FRANKLAND AND DUPPA’S TI.-Synthetical Researches on Ethers. No. 2. Action of Sodium and Isopropylic Iodide upon Ethy lic Acetate. By E. FRANKLAND, F.R.S. and B. F. DUPPA,Esq. IN a former memob* we described the consecutive action of sodium and the methylic ethylic and arnylic iodides upon ethylic acetate. Two distinct classes of bodies resulted from these reactions viz. lst bodies derived from the duplication of the molecule of ethylic acetate ; and 2nd bodies resulting from the substitution of one or more atoms of hydrogen in the methyl of acetic acid. The general formula of the first of these classes of compounds may be thus written :-{ ::;;; In this formula R may be either hydrogen or a monad organic radical. These bodies to which we gave the name carboketonic * Phil.Trans. vol. clvi p. 37 and Chem. SOC. J. vol. xix p. 396. SYNTKETICAL RESEARCHES ON ETHEES. etl2ers are derived from corresponding compounds in which sodium occupies the place either of one or of both atoms of R the latter compounds being themselves obtained by the action of sodium upon ethylic acetate according to the following equations :- 4{:$hto + Na = 2 + H, Ethylic acetate. Ethylic sodacetone carbonate. Alcohol. 2{z&to + ~a,= COiSle + H,. COEto Ethyiic acetate. Ethylic disodacetone Alcohol. carbonate. The second class of bodies have the general formulae :-COEto' They are obtained by the action of the iodides of the poslitive compound radicals represented by R upon corresponding sodium compounds viz.:-{:;E; {%E CCNa, COEto' Ethylic sodacetate. Ethylic disodacetate. Ethylic trisodacetate. These sodium compounds are produced simultaneously with those belonging to the first class by the action of sodium upon ethylic acetate. Thus ethylic disodacetate arises from t,he following reaction :-Ethylic acetate. Eth3ic disodacetate. By contact with the iodide of any radical C,R,,+, these cornpounds exchange their sodium for an equivalent amount of C*'H,,+ 1 ttllus:-Ethyiic disodtlcetate. EthFlie salt. 104 FRANKLAND AND DUPPA'S If in these formule n = 0 ethylic acetate ({-coj&o) isre-CH produced but if n be a positive integer an ethereal salt is obtained of the molecular weight of ethylic acetate increased by one two or three times C,H,,.We have now extended these reactions to isopropylic iodide for an ample sqply of which we are indebted to Professor Wankl y n. The sodium compounds derived from ethylic acetate and prepared as described in our former communica- tion,* were treated with excess of isopropylic iodide aiid digested for 24 hours in a water-bath an upright Liebig's condenser being attached to the flask containing the materials. At the end of this time the products volatile at 100" were dis- tilled off. They consisted chiefly of ethylic acetate isopropylic iodide and isopropylic ethylic ether ({Y::). Water acidu- lated with sulphuric was now added until the contents of tlu? flask exhibited a decidedly acid reaction. They were then submitted to distillation.A sweet-smelling oily liquid passed over along with water; it mas separated dried over calcic chloride and distilled. It began to boil at about 70" C. and the thermometer rose eventually to 300' 0. Below 100" the dis- tillate which consisted chiefly of ethylic acetate isopropylic iodide and alcohol contained an abundance of two products one boiling at about 135"C. and the other at about 200°C. The latter gave with baric hydrate the characteristic reaction of a carboketonic ether whilst the former possesned in a high degree the peculiar odour of ethylic valerate. ETEYLIC &3OPROPACETONE CA4RBONATE. The section of the above distillate boiling at about 200° yielded on careful rectification a liquid boiling constantly at 201' C.Submitbed to analysis this liquid gave the following results :-I. -3402 grm. gave -7826 grm. carbonic anhydride and -2896 grin. witter. 11. -1861 grm gave a4274 grm.ca'rbonic anhydride and el594 grm. water. * Chem. SOC. J. vol. xix p. 396. SYNTHETICAL RESEARCHES ON ETHERS. These numbers lead to the formula as seen in the annexed comparison of caIculated and experi- mental numbers :-Calculated. Found. -/ A I. 11. Mean. C9. .. 108 62-79 62-73 62.63 62.68 . 16 9.30 9.45 9.51 9.48 0,.... 48 27-91 .. .. 