摘要:

BLOXAM ON THE ACTION OF XI.-On the Action of Chlorine upon Arsenious Acid. By CHARLESL. BLOXAM. BEING desirous of preparing a considerable quantity of terchloride of arsenic by a more direct method than those usually prescribed for which arsenic itself must first be obtained I distilled a mixture of arsenious acid with strongly ignited charcoal-powder in a cur-rent of washed and dried chlorine. This process furnished very much less than the calculated quantity of terchloride of arsenic and the residue in the retort was found to contain alarge quantity of arsenic acid notwithstanding that a considerable excess of charcoal had been employed. This led me to examine the action of chlorine upon arsenious acid itself. When powdered arsenious acid is very gently heated in a current of chlorine the gas is absorbed a colourless liquid distils over and the powder melts to a perfectly transparent and coloiirless liquid which solidifies to a transparent glass on cooling.On con- tinuing the action of heat and chlorine upon the fused mass it gradually volatilises entirely with evolution of oxygen. Liquid product of the action of chlorine 71pn Arsenious acid- This liquid had all the characters of terchloricle of arsenic. 8.28 grains of it when decomposed by water and precipitated by nitrate of silver gave 19-84grns. of chloride of silver corresponding to 4.9081 grns. of chlorine or 59-27 per cent. Pure terchloride of arsenic contains only 58.67 per cent. On redistilling the liquid almost all of it passed over between 267" and 268"F.* 9.69 grns.of the redistilled liquid decomposed by water and precipitated by hydrosulphuric acid gave 6.52 grris. of tersulphide of arsenic representing 3.9756 gms. of arsenic or 41.02 per cent. 9-79 gms. gave 23-29grns. of chloride of silver representing 5.7616 grns. of chlorine or 58.85per cent. These numbers prove the liquid to be terchloride of arsenic con- taining as might be expected a trifling excess of chlorine * Gmelin states the boiling-point of terchloride of arsenic to be 132"C.(269.6O F.) apparently on the authority of Dumas. CHLORINE UPON ARSENIOUS ACID. 63 Eqt. Calculated. Found. As 75.0 41.32 41.02 C1 106.5 58-68 58.85 181*5 100~00 99.87 The action of chlorine upon arsenious acid may be recommended as a convenient laboratory process for the preparation of tercnloride of arsenic.* Since the solidification of the residue always cracks the retort it is better to employ a Florence flask in which a tufJu-lated aperture has beeu made with the help of the blowpipe to receive the tube delivering the chlorine.With a moderately long- necked flask no condenser is necessary and the terchloride may pass at once into the receiver. 1,000 grns. of dry powdered arsenious acid will be found a Convenient charge and will require the chlorine from about 20 measured ounce5 of common yellow hydrochloric acid and 1,500 grns. of black oxide of manganese. As a slow current of chlorine is required the mixture must be very gently warmed the chlorine being passed first through water and then throiigh oil of vitriol.Arsenious acid yields rather less than one-third of its weight of terchloride of arsenic. Solid product of the action of chlorine upon arsenious acid-Tile vitreous residue cracked in all directions with some violence in tIie act of cooling splitting glass tubes and bulbs containing it and often projecting fragments of them to some distance. Brilliantly transparent when freshly prepared it gradually becatne opaque throughout when kept for a few days like vitreous arseni- ous acid. When moistened with water it became opaque and on boiling gradually dissolved yielding a strongly acid solution which deposited crystals of arsenious acid on cooling. The solution was found to contain arsenic acid arsenious acid and a small quantity of hydrochloric acid.10 grus. of the vitreoiis mass yielded only 0.23 grn. of chloride of silver ropreseuting 0.05 grn. chlorine or 0-5 per cent.? The amount of axsenious acid was determined by dissolving the * It is mentioned by Dr. Miller in his “Elements of Chemistry,” 1864; Part IT.. p. 689 my experiments upon it being then in an incomplete state. 1. Wallace (Phil. Mag. Nov. 1858) obtained a glassy substance by the action of hjdrochloric acid upon arsenious acid to which he assigned the composition ELAsO, iisC13- requiring 10.9 per cent. of chlorine. BLOXAM ON THE ACTION OF glass in solution of potash acidulating with hydrochloric acid and adding a standard solution of permanganate of potash.The result of this determination in several different specimens of the glass showed that the proportion of arsenious acid varied very considerably as might be expected from the difficulty of arresting the action of chlorine at a definite stage. Some experiments were therefore made upon the direct syn-thesis of the glass with arsenious and arsenic acids. At the closed end of a tube of hard glass some arsenious acid was placed arid in front of it a layer of arsenic acid in powdei- the latter was heated to a temperature below its melting-point and after some time the vapour of arsenious acid was driven over it by applying heat to the end of the tube when the arsenic acid liquefied immediately forming a glass similar to that obtained by the action of chlorine.A mixture of one equivalent (99) of arsenious acid with one equivalent (116) of arsenic acid was found to undergo fusion at a far lower temperature than arsenic acid alone but did not form a transparent glass. When two equivalents of arsenious acid were employed the glass was quite transparent. In the experiments recorded in the following table the mix- tures of arseiiious and arsenic acids were heated in bulbs blown in the centre of tubes open at both ends until a perfectly clear liquid had been produced. The ends of the tubes with any excess of arsenious acid which had sublimed mere then cut off thg bulb with its contents weighed soaked in weak potash until the vitreous mass was dissolved off and again weighed to ascertain the weight of the vitreous mass; the arsenious acid was then determined in the solution by acidifying with hydrochloric acid and adding a standard solution of permanganate of potash :-AsOa found in 100 parts.AsOs in eqts. AsOBin eqts. Of the mlxture. Of the glass. employed. employed I* 2 .. 1 63-25 .. 55.30 0. TI 3 .. 1 .. 72.00 .. 61.76 I1I 4 1 .. 77.40 . . 66.34 0. IV 5 1 81.10 .. 63.02 0. 0. v 5 1 .. 81.10 .. 66-63 0. A little arsenious acid sublimed during the fuaion. even in this instance. CHLORINE UPON ARSENIOUS ACID. These results render it probable that when arsenious acid in excess is fused with arsenic acid the compound 2AsO,.AsO (containing 63.25 per cent. of AsO,) is formed though it is difficult to obtain it in a perfectly pure form because the tempera- ture at which it is decomposed is but little above that at which the last portion of the excess of arsenious acid volatilises.After very careful fusion of arsenious acid in chlorine arresting the action as soon as a perfectly clear liquid glass was produced the latter was found to contain 62.38 per cent. of arsenidus acid (2AsO,.AsO requires 63-25). In several of the earlier experiments it had been observed that the period at which fumes of terchloride of arsenic ceased to be evolved at a moderate heat and at which the liquid glass had just become transparent was that at which the glass weighed 88 to 89 per cent. of the arsenious acid employed. according to the equation- 11 AsO + C1 = 2 AsCl + 3 (2As0,.As05) 100 grns.of arsenious acid should furnish 86.2grns. of the vitreous residue containing 63.25 per cent. of arsenious acid whilst the terchloride of arsenic produced should amount to one-third of the weight of the arsenious acid as was in fact the general result of the experiments. For the equation- 8 AsO + C1 = 3 (AsO,.AsO,) + 2 AsCl 100 gms. of arsenious acid should yield 81 grns. of the glass con-taining 46.26 per cent. of arsenious acid whilst the terchloride of arsenic produced would amount to nearly half the weight of the arsenious acid (45 per cent.) The conclusion to which I have been led by the foregoing ex- periments is that the action of chlorine upon arsenious acid at a moderate heat consists in the oxidation of one portion of arsenious acid at the expense of another the arsenic of which is converted iiito terchloride whilst the arsenic acid which has been formed combines with the remainder of the arsenious acid to form a trans- parent glass having the composition 2hs0,.As05 which may also be produced by heating arsenic acid with an excess of arsenious acid. VOL. xv111. P

ISSN:0368-1769    

DOI:10.1039/JS8651800062

出版商:RSC    

年代:1865

数据来源: RSC

摘要:

