摘要:

ON THE ISOLATION OF THE ORGANIC RADICALS. 263 The following Paper having been received subsequently to the last Meeting of the Society on June 18th was ordered to be published by the Council. XXVI1.-On the Isolation of the Organic Radicals. By E. FRANKLAND. Considering the importance of having positive proof of the existence of the hitherto hypothetical radicals entering on the one hand into the composition of the basic compounds of which alcohol is a type and on the other giving rise to the acids of the series com-mencing with formic acid it is somewhat remarkable that SO few attempts have been made either to isolate these radicals or at least to discover the simpler groups into which they are decomposed at the moment of their separation. Although the method by which Bunsen* succeeded in isolating cacodyl pointed out the conditions under which a similar separation of other radicals might be affected yet with the exception of an unsuccessful attempt made by Lowig to obtain ethyl by the action of potassium upon chloride of ethyl the subject does not seem to have received further attention until Kolbef succeeded in isolating valyl (C H,) by an entirely different method viz.by the electrolysis of valerianic acid. The action of potassium upon cyanide of ethylf induced me to hope that by employing a body of less complex constitution and a metal of a less electro-positive character the radical might be separated without being at the same time broken up into the groups (C HA and (C H3)' The weak affinity possessed by iodine for the organic groiips its * Annalea der Chemie Bd.XLII. s 45. -f Memoirs and proceedings of the Chemical Society vol. III. p. 285. 2 Quarterly Journal of the Chemical Society No. I. p. 60. MR. E. FRANKLAND ON THE energetic action upon metals and the comparatively low temperature at which its organic compounds are decomposed with the separation of free iodine suggested the combinations of this element as being well adapted for such experiments ; and although with the exception of potassium and sodium probably no metal has any action upon these compounds at their ordinary boiling points yet it appeared in the highest degree probable that if the metal and iodide were exposed under pressure to a progressively increasing temperature a point would be attained where the affinity of the metal for iodine overbalancing that of the radical for the same element would determine the decomposition of the iodide.The nature of the products would of course depend greatly upon the temperature and perhaps in some degree upon the nature of the metal employed. From the superior interest possessed by ethyl I selected the iodide of that radical for my first experiments the compound was prepared by placing 7 parts by weight of phosphorus into 35 parts of absolute alcohol and adding in small quantities at a time 23 parts of iodine the vessel being kept cool by immersion in ice-cold water ; the liquid was then decanted from the sediment and distilled in a water-bath the distillate twice washed with water and allowed to stand for % hours over chloride of calcium iodine having been previously added until the fluid remained permanently colourcd ; it was then distilled three times from chloride of calcium mercury and anhydrous oxide of lead :when thus purified its boiling point as indicated by a ther- mometer placed immediately above the liquid was 71.6O C.(161OF.) at 746.5m.m. pressure (29.39English inches) ; with the bulb of the thermometer immersed in the fluid the temperature remained constant at 72.2OC. (162OF.); its specific gravity as indicated by a carefully conducted experiment was 1-9464at 16OC. (61O F.). Burnt with oxide of copper," 0.5618 grms. yielded 0.3190 grms. carbonic acid and 0.1607 grms. water ; numbers which indicate the following per-centage composition Calculated.Expt. 4 eqs. Carbon. . . 300 15-42 15.48 5 , Hydrogen . . 62.5 3.20 3-18 1 eq. Iodine . . . 1585.5 81.38 1948.0 100*00 * In this analysis about four inches of the front end of the combustion tube was filled with copper tuinings and maintained at a heat just below visible redness during the whole operation. After the combustion the liquid in the potash apparatus did not contain a trace of iodine ISOLATION OF THE ORGANIC RADICALS. 265 In order to subject this liquid in contact with different metals to temperatures considerably above its boiling point and at the same time to preserve any gases that might be evolved the following method was adopted tubes of hard Bohemian glass 1 cm.in diameter the thickness of the glass being about 1.3 min. were cut into lengths of 12 inches each and carefully closed at one end before FIG. 1. the blowpipe so as not to diminish the thickness of the glass. The metals either finely granulated or otherwise treated so as to expose a large surface were then introduced and the open extremity of the tube was drawn out to the thickness of a straw ;about an inch of this nar-row tube at b Fig. l. was then brought into the hottest portion of the flame and the glass allowed to shrink up until a fine capillary bore was obtained; the narrow tube was then bent twice at right angles as shewn in the figure. The whole being now warmed the open extremity (a) was immersed in the iodide of ethyl which by the subsequent contraction of the enclosed air was forced into the apparatus in the required quantity; the tube (a) being then connected with an air-pump by means of a strong caoutchouc joint the apparatus was exhausted and the tube finally hermetically sealed at (b) as the liquid boiled violently during the exhaustion it was easy to effect the expulsion of the last traces of air.The tubes thus prepared were afterwards exposed to the necessary heat by immersing them to half their length in an oil-bath. ACTION OF ZINC UPON IODIDE OF ETHYL. A preliminary experiment conducted as above described shewed that the decomposition of iodide of ethyl by zinc commences at a temperature of about 150° C.(302OF.) and proceeds with tolerable MR. E. FRANKLAND ON THE rapidity when an extensive surface of the metal is exposed; white crystals gradually encrust the zinc and glass whilst a colourless mobile liquid remains equal in volume to only about half the iodide of ethyl employed and very different from that liquid in appearance; it was further evident from the cessation of ebullition soon after decomposi- tion commenced that a gas or highly elastic vapour had been gene- rated. Having been maintained at the above temperature for about two hours and the decomposition appearing to be complete the tube was removed from the bath and allowed to cool. On afterwards breaking off its capillary extremity under water about forty times its volume of gas was evolved whilst the whole of the mobile fluid above mentioned disappeared; the gas had a strong ethereal odour burnt with a bright flame and was rapidly and completely absorbed by recently boiled absolute alcohol.On cutting off the upper portion FIG. 2 ISOLATION OF THE ORGANIC RADICALS. of the tube and introducing distilled water the white mass of crystals dissolved with brisk effervescence occasioned by the evolution of a considerable quantity of a gas possessing properties quite similar to those just mentioned. The solution of the crystals thus obtained possesses all the properties of a solution of iodide of zinc and with the exception of a trace of undecomposed iodide of ethyl appeared to contain no organic substance. For the collection and preservation of the gas I used the apparatus shown in Fig.2. A is a bell jar open below and passing easily into the cylinder BB its upper orifice is closed by a sound cork through which passes the glass tube (a) which is bent above at right angles and connected by the caoutchouc joint (b) with the gas-delivering tube (c); within the joint (b) and between the tubes (a) and (c) is placed a piece of glass rod half an inch in length and