ON THE ALCOHOLS O F FUSEL OIL.
BY ROBERTC. S C H ~ P P H A U S . About a decade.ago fnsel oil or commercial amylic alcohol could be procured for little more than the cost of cartage. In those days it was chiefly used in the manufacture of alkaloids, especially quinine. The quantities consumed in the preparation of valeric acid and its salts and various amylic ethers were unimportant. The conditions abroad were about the same. Thongh fusel oil was repeatedly proposed as a substitute for alcohol in the manufacture of spirit varnishes, its application did not meet with favor, both on account of its odor and its comparative lack of volatility. I n the production of coal tar dyes i t has been but rarely employed. Cyanine or quinoline blue is obtained by treating quinoline with amyl iodide and subsequently treating with an alkali. Amyldiphenylamine furnishes, on heating with oxalic acid, a bluish green dye. T h e iodide and chloride of amyl required in these processes were prepared from fusel oil. In t h e manufacture of methyl green from methyl violet our method of purifying the dye stuff consisted in dissolving the crude product in water and agitating the solution with amyl alcohol, which dissolves the green, leaving the violet in the aqueous solution. All these processes are obsolete. H. Briem* recommended the fusel oil from the fermentatioii of beet-sugar molasses as a crude material for the production of illuminating gas of superior qnality, and in 1880 lie+ reported that several factories had introduced the process, among others a distillery. T h e latter concern enjoyed, of course, special facilities, putting a value of only eight cents a gallon on the material R. v.
* Organ des Centra>l-Vereins fur Rubenzucker-Industrie in der Oest. Ung. Monarchie, 1877, p. 180, 1879, p. 265. tIb., 1880, p. 20.
W;ignci~"comments o n Briem's proposition as follows: I t sems to me its if fusel oil could be utilized for something better tlmn makiiig gas. If tliere is 110 hotter outlet. let it rittlier go to wa,ste. a1id wait for better times." Anrl 1x:ttet. times did come. J n lSSS ,Joliii 11. Stevetist introduced. fusel oil iis :i substitute of graiii al. coli01 in tlie munufacture of ccllnloicl. T h e misturc of alcohols coiistituting fusel oil forms, in coli junction with camphor, a n e f i cient solvent of iiitrocellnlose, es1)eci:illy at elevated temperatures. In this coriiiection it is worthy of note, t h a t hrthiir H. Elliott,l i l l liis intercsting paper 011 nitro-saccliarosc, mentions amyl alcohoi as a solveiit .of this sob&nce. From the very discovery of pyroxgline inore or less successfnl attempts liad been made to employ it its a base for wrnislies. Bat the pyrosyline varriisli industry did iiot begin to flourish until amyl acet:tte was utilized as a solvent, wliich JWS in lS':9. *Jolin €1. Stevens11 patented its iisc i i i tlie matiuf:tcture of celluloid in IS?. Otto 1'. d n i e n d $ iiit,roclnced, in 1SS7, for similar purI)oses, tlic products of cliloriiintioii of amyl iilcoliol ailel :icetwte. I11 1SS4 I founcl that pure amyl ;ticoho1 is far less useful in tlie manufitcturc of celluloid than the i:oniniercial article, wliicli observiitioii led me to tho cliscovcrg tlint propyl aiid isobutyl :ilcohols are to be preferred to the liiglicr lioniologue.** RZistii!cs of propyl and biityl alcohols can be procured at very moderate priccs in Eiirope~iiimarkets. At tlic same time 1 proposed propyl slid butyl :tcetates for the rnunufacture of pyrosyliiie v;imishes. \\:alter D. Ficldtt obt:iiued :t p a t e n t for sucli variiislies in 1SS7. Large qwntities of the acetates of propyl, butyl wid i(
* \V'agncr's
Jaliresb., 1879, p. 1216.
4 U. Y. Patent 209,343, D e c e n h r 10tli, 1882, filed JLUKl2tli,
1882.
:This Journal, 4 (1882), 147.
I/ U. S.Patent
269,340, Dee. 19th, 1883, filed J a n e E t h , 1882.
