CCLIIL-The Preparation of the Ketones of the Higher Fatty Acids. by THOMASIIILL EASTERFIELD and CLARAMILLICENT TAYLOR (New Zedand Government Research Scholar)

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2298 EASTERFIELD AND TAYLOR: THE PREPARATION OF Published on 01 January 1911. Downloaded by University of Pittsburgh 15/05/2016 21:46:34.

CCLIIL-The Preparation of the Ketones of the Higher Fatty Acids. By THOMASIIILL EASTERFIELD and CLARAMILLICENT TAYLOR (New Zedand Government Research Scholar). THE distillation of barium and calcium salts, although of general application as a method for obtaining ketones, suffers from the drawbacks that large quantities of salt cannot be conveniently treated in one operation, and that the yield of ketone is often unsatisfactory. Krafft (Ber., 1882, 15, 1712) has shown that with fatty acids of high molecular weight the yield is improved by View Article Online

THE KETONES OF THE EIGHER FATTY ACIDS. 2299

heating the salts under diminished pressure, and Young (Trans., 1891, 59, G21) obtained no less than 80 per cent. of the theoretical yield of the ketone of phenylacetic acid by controlling the tempera, ture at which the calcium salt was decomposed, and ensuring the rapid removal of the volatile products of the reaction. Kipping (Trans., 1890, 57, 532) obtained a 40 per cent. yield of stearone by heating stearic acid with phosphoric oxide. This very convenient method is, however, inapplicable to the higher unsaturat.ed fatty acids. The observation (Easterfield and Bagley, Trans., 1904, 85, 1244) that in the presence of iron filings abietic acid is readily deprived of its carboxyl group with formation of a hydrocarbon suggested that iron filings might determine the formation of ketones from fatty acids at comparatively low temperatures. This is actually the case with the acids from lauric to melissic acid; thus stearic acid gave an 80 per cent. yield of stearone when heated with powdered castriron turnings to 360-370° for a period of three hours. The hitherto undescribed ketones of the higher fatty acids can be prepared by the same process, but owing to decomposition the yield is not so good. There can be little doubt that a ferrous salt is first formed, and that this then undergoes decomposition. Ferrous stearate heated to 360° slowly decomposes, and yields about 60 per cent. of stearone. No satisfactory yield of ketone was obtained by the interaction of iron turnings and acetic, butyric, phenylacetic, benzoic, suberic, and sebacic acids, or with the acid ester of sebacic acid. The observation that ketones may result by the interaction of acids and metals was first made by Liebig and Pelouze, who obtained acetone by passing the vapour of acetic acid through a heated iron

Published on 01 January 1911. Downloaded by University of Pittsburgh 15/05/2016 21:46:34. tube, but obtained negative results when a porcelain tube was employed. Jahn (Ber., 1880, 13, 2107) obtained acetone and impure butyrone respectively by passing the vapours of the corm sponding acids over heated zinc dust. HBbert (Compt. rend., 1903, 136, 682) obtained a mixture of stearone with solid and liquid hydrocarbons by distilling stearic acid with magnesium powder at as low a temperature as possible. Finally, Mailhe (Bzcll. SOC.chim., 1309, [iv], 5, Sl6j found that ketonw are the chief produch of the interaction of the vapours of the lower fatty acids, from acetic to nonoic acid, with many reduced metals, including such feebly electropositive metals as lead and copper, which in the form of ordinary filings are almost without actiqn on the fatty acids. The formation of stearone by the action of iron on stearic acid probably accouub for the fact recorded by P. W. Robertson (Trans. N. 2. Znst., 1904, 576) that the last runnings in the commercial 7~2 View Article Online

230G EASTEHFIELD AND TAYLOR : THE PREPARATION OF

distillation of stearin are so rich in stearone that the melting points of successive portions of the distillate fall rapidly to a eutectic and then rise with even greater rapidity. Examination of the higher distillates obtained in the refining of '' distillation " olein shows that they similarly contain oleone.