rather smaller in diameter than the flexible tube so that by means of an external ligature the communication can be opened or closed at pleasure without injury to the caoutchouc connector. It was absolutely necessary to collect the gas over water and to allow it to stand at least twenty-four hours in order that the vapour of un- decomposed iodide of ethyl might be perfectly absorbed during this time a diffusion between the gas and atmospheric air is constantly going on and cannot be wholly prevented even by a layer of oil; since therefore in the present case it was found that the absorption of oxygen by phosphorus could only be effected at a temperature considerably above the fusing point of the latter which would render the correct estimation of the oxygen a matter of considerable difficulty it appeared desirable to prevent the ingress of every trace of oxygen.This object was easily and perfectly attained by mixing some alkaline solution of sulphuret of potassium with the water used in the pneu- matic operations thus the passage of this gas into the receiver was rendered impossible.An earthen vessel of convenient size and admitting of the total immersion of the cylinder BB being filled with this sulphuretted water the bell glass A having the valve (b) open was pressed beneath its surface until the included atmospheric air had been completely expelled through the tubes (a) and (c) which also become filled with the fluid on suction being applied at the orifice (d) ;the valve at (b) being then securely closed the apparatus was ready for the reception of the gas. One of the decomposition tubes before mentioned in which about six grammes of iodide of ethyl had been exposed to the action of zinc was now brought beneath the vessel A and the capillary portion MR. E. FRANKLAND ON THE being cut through with a file the compressed gas rushed into the receiver at first with considerable violence but afterwards in a slow stream which did not entirely cease until after the lapse of nearly a quarter of an hour ; the cylinder BB filled with the prepared water was now brought under the bell jar A and the latter being lowered into it both were removed from the large vessel the gas which I will call a was then allowed to stand over the confining liquid for twenty-four hours before being used for further experiments.After the lapse of twelve hours the contracted portion of the tube from which the compressed gas had been evolved was cut off at c (Fig. l),and a smaller bent tube and cork having been fitted to the orifice distilled water was poured upon the residue and the cork furnished with the gas-delivering tube immediately inserted ; a rapid disengagement of gas ensued which was allowed to escape until every trace of atmospheric air had been expelled; this gas which I will call /3 was then collected in a similar apparatus and with like precautions to those used in the collection of a.The gas a was first submitted to investigation; the determination of its specific gravity was made in a light glass flask capable of con- taining upwards of 200 cubic centimeters and having a millimeter scale etched upon its neck; a few fragments of fused potash having been introduced into this flask and fixed to the glass by being first moistened with water and then gently heated it was carefully filled with mercury and inverted in a vessel containing the same metal.The apparatus BB A being then conveniently arranged the valve (b) was loosened and the gas acting under the external pressure allowed to force out the water occupying the tubes (a)and (c) from the orifice (d),which had been previously immersed in quicksilver ; as soon as the water had been completely expelled and removed from the surface of the metal by blotting paper the bent extremity of the tube (c) was introduced within the neck of the specific gravity flask so that its orifice was somewhat above the level of the external mercury ; by this last arrangement the inconvenience of employing great pressure in BB to overcome that of the mercury was entirely avoided an external column of water a few inches in height being sufficient to counteract the capillary action of the tubes.The gas was allowed to enter the flask until the external and internal mercury stood at the same level and the tube (c) being removed the rest of the gas in A was immediately transferred for eudiometrical analysis to a receiver standing over the mercury a therniometer being now brought into the vicinity of the apparatus the whole was allowed to remain for several hours in a room of constant temperature until the ISOLATION OF THE ORGANIC RADICALS. moist gas became perfectly dried by the pieces of fused potash. The thermometer barometer and height of the internal column of mercury above that in the outer vessel were then read off by means of a telescope placed at the distance of a few feet and the flask after being securely stopped witbout bringing the hand in contact with it was weighed afterwards filled with dry air and lastly with quick- silver the weight being taken in each case.The following numbers were obtained Temperature of room . 6*2OC. Height of barometer . 76009mm. Difference of mercury level . 1904rnm. Weight of flask and gas. . 54.6213 grms. Temperature in balance case . 7.8O C. Weight of flask and air . . 54.4838 grms. Temperature in balance case . 8*0°C. Capacity of flask . 211.23Cbc. From which the sp. gr.was calculated to be 1.5250. The composition of this and of the following gases was determined by the eudiometrical processes of Professor Bunsen by which the estimations can be made with a degree of accuracy previously unattainable in this branch of chemical research I gladly avail myself of this opportunity to express my warmest thanks to that gentleman for the very kind manner in which he placed his laboratory and especially the whole of his admirably arranged eudiometrical apparatus at my disposal during the progress of this investigation.The gas to be examined was transferred into a short eudiometer and rendered perfectly dry by means of a ball of potash the volume being then noted with the necessary precautions a recently ignited coke bullet saturated with very strongly fuming sulphuric acid was introduced and allowed to remain in the gas until the volume of the latter ceased to diminish.After the removal of the coke bullet the sulphurous and vapours of anhydrous sulphuric acid were removed by a ball of moist peroxide of manganese and the gas being lastly dried by a ball of fused potash its volume was again noted. After a specimen of the gas had been removed for combus- tion with oxygen and the remaining volume once more read off absolute alcohol well-boiled and still warm was introduced by means of a bent pipette agitated with the gas and allowed to stand for several hours ;the remaining volume after correction for the tension of alcohol vapoiir was regarded as pure nitrogen. MI%. E. PRAIVKLANI) ON THE The specimen of gas removed after absorbtion by sulphuric acid was transferred into a long eudiometer furnished with platinum wires for the transmission of the electric spark and its volume being taken was exploded with measured quantities of oxygen and atmos- pheric air ;* the volume being again read off a ball of fused potash was introduced and allowed to remain in the gas until every trace of carbonic acid was absorbed; on the subsequent removal of the potash ball and another determination of the volume the remaining gas was exploded with a known quantity of hydrogen in excess and the resulting contraction ascertained.It is almost unnecessary to state that the observations were always made either when the gases were perfectly dry or fully saturated with vapour. The corrections for temperature were calculated according to Marchand’s Tables in which the expansion-coefficient for each degree of the centigrade scale is taken as = 0.003665.Regnault’s table of the