L-, S. Patcnt 371,081, October A t h , 1887, filed JIuy Iltli, 1887. U. 8. PiLtent 378,100, Oct. %tli, 1887, filed K t y 4tli, 1887. U. S . Reissue 10,879, Yor. 8tl1, 1887, Iilecl Oct. 15th,1887. *r U.S .
Pntcnt 410,204, Ycpt. 8d, 1884, filed Oct. IWh, 188ti.
ft U. S. Patent 381,354,
April l X h , 1888,filed ;lugnst 13tii, 1887,
O S T H E ALCOHOLS OF FUSEL OIL.
47
amyl are consumed in the manufactnre of photographic films. Amyl acetate has also been used in t h e preparation of some of t h e smokeless powders, the Wettern, for instance. The burning fluid in IIefner’s standard lamp for photometric purposes is amyl acetate. The acetate, butyrate and valerate of amyl enter into the composition of t h e artificial fruit essences and flavors. A few years since they found an ephemeral application in perfumery, when fashion, in one of her capricious moods, decreed that t‘he delicate scents of flowers must yield to the more substantial odors of fruits. E. Liebert* adds amyl nitrate to nitroglycerine to diminish its sensitiveness to cold and concussion. A variation of his process consists in mixing glycerine either with amyl nitrate or amyl alcohol before subjecting i t to the action of t h e nitrating mirtnre. Bniyl nitrate is employed in medicine ; in the chemical laboratory it serves in the preparation of diazo and kindred compounds. T h e analyst makes m e of pure amyl alcohol in the separation of alkaloids. Isobntyl alcohol or i t s chloride is employed in the manufactnre of the nrtificial mnsks, trinitro derivatives of butyltoluol and bntylxFlol. Valeric acid is obtained throngh the oxidation of amyl alcohol. ],e Belt described :L method of prepnring inactive amyl alcohol from the fermentation product, and showed that valeric‘acid from this source is identical with the officinal acitlirui r.ccl7o.in,iicicni c m d i c e p r a t n , a fact all the more important as the valerates made from active alcohol will not crystalize. Hydrated valeric acid, and the valerates of ammonium, EOdium, iron, zinc, bismuth and quinine are well known remedies. Pental (one of the amylenes), an aneesthetic, and hydrate of amylene, a hylmotic, are both derived from amyl alcohol. Prior to 1E58. arnylece was employed in dentistry, but owing to imperfect methods of manufactnre, fell into disrepute. Fusel oil yields, on heating with zinc clilnricle crude amylene, mliicli. through trent111e t i t .si th si111jli 11I’i c ac id and si1bseq uc~n t d ec om 1iosi t i on wit 11 IV ater is converted into amylene Iijdrate or teitia1.y amyl nlcoliol.
*D.R. P. ,71022, of 3Iarch ?9tli, lF88. 4 Conipt. Rend. 8G (lSis),213.
45
ON T H E ALCOHOLS O F FVSEL O I L .
This alcohol, when heated with dilute sulphuric acid, furnishes pure amylene or pental," i. e., trimethyl ethylene, B. P. 38" C. This enormous increase in the consumption of fusel oil, or its separate constituents, has brought it about not only that the domeetic article finds a ready market, t ~ u t ,that large quantities are imported from abroad. B u t whilst the co~isumption is steadily on the increase, the production does not keepstep with it. One gallon to each t h e e hundred of crude spirit may be said to be the average yield, and from this a large quantity of ethyl alcohol may be extracted by cautious distillation. Xoreover, every progressive distiller bends his whole energy to counteracting its formation, and Linnet's* researches, and Springer'st method of producing alcohol point to success in this direction. I t must be borne in mind, however, that with free alcohol for t h e arts ; ~ n dmanufactures the use of fusel oil would be abandoned in several branches. Fusel oil was discovered by ScheeleT in the tailiugs from the rectification of rye whiskey. Pelletanjl obtained and examined a similar product from potato spirit. I n the revised edition of Watts' Dictionary of Chemistry fusel oil is defined as a yolatile liquid present in the product of the alcoholic fermentation of the saccharine liquids derived from potatoes, wheat, etc., and of the juice of grapes, beets, etc. I t passes over in the latter portion of the distillate when these liquids are rectified. Fusel oil always contains amyl and ethyl alcohols, usually isobutyl and n. propyl alcohols, some fatty acids and some ethers. The three higher alcohols mentioned became first known to science through the examination of fusel oils. Dumas8 isolated amyl alcohol, B. P. 131.5", from potato fusel oil and ascertained its percentage composition, without recognizing, however, its alcoholic mture. Cahours** investigated the ('
"Compt. Rend. 112 (1891), 663. t Scientific American Supplement of Sept. 26th, 1891, p. 13125. $ Crell's Ann., 1785, I. 61. /I Ann. Chim. phys. [l] 30 (1825), 221. $ Ann. Chim. phgs. [11 56 (18341, 314. ** Compt. Rend. 4(1837, 341, and Am. Chini. phys. 113 70 (1839) 81, and [l] '75 (1840). 193.
