application of the above process retains considerable quantities of the other oxides and that these can only be separated by repeating the process several times.I find it better therefore instead of leaving the liquid after saturation to stand in contact with the precipitate for several hours to pour it off fill up the vessel with fresh caustic potash again pass chlorine through the liquid till it is saturated and repeat this treatment till the yellow liquid after being boiled till its colour disappears and then filtered no longer gives a precipitate with caustic potash. When this point is attained the ceric oxide niay be considered perfectly free from lanthanum and didymium. It retains however considerable quantities of hypochlorous acid and salts of potash. To free it from these Mosander digests it at a gentle heat in a solution of potash which removes the hypochlorous acid and then dissolves out the potash by dilute nitric acid.The eeric oxide thus purified is then washed and ignited. I find however that a much more expeditious mode of purification is to dissolve the yellow ceric oxide in boiling hydrochloric acid continuing the boiling till chlorine is no longer evolved and then precipitate the cerium by oxalate of ammonia. The precipitate of oxalate of cerium thus formed is a heavy crystalline powder which when collected on a filter may be washed with the greatest facility; and when subsequently dried and ignited yields pure ceric oxide of a delicate cinnamon colour. This mode of separating cerium from the allied metals is long and tedious; but the result is certain and the separa- tion complete. Another mode of separating cerium from lanthanum and didy- mium also discovered by Mosander is to digest the mixed oxides in very dilute nitric acid.The dark red-brown substance obtained by igniting a mixture of the oxalates carbonates or protoxides of the the three metals (for the sake of distinction I shall call it the crude oxide of cerium) consists of ceric oxide mixed with the oxides and carbonates of lanthanum and didymium. It dissolves readily in MR. HENRY WATTS ON CERIUM $C. hot strong nitric acid. The solution which is of a beautiful deep orange colour and acquires by concentration the consistence of a thick syrup leaves when evaporated to dryness a yellow gummy residue of nitrate of ceric oxide together with the nitrates of the other two oxides.When this substance is ignited at a temperature sufficient to expel the nitric acid it leaves a residue nearly if not quite identical with the crude oxide of cerium before treatment with nitric acid but of a much lighter colour and much less soluble in acids. These differences of colour and solubility appear to be nothing but a difference of aggregation. Now when this crude oxide of cerium modified as above by treatment with nitric acid and subse- quent ignition is digested for several hours in very dilute nitric acid-about 1 part of acid in 100 parts of water the lanthanum and didymiuni are dissolved and the cerium left behind. One disestion in nitric acid is not however sufficient to remove the whole of the lanthanum and didymium. The liquid must be poured off after a while and fresh acid supplied; and this process must be repeated till the acid liquid after remaining for some time in contact with the ceric oxide gives no precipitate with oxalate of ammonia.The ceric oxide is then left behind of a pure and beautiful cinnamon colour. This process appears from description to be much easier than that first described. It is however liable to certain inconveniencies. (1.) The oxide of cerium when digested in the acid liquid and more particularly if subsequently washed with water becomes so minutely divided that it diffuses itself through the liquid and will not separate for days; and if an attempt be made to filter the liquid the solid matter first runs through the filter and then com-pletely stops it up.This inconvenience may be obviated to a considerable extent by warming the liquid or rather by keeping it in a warm place during the whole time of digestion. But there is always a considerable difficulty in obtaining a clear solution and in getting the ceric oxide completely free from the soluble matter. (2.) The separation is not always complete. The nitric acid gene- rally dissolves a small quantity of cerium. To separate this the acid solution must be evaporated to dryness the residue ignited and again digested in weak nitric acid this process often requires to be repeated three or four times. When the ignited residue dissolves completely in cold dilute nitric acid the oxides con-tained in the solution may be precipitated by caustic potash or the solution evaporated to dryness and the residue ignited to expel nitric acid.To make quite sure of the absence of cerium a small portion should be tested by the chlorine process above described if MR. HENRY WATTS ON CERIUM &C. any cerium should still be found remaining it is best to treat the whole by that process. When the oxide of cerium has been freed as much as possible from lanthanum and didymium a small portion of it should be boiled in strong hydrochloric acid. If pure scarcely a trace will dissolve with a barely perceptible evolution of chlorine. A solution may however be obtained by the aid of alcohol which deoxidizes the ceric oxide and reduces it to a state of cerous oxide the acid then dissolves it. The solution thus obtained should be tried by the chlorine process to ascertain if any didymium be left behind.If so the ceric oxide may be digested for a while in moderately dilute hydrochloric acid which will dissolve the remainder of the hdymium. The nitric acid is sure to remove the whole of the lanthanum. It is remarkable that the ceric oxide obtained by this process is always of a lighter colour than that obtained by the process first described. Even if it be dissolved in acid precipitated as an oxalate and the oxalate again converted into ceric oxide by ignition the light colour is retained. I was at first inclined to attribute this difference to the greater purity of the ceric oxide obtained by the latter process but I have carefully tested that obtained by the chlorine process by digesting it for a long time in hydrochloric acid and have not been able to discover a trace of didymium in it.I attribute the difference of colour merely to a difference of aggregation I have already observed that the crude oxide of cerium acquires a lighter colour by mere solution in nitric acid evaporation to dryness and ignition. A modification of the preceding process has been suggested by Berzelius. I shall notice it in speaking of the separation of lanthanum and didymium. A method of separating cerium from didymium by means of valerianic acid has been devised by L. L. Buonaparte.* It is thus described by Berze1ius.t ‘‘The hydrated oxides are precipitated by a caustic alkali and the cerous oxide converted into ceric oxide.The whole is then dissolved in nitric acid-the excess of acid driven off by evaporation at a gentle heat-the residue mixed with a very small quantity of water and a saturated solution of valerianic acid added drop by drop as long as any precipitate forms. This pre- cipitate is the valerianate of ceric oxide; valerianate of didymium remains in solution.” It is not stated whether this reagent will separate lanthanum from either of the other oxides but there is every probability that its action on lanthanum will be the same as on didymium. I have not tried the method its I do not think that * Comptes rendus t. XVI p. 1008. 1-TraiG IT 752. MR. HENRY WATTS ON CERIUM &C it can ever be made available excepting on a very small scalc on account of the great trouble of preparing the acid.Besides we have easier methods of separating cerium from the other two metals. 11. Separation of Lanthnnum and Didymium.-A solution of these substances free from cerium having been obtained by either of the preceding processes they may be precipitated either as hydrated oxides by means of caustic potash or as oxalates by the addition of oxalate of ammonia. I prefer the latter method because the filtration and washing are so much more expeditious than with the former. The oxalates are then to be converted into carbonates by ignition and the carbonates dissolved in dilute sulphuric acid. The separation of the two metals depends upon the different degrees of solubility of their sulphates ; and the mode of effecting it is different according as the lanthanum or the didymiuni is in greater quantity.This may be known by the colour of the solution. When the didymium is in excess the solution has a decided pink colour even when dilute; but when the quantity of' that metal is but small the liquid is colourless when dilute and does not assume a pink colour till highly concentrated. When the lanthanum is in excess Mosander recommends the following process. The solution containing the mixed sulphates is to be evaporated to dryness and the residue ignited to expel the water of crystallization and the excess of sulphuric acid. The anhydrous sulphates are then to be dissolved in rather less than six times their weight of water at a temperature of 36O or 37O Fah.the powder being added by small portions at a time and the vessel containing the liquid being surrounded by ice-cold water to prevent the rise of temperature consequent ou the combination of the an- hydrous sulphates with water. If this precaution be not taken and the temperature of the liquid consequently rise above 48O Fah. crystallization commences and rapidly extends throughout the whole mass of liquid. If however the water be properly cooled the anhydrous sulphates dissolve completely. A solution having been thus obtained it is to be gradually raised by a water-bath to a temperature of rather more than 103O Fah. when the sulphate of lanthanum will crystallize out contaminated however with sulphate of didymium which gives it a rose colour.To purify it completely from didymium Mosander directs that it be again rendered anhy- drous redissolved in ice-cold water &c. the whole process requiring to be repeated ten or twelve times before the sulphate of lanthanum is obtained perfectly pure. I have made three or four trials of this MR HENRY WATTS ON CERIUM &C. process with all possible care but have never succeeded in getting the sulphate of laahanurn to crystallize out in the manner above described. Probably the substance on which I have operated is richer in didymium than those on which Mosander's experiments were made. At all events the process as may be seen from the preceding description is excessively long and troublesome ; and I believe that a pure salt of lanthanum may in all cases be more readily obtained by that which I am about to describe.The sulphates of lanthanum and didymium have this remarkable relation that though the sulphate of lanthanum is less soluble than the sulphate of didymiurn in a neutral solution yet from an acid solution the sulphate of didymium crystallizes out first. Accordingly a pure salt of didymium is easily obtained as follows. A solution of the mixed sulphates containing excess of sulphate of didymium is strongly acidulated with sulphuric acid and left for two or three days in a warm place. Two sorts of crystals then collect at the bottom of the basin 1. Large rose-coloured rhombohedral crystals modified with numerous secondary faces. 2. Slender prismatic violet-coloured crystals which adhere to the sides of the vessels.The latter consist of the two sulphates mixed; the former are sulphate of didymium these are to be selected from the rest separated as much as possible from adhering sulphate of lanthanum by rapidly washing them with hot water and finally purified by recrys- tallization. This is also Mosander's process. I have invariably found it successful. But further-I find that bv redissolving the prismatic violet crystals above spoken of-mixing the solution with the mother-liquid and again subjecting it to slow evaporation though no more large crystals of didyrnium-salt are obtained the liquid yields rhombohedral crystals of a violet colour ;and by taking these out evaporating the mother-liquor still further and repeating these operations three or four times the solution at length becomes perfectly colourless and when evaporated to dryness yields a colour-less residue of sulphate of lanthanum.The solution in this state likewise yields perfectly colourless precipitates with alkalis and alkaline carbonates and also with oxalic acid. This is the only method by which I have yet succeeded in obtaining a pure salt of lanthanum. It is sufficiently tedious but the result is satis-factory. I have already spoken of a process suggested by Berzelius* for separating lanthanum and didymium it is as follows. The crude * Trait6 de Chimie 5e. Ed,11. 752. VOL. 11.-NO. 1'1. L NR. HENRY WATTS ON CERIUM &C. oxide of cerium after solution in nitric acid and subsequent ignition is digested for a while in very dilute nitric acid (1part of acid in 100 of water) the solution is then poured off and the residue digested in dilute hydrochloric acid.The nitric acid removes nearly all the lanthanum together with small quantities of didymium and cerium and the hydrochloric acid dissolves out all or nearly all the didymium together with the remaining portion of lanthanum and more or less of cerium. The cerium may be removed from both solutions by evaporating to dryness and redigesting in dilute acid repeating the process till no insoluble residue remains-or else by the chlorine process. The nitric acid solution always contains more or less didymium sometimes a considerable quantity the longer the digestion is continued the greater is the quantity of didymium dissolved.It may however be completely removed by converting the salts into sulphates and crystallizing out the sulphate of didy- mium from an acid solution. From the hydrochloric acid solution a pure salt of didymium may readily be obtained by precipitating with caustic potash dissolving the precipitate in excess of sulphuric acid and crystallizing by spontaneous evaporation as above described. The ceric oxide also after digestion in hydrochloric acid is almost sure to be pure. On the whole this process affords a ready means of obtaining salts of lanthanum and didyrnium nearly pure if absolute purity be desired they must be farther treated by the methods above indicated.The salts of lanthanum and didymium are distinguished from one another by marked characters. All the salts of didymium are coloured some being pink or rose-coloured and others violet. The sulphate is rose-coloured so also is the nitrate the solution of the nitrate however when highly concentrated is violet-blue by reflected light. The hydrated oxide and the carbonates are violet; so likewise is the oxalate. When either the oxalate the carbonate or the hydrated oxide is ignited it yields the anhydrous oxide which is of a dark brown colour. It is this oxide which gives the dark red-brown tint to the crude oxide of cerium; it is readily soluble in dilute acids; when exposed to the air it absorbs carbonic acid. All the salts of lanthanum are white.The oxalate when ignited first turns black from the separation of carbon; and when this is burnt away perfectly white carbonate of lanthanum is left. This when more strongly ignited,-especially in an open vessel-. is con-verted into a light brown substance which is the anhydrous oxide. In Mosander’s memoir this oxide is said to be nearly white; and the slight brown colour which it has is attributed to the presence of a MR. HENRY WATTS ON CERIUM &C. minute quantity of didymium. This however I cannot but regard as doubtful; for I can perceive no difference of colour between the anhydrous oxide obtained by igniting perfectly white carbonate of lanthanum and that produced from carbonate which I know to be slightly contaminated with didymium.When carbonate of lan-thanum in small lumps is ignited the surface of the lumps turns brown while the inner portions remain perfectly white ; when carbonate of didymium is similarly treated the whole becomes dark brown in a very short time. Anhydrous oxide of lanthanum attracts carbonic acid from the air more rapidly than oxide of didymium the hydrated oxide which is perfectly white absorbs carbonic acid so rapidly that when washed on a filter it is wholly converted into carbonate before the washing is complete. It will be seen from the preceding observations that the main difficulty in all these processes is to obtain a pure salt of lanthanum. It is difficult even to ascertain when that result is attained; the only test is the perfect whiteness of the salts the least trace of didymium imparts a violet colour to a concentrated solution which a practised eye can readily detect.I was for a long time led away by the expectation of obtaining anhydrous oxide of lanthanum perfectly white and have spent a great deal of time and labour in endeavouring to get rid of a colour which I am now inclined to believe is essential to the substance. Since writing the above I have found that the oxides of lanthanum and didymium may be completely separated from oxide of cerium by boiling the crude oxide in solution of sal-ammoniac after having dissolved the oxide in nitric acid and driven off the acid by ignition as already described. The ceric oxide thus obtained is of a delicate fawn colour. I have not yet been able to examine the results minutely but the portions first dissolved appear to contain but a very small quantity of didymium.This being the case it is probable that by using a weak solution of sal-ammoniac and properly fractioning the products a pure salt of lanthanum may be at once obtained. At all events this process as far as I have examined it seems more likely to yield good results than any that I have pre- viously tried. I shall pursue this investigation and hope soon to have more definite results to lay before the Society.