EXPERIMENTAL. Preparation of Stearone.-Pure stearic acid was heated with one- tenbh of its weight of sifted, clean cast-iron turnings to 280°, at which temperature the evolution of carbon dioxide became per- ceptible. The temperature was then raised slowly to 360°, and maintained between 360° and 370° for two hours. After removal of the iron and free acid, the ketone was twice crystallised from light petroleum (b. p. 100-120°), with the addition of animal charcoal, and it then melted at S8O. (Found, @=82*71; R=14.01. Calc., C=83*00; €I-13-83 per cent.) The yield of crude stearone melting at 85O was 80 per cent. of that demanded by theory. In dealing with large quantities of stearic acid it is advisable to raise the temperature rapidly to about 300°, and then to be very cautious about the further rise of temperature, it9 a sudden frothing sometimes commences at 320-330O. The following table shows the comparative yields of stearone in a series of experiments made with the object of ascertaining the most suitable conditions of reaction. Column 1 gives the quantity of iron employed, expressed in terms of that theoretically required for the conversion of the whole of the acid into ferrous stearate. Columns 2, 3, and 4 give the percentage of the theoretical yield of ketone formed at the temperature indicated.

Published on 01 January 1911. Downloaded by University of Pittsburgh 15/05/2016 21:46:34. Perceu t age Yield Yield Yield of iron. at 330". at 360" at 365". 100 53 62 80 66 35 53 74 33 3 34 - 20 - 28 - Undtered iron remained in the experimenta in column 4, and increase in the relative quantity of iron beyond the theoretical quantity did not improve the $eld of ketone. The experiments were carried out as follows : Test-tube8 contain- ing 1 gram of stearic acid and the requisite quantity of powdered cabiron turnings were heated in a Lothar Meyer air-bath for three hours, the last 50° rise of temperature being allowed to occupy one hour, at the end of which time the evolution of carbon dioxide had practically ceased. The product wm treated with acid and alkali, and then once crystallised from alcohol, weighed, and bhe View Article Online

THE KETONES OF THE HIGHER FATTY ACIDS. 2301

melting point taken. In no case did the melting point differ by more than 4O from that required for the pure ketone. Very little ketone is formed if stearic acid or calcium stearate is heated to 360' or if stearic acid is heated with metallic iron at temperatures below 300O. A sample of ferrous stearate prepared by adding ferrous acetate solution to an alcoholic solution of sodium acetate gave on analysis : Fe=8*9. Calc., Fe=9'0 per cent. This was heated to 360° for three hours, and the mass extracted with boiling alcohol; a 60 per cent. yield of stearone was obtained. Manganese stearate under similar conditions yielded 42 per cent. of ketone. Good yields, up to 65 per cent., have been obtained by substi- tuting aluminium and. manganese for iron in the above operation.

Dih eptade cyl car b inol, (C,,H&CH*OH. The attempt to reduce stearone by means of ethyl alcohol and a very large excess of metallic sodium was unsuccessful, practically the whole of the ketone being recovered unchanged. Even with sodium and boiling amyl alcohol the reduction takes place but slowly. One gram of stoarone ww dissolved in 200 C.C. of boiling amyl alcohol, and 8 grams of sodium were added in small portions at a time during a period of eight hours. The carbinol which crystallised out on cooling was recrystallised from amyl alcohol, and melted at 89.5". It is much more soluble in ethyl alcohol than the ketone from which it is prepared. The acetate prepared from the carbinol melted at 54-61O. Lack of sharpness in the melting point was observed by Kipping (Trans.,

Published on 01 January 1911. Downloaded by University of Pittsburgh 15/05/2016 21:46:34. 1890, 57, 987j in the case of dipentadecylcarbinyl acetate prepared from palmitone, and the same phenomenon is noticed in the acetates of the carbinols obtained from cerotone and montanbne : 0.1240 gave 0.3674 CO, and 0.1517 H,O. cT= 80.80; H = 13-54. C&H,,O, requires C= 80.73; H = 13.45 per cent.

Cerotone, C,,H,&. According to Beilstein (Vol. I., p. 1006), cerotone was obtained by Briickner by the distillation of lead cerohte, and melted at 62O, but the ketone prepared by Nafzger on distillation of the free acid melted at 92O. Mr. T. Rigg, M.Sc., kindly undertook the investigation of the action of iron turnings on cerotic acid, and supplies the following note. The cerotic acid was prepared from beeswax by combining the methods of Brodie and of Marie, and melted at 77'5O (uncorr.). View Article Online