CALVERT ON A CRYSTALLISED HYDRATE XII1.-On a Crystallised Hydrate of Phenylic Alcohol. By F. CRACECALVERT.F.R.S. F.C.S. I OBSERVED some time since that when four parts of carbolic acid were well agitated with one part of water and the whole exposed to a temperature of 4"C. the sides of the containing vessel became lined with fine large crystals which proved on more carefiil ex- amination to be six-sided prisms of the rhombic system. This new substance was found to be soluble in water alcohol and ether and to melt at a temperature of 16OC. To ascertain its composition some of the crystals were taken and carefully dried betmeeu folds of blotting paper and then submitted to analysis when the following results were obtained :-0.435 of substance gave 0.260 of water or 6-67 of hydrogen and 1.112 of carbonic acid or 69.65 of carbon.In a second analysis 0.488 of substance gave 0.301 of water or 6.85 hydrogen and 1.243 of carbonic acid or 69.5 of carbon. These results correspond in composition to a bihydrate of phenyl or to the ordinary hydrate of phenyl + 1eq. water as seen by the following formulae :-C,2H60.H0 C12H50.2H0 C12H50.3H0. Found. Carbon....,....... 76-59 69.90 64-29 69.13 Hydrogen .... Oxygen ,...,. . . 6.38 17-03 6.80 23.30 7.14 28.57 6.72 24.15 - -I -7- 100~00 m.00 100~00 100~00 The above figiires show that the substance analysed is ordinary phenylic alcohol which has taken an equivalent of water to form a new crystalline compound and what further substantiates this opinion is that when it has been liquified by a temperature above 16"C.and heat is applied it gradually loses water and the boiling point of the liquid rises until it reaches 187"C. the boiling point of phenylic alcohol. This is I believe the first instance of an alcohol uniting with one equivalent of water to form a crystallized hydrate. The only apparent exception with which I am acquainted is the hydrate of propyl-alcohol discovered by Erlenmeyer. I say apparent OF PHENYLTC ALCOHOL. 67 because from the short extracts I have been able to read of his paper it does not appear that he has separated the water which forms the hFdrate of the alcohol obtained by him; in fact the product appears to distil without decomposition. The neutrality of bihydrate ofphenyl on litmus paper as well as that of the ordiuary hydrate led me to enquire if the ordi- nary hydrate should be considered an acid as stated in most of our text-books (as carbolic or phenic acid) or as an alcohol or as a body having some similar properties to glycerin.To decide this point I made the following series of experiments 1 took 100 cub. cent. of solutions of caustic potash having the following specific gravities-1-08 1.03 1-04,1.06 and added successively to ertch of them 25 cub. cent. of the ordinary hydrate of phenyl perfectly pure and having a melting point of 34'C. The following table gives the results observed :-*$363 25 c. c. On adding 25 c. c. of the ordinary hydrate of phenyl to 100 c. c. of solution caustic potash of the above strength the mixtwe 5%a separated into txo layeta-the upper layer consisting of 104 c.c. a GS ...( solution of carbolic acid in alkali and the lower layer of 21.c. c. 88 carbolic acid which has taken up a certain amount of water. 1.02 25 C. C. 25 C. C. On adding aa before hydrate of phenyl to mlution of caustic potash of the above d strength it was not until the addition of the .r( .d 3rd measure of 25 c. c. that the mixture sepa- rated into two layers; the upper layer = 45 c. c., PI and the lower om = I30 c. c. I I 25 c. c. II 25 c. c. In thia instance it required 100 c. c. carbolic acid before Feparation took place when the following results were obtained:-Higher layer = 13 c. c. of alkaline aolution and lower layer = 187 c.c. of acid solution. 26 c. c. 25 c. c. 25 c. c. 11 CALVERT ON A CRYST-4LLISED HYDRATE The above experiments clearly show that the solubility of phenic acid in the alkaline solution is not due to a combination of the acid with the alkali for in that case the quantity of phenylic acid which would have entered into solution would have increased in ratio to the quantity of potash in solution whilst no such ratio exists ad therefore no combination. What further substantiates this view is that if to 100 c. c. of alkaline solution of sp. gr. 1.03 is added successively 25 C.C. of carbolic acid the first two enter into solution but on a further addition of 25 cub. cent not only do they remain undissolved but they separate or carry down with them nearly their own bulk of acid which had been previously held in solution This novel fact of the separation of a substance already held in solution by the simple addition of a further quantity of the same compound proves beyond all doubt that an alkaline solution acts only as a solvent for the hydrate of phenyl and is therefore not a combination of carbolic acid with oxide of potassium.The above table also illustrates another interesting fact viz. that if to a solution of alkali of sp. gr. 1.06 is added successively 25 c. c. of pure carbolic acid no separation takes place; for we were able to add 200 c. c. of hydrate of phenyl without any of it separating. This is due probably to the fact that the hydrate of phenyl takes up a certain amount of water which reduces its specific gravity until it is almost identical with that of the alkaline solution.Further. Two volumes of liquified hydrate of pheriyl were mixed with one volume of concentrated caustic ley and the mix- ture distilled in a retort when 98 O? of the original acid passed over into the receiver whilst the 2 o/o left in the retort was decom- posed into a resinous matter due to the oxidizing action of the alkali upon the carbolic acid. I may state that these experiments were repeated with the bihy-drate of phenyl when precisely similar results were obtained if the quantity of water it contains is taken into account leaving no douht that they are identical bodies with the exception that the new hydrate contains 1 eq.more water not of composition but simply of crystallization. It is stated in our text-books that phenic acid is prepared by mixing the oils of tar which distil between 150°C. and 200' C. with a highly concentrated solution of caustic potash and that the whole on cooling forms a white crystalline mass If we repeat OF PHENYLIC ALCOHOL. this process substituting for the oil of tar pure hydrate of phenyl a white solid mass is also obtained which on being pressed a great number of times between folds of blotting paper so as to remove as neax as possible the whole of the excess of alkali a white crystalline mass is obtained which proves on examination to be crystals of hydrate of phenyl contaminated with a little alkali. Carbolic acid absorbs with great avidity dry ammoniacal gas but no combination takes place for if the mixture is heated the ammonia gas is expelled not a trace remaining in combination with the acid.It is barely necessary to add that if the ammoniacal carbolic acid ia heated in a closed tube water and aniline are produced. Both the hydrates of phenyl when heated with oxide of lead dissolve it and both form a solid compound. These on being well washed with water to remove all excess of phenic acid and dried are found on analysis to have an identical composition viz. C,,H60 + 2Pb0. This compound is slightly soluble in hot alcohol and deposits on cooling. As a solution of both the hydrates of phenyl give with a solu- tion of subacetate of lead a white bulky precipitate (which con-tracts on drying in a remarkable manner remaining as a white amorphous powder) I made the following series of experiments to ascertain if the precipitates which are produced under these cir-cumstances have a constant composition.For this purpose I mixed 200 c. c. of a saturated solution of the ordinary hydrate with 10 c. c. of a solution of subacetate of lead containing 1.614 of oxide of lead. The precipitate produced was collected washed slightly and dried at 110' C, when 1.090 grm. of it gave on cal-cination 0.698 grm. of oxide of lead or 64 % PbO. In another experiment I took the same quantity of carbolic acid dution and added to it double the quantity of subacetate of lead. In this instance the quantity of oxide of lead in 100 parts of the precipitate was equal to 68.2 % showing that in this preci- pitate there was 4 "/o more oxide of lead than in the preceding one and therefore that there is no definite compound formed ; in fact there is so little affinity between hydrate of phengl and oxide of lead that if one of the above precipitates is washed several times with boiling water it loses a large proportion of the hydrate of phenyl.In one instance for example 0470 grm. of the above CALVERT ON TBE ACTION OF SILICATE washed precipitate (dried again of' course at 110 C.) gave on cal-cination 0.393 grm. of oxide of lead; consequently the precipi- tate contained 83.6 % of oxide. There can therefore be no doubt that the hydrate of phenyl like many other organic substances does not give any well-defined compound with oxide of lead.Lastly. Carbolic acid does not decompose alkaline carbonates even under the influence of heat. The small amount of cnrbonate which disappears is not decomposed but merely enters into solution. From the above facts I conclude that what has been called carbolic or phenic acid is a neutral compound and must be re- garded as the hydrate of an alcohol and the new substance de- scribed by me is the bihydrate of the same radical.

ISSN:0368-1769    

DOI:10.1039/JS8651800066

出版商:RSC    

年代:1865

数据来源: RSC

摘要:

CALVERT ON TBE ACTION OF SILICATE XIV.-On the Action of Silicate and Carbonate of Soda on Cotton Fibre. By F. CRACE CALVERT F.R.S. F.C.S. I HAVE lately been engaged in investigating a case of injury to goods which I hope will prove interesting to chemists and manu- facturers from the novelty of the ascertained chemical facts to which the injury is traceable. A large quantity of blue-dipped indigo cotton goods with white reserves were shipped two or three years ago to South Africa and when opened some time after their arrival were found so unsound as to be quite unsaleable the cotton fibres being so much injured as to give way upon the slightest strain. The goods were therefore returned to this country and placed in my hands to investigate the cause which had produced this damage.As a large nnmher of bales were returned without having been opened abroad an excellent opportunity offered itself for selecting a well-defined series of pieces for experiments and also for judging of the effects of packing on goods geuerally when exposed for a long period to the hot and moist atmosphere of tropical climates. Firstly on opening the bales I observed that the boiled-oil cloth which had been employed to protect the goods fromexternal damp yielded when subjected to a very slight strain proving that the texture of the cotton fibre had been injured by the oxidation it had undergone in consequence of its having been saturated with boiled oil. AND CARBONATE OF SODA ON COTTON-FIBRE. Secondly on examining the goods forming the bales it was found in every instance that the outer folds including the second and sometimes the third were stained and dirty but this did not extend deeper the inner folds being perfectly free from stain or mildew.These facts show the importance of returning to this country (where claims are intended to be made upon the manu- facturers or packers) entire and unopened bales of goods instead of a few sample pieces which cannot shorn the state of the bales and enable the examiner to speak with certainty as to the cause of injury. I also ascertained that the rottenness of the fabrics could not have been caused by their having been packed in a damp condition for the hygrometric moisture of a piece in the centre of a bale did not exceed 8.5 per cent.Further the goods were carefully ex- amined to ascertain if any mildew could be discovered which would have occurred if the goods had been packed in a damp state and which would certainly have developed itself more fully in the interior of the bales than nearer the outside if damp pack- ing had been the cause. What completely removed from my mind all doubt as to the cause was that on carefully examining the pieces composing the bales I found among the injured pieces some which were quite sound and on submitting these pieces to analysis comparatively with those which were injured the follow- ing results were obtained The sound pieces left only from 0.55 to 0.65 of ash whilst the injured pieces left 8.29and 8 59 of ash the composition of which was as follows :-No.1. No. 2. Insoluble Silica. ............. 2-94 3.81 Silica combined with soda .... 2.35 2.53 Soda ...................... 1-77 1-60 Other salts.. ................ Sulphate of soda ............11533 Chloride of sodium. ......... 0.65 Sulphate of lead &c. ........ - -8.29 8-59 These analyses show that the pieces had been finished with sili- cate of soda which had undergone a partial decomposition ;while the pieces which left only a few thousandths of ash mere found on further examination to have been finished in the ordinary way viz. with amylaceous substances. This induced me to examine CALVERT ON THE ACTION OF SILICATE more minutely the goods to ascertain whether it was to the sili-cate of soda or to the carbonate of soda arising out of its decom-position that the injury sustained was due; and I was further prompted to carry on this investigation from the fact that at the present time the tendenoy amongst manufacturers is to weight their goods.It is well known that the yisk of mildew is con-siderably increased in proportion to the weight of size; coiise-quently there is a great inducement to use mineral in preference to vegetable substances for that purpose. I therefore trust that the results now published mill warn manufacturers of the risk they run in using mineral size without great care and experience whilst on this point I may be permitted to give here an insight into the nature of the size often used in Lancashire for sizing the warps of grey calicoes and therefore I give a few of the results obtained at my laboratory.Aaalyses of Various Cloths. No. 1. Mineral matter principally clay and aul-phate of magnesia.. .. .. .. 5-2 Water in excess .. .. .. .. 8.8 Fermented flour .. .. .. . . 10.0 Hygrometric moisture .. .* .. 8-0 Fibre . ** *. .. ** .. 74.0 1oooo No. 2. Mineral matter principally sdphates of baryta and magnesia .. .. .. 4.5 Water in excess .. .. .. . . 2.1 0. Fermented Flour .. .* .. 11.3 Hygrometric moisture . .. .. 8.0 Fibre .-.. .. .. .. .. 74.1 100.0 No. 8. Mineral matter principally sulphate of soda and clayFlour . . .. .. .. .* .. 0. .-e. . e. 4.8 10.0 Water in excess . .. s. .. 4.5 Hygrometric moisture Fibre ..0. .. . .. e. .. .. .. 8.0 72.7 lOO*O AND CARBONATE OF SODA ON COTTON-FIBRE. No. 4. Mineral matter .. .. .. .. '1.24 0. Water in excess .. .. .. 1.74 Fermented flour .. .. .. .. 13-02 Hygrometric moisture .. .. .. 8.00 0. Fibre. . .. .* .. .. 76.00 100~00 Tne above data show that warps are sized with sour flour (viz. flour which has been allowed to ferment for several days or weeks) and various mineral matters to the amount irrespective of moisture of about 15 per cent. There can be no doubt that goods thus sized are extremely liable to mildew owing on the one hand to the use of fermented flour or organic matter in a state of decay and on the other to the use of clay which tenaciously retains moisture which facilitates cryptogamic vegetation when the goods are packed.I may state en passant that sulphate of magnesia sulphate of lime sulphate of baryta sulphate of soda and the chlorides of sodium and magnesium are often used with or without clay as weighting materials. On examining the comparative streiigth of various pieces composing a bale I observed that the outside folds of the pieces which formed the external parts of' the bale (above alluded to as dirty and stained) were comparatively strong when tested against the folds of the same piece which were towards the interior of the bale. I therefore took the same weight of cloth from both classes of folds and submitted them to analysis with the following results :-Interior of Exterior of bale.bale. Insoluble silica ,. .. .. 4.81 7.08 Silica combined with soda .. 2-53 0.20 %. Soda .. .. .. 1.60 0.47 Other salts .. .. .. 0.65 0.55 -8.59 8-30 On examining and comparing these figures it is at once seen that the stained fold shows a large increase in the amount of insoluble silica and a corresponding decrease in the amount of silica combined with soda ; but notwithstanding this the total amount of silica is nearly the same in both classes of cloths. CALVERT ON THE ACTION OF SILICATE Further that there is a total disappearance in the stained fold of 1.13 o/o or more than two-thirds of the total amount of soda. From these results it would appear that the silicate of soda when first applied to the goods coiitained the whole ofits silica in com-bination with the soda and that under the inffuence of the carbonic acid of the atmosphere the silicate of soda has been decomposed into insoliible silica and carbonate of' soda thereby giving rise to great increase in bulk j whilst in the goods which were protected from an excess of moisture-as towards the interior of the bales,-a.nd also from the action of carbonic acid there is only a partial decomposition of the silicate of soda Mr.Walter Crum has kindly suggested and I believe the view to be correct that the cotton fibre has by its organic nature a cohesivc attraction for silica which enhances the decomposition of the silicate of so&a employed to finish ad weight the goo&. From these facts we may assnme that there were two destruc- tive influences brought to bear upon the cotton-fibre-lst that of the increase of' bulk resulting from the decomposition of the silicate of soda giving rise to the formation of free silica and carbonate of soda which exercised a dishending and disiutegrating action upon the cellular tissue of the cotton fibre causing it to burst and necessarily weakening its tensile strength ; 2nd the direct and destructive action of the free carbonah? of soda upoii the fibre.The latter appears to be the principal cause of injury for in the external folds we have a more complete decomposition of the silicate as shown in the above figures by the increase in the amount of insoluble siIica and at the same time a decrease of the soda amounting as previously stated to more than two- thirds of the total weight.MTe shall now trace more in detail this interesting decompo:;ition of silicate of soda and endeavour to show what had become of the soda which had disappeared. To attain this object a complete series of specimens were obtained from an entire bale viz. 1 a piece which formed the outside and was stained; 2 some of the paper employed in wrapping the goods which was in immediate contact with the stained cloth; and 3,some of the flax wrapping placed next to the paper and between the latter and the oil-cloth covering above alluded to. The following are the results yielded by analysis :- 75 AND CARBONATE OF SODA ON COTTON-FIBRE. Pieces of Goods. Paper Wrapping.Flax Wrapping. -L-? /-No. 1. No. 2.’ ”0.. 3. No. 4. No. 5. No. 6. inside outside in not in in not in fold. fold. contact contact. contact. contact. Insoluble silica. . 4.05 5.65 0.02 0.03 0.04 0.01 Silica combined with soda. . 2-21 0.38 0.09 0.02 0.08 0.03 Soda.. ........ 1.76 0.25 0.85 0.01 0.29 0.02 Other substances 1.96 1-91 15.15 15.213 1.19 1.25 ---I_ Total ash.. . . 9.98 8-19 16-11 15.34 1.58 1.31 In examining these results we have again a most striking and marked difference in the amount of insoluhle silica and soluble silicate of soda in the two different parts of the same cloth; and further where the carbonate of soda has been removed the folds of the cloth remain comparatively sound. As to the paper wrap- ping it is evident that the paper in contact with the goods has absorbed a great part of the soda which was previously combined with the silica and that the sods is partly in the state of carbonate and partly in combination with some of the organic matter of the brown paper; for when some of the paper was treated with water it yielded a yellowish brown substance which coloured the liquid whilst the part of the same paper which had not been in contact with the goods did not discolour water in any marked degree.Purther the aqueous solution was neutral and not alkaline as in the previons case. As to the Bas wrapping the same difference as noted in the paper was observed viz. that the part of the wrapping in contact with the stained paper and the stained fabric contained carbonate of soda whilst that which was in contact with the clean paper contained only a trace.In looking over the bales a piece of cloth was found which had been finished with silicate of soda and was partly overlapped by another piece showing one half of its exterior fold stained and compara- tively sound whilst that half of the fold which was prevented from forming the exterior of the bale by being overlapped by the previous one was quite tender and rotten though it showed no signs of any stains or mildew. I also examined a sound piece which had lain in contact with an injured one and found that in those folds which had been in contact there was in the injured piece less soluble silicate and in the folds of the sound piece a considerable quantity of carbonate of soda the presence of which could not be found in the folds forming the centre of it CALVERT ON THE ACTION OF SILICATE ETC.Having observed that the reserved white patterns of the blue- dipped Indigo cloth were a great deal more tender than the blue portions of the same piece I carefully cut out a portion of the white parts and submitted tliem with the blue parts to analysis with the following results :-White. Blue. Insoluble silica .. .. .. 5.48 3-17" Silica combined with so da. . .. 0.18 2-10 Soda.. .. .I .. .. 0.78 1-43 Other salts .. .. .. .. 1-08 067 -7 Total .. .. .. .. ;*52 7-37 These figures illustrate the fact that the decomposition of the silicate of soda has been carried on to a much greater extent in the white parts than in the blue; and I am led to believe that the cause of the iucreased rottenness in the white is due to the printer having used a resist-paste too acid and having found that the whites were slightly teiidered he endeavoured to check the further action of the acid on the cotton-fibre (which as chemists well know continues until the cotton fibre is completely destroyed) by the employment of a strong solution of silicate of soda which being an alkaline salt was well adapted to neutralise any acid in the cloth and arrest its action.And as previously only weak solutions of silicate of soda had been employed for this purpose the printer of these goods could not have foreseen that the use of a more concentrated solution would result in such serious conse- quences.The above figures also prove another interesting fact viz. that the white parts of the cloth contain a much larger pro-portion of silicate of soda than the blues thus proving that the dyed indigo fibres being partially filled mith this resinous dyeing material were not in a condition to absorb so largely the silicate of soda. Messrs. H. Car0 & Dancer who were also employed to investi- gate this matter entertain a different opinion as to the cause of the white parts being more injured than the blues. These gentlemen are led to believe from their results that the reason why the whites are more injured than the blues is that a slow chemicalactionhas ensued between the sulphate of lead reiiiaining from the reserve paste and the silicate of soda and that a silicate of lead has been formed and as this salt occixpies a larger bulk than the sulphate of lead previously existing in the fibre the production of it inside the cellular tiysuc of the film has been the cause of thc increased CHURCH ON SOME HYDRATED CUPEIC OXYCHLORIDES.77 tenderness of t.he whites. But as these gentlemen are engaged in investigating the question more fully Ishall leave to them the pleasure of publishing their results. Lastly I deemed it my duty to make some direct experiments on the action of silicate of soda on cotton fibre. I therefore took some white cotton and dyed a portion of it with indigo. This blue-dyed cloth with a part of the white one were dipped in a moderately strong solution of silicate of soda then dried and a portion of them introduced into a bottle at the bottom of which a little water had been placed and to help the action of the car- bonic acid of the atmosphere a slow current of carbonic acid was then passed through the bottles containing the cloths.After three months time the warps of these samples were tested and their comparative breaking weights were found to be as follows :-On an average of 10 essays. The warps of the unsilicated cl oth dyed blue ,.. 3~4 The same silicated .. .. .. 8. D* 289 These results leave no doubt that the warps even during the short period of three months had been considerably injured by contact with silicate of soda. In conclusion I beg to add that I am aware thet silicate of sodahas been used for finishing coloured goods but when employed it has been in a very.dilute state and therefore its destructive action has not been sufliciently marked to draw the attention of calico printers.