27.84 100*00 This product of the action of sodium and isopropylic iodide upon ethylic acetate is therefore homologous with ethylic methacetone carbonate and ethylic ethacetone carbonate ob-tained in the corresponding reactions with ethylic and methylic iodides as is evident on inspection of their respective for-mulae :-COMe COhSe COMe CMeH ; CEIH; CPPrH*.COEto COEto COEto Ethylic methacetone Ethjlic e thacetone Ethylic isopropacetone c irbonnte. carLonate. carbonate. Ethylic isopropacetone carbonate results from the action of isopropylic iodide upon ethylic sodacetone carbonate according to the following equation :- COXe COMe CNnH + PPrI = {CdPrH + NaI. COEto COEto Echylic soda- Isopropylic Ethylic isoprop-acetone iodide. acetone carbonate. carbonate. Ethylic isopropacetone carbonate is a colourlesa and somewhat oily liquid of an odour resembling damp &raw and a pungent. taste. It is insoluble in water but miscible in all proportions with alcohol and ether.Its specific gravity at 0" C. is -98046. It boils at 201" (barometer -7584 metre) and distils without decom- position. A determination of its vapour-density by Gay LIISS~C'S niet>hod gave the following results :-VOL. xs. FRANELAND AN3 DUPPA'S Weight of ethylic isopropacetone carbonate .. -1248gna Observed volume of vapour .. .. . . 34.9 c. c. Tempemture of bath .. .. .. .. 225'C. Height of barometer .. .. .. .. 767 m.ni. Difference of heights of mercury inside and out-side of tube ,. .. .. .. *-136 9? ?? Height of spermaceti column reduced to milli-metres of mercury . . .. .. .. 16-6 , , From these data the weight of one litre of ethylic isoprop acetone carbonate is calculated to be 85-6 criths or its Bpecific gravity compared with air taken as unity is 5.92.Theoretically the vapour of a body of this composition and occupying 2 vols. ought to give the numbers 86 criths and 5.94. Ethylic isoprop- acetone carbonate has no action upon polarized light. Boiling aqueous solutions of potash and soda rapidly decompose ethylic isopropacetone carbonate which also suffers a similar decompo- sition when boiled with baryts-water. Baric carbonate is in the latter case precipitated and a volatile liquid possessing a campboric odour produced. This liquid washed with salt and water and dried over quicklime boiled constantly at 114OC. and yielded on analysis the following numbers :-I. *2032 grm. gave *5338 grm. carbonic anhydride and -2250 em.water. 11. ,1722 grm. gave -4550 grm. carbonic anhydride and -1890 grm. water. The following comparison shows that these numbers agree closely with the formula :-Found. Calculated. I. 11. Mean. b. c6.4 -. 72 71-64 72-06 '71.85 H, .... 12 12-30 12-19 12-24 O...... 16 .. .. 15.91 I-100 100~00 Thia result is exactly homologous with those obtained in the corresponding reactions which we have previously described. For reasons given in the memoir above cited we regird SSXTKETICAL RESl&~CHESON ETHERS. this body as acetone in which one atom of hydrogen haB been displaced by isopropyl {%be# {%2 Acetone. Isopropacetone. and we propose for it the name isopropacetone. Isopropacetone is produced by the action of baryta-water upon ethylic isopropacetone carbonate according to the follow- ing equation :-CBPrH + BaHo = COBao" + EtHo + (COMe CBPrH,.COEto Baric Baric Alcohol. Ethylic isopropacetone hydrate. arbpnate. Isopropacetone. -rMe carbonate. Isopropacetone is a colourless transparent and very rnobiie liquid possessing a powerful camphoric odour and a burning taste. It is very sparingly soluble in water but miscible in all proportions with alcohol and ether. Its specific gravity is -81892at 0" C. It boils at 114' C. with the barometer at T584 meter. A determination of its vapour-density gave the follom-hgnumbers :-Weight of isopropacetone ............ *1160p. Observed vol. of vapour .............. 43.9 c. c. Temperature of bath ................137" C. Height of barometer ................ 764 m.m. Difference of heights of mercury inside and outside of tube ................ 112 mm. Height of spemaceti column reduced to millimetres of mercury. ............. 