THE PREPARATION AND MELTING POINTS OF THE · melting point,s might have suffered from a lack of uniformity. ,4nd yet the rate of heating undoubt,edly determines the tem- perature

THE PREPARATION AND MELTING POINTS OF THE HIGHER ALIPHATIC HYDROCARBONS.

BY P. A. LEVENE, c. J. WEST, AND J. V.4N DER SCHEER.

(From the Laboratories of The Rockefeller Institute for Medical Research.)

(Received for publication, February 2, 1915.)

The higher hydrocarbons are of interest to the chemist not only for their practical and theoretical features, but also for their bearing on the identification of fat.ty acids. The number of carbon atoms in the higher fatty acids can not be recognized by direct analysis. The differences in their carbon and hydrogen contents is practically within the limits of error of the analytical methods. Also, the molecular weight est,imation alone was fre- quently found insufficient to permit a definit’e opinion as to the size of the molecule of a fatty acid.

Under such circumstances one naturally formed conclusions on the basis of the physical constants of the acid and of its deriva- tives. And in this connection it was often found convenient to reduce a fatty acid to the corresponding hydrocarbon, which could be then compared with one of the known hydrocarbons.

In the course of our work on the structure of the naturally occurring fatty acids, of as yet undetermined structure, we felt that a revision of the accepted melting points of the higher hydrocarbons was much desired for two principal reasons. First, the older methods of preparation of some of them did not offer suf- ficient assurance of their purity: they were obtained either by vigorous reduction directly from fatty acids or ketones (Krafft,), or by fractionation of naturally occurring mixtures (Mabery). Second, a long series of hydrocarbons was seldom prepared by the same worker, and hence the procedure in determining the melting point,s might have suffered from a lack of uniformity. ,4nd yet the rate of heating undoubt,edly determines the temperature of melting of substances which melt at a comparatively low temperature.

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522 Higher Aliphatic Hydrocarbons

The improvement’ in the methods of reduction of the esters of fatty acids has made easy the access to the corresponding alcohols. In their turn these are transformed readily into the corresponding iodides. Finally, the iodides can be reduced very easily by means of zinc and hydrochloric acid to the corresponding hydrocarbons. Thus the hydrocarbon is arrived at through a greater number of operations than was required by the old hydriodic acid process, but every step in the newer process requires comparatively mild treatment.

Tetracosane and the higher paraffins were prepared by the action of magnesium in dry ether on the iodides containing half t’he number of carbon atoms in their molecule, according to the well known reaction :

2 R I+Mg=R-R+MgIz

In determining the melt.ing points great care was taken in guard- ing uniformity of heating. The observations were carried out in a sulphuric acid bath provided with a stirring arrangement, and the rate of heating was six to seven seconds per degree for the terminal 15”. The results of the observation are recorded in

i-

t,he following table. TABLE I.

“C (&,H3.,. . . . 18 C18H3&. . . . . j 28 CnoHtz.. . . .I 37 CzH46.. . . .~ 44 C,,Hs,,. . . . . . . . . 51 C26Hjq.t. . . . 58 CzsHss.. . . . . . . 60 Cz,,Hm.. . . . . -

C&H66. . . . 70 CagHw,. . . . . . -

C&H,,. -

65.2-65.5 70.5 73.2

I.

I ‘C 20 28 38 47 54

59-60 64-65 69-70

74-74.5 76-76.5

76, 76.5 1 78.5

We have also determined the melting points of the higher hydrocarbons obtained by the reduction of lignoceric alcohol (from lignoceric acid), of ceryl alcohol, and of melissyl (myricyl) alcohol.

1 L. Bouveault and G. Blanc: Compt. rend. Acad. d. SC., cxxxvi, p. 1676, 1903; cxxxvii, p. 60, 1903.


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P. A. Levene, C. J. West, and J. van der Scheer 523

The significance of t,hese melting points will be discussed lat.er when more information on the structure of their mot.her substances has been obtained.

EXPERIMENTAL.

Hexadecane, C16H34

A sample of hexadecane was first prepared by reducing Kahl- baum’s cetyl iodide. Suspended in glacial acetic acid, it was treated with a large amount of zinc dust and warmed on the water bath for two days; dry hydrochloric was occasionally passed into the reaction mixture to hasten the reaction. This preparation, when cooled, filtered, and dried in ethereal solution, boiled over a wide range of temperature, and when fractionated, gave prod- ucts which melted at from 16” t’o 19”.