ISSN:0368-1769    

DOI:10.1039/JS8651800070

出版商:RSC    

年代:1865

数据来源: RSC

摘要:

CHURCH ON SOME HYDRATED CUPEIC OXYCHLORIDES. 77 XV.-On. some Hydrated Cupric Oxychiorides from Cornwall. By A. H. CHURCH,MA. Professor of Chemistry B.A. College Cirencester. 1 HAVE lately received from Cornwall a copper mineral which proves to be new. Qualitative analysis of the specimen shewed it to con-tain chlorine copper and the elements of water ; very precise test- ings subsequently revealed the presence of traces of carbonic acid arsenic aluminium and sodium ;but these substances exist in most minute proportion in a carefully selected sample-indeed their quantity is too insignificant to admit of estimation. CHURCH ON SOME HYDRATED The colour of the new mineral is bright blue slightly inclining to green (turquoise-blue) ; it occurs in thin crusts consisting of irregular aggregations of minute globules which present a botry-oidal appearance under the microscope.The globules are dis- tinctly subcrystalline and subtranslucent. The hardness of the mineral approaches 3 ;its density has not been determined with exactness but it is about 3.5. The streak of the new mineral is white; it is extremely fragile. It is insoluble in water but quite easily soluble without residue even in dilute acids and in ammonia. It is hygroscopic when kept in dry air it loses some hygroscopic water without change of colour but it rapidly becomes green at loo" acquiring a tint similar to that of atacamite this change of colour is accompanied by a further and considerable loss of water. On ignition the cupric chloride volatilizes in part ;the final residue is of a dark olive-green tint.Fm analysis the mineral was dried in vucuo over oil of vitriol until it ceased to lose weight 3 the sample had been most care-fully selected in order that the results of the analysis might be completely free from the disturbing inflfience due to any impuri- ties ; for under the microscope it was seen that the botryoidal or pisolitic crusts although constituting the hulk of the mineral were accorripariied by traces of foreign salts. These salts were calcic sulphate," ferric oxide &c.; the latter oxide being also the matrix of the mineral. The following are the analytical details :-I.-1.185 grammes lost in vacuo -055 gramme water. II.-1.13 grammes gave *505gramme chloride of silver.111.-598gramme gave *251gramrue chloride of silver. IV.-1.13 grammes gave .718gramme cupric oxide. V.-*752gramme gave ,499 gramme cupric oxide. V1.-405 gramme gave -268gramme cupric oxide. A third determination of chlorine mas made in another sample which was less piire containing compouiids of cslciiim arid iron in more than mere traces. Not haviug the requisite data for cor-recting the result I have omitted it relying upon the numbers above given the accuracy of which I have no reason to doubt. The greater part of the single specimen of' the new mineral mas * A eomplete analysis of Connellite a cupric aulphato-chloride (from Corn-lvall) is greatly to be desired. In the outer blue layer or crust of our mineral itself a trace of snlphuric acid was found but 212 rnilligrammes gave 2 milli-grammes only of barium-sulphate.CUPRIC OXYCHLORIDES FROM CORNWALL. consumed in these analyses for some of which I took as will be noticed an unusually large amount of substance in order to lessen the effect of any errors of manipulation.* Translated into percentages the experimental results are as follow :-I. Hygroscopic water lost in vacuo .. 4.64 p.c. 11. Chlorine . . .. .. .. 11.05 p.c. 111. Chlorine .. .. .. IV. Cupric oxide . .. V. Cupricoxide .. .a VI. Cupric oxide .. .. To what formula do these percentages correspond? There is but one native hydrated cupric oxychloride-atacnmite but it contains more chlorine than $he salt now under review.Ata-camite Seems often to have the composition expressed by the formula :-CuC1 3CuH202.aq. ; sometimes it has a smaller percentage of water sometimes it is more highly hydrated. The formula which furnishes proportions most nearly approaching to the blue oxychloride is- as the following comparison of the theoretica4 and experimental percentages will shew :-Theory. Experiment. CuCl,. 4CuH202. 4ag. mean. ZC1 .... 71-0 .. 11-91 or 11'91 11.33 cu.., 63$ .. '*"' 1 66.6OCuO 66.24 4CuO .. 318.0 .. 53-29 8H20 .. 1440 .. 24.16 24-16 --3 596.5 100°OO 102.67 The new mixiera€ thus differs chemically from the allied species atacamite in a most urnistakeable manner. Not only is it more highly hydrated but it contains the cup& cliloride and cupric hydrate in different proportions.f A special determination of impurities zinc-oxide &c. was made in one instance ;they amounted to -75 per cent. on the vacuum-dried mineral. 80 CHURCH ON SOME HYDRATED CuC1 CuH,O Atacamite 1 3 New species 1 4 The physical characters of the two minerals are also as I have already remarked very distinct. A few words as to the water in the mineral may not be out of place here. Crystallized cupric chloride is green and has the formula CuCl2.2aq. When this salt is dissolved in some quantity of water it becomes blue; just 30 the less hydrated mineral atacamite is green; the more hydrated new species is blue. So also with the blue langite and pale blue lyellite as compared with the green brochantite.Atacamite.. ,. CuCl . 3CUH,02 aq. green. New species.. CuCl . 4CuH,02 . 4 aq. blue. Brochantite .. 2Cu80 . 5CuH,O green. Lan@te* .... CuSO; . 3CuH,O,. aq. blzle. Lyellite. ..... .3Cu,H,02 . 3 aq. blue. The following details concerning the atacamite recently de- tected in Cornwall are given in part for the sake of comparison. These are the results on analysing an extremely pure spe-cimen :-1. 11.24 grains lost 27 grains in vacuo. XI. 11-98 grains lost 2.05 grains at 270°C. 111. 11-24grains gave 6.07 grains AgC1. IV. 12.8 grains gave 7-1 grains AgCl. V. 11.24graius gave 7-85 grains CriO. VI 11-33grains gave 7.89 grains CuO. The formula CuCl . CuH,O .aq. demands the following per- centages :-2Cl .... 71.0 15-97 or 15.97 cu .. .. (33.5 '''%171-43 Ct10 3CuO -. 238.5 53.58 4H,O .. .. 72.0 16.19 16.19 445.0 LOOoOO 103.59 These are the percentages deduced from the foregoing analyses of atacamite :-* Or for the sake of more ready comparison with brochantite langite may be represented thus 2CnS0,.6CuH2O2.2aq. CUPRIC OXYCHLORIDES FROM CORNWALL. Hygroscopic water lost in vacuo . . I. 2.40 P.C. H20 lost at 26OoC .. .. 11. 17.11 p.c. or c1 .. 111. 13-35 p.c. c1 .. .. IV. 13.70 p.c. CUO .. .. V. 69.84 p.c. CUO .. .. VI. 69-34! p.c. Analysis 11. does not represent the percentage of water in atacamite accurately It was observed that this mineral does not lose water alone when heated in the oil-bath to 260' C. Hydro-chloric acid is also evolved while a part of the water is yet obstinately retained even at the temperature at which cupric chloride begins to be given off.The numbers deduced from Analyses 111.to VI. require a correction to be made in them for hygroscopic water (see Anal. 1.j before they can be compared with the theoretical percentages :-Experiment.(Nean corrected p.c ) Theory.(CuC1,.3CuH20:.aq.) c1 0. .. 15'20 15.97 CUO .. .. 71.31 71-43 H20 .. .. - 16.19 103*59* The deficiency in the experimental and calculated chlorine and cupric oxide is most probably due to the hygroscopic water not having been absolutely removed by desiccation in vacuo over oil of vitriol ; its influence has consequently been under estimated. The proposed formula agrees more nearly with the results of analysis than the expressions usually adopted for the several varieties of atacamite :-CuC1,.3C uH ,Q CuC1,.3CuH20,.l~aq.CuCl2.3CuH,Q,.2aq. CuC1,.3CuH20,.3aq In all these formulse however the proportion of cupric chloride to hydrate is maintaiiied constant. It is worthy of note that not only have several varieties of atacamite been prepared artificially but that a compound corresponding to the salt described in the * The whole of the copper is calculated as oxide part being in fact combined with chlorine. VOL. XVII I. G CHURCH ON SOME HYDRATED first part of the present communication has been obtained by Kane and by Graham by the action of water on the com- pound CuH,N,C12 :-Kane’s Salt.. .. .. CuC1,.4CuH202.2aq. New Cornish mineral .. CuC1,.4CuH20,.4aq. The atacamite from Cornwall (St. Just) occurs in a variety of forms. The mineral is sometimes found as hollow stalactitic tubes the concentric layers of which are almost transparent. Sometimes it appears in semicrystalline crusts more or less dis- tinctly stratified and having a rippled surface. The proximity of the copper mine in which the mineral is found to the sea and the detection of sodium and magnesium salts in the atacamite itself point to the mode of its formation. I am indebted to the kindness of Ah. R. Talling of Lost-withiel for all the minerals mentioned in the present note. Notes to the foregoing paper.-Some indications of the existence of another cupric oxychloride more basic than the new species described have been observed Until additional specimens have been met with it would however be premature to make any posi- tive statements on this point.The new oxychloride is not affected by boiling with water. No cupric chloride enters into solution nor is the colour of the mineral altered. An intimate union seems to exist between the ciipric chloride and hydrate in the new mineral. Its formula (omitting the 4aq.) might perhaps be written on a mixed HC1 and H,O type (2HC1 + 8H,O) I have mentioned that the new oxychloride contains a trace of some sodium-salt. It seems to be the chloride and is removed by washing the mineral with hot water. The quantity is trifling. 511 milligrammes of the finely powdered mineral gave by this treatment but 3 milligrammes of silver chloride.I deemed it a matter of some interest to determine the chlorine in the mineral thus washed. Accordingly a portion was dried over oil of vitriol in VQCUO till it ceased to lose weight. Of this preparation ,353 grammes gave ~17 grammes silver chloride. This quantity CGPRIC OXYSULPHATES FItOM CORNWALL corresponds to 11-91 per cent. of chlorine exactly the proportion demanded by the formula I have adopted. All the insoluble basic cupric minerals already alluded to if finely powdered dissolve easily in dilute acids. On this property might be founded a method of volumetric analysis the ratio of chloride (or sulphate) to hydrate being I believe thus ascertainable. Postscript March llth 1865.The new oxychloride occurs in the Botallack mine. Thanks are due to the captain of this mine ah. Hockin for his obliging courtesy. Mr. Talling has now found and forwarded to me a further supply of the new blue oxychloride. Some of the specimens are on quartz. One of the new specimens gave the following results on analysis (substance dried in vacuo) 0264 grm. gave -175 grm. CuO = 66.29 p. c. -3555 grm. gave -235 grm. CuO = 66.10 p. c. Theory demands 66.60 per cent. The chemical and physical characters of this species are therefore constant as well as distinct.