ISSN:1743-6893    

DOI:10.1039/QJ8500200131

出版商:RSC    

年代:1850

数据来源: RSC

摘要:

DK. LEESON ON ISOMORPHISM &C. XV.-On Isomorphism +. and on a simple Zaw governing all crystalline forms by H. B.LEESON, M.D. MY former papers were more especially intended to conduce to a correct reading of crystalline forms and to show the relationship which all crystals possess to certain lines of direction termed gubernatorial axes such axes not being arbitrarily chosen but coinciding with the directions of the aggregating forces magnetic and electric and evidenced by the state of tension existing in the interior of the crystals as exhibited when such crystals are examined by polarized light. I am the more anxious to impress upon all those advancing doctrines having reference to crystalline form the necessity of a correct understanding of the crystals on which their observations are based because I observe in numerous papers on Isomorphism Dimorphism &c.that forms have been considered primary although onIy secondary modifications ; and that substances have been ranked as dimorphous although in fact only crystallized in different varieties of the same system or class. If Isomorphism as the name would imply had reference simply to the same external configuration then all substances would be polymorphous ; for although only one form may have hitherto been observed in any particular substance still the instances are so numerous in which the same substance (as for instance fluor spar sulphate of barytes or carbonate of lime,) does crystallize in a variety of forms that judging from analogy we have reason to believe every substance may be similarly varied; or to convey our meaning in other words; that each substance may crystallize in uniaxial biaxial and triaxial forms such forms being still further varied by imperfect or defective development elongation and composition for the understanding of which I must refer to my former papers as printed in the Memoirs of the Chemical Society.The term isomorphous is now then generally employed with reference only to the system in which a substance is supposed to crystal- lize; and such system or class must be determined by the position and length of the gubernatorial axes. Perhaps I may be excused for suggesting that the term omo-axed or sirnil-axed would better convey the idea intended and prevent that misconception which evidently exists in the minds of some observers.Since I first noticed the similarity of the series of forms occurring in each class I have been enabled very considerably to enlarge my collection by specimens exhibiting a regular gradation of such forms. This has enabled me to apply the goniometer formerly described DR. LEESON ON ISOMORPHISM &C. to the messurement of the inclination of edges-as well as of planes in a very extensive series of crystals. Thus it is that I have been led to observe a very simple relation indicating the law by which so far as my own observations extend every variety of crystalline form seems to be engendered.* Premising that the law itself is masked (as explained in my former papers) by the unequal development of particular planes; that such unequal development sometimes occasions the defect of certain planes and that by elongation or combination of separate forms the external aspect of a crystal may be still further complicated I proceed to enunciate the principle according to which as I believe all perfect forms are produced.Of course in examining a particular crystal those planes must be selected which belong to the same simple form then such form must be considered as it would exist if all the planes were equally developed and any defective planes supplied all this will be the more readily accomplished when the method of Nature’s proceeding and the series of forms is fully understood. To enunciate then the principle.The perfect simple forms constitute a series c0mmencin.y ; First with the uniaxial form and subsequently composed of six pyramids of four or eight sides placed oiie at each extremity of the three gubernatorial axes. Such pyramids succeeding each other by a similar and regular gradation WHATEVER BE THE SYSTEM or disposition and normal length of the gubernatorial axes. The series then may be considered as composed FIRST,of the uniaxial form. A six-sided parallelopiped described in my former papers as produced by a plane placed on each extremity of the gubernatorial axes so as to be parallel to the other two axes. The planes of this form may be considered as the lower limit or zero in height of the biaxialf- pyramids. SECONDLY, of alternate triaxial and biaxial forms consisting each * In my former papers I have already shewn that uniformity in the measurement of the inclination of planes is far from constant and that the mathematical accuracy supposed to be attainable is not to be expected.My own goniometer and the microscope have still further convinced me that planes apparently perfect and brilliant to the naked eye are full of inequalities ; and I believe that in fluor want of attention thereto and of microscopic examination has caused inclinations to be taken for planes which really consisted of step-like diminutions whilst in that substance as in bismnth and other metals forms have been considered rhombic resulting merely from the unequal deposition or subsequent removal (by solution or otherwise) of lamina on one or more edges of the crystal.t By referring to my preceding papers it will be understood that the term ‘‘biaxial” means that the planes cut two of the gubernatorial axes and are parallel to the third axis whilst ‘‘ triaxial” planes cut all three axes. DR. LEESON ON ISOMORPHISM &C. of six four-sided pyramids replacing or surmounting as it were the uniaxial planes; and placed on each extremity of the gubernatorial axes in such a manner as that a line joining the apices of the opposite pyramids corresponds to the gubernatorial axis ;whilst the four sides of each pyramid are parallel in the biaxial forms to the four edges of the uniaxial plane they respectively surmount ;and in the triaxial forms to the diagonals of such plane.These forms succeed each other in a series produced by a continual replacement of the four lateral edges of the pyramid by planes; so that each succeeding or preceding pyramid differs or revolves as it were 45O on theuniaxial plane. And THIRDLY, of a series of triaxial forms composed of six eight- sided pyramids produced as it were by a duplicature or repetition of the pyramids of the triaxial forms in the preceding or second series. Each eight-sided pyramid consisting of planes joining the four lateral edges of a pyramid of one of the triaxial forms in the preceding series with the four lateral edges of another equal and similar pyramid placed in the reverse or biaxial direction so that the bases of the two pyramids thus joined together differ from each other 45O.The primary triaxial form may be considered as the first pyramid of the series or point of departure; from which by the continual replacement of edges by planes the most usual and descending series of pyramids of lower height is produced; whilst by replacement of planes by edges an ascending series of more acute pyramids may be obtained. The ascending series will necessarily consist of only two pyramids joined base to base otherwise re-entering angles as subsequently explained would be produced which is inconsistent with a perfeet form. Ae an illustration of the principle I will describe the series as occurring in the regular or as I term it the rectangular equiaxial system as that in which the succession may be most easily comprehended; but I hope it will be fully understood that the same series exists in each of the other systems and that I possess numerous specimens to substantiate such position particularly in the oolique and right oblique classes; figures of which I am preparing for publication in which the planes belonging to each member of the series will be designated by a particular colour so as to exhibit at one glance the various perfect forms entering into the composition of any particular crystal.To describe then the series as occurring in the regular system. The figures referred to being those given with my former papers. FiasT.-Primary uniaxial form Cube Fig. 7,Pi. VII. SECOND.-P~~WUW~ triaxial form Octahedron Fig.7 consisting DH. LEESON ON ISOhlORPHISM &C. of six four-sided pyramids placed diagonally on the faces of the cube so as to bisect the four edges of each face. The height of the pyramid being such that the planes of the three pyramids,/ur- rounding each corner of the cube coincide in one plane; thus each plane of the octahedron may be considered as composed of the planes of three separate pyramids and corresponds to the lower limit or zero of the three-sided pyramid to be observed in each SUC-ceeding triaxial form the solid angles of the cube being the upper limit or zero of height of the three-sided pyramid. Third.-Primary biaxial form Rhomboidal dodecahedron Fig. 8. By replacing the twelve edges of the octahedron by planes the rhom- boidal dodecahedron is produced and it will be readily observed in Fig 8 that it consists of six four-sided pyramids placed with their sides parallel to the edges of the cube the height of the pyramid being such that the planes of the two pyramids adjacent to the same edge coincide and thus form one plane.If the pyramid were of lower height as in the succeeding biaxial forms the planes would as it were double over the edge and thus give rise to twenty-four instead of twelve planes. If the pyramid were of greater height the angle across the edge would be a re-entering angle. Hence this hrm is the limit of the height of the pyramid in the biaxial forms. POURTH.-&COTZ~ triaxial form Trapezohedron Fig. 21 P1. X. This form results from a replacement of the edges of the rhomboidal dodecahedron by planes and may be easily observed to consist of six four-sided pyramids the sides of which are parallel to the diagonals of the sides of the cube; but in consequence of the manner in which the planes necessarily intersect each other at their bases the planes themselves lose their triangular outline becoming in fact trapezoidal and thus obscuring the pyramidal nature of the form.The height of the pyramid being less than in the primary triaxial form originates a three-sided pyramid corresponding to each face of the octahedron and the form might thus be considered as composed of eight three-sided pyramids. The solid angles of the cube or uniaxial form being the upper limit or zero in height of these three- sided pyramids.A line joining the opposite pyramids corresponds of course to a diagonal of the uniaxial form. FIFTH.-&?cOnd biaxiul form Pyramidal hexahedron Fig. 7 P1. X. produced by planes replacing the edges of the last form and evidently consisting of six four-sided pyramids of lower height than those of the primary biaxial form and therefore doubling over the edges of the uniaxial form as already explained. This doubling originate8 a six-sided pyramid corresponding to each face of the octahedron or 152 DR. LEESON ON ISOMORPHISM &C. primary triaxial form. Hence the diagonals of the uniaxial form join the apices of the opposite six-sided pyramids. SIXTH.-T~~~~ Triaxialform a more obtuse trapezohedron. SEvE"rH.-!ird biaxial form a more obtuse pyramidal hexa- hedron.EZGHTH.-FOU& triaxial form a trapezohedron still more obtuse. NINTH.-F$~ biaxial form a pyramidal hexahedron with still flatter pyramids. Unless in fluor what I consider as step like strk be considered planes I have no specimens carrying this second series beyond the fifth biaxial form. THIRD SERIES.-F~~S~, a duplicature of the primary triaxial form or octahedron. The Triaxisoctahedron Fig. 24 P1. VIII. formed of planes joining the edges of the primary triaxial form or octahedron with those of another equal and similar octahedron resolved 45O thus forming a figure compounded of six eight-sided pyramids placed on the extremities of the gubernatorial axes or of eight three-sided pyramids placed on the faces of the octahedron.The line joining thc apices of the opposite three-sided pyramids corresponds to the diagonals of the uniaxial form. These three-sided pyramids are it will be observed in reverse position to those belonging to the trape- zohedron. Compare Fig. 24 P1. VIII. with Fig. 7 P1. VII Second form a duplicature of the second triaxial form or trape-zohedron producing the Tetraconta Octahedron Fig. 21 P1. VIIL composed of 48 planes joining the four lateral edges of the six pyramids of the second triaxial form with the four lateral edges of six other equal and similar pyramids placed in the reverse or biaxial direction each plane of the cube or primary uniaxial form is thus surmounted or replaced by an eight-sided pyramid and each solid angle of the cube or face of the octahedron by a six-sided pyramid.Third form a Tetracontahedron derived from a duplicature of the third triaxial form and hence more obtuse. Fourth a still more obtuse Tetracontahedron derived from the fourth triaxial form. Beyond this point I do not possess nor have I met with any specimen. Thus it is evident that if one number of the series can be fairly made out all the others may be deduced from it; and I have greatly assisted my labours by preparing and keeping by me a table of the successive angles of inclination assuming 78O 20' as the most frequently occurring acute angle of the oblique uniaxial forms. In conclusion I would refer to a few circumstances which have tended as I believe to erroneous conclusions.DR. LEESON OM ISOMORPHISM &C. First too much reliance on the perfection of planes which on examination by the microscope would have been found imperfect. Next assigning a primary position to planes of a secondary character. I have already sufficiently indicated in my former paper many instances of this description. 1 have in my collection perfect rhomboids of fluor spar pro- duced by the defect of two p€anes of the octahedron as indicated in Fig. 23 plate XII.; and yet no one has hitherto ventured to pronounce fluor dimorphous. Again I have cubes of fluor apparently rhombic from the unequal deposition of laminz before referred to and yet similar discrepancies in bismuth and antimony have induced some to consider such crystals as not belonging to the regular system.But again since by defect of planes consequent on the undue development of the planes of any two opposite four-sided pyramids every form may become octahedral. It is evident that the apparent proportional length of the axes in different supposed octahedra of the same substance may be greatly varied and thus a substance actually belonging to the regular system may be referred to the pyramidal merely in consequence of the octahedron examined not being the primary triaxial variety but a portion of another form. I have crystals both of copper and of silver illus- trating this position; and which if they had occurred to other observers would I have no doubt have induced them to class these substances as like tin similarly circumstanced dimorphous.Cleavage in such cases would evidently afford no assistance ; and here again I may observe too much reliance must not be placed on the coincidence of clcavage planes with those of the uniaxial form. In fluor it is well known the cleavage planes correspond with the primary triaxial planes; and I believe that in the right oblique system they frequently coincide with the primary biaxial planes. Lastly I would caution persons not to consider crystals as pseudomorphous merely because they are of unusual occurrence amongst the specimens of the substance. If there is no reason to suppose the crystals have been actually moulded in the matrix of some other crystal the term is not appropriate.I have primary uniaxial and triaxial specimens of quartz which others would term pseudomorphous but which I believe have not been formed in any matrix and are only SO termed because persons have not been accustomed to believe in the existence of such forms. MR. CHAPMAN ON March 19 1849. The President in the Chair. The following presents were announced “Memoirs upon Natural History,” collected by W. Haidinger and published by subscription and ‘‘Reports upon the Communications of the Friends of Natural Science in Vienna,” from W. Haidinger. Messrs. C. F. Birnaud G. Simpson E. Packard and R. Prosser were elected members of the Society. The following papers were read Analysisof Berlin Porcelain by MR.WILLIAM WILSON,Student in the Royal College of Chemistry.-The specimen analysed was taken from an evaporating dish and the quantities of the different ingredients were estimated by the usual analytical processes.The specimen as shown by the composition detailed below was richer in silica and protoxide of iron than is usually the case while there is a deficiency in alumina and potash. Silicic acid . . 71.34 Alumina . . 23.763 Protoxide of iron . .. 1.743 Lime ..... . 0.5686 Magnesia ... . 0.1923 Potash .... 2.001