expansive force of aqueous vapour was used in correcting for moisture; and for alcohol vapour the numbers given by Schmidt were employed. The volume of combustible gas brought into the large eudiometer was found by deducting from the first reading the due proportion * The analysis of this gas presented some difficulties its combustion in the usual manner with oxygen produced such an intense explosion that no ordinary eudiometer could resist its violence the analysis was therefore conducted in a eudiometer 0.8 meter inlength and the gas previous to combustion was mixed with about 26 times its volume of atmospheric air and 3 times its volume of oxygen by this means the violence of the explosion was moderated and as shewn by Kolbe (Memoirs of the Chemical Society for 1846 p.245) the oxydation of the nitrogen to nitric acid prevented; pure oxygen cannot be used for this purpose since the excess required is too great to be afterwards determined by explosion with hydrogen unless a eudiometer of inconvenient length be employed ;this dilution however cannot be carried beyond a certain limit without interfering with the accuracy of the results for when the explosion becomes exceedingly week a portion of the carbon is oxidized to carbonic oxide instead of carbonic acid as is shewn by the following experiments in which the gas was exploded with different quantities of atmospheric air and oxygen.Vol. of gas. Vol. of air and 0. 0consumed. CO generated. (111.) (1). (11.) 1 1 1 36-3 32.4 28.8 4.40 5.28 5-36 2.82 3.17 3.28 (IV.1 1 18.7 5-54 3.26 In experiments (I.) and (11.) the explosion was very slight and the subsequent com- bustion with hydrogen indicated a larger quantity of nitrogen than was contained in the gas and atmospheric air a result which could only have been produced by an imperfect combustion. In experiment (No.IV.) the heat developed by the explosion was so great that a portion of the mercury was volatilized covering the internal walls of the eudiometer with a black film the greater part of which soon became converted into white crystals of nitrate of mercury. ISOLATION OF THE ORGANIC RADICALS. of nitrogen as ascertained in the small eudiometer.The third and fifth readings vie. the determination of the volume after the admission of oxygen and after absorption of carbonic acid together with the first reading gave data for calculating the amount of oxygen con- sumed independently of the composition of atmospheric air the variations in which would have introduced not unimportant inaccu- racies into the analyses had its average composition been made an element in the calculation. If therefore we denote the volume of combustible gas by (c) the quantity of nitrogen and oxygen con-tained in the mixture at the third reading by (N +0) and the total volume of gas at the third reading by A we obtain the following equation c +(N +0)=A. Further if we represent the volume at the fifth reading viz.the volume after absorption of carbonic acid by B and the unknown volume of oxygen consumed by x; then as B contains all the nitro- gen and oxygen originally contained in (N +0) minus the volume of oxygen which has been consumed by the combustible gas it is evident that (N+0)=B fx. If then we substitute the quantity B+x for (N+O) in the first equation we obtain the expression c+B+x=A. And hence for x the value x=A-B -C. The quantity of carbonic acid generated was obtained by sub-stracting the fifth from the fourth reading and finally the explosion of the remaining gas with hydrogen in excess shewed whether or not perfect combustion had taken place; for if the gas remaining after the absorption of carbonic acid consisted only of oxygen and nitrogen then the quantity of the latter ought nearly to correspond with the amount introduced in the combustible gas and atmospheric air.In none of the following analyses was the heat eliminated by com-bustion with excess of oxygen so great as to cause the volatilization of the quicksilver the occurrence of which when nitrogen is present is always accompanied by the formation of nitric acid. MR. E. FRANKLAND ON THE I. Difference of Corrected VOI. Observed Temp. mercury Barom. at Oo C. and vol. C. level. lmpressure Gas used (dry). 116.2 7*9OC. 14.9mm 738.8mm 81.75 After by so (dry). After removal of 7 specimen for corn-bustion (dry.) After absorption by 1 alcohol. Gas used (dry) After absorption } by SO (dry.After removal of specimen for corn-1 bustion (dry). J After by alcohol 93.6 8-20 30.5 , 735.1 , 64-03 I 82.3 9.0° 42.3 , 735.3 , 55.21 2.7 9.20 42.W 7'32.9 , 1.76 rr. 123.1 8*3O 6.1 , 741.3 , 87.83 98,8 7.7O 24.0 , 739.4 , 68.74 ' 87.8 8.2O 37.3 , 733.1 , 59.31 2.9 8-10 565 , 734.8 , 1-86 111. Gas used (moist). 102.2 8.4O 618.8 , 735-7 , 10.79 After admission of atmospheric air} 543.7 8*6O 160.8 , 735.6 , 298.60 I/ (moist). After admissionof) 569.1 8.7O 137.8 , 735.6 , 325.07 * 0. (moist). After combustion } 537.5 8-7O 166.7 , 735.6 , 291.96 V (moist). * The pressure of the stratum of alcohol resting upon the mercury within the eudiometer in this and the following analyses is calculated into millimeters of quick-silver and added to the difference of mercury level.ISOLATION OF THE ORGANIC RADICALS. IV. Difference of Corrected vol. Observed Temp. mercury Barom'. at Oo C. and vol. C. level. 1" pressure. Gas used (moist). 104.0 8*3O 617.5"" 737*Omm 11.23 After admission of atmospheric air} 538.3 8-3O 166.0 , 736.8 , 293.91 (moist). After admission of 1 577.0 After combustion 1544,3 8*0° 131.6 , 736.1 , 334.38 0. (moist). (moist). 7*9O 160.8 , 736.1 , 300.09 After absorptiol 7.6O 196.4 , 733.5 , 263.99 ,j After combustion 1 532.0 8.3' 79.1 733.1 1 403.98 (moist). 8-3O 171.8 , 732.2 , 285.10 According to analyses I. and II. the original gas contained in 100 parts I. 11. MEAN. Gas absorbable by SO,.. 21-68 21 -73 21.70 Gas unabsorbable by SO . . 75.82 75.82 75.82 Nitrogen . . . . 0 2.50 2-45 2.48- 100~00 100*00 100.00 According to analyses 111.and IV. the combustible gas remaining after absorption by sulphuric acid gave the following results 111. IV. Oxygen consumed by 1 vol. . . 5.48 5-47 Carbonic acid generated by 1 vol. . 3.31 3.32 From the simple laws regulating the atomic volume of gaseous bodies it is evident that no single gas could yield the results just given it was also highly improbable that a gas having the general formula C H could after the action of fuming sulyhuric acid be present since these gases so far as is at present known are all rapidly absorbed by that acid; and as the absence of hydrogen and light carburetted hydrogen had been proved by the solubility of the gas in alcohol the conclusion was almost unavoidable that the mixture consisted of methyl and the hitherto unisolated radical ethyl.It will be seen from the following calculations how far this supposition VOL. 11.