O S THE ALCOHOLS O F FUSEL OIL.
49
same product and showed that it was a substance analogous to common alcohol and belonging to the same natural series of which methyl and ethyl alcohols form the first two members. Balard* obtained it from the fusel oil formed in the fermentation of grapy skins, and prepared quite it series of amyl compounds. I n 8 fusel oil of the same origin Chancelt discovered n. propyl alcohol. Wurtzf made the discovery of i-butyl alcohol in his investigations of fusel oils from potatoes and beet-sugar molasses. The analytical chemist may regard fusel oil for all practical purposes as a mixture of water and ethyl, propyl, butyl and amyl alcohols. The quantity of ethers present, mostly amylic ethers, is usually minute. Kolbe,II TVurtzS and Perrot** examined the ethers and fatty acids of fusel oil. Whilst in the crude product amyl alcohol preponderates, the composition of distillates varies greatly. Instances of fusel oil free, or nearly free, from amyl alcohol as reported in chemical literature, e. g., by H. Briem,tt do not bear close scrutiny. One such case$$ mentioned I found on consulting the origina1,IIII to refer to a distillate. This liquid, boiling a t about 100" C., consisted of ethyl, propyl and chiefly isobutyl alcohols, with only very little amyl alcohol, and had been obtained from a large quantity of fusel oil by fractional distillation with the aid of a column. G . L. UlexSS described, in 1873, a valuable method of determining the amount of ethyl alcohol in fusel oil, and incidentally remarked that ':wine " fusel oil contains no amyl alcohol, because *Ann. Chim. phys. [3] 12 (1844). 294.
t Compt. Rend. 37 (1853), 410. SCompt. Rend. 35 (1852), 310, and Ann. Chim. phgs. [3] 42 (1854),129. 1 Ann. 41 (1842), 53. $ Ann. Chini. phys. 131 43 (1854), 129. ** Compt. Rend. 45 (1857). 309. tt Organ des Central Ver. f. Rubenzncker-Ind. Oest. Ung. Monarchie 1877, p. 180. $$Wagner's Jahresb,, 1875, p. 882. 1111 August Freund, J. f. pr. Chem. X. F. 12 (1875), p. 25. $8 Dingler's polyt. Journal, 208, 379.
50
ON T H E ALCOHOLS OF FUSEL O I L .
all of it passes over below 130" C. when subjected to distillation Such superficial argument cannot convince the student who has ever investigated fractioiial distillation, especially as applied to such a complex mixtnre of analogous substances as represented by fusel oil. How imperfect a separation is effected by a single distillation of even so simple a mixture as amyl and ethyl alcohols, the boiling points of which are the farthest apart of all t h e substances concerued in this discossion, may be gathered from a communication i n ( I .\ 'l'reatise on Chemistry," by Roscoe and Schorlemmer." -1. further complication eusues when the liquid contains water, as all commercial fusel oil does, and dehydration previous to anylpsis is neglected. A mixture of mater and amyl alcoho1,tB. P. 130", boilsat 96", and the distillateconsistsof two voliimes of water and three of amyl alcohol : in the case of butyl alcohol, B. P. 108", the boiling point I S lowered to 90.jc and the constituents pass over in the proportion of one volume of the former to five of the latter. In t h e light distillates of fusel oil the amount of water may rise to considerable proportions. Where a rational separation is aimed nt, complete dehydration is indispensable. l'he Governmcnt chemist is chiefly concerned in a rapid determination of ethyl alcohol in fusel oil. The time-honored British method consists in shaking the sample with an equal volume of water and taking the gravity of the separated aqueous layer. UlexJ was the first to call attention to the serious error committed iii calculating the percentage of ethvl alcohol from t h e gravity of the aqueous solution. He points out that commercial fusel oil is far from being a mixture of ethyl and amyl alcohols, and that the ready solubility of the lower alcohols is the cause of grave mistake-. The solubility of the alcohols chiefly concerned stands thus : 11-propyl alcohol is miccible with mater in all proportions.