2302 EASTERFIELD AND TAYLOR : THE PKEPARATION OF

Nine grams of the acid were heated with 0.69 gram of sifted cast-iron turnings, the temperature being allowed to rise to 350°, at which temperature the mixture was maintained for four hours. Evolution OP carbon dioxide began at about 280O. After removal of iron and unchanged cerotic acid, the product of the reaction was recrystallised from light petroleum (b. p. 80-looo) until the melting point was constant. The yield was 55 per cent.; in a second experiment, in which the temperature wits maintained at 360° for three hours, a 70 per cent. yield was obtained. Cerotone prepared in this way melts at 93O; it is moderately soluble in light petromleum or ethyl acetate. It separates from hot glacial acetic acid in feathery groups of crystals. In hot ethyl alcohol it is almost insoluble, the solution merely becoming slightly turbid on cooling. (Found, C = 83.50 ; H = 13.93. Calc., C= 83.80 ; H = 13-97 per cent.) Dipentecosylcarbinol, (C2,1351),CH*OH, prepared by reducing cerotone with sodium in boiling amyl-alcoholic solution, melted at 95O. The acetate prepared from this alcohol melted at 58-60°: 0.1068 gave 0.3207 CO, and 0.1315 H,O. C=81*89; H=13*67. C,,H,,,O, requires C= 82-17; H = 13-69 per cent. Cerotoneoxime, (C2,H,l)2G:NOH, was prepared by boiling 1 gram of cerotone dissolved in 150 C.C. of amyl alcohol with 2 grams of hydroxylamine hydrochloride and excess of potassium hydroxide. It wm crystallised from ethyl acetate, and melted at 78O: 0.1227 gave 0.3696 GO2 and 0.1505 H,O. C=82*15; H= 13.61. 0.44 ,, NH, equivalent to 4.95 C.C. NIlO-HCl. N=1.58. C,,H,,ON requires C= 82.14 ; H = 13.82 ; N = 1.87 per cent. Published on 01 January 1911. Downloaded by University of Pittsburgh 15/05/2016 21:46:34.

Moiitanic acid, prepared from Montan wax, was recrystallised from alcohol, and finally from glacial acetic acid until the melting point was constant at 82.5O (uncorr.). The titration value of the acid agreed sharply with that required for an acid of the formula C,I€,@,, as stated by Ryan and Dillon (Sci. Proc. Roy. Buhl. Soc., 1909, 12, 202), not with C2,H5,O,, as given by Hell (Zeitsch. angeio. Chem., 1900, 14, 556) and by Eisenreich (Chem. Rev. Fett. Barz-Znd., 1909, 16, 211). The ketone was prepared as in the case of stearone, a 50 per cent. yield being obtained. It melts at 97O, and is conveniently recrystallised from glacial acetic acid : 0.1124 gave 0.3456 CO, and 0.1415 H,O. C=83*85; H=13*98. C55H1100 requires C = 83.96 ; H= 13*97per cent. View Article Online

THE KETONES OF THE HIGHER FATTY ACIDS. 2303

Monta~toneozi~nemelts at 82*5O, and is very sparingly soluble in alcohol, more readily so in ethyl acehte: 0.3371 gave NH, equal to 4.2 C.C. NIlO-HCl. N=1*74. C,,H,,,ON requires N = 1-72?per cent. The alcohol obtained by reduction of montanone melts at 101O; the corresponding acetate melts at 66O.

Melissone. The melissic acid was prepared from New Zealand beeswax, and was separated from the cerotic acid by means of the very sparing solubility of sodium melissate in hot 95 per cent. alcohol, in which solvent sodium cerotate is rather easily soluble. The acid melted at 88-5O (uncorr.). The ketone was prepared by heating the acid with metallic iron for two hours at 370O; the yield was 47 per cent. of that demanded by theory. Melissone melts at 99.5O, is practically insoluble in boiling absolute alcohol, but may be conveniently recrystallised from amyl alcohol or glacial acetic acid: 0*0804 gave 0-2489 CO, and 0*1018 H20. c(=84.32; H=14*06. C,,H,,@ requires C = 84.08 ; H = 14.01 per cent. Schwalbe (Biss., Tubingenj observed a ketone melting at 97-99O amongst the products of the soda-lime fusion of myricyl alcohol from beeswax. Melissoneoxime melts at 84O.