-NO. VII. T MR. E. FRANKLAND ON THE was borne out by the combined results of the eudiometrical and specific gravity experiments. The estimation of the relative quantities of ethyl and methyl depends upon the circumstance that ethyl consumes 6$ times its volume of oxygen and generates 4 times its volume of carbonic acid whilst methyl consumes 34 volumes of oxygen and generates 2 volumes of carbonic acid; but as the volume of the mixed gases is known we require only one other known quantity for the formation of two equations from which to determine the two unknown quantities ; the contraction produced by the explosion of the gas with oxygen and which is found by subtracting the fourth from the third reading is a value in which both the oxygen consumed and carbonic acid generated are involved and I have therefore made choice of this number for the second equation.As the quantity representing this contraction is compounded of the volume of Combustible gas plus oxygen consumed minus carbonic acid generated it is clear that ethyl will produce a contraction equal to 39 times its own volume and methyl a contraction equal to 24 times its volume. If then we represent the volume of combustible gas (obtained by subtracting the known amount of nitrogen from the observed volume) by A the contraction produced during combustion by BJand the quantities of ethyl and methyl present respectively by (x)and (y) we obtain the following equations x+ y=A $x + +y = B Hence the values of x and y are x = 2B-5A 2 y = 7A-2B 2 According to analysis (No.HI.) 10.79 vols. containing 0.34vols. nitrogen and 10.45 vols. of combustibie gas consumed 57.25 vols. oxygen and generated 34-59 vols. carbonic acid causing a contraction equal to 33.11 vols. By substituting the numbers here representing the volume of combustible gas and the contraction for A and B in the above equations we obtain the-following numerical values for x and y x = 6.98 y = 3-47 In analysis (IV.) 11.23 vols.containing 0.35 vols. nitrogen and 10.88 vols. of combustible gas consumed 59-51 vols. oxygen and ISOLATION OF THE ORGANIC RADICALS. generated 36-10vols. carbonic acid producing a contraction of 34.29 vols ; from which we obtain as the values of x and y x = 7-09 y = 3.79 Hence the 75.82 per cent. of combustible gas left unabsorbed by fuming sulphuric acid contained on the above supposition 111. IV. MEAN. Ethyl Methyl . . 50.64 25.18- 49.41 26-41- 50.03 25.79 75.82 75-82 75.82 ,In order to ascertain the composition and state of condensation of the gaseous body absorbed by fuming sulphuric acid the original gas ww exploded with atmospheric air and oxygen precautions exactly similar to those already described being observed.The following numbers were obtained v. Difference of Corrected vol. Observed Temp. merciwy Barom'. at 00 C. and vol. C. level. lm pressure. Gas used (moist). 99.6 7.4O 621.5"'" 735.9"" 10.35 After admission of atmospheric air} 508.9 7*2O 192.4 , 735.8 , 265-66 (moist.) After admission of 559.5 7.20 146.0 , 735.8 , 317.37 oxygen (moist). } After(moist). } 530% 7*1° 172.0 , 736.1 , 287.95 Afterabsorptionof } 494.3 7*3O 206.8 , 741.3 , 253.72 CO (dry). After admission of } 701.3 H (dry). 7*3O 24-1, 741.2 , 489.80 After(moist). I 563.3 7.3O 142.8 , 741.5 , 324.29 VI. Gas used (moist). 108.1 92O 610.3 , 7349 , 12.12 After admission of atmospheric air} 533.7 9-2O 167.5 , 734.9 , 288.45 (moist).After admission of 589.9 9.00 117.1 , 734.2 , 347.49 oxygen (moist). 1 T.2 MR. E. FRANKEBND ON THE Difference of Corrected vol. Observed Temp. mercury Barom'. at Oo C. and vol. C. level. I* pressure. After 557.6 8.90 146.6mm 734.3mm 312.76 (moist). I After absorption 518.7 9*Oo 181.2 , 733.1 , 277.13 of CO (dry). 1 After admission of } 706-.3 9,00 18.2 , 732-6 , 488.47 H (dry). After(moist). I 558.0 8.8O 146.4 , 732.4 , 312.18 According to analysis (No. V.) 10.35 vols. containing 10.10 vols. of combustible gas consumed 49.95 vols. oxygen and generated 30.63 vols. carbonic acid; but 10.35 vols. of the original gas would contain according to the mean of the analyses I. and II. 7.85 vols. of combustible gas unabsorbable by fuming sulphuric acid which would consume (vide analyses 111.and IV.) 43.02 vols. of oxygen and generate 26.06 vols. carbonic acid; leaving 6.93 vols. oxygen and 4.57 vols. carbonic acid as the oxygen consumed and carbonic acid generated by 2.25 vols. of the gas removed by fuming sulphuric acid. Analysis (No. VI.) leads to a similar result 12*12vols. containing 11-82 vols. of combustible gas consumed 58.54 vols. oxygen and generated 35.63 vols. carbonic acid; and as this quactity of the original gas would contain 9.19 vols. of the mixture of ethyl and methyl which would consume 50.36 vols. oxygen and generate 3051 vols. carbonic acid therefore the remaining 2.63 vols. of gas absorbed by sulphuric acid consumed 8.29 vols. oxygen and generated 5.00 vols.carbonic acid. Hence the results yielded by the gas absorbable by sulphuric acid may be thus expressed V. VI. MEAN. Oxygen consumed by 1 vol. . . 3.08 3-11 3-09 Carbonic acid generated by 1 vol. 2-03 1-95 1.99 The gas removed by sulphuric acid appears therefore to have exactly the composition and state of condensation possessed by elayl 1 vol. of which requires for its combustion 3 vols. of oxygen and generates 2 vols. of carbonic acid numbers which sufficiently coincide with those just given,when we consider that any errors of observation are concentrated upon a small portion of the combustible gas. To control this result a quantity of the original gas perfectly dried by passing over chloride of calcium was allowed to stream through a ISOLATION OF THE ORGANIC RADICALS.Liebig's potash apparatus containing perchloride of antimony which rapidly combines with the gas absorbable by sulphuric acid but has no action upon ethyl as shewn below or upon methyl. An indefinite quantity of the brown crystallizable liquid thus obtained was carefully burnt with oxide of copper the front end of the combustion-tube being furnished with a layer of copper turnings. After the cornbus- tion the weight of the potash apparatus was found to have increased by 0.1164 grms. and that of the chloride of calcium tube by 0.0473 grms. These numbers correspond with the following atomic pro-portion C H = 0.0053 0.0053 C:H = 2 2 A result which completely confirms the eudiometrical analyses.Whether this body be really identical with elayl or only isomeric with it must be decided by further researches. The per-centage composition of the gas a may therefore according to the mean of the foregoing analyses be expressed as follows Elayl . . 21.70 Ethyl . . . 50-03 Methyl . . 25-79 Nitrogen . 2.48 The theoretical specific gravity of a mixture possessing this com-position agrees closely with that found by experiment as is seen from the following simple calculation C H = 21.70 x 0.96742 = 20.9930 C,H = 25-79 x 1.03652 = 26.7319 C H = 50.03 x 2.00390 = 100*3551 -N -2-48 x 0.96740 = 2.3992 100.00 Specific gravity as found by experiment . 1.5250 EXAMINATION OF THE GAS p. This gas which occupies only about -&of the volume of the last was treated in a similar manner the eudiometrical experiments gave the following numbera MR.E. PRANKLAND ON THE I. Difference of Corrected vol. ObTd Temp. mercury Baromr. at 00 C. and C. level. lmpressure. Gas used (dry). 160.6 13.2O 4*3mm 737.8"" 112.37 After absorption by } 156.2 12.6O 8*7, 741*7, 109.M so (dry)* After removal of} specimen for 128.8 13.9' 37.8 , 742.1 , 86.32 combustion (dry). After absorption by } 8.2 14.00 42.3 , 742.0 , 5 *26 alcohol. These numbers reduced for 100 parts give Gas absorbable by SO . . 2.61 . 91.46 Nitrogen . . . 5-93 100*00 The combustion with oxygen of the gas remaining after treat- ment with fuming sulphuric acid gave the following results 11.Observed Temp. Difference of Corrected vol. vol. mercury Barom'. at Oo C. and C. level. lmpressure. Gas used (moist). 116.9 13.5O 598.9"" 741.8"" 14-64 After admission of 13.4') 240.8 , 741.8 , 211.97 After admission of 1 5m.2 13.P 160.5 , 741.7 , 293.25 0 (moist). After con1bust ion } 502.0 13.4O 195.9 , 741.8 , 255.71 (moist). After absorption -j463.8 1303~236.6 , 738.5 , 221.96 of CO (dry). After admission of } 716.8 13~3~13.7 , 738.4 , 495.32 H (dry). After combustion } 551 ,8 130.5~154.9 , 738.8 , 300.96 (moist). 111 5943 , 738.7 , 15-33 Gae used (moist). 121.2 13~6~ A€ter admission of 1307~ 247.7 , 738-6 , 204.42 ISOLtlTION OF THE ORGANIC RADICALS. Difference of Corrected vole Observed Temp.mercury Barom'. at 00 C. aiid vol. C. level. lm pressure. After admission of) 529.4 1400~ 171*27"" 39.3"" 280.08 0 (moist). After explosion } 488,0 14.3O 209.4 , 739.8 , 240.34 (moist). After absorption } 440.9 13-50 254.7' , 742.0 , 204.72 of CO (dry). admission Of} 662.7 13.90 52.2 , 742.1 , 43594 H (dry) After ] 520-6 14-00 178.0 , 742.2 , 273.49 (moist). According to analysis (No. 11.) 14.64 vols. containing 13.75 vols. combustible gas consumed 57.54 vols. oxygen and generated 33.75 vols. carbonic acid producing a contraction of 37.541 vols. In analysis (No. 111.) 