ISSN:1743-6893    

DOI:10.1039/QJ8500200148

出版商:RSC    

年代:1850

数据来源: RSC

摘要:

MR. CHAPMAN ON XVL-Note on the Phospho-cerite of Mr. Watts. BYEDWARD ESQ. J. CHAPMAN The object of this communication is to point out the apparent identity existing between the Phospho-cerite so ably analysed by Mr. Watte and a mineral discovered by Wohler about three years ago and named by him Cryptoh from the Greek word K~VTTOS concealed. This substance is contained with several other minerals in the rosecoloured apatite of Arendal in Norway and is obtained accord- ing to Wohler in very minute hexagonal crystals of a wine-yellow colour by dissolving the apatite in nitric acid. It is associated with microscopic crystals of magnetic-iron-ore hornblende and an unknown substance of a hyacinth-red colour containing cerium. The specific gravity of the cryptolite was found to equal 4.6 and its analysis furnished Phosphoric acid .. . 27-37 Peroxide of cerium . . 73.70 Protoxide of iron . . . 1.51 Total . . 102.58 THE PHOSPHO-CERITE OF MR. WATTS. The excess arises from the protoxide of cerium contained in the mineral being converted by ignition into peroxide. If we calculate these results after the atomic weight of the mixed metals cerium lanthanum and didymium the cryptolite may be considered a tribasic phosphate of the protoxide of cerium (3 CeO PO6) and as such identical in composition with the phospho-cerite of Mr. Watts allow- ing the cerium of Wohler’s analysis to be a mixture of the three metals. Having stated to Mr. Watts my intention of offering afew remarks on the existing phosphates of these bases in reference to his phospho- cerite that gentleman kindly presented me with a small quantity of the mineral for examination.It occurs when separated from the Dannemora cobalt by nitric acid in the form of a fine powder consisting of crystalline grains partly of a pale sulphur-yellow colour and partly colourless; possessing a degree of hardness equal to 5.0 5.5 and exhibiting in an eminent degree when examined by the microscope a peculiar vitreo-resinous or adaman tine lustre. The specific gravity as determined by Mr. Watts is 4-78. The greater number of the grains have no definite form their edges appearing more or less rounded; but here and there may be recog- nised although by no means distinctly certain crystals of which after a careful investigation I have been able to make out the three following forms first a more or less acute octahedron fig.1; FIG. 1. FIG. 2. FIG. 3. FIG. 4. secondly a combination of that form with a four-sided prism fig. 2 ; and thirdly an octahedron with its apices replaced by apparently a single plane fig. 3. Figures 2 and 3 shew that the octahedron is not a regular one as all the edges in the one case and the angles in the other are not modified simultaneously; and from the general character of the crystals I have been led to attribute them to the dimetric or square prismatic system. It must be confessed however that they do not present any visible modifications by which this deter- VOL. 11.-NO. VI. L3 156 MR.CHAPMAN ON THE PHOSPHO-CERITE OF MR. WATTS. mination can be rendered certain and from their extreme minuteness it is of course impossible to ascertain by measurement whether the prism be a right one or not. These forms therefore do not exclude the mineral from either the trimetric or monoclinic systems (pris- matic and oblique-prismatic systems of Mohs) but they show incon- testibly that it cannot belong to the hexagonal or rhombohedra1 group as the prisms of that system of crystallization cannot possess four lateral planes. In this lies the principal difference between the phospho-cerite and Wohler’s cryptolite. If the crystalline form of the latter belong to the hexagonal system the tribasic phosphate of protoxide of cerium must be dimorphous; but on the contrary if it belong to the trimetric or monoclinic systems the hexagonal crystals of Wohler are easily accounted for by the truncation of either the obtuse or acute lateral edges of the primary giving rise to the two planes h1 or g1 (in the nomenclature of Levy and Dufrbnoy) and thus forming a six-sided prism.I should here state also that on my first examina- tion of the minute grains of the phospho-cerite I fancied that T detected hexagonal prisms amongst them ;but I found afterwards that this proceeded from my having obtained a strong outline in relief of the little prismatic crystals as they rested upon one of their lateral planes. If we take the outline of figure 2 for instance it will present an hexagonal form appearing thus when viewed by transmitted light like the base of a six-sided prism.See fig. 4. If the phospho-cerite really belong to the dimetric system it may be considered isomorphous with the tribasic phosphate of Yttria the phosphyttrite of Berzelius; and I may mention as a curious coinci- dence that thi8 latter mineral has. lately been found associated like thephospho-c&e with mme of the SWG&& cobalt ores Allowing the phospho-cerite and the cryptolite to be identical the mineral kingdom would appear to possess two distinct phosphates of cerium one of the protoxide and one of the peroxide the mwzite or mengite of Mr Brooke; this latter mineral causing the evolution of chlorine when decomposed by hydrochloric acid. Considering however the fact that the amount of phosphoric acid in these minerals from four different analyses by Mr.Watts Wohler Erd-mann and Hermann does not exhibit a difference of 1 per cent and that the protoxide of cerium is very readily converted by atmospheric causes even into the peroxide might we not be tempted to regard the monazite as an altered phospho-cerite and to look upon the red grains found by Wohler with the cryptolite as forming a tran- sition from one to the other. The monazite it is true; crystallizes in DR. KOLBE’S RESEARCHES ON THE ELECTROLYSIS ETC. 157 the monoclinic or oblique-prismatic system but this I have shewn is not incompatible with the forms assumed by the phospho-cerite and the more so as the angle MJ M of the monazite 92O 30’,closely approaches a right angle. Exposed to the blow- pipe the phospho-cerite vitrifies partially on the edges and surface tinging the flame at the same time slightly green. With the usual blow-pipe re-agents it presents the reactions of cerium imparting however to the borax and phosphate of soda glasses when cold a pale violet-blue tint either due to the presence of didymium or to an admixture of a minute portion of the cobalt ore. With boracic acid and soft iron-wire it produces a brittle globule of phosphuret of iron.

ISSN:1743-6893    

DOI:10.1039/QJ8500200154

出版商:RSC    

年代:1850

数据来源: RSC

摘要:

DR. KOLBE’S RESEARCHES ON THE ELECTROLYSIS ETC. 157 XVIL-Researches on the Electrolysis of Organic Compounds. BY DR. H. KOLBE. COMMUNICATED BY DR. A. W.HOFMANN. The following investigation has chiefly arisen from some former observations* respecting the transformations of chloro-carbo-hyposul-phuric acid hydrochloric acid and several other substances under the influence of oxygen when liberated in the circuit of the galvanic current.? The facility with which particularly the former acid resisting in the moist way the most powerful oxidizing processes is decomposed under these circumstances appears to point to electrolysed Oxygen as one of the most valuable oxidizing agents which are at the disposal of the chemist. Its application in chemical decompositions acquires additional importance since its intensity may be varied either by concentrating and heating the liquid or by increasing or diminishing the number of elements producing the electrical current.Starting from the hypothesis that acetic acid is a conjugated * Observations on the oxydizing action of oxygen when disengaged by means of voltaic electricity in the “ Memoirs and Proceedings of the Chemical Society,’’ vol. III. p. 285. t In the above cited investigation it was intended to state that in the oxidation of hydrochloric acid by means of the electrical current chloric acid appears at the positive pole even without the presence of an alkali. The sense of the sentence has been seriously altered by a misprint on page 287 line 8 from the top hypochloric having been substituted for fd hydrochloric acid.” The sentence should have been as follows ‘‘I have ascertained that when a voltaic current is passed through hydrochloric and especially when previously mixed with some sulphuric acid free chloric and perchloric acids are formed after the disengagement of a considerable quantity of chlorine.” DR.KOLBE’S RESEARCHES ON compound of oxalic acid and the conjunct methyl I considered it under these circumstances not at all improbable that electrolysis might effect a separation of its conjugated constituents and that in consequence of a simultaneous decomposition of water carbonic acid as a product of the oxidation of oxalic acid might appear at the positive while methyl in combination with hydrogen viz.as marsh- gas would be observed at the negative pole. The decomposition which actually takes place is not in perfect accordance with this supposition as will be seen by the experiments hereafter described. The results obtained however are by no means less interesting and deserve particular attention opening as they do a prospect that the electrolytical decomposition of organic compounds will afford most important disclosures with reference to their chemical constitution. After having made some preliminary experiments with several acids belonging to the acetic acid series the products of the oxidation of valerianic acid appeared particularly suited for minutely following out the course of this decomposition. I therefore consider it convenient first to describe the phenomena attending the decom- position of this acid inasmuch as they form the basis for further experiments.ELECTROLYSIS OF VALERIANIC ACID. Valerianic acid being like acetic acid a bad conductor of elec-tricity I employed in the electrolytical decomposition a concentrated solution of its potash salt prepared by neutralizing carbonate of potash free from chloride mth pure valerianic acid distilling at 175O (347O F.)* The decomposing apparatus Fig.1,t is a glass cylinder 11 inches in height and 23 inches in diameter which may be closed by means of a cork; in this is fastened a cylinder of sheet copper closely ap- proaching the sides of the glass and to which is soldered the copper wire a slightly projecting from the vessel.Within the copper sheet is another cylinder of platinum foil of somewhat smaller diameter terminating in the platinum wire b and prevented contact with * The presence of chloride of potassium gives rise to the formation of secondary chlorinated products requiring more minute investigation. The soda salt cannot be employed with advantage inasmuch as the bicarbonate Thich is formed during the decomposition enfeebles to a great extent the electricaI current interrupting it entirely towards the end of the process. The bicarbonate of potash being more soluble a few crystals only separate during the decomposition. t The plate containing the figures here described not having been sent with the manuscript is unavoidably omitted in this number of the Journal but will appear with the next.THE ELECTROLYSIS OF ORGANIC COMPOUNDS. the copper by a narrow ring of glass placed between the two cylinders at their lower extremities. Both wires as well as the large delivery tube c are cemented perfectly air tight into the cork the tube being of sufficient diameter to admit of emptying and filling the cylinder without inconvenience On passing the electrical current produced by four elements of Bunsen’s zinco-carbon battery through the apparatus iilled to the height c c with a concentrated solution of valerianate of potash the platinum wire b forming the positive pole the negative wire being in connexion with the cylinder of copper the following phe- nomena are observed A lively evolution of gas takes place simul- taneously with the formation of yellowish oily drops possessing an agreeable etherial odour j on agitation with the liquid the oil remains undissolved even on the addition of potash.The remarkably odorous gases which are evolved during the process contain after complete expulsion of air from the apparatus no longer a trace of oxygen and may be ignited without fear of explosion. Carbonic acid and hydrogen however are present in considerable quantities in conjunction with a third gas burning with a highly luminous flame and imparting to the mixture its peculiar odour. After the action of the current had been continued for several hours the stratum of oily liquid on the surface had increased to the height of several lines while the valerianate of potash was almost completely converted into a mixture of carbonate and bicarbonate of potash the latter generally crystallizing towards the end of the operation.With a view of ascertaining at which pole each of these products was liberated I endeavoured to separate the electrodes by means of a porous diaphragm which allowed me to collect separately the substances disengaged at either pole. I employed for this purpose a porous cell of clay into which a small glass tube of nearly equal diameter and open at both ends was fastened air tight by means of a caoutchouc joint. This arrangement containing the platinum foil forming the positive pole and admitting of being closed by a cork furnished with a delivery tube was introduced into the copper cylinder of the decomposing apparatus.Both cylinders were now filled with a solution of the neutral valerianate to the height of about one inch above the caoutchouc joint. It was found that on closing the circuit only hydrogen and free potash were disengaged at the copper pole while all the other products the etherial oil carbonic acid the odorous gas and the DR. KOLBE’S RESEARCHES ON free acid (which in this arrangement prevented the formation of a carbonate,) appeared at the positive pole. VALYL. In the experiments instituted for the preparation * of the etherial oil I preferred removing the product from time to time with a pipette which I introduced through the open glass tube c the process being continued until the solution was entirely exhausted of valerianic acid.The alkaline residue was now again introduced into a porcelain dish and neutralized with pure valerianic acid ;the neutral solution being again repeatedly subjected to the process of electrolysis until a sufficient quantity of oil had been collected. The impure product after repeated agitation with water exhibits the following properties It is miscible with alcohol and ether in all proportions insoluble in water and of lower specific gravity than that liquid. It possesses an agreeable etherial odour. Chloride of calcium is dissolved by it particularly in the cold and hence the slight turbidity which is observed when the clear anhydrous liquid is sub- jected to ebullition. It commenced boiling a few degrees above ZOOo (212O F.) the temperature rapidly rising to 160° (320OF.) and even higher ; the last products possess a penetrating disagreeable odour and differ in a remarkable manner from the liquid which passed over at a lower temperature.The quantity of carbon found in the distillate collected at different temperatures diminishes with the rise of the boiling point decreasing from 80 to 76 per cent. while the amount of oxygen varying between 6 and 10 per cent is found in the inverse proportion. The disagreeably smelling oil distilling towards the end of the operation appears to be formed only by the action of chloride of calcium on the original compound; but even when distilled in vacuo at very low temperatures the distillates collected at different stages of the process exhibit a composition not less variable.It appears that the impure oil is a mixture of at least two sub- stances its deportment with an alcoholic solution of potash affording a powerful argument in favour of this opinion. On boiling a mixture of this oil with an alcoholic solu-tion of potash in a flask connected with the lower extremity of * The decomposing apparatus employed in this and the following experiments was placed in a vessel of water at the temperature of 00 C. The solution of valerianate of potash being moderately heated hardly a trace of the oil is produced the decomposition taking place in an entirely different manner. THE ELECTROLYSIS OF ORGANIC CONPOUNDS. a Liebig’s condenser placed in such a position as continually to return the condensed products to the boiling fluid the following phenomena are observed.Immediately on the application of heat bubbles of a gaseous body are seen to rise possessing the charac- teristic odour of the compound which in the electrolytical decom- position of valerianate of potash accompanies the evolution of hydrogen and carbonic acid hence it appears that this gas which is held in solution by the liquid becomes liberated when heat is applied. In a short time the evolution ceases and the odour of the gas is no longer perceptible; when in a full state of ebullition the oil previously colourless assumes a yellowish tint and becomes slightly turbid while a heavy apparently oily liquid collects at the bottom of the flask which on examination is found to be an aqueous solution of valerianate of potash.To effect complete decomposition of the constituent affected by potash at least half an hour’s ebullition is necessary. On mixing the liquid after boiling with a large excess of water a light etherial oil separates which after standing for some time collects on the surface into a clear transparent layer ;repeatedly washed with fresh portions of water and subsequently dried by chloride of calcium it exhibits a pretty constant boiling point at 108’ (226.4 F.). The fraction distilling at this temperature when subjected to a second rectification boiled at the same point the first three-fourths of the product being collected. The quantity of pure substance thus obtained exceeds half the original volume of the impure oil.The purified compound presents itself in the form of a clear pellucid fluid of agreeable odour and first insipid though afterwards of a burning taste; miscible with alcohol and ether in all proportions it is perfectly insoluble in water which readily precipitates it from its alcoholic and etherial solutions. It boils exactly at 108O (226~4~ F.) distilling without change to the last drop. It is inflammable and burns with a strongly luminous smoky flame. It dissolves chloride of calcium but to a less extent than the impure oil. Its specific gravity at 18O (644 F.) is 0*894,that of the vapour being 4.053. By combustion with oxide of copper* the following results were obtained * It is impossible to brirn this substance so rich in carbon with either protoxide of copper or chromate of lead alone a small quantity of metallic carbide being formed which occasions a deficiency in the carbon amounting to between 0.5 and 0.8 per cent ; hence combustion with oxygen is absolutely necessary the latter being conveniently evolved from small pieces of perchlorate of potash placed at the posterior end of the combustion tube a plug of dry asbestos preventing contact with the protoxide of VOL 11.-NO.VI. M 162 DR. KOLBE’S RESEARCHES ON I. 0.1825 grm. of substance gave 0.5630 , , carbonic acid and 0.2610 , , water. 11. 0.1578 , , substance gave 0,4855 , , carbonic acid and 0.2260 , , water. These numbers lead to the formula C8 H9 Theory.Experiment. * -8 equiv. of Carbon . 600.0 84.2 84-1 84.0 9 , , Hydrogen . 112.5 15.8 15.9 15.8 712.5 100.0 100.0 99.8 This compound possesses the cornyosition of the hitherto hypo- thetical radical of the still unknown alcohol belonging to butyric acid (C Hg 0 HO) or the radical which in valerianic acid we assume to be in combination with oxalic acid. I propose to call it valyl. Without entering here minutely into the question whether valyl is indeed the radical of an alcohol corresponding to methyl ethyl and aniyl ; I will only mention one fact which in support of such a suppo- sition may seem of some importance; viz. that the specific gravity of its vapour exactly coincides with the number indicated by theory.According to the analogy of the methyl and ethyl series this com- pound would contain 4 vol. of carbon vapour and 9 vol. of hydrogen condensed into 1 vol. hence the density of its vapour would be 3.9387 via. 4 vol. of Carbon . . 3.3168 9 , , Hydrogen . . 0.6219 I 1vol. of Valyl. . 3.9387 Experiment gave the following results Substance employed . . 0*2085grm. Volume of vapour observed . . 63.3~~ Temperature . . . 133.3OC. Barometer . . 7529mm Mercury-column . . 64-0mm Pressing oil-column at 17OC . . 