16.8 m.m. Hence one litre of the vapour weigha 50.1 criths and its ~p. gr. is 3.48. A two-volume vapour of the above formula requirw the numbers 50 criths and 3.455 Isopropacetone doea not reduce boiling aolution of argentic nitrate. Agitated with a concentrated solution of hydric sodic aulphite it solidifies to a Bplendid mass of white crystals. A ketone of the same composition (methyl valeral) has been obtained by Williamson in distilling a mixture of potassic acetate and valerate. This body which for reasons mentioned below we regard a8 isomeric with isopropacetone boils at FELA\NKLhXD AND DUTPA'S 120' C.Isopropacetone is also isomeric with ethyl-but,yral boiling at about 128' C. Amongst the products of the action of sodium and isopro- pylic iodide upon ethylic acetate there ought to be a carbo-ketonic ether containing two atoms of isopropyl and having a constitution analogous to that of ethylic diethacetone car bonate. COMe {:::r0 cm, {%to Ethylic diethaaetone Ethylic di-isopropacetone carbonate. carbonate. Unmistakeable indications of the existence of this body were noticed hut we have not attempted to isolate it. Isopropacetic Acid. The section of ebhereal product described above a8 boiling at about 135' C. yielded on further distillation a considerable quantity of a liquid boiling constantly at 134' to 135' C.Thk liquid was submitted to analysis and gave the following numbers :-I. m1836 grm. gave -4361 grm. carbonic anhydride and -1832 grm. water. 11 *2786 grm. gave -6602 gm. carbonic anhydride and -2722 grm. water. These results lead to the formula as will be evident from the following comparison of analytical and calculated numbers :- Calculated. I. Ir. Mean. C .... 84 64.62 64.78 64.63 64-70 H, .... 14 10.77 11-08 10.86 10.97 0 .... 32 24.61 .. 24-33 130 100*00 100~00 The formula and reactions of this body prove itfto be ethylic isopropcacetate; that is ethylic acetate in which one 1 atom of aon-ethylic hydrogen has been displaced by isopropyl - SYNTHETICAL RESEARCHES ON ETHERS.Ethylic isopropacetate is produced from ethylic sodacetate by the following reaction :-Etbylic Isopropylic Etbylic isoprop sodmetate. iodide. acetate. Ethylic isopropacet,ate is a colourless transparent and oily liquid nearly insoluble in water soluble in alcohol and ether and undistinguishable in odour from ethylic valerate (ethylic propacetate) with which as we have proved below ethylic isopropacetate is isomeric. Its specific gravity is 8882 at 0' C. and -87166 at 18' C. It boils at 134' to 135' C. (barom. 7584 metre). A determination of its vapourdensity gave the following number8 :-Weight of ethylic isopropacetate ...... -1396 grm. Observed volume of vapour .......... 41.56 cbcx. Temperature of bath ................147' C. Height of barometer ................ 751.4 m.m. Difference of heights of mercury inside and outside of tube.. .............. 110.5 m.m. Height of spermaceti column reduced to millimetres of mercury .......... 17.9 m.m. Hence the sp. gr. of the vapour is 4-64 or one litre weighs 67.1 criths. A two-volume vapour of the above formula re- quires the numbers 4.49 and 65 criths. Ethylic isopropacetate is readily decomposed by alcoholic potash potassic isopropacetate being formed. The alcoholic liquid so produced being mixed with water and evaporated to dryness left a saline residue which was treated with dilute sul- phuric acid and submitted to distillation. An oily liquid passed over which strongly reddened litmus paper.This liquid sepa- rated from the aqueous.layer below waB dried and then boiled constantly at 175' C. Submitted to analysis it gave the follow-ing results :-I. -1858 grm. gave -3991 grm. carbonic anhydride and -1663 grm. water. 11. .3322 grm. gave -7152 grm. carbonic anhydride and -2886grm. water. FRANKLAND AM) DUPPA'S These numbers agree with the formula aB shown by the following comparison :-Found. Calculated. 1 I. n 11. % Mean. C .... 60 58.82 58.58 58.72 58.65 H, .... 10 9.80 9-94 9.65 9-80 0 .... 32- 81-38 .. .. 31-55 7- 7- 102 100.00 100~00 Isopropacetic acid is a colourless transparent oily liquid somewhat soluble in water to which it imparts both its odour and strong acid reaction. Its odour cannot be distinguished &om that of valeric acid prepared &om amylic alcohol.Its specific gravity is -95337at 0' C. It boils at 175' C. and a de termhiation of ita vapour-density gave the following num-bers :-Weight of bopropacetic acid ........ ,1163grm. Observed volume of vapour.. ........ 50.77 c. c. Temperature of bath.. .............. 215' C. Height of barometer.. .............. 755-5 m.m. Difference of heights of mercury inside and outside of tube .............. 