* Vol. III., p.
117.
?Pierre and Puchot, Ann. Chin]. phys; 141, 22 (1868), 234. t i . c.
51
OS T H E A L C O H O L - CIF FYSEL O I L .
i-bntyl alcohol rcquires 10.5 parts of water for solution a t 1s" C. i-amyl alcohol reqiiires 30 parts of water for solntion a t 16.5" C. Vies distilled three different fusel oils with the €allowing results : FCSELOIL FROM Beets.
Potatoes.
Rye.
Sp. gr. a t 15" C . _ _._ __ _.S?G _ ,832 .s37 80-100" C. - - - - - - - - 13$ by VOL 13$ by V O ~ . 31$ by ~ 0 1 . 266 '( 53s " 30$ " 100-13;cC 575 (' 435 34$ above 130" C , - - - .
.________ ____
('
((
From these figures lie coiiclndes that two-thirds of beet fusel oil consist of the more soluble alcohols, a conclnsion manifestly incorrect, as repented f~*actional distillations would have yielded larger percentages of high boiling components. Yeither does he rnentioii auy treatment to free the oils from water, though their gravities distinctly indicate its presence. I t must be considered that he is speaking 1tw dam, However. his data were snfficicnt to jnstify his attack on tlie British excise method, on the basis of which a fusel oil containing eight per cent. of proof spirit liad been declared to hold forty-four per cent. According to his nl'ethod 100 cc. of the sample is distilled until 5 cc. of distillate is collected. This is shaken with ai1 eqnal bulk of a saturated solution of sodium chloride. If one-half or more of fusel oil is separated. it may be taken for granted that less than fifteen per cent. of proof spirit are present, i. e., the sample is duty free. If, however, less or none separates, the sample tinder examination is slinkeii with an equal volume of a saturated solution of sodium cliloride, mliicli dissolves propyl and bntyl alcoliols much less readily than water does, ,and allowed t o settle. The aqueous layer is snbjecterl to distillation, and tlie gravity of t h e distillate 'is determined. Alfred H. -411en" de8cr'ibes a very rapid method yielding satisfactory results, when mixtures of ethyl and amyl alcohols only are concerned. After ngitntiug the sample in a graduated tube with
* Commercial Organic Analysis. 1'01.
I. (ISM), p. 179.
an e q n d volume of petroleum spirit, siitticieiit water is added to cause' st3l)ar:ition. The increase i l i the rolume of the petroleuni spirit ioilicates with :~l~proximxtc :iccurul:y tho imoiirit of :imyl alcohol. The German Excise* authorities eini~loythe following tests : I , 10 cc. of fusel oil are sliakcii \\,it11 30 ce. of calcium chloride solntioii of sp. gr. 1:!?5 (niadv from .!5 grins. of :inhydrous calcium chloride n11d 100 cc. of Trater). After o n e minute's agitation a t least ';..j cc. miist remain uiiilissolvcd. 2 . 100 CY, of fnscl oil must show :i decided turbidity, when shaken f u r Q ~ I Bmillute with 5 iic. of tlist~illcilwater.