262-0mm copper. In addition to this precaution it is necessary to attach to the common bulbs a tube containing solid potash in order to absorb the aqueous vapour volatilized in the gases passing through the potash apparatus.THE ELECTROLYSIS OF ORGANIC COMPOUXllS. The specific gravity of valyl vapour as calculated from the foregoing numbers is 4.053 closely coinciding with the theoretical value. Valyl is difficultly acted on by oxidizing agents ; moderately strong nitric acid or a mixture of chromate of potash and sulphuric acid have very little action upon it even after continuous ebullition ; strong fuming nitric acid however especially after the addition of sulphuric acid completely oxidizes this compound nitrous fumes being evolved while the oil gradually disappears. On neutralizing with carbonate of baryta evaporating the filtrate to dryness and extracting the residue with strong boiling alcohol the nitrate of baryta remains undissolved. The alcoholic liquid when evaporated leaves a saline residue the distillation of which with sulphuric acid yields a yellow acidulous liquid possessing in an eminent degree the characteristic odour of butyric acid.On neutralizing the solution with freshly precipitated carbonate of silver and filtering whilst boiling a crystalline silver salt is deposited on cooling which is readily darkened by exposure to light or by continued ebullition with the mother liquor. The dry salt does not detolrate when heated The potassium barium and lead salts do not appear to crystallize; want of material has pre- vented me from determining the composition of this acid and of its salts by analysis ; considering however the mode of its formation the peculiar and unmistakeable odour of butyric acid and its yellow colour it becomes very probable that this compound is a mixture of butyric acid and of nitrobutyric acid.Ho> {,"a,> '2'3 '6 corresponding to nitro-metacetonic acid. The following equation represents the transformation of valyl into butyric acid. C H 3-5 O = HOP (c6H,) C 0 + HO. + I-v-2 Valyl. Butyric acid. Dry chlorine has no action on valyl in the dark the minutest ray of light however suffices for the immediate production of hydro-chloric acid vaponrs while chlorinated substitution compounds are simultaneously formed. By an excess of chlorine the liquid gradually becomes converted into a semi-fluid almost viscid mass direct com-bination of chlorine and valyl without elimination of hydrogen does not occur under these circumstances.The action of bromine on valyl although less powerful is attended with similar phenomena ; iodine is dissolved in considerable quantity 3% 2 164 DR. KOLBE’S RESEARCHES ON by it without however entering into combination ; sulphur likewise has no action upon it. The decomposition of valerianic acid into valyl and carbonic acid with the simultaneous evolution of hydrogen is represented by the following equation HO (C H,) C 0 = C H + 2 CO + H. c-v-J + Valeriariic acid. Valyl. which is so extremely simple that further elucidation would be superfluous were not other -products formed at the same time. In order clearly to understand this peculiar reaction we must direct our attention to the study of the two bodies occurring with it; viz.the oxygenated constituent of the impure oil and the odorous gas evolved with the carbonic acid. If we consider the fact of the elimination of valyl at the oxygen pole of the battery the idea naturally suggests itself that a partial oxidatio; of it into oxide of valyl may there be effected; the supposition however that the original oil consists of a mixture of valyl and its oxide is immediately discountenanced by its peculiar deportment with an alcoholic solution of potash unable as we are to understand what kind of compound would be thus produced. The potash solution with which the oil had been boiled when diluted with water to separate the valyl evaporated to dryness and distilled with sulphuric acid was found to contain a considerable quantity of valerianic acid.The presence of this acid may be most easily explained by assuming the existence and decomposition in the liquid of a valerianic ether an assumption which would lead us to consider the oxygenated constituent of the original oil as valerianate of oxide of valyl. The formation of this ether will be easily understood if we bear in mind that together with valyl and oxygen valerianic acid is likewise liberated at the positive pole simultaneously with oxide of valyl in the nascent state. It is true that in the above decomposition by an alcoholic solution of potash according to the analogy of the compound ethers generally hydrated oxide of valyl should have been liberated. If however and it can hardly be doubted the hydrated oxides of amyl valyl and ethyl present the same relation with reference to their miscibility with water as do valerianic butyric and acetic acids the ratios of whose solubility are inversely as their atomic weights it is at once intelligible why with so small a quantity of substance at my disposai I did not succeed in separating the hydrated oxide of valyl from a liquid containing alcohol in solution.THE ELECTROLYSIS OF ORGANIC COMPOUNDS The presence of this compound however was proved to a certain extent by the following observations. The alcohol containing vale- rianate of potash was diluted with water to separate the valyl and distilled off from the valerianate. On introducing the first portion of the distillate into a boiling mixture of bichromate of potash and dilute sulphuric acid a product passed over possessing in an eminent degree the characteristic odour of both butyric and acetic acids.A further confirmation of this view of the composition of the crude oil is afforded by analysis. The substance for investigation was repeatedly washed with water (first with a dilute alkaline solution) dried over chloride of calcium and distilled in vacuo at a low temperature. 0-1175 grm. of the distillate gave 0.3320 , , carbonic acid and 0.1475 , , water. corresponding to the following composition per cent. Carbon . . 77-0 Hydrogen . . 13.8 Oxygen . . 9.2 7 100-0 If starting with the formula c8 H 0 (c8H,) C O3 for the oxygenated oil we calculate from the quantity of oxygen found the per-centage of carbon and hydrogen belonging to this compound we arrive at the following composition 18 equivs.Carbon . . 31.0 18 , Hydrogen . 5.1 4 , Oxygen . . -9.2 45.3 by subtracting these numbers from the above we obtain carbon and hydrogen exactly in the proportion required by the composition of VdYl (C H,) Experiment. Theory. Carbon . . . 46.0 46.1 Hydrogen . . 8.7 8-6 A similar mixture prepared at a different period when subjected to combustion gave the following numbers 0.2647grm. of substance gave 0.7600 , , carbonic acid and 0.3420 , , water. DR. KOLBE'S RESEARCHES ON and a similar calculation leads us to the following results Experimental Composition of Composition of Theory.per-centage. valerianate of valyl. valyl. Carbon . . !:::} 53-3 53.4 { '!I:} Hydrogen minus = 10.1 10.0 Oxygen . . 7.4 100.0 36.6 63.4 63-4 It now only remains to determine the nature of the gas evolved with carbonic acid in the decomposition of valerianate of potash. In order to separate this gas from the vapour of valyl evaporated with it as well as from carbonic acid I passed it from the de- composing apparatus through a system of tubes ($g. 1). dd is an empty tube blown out to a bulb in the lower part and surrounded by a frigorific mixture. In this tube the larger quantity of valyl vapour is condensed a small portion which may have escaped lique- faction being arrested in a Liebig's apparatus g filled with alcohol the vapours of which are condensed in a similar apparatus h containing water.The two following bulbs k and 2 are filled with a solution of potash while the tube rn contains potash in the solid form serving both for the separation of carbonic acid and for the complete dessi- cation of the gas. Finally to obtain a perfect mixture the evolved gases were collected in the gas-holder B which consists of a cylinder of glass 3 inches in diameter and 11 inches in height containing an inverted bell-jar open at the lower extremity and enclosing one vertical branch of each of the two U-shaped tubes s and x. The bell- glass is fixed by a holder in its lowest position and the apparatus filled with mercury to such an extent that the two tubes through which the air contained in the bell-jar is expelled rise only a few lines above its surface.The tube s moreover at its horizontal extremity is connected by an air-tight caoutchouc joint with the tube m while the branch x communicates in the same manner with the delivery tube r which may be opened or closed at pleasure by depressing or elevating it from the mercury of the trough; both the connectors being moreover furnished with caoutchouc valves. When the evolution of gases occasioned by closing the galvanic circuit in the decomposing apparatus had lasted nearly half an hour without interruption and all the air contained in its different parts had evidently been expelled the caoutchouc valve v was closely tied while the holder with which the bell-jar had been depressed in the mercury was gradually elevated as the vessel became filled with the gas generated by the decomposition.When a sufficient quantity of gas THE ELECTROLYSIS OF ORGANIC COMPOUNDS. had been collected in this manner the evolution was interrupted by breaking contact. By now tying the valvep the gases contained in the gas-holder were no longer in connexion with the generating apparatus By opening the valve v and depressing the bell-jar the quantity of gas required could easily be collected over mercury and then transferred into the eudiometer or into the glass balloon for the determination of its specific gravity. In determining the specific gravity the following numbers were obtained Vol.of gas in balloon . . . 15O C. 755*9"ln1 86.4 c. c. Weight of balloon filled with gas 15O , 7'71.0 , 6106.28 grm. , J , air 15O , 771.0 , 61.672 , From the above numbers the specific gravity is calculated as 0.604. In performing the eudiometrical analysis I availed myself of the circumstance of the odorous constituent being absorbed by sulphuric acid. I therefore introduced into a measured volume of the gas a coke ball saturated with strong fuming acid; the sulphurous acid together with the sulphuric vapours being subsequently removed by a moistened ball of potash. In this manner the following numbers were obtained I. ob:$ed. Temp. Bar. Height of mer-cury above level in the trough. Corrected vol. 00 C. lm. Press. Original vol. (dry) 117.7 with sulphuric acid 88.8After absorption 1and potash (dry) 9.9 9.0 765.9""' 761.1 , 65*Omm 93.3 , 79.6 57.4 The quantity of odorous substance in the mixed gases absorbable by sulphuric acid consequently amounts to 27.8 per cent.The residual gas no longer possessing any odour and burning with a pale blue non-luminous flame was transferred into a eudiometer furnished with platinum wires and exploded with oxygen when it was found to consist of pure hydrogen. Another portion of the above mixture when exploded with oxygen gave the following results 11. VOl. Height of mer-Corrected observed. Temp. Bar. cury above level vol. in the trough. 00 C. lm. Press. DR. KOLBE~SRESEARCHES ON After admission of 11.1 759.3"'" 141.9"" 189.5 oxygen (moist).}324.6 After combustion (moist). }222*7 11.1 759.0 9 242.3 jJ 108.4 After absorption Of 146.0 13.0 759.1 j 318.2 , 61.4 co (dry). The gas remaining after the absorption of carbonic acid consisted only of pure oxygen as had been ascertained in a previous experiment. The above analysis leads to the following results Volume of combustible gas. Oxygen consd. Carbonic acid prodd. 42.4 . . 85.7 . . 47.0 or 100-0 . . 202.1 . . 110*8 The mixture of gases under investigation containing according to experiment 11 72.2 per cent. of hydrogen requires 36-1 vol. of oxygen for its combustion; it is therefore evident that the remaining 27.8 vol. require 166 (= 202.1 -36.1) vol. of oxygen in order to produce 110.8 vol. of carbonic acid.These numbers stand very nearly as 1 6 4 or in other words 1 volume of the odorous gas requires 6 vol. of oxygen to produce 4 vol. of carbonic acid. Four vol. of carbonic acid consisting however of 2 vol. of carbon and 4 vol. of oxygen and altogether 6 vol. of oxygen having disappeared 2 vol. having evidently served for the combustion of 4 vol. of hydrogen it is obvious that the odorous gas contains 2 vol. of carbon and 4vol. of hydrogen condensed into one volume ; hence its specific gravity is 1.934. 2 vol. of Carbon vapour . 1-658 4 , , Hydrogen . . 0.276 -1 ,I H,c ,> . 1.934 According to the above experiment the specific gravity of a mixture of 72.2 vol. of hydrogen and 27.8 vol. of the carbo-hydro- gen is equal to 0.604; hence it follows that the specific gravity of the latter alone is 1.493 closely coinciding with the result of experiment.The odorous carbo-hydrogen evolved at the positive pole in the electrolytical decomposition of valerianate of potash according to these experiments exhibits the composition of olefiant gas but possesses a specific gravity double that of this compound. In this respect it agrees with the carbo-hydrogen discovered by Faraday THE ELECTROLYSIS OF ORQANIC COMPOUNDS. and named by Berzelius ditetryl with which it in fact appears identical by its comportment with chlorine. If the mixed gases washed with potash and alcohol and collected in the gas-holder be passed through a chloride of calcium tube into a flask (provided with three tubulures one of which terminates in a narrow aperture) and mixed with perfectly dry chlorine an excess being carefully excluded and light as much as possible avoided the sides of the flask become quickly covered with oily drops which soon collect into larger globules and flow out from the lower aperture while hydrochloric acid formed by the direct combination of chlorine with the free hydrogen is disengaged.During the whole process a slight evolution of heat is perceptible. About half an ounce of the oily liquid which had been collected in the vessel placed under the lower aperture of the flask was first treated with slightly alkaline and afterwards with pure water in order to separate dissolved hydrochloric acid; it was then dried over fused chloride of calcium and subjected to a fractional distil- lation.The portion which boiled between 125"C. (257' F.) and 130' C. (266" F.) forming by far the larger quantity was separately collected and purified by repeated rectifications when a nearly con-stant boiling-point at 123' C. (253.4F.) was obtained. This compound possesses the following properties. It is a clear colourless etherial liquid insoluble in and heavier than water. It has an agreeable sweetish odour and taste deceptively similar to that of Dutch liquid. It dissolves with facility in alcohol and ether and boils at the constant temperature of 123"C. (266O F.) ; mixed with alcohol it burns with a luminous smoky flame with evolution of hydrochloric acid. Its specific gravity at 18O C.