80.0 m.m. Height of spermaceti column reduced to millimetres of mercury.. ........ 16.9 mm. Hence the specific gravity of the vapour is 3'479 or one litre weighs 50.4criths. A two-volume vapour of' the above formula requires the numbers 3.52 and 51 criths.Isopropacetic acid diisolved in water boiled with argentic carbonate and filtered gives on evaporation in vacuo beautiful and very light pearly scales which are tolerably permanent in light and exhale an odour of the acid 100 parts of water at 10"C,. dissolve *187 parts of this salt. Dried over sulphuric acid this salt yielded on analysis the following numbers :-I *MOOgrm. gave *1876grm. carbonic anhydride 00700grm. water and *093P grm. silver. 11. *2194grm. gave -2312 grm. carbonic anhydride *OM3grm. water and -1136 grm. silver. SYNTHETICAL RESEARCHES ON ETHERS. These numbers agree closely with the formula as the subjoined comparison shows :-Calculated. I. 11. MfSL C .... 60 28.70 28.42 28.74 28.58 H .... 9 4.31 4.32 4.47 4.40 Ag ....108 51.67 0 .... 32 15.32- 51.88 .. 51-77 .. 51-82 15-20 209 100*00 100~00 In our formermemoir* we have entered fully into the chemical relations of the products derived fiom the duplication of the molecule of ethylic acetate; when the latter is acted upon first by sodium and afterwards by methylic or ethylic iodide. The corresponding reaction with isopropylic iodide described in the foregoing pages is so completely homologous with those ex- hibited by methylic and ethylic iodides as to render it super-fluous to enter into any theoretical considerations relating to the production of ethylic isopropacetone carbonate or of the ketone derived from it; but in order to prevent any misappre- hension of our views concerning the constitution of these bodies we here subjoin their graphic formule :-COEto Ethjiic isopropacetone carbonate.L@ I @-P * Phil. Trans. chi p. 37 and Jour. Chem. Soc ,vol. xix. 419. FRANKLAND AND DUPPA'S We have already mentioned that isopropacetone is isomeric with the ketone methyl-valeral obtained by Williamson in distilling a mixture of potassic acetate and valerate and also with etbyl-butyral. The origin of methyl-valeral indicates the probable constitution of that body whilst the cause of ita isomerism with isopropacetone is evident from the following constitutional formulae :-Isopropacetone differs from methyl-valeral in its boiling point which is 6" C. lower as might be anticipated from the boiling points of isopropylic and propylic alcohols which differ by 9" C.in the same direction. This difference of boiling point is doubt-less due to the difference in the constitution of the radicals propyl and isopropyl t.he former being a normal an$ the latter a secondary radical and as has been shown by Kolbe and our- selves normal compounds always boil at a higher temperature than their secondary iaomers. The temperatures of ebullition of the two radicals doubtless differ much more widely than those of their respective compounds ; and aB the atomic weight of the compound becomes proportionally greater with regard to that SYNTHETICAL RESEARCHES ON ETHERS. of the radical this difference becomes less and less appreciable. Unfortunately we are not acquainted with the specific gravity of methyl-valeral nor with its deportment towards hydric sodic sulphite.The production of ethyl butyral by the destructive distillation of calcic butyrate permits of no conclusions being drawn as to its rational constitution. Its behaviour with hydric sodic sulphite is not known but its boiling point 14' C. higher than that of isopropacetone proclaims its non-identity with the lnt ter substance. Two acids having the composition and atomic weight of valeric acid are now known viz. valeric acid or propacetic acid obtained by the oxidation of normal amylic alcohol and isopro- pacetic acid produced as above described. To these may be added a third which we have had for some time under investi- gation and the history of which we hope soon to be able to lay before the Society.This last acid is produced by the substitu- tion of the three atoms of hydrogen in the methyl of acetic acid by three atoms of methyl. These acids are represented by the following constitutional formulae :- FRANKLAND AND DUPPA'S Isopropketic acid. I Trimethacet,ic acid. I One other acid not yet obtained would complete this isome& group and would be produced by the aubstitution of two atoms of hydrogen in the methyl of acetic acid the one by ethyl and the other by methyl. Thils acid which might be appropriately liamed ethomethacetic acid would have the following constitu-tional formula :-m Y SYXTHETICAL RESEARCHES ON ETITERS. 