15.33 vols. containing 14.40 vols. com-bustible gas consumed 60.96 vols. oxygen and generated 35.62 vols. carbonic acid suffering a diminution of volume during combustion equal to 39-74 vols.; numbers which correspond with the following proportions Vol. of comb. gas. 0. consumed. CO2 generated. 11. 1 4.18 2.46 111. 1 4-23 2-47 From the behaviour of the gas with fuming sulphuric acid and from the results of its combustion with oxygen there can be no doubt that it is a mixture of the same ingredients as the gas a,the only difference being in the relative proportions of the two; and if we apply the formulze before given we obtain the annexed values for (4 and (Y) ANALYSIS NO. II. x = 3.17 y = 10.58 ANALYSIS NO. III. x = 3.74 y = 10.66 From which omitting the nitrogen we obtain the following per-centage composition MIL E. FRANKLA4ND ON THE I. 11. Elayl 2.78 Ethyl 22.41 25-25 Methyl 74.81 71-97 100~00 The determination of the atomic constitution of the crystalline body from which this gas is evolved would be attended with great difficulty as it is rapidly decomposed on coming in contact with the atmosphere the crystals becoming almost instantaneously brown with the simultaneous production of an oxyiodide of zinc.If instead of allowing the tube to stand for twelve hours as in the above instance water be poured upon the residue immediately after the gas a has ceased to be evolved the resulting gaseous mixture differs widely from that just described in the relative proportions of ethyl and methyl composing it as is shown by the following analysis of gas thus prepared and collected over mercury; the elayl which was present only in small quantity and the vapour of iodide of ethyl were removed by the introduction of a coke bullet saturated with fuming sulphuric acid and the sulphurous acid &c.by the subsequent insertion of a potash ball. The gas was perfectly absorbed by alcohol and therefore contained no trace of nitrogen. Difference of Correctedvol. Observed Temp. mercury Barom'. at 00 C and vol. C. level. 1" pressure. Gas used (moist) 139.0 8-3O 577.5"" 732*tZrnrn 19.76 After admission of atmospheric air\ 487.9 8.3O 213.2 , 731.5 , 241.53 (moist). After admission of} 558.6 8.4O 142.8 , 731.2 , 314.42 0 (moist). After. combustion } 502.9 8.30 199.2 , 731.0 , 255-55 (moist). After absorption of) 435,8 8.2O 260.5 , 733.1 , 199.95 co (dry).These numbers lead to the proportion x y = 9.47 10.29 Or in 100 parts Methyl 52.07 Ethyl . . 47.93 100*00 ISOLATION OF THE ORGANIC RADICALS. 281 It appears therefore evident that the easily condensible ethyl is merely mechanically retained in the interstices of the crystals and gradually evaporates under ordinary atmospheric pressure but as the absolute volume of methyl does not perceptibly diminish under the same circumstances it is highly probable that the latter body enters into the chemical constitution of the crystals. From the foregoing facts the decomposition of iodide of ethyl by zinc may be thus expressed c4 H5 I)= c4zr; Zn A portion of the ethyl thus set free is at the same time decomposed into equal volumes of elayl and methyl C H = C H + C H whilst the iodide of zinc combines with a small proportion of methyl forming a white crystalline compound probably of definite constitu- tion.The analyses of the gas a indicate a slight excess of methyl over elayl which would to a small extent have been increased had the gases a and ,B been collected in the same receiver ; this excess of methyl over elayl is without doubt caused by the presence of a trace of moisture either in the iodide of ethyl or adhering to the zinc since as will be shown below iodide of ethyl and water in contact with zinc are decomposed into oxyiodide of zinc and two volumes of pure methyl. As ethyl must have a considerably higher boiling point than either elayl or methyl it might be expected that on breaking off the extremity of the decomposition tube the two last named bodies would escape first and that the gas produced by the ebullition of the last portion of the condensed fluid would be pure ethyl; to ascertain if this were the case a coupIe of tubes were charged and subjected to heat as before described their capillary extremities were afterwards broken off under quicksilver and the gas allowed to escape until it issued in a slow regular stream the beaks of the tubes were then brought beneath a receiver filled with mercury in which the remainder of the gas was collected.180 C.C. were obtained from the two tubes. Any elayl or vapour of iodide of ethyl that might be present was absorbed by fuming sulphuric acid the vapours of which together with sulphurous acid being afterwards removed by a bullet of fused potash.Two analyses of the gas made with all the before mentioned pre- cautions gave the following numbers MR. E. FRANKLAND ON THE I. Difference of Corrected vol. Observed Temp. mercury Baromr. at 00 C.and vol. c. level. 1" pressure. Gas used (moist) 90.0 12*6O 6260mm ?51*lmm 9.82 After admission of 4759 12-6O 216.4 , 751.2 , 238.32 (moist). After admission of-} 520.7 12.60 174,9 , 751.7 , 281.66 0 (moist). (moist). 484.8 12.50 208-0, 752.0 , 247.17 After absorption Of } 436.1 11.70 255.0 , 753.3 , 208.37 co (dry). After 617.7 12.40 88.2, 753.2 , 392.92 H (dry). Of 1 After (moist). 548.2 1206~ 148-4 , 752.8 , 311*00 11.Difference of Corrected vol. Observed Temp. mercury Bhromr. at Oo C. and vol. c* level. Lm pressure. Gas used (moist). 91.8 12.8" 623*laa 75207~~10.40 471.2 13.0" 219-9 , 752.6 , 234.56 After admission Of 1 535.1 12.9" 160-6, 751.7 , 29635 0 (moist). After } 498% 12.8" 194.0, 751.1 , 260.19 (moist). After absorption Of } 4543 13-0" 237.2 , 741.5 , 218.69 GO (%)* After admission Of } 644.7 13.1" 63.9 , 7408 , 416.41 H (dry). explosion } 532.7 13-00 151.8 , 740*0, 293.39 (moist). These analyses exhibit the following relations between the volumes of combustible gas oxygen consumed and carbonic acid generated Vol. of comb. gas. 0.consumed. C02 generated I. 9.82 63.47 38-80 -1 646 3.95 11. 10-44l 67-26 41-50 -1- .6.47 3.99 ISOLATION OF THE ORGANIC RADICALS. 283 FIG. 3. The gas consists therefore of pure ethyl which theoretically con- sumes 64 times its volume of oxy-gen and generates 4 times its volume of carbonic acid numbers which agree almost exactly with those found in the above analysea. Although the results just given scarcely admit a doubt as to the identity of the gas with the radical ethyl yet in order further to assure myself that the gas was sin-gle and not a mixture I submitted it to diffusion which at the same time served to control the previous specific gravity determination. For this purpose a glass tube (A Fig. 3) 10 inches long 8 inch in diameter and furnished with an etched millimeter scale was used; it was stopped at one extremity (a) by a plug of gypsum (b) 5"" in thick-ness the end of the tube being so ground that whilst it could be closed perfectly gas-tight by the smeared glass plate (c) the latter rested very nearly in contact with the surface of the plaister plug.Before use the instrument was calibrated in the usual manner the stratum of gypsum perfectly dried and the upper end of the tube closed by the glass plate :one leg of a small syphon being now inserted into the open extremity of the tube A the latter was im-mersed with its mouth downwards in the vessel B filled with quicksil- ver until the metal came in contact with the inner surface of the plaister plug; the syphon being removed the tube remained filled with quicksilver whilst the pores 284 MR.E. FRANKLANn ON THE of the gypsum continued open. The gas perfectly freed from moisture was now introduced its volume noted with the proper precautions and after the tube had been so adjusted by means of a vertically sliding holder that the inner and outer quicksilver surfaces stood at the same level the glass plate was removed and the diffusion commenced. During the operation the volume of the gas gradually increased and therefore to preserve it at the exact pressure of the atmosphere it was necessary to keep the inner and outer mercury at the same level by slowly raising the sliding holder. When the diffusion had continued for 10 minutes it was interrupted by replacing the glass plate in its former position and the gas being 6rst dried by a bullet of potash its volume was again read off.The mixture of gas and atmospheric air thus obtained was divided into two portions one of which was introduced into a short eudio- meter for the determination of the relative quantities of air and gas present and the other transferred to a combustion eudiometer in which it was exploded with atmospheric air and oxygen the necessary proportions of the two latter being calculated from the composition of the gaseous mixture as indicated by absorption with alcohol in the short ei diom et er I. Determination of the augmentation in volume during diffusion. Difference of Corrected vol. Observed Temp. mercury vol. c level Barornr.at 00 C. and lm pressure. Gas used (drv). 