Oleone, C3&&6O. Published on 01 January 1911. Downloaded by University of Pittsburgh 15/05/2016 21:46:34. According to Beilstein (Vol. I., p. 1006) no ketones have hitherto been prepared from the unsaturated acids, C,H,, - 2Q. In Watt’s Dictionary (Vol. IV., pp. 193 and 196) it is stated that Bussy obtained a neutral, oily liquid by distilling oleic acid with lime, and that he regarded this as oleone. Attempts to prepare oleone by the interaction of oleic acid and phosphoric oxide were unsuccessful, a viscid tar resulting, from which no definite com- pounds could be extracted by organic solvents. Oleone can, however, be isolated from the distillation products of barium oleate, and more readily from the reaction product of iron with oleic acid. It is also present in the fractions of highest boiling point of commercial oleic acid. 1.-Forty grams of barium oleate (Found, Ba=19*4. Calc., B;t=19.6 per cent.), recrystallised from a mixture of benzene and alcohol (Farnsteiner, Zeitsch. Nahr. Gemssm, 1899, 2, l), were View Article Online

2304 EASTERFIELD AND TAYLOR: THE PREPARATION OF

heated in a flask immersed in a bath of molten solder. A slow current of hydrogen was passed into the flask throughout the operation, and the pressure was kept below 100 mm. A device similar to that used by Young (Trans., 1891, 59,623) was employed Lo remove the volatile products as rapidly as possible. A distillate first appeared at 280°/25 mm., and was pale yellow and mobile. As the temperature rose, the distillate became darker and more viscous, and the pressure in the apparatus rose. Distillation ceased, and the pressure again fell before a temperature of 450° was attained. The total distillate was a reddish-brown, viscous liquid showing a green fluorescence. A small quantity of crystals separated on keeping, and a further crop was obtained by frac- tionating the crude distillate under diminiahed pressure and cooling the fraction distilling between 280° and 330°/5-10 mm. The total weight of crystals was only 2 per cent. of that demanded by theory for the production of oleone from the barium salt, After repeated crystallisation from alcohol the substance melted at. 59”: 0.1062 gave 0.3252 CO, and 0.1260 H,O. C=83-3; H=13*1. By ebullimcopic method in alcohol : Found, M.W. = 492 and 508. C,H,,O requires C = 83.66 ; H = 13-14 per cent. M.W. = 502. The bromine absorption in chloroform solution after twelve hours was 62.1 per cent. The absorption of four atoms of bromine requires 63.8 per cent. It is, of course, possible that in the formation of this oleone the position of the ethylene linkings may have changed from the positions occupied in the oleic acid. It is not a little remarkable that the distillate boiling at 280--330°, from which the oleone crystals have been removed as far Published on 01 January 1911. Downloaded by University of Pittsburgh 15/05/2016 21:46:34. as possible by cooling and filtration, still ha8 almost the same composition as the crystals themselves. (Found, C = 83.2 ; R=13-0.) This calls to mind an observation by Miller and Tschitschkin (Anrwlen, 1899, 307, 375) that the distillate from the calcium salt. of azelaic acid yields a fraction boiling at 180-200°, the analysis of which agrees with that required for cyclooctanone; but the existence of this compound could only be proved in the fractions boiling above 2OOc. 11. Prepctmtion of Oleone by the Znteraction of Zron and OLeic Acid.-One gram of oleic acid prepared from the commercial acid by repeated rectification in a vacuum and removal of saturated fatty acids by freezing, and 5 grams of practically pure oleic acid (prepared from olive oil, solidifying completely at 14O, and yielding it lead salt completely soluble in ether) were separately heated with one-tenth of their weights of powdered and sifted casbiron turnings. View Article Online

THE KETONES OF THE HIGHER FATTP ACIDS. 2305

Evolution of carbon dioxide began at 240O. The mixture was slowly heated to 340°, and this temperature maintained for two hours; much frothing occurred towards. the end of the reaction. After remova.1 of iron and acidic substances, the semi-solid product was crystallised several times from alcohol and acetic acid until the melting point was constant at 59-5O. The yield in each case was 10 per cent. of the oleic acid taken: 0-1089 gave 0.3335 CO, and 0.1332 H,O. C=83*5; H=13*6. C,,'H6,0 requires C = 83.6 ; H = 13.1 per cent. From oleic acid heated to 340O for two hours in the absence of iron no oleone could be isolated. 111. Isolation of Oleone from Commercial Oleic Acid.-Since commercial olein is prepared by the steam distillation of crude stearin from cast-iron retorts, the temperature in which frequently exceeds 300°, the presence of oleone is to be expected in commercial oleic acid. By the kindness of the directors and manager (Mr. Bull) of the New Zealand Candle Co. we have been supplied with samples taken during the redistillation of 2 tons of commercial olein, an operation extending over five hours. The fractions collected .during the first four hours distilled almost completely below 270"j50 mm. The portions passing over during the la& fifteen minutes were filtered from solids, and only began to boil at 2iO0/5O mm.; a iarge portion boiled above 300°/25 mm. Oleone was obtained from these higher fractions by dissolving in a large volume of alcohol and neutralising with sodium hydroxide, which caused the separation of an oil insoluble in the soap solution. This oil on keeping deposited crystals, which melted at 59O after repeated crystallisation from alcohol and acetic acid. oleone Published on 01 January 1911. Downloaded by University of Pittsburgh 15/05/2016 21:46:34. When prepared by any of these methods is a colourless substance, crystallising from alcohol or acetic acid in hair-like needles. It is sparingly soluble, even in boiling alcohol, more readily so in ether, ethyl acetate, glacial acetic acid, or chloroform. Oleoneoxime melts at 3lC,and is readily soluble in alcohol:

0.1334 gave 2.9 C.C. N, at N.T.P. N=2.73. C,EI,,ON requires N = 2-70 per cent. Reduction of Oleorbe to Peiatci triacontane.A.5 Gram of oleone was warmed with phosphorus pentachloride, and the product sub- sequently reduced with hydriodic acid and phosphorus at 240O. The resulting hydrocarbon was recrystallised from ether, and melted at 73O. (Found, C=85-8; Hr14.8. Calc., C=85*3; H=14.6 per cent.) Pentatriacontane melts at 74"7O (KraEt, Ber., 1882, 15, 1715). View Article Online

2306 PREPARBTIOX OF KETONES OF THE HIGHER FATTY ACIDS.

Elaidone. Two grams of pure elaidic acid were heated with iron under similar conditions to those employed for the preparation of oleone. The elaidone was recrystallised from alcohol, and melted at 70°. The yield was only 15 per cent. when the maximum temperature employed was 320O; a larger yield was obtained in an experiment in which the maximum temperature was 350°, but the ketone produced at the higher temperature was not readily brought to a sharp melting point by recrystallisation : Found : C = 83.33 ; H= 13.27. C35H66Qrequires (=i=83*62;H=13'14 per cent. Elaidoneozime crystallises from alcohol in long needles, which melt at 32O ;it is more readily soluble than the oxime of oleone : 0.3678 gave NH, equal to 7.8 C.C. N/10-HCI. N=2.96. C,,H,,ON requires N=2*71 per cent.

Brassidone. This was prepared from brassidic acid and metallic iron, and melts at 80°. The yield at 280° was 20 per cent., at 320° 50 per cent., of the acid employed. The compound is readily soluble in hot alcohol : 0.1237 gave 0.3787 CO, and 0.1495 H,O. C=83*42; H=13*42. C4,HS2O requires U= 84.03 ; H = 13.33 per cent. Brassidoneoxime melts at 51° : 0.3078 gave NH, equal to 4.6 C.G. N/lO-HCl. N=2.19. C,,ES,ON requirw N = 2-22 per cent. Published on 01 January 1911. Downloaded by University of Pittsburgh 15/05/2016 21:46:34. Action, of Iron on Emcic Acid. Carefully purified eruric acid was heated with powdered iron turnings for three hours a.t 300-320O. The resulting neutral compound, even after repeated recrystallisation from a variety of solvents, melted at 50-60°, although the analytical numbers agreed with those required for erucicone. (Found, @= 83.88 ; H = 13.54. C,,.H,,O requires C=84-04; H=13*33 per cent.) From the products of distillation of barium erucate under diminished pressure a similar product of indefinite melting point was obtained. The result would be readily explained if, during the process of heating, a portion of the erucic acid were changed into any of the mmerous possible isomerides, so that the ultimate product would be a mixture of isomeric ketones. Some support in favour of this view is given by the observation View Article Online

THE SEPARATION OF MIXTURES OF ORGANIC ACIDS, ETC. 2307

that a sample of the same erucic acid when heated alone for two hours at 2t30-3OOc yielded a mall quantity of an acid melting at about 50°. The original erucic acid melted at 34O.

The expenses of this investigation have been defrayed by a grant from the Research Scholarship Fund of the Government of New Zealand. VICTORIACOLLEGE, WELLIXGTON,N.Z. Published on 01 January 1911. Downloaded by University of Pittsburgh 15/05/2016 21:46:34.