ISSN:0368-1769    

DOI:10.1039/JS8651800077

出版商:RSC    

年代:1865

数据来源: RSC

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CGPRIC OXYSULPHATES FItOM CORNWALL XVI.-On some Hydrated Cupric Uxysukhatesfrom Cornwall. ByA. H. CHURCH. ZyeZlite.-Not very long after his announcement of “Larzgite ’’ as a new mineral species from Cornwall Prof. Maskelyne pointed out. a second copper compouud from the same locality as distinct. This species he termed “Lyellite.” Three months later 35. Pisani gave an analysis of the same mineral; it will be found in the Comptes Rendus of Nov. 14th 1864. M. Pisani re-names the mineral ‘‘Devilline,” and deduces for it the formula :-(CuCaFe),S + 3aq. I purpose to employ the name Lyeltite as having priority. I have received from Mr. Talling a portion of the same speci-men of lyellite as that analysed by M. Yisani and have submitted it to analysis. It is unnecessary to repeat in detail the physical and chemical characters of this new species of Prof.Maskelyne’s; it will suffice to say here that the analysis of this mineral presents CHURCH ON SOME HYDRATED some peculiar difficulties. For intermixed with the true lyellite which occurs in concretionary crusts of a very pale bluish white tint and satiny lustre is a darker blue mineral apparently langite. This impurity occurs in layers and is irregularly dis- tributed in the whiter mineral ; these layers are sometimes in the direction of the radiation sometimes across it. Fortunately the blue mineral being in loosely coherent masses of minute crystals may be almost completely removed by breaking the mineral into small fragments and carefully brushing these with a fine sable pencil.In this way my specimen was prepared for analysis but it was not quite pure even then. I believe the only impurity was the blue mineral and assuming this as is most probable to be langite the discrepancies between the theoretical and experimental percentages are explained. Lyellite contains copper calcium a sulphate and the elements of water. It contains also a minute trace of iron so minute as to give no distinct reaction when a few grains of the mineral in solution were tested with potassic ferri- cyanide; and even after oxidation the ferro-cyanide gave a faint blue coloration only. The following are the results of the analysis of lyellite :-03245 gramme lost in vacuo 0002gramme H,O -3225 , gave 0184 , BaSO 03225 , > 0045 , CaCO 03225 , ,> -165 , CuO These numbers correspond to the following percentages :-Hygroscopic water $62per cent.23.50 ,, so3 CaO. 7-81 , CUO. 51.13 , I have said that M. Pisani proposes for this mineral the for- mula-(CuCaGe),S + 3aq. We have however seen that it contains no iron and the results of my analysis which agree closely with those obtained by M. Pisani correspond to a slightly modified formula. Annexed are the theoretical and experimental percentages. CUPRIC OXYSULPHATES FROM CORNWALL. Theory. Experiment. (CuCa2S04.3CuH202.3aq.) Pisani. Church. 4CuO .... 318 49.53 51.01 51.13 CaO .... 56 8-72 7.90 7.81 2S03 .... 160 241.90 23.65 23.50 6II,O .... 108 16.95 16-60 16.88 (by diff.) 64.2 lOO*OO 99.16 0.68 (impurities).FeO 2-77 100.00 101.93 It will be observed that the cupric oxide is in excess while the calcium-oxide and sulphuric anhydride are deficient ;the assumed admixture of the lyellite with a mineral evidently (from its deeper blue tint) richer in copper will account for all these discrepancies- a very small percentage of langite would in fact produce this result. Brochantik-A mineral which appears to have the chemical characters of brochantite has been lately found in Cornwall. M. Pisani announced this discovery in the Comptes Rendus for Nov. 28th 1864. Several formulae have been proposed for the native and the artificial brochantites but it has been remarked that this basic sulphate oscillated between- CilS0,.2CuH,02 and CuS0,.3CuH202 ; my analysis points in the same direction; it suggests however the intermediate formula- 2CuS0,.5CuH202.Before giving the analytical results it may be stated that the brochantite often accompanies langite the latter mineral being then seen as a scattered blue crust upon the dark green or emerald-green brochantite. I fear that the crystals in my specimens are too small and confused for accurate measurement. They are transparent and occur in groups of slender wedges tapering tow:uds either extremity. Two of the boundaries of each crystal appear curved. Since my preliminary note on Cornish brochantite appeared in the Chemical News (Feb. loth 1865) this mineral has been described under the name of Waringtoni te by Professor M ask e 1 y n e ; it is unnecessary therefore to repeat here the physical characters of the substance; I will merely give the analytical results and the formula they CHURCH ON SONE HYDRATED suggest.It ought to be stated that the utmost care was taken to obtain a homogeneous sample for analysis. The brochantite occurs upon decomposing elvan but immediately underneath the cupric crust a considerable quantity of ferric oxide occurs. An impure cuyreous wad also occasionally accompanies the brochantite. 6.73 grains lost *07grains at ,260' C. 5.17 , gave -03 , insoluble residue 5.17 , , 2.85 ,) BaSO 6.73 , , 4.62 ,) CuO 5.17 , , 3.51 , CuO. Before the mineral was submitted to analysis it was placed over oil of vitriol in vacuo; but by this treatment it suffered no appre- ciable loss.Below are given the percentage numbers deduced from the foregoing analyses. In the first column the percentages are those deduced directly; in the second column the calculations have been made after subtraction of the water lost at a temperature not exceeding 260° C.,* and of the insoluble matter :-CuO. ................ 68.27 69-32 SO .................. 18.93 19.24 H,O.. ................ 11.18 11.44 H,O lost below 260' .... 1.04 -Insoluble matter. ....... *58 100-00 100~00 The formula 2CuSO4.5CuH,O, requires percentages closeIg corresponding with those deduced from the analyses :-Theory. Experiment CUO.. .... 69.00 69.32 SO,. ..... 19.84 19.24 H,O. .....11.16 11.44 The differences it will be observed all lie in the diivection of the probable experimental errors. In an analysis not recorded above 6.73 grains of the mineral gave 8-39 grains of BaSO ;this corre- sponds to 17.3 per cent of SO,. But with the lower estimate of the SO, the total percentage of water in the mineral calculated by difference amounts to no more than 13.48; in the second analysis it is only 1.2.6. These numbers exclude the formula CuS0,.3CuH,02.aq. which demands 15.34 p.c. H20 as the fol- lowing comparisons show. It must be remembered that the * Some specimens lose nothing at thiB temperature. CUPRIC OXPSULPIIATES FROM CORNWALL. mineral under review loses sulphuric acid as well.as water when heated sufficiently to deprive it of all water; the water in it is retained even at 260"-270°C.f 1. Theory. 11. 111. ' F I. Experiment. J-11. 111 Cu304 3CuH,02. CuSOl 2CuS04 3CuH20-aq. 5Cu H,02. Pisani. Msskelpe. Church. CuO . . 70.36 67.62 69.00 70.06 68-24 69-32 SO . . 17.70 17-04 1984 17*52 16.73 19.24 H20 . . 11.94 15.34 11-16 13.42 14.64 11-44 Collating the recent with the older analyses of Brochantite,* there seems some ground for the opinion that at least two sub- stances chemically distinct have been included under one name. If such be the case Prof. Maskelyne's Waringtonite might be separated chemically as well as crystallographically from Brochan- tite although his proposed formula (11.above) is negatived by both of my analyses and as well as by those of M.Pisani. One hesitates indeed between the formul2e I. and III. but it is pos-sible that M. Pisani may not have analysed the true xedge- shaped crystals of so-called Waringtonite but the commoner form of Brochantite occurring in the same locality. For the analysis of the variety or species Waringtonite I am indebted to my assistant Mr. R VC'arington junior. Langite.-According to M. Pisani langite has the formula CuS0,.3CuH202. ag. the very expression assigned to Waring-tonite by Prof. Maskelyne. My own results confirm those of Af. Pisani. A few words are necessary as to the material sub- mitked to analSsis. Langite appears both in miniite prismatic crystals of a fine blue colour and also as a foliated crystalline mass. The latter form is the more abundant and having freed some specimens of it from a few imbedded crystals of the deeper colour I submitted them to analysis with the following results :-a.1-024 gramme lost in vacuo -004gramme H20 Air 1.024 , gave ,691 , CUO 9, dried. { 1.024 , -501 , Bas04 6. 14.09 grains lost at looo C *12 grains H20 Vacuum 14.09 , below redness 2.29 , H20 dried. i14.09 , gave 6.86 , BaSO * Rammelsberg's Minerakhemie (1860),p. 268. CHURCH ON SOME CUPRIC OXYSULPHATES. C. 12.3 grains gave 8.35 grains Cuo 1000 c. I made the analyses of a; b and c were analgsed by Mr. War-ington. The following are the percentages deduced from the several analyses calculating the results on the vaconm-dried sub-stance and also on the substance as dried at 100°C.:-Dried in vacuo. Dried at 100°C. A. H. C. R. \V. R. W. CuO .. 67.48 67.31 67-88 SO .. 16-79 16-72 16.88 H,O .. 15.73 16.25 15.53 100~00 100.28 100.29 These nurn hers correspond very closely with those required by the formula CuS0,.3CuH20. aq. :-Mean (vacuum dried). 4CuO .. 318 = 67.65 6740 so .. 80 = 17-02 16-76 4H,O .. 72 = 15.33 15.89 470 100*00 100.05 The results of independent analyses by M. Pisani Mr. W aring-ton and myself are so exactly accordant that there cannot be the slightest doubt that the blue folk said to be langite are definite in composition and that the formula expressing the com- position of the mineral is CuS0,.3CuH,02.aq. All the slight differences between the theoretical and experimental percentages lie in the direction of the several probable errors; and the loss of water in vacuo amounting to no more than -39 per cent.it canuot be said that the mineral has been altered by the method of desic-cation adopted. The total amount of impurities in the mineral was found by experiment to be very insignificant yet if allowance had been made for it a still closer coincidence between theory and experiment would have been shown. It is scarcely necessary to add that all the analyses recorded in the present paper were performed with the greatest care; the reagents mere pure and the methods known to be trustworthy.