138.2 142O 13.4mm 741.9"" 95-70 After diffusiln (dry). 158-3 14~1~3.0, 741.9 , 111922 The estimation of the relative quantities of combustible gas and atmsopheric air present in the mixture after diffusion gave the following numbers 11. Difference of Corrected vol. Temp. mercury Barom'. at 00 C. and C. level. lmpressure Gas used (moist). 115.1 14.0° 57*2"" 7454Prn 74.09 After absorption by} 56.4 14*0° 81.1 , 745.8 , 3432 alcohol. The mixture contained therefore in 100 parts Combustible gas . . . . 53.68 rn Atmospheric air . . 46-32 100.0 285 ISOLATION OF THE ORGANIC RADICALS. From these numbers taken in connection with those given in No. 1 the volume of air which had entered and the volume of gas that had escaped during the diffusion are found to be as follows Volume of air entered .. 51.52 Volume of gas escaped . . . 36.00 The combustion of the second portion of the same mixture in the large eudiometer gave the following results 111. Difference of Corrected vol. Observed Temp. mercury Barom=. at 0" C. and vO1* C. level. lmpressure. Gas used (moist). 134.6 14*2O 583.2"" 74L.3"" 18.68 After admission Of I 483.7 14.1O 217.9 , 741.6, 235.35 air (moist). After admission Of l-578-5 14-1O 131.2, 741.6, 329.17 0.(moist). After (moist). 1 54343 1307~ 162.2 , 742.0, 294.16 After absorption Of 1 495.5 13~6~ co (dry)* 207.4, 744*8, 253.64 Analyses No. 11. and No. 111. show that 18.68 vols.of the gaseous mixture contained 10.03vols. of combustible gas which consumed 65.50 vols. oxygen and generated 4052 vols. carbonic acid numbers which express the following proportion Vol. of comb. gas 0. consumed. C02generated. 1 6.53 4~04 The gas has therefore suffered no change in its state of condensa-tion or in the relative proportion of carbon to hydrogen by being submitted to diffusion a result which can only be produced by a single gas or by a mixture of two or more gaseous bodies whose relative proportions are expressed by their diffusion coefficients ; the latter ease must necessarily be of very rare occurrence and in the present instance can scarcely be admitted as possible. This method might in almost every case be employed with advantage to deter-mine whether or not any specimen of gas be simple or mixed.The determination of the specific gravity of ethyl from the above 286 MR. E. FRANKLAND ON THE facts depends upon ,Graham’s well-known law that the rapidity with which gases diffuse is directly as their volumes and inversely as the square roots of their densities; therefore if we denote the volume of air which entered the diffusion apparatus by (a) the volume of gas escaped by (b) and the required specific gravity of the gas by (x) we have the following equation 1 a:b=l:l-.r/x from which the following value for x is obtained a2 x=B If in this equation we substitute for (a)and (6)the numbers deduced from analyses 11.and 111. we obtain 51*522 x = -= 2.0481 362 The specific gravity of the mixture of ethyl methyl elayl and nitrogen was found by weighing to be 1.525 from which the specific gravity of ethyl is calculated to be 2.0462,a number closely corresponding with that just given.By employing a long hffusion eudiometer provided with a mechanical arrangement for regulating the pressure and by using a perfectly dry porous substance in the place of gypsum the specific gravities of gases could no doubt be determined in this manner with very great accuracy. The whole of the above facts taken together prove beyond doubt when iodide of ethyl is decomposed by zinc at an elevated tempera- ture and that the radical ethyl is preeent amongst the gaseous pro- ducts and may easily be separated in a state of perfect purity.Ethyl is a colourless gas possessing a very slight ethereal odour,* burning with a brilliant white flame and having a specific gravity of 2000394. According to the combined results of the specific gravity and eudiometrica1 experiments it contains 2 vols. of carbon vapour and 5 vols. of hydrogen condensed into one volume. I * This odour which is at first very strong probably depends upon the presence of a trace of some foreign body for after purification by standing over water and subse- quent treatment with fuming sulphuric acid it almost entirely disappears ;perfectly pure ethyl is therefore probably like methyl inodorous. ISOLATION OF THE ORGANIC RADICALS. 2 vols. carbon vapour . . = 1.65844 5 vols.hydrogen . . 0.34550 1 vol. ethyl gas . . 2.00394 .~ by weighing. . 2.0462 Found { by diffusion . . 2*04!81 It is incondensible at a temperature of -18O C. (-0°50 F.). Allowed to stream slowly through a serpentine glass tube immersed in a freezing mixture at -18O C. it retained its gaseous condition unaltered but at 3O C. (3705~ F.) and exposed to a pressure of 24 atmospheres in an Oerstedt’s hydrostatic condenser it is converted into a colourless transparent and mobile liquid which instantly reas- sumes the gaseous condition on the pressure being removed; its boiling point at ordinary pressures may therefore be estimated at about -23O C. (905~ F.) 1vol. of absolute alcohol at 142O C. (58O F.) and 744-8””pressure absorbs about 18-13vols.of ethyl agitated with a small quantity of alcohol over mercury the gas rapidly disappeared with the exception of a small bubble which did not amount to per cent on afterwards throwing up a few drops of water the alcohol assumed a milky appearance followed by a rapid disengagement of gas which in a few seconds amounted to very nearly the original volume. Ethyl is not acted upon by fuming sulphuric acid; it is scarcely affected by concentrated nitric acid and chromic acids and does not combine with iodine or sulphur even on the application of heat; in the case of the latter element sulphuretted hydrogen is copiously evolved and carbon separated as the temperature approaches redness. Mixed with half its volume of oxygen and conducted over spongy platinum it remains unchanged at ordinary temperatures but on a gentle heat being applied the sponge becomes incandescent water is formed with the simultaneous separation of a small quantity of charcoal and a gas probably light carburetted hydrogen insoluble in alcohol burning with a feebly illuminating flame and generating much carbonic acid is the remaining product of the decomposition.Like methyl ethyl is not absorbed by perchloride of antimony even under the influence of bright sunlight; chlorine has no action upon it in the dark but when equal volumes of the two gases are exposed to diffused daylight combination rapidly takes place accompanied by a contraction of volume and the production of a colourless liquid. Bromine also acts upon ethyl when exposed to bnght sunlight with the application of a gentle heat.I have not yet completed the MR. E. FRANKLAND ON THE examination of the products of this and the