(64.4F.) is 1.112 the density of its vapour 4*426#the latter being calculated from the following data Substance employed . . 0,244grm. Vol. of vapour observed . . 67.7 c. c. Temperature . . 139*OoC. Bar. pressure . . 751.0 ram. Col. of mercury to be deducted . 51.0 , Pressure of oil col. at 17O C. . 366.0 , By combustion with protoxide of copper the following results were obtained I. 0.3990 grm.of substance gave 0.5590 , , carbonic acid and 0.2470 , , water. DR. KOLBE’S RESEARCHES ON 11. 0.2165 , , passed over ignited lime dissolved in nitric acid and precipitated with nitrate of silver gave 04790 , , chloride of silver. These numbers coincide with the formula C H CI or C H (21%. Theory.Experiment -8 equiv. of Carbon . . 600.0 37.8 38.2 8 , , Hydrogen . 100.0 6.3 6.8 2 , , Chlorine . 886.0 55.9 55.5 1586-0 100.0 100.5 If we adopt in this compound a similar condensation of the elements as in the oil of olefiant gas the specific gravity of its vapour should be 4.3837. 2 vol. of Carbon . . 1.6584 4 , Hydrogen J . 0.2764 1 , Chlorine . 2.4489 1 # , the new Chloride . 4.3837 (with this number the result of experiment 4426 closely coincides). It would have been extremely interesting to have studied the aomportment of this compound with an alcoholic solution of potash since its analogy to chloride of elayl justifies the expectation that in this case chloride of potassium and a compound corresponding to chloride of acetyl would have been formed the latter being repre- sented by the formula The small quantity of liquid at my disposal unfortunately did not allow me to pursue the subject any further.I must therefore confine myself to mentioning that on heating an alcoholic solution of the compound with potash a copious crystalline precipitate of chlo-ride of potassium was formed while the characteristic odour of the compound was replaced by that of a very volatile liquid having probably the formula which remaining dissolved in the alcoholic solution was precipitated THE ELECTROLYSIS OF ORGANIC COMPOUNDS. 171 on the addition of water in small drops which separating at the sides of the vessel united only with difficulty; the liquid remaining milky for a considerable period.By the action of chlorine on the above carbo-hydrogen with the fluid boiling at 123O C. (253O.4 F.),higher chlorinated products are formed even when an excess of chlorine has been carefully avoided. The slow elevation of the boiling-point from l23O C. (253O.4 F.) to 1600 C. (320O F.) at once intimates that we have in this case other substances richer in chlorine which possibly might have been sepa- rated by fractional distillation of a larger quantity. The combustion of 0.3620 grm. of the product distilling at 132O C. (269O.6 F.) gave 0.4600 grm. of carbonic acid and 0*1800grm. water corresponding to the following per-centage composition Carbon . . 34.6 Hydrogen 5.5 A compound still richer in chlorine is obtained by passing the gas through pentachloride of antimony and distilling the substance thus produced.During the process of absorption the mixture blackened with the evolution of hydrochloric acid. The oily product obtained was purified by repeated distillation with water dried over chloride of calcium and subjected to analysis when it exhibited the following per-centage composition Carbon . 28.4 Hydrogen . 4.0 Chlorine . . 68.2 being evidently a mixture of different chlorinated compounds whose composition may be represented by the general formula The opinions of chemists regarding the rational composition of the oil of olefiant gas are as is well known still divided as to whether it should be considered as the chlorine compound of a radical C H, or whether its atomic weight should be doubled in which case it would appear as the hydrochlorate of chloride of acetyl.This question must remain undecided as long as both views can still claim arguments of equal force. Now whichever of these opinions may in future be found correct it will evidently determine our views 172 DR. KOLBE'S RESEARCHES ON respecting the chemical constitution of the above chlorinated oil pro- duced from ditetryl or in other words it will decide whether we have to adopt the formula C4K4CI or c,{ ,H;I} HCI as the true exponent of its rational composition. This supposition once recognised will add new force in favour of the latter mode of representation if we bring to bear upon this case the law of Kopp respecting the regularity displayed in the boiling points of homologous liquids (to employ an expression lately introduced to designate the members of such series of bodies) which like the alcohols or the fatty acids are represented as being derived from a starting member by the addition of n times C H, C H, on any other carbo-hydrogen ex- periment having (within certain limits) evinced the fact that the boil- ing points of homologous fluids rise 19O C.(34OF.) for each additional equivalent of the carbo-hydrogen C H,. The chloride of ditetryl C H Cl which boils at 85' C. (185' F.) differing from chloride of elayl by one equivalent of the carbo-hydrogen C H should boil at 104O C. (219O-2F.) ;on doubling however the atomic weight of the two bodies (chloride of elayl C H Cl, and chloride of ditetryl C H8 ClJ their elementary difference becoming equal to 2 (C H,) the boiling point of the latter should be 123O C.(253O.4 F.) which is the temperature actually observed by experiment. Although this observation cannot be considered as a direct argument for the assumed molecular arrangement I consider it nevertheless of sufficient weight to assist in the ultimate decision of the question regarding the atomic constitution of the two compounds. We find no difKculty in explaining the formation of the carbo- hydrogen C H, or c8 H from vderianic acid; like the valerianate of the oxide of valyl it is evidently a secondary product of the decom- position of valyl and most probably formed by the action of the oxygen separating along with valyl at the positive pole.We may assume that under the influence of this oxygen valyl is deprived of one equivalent of hydrogen yielding one equivalent of ditetryl and one equivalent of water. The action of electrolized oxygen on a solution of valerianate of potash therefore gives rise to three distinct phenomena 1st. A decomposition of the acid into valyl and carbonic acid HO (C H,) C O,+O=C H,+2 CO,+HO. -v3 + Valeride acid. Valpl. THE ELECTROLYSIS OF ORGANIC COMPOUNDS. 2ndly. The decomposition of valyl into ditetryl and water C H + O=Z (C H4) + HO. LlrJ v Valyl. Ditetryl. 3dly. A direct oxidation of valyl into oxide of valyl which com- bines in the nascent state with free valerianic acid.c Hg+ 0+ (C H,) c 0,=c Hg 0,(C Hg)c 0,. + \+ L-v-J Valyl. Valerianic acid. Valerianate of oxide of valyl. The two latter processes appear to take place simultaneously though perfectly independent of each other. I have not however succeeded in exactly ascertaining the circumstances which favour the formation of the one or the other. ELECTROLYSIS OF ACETIC ACID. The remarkable analogy of the series of acids (C H& + 04,induced me to believe that acetic acid would undergo a similar decomposition to valerianic acid yielding by absorption of one equivalent of oxygen methyl and carbonic acid HO (C2HJ Cz03-I-O=C2H3+2C02+H0. Acetic acid. Methyl. In a preliminary experiment it was found that on decomposing a concentrated solution of acetate of potash gaseous products only were evolved consisting of carbonic acid hydrogen a combustible inodorous gas and a compound possessing a peculiar etherial odour and absorbable by sulphuric acid.In the investigation of these gaseous products I availed myself of the same decomposing apparatus as was employed in the decomposition of valerianic acid ; the evolved gases were first passed through a series of bulb tubes containing potash afterwards through a tube filled with sulphuric acid (for the absorption of the odorous gas) and finally made to pass through a tube containing pieces of fused hydrate of potash previous to collection in a gas-holder. In this operation it is necessary to employ a very concentrated solution of the potash salt perfectly free from chloride of potassium the smallest trace of the latter giving rise to the formation of chloride of methyl which is easily recognisable by the green-bordered flame with which it burns when inflamed in contact with the air.* * In a similar manner various other secondary product8 are formed a mixture of DR.KOLBE’S RESEARCHES ON When the evolution of gas had continued for about an hour and had entirely displaced all traces of atmospheric air contained in the system of tubes and the gasometer I filled the latter by gradually raising the bell the delivery tube dipping under the mercury. The apparatus being too small to allow a sufficient quantity of gas being collected for taking its specific gravity for eudiometrical analysis and for combustion with protoxide of copper the bell-jar was again fixed before being completely filled and the gas issuing from the tube r was collected in a flask for the determination of the specific gravity.The contents of the gasometer were now easily confined by tying the caoutchouc valvesp and v over the inserted glass rods after the collection of gas had ceased from the interruption of the galvanic current. In determining the relative proportion of carbon and hydrogen an ordinary combustion-tube open at both ends was employed ; when filled with freshly ignited protoxide of copper the anterior extremity was connected with the usual potash bulbs and chloride of calcium tube the posterior end being attached by a caoutchouc tube to the gasometer.After opening the caoutchouc valve v the silken cord was untied and by gently depressing the bell-jar a continuous stream of gas passed over the ignited protoxide of copper until a sufficiency of carbonic acid and water had been collected when the caoutchouc valve was again closed. The posterior tube connected with the gas-holder was now cut in order to allow of theremoval of the carbonic acid remaining in the apparatus. The following are the numbers obtained Carbonic acid . 0.2470 Water . . . . 0,2635 corresponding to a ratio of 1 equivalent of carbon to 2-06equivs. of hydrogen or of 1 volume of carbon vapour to 5.2vols. of hydrogen. The specific gravity of the gas collected in a small flask over mercury was found to be 0.403.Temp. Pressure. Volume of gases in flask . . . 19.3OC.749.2“” 211.3c c. Mercury column to be deducted . . . 15.0 , .. Weight of flask filled with gas 22*OoC. 749.0, 46.669 grm. Weight of flask Elled with air . -46.819 , vderianate of potash and chloride of potassium for example produces in the place of vdyl a chlorinated etherial compound ; a disagreeably smelling compound is obtained by exposing a mixture of acetate of potash and sulphide of potassium to the action of a galvanic current the anode being formed of a platinum plate. THE ELECTROLYSIS OF ORGANIC COMPOUNDS. The further data for the composition of the gas were obtained by eudiometrical analysis which exhibited the presence of a minute quantity of oxygen. Corrected Observed.Temp. Bar. voI. 0%. and tr&hi$::f-lm pressure. Volume of gas employed 1137.3 19~3OC. 747.2"" 3105~~89.6 (moist). After absorption of oxygen 1132.0 19*O0, 7400 , 35.9 , 86.9 (moist). The quantity of oxygen therefore amounts to 3 per cent. The residuary gas was transferred into a larger eudiometer and detonated with oxygen in experiments I1 a. and I1 b. the following numbers were obtained I1 a. Height of Corrected vol. Observed vol. Temp. Barom. mercury 00 C. and lm C" column. pressure. Volume of gas ern ployed (moist). } 200.0 18.0 749.0"m 373.4"" 67.6 After admission of } 475.9 17.4 751*2, 92.3 , 287.6 oxygen (moist). After 345.6 18.0 751.1 , 225.6 , 165.4 (moist). 1 After absorptionof 283.2 17.7 7a.8 , 288.6, 122.3 carbonic acid (dry) 1 .", After admission of 574.5 17.8 747m5, 6% 399.0 hydrogen (dry). 1 after (moist). } 114.2 17.4 748.9, 460.2 , 29.4 I1 b. Volume of gas em-} ployed (moist). 91.8 18.9 740.2 , 476.3 21.26 After admission of 410.2 19,0 740.3 , 153.7 , 218.7 oxygen (moist). 1 After combus tion 3662 19.0 7404, 197.1, 180.43 (moist). After absorption of carbonic acid 341.4 18.0 7440, 167.15 i (dry) > 222.1 176 DR. KOLBE'S RESEARCHES ox Vol. of gases Oxygen Carbonic acid used. consumed. generated. Experiment I1 a. .....67.6 97.7 43.1 Experiment I1 6. .....21.26 30.3 13.3 In calculating these numbers for a mixture of hydrogen and methyl we find that in both experiments a smaller quantity of oxygen has disappeared than is required for the perfect combustion of such a mixture.This circumstance. appears to point out the presence of oxide of methyl which accompanies methyl itself in pretty constant propor-tion. In designating the quantity of combustible gas employed by A the oxygen which has disappeared by 23 the carbonic acid produced in combustion by C; and further the quantity of oxygen methyl and of oxide of methyl respectively by x y and z we arrive at the following equation xi-y+ z=A 3~+34y+3z=B 2y+2z=c by which we obtain for x y and z the following values 28-C X= 2 4B-2A-5C Y= 2 z=A +3 C -2B. If we now substitute for A B and C the numerical values found we arrive at the following coniposition for the two consumed volumes of gas (Exp.I1 a and I1 b) Experiment I1 a. Experiment I1 8. Hydrogen .....46.1 14.60 Methyl ......20.0 6.10 Oxide of methyl ... 1.5 0.56 ~~ -Total volume ..67.6 21-26 Hence from experiments I. and II. results the following per-centage composition of the mixed gases Oxygen ......... 