I liit~-ehac1 occasion to examine sclveral samples of distillates of fnsel oil. A sample from ii famous German f m t o r j was anIiydrons. :tiid consisted of nothing but propyl and butyl alcohols. Another distillate froiii a X e w T o r k City firm Iiad a similar composition with only w r y little amyl alcoliol. Hut the most interesting ani1 somew11:it surprising results were revealed on a closer exnmimtion of several s a m i h from n factory: where large quantities of domestic :tiid foreign fusel oils are distilled. These liquids m r e gnaraiiteed to Le practically free from amyl alcohol, and a chemist, presumably more obliging thah erudite, certified to the fact, that they contained propyl alcohol ns tlieir chief constituent, and that on an awrnge not more than four per cent. of water was present. I n spite of this favorabie composition, and though they were used in conjunction with high grade wood alcohol, these fluids nere responsible for some liighly objectionable phenomena i n the manufacture of celluloid. T h e determinat.ion of their gravities slioivecl the presence of a large amount of water. If no dehydration had taken place previous to distillation, i t was to be presunied that all the alcohols of fusel oil would be present, which m y analyses p r o ~ e i to l be t h e case. To determine the quantity of mhter, 200 cc. of t h e sample -were shaken in a graduated cylinder with freshly calcined potassium carbonate. 3Iore carbonate was added, until no further diminntiori of volume took place. T h e gravity of the liquid was carefully * Wagner's Jahiesb. 1890. p . 1078
03’ T H E ALCOHOLS O F FTSEL OIL.
53
taken both before and after this operation. All the gravities were determined by means of a pycnometer. d simple calculation gives us the percentage of water with sufficient accuracy for technical purposes. F o r instance : ?OO cc. Sp. gr. .81?5=165.5 grms. leZtve 179 cc. Sp. gr. .SOD5=144.9 grms.
--
23.6 grms. of water. = 1 4 d by weight.
The larger quantities: required for fractional distillation were dehydrated in the same manner, the operation being repeated. A further treatment with quick lime produced no decrease in tlie gravity. Calcium cliloricle cannot lie reconimeiided for quantitative work, being noticeabl3 soluble even in the higher alcohols and tlins interfering with distillation. 250 grms.of tlie anhydrous liquid mere distilled from a flask fisted with a Glinsky column and connected with a long Liebig eoiidensei*, the rate of distillation being a drop a second. A pliltinnm spiral was immersed in the fluid to ensure regular ebullition. In the first distillation the portions passing orer between each fire degrees were collected separately, These fractionswere redistilled, and those portions mliicli boiled between the same intervals of temperature were united, the interval in all subsequent distillations being two degrees. In this manner fractions boiling a t 78-SO”, a t about 97’ and l o g 2 , and a t 123-132” mere obtained. The slight residue boiling above 132” possessed an odor suggestive of amyl valerate and probably consissed mainly of amylic ethers I append the results of rny analyses of four different samples.
I.
Clear yellow liquid of neut 11 reaction. Sp. gr. ,8425 a t 18. C. 100 grms. contain 1 .O of water. 30.0 f ethyl alcohol. 14.5 f n-propyl alcohol. 25.2 of i-butyl alcohol. 15.0 of fermentation amyl alcohol, 1 . 3 of residue.
54
ON THE ALCOHOLS U F FCSEL OIL.
11. Clear yellowish liquid of neutral reaction. Sp. gr. .8523 a t 19.5" C. 100 grms. contain '70.0 of water. 19.4 of ethyl alcohol. 11.7 of n-propyl alcohol. 24.9 of i-butyl alcohol. 22.0 of ferm. amyl alcohol. 2.0 of residue.
111. Slightly cloudy liquid of brownish tinge. Reaction neutral. Sp. gr. .8434 a t 21.5" C. 100 grme. contains 18.3 of water. 15.0 of ethyl alcohol. 8.2 of n-propyl alcohol. 19.9 of i-butyl alcohol. 36.8 of ferm. amyl alcohol. 1.8 of residue.
I\-. Colorless, clear liquid, of neutral reaction. Sp. gr. .8630 a t 16.5" C. 100 grms. contain 23.0 of water. 52.8 of ethyl alcohol. 5.'; of n-propyl alcohol. 11.0 of i-butyl alcohol. 7.0 of ferm. amyl alcohql. .5 of residue. I t is evident that these liquids are the resnlt of a simple distillation of fusel oil in the crudest kind of still. The temperature may never have exceeded 100". Kraemer and Pinner" found in the first runnings of fusel oil thirty per cent. of water, thirty per cent. of i-butyl, twenty per cent. of ethyl, and twenty per cent. of other alcohols, a good portion of which is n-propyl alcohol. Pierre and Puchott found in
* Bep. 2 (1869)401,
t Ann.
and 3 (1870), 75. Chim. phys. [4]22 (1868), 334.