115 In normal butyric and propionic acids we see the first step in the formation of this missing acid realised and the introduction of methyl into the first or of ethyl into ihe second in the place of cne of the remaining atoms of original methylic hydrogen would infallibly give rise to the acid in question.It will be observed on inspecting the above formulae that both valeric and isopropacetic acids are normal acids that is they both contain two atoms of undisplaced methylic hydrogen. The missing ethomethacetic acid would be a secondary acid because itwould contain only one atom of undisplaced methylic hydrogen whilst trimethacetic acid is a tertia.ry acid containing no undis-placed meth y lic hydrogen . The remarkable circumstance that both valeric and isoprop- acetic acid are normal acids led us to expect a very close resemblance between them and this anticipation has been com-pletely verified by a rigid comparison of the properties of the two bodies.In odour taste and general appearance they are quite undistinguishable from each other and the following table of comparison reveals no tangible difference between them :-Isopropacetic Valeric Acid. Acid. --Sp. gravity of liquid at 0" C. .............. -95357 -9555 (H. Kopp) Boiling point ........................... 175" C. 175" C. Specitic gravity of ether at 18" C. .......... *37166 -866 Boiling point of ether.. .................. 134°-136" C. 133.5' C. Silver-salt.............................. Nacreous Fcales Nacreous scales Solubility of silver-Ealt in water at 10" C..... 100 parts of water 100 parts of water dissolve '187 dissolve '1 80 Pad Pa* Had these acids been examined a few years ago no chemist would hsve hesitated to pronounce them identical on the fore- going evidence but the present state of our knowledge regad- ing the constitution of carbon compounds renders such an opinion utterly unt,enable. Nevertheless we were unwilling to leave the evidence of their difference upon a theoretical basis only and we have had the satisfaction of discovering a sharply defined physical difference between them. This difference is exhibited in their behavioiir towards circularly polarised light. The synthesized acid is inactive whilst valeric acid prepared 116 FRANELAXD AND DIJPPA'S .SYNTHETICAL RESEARCHES.from amylic alcohol powerfully rotates the plane of polarization to the right. We have also ascertained that the same differ- ence extends to their respective ethers. Professor Wanklyn has kindly titrated the ethylic valerate used for this experiment and has proved it to be of a purity almost absolute and free from amylic alcohol which moreover rotates the plane of polarization to the left Two experiments gave 30.17 parts and 30.15 parts as the amount of potassium necessary to displace the ethyl in I00 parts of this valeric ether. Theory requires 30.08 parts. Wurtz* states that valeric acid is inactive towards the polarized ray whilst we find that this acid possessea a tolerably powerful right-handed rotation. Our valeric acid was prepared fiom a sample of amylic alcohol which possessed a left-handed rotation.Past eur has shown? that ordinary amylic alcohol contains two varieties capable of being separated from each other; one of these is inactive whilst i~ stratum of the other 50 centimetres thick exhibits a lefbhanded rotation of 20°. It is highly probable that the active amylic alcohol gives active valeric acid and the inactive alcohol an inactive acid in which case the inactivity of Wurtz's sample of valeric acid would be explained on the supposition that it waa prepared from a sample of amylic alcohol containing only the inactive variety. We are at present engaged in the elucidation of this question with the view of ascertaining more especially whether or not the inactive amylic alcohol contains isopropyl and there-fore possesses the constitutional formula * Ann.Ch.Phys. xliv 275. t Compt. rend. xli 296 and Ann. Uh. Yharm. xcvi 265.