3.0 3.0 Hydrogen ........66.0 66% Methyl .........28.8 27.8 Oxide of methyl ...... 2.2 2-6 100.0 100.0 THE ELECTROLYSIS OF ORGANIC COAIPOUNDS. The specific gravity of a gaseous mixture of this composition would be 0.4123 which closely coincides with the numbers found by experiment 0.403. This composition receives further confirmation from the relative proportions of carbon and hydrogen obtained by combustion with protoxide of copper.Carbon vapour. Hydrogen. 28% vol. Methyl contain 28.8 vol. 86.4 vol. 2-2 , Oxide methyl , 2.2 I 6.6 ,, -66.0 , Hydrogen 66.0 ,> > 9 The gaseous mixture . . . . 31.0 , 159.0 , Being the ratio of 31.0 vol. of carbon vapour to 159.0vol. of hydro-gen or of 1 vol. of carbon vapour to 5.13 vol. of hydrogen very closely coinciding with the above experimental ratio of 1 5.21. I have before mentioned that the gases evolved in the electrolysis of acetic acid contain a gas which is absorbable by sulphuric acid. Independently of the remarkable odour of acetate of methyl which this gas possesses the supposition that acetate of methyl is actually obtained among the products of the decomposition of acetic acid receives some support from the analogous decomposition of valerianic acid.With the view of ascertaining the per-centage of this body in the mixture of gases and to study its nature I repeated the above experiments with a portion of gas which had not previously been passed through sulphuric acid and which consequently still contained the odorous principle ; it burned like the other with a feebly lumi- nous bluish flame. An indefinite volume being passed from the gas-holder over ignited protoxide of copper gave 0.249 grm. of carbonic acid and 0.247 , , water. Corresponding to the ratio of 1 vol. of carbon vapour and 4.851 vols. of hydrogen. The specific gravity of the mixture was found to be 0.4373 as is seen by the following experiment Temp.Pressure. C. Volume of gas in flask . . . 18*0° 741-0mm 211.7 cc. Weight of flask filled with gas . 19*Oo 749.0 , 42.4065 grm. >> 9 > 9 , air -42.5500 , VOL. XI.-No. VI. N IIR. KOLBE'S RESEARCHES ON TOascertain the per-centage of free oxygen and of the odorous constituent I first determined in a measured volume (experiment III) the quantity of the latter by absorption with a coke ball saturated with sulphuric acid and subsequently the amount of oxygen by introducing a ball of phosphorus. The remaining portion of com-bustible gas was then detonated with oxygen in a large endiometer (experiment IV). 111. Observed vol. Volume of gas used 1116.4 (moist). C.Temp. 17.8 Bar. 747.2"" Height of column.mercury 21.2"" Corrected vol.lmpressure. Oo C. and 77.67 After. absorption 7 with sulphuric acid 17.9 746.0 , 24.8 , 77.03 (dry).After absorption of 1113.0 oxygen (dry ) . 17.6 746-0, 25.1 , 76.5 IV. Volume of gas free from oxygen and odorous constituent 190.6 17.8 746.0 , 378.2 , 63.1 (moist). After admission of} 373,9 oxygen (moist). After combustion } 208.6 (moist). 17.9 18.0 744.7 , 743%, 192.4 , 339.6 , 188.4 72.17 After absorption of} 105.3 18.2 745.9 , 465.7 , 27.66 carbonic acid (dry). } After admission of 311.5 18.0 750.6 , 255.7 , 144.63 hydrogen (dry). 18.1 750.6 , 386.5 , 62.35 According to the latter experiment it follows that 63.1 vols. of gas previously treated with sulphuric acid and phosphorus require for combustion 97.4 volumes of oxygen giving rise to the formation of 44.51 vols.of carbonic acid. If we now calculate these numbers according to the above equation for hydrogen methyl and oxide of methyl we find that the original 63.1 vols. contained 40.85 vols. of hydrogen 20.9 vols. of methyl and 1.35 vol. of oxide of methyl. From these data and likewise from the results of experiment 111 we obtain the following per-centage compositiorr of the mixture in THE ELECTROLYSIS OF ORGANIC COMPOUNDS. which the gas absorbable by sulphuric acid is enumerated as acetate of methyl. Oxygen . . 0.7 Hydrogen . Methyl . Oxide of methyl . . . . 63.8 32.6 2.1 Acetate of methyl . . 0.8 - 1000 The specific gravity of such a mixture should be 0.4430,which does not far differ from experimental results the number obtained being 0-42370 Volume Specific Weight.per-cent . gravity. Oxygen . . . 0.7 x 1.1092 = 0.7647 Hydrogen . . . 63.8 x 0.0691 = 4.4086 Methyl . . . . 32.6 x 0.0365 = 33.7899 Oxide of methyl . 2-1 x 1.5893 = 3.3375 Acetate of methyl. 0.8 x 2.5567 = 2.0454 If we calculate the relative volumes of carbon and hydrogen con-tained in this mixture of gases we obtain the following numbers vapour. Hydrogen. 63.8 vol. H containing -63.8vol. 32.6 , C H I 32.6 vol. 97.8 2.1 , C H 0 , 2.1 , 6.3 , I, 0.8 ,Y c H 0 1.2 , 2.4 , Being a proportion of . 35.9 to 170.3 , or of one volume of carbon vapour to 4.74 vols. of hydrogen which coincides with the results obtained by combustion with protoxide of copper viz 1 vol.of carbon vapour to 4.85 vol. of hydrogen. The per-centage composition gains additional support by the eudiome- trieal analysis of the same gas which still contained the odorous principle but which was previously freed from oxygen. The following numbers were obtained N2 ,> DR. KOLBE'S RESEARCHES ON V. Height of Corrected vol . Observed vol. Temp. Barom. mercury Oo C. and lm C. column. pressure. Volume of gas 138.0 18.2 750.5mm 432-6mm 39.11 used (moist). } After admission of 360.6 18.3 750.2 , 206.4 , 178.5 oxygen (moist l-After combustion 263.9 18.2 750.1 , 303*9, 106.8 (moist). After absorption of carbonic acid 213.9 18.2 748.4 , 354.0 , 78.9 (dry)* i In the combustion of 39.1 vols.of this gas 60.5 vols. of oxygen are consumed giving rise to the formation of 27.9 vols. of carbonic acid. By now calculating the quantity of oxygen necessary for the com-bustion of 63-53vols. of hydrogen 32.6 vols. of methyl 2.1 vols. of oxide of methyl and 0.8 vol. of acetate of methyl and likewise taking into consideration the amount of carbonic acid produced we arrive at results but slightly differing from the numbers obtained by experiment Oxygen. Carbonic acid. 63-8 vols. of H requiring for combustion 31.9 vols. and producing -99 91 ?? 32.6 ?) C,H3 114.1 , , 65 2 vols. I? Y? 97 2.1 9 C,H3O -,? 6.3 9 ? 4'2 17 0.8 7 9) C,H,O,A 99 9 -2.8 1) 2-4 I7 99.3 vol. of mixed gases -155.1 vols. 71.8 , or that 39.1 vols. require for combustion 61.0 vols.of oxygen (expe- rimental result 60.5 vols.) producing 28.2 vols. of carbonic acid (experimental result 27.9). These facts sufficiently prove that the quantity of the compound imparting the peculiar etherial odour to the gases which are evolved in the electrolytical decomposition of acetate of potash is so small that if as experiment seems to point out it actually consists of acetate of methyl it becomes almost impossible to condense it by a low temperature. An experiment made with this view was indeed perfectly unsuccessful. The ready abscrption of this body by sulphuric acid agrees with the comportment of acetate of methyl; the acid employed in the experiment assumed a yellowish tint and darkened on the application of heat with the evolution of acetic and sulphurous acid vapours.The above experiments had been completed when I became aware THE ELECTROLYSIS OF ORGANIC COMPOUNDS. that a gaseous mixture consisting of one-third methyl and two-thirds of hydrogen possesses the same specific gravity as is exhibited by a mixture of two-thirds of marsh-gas and one-third of hydrogen and moreover both mixtures contain the same relative amounts of carbon and hydrogen and consequently consume not only an equal volume of oxygen in their combustion but produce the same quantity of carbonic acid; and hence the facts observed in the electrolysis of acetic acid might lead to the assumption that the gases evolved in its electrolytical decomposition consist of hydrogen and marsh- gas.With the view of removing all doubt on this point I have endeavoured to prepare methyl in a state of purity I availed myself for this purpose of the decomposing apparatus (jg.2 b) already described which allows us to collect with facility the products liberated at either pole. The interior cell containing the platinum plate was closed for this purpose with the cork which besides the platinum wire for producing contact contained moreover the delivery tube through which the generated gases were evolved in order to be conducted through two bulb-tubes filled with concentrated solution of potash and afterwards through a similar vessel containing sulphuric acid (for the absorption of water and acetate of oxide of methyl) and subsequently collected in the gas-holder.After every trace of atmospheric air had been expelled the collected gas contained nevertheless a small quantity of carbonic acid the two potash bulbs not having been sufficient to absorb the carbonic acid which had been evolved from the separated cell in much larger proportion than in the former arrangement because in the former experiment the simultaneous liberation of acetic acid at the positive pole effectually prevented the formation of a carbonate. The eudiometrical analysis of the mixture which as special expe- riment had proved did not contain free oxygen gave the following results VI. Observed vol. Temp. C. Barom. Height of mercury column. Corrected vol. Oo C. and lm pressure. Of gas}used (moist).of carbonic acid After absorption 121.9 17.3 90.9 17.2 738*6mm 744+3, 18*2mm 44.9, 80.9 59-86 (dr39. DR. KOLBE’S RESEARCHES ON VII. Gas used 114.1 175 744*grnm 457-4mm 29-23 (moist). 1 After admission of 452.0 175 745*2, 115*7, 261.1 oxygen (moist). 1 After combustion 374.0 17-6 745*2, 192*5, 188.9 (moist). } After absorption of carbonic acid 293.5 17.5 746*0, 273*6, 130.5 (dry). According to these observations the gaseous mixture contains 26.0 of carbonic acid and 74.0 of combustible gas of which (experi- ment VII) 29.23 vols. require 101.37 vols. of oxygen for complete combustion producing 58*4 vols. of carbonic acid which closely corresponds with the ratio 1 34 2; hence it appears that the gas evolved with carbonic acid at the positive pole is actually methyl containing not even a trace of marsh-gas which requires the double volume of oxygen for its complete combustion and produces only an equal volume of carbonic acid.The experimental numbers correspond with the following per- centage Carbonic acid. . 26.0 Methyl . . 69-3 Oxide of methyl . . -4.7 100.0 The specific gravity of such a mixture is 1,188 a number closely coinciding with the result of experiment which gave 1.172 as the following data will shew Temp. Barometer. Volume of gas in flask . . . 17.3O 717.8 212 c. c. Weight of flask filled with gas 17-fL0 738.6 53.826 grm. J ,J >Y air -53.796 , The gas remaining after the absorption of carbonic acid (experiment VI) which is methyl mixed with traces of oxide of methyl possesses the following properties it is inodorous* and tasteless insoluble in water and burns with a bluish non-luminous flanie ;alcohol dissolves an equal volume absorbing it without residue; neither sulphuric acid * The feebly etherid odour of the gas prepared from cyanide of ethyl evidently arises from traces of cyanide of ethyl.> THE ELECTROLYSIS OF ORGANIC COMPOUNDS. nor pentachloride of antimony dissolve it and hence it corresponds in all its properties to the gas obtained from cyanide of ethyl.* Methyl may be distinguished from marsh-gas to which it is in some respects very similar both by its solubility in alcohol and its comportment with an excess of chlorine gas by which methyl is con-verted into sesquichloride of carbon while marsh-gas is transformed into the bichloride.In conclusion I may observe that on employing two decomposing cells the gas evolved at the positive pole does not contain carbonic acid but consists of pure hydrogen. According to the observations I have communicated acetic acid when decomposed in the circuit of the voltaic current is decom- posed into methyl and carbonic acid both being liberated at the positive pole whilst at the negative pole pure hydrogen only is evolved. It further appears that a sniall quantity of methyl is converted into the oxide. On leaving out of consideration the small quantity of the latter one equivalent of acetic acid should accord- ingly yield 2 vols. of hydrogen 2vols.of methyl and 4vols. of carbonic acid as is shown in the following equation fH 2vols. HO (C H3) C O,= C H 2voh 12c 0 4 vols. The gases evolved from the decomposing cell in the decomposition of acetate of potash should therefore consist of equal volumes of methyl and hydrogen; as however experiments 11 IV andV show that nearly double the amount of hydrogen is evolved without an equivalent proportion of oxygen being liberated we are led to the conclusion that together with the above-mentioned transformations a simultaneous decomposition of water takes place whose oxygen (considerably surpassing the amount contained in the oxide of methyl) evidently oxidizes a portion of the liberated methyl com-pletely into carbonic acid and water; from this fact however it would follow that carbonic acid would be produced in much larger proportion compared with methyl than is indicated by the foregoing formula.With the view of deciding this question I have investigated the mixture of carbonic acid and methyl evolved at the positive pole which had been previously freed from acetic vapours which might have been carried over by passing the gas through a bulb-tube containing water. * Ann. det Chem. und Phdim. Bd. LXV. S. 269. 184 PRESIDENT’S ADDRESS. VIII. Corrected voI. Observed vol. T’olnme Of gas} 110.2 (moist). After absorption 35.3 Temp. C. 17.0 15.8 Barom. 764,Omm 753.3, Mercurycolumn. 25.3”“ 99.0 , 00 C. and lm pressure. 73.27 21.96 The gaseous mixture under investigation was found to contain 21-96 vols.of methyl and 51.31 vols. of carbonic acid; or in other words for every volume of the former there are 2$ volumes of the latter instead of 2 volunies as indicated by the above equation. These observations appear sufficient to prove that in the electro- lysis of acetic acid even when employed in the form of a concentrated solution of its potash salt a simultaneous decomposition of water takes place which may perhaps be partially or entirely avoided by modifying the electrical current.