We then fractionated the cetyl iodide (two different prepara- tions) and found, to our surprise, that this showed a similar range in its boiling point. An attempt to separate t’his into fractions and to reduce the various fractions did not give a ‘satisfac- tory product.

Finally, cetyl alcohol was prepared by the reduction of ethyl palmitate with sodium and absolute et.hyl alcohol’ and this converted into the iodide by heating with molecular proportions of red phosphorus and iodine. Such a sample boiled constantly at 152” under 0.6 mm. pressure.

0.1665 gm. of substance gave 0.1110 gm. AgI (Carius). Calculated for

CnHaaI: Found: I . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36.08 36.04

Reduced as above a hydrocarbon was obtained which boiled at 110” and 1 mm., and melted at 20’. The melting point given in the lit,erature is 17”,2 18”,3 and 19-20°.4

0.0870 gm. of substance gave 0.2711 gm. CO* and 0.1170 gm. HzO. Calculated for

CtsHar: Found: C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84.85 85.01 H............................................. 15.15 15.01

2 E. Eichler: Ber. d. deutsch. them. Gesellsch., xii, p. 1882, 1879. 3 F. Krafft: ibid., xv, p. 1702, 1882. 4 B. Lachowicz: Ann. d. Chem., ccxx, p. 181, 1883.


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Octadecane, CL8HS8

In t.he first attempts to prepare octadecane we tried to reduce a-hydroxystearic acid with hydriodic acid and red phosphorus, using the procedure previously described for the reduction of cere- bronic acid.5 The hydrocarbon was undoubtedly formed in the reaction, but it was almost impossible to obtain it in a pure state.

We then thought to reduce octadecyl alcohol. The alcohol, obtained by the reduction of ethyl stearate, melted at 58.5” and boiled at 210” under 15 mm. pressure. It is best recrystallized from dry acetone. 5 grams of this alcohol, 2 grams of red phosphorus, and 15 cc. of hydriodic acid (density 1.96) were heated in a sealed tube for eight hours at 140”. The product after removal of the excess acid with water and of the iodine by treatment with sodium thiosulphate in ether solution, boiled at 224” under 2 mm. pressure. Analysis showed it to be a mixture of a little hydrocarbon with much octadecyl iodide.

0.1734.gm. of substance gave 0.1012 gm. AgI (Carius). Calculated for

CnHs~1: Found: I . . . . . . * . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33.41 31.54

The pure iodide was obtained by heating 25 grams of alcohol, 12 grams of iodine, and 2 grams of red phosphorus for one hour at 180”. Recrystallized from acetone it melted at 34” and boiled at 169-170” at 0.5 mm. pressure.

0.1868 gm. of substance gave 0.1140 gm. AgI (Carius). Calculated. Found:

I............................................. 33.40 33 .oo

Octadecane was prepared from the impure or pure iodide by reducing with zinc dust and hydrochloric acid in glacial acetic solution. The solid which separated out on cooling was filtered off and the mother liquor concentrated to dryness. Both prod- ucts were taken up in ether, the solution was washed with water and, after drying, distilled in vacuum. The hydrocarbon boiled at 177” under 15 mm. pressure and melted at 28”. This is the melting point reported by Krafft,6 who obtained it by the action

j P. A. Levene and C. J. West: this Journal, xiv, p. 257, 1913. 6 Krafft: Bw. d. deutsch. chem. Gesellsch., xv, p. 1703, 1882; xix, p. 2221,

1586.


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of sodium upon nonyl iodide and by reducing stearic acid with hydriodic acid at 240”.

0.1300 gm. of substance gave 0.3731 gm. CO, and 0.1619 gm. H,O. Ca!culated for

CksHzs: Found: c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84.94 54.80 H . . . . . . . . . . . . . . . . . . . . . . . . . . . . ,............._.. 15.06 15.10

E’icosane, C&H,

Preparation of arachidic acid. After unsuccessful attempts to isolate analytically pure arachidic acid from the mixture of fatty acids obtained by the hydrolysis of peanut oi