former reaction and must consequently defer the communication of further details to a future opportunity. In the hope of avoiding the formation of methyl and elayl during the preparation of ethyl I was led to try what influence the presence of water alcohol and ether would have upon the decomposition of iodide of ethyl by zinc and although the expectation of preventing the secondary decomposition of the ethyl was not realized yet the results of the experiments are in other respects not wholly uninteresting. ACTION OF ZINC UPON IODIDE OF ETHYL IN PRESENCE OF WATER.Equal volumes of water and iodide of ethyl were introduced together with zinc into a decomposition tube which was then exhausted hermetically sealed and exposed to heat as before described ; decom-position commenced and proceeded at a lower temperature than that required for inducing the action of zinc upon iodide of ethyl alone ; the fluid contents of the tube became thick and oleagenous and during the subsequent cooling solidified to a white soft amorphous mass. On afterwards opening the tube under sul-phuretted water a large quantity of gas rushed out with great violence and was collected in the apparatus with the precautions already described. No gas was eved on subsequently treating the residue with water. The eudiometrical examination of the gas gave the following results I.Difference of Corrected vol. Observed Temp. mercury Barom'. at 0" C. and vol. C. level. lm pressure. Gas used (dry). 55.9 7*4* 74.9"" 741-3"" 36.27 After action Of} 55.9 7*7O 73.3 , 739.8 , 36.24 fuming SO (dry). The gas remaining after the action of fuming sulphuric acid was so nearly absorbed by alcohol that the extremely small residue could not be estimated. ISOL4TION OF THE ORGANIC RADICALS. 11. Difference of Corr. vol. at Observed -Temp. mercury Baromr. Oo C. and 1'" T. 01. C. vol. pressure. Gas used (moist). 100-5 8*0° 621.3"" 739 6"" 10-77 After admission of atmospheric air} 514.1 8-0° 187.9 , 73900 , 271.25 (moist) After admission of 8.0° 162.7 , 738.5 , 298.21 0.(moist). ) 540.6 After(moist). ' explosion) 513-9 7.8O 188.3 , 738.0 , 270-69 After absorption } 488.0 of CO (dry). 7*6O 212.0mm 738*lrnm249078 After admission of } H (dry). 717.9 7.7O 10.2 , 737.9 , 508.08 After 'eiplosion 1 612.0 8.0° 100*1 , 737.8 , 374.40 (moist). 111. Gas used (moist). 155.0 8*2O 558.6 , 737% , 25.75 After admission of atmospheric air 521.2 8*0° 182-1 , 73743 , 277.08 (moist). 1 After admission of 0. (moist). } 573.0 8*0° 135.1 , 737.7 , 331.00 After explosion1 509.1 7-8O 193-1 , 738.0 , 265.79 (moist). J After absorptionof 1 449.6 7.90 246.2 , 738% , 215.24 co (dry)* After admission of 1 665.1 H (drv). \ .I/ After explosion1 629.2 &lo 52.0 , 737.9 , 443.04 (moist). 8.5O 82.7 , 736.9 , 394.12 These analyses show that the gas does not contain a trace of elayl and further that it requires for its combustion 39 vols.of oxygen generating 2 vols. of carbonic acid Vol. of comb. gas. 0. consumed. CO generated. Analysis TI. 10.77 37.66 20.91 - *1 3-5b 1*94 Analysis 111 25 75 90.01 50.55 - *1 3.50 1.97 VOL. 11.-NO. VII. U 290 MR. E. FRANKLAND ON THE These are however precisely the results obtained in the analysis of methyl* with which this gas exactly coincides in all its properties. It is colourless nearly insoluble in water but soluble in alcohol 1 VOI. of which at 8.8O C. (48O F.) and 665.5"" pressure absorbs 1.22 volumes; it possesses at first a slight ethereal odour which by heating the gas first with alcohol and afterwards with concentrated sulphuric acid entirely disappears leaving the methyl perfectly in- odorous.It is incondensible at a temperature of -18O C. (-0.5' F.); mixed with chlorine it remains unacted upon in the dark but in diffused daylight the colour of the chlorine rapidly disappears proving that combination has taken place; it does not combine with iodine or sulphur even when these substances are heated in the gas. There can therefore be no doubt that the gaseous product of the decomposition of iodide of ethyl and water by zinc is pure methyl and that it is identical with the gas evolved by t.he action of potassium upon cyanide of ethyl,? and by the electrolysis of acetic acid.$ An attempt to condense methyl by the application of pressure was unsuccessful; at 30 C.(37.5O F.) and under a pressure of 20 atmo-spheres (the highest which the apparatus at my disposal would bear) it exhibited no signs of liquefaction. The white residue remaining in the decomposition tube after the escape of the gas exhaled a strong odour of ether but contained no other organic substance the white amorphous mass consisted of oxyiodide of zinc. The formation of methyl by the action of zinc upon water and iodide of ethyl is explained by the following equation C H I + HO + 2 Zn = 2 (C H3) + Zn 0 Zn I. The generation of methyl during this decomposition might also be explained by assuming that the radical ethyl is split up into the groups (C H,) and (C H3) and that the former is retained in the residue whilst the latter escapes as gas to convince myself that this was not the case I submitted a weighed quantity (2.268grms.) of iodide of ethyl to the action of water and zinc in the manner already described ; after the decomposition was ended and the tube perfectly cooled the latter was opened the gas allowed to escape and the residue quickly mixed with cold oxide of copper and burnt in a * Quarterly Journal of the Chemical Society for April 1848 p.65. j-Journal of the Chemical Society for April 1848 p. 60. $ Annalen der Chemie. Bd. LXIX.s. 279. ISOLATTON OF THE ORGANIC RADICALS. combustion tube as in an ordinary organic analysis. The weight of the potash apparatus increased by 0.132 grnis. equivalent to 0.036 grms.carbon this is however only + of the quantity of carbon required if the products of the decomposition are elayl methyl and iodide of zinc for on this supposition the residue from 2.268grms. iodide of ethyl containing the corresponding quantity of elayl ought to yield 0.641 grms. carbonic acid (= 0.175 grms. C.) instead of 0.132grrns. as found in the above experiment. The occurrence of a large quantity of oxyiodide of zinc in the residue is also in itself a sufficient proof that the ethyl on its separation from iodine is converted by the assumption of an atom of hydrogen into 2 vols. of methyl gas. This conclusion is also further confirmed by the fact that iodide of ethyl and water heated in an hermetically sealed tube to the tempera- ture employed in the above production of methyl are transformed into ether and a concentrated solution of hydriodic acid.This formation of ether also explains the occurrence of that body in the white residue and the production of carbonic acid on its subsequent combustion with oxide of copper. The transformation of iodide of ethyl in contact with water and zinc into oxyiodide of zinc and 2 volumes of methyl furnishes a convenient method for preparing that radical in large quantities perfectly pure ; upwards of 300 cubic centimetres being obtained from a single decomposition tube of the dimensions previously stated. It is necessary that the operator should take precautions to preserve himself from the danger attending the possible explosion of the tubes during the decomposition ; the apparatus ought therefore always to be enclosed in a strong wooden case open behind and having a double plate-glass window in front through which the progress of the operation may be watched.The quantity of iodide of ethyl intro- duced into each tube of the above dimensions ought not to exceed 3.5 grms. and the temperature of the oil-bath should not be allowed to rise above 180° C. (356O F.) During the whole of the foregoing experiments no instance of explosion occurred although the pressure within the tubes must in many instances have amounted to between 80 and 100 atmospheres. ACTION OF ZINC UPON IODIDE OF ETHYL AND ALCOHOL. This experiment was conducted in precisely the same manner as the last absolute alcohol being substituted in the place of water.ua MR. E. FRZSKLAYD ON THE The appearances presented during decomposition and the quantity of gas evolved on subsequently opening the tube were almost exactly identical with those observed in the decomposition of iodide of ethyl in the presence of water. The residue in which the odour of ether was easily recognized did not evolve a further quantity of gas on the addition of water. The eudiometrical analysis led to the following results Observed I. Diff. of Temp. mercury C. level. 