ISSN:1743-6893    

DOI:10.1039/QJ8500200157

出版商:RSC    

年代:1850

数据来源: RSC

摘要:

PRESIDENT’S ADDRESS. Anniversary Meeting March 30 1849. The President in the Chair. The following Report of the Council was read by the President. Annual Report of the Council. We have now Gentlemen arrived at our Eighth Anniversary and ifbecomes my duty as the Delegate of your Council to advert to the general concerns of the Society during the preceding year. Our Society is at present constituted of one hundred and twelve resident and one hundred and twelve non-resident Members ; three Associates; and nine Foreign Members. In the course of the past year twenty-nine new Members have been elected namely fourteen resident and fifteen non-resident. The list of Members deceased during the past year is less extensive than usual being limited as I believe to two individuals; but in one of them I regret to say this Society has sustained an especial loss; 1 allude to the death of one of our original Members and our late Secretary Ah.Fownes which took place at his father’s house at Brompton on the 31st of last January before he had completed his 34th pear having been born on the 14th of May 1815. Mr. Fownes received his early education first at Enfield and afterwards at Bourbourg near Gravelines in France. He was PRESIDENT’S ADDRESS. originally intended for trade but having an inherent attachment to the pursuits of Science those of business proved so irksome and distasteful to him that he was soon induced to relinquish them and to adopt Chemistry as his profession. This resolve was materially influenced by his becoming when about seventeen or eighteen years of age a member of the Western Literary Institution where in conjunction with $!h.Everitt Mr.Henry Watts Mr. R. Murray and others he established a philo- sophical class in which he displayed much readiness as a demon-strator and great zeal in promoting experimental inquiry. In January 1837 he became a pupil of our late colleague Mr. Thomas Everitt who then filled the Chair of Chemistry at the Middlesex Hospital ; he afterwards visited Germany and availed himself of the aids of the celebrated school of Giessen from which he returned with the degree of Ph.D. Soon after his return from Germany it was his good fortune to become an assistant in the Laboratory of University College under the tuition of Professor Graham and he soon showed himself not an unworthy pupil of that eminent master.From these several sources Mr. Fownes derived a store of practical and theoretical knowledge which fitted him to become himself an instructor in the science which he loved and to which he was now laboriously devoting himself; and he undertook in the first instance the Chemical Lectureship at Charing Cross Hospital. In February 1842 he wrote an Essay on the Food of Plants which was presented to the Royal Agricultural Society and to which the prize of that Society was adjudged in December following.-It is an elaborate and valuable paper and has a place in the Journal of the Society for 1844. In 1842 and 1843 he delivered two short courses of lectures at the Royal Institution.In the summer of 1842 he was appointed the Professor of Chemistry to the Pharmaceutical Society the duties of which office he entered upon in October of the same year. About this time also he left the Charing Cross Hospital and upon the death of Mr. Everitt succeeded to the Chemical Lectureship of the Middlesex Hospital; and in addition to these laborious duties he gave occasional lectures elsewhere and more especially at the London Institution where in the year 1844 he gave a course on Chemical Philosophy. But now it unfortunately became apparent that his health was suffering. With unimpaired mental energies his bodily strength began to decline and evident symptoms of pulmonary disease made their appearance under the form of a troublesome cough and shortness of breath which rendered lecturing a severe PRESIDENT’S ADDRESS.labour so that in the year 1845 he resigned his office at the Middlesex Hospital and in the following year was forced to relin- quish the duties of his Pharmaceutical Professorship. He was how-ever in the meantime appointed the Professor of Practical Chemistry in the Birkbeck Laboratory at University College an appointment which he held at the time of his decease. In the summer of 1846 he visited Switzerland and returned in the autumn in improved health and spirits; but winter again rendered him unable to do the work he wished and obliged him to desist from those original researches in Organic Chemistry which he had already pursued with so much success and in which he would doubtless have achieved new and important conquests.The spring of 1847 found him still further worn and exhausted by the ungenial influence of the preceding winter; and though in the course of the summer he appeared somewhat to rally and improve it became evident to his medical advisers that he could not in safety sustain another English winter ;he therefore at the suggestion of his friend Dr. B. Jones determined upon seeking a warmer climate and went to Barbadoes. Early in the following spring he returned to this country; but unfortunately a severe cold caught on the passage deprived him of much of the advantage which it was hoped he had derived. His health now began more evidently and rapidly to give way and he was induced to repair to Torquay but finding his sojourn there of no avail he returned to his home at Brompton where he passed the short residue of his earthly existence.Mr. Fownes was SO well known to the majority of the Members of this Society that I need say little upon the amiability of his dis- position his disinterested love of science at large or his skill his industry and his success in that branch of it which he more exclusively adorned and in which had it pleased Providence to have extended his sojourn amongst us he must at no very remote period have established an imperishable name. As a public lecturer and generally in his didactic capacity his language mas clear and concise his manner earnest and agreeable his matter admirably arranged and carefully selected.He had indeed considering the short time in which he had been engaged in the difficult business of teaching Chemistry acquired a singular command over the lecture table much dexterity in the public performance of illustrative expe- riments and in that methodical aptitude which ensures the attention of the hearer by at once amusing and instructing him and which makes obscure truths plain and dry details attractive. As an original inquirer hc had as I have before observed already PRESIDEINT’S ADDRESS. 187 laid the foundation upon which a permanent and worthy superstruc- ture would doubtless have been raised to this his various contribu- tions to Chemical Science and more especially to Organic Chemistry bear ample testimony.I would now especially allude to those researches in which he for the first time succeeded in the artificial production of a uegeto-alkali or an organic salt-base ;to his dis- covery of Furfurole and of Renxoline ; no one can peruse his papers upon these subjects which he communicated to the Royal Society and which have a place in the Philosophical Transactions for 1845 without finding ample justification of the view which I have taken of their importance or admitting the just discrimination of that learned body in conferring upon their author the well-deserved testimony of their high sense of his deserts in presenting him with one of the Royal Medals.* Our own Memoirs and Journals are also enriched with his papers on the preparation of an Artificial Yeast on the action of Oil of Vitriol on the Ferrocyanide of Potassium on the preparation of Hippuric Acid on the analysis of South-Sea Guano on the analysis of organic substances containing Nitrogen on the preparation of Ether and on the presence of Phosphoric Acid in the Felspar of Jersey.Of these and other original papers published elsewhere I would willingly have said much more and it would have been a grateful task to me to have enlarged upon their individual merits; but I have already disposed of the time allotted to these matters; I must there- fore conclude with reminding you further that Mr. Fownes was the author of an excellent Manual of Chemistry of which the first edition was published in 1844 and of a third edition of which he had completed the corrections and additions only a few days previous to his death.He was also the author of “An Essay on Chemistry as Exemplifying the Wisdom and Beneficence of God.” This latter production obtained for him at the hands of the Managers of the Royal Institution the Septennial Actonian Prize of 100 guineas ; that body being empowered under certain conditions to award the said prize to such person as shall in their judgment be the author of the best Essay in such department of science as they may select illustrative of the beneficence of the Almighty. * The Philosophical Transactions also contain two other of his papers presented to the Royal Society namely one on the existence of Phosphoric Acid in rocks of igneous origin (Phil.Trans. 1844) and another on the amount of absolute Alcohol in spirit of different specific gravities (Phil.Trans. 1847). 188 PRESIDENT’S ADDRESS. We have lost one other Member namely Mr. Thomas George Tilley. He associated himself with us at a very early period of the existence of our Society and has the honour I may now justly say of having communicated the first paper which was read at our table (April 27 1841) and which has a place in our published Memoirs. It relates to the products of the action of Nitric Acid on Castor Oil. One other paper we also have from Mr. Tilley ‘c On the conversion of Cane-Sugar into a substance isomeric with Cellulose and Inuline,” printed in our Memoirs for 1845. Mr.Tilley who was born at Brentwood in Essex wits not much resident amongst us and I have only been able to collect a very few particulars respecting him. I believe that the foundation of his chemical education was laid at Edinburgh under Dr. Christson he then went to Paris and afterwards studied at Berlin and at Giessen and was made a Ph.D. On his return to England he published an Essay on Agricultural Chemistry and others on the supposed conversion of Carbon into Silicon and of Iron in Rhodium and became in 1845 Professor of Chemistry in Queen’s College Birmingham. About the same time he published a paper on Bebeerine in conjunction with Dr. Maclagan in the Philosophical Magazine. He had not long been resident in this country when his health began to fail and induced him to court the aid of change of air and scene; and after travelling for some time in various parts of Europe he at length took up his abode at Prague.Here we find him working in Professor Redtenbacher’s Laboratory whence his last highly interesting paper on Enantho1 and its compounds is dated and which is published in the Philosophical Magazine for August 1848. It deserves mention as one amongst the abundant instances of the abominations of war that whilst engaged in those investigations the laboratory was ransacked all that it contained destroyed and Mr. Tilley narrowly escaped. Dr. Francis to whom I owe these details says in a letter to our Secretary dated the 27th instant that on his return froin Prague to this country he complained of the state of his lungs and intimated his apprehension of being unable to sustain the vicissitudes of this climate; and it appears that shortly afterwards he repaired to Paris and died in that city.And now allow me to add that this memorandum of our deceased Members necessarily reminds me of the loss which Science has sustained in the course of the preceding year by the death of Berze-lius,-a name justly cclebrated throughout the scientific world and to whom Chemists especially owc a heavy debt of gratitude and of PRESIDENT’S ADDRESS. respect. It is true that his name was not specifically enrolled amongst those of our Members; but his high station his pre-eminent talents and his moral excellence endeared hirn to us all; and I am sure you will join with me in doing what I may call filial homage to his memory.The labours of your Council during the past year have been unusually important and have been directed to objects deeply involving the future condition of our Society. At your last Annual Meeting the Council announced their inten- tion of publishing the Memoirs and proceedings of the Society in the form of a Quarterly Journal with a view of promoting the more speedy and regular circulation of the communications made to the Society amongst its Members; this resolution of the Council has now been carried into effect and four Numbers of the Journal have made their appearance comprising no less than forty-one papers and communications from Members of the Society.These Journals also contain Abstracts and Notices of all the most important papers which have appeared in the course of the year in the several Foreign Journals and an extensive alphabetical list of the Titles of Chemical papers to be found both in the British and Foreign Journals. Among the original papers which have been presented to and read before the Society and which have a place in the Journals of our Transactions there are some of an elaborate description and of great intrinsic importance and which involve difficult and intricate research ; many which are practically valuable from the new methods of mani- pulation which they disclose; and many in which new facts are recorded tending to facilitate the future progress of research upon the several points which are discussed in them.The number of these different communications prevents our adverting more apecifi-calIy to those which we consider most important or making a selec- tion from the new discoveries and methods of investigation which are set forth in them; but we are satisfied that the whole collection is not only eminently creditable to the individuals in whose labours they originate but that they tend to the honour and repute of the Society of whose Transactions they form a part. The Library and Chemical Collection of the Society are making slow but not unsatisfactory progress. In addition to the periodical publications purchased by the Society the following presentations have been made to the Library namely :- PRESIDENT’S ADDRESS.(‘Memoirs of the Geological Survey of Great Britain and Memoirs of the Museum of Economic Geology ;” presented by the Museum. “Report upon the Coals suited to the Steam Navy;” by Sir H. de la Beche and Dr. Lyon Playfair from the authors. ‘‘ Papers on the Colouring Matter of Morinola Citrifolia and on the Distinctive Distillation of Animal Substances ;” by Thos. An- derson M.D. from the author. crAn Essay on the Comparative Value of the different kinds of Coal for the purposes of Illumination ;” by A. Fyfe M.D. by the author. ‘‘A paper on the Chemical Properties of Wax,” from the Phil. Trans. ; by B. C.Brodie Esq. by the author. A paper <‘On the Phosphoric Strata of the Chalk Formation;” by Messrs. Payne and Way by the authors.“Report on the Analysis of the Ashes of Plants ;” by Messrs. Way and Ogsden by the authors. ‘‘ Transactions of the Society of the Friends of Natural Science in Vienna,” and A Collection of Papers upon Natural History <’ by Dr. Haidinger. u The American Journal of Science {’ The Journal of the Franklin Institute ;” “The Pharmaceutical Journal :” by the Editors. (‘A Calendar of the Meetings of Scientific Bodies for 1848-49;” by Mr. Taylor. A lithographed portrait. of Dr. Faraday from a Daguerrotype; by M. Claudet. The following articles have been presented to the Museum namely :-A specimen of the first piece of platinum consolidated from the spongy state in England ; and of the first piece of the same metal soldered with gold by W.T. Cock Esq. A Balance-galvanometer by Mr. W. S. Warde. Specimens of Phosphate of Ammonia and of Arnmonio-phosphate of Soda by Mr. J. T. Herapath. Specimens of Phospho-cerite and of the Oxides of Cerium Lan- thanum and Didymium by Mr. Watts. The state of the funds of the Society will be evident and I trust satisfactory from the Treasurer’s Audited Account which is now lying upon your table. And now Gentlemen having gone through the ordinary businesa PRESIDENT’S ADDRESS. which devolves upon the Chairman at this Meeting it becomes my duty before we proceed to ballot for a President and other Officers to advert to the proceedings of a Special Meeting of the Society which was held here on the 22nd of May last at which Meeting your Council was duly authorized “to take the necessary steps for procuring a Charter of Incorporation on the understanding that the expenses incurred by the funds of the Society should not exceed the sum of $400.’’ I have now the pleasure of informing you that this important and desirable object has been most satisfactorily attained and that under the excellent management and influence of the gentleman who solicited our Charter the whole of the expenses incurred in reference to it amount to the sum of B330 towarda which 33132 have been subscribed by the Members.The actual and prospective advantages thence accruing to the Society are various and important. We now take rank with the other Chartered XcientGc Societies ; and when we consider the zeal and energy which has already been displayed in promoting the views of this Society and their important popular and universal character for who can deny the vast importance of Chemical Science both pure and applied or where can we find a department of knowledge having more immediate bearings upon other sciences upon manufactures upon the common and fine arts upon agriculture upon medicine in short upon the luxuries comforts and necessaries of life ;when I say all these things are considered we may surely reasonably hope and ex- pect that a Society aiming at the most dignified and useful objects and embracing amongst its members many of the most celebrated Chemists of the World will not only prosper but that its resources will increase and its dominion be extended till it vies with any other Scientific Establishment of the country.I therefore thought that we your Council are especially bound to congratulate the Society upon the steps which we have been enabled to take towards in- creasing our stability extending our usefulness and strengthening our claims upon the support and respect of our scientific brethren and of the public at large. One other subject only suggests itself as requiring mention upon the present occasion and it is one which from time to time has engaged the anxious attention of your Council but which each suc-ceeding Session renders more pressing and at present calls for the speediest adjustment which is securely attainable. I mean that having established our name we should next think of a fit local habi-tation and should endeavour to obtain possession not only of a meeting-room capable of affording us adequate and comfortable accom- modation but associated with a room for the reception of our books PREsJ DI:NT’s ADnRE ss.and chemical preparations and also for the meetings of the Council. These desiderata are not easily attainable but they will not be lost sight of by the Council. You will now Gentlemen proceed to ballot for the Officers of the ensuing year and the Secretary will then read the new Code of By-laws which has been prepared by your Council in accordance with the provisions of the Charter of the Society. Of these By-laws there are printed copies upon the table; and we trust that they will now meet with your approval and receive your sanction.And now Gentlemen having completed the biennial period of my service as President allow me on resigning this Chair to MY successor in that honorable office most sincerely to thank you for the distinc- tion which has been conferred upon me and of which I shall always retain a grateful remembrance together with an anxious desire to promote the welfare of the Society. The following Gentlemen were elected OEcers and Council for the ensuing year PRESIDENT. Richard Phillips Esq. VICE-PRESIDENTS. John Thomas Cooper Esq. William Thomas Brande Esq. Thomas Graham Esq. William Allen Miller M.D. SECRETARIES. Robert Warington Esq. Edmund Ronalds Ph.D. FOREIGN SECRETARY. A. W. Hofmann Ph.D.TREASURER. Robert Porrett Esq. COUNCIL. Thomas Andrews M.D. Alfred White Esq. Bence Jones M.D. Lyon Playfair Ph.D. Walter Crum Esq. Edward Schunck Ph.D. William Ferguson Esq. S. Redwood Esy. J. J. Griffin Esq. E. F. Teschemacher Esq. J. P. Joule Esq. Col. Ph. Yorke. The thanks of the society were voted severally to the President Secre- taries Officers and Council for their exertions during the past year. The Charter of Incorporation and the Bye-Laws as revised by the Council to accord with the clauses of the Charter were presented to the Society and it was resolved That these Laws be adopted as the Bye-Laws of the Society. Resolved That the thanks of the Society be given to Mr. Tooke for his friendly services in soliciting the Charter of Incorporation. The following audited Report of the Treasurer was submitted to the Society and the Society then adjourned to April 2nd.

ISSN:1743-6893    

DOI:10.1039/QJ8500200184

出版商:RSC    

年代:1850

数据来源: RSC