ON THE ALCOHOLS OF FUSEL OIL.
55
the crude fusel oils examined by them on an average 16 per cent. of water, 2.5-3 per cent. of n-propyl, 3-4 of i-butyl, and a t least fifty per cent. of amyl alcohol. I learned later on that samples I. and 11. had been specially redistilled, that my analyses might show more of the lower alcohols and less of amyl than otherwise would have been the case. A mixture of these distillates with methyl alcohol, in the proportions as used in practice, yields a clear camphor solution. Without the woodalcohol part of the water separates on the addition of camphor, and this behavior accounts for the diaagreeable experience with these menstrua. Large blocks of celluloid, when cut into sheets, were found to be interspersed with cavities containing a liquiu, which proved to be chiefly water. Their pr'esence is easily explained when the peculiar composition of the solvent is considered. As stated, these liquids were represented to be free from amyl alcohol, and it became thus necessary to inrestigate the nature of the fraction 128-132". Its gravity was found to be ,8113 a t 19" C., i. e., the gravity of i-amyl alcohol. With metallic sodium a gelatinous mass mas obtained under copious evolution of hydrogen; on addition of water an oily iayer collected on top of t h e lye. Heated with sulphuric acid and sodium acetate, an ether of the characteristic smell and boiling point of amyl acetate was produced. These tests leave no doubt as to its nature. But the chief constituent was said to be propyl alcohol, and in view of Rabuteau's" researches on potato fusel oil it was at first thought possible that isopropyl alcohol might be contained in considerable quantities in the fractions of low boiling points. Isoprophyl alcohol is not totally freed from mater even by distillation over barium oxide, as Friede1,t who was the first to prepare i t from acetone, pointed out. Berthelot't the discoverer of the compound, obtained it by absorbing propylene in sulphuric acid and treating the solution with water. He founcl the boiling point of the alcohol, which was not quite free from water, a t 81-82O. The sepa-
* Compt. Rend. 87 (1878), 500.
t Compt. Rend. 55 (1862), 53. $Ann. Chim. phys. [3] 43 (1855), 385.
56
O S THE AI.COHO1.s
O F FUSEL O I L
ration had been effected by means of calcined potassium carbonate. Friedel's compound, boiled a t 84-S6,"after seyeral rectifications over barium oxide, a t SG-SF, after treatment with metallic sodium. I t is to be noted t h a t the acetoneused by him wasnot remarkably pure, being a by-product gained in the manufacture of aniline. The subject was fully in\-estigated b y IAi11nc~nann*, who laid especial stress on starting with p u r e acetone. According to his investigations the boiliiig points of isopropyl alcohol and its three distinct hydrates, 3 C,I€,O:,+ '7 H20, 2 C,H,Ci,-+-H,O, aiid 3 C,H,O,+H,O, are s3-S4", TS-SO", 80" and S 1 ' respectively. As these low alcoliols absorb water, complete deliydration is rendered difficult ; aiid as furthermore the boiling point of ethyl alcohol rises in the presence of mater, it will be easily understood that a separation by fractional distillation alone must be well nigh impossible, as far as technical analysis is concerned. But a carefnl examination showed the entire absence of this alcohol. From each of the four samples 5 grms. of the fraction 7S-SO" and of intermediate fractions u p to S S O , obtained by special distillations, were taken and subjected to osidatioii. 5 grms. of the alcoholic liquid were dissolved in 45 grms. of mater and a solution of 9.17 grms. of potassium dichromate, 11.90 grms. of sulphuric acid, 46.70 grms. of water, was added, drop by drop. After complete reduction of the chromic acid t h e oxidation product was distilled off. Its. odor was a t once aldehydic and ethereal. T o test for acetone, 5 cc., previously neutralized with caustic soda, were dissolved i n 2 cc. of fifty per cent. alcohol and a drop of 10 per cent. caustic soda solution and a drop of pure benzaldehyde were added. After two days' standing there was no sign of t h e characteristic dibenzylidene acetone crystals, whilst a blank test with only 0.5 cc. of acetone yielded a n abundant crop. Forther tests with a n alkaline sublimate solution gave likewise negative results. To a mixture of 1cc. of HgCI, solution (190 of water) and 4 cc. of alcoholic potash ( 1 : l O ) 1 cc. of the liquid was added, and the whole was thoroughly shaken. Ammon*Ann. 136 (1865), 37.
ON THE ALCOHOLS OF F C S E L OIL.
57
ium sulphide failed to produce a precipitate in the filtered solution. Whenever alkali was added, the liquid turned first yellow, then reddish brown, and a pronounced smell of cinnanion was discernable, showing the presence of aldehyde. Ammoniacal silver solution was readily reduced. The odor of ethyl acetate could also be detected. Rabnteau" found no less than 150 cc. of i-propyl alcohol, boiling a t 85", in one litre of potato fusel oil of Swedish origin. Nothing further has been published on the subject, the communication in the Bzclletiib d e k c Socie'ti C?ziiniqzie 33 (1880), 178, being nothing but an abstract from the original iu the Comptes Rendus. The alcohol was identified by ultimate analysis, by its conversion into acetone and by its acetate boiling a t 76". Now i t is ethyl acetate that boils a t 76", whilst the isopropyl ether boils a t 90" according to Berthelott and at 90-93" according to Friedel.$ Rabuteau's figure may be simply an error, as 106.9' instead of 116.9" for n-butyl alcohol in the same article is. It is interesting to recall the fact that the very existence of n-propyl alcohol, and as a natural consequence its presence in fusel oil, was considered doubtful as late as 1868 by Mendelejeff.II He separated from 37 grms. of Chancel's$ alcohol 8 grms. of water, 25 grnis. of ethyl and 1grm. of amyl alcohol. The presence of the normal alcohol in fusel oil, not only in that from the marc of grapes, was placed beyond a doubt by there searches of Pierre and Puchot**and of Kraemer and Pinner-tt T h a t Perrotlfdid not succeed in finding it in potato and beet fusel oils was due t o his faulty method. From 60 litres he did not isolate enough of its iodide to be conT-inced of its presence. Without having recourse to dehydration, he separated a fraction boiling n t 95", treated it with desiccating "1. c. tl. c. $1.. c. BZeitschrift fur Chem., 1868, p, 25. SCompt. Rend. 37 (1853), 410. **Ann. Chem. phys. [4] 22 (1868). 234. ttBer. 2 (1869), 401 and 3 (1870), 75. StCompt. Rend. 45 (1857), 309.
subst,ances n i i t l converted it ;it 01ice i n t o tlie iodides. Tssel d r Schepper* proceetled siniilarly with rycb fusel oil. H e freed a frwtion liaising oi-er hetweeii 93 :\ird FJS' from water by agitation with nnliylrous sodium cttrbonate. T h e liquid thus treated distilitd :it S 3 4 4 . tlie mixture of iodides derived from it ;it 72-91 . l'irre ;ind l'nclieot sa\- of the latter, t h a t according t o their exteniteil iii~.estig;itious such mixture was liable to contain tlie iodides of tlie nliole series of alcohols. Yssel de Schepper remarks tlitit his experirneiits make the presence of :til nlcoliol of the 1)ropxlic series in ryc fusel oil very probable. I'icrre m d l'ucliot. vlio esperimeiited with very large qii:intities 04 fusel oils from various wiirces, with the'facilities of a large rlistillery a n d with i m p r o n d a p p r n t u s specially desigiied by them, found 110 i-prop!-i alcoliol. A frnc.tioii of tlie boiling poiut S5-8Gc \vns a t first tlionglit t o be the iso alcoliol, but after tre:itment with potassium carlmnate it was easily furtlier separated h y distillation. ihbutelin, lioivever, was carofiil to free tlic imide fusel oil f r o m water. I