8*8O 6*lmm 8*2* 8.2 , 9*Oo 43.8 , 8*6O 81.9 , 11. Diff. of Temp. mercury C. level. 8-0° 576.9 , 8*3O 192.6 , 8.4O 128.7 , 8.2O 172.3 , 7.9' 213.2 , 8*0° 23.7 , 8*1° 140-9, Con.vol. at Barometer. Oo C. and 1 pressure. 732*3mm 86.32 740.0 , 85.89 732.6 , 56.21 V 732.1 , 2.06 Corr. vol. at Barometer. 0" C. and 1" pressure. 741.0 , 20.73 741.3 , 264.37 741.1 , 336.81 740.9 , 286.39 738.2 , 24q6.08 737.7 , 486.95 7'37.3, 323.44 Gas used (dry). After action Of} fuming SO (dry). After removal of specimeiforcom-bustion (dry). After absorption } by alcohol. Gasused (moist). After admissionof 1 atmospheric air vol. 122.7 120.9 84.3 3.1 Observed vol. 136.7 (moist). After admission } 574.6 of 0 (moist). After explosion } 526.3 (moist). After absorption 1 482.3 of CO (dry). After admission } 702.0 of H (dry). After explosion 1 566.1 (moist).Analysis No. I proves the absence of elayl and the presence of 3.66 per cent nitrogen. Analysis No. 11 gives the following ISOLATION OF THE ORGSNIC RADICALS. proportion of combustible gas to oxygen consumed and carbonic acid generated Vol. of comb. gas. 0 consumed. CO generated. 19-97 70.76 40.31 -1 3'54 2*02 The gas has therefore the same composition and state of con-densation as that evolved by the action of zinc upon iodide of ethyl and water with which it also exactly coincides in physical properties. The presence of oxyiodide of zinc and ether in the residue leave no room for doubt that 1 eq. iodide of ethyl with 1 eq. alcohol and 2 eqs. zinc give rise to 2 eqs. methyl 1 eq. ether and 1 eq. oxyiodide of zinc 2 (C H7) C H 0.HO C,H,O 2Zn ZnO.ZnI. ACTION OF ZINC UPON IODIDE OF ETHYL AND ETHER. Equal volumes of iodide of ethyl and ether were heated with zinc in a sealed tube to a temperature of about 150° C. (302OF.) until the action appeared complete on being allowed to cool the residual thick oily fluid did not solidify. When the beak of the tube was afterwards broken off only a few cubic inches of gas were evolved but on pouring water upon the residue a strong effervescence produced by the disengagement of a much larger volume of gas occurred. The two specimens of gas were collected in the same receiver and on being submitted to analysis yielded the following results I. Diff. of Corr. vol.at Observed Temp. mercury Barometer.OoC. and lm vol. C. level. pressure. Gas used (dry). 185.2 After absorition -,75.1 After removal of 1by so (dry). I specimen for corn-105.7 } 7.4After absorption bustion (dry). 1 by alcohol. 1209~ 19.7"" 4.3 , 13.00 I 14.3' 65.8, 14.1O 71.2, 744.2"" 741.4, 745*9, 746.4, 128.18 123.20 68.31 4-58 MR. E. FltAKKLdND ON THE 294 11. Difference of Corr. vol. at Observed Temp. mercury Barornr. 00 C. and 1'" vol. C. level. pressure. Gas used (moist). 48.3 13*0° 361.7"" 74O*Omm 16.92 13*1° 92.2 , 739-8, 189.83 (moist). After admission of 1 355.5 12.7O 48.4 , 738.8, 230.82 0 (moist). After. combustion 1 309.9 l2*7* 98.1 , 739.4 , 186.67 (moist). After absorption of 260.5 l2.9O 144.6, 738.3, 147.68 co (dry). After admission of ! H* (dry) 388.1 13.0° 14.8, 737.9 , 267.87 After admissionof 427.2 13-3O 12.8, 737.3 , 295.12 0 (dry).1 After combustion 302-0 13~4~102.4, 737.1 , 179.40 (moist). I-According to analysis No. I the per-centage compositiou of the gas may be thus expressed Gas absorbable by SO . 3.84 Gas unabsorbable by so . . 89.71 Nitrogen . . 6.45 100~00 Analysis No. 11 exhibits the following relation between the volumes of combustible gas oxygen consumed and carbonic acid generated Vol. of comb. gas. 0 consumed. CO generated. 15.83 67.31 38.99 -1 4.25 2-46 These numbers indicate that the combustible gas not absorbed by fuming sulphuric acid is a mixture one of the constituents of which must have a higher atomic weight than methyl. Prom the small residue left after the action of alcohol which precludes the presence of hydrogen and light carburetted hydrogen from the occurrence of elayl and the behaviour of iodide of ethyl in contact with zinc alone and in presence of water and alcohol we may ISOLATION OF THE ORGANIC RADICALS.safely conclude that the gas in question is a mixture of ethyl and methyl and on applying the formula previously given we find that the 15-83vols. of combustible gas insoluble in fuming sulphuric acid consist of 4.57 vols. ethyl and 11-26vols. methyl therefore omitting nitrogen the per-centage composition of the original gas may be thus stated Elayl Ethyl . . . . . 4.10 27-68 nlethyl. . . . 68.22 100~00 Although these experiments cannot by any means be considered as a complete investigation of the action of zinc upon iodide of ethyl in presence of ether yet they afford sufficient evidence that the separation of the elements of water from the ether has been effected producing a transformation of ethyl into 2 vols.of methyl; the elements of water have not however been so readily eliminated as altogether to prevent the formation of ethyl. The olefiant gas owes its origin no doubt to the secondary decomposition of a portion of the ethyl into (C H,) and (C HJ whilst the group (C H4) remaining after the separation of the elements of water from ether would probably be found in a dark-coloured oily liquid which collected in small quantity on the surface of the water poured upon the residue in the decomposition tube; the composition of this dark- coloured liquid and the state in which the gases are retained by the oleagenous residue have not yet been determined.In conclusion I will describe very briefly the behaviour of iodide of ethyl in contact with several other metals at elevated tempera- tures after exposure for 12 hours to a heat varying from 150°to 200°C. (302O-392O F.) iron lead copper and mercury scarcely affected the decomposition of a trace of iodide of ethyl ;but heated with arsenic to about 160°C. (320O F.) the iodide was rapidly decomposed a heavy blood-red liquid probably As I, being formed which solidifies into brilliant crystals on cooling. The opening of the tube proved that the internal vacuum was unimpaired and the crystalline mass evolved no gas on being treated with water in which it was very slightly soluble ; the remaining fragments of arsenic possessed a remarkably brilliant metallic lustre which gave them the appearance of anti- mony.Tin also effected the decomposition of iodide of ethyl at about the same temperature ; the iodide became gradually replaced 295 MR. FRQNKL1ND ON THE ORGANIC RADTC ILS. by a yellowish oily fluid which solidified to a crystalline mass on cooling no gas was evolved either on opening the tube or subse-quently treating the residue with water. It would be interesting to ascertain into what combination the raciical ethyl enters in the two last decompositions. Finally iodide of ethyl is rapidly decomposed by potassium at about 130' C.(266OF.); methyl gas and a yellowish ethereal fluid which has not been investigated are the products of the decomposition. Although the foregoing investigation furnishes the materials yet I refrain from giving any general views on the probable constitutioii of the radicals of the series to which ethyl and methyl belong until I have extended the inquiry to some other members of the same series as well as :to the compounds of the electro-negative class of radicals of which formyl acetyl &c. are members.

ISSN:1743-6893    

DOI:10.1039/QJ8500200263

出版商:RSC    

年代:1850

数据来源: RSC