ISSN:0368-1769    

DOI:10.1039/JS8651800083

出版商:RSC    

年代:1865

数据来源: RSC

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WAN HLYN ON VAPOUR-DENSITIE8. XVII.-On Vapour-densities. By J. ALFREDWANKLYN IN having recourse to a vapour-density det2rmination for the purpose of settling a chemical formula chemists are in the habit of preferring determinations made at a high temperature to those made at a low temperature. And yet they do not adhere to this principle with steadiness; far no one would think of preferring a vapour-density determination of alcohol above the boiling point of mercury to one at the boiling point of water. Chemical com-pounds are decomposed at high temperatures and organic compounds especially. When the vspour-density at a low tempe-rature differi from that at a high temperature what is to show that the difference is not an effect of decomposition and that the data obtained at high temperatures are of more value than those of a vapour-density determination of alcohol taken at tempera- tures above the boiling point of mercury ? Looking at the matter from this point of view one would be inclined to reverse the maxim which has found favour with chemists; and to direct that a vapour-denBity determination if it is to be employed for the construction of a formula should be taken at the lowest temperature that is practicable.The reason which has induced chemists to run the risk of decomposing their vapours before measuring them (a risk which is very real) is the fear that vapours are not sufficiently gaseous at low tem-peratures. On the present occasion I will examine the grounds of this fear. The results flowing from the accumulated labours of chemists in thi3 direction may be summed up as follows :-(1).Of a thousand vapuurs which have been experimented upon all exhibit a density often almost identical with and seldom de- parting from the theoretical density by more than about -1 or a2 when the determination is made at not less than 40" C above the boiling point of the corrcsponding liquid.When the determina- tion is niade within about 10" C. of the boiling point of the liquid the vapour-density determination is *1 or -2 higher than that at 40" C. above the boiling point. (2). Some few substances such as sulphur and acetic acid haa\re YOL SVIII. €3 WANRLYN ON VAPOUR-DENSITIES. vapour-densities which taken at 40" C. above their boiling points depart from the theoretical numbers by units instead of by tenths.On heating the vapours of some of these substances still higher they become of the theoretical value in some instances,-in other instances not. (3). Some substances a vapour-density determination of which has been sought at 40" C. above the boiling point give irregular numbers and are known to decompose. Respecting this last class of substances nothing need be said. Con-cerning Class (1) the remark may be made that the circumstance that when no decomposition occurs a determination made by the usual methods at 40" C. above the boiling point is better than one at only 10" C. above the boiling point does not prove that accurate determinations cannot be made at within 10" C.of the boiling point if certain precautions be adopted. On a former occasion I have pointed out that therk is nothing magical in this elevation of 40" C. but that 40' C. of super-heating of the vapour-a condition which can be attained otherwise than by actual elevation of the temperature to 40" C. above the boiling point of the liquid-is the ewsential condition for vapour-density purposes. This conclusion which is a very natural and obvious deduction almost evident a priori has been tested by direct experiment. Dr. Playfair and the author selected a number of substances at raudom converted them into vapour superheated the vapour not by raising the temperature but by depressing the pressure (or what comes to very nearly ihe same thing by mixing it with a certain volume of a permanent gas) and got accurate determina- tions of vapour-density at temperatures even below the boiling point.Cahours' maxim "heat your vapour 40' C. above the boiling point of the liquid," when emended into ''superheat your vapour 40°," is quite compatible with the recommendation to "make the determination at the lowest temperature that is practicable." Touching the slight increase in the vapour-density when instead of 40" C. of superheating there are only 5" C. or 10' C. it is not so much due to any alteration in the co-efficient of expansion as to condensation on the walls of the vessel which is used to con- tain the vapour.* Of Class (2) (the most prominent members of which sulphur * Certain expPriments male by Magnus show that the effect due to thiB cause must be very considerable.WANKLYN ON VAPOUR-DENSITIES. and acetic acid evolve vapours irregular in their density at low temperatures but regular at high temperatures) the ohservation may be made that there are good grounds for believing decompo- sition to occur in each individual case. One needs but to glance at the ply-sulpbides to be couvinced that sulphur is very prone to combine with itself and so to produce complex sulphur of different molecular weights. The existence of the allotropic modifications of sulphur points undeniably in the same direction. If we did not kriow that when we vola- tilize sulphur we get vapour which alters in vapour-density on being heated we might very reasonably expect such to be the fact.Respecting acetic acid there are good reasons for supposing it to be a bibasic acid. It has a great tendency to form double salts with monatomic bases It forms a compound with butyric acid viz. Butyr-acetic acid an acid of considerable stability which as is well known was for some time mistaken for propionic acid. The existence of these double salts and of this double acid is best explained by assigning to acetic acid a double formula viz :-which involves no breach of atomicity i.e. no asmmption that the C H and 0 have other than their usual saturating capacity. Accordingly the vapour-density which acetic acid actually exhibits at low temperatures is in accordance with much of its chemical history.Again the state of condensation of chloride of acetyl and of acetic ether points to the existence of such a compound as-G2H3Q.H43 which we accordingly encounter in the vapours given off by acetic acid when we heat above 200"C. From this it will be seen that the alteration in vapour-density observed when sulphur and acetic acid are heated may with con-siderable probability be ascribed to decomposition. The state of the argument is this a vast number of substances of the most different chemical character and composition have had their vapour-densities taken and have been found to evolve vapours which so far as they have been examined comport them- selves like gases if they be superheated 40"C. That vapours nr HfL PERKIN ON A NBW BROMINE matter what their chemical composition behave like gases appears thus as the result of a first-rate induction. As a set-off to it we should need some example of irregularity in the vapour of a substance which is known to resist decompo- sition. How far the cases of sulphur and acetic acid fall short of this is sufficiently obvious.

ISSN:0368-1769    

DOI:10.1039/JS8651800089

出版商:RSC    

年代:1865

数据来源: RSC

摘要:

PERKIN ON A NBW BROMINE X VITI.-Note on a New Bromine-derivative of Camphor. By W. H. PERKIN. HAVING had occasion to make some experiments on Laurent's bromide of camphor CloHls0.Br2 I found that when strongly heated on the sand-bath it was decomposed with evolution of hydrobromic acid and formation of an oily body which solidified after standing for several hours. As this fact is in direct opposi- \ion to the account of this substance as given by Gerhardt who states that when bromide of camphor is distilled it is decom-posed yielding bromine and camphor I thought it worth while to make a few experiments on the product of this reaction. I there-fore prepared a quantity of this oily product and for the purpose of removing hydrobromic acid washed it with a hot dilute aolu- tiou of potash; it was then separated from the alkaline solution by means of a pipette and transferred to a retort provided with a thermomoter.On heat being applied distillation commenced with evolution of a little hydrobromic acid; the distillate was col- lected until the thermometcr rose to about 60' C. above the boiling point of camphor. The receiver was then changed and the portion which came over above that point collected separately. This on cooling became solid but was kvidently mixed with a small quan- tity of oily matter which was removed by pressure between folds of bibulous paper then dissolved in a small quantity of alcohol and allowed to cool. In the course of a few hours magnificent crystals separated which on being recrystallized were perfectly pure.Alizllysis of a specimen burnt with chromate of lead gave the following numbers :- DERIVATIVE OF CAMPHOR. I. *4050of substance gave ,7723of carbonic acid and -2412 of water. 11. .3557of substance gave -6787 of carbonic acid and *2140of water. 111. *4984 of substance gave ,4050 of bromide of silver. The percentages calculated from these numbers agree closely with those required by the formula C,,H,,BrO as the following comparisons will show :-Experiment. Theory. 1. 11. 111. c, .... 52-00 52.03 H, .... 15 6.493 6.61 6.68 Br .... 0 .." .. 80 16 34632 6.927 34-57 -231 100°OOO The change which bromide of camphor undergoes when heated may therefore be expressed by a. very simple equation :-C,,H,60.Br = C,,H,,BrO + HBr Bromide of camphor.Bromocamphor. Bromo-camphor when pure and slowly crystallized from alcohol appears in transparent prisms very similar to sulphate of sodium but smaller. When impure it sometimes forms tufts of flattened prisms of considerable size. The crystals of bromo-camphor are very brittle and taste more like turpentine than camphor. Bromo-camphor has a slight odour of camphor. It is very soluble in alcohol and ether. It melts at from 76O to 77"C. and if agitated solidifies at 74*C. but some- times if left undisturbed remains liquid until the temperature has fallen as low as 54"C. It boils at 274"C. with slight blackening and evolution of a little hydrobromic acid. lt sublimes slowly even at the ordinary temperatiire.A portion mas heated to 18OoC. in a sealed tiibe with alcoholic ammonia for 12 hours; slight decompositiou took place with for- BLOXAM ON THE ACTJON OF mation of bromide of ammonium and a peculiar organic base ; but the amount produced in this reaction is so small that I have not as yet attempted to investigate its nature. Bromo-camphor when mixed with bromine liquefies apparently without evolution of heat and if the bromine has not been added in too great an excess gradually solidifies into a crystalline mass somewhat similar to that produced by the combination of camphor with bromine. It is most pl'obably a bibromide of bromo-caamphor C,,H,,BrO.Br, a view which has to some extent been corroborated by a quantitative experiment. The product when heated decom-poses with evolution of hydrobromic acid and on coding solidifies into a crystalline mass which probably contains a bibromo-camphor ClOH14BrP*

ISSN:0368-1769    

DOI:10.1039/JS8651800092

出版商:RSC    

年代:1865

数据来源: RSC

摘要:

BLOXAM ON THE ACTJON OF XK-On the Action of Hydrosubhate of Ammonia upon freshly precipituted Subhide of Copper. BY CHARLESL. BLOXAM. THE circumstance that in the ordinary course of qualitative analysis hydrosulphate of ammonia is capable of dissolving sul- phide of copper is well known; but as I could not meet with any explanation of it I have made some experiments which demon- strate the production of a soluble crystalline compound containing copper sulphur ammonia and hydrogen upon the formation of which the solubility of the sulphide appears to depend. When freshly precipitated well-washed sulphide of copper (pre- pared from sulphate of copper and hydrosulphuric acid) was boiled for a minute or two in a flask with colourless freshly prepared hydrosulphate of ammonia (obtained by saturating solution of ammonia with hydrosulphuric acid and adding an equal volume of the same ammonia) an appreciable quantity of the sulphide of copper was taken into solution.To prove that this was not due to any sulphur accidentally mixed with the sulphide of copper the portion left undissolved was rapidly washed and again boiled with the colourless hydro- sulphate of ammonia when a fresh quantity was dissolved. By boiling the sulphide of copper with hydrosulphate of am- HYDROSULPHATE OF AMMONIA ETC. monia saturated with sulphur a very large quantity could be dissolved and the solution when mixed with hydrochloric acid deposited an orange coloured precipitate very dangerously simiiar to that of sulphide of antimony.When the solution of sulphide of copper in t'he strongly sul- phuretted hydrosulphate of ammonia was allowed to stand for some hours in a well-closed bottle it deposited very beautiful vermilion-red tufts of needles resembling chromic acid but of a brighter colour. These crystals were partially decomposed by washing the wash- ings coming away very yellow long after the adhering mother- liquor had been removed and furnishing a dark green precipitate of sulphide of copper when boiled. If the partially washed crystals were rapidly dried over oil of vitriol they assumed a fine copper-red colour and suffered very little decomposition ; but in the moist state they decomposed rapidly evolving an ammoniacal odour and becoming black.They suffered the same change in the water-oven. On heating the crystals (dried over oil of vitriol) in a tube they evolved a trace of moisture and abundance of hydrosulphate of ammonia (judging by the smell) leaving a black residue which evolved much sulphur when further heated. Gently heated with water the bulk of the crystals dissolved leaving a black residue. The yellow solution became dark green and turbid on standing and gave a black precipitate with hydro- chloric acid. Hydrochloric acid did not act upon the crystals in the cold but when heated much hydrosulphuric acid was evolved and a black residue left. No separation of sulphur was perceptible. Nitric acid was also without action upon the crystals until heat was applied when violent oxidation took place and much sulphur was separated.The analysis of the compound was effected by boiling with nitric acid until the sulphur had separated in pure yellow globules which were collected and weighed. The filtrate and washings from the sulphur were precipitated by chloride of barium and the dissolved sulphur calculated from the weight of the sulphate of baryta. The filtrate from this last was precipitated by sulphuric acid and after removing the sulphate of baryta the copper was precipitated by lioiling with potash. The ammonia was determined in a separate portion by boiling BLOXAM ON RYDROSULPHATE OF AMMONIA ETC. with hydrochloric acid till the compound was completely decom- posed removing the small quantity of dissolved copper from the dLition by hydrosulphuric acid tind evaporating the filtered liquid the residue of hydrochlorate of ammonia being carefully dried and weighed.From the evolution of hydrosulphuric acid under the action of hydrochloric acid it was inferred that the ammonia was associated with an equivalent of hydrogen aud it was therefore calculated as NH,. One of the specimens analysed had been rapidly dried over oil of vitriol and the other by repeated pressure between folds of blotting-paper. The results of the analysis were :-Calculated (Cu2NH4S7*) Cu.,.. 32.65 32.11 32-81 S.. . . 58.07 59-07 57-88 NH,. . .. 9.07 8.82t 9.3I 99.79 100~00 1oo*oo -3 The formula which most nearly corresponds with these numbers with a divergence which is scarcely to be avoided in dealing with a compound of this nature would be Cu,NH,S,.Speculating upon the constitution of the compound the two simplest rational formulae which present themselves are 2CuS,. NH,S and 2CuS. NH,S,. The mode of .producing the compound would of course favour the latter formula but I am inclined to prefer the former because (1)there is no sign of the separation of sulphur on treating with hydrochloric acid; (2) of the absence of action on the part of cold nitric acid (conc.) ;and (3) of the action of heat upon the crystals. In works upon qualitative analysis it is often recommended that sulphide of potassium be substituted for hydrosulphate of ammonia as a solvent for the sulphur-acids existing in the hydro- sulphuric acid precipitate when copper is at all likely to be present; but I have often found that copper which might have have been overlooked in the analysis of a large mass of the remaining basic sulphides (e.g. of bismuth and lead) has been easily detected in consequence of its having passed out in the * CU = 31.7 NHI == 18 8 = 16. .t. By difference. BLOXAM ON QUALITATIVE ANALYSIS FOX METALS. 97 hydrosulphate of ammonia solution where it does not interfere with the investigation for arsenic antimony arid tin.

ISSN:0368-1769    

DOI:10.1039/JS8651800094

出版商:RSC    

年代:1865

数据来源: RSC

摘要:

BLOXAM ON QUALITATIVE ANALYSIS FOX METALS. 97 XX-Notes upon the General Routine of Qualitative Analysis for Metals. BY CEARLESL. BLOXAM. Reduction of Binoxide of Tin (Stannic Oxide) by Fusion with Cyanide of Potassium.-When stanaic oxide is fused with cyanide of potassium of commerce the whole of the tin is frequently not obtained in the globule of metal a portion of it being converted into a sulphide by the sulphate of potash present in the cyanide. If the proportion of sulphate of potash be small the rest of the tin is converted into stannous sulphide (SnS) which separates as a black powder on treating the fused mass with water; but if there be much sulphate of potash present a portion of the tin assumes the form of stannic sulphide (SnS,) which is found in the aqueous solution of the fused mass from which it may be preci- pitated by hydrochloric acid.10 grs. SnO rere fused with 50 grs. commercial cyanide of potassium (containing a little sulphate). The liquid mass had a clear yellow colour. The globule of tin weighed 7.1 grs. (calcu-lated 7.8 grs.). On treating the slag with hot water a considerable quantity of black SnS separated. The solution gave a very slight yellow precipitate with hydrochloric acid. 10 grs. SnO were fused with 50 grs. of the same cyanide and 5 grs sulphate of potash. The liquid mass had a brown yellow colour. The globule of tin weighed 6.6 grs. only. The slag when treated with hot water gave no black deposit but the solution furnished an abundant yellow precipitate of SnS when mixed with hydrochloric acid.Since in the final confirmation of the presence of tin it is usual to fuse the supposed binoxide with cyanide of potassium it is im- portant when using the commercial salt to examine not only for metallic tin but for any black sulphide separating during the solu-tion of the fused mass in water and for any yellow sulphide which may exist in thc aqueous solution 98 BLOXAM ON QUALITATIVE ANALYSIS FOR METALS. In the absence of cyanide of potassium the ferrocyanide -answers the purpose for reducing the stannic oxide an alloy of iron with tin being obtained which dissolves in hydrochloric acid and responds to the test with mercuric chloride. Detection of Zinc in Qualitative Analysis.-The absence of well- marked characters in the zinc-precipitates and the dingy appear- ance of the sulphide when obtained in the ordinary course of analysis combine to render the detection of minute quantities of this metal uncomfortable and unsatisfactory.To resolve any doubt the analyst generally resorts to the blow-pipe test with nitrate of cobalt but when this is applied in the ordinary manner upon charcoal to the sulphide of zinc which is usually the last form assumed by the metal at tlie close of the analysis it often fails to give satisfactory results I have found the following mode of operating far more decisive :-The supposed sulphide of zinc is dissolved off the filter in hot nitric acid (dilute) the solution mixed with a very small quantity of nitrate of cobalt (not even enough to impart a pink colour) then with carbonate of soda in slight excess The solution is boiled for a minute or two the precipitate collected on a filter washed and the filter incinerated on platinum foil.The green colour is very bright if an excess of cobalt be avoided and is best seen after the gritty residue has been pow- dered under a glass rod. A .th of zinc can be at once precipitated by yellow hydrosul- phate of ammonia from an,ammoniacal solution. This proportion is not immediately indicated by ferrocyanide of potassium though the solution becomes quite opaque on standing. With dath of zinc the precipitate by fcrrocyanide of potas-sium was formed immediately. Detection of Magnesium.-Every analyst has remarked the fre- quent occurrence of a slight flocculent precipitate by phosphate of soda where the characteristic crystalline precipitate of the am-monio-magnesian phosphate is expected.I have proved that. this precipitate consists of phosphate of alumina which is not men-tioned I think in treatises upon qualitative analysis as being likely to occur in this place. Mineral Constituents of Filter-paper-Having met with some unexpected results in the course of qualitative analyses to test methods of effecting the separation of metals I made a careful analysis of a cousiderable quantity of the ash of ordinary white filter-paper bearing the name of “J. McA. and Co.” (mill num- TILDEN ON PERIODIDES OF ORGANIC BASES. ber 37’). The ash consisted chiefly of silica and alumina but contained considerable quantities of the carbonates of lime and magnesia and of ferric oxide.There were also present small quantities of the aulphates of lime potash and soda and mere traces of phosphoric acid oxide of cobalt and oxide of lead. Inasmuch as a single sheet of paper contaiued appreciable quan- tities of these constituents and such a quantity is often employed in the course of an analysis where it is exposed to the solvent action of acids it appears to be necessary in exact analysis that the composition of the filter-paper should be recorded with respect to the quality as is now generally done with respect to the quan- tity of the mineral constituents.

ISSN:0368-1769    

DOI:10.1039/JS8651800097

出版商:RSC    

年代:1865

数据来源: RSC

摘要:

TILDEN ON PERIODIDES OF ORGANIC BASES. XXI.-On the Periodides of some of the Organic Bases. By w ILLLAM A. TILDEN Demonstrator of Chemistry in the Laboratory of the Pharmaceutical Society. AT different times have been described a number of substances which are formed by the action of iodine upon certain of the organic bases and particularly upon the natural alkaloids in which the greater part of the iodine however enters into no very intimate state crf combination nor does any portion of it occupy the position of a substitute for hydrogen since by simple treatment with nitrate of silver the whole appears to be removed at least in the majority of instances. Moreover a considerable proportion of the iodine is capable of giving the usual reaction with starch and indeed of being expelled with the vapour of water when the solutions of these compounds are boiled.Some of the bodies thus formed are possessed of curious optical properties the most interesting of which is perhaps the iodo-sulphate of quinine accidentally discovered some years ago by Dr. Herapath. Similar compounds have been prepared from codeine papaverine berberine &c.; the only example of a sulphate with which I am acquainted being Herapath’s quinine-salt. A few months ago in the course of some experiments upon caffeine a solution of a few grains in aqueous hpdriodic acid had been placed in a test-tube and forgotten. On examining the I00 TILDEN ON THE PERTODIDEB OF contents of the tube after the lapse of a considerable time it was found to contain a quantity of crystals of peculiar arid beautiful appearance.They consisted of long prisms having a very fine greenish-metallic appearance. After several experiments I found that by dissolving caffeine in weak alcohol acidulated strongly with hydriodic acid and then setting aside the mixture for a few days a inass of crystals was deposited similar to those produced in the first instance their formation being hastened by exposing the solution to light. These crystals were collected but it was found impossible to wash them with water since by such treatment they entirely lose their lustre. A small quantity of very weak spirit containing a drop or two of coloured hydriodic acid may be used with great caution for removing the adhering mother-liquor and they must be dried in vacuo or in a current of dry air since they are in- capable of bearing the temperature of the water-bath.This compound is extremely soluble in rectified spirit forming a brown solution from which by spontaneous evaporation a small quantity cry st allizes apparently unchanged ; the greater part however particularly when evaporated by the aid of heat is deposited in small black nodules being probably the same compound as that mentioned below. The most interesting peculiarity of this substance consists in its action upon light. Examined under the microscope the crystals are found to present all the characters of the polarizing crystals of Herapath. Unfortuiiately the light transmitted is considerably coloured and T have been unsuccessful in preparing plates of sufficient size or tenuity to render them of any service optically.For the determination of the iodine the most convenient plan consists in suspending the powdered substance in water and de- composing by the aid of sulphide of hydrogen or sulphurous acid and subsequent precipitation by nitrate of silver. 1.-*2655 gramme of substance gave ............ -3100 AgI 9) II.-*4895 , , ............ *5702 , 111.-.5755 , I> , ............ *6705 , 1V.-Burnt with chromate of lead and a pretty long coil of cop-per *5840gramme gave .............. H,O *1345 CO -3622. SOME OF THE ORGANIC BASES. I. 11. 111. IV. Mean. Iodine.. 6290 62.94 62-91 - 62.9 1 Carbon.., >J ,f 16.90 16.90 Hydrogen , 3 Y) 2.48 2.48 These crystals mixed with pure iron filings and heated in an oil-bath to 130-140” C. lost a quantity of water equal to 2.5-3 p. c.; a proportion so low as to be sensitive to small changes and since this compound alters in appearance even by long exposure in a vaciium over sulphuric acid it is difficult to obtain it in an absolutely definite state. The results of experiment nevertheless point undoubtedly to the formula :-2 (C,H,,N,O,I,) .3H,O. Experiment. Theory. Carbon . . . 16.90 15.92 Hydrogen . . 2-48 1-82 Iodine . . . . 62.91 63.18 In seeking to prepare this compound with greater facility an attempt was made to obtain it by the addition of alcoholic iodine to a solution of the base in weak sulphuric or hydriodic acid but by that plan I failed to procure anything but a deposition of black granules which appeared to be crystalline.This black suhstance gave in one experiment 74-13 p. c. in another 75.08 p. c. of iodine. It may possibly consist of another com- pound similar to that already described but containing nine atoms of iodine the formula of which would require 74.51 p. c. It appears then that the gradual liberation of iodine in the solution is a condition necessary to the successful production of the polarizing crystals. Bodies of this kind have generally been denominated simply periodides or teriodides and I am not aware of any attempts to ascertain experimeutally the position occupied by the iodine. Dr. Anderson has suggested that a portion may exist in the form of hydriodic acid and ?n assuming two atoms (or four as the case may be) to perform functions different from the other I believe him to be correct.By means of a standard solution of hyposulphite of sodium 1 have made direct determinations o€ tlic amount of cf free,” 102 TILDEN ON THE PERIODIDES OF or as it may be termed rr exterior’’ iodine in the caffeine com- pound. I. 11. Mean. Experiment gave,. . . . . 40422 40.83 40.52 per cent. The formula may then be written thus :-this arrangement indicating that four atoms or 42-12 per cent. of iodine is recognisable by starch &c. In order to test further this view of the constitution of these bodies I thought it would be interesting to prepare if possible the periodide of an ethylated base which should resemble the well-known teriodide of tetrethyl-ammonium.Accordingly a quantity of caffeine was submitted to the action of iodide of ethyl at a temperature of 130”C. for about four hours. At the end of that time the solution contained hydriodic acid and a little free iodine and on gentle evaporation deposited a quantity of brilliant brown scales which were comparatively little soluble in ordinary alcohol. On adding to the mother-liquor of these crystals a solu- tion of iodine best in hydriodic acid a copious precipitation of the same compound is produced ; and by simple recrystallization from alcohol from which solvent it is deposited in glittering scales this periodide is rendered pure and fit for examination.It bears without change or loss of weight the temperature of a water-bath and was submitted to analysis in the manner already described; it is however attacked but slowly by hydrosulphuric or sulphur-ous acid probably on account of its insolubility in water. 1.-.3010 gramme substance gave *3530 AgI Y, 11.-*4650 , ? -5448 > J Y9 III.-.4320 , J) *5028 79 IV.-*2775 , , -3225 , V.-Burut with a mixture of chromate of lead and oxide of copper.3805 gramme gave H,O 00978 CO *2790 VI.-*4860 , , H,O -1193 CO -3590. I. 11. 1x1. IT. V. VI. Mean. Iodine.. . . 63.22 63.31 62-89 62.77 -63.04 Carbon.. . . , ,> , , 19.99 20.14 20 06 Hydrogen.. , 9 >) , 2-83 2-71 2-77 SOME OF THE ORGANIC BASES.The hyposulpbite of sodium solution indicated 42.03 per cent. of free iodine. The mean of the above results corresponds very closely with the numbers required by the formula (C,H,,N402.C2H,I)T2,as may be seen by the comparison exhibited below :- Experiment. Calculated. Carbon . . . . . . 20.06 19.86 Hydrogen . . . . 2.77 2.48 Total Iodine . . 63.04- 63-07 Free Iodine . . 42-03 42.05 By digesting caffeine with alcohol and excess of iodide of ethyl for many days I failed to convert the whole of the base into the ethylated compound and as the iodide of ethylo-caffeine is very soluble I was unable to submit that substance itself to analysis. By treating a quantity of periodide however with sulphuretted hydrogen I was enabled to convert the base into platinum-salt.The chloroplatinate was found to be even more soluble than that of caffeine itself. -3240 gramme gave *0740 metallic platinum corresponding to 22.83 per cent. the formula C,H,,N40,.C,H,.PtCl requiring 23.02per cent. Iodide of methyl appears to furnish a crystalline iodide and periodide of methyl-caffeine with greater facility. The iodide crystallises in large colourless crystals which are very soluble in water less so in alcohol and still less in ether. 09810gramme gave *6825AgI corresponding to 37-59 per cent. of iodine. The formula C8H,,N402.CH,I requiring 37.79 per cent. On dissolving it in water and adding tincture of iodiue an abundant precipitate of periodide is formed which when recrys- tallized from alcohol resembles much the corresponding body containing ethyl.05630gramme gave -6690 AgI corresponding to 6420 per cent. of iodine. The formula (C,H,,N,O,CH,I)I requires 64.37. When caffeine is heated with iodide of ethyl for a few hours only a portion of the base is left unacted upon ; and after preci- pitation of the whole of the cthyl-caffeine by means of iodine it TILDEN ON THE PERIODIDES OF slowly separates in brilliaiit crystals which differ from the first described compound only in containing less water of crystal-lization. 1.-*5965 gramme gave ..................... -7128AgI 11.-Burnt with a mixture of oxide of copper and chromate of lead 04495 gramme- gave H,O *lo85 CO -2678 III.-*4725 gramme gave ......................-5622 , IV..-*2730 , , ...................... -3255 , V.-*4680 , , ..................... a5565 , 11. 111. IV. V. Mean. Iodine ...... 64-57 -64-31 64.43 64.25 64-39 Carbon.. .... , 16-24 )) , >9 16.24 99 >7 Hydrogen. ... 2.68 , >> 2.68 The amount of free iodhe indicated was as follows:-I. 11. Mean. 42.34 43.03 42.68 The mean of the numbers here given corresponds with those demanded by the formula (C,H,,N,02HI)12 + H,O. Experiment. Theory. Carbon. ....... 16.24 16.16 Hydrogen.. .... 2.68 2.18 Total Iodine. ... 64.39 64-14 Free Iodine.. 42.68 48-76 In all the combustions made the carbon numbers are a trifle too high. This may be from the large proportion of iodine and nitrogen present the copper-turnings perhaps being prevented from very perfectly performing their office.Pelletier has described an iodo-strychnine to which he has assigned the formula 4 (C,,H,,N,O,)T,* * I should write this 2(C21H>2N202HI)I. &OME OF THE ORGANIC BASES. and which is prepared by triturating iodine and strycliniiie to- gether and removing the hydrioctate formed by means of boiling water This body is deposited from its alcoliolic solution in orange-coloured scales and contains theoretically 36.13 per cent. of iodine. When a solution of strychnine in dilute alcohol acidn-lated with hydrochloric or hydriodic acid is mixed with alcoholic iodine a browii precipitate is formed which when dissolved in boiling alcohol crystallizes on cooling in very brilliant reddish- brown prismatic crystals.When dried they are extremely brittle and very soon become reduced to a mere crystalline pmder. This compound contains no sdphuric acid and does not lose weight when heated to 140"C. 1.-Burnt with a mixture of oxide of copper and chromate of lead -5550 gramine gave.. ............co *no2 H,O -1720 II.-*7198 gramme gave ....................CO 9198 H,O 9265 111.-Ignited with pure lime -5285 grname gave.. .. 05165AgI 1. 11. JII. Riean. C........ 34.90 34.84 -34-87 H. ...... 3.44 3.49 -3.46 I........ -52-81 52-81 These numbers agree very closely with those required by the formula (C21H22N202HI)12. Experiment Theory. C........ 34.87 35-14 11. ...... 3-46 3-34 I.*...... 52.81 53.13 Pelletier has also described a compound cf hrucine which con- tains 48.9 p. c. iodine. By heating this alkaloid by the same process as the strychnine I obtained a substance which appeared to be identical with that described by Pelletier. Attempts were made to prepare compounds of the same kind from other organic bases aniline among the number but without definite results

ISSN:0368-1769    

DOI:10.1039/JS8651800099

出版商:RSC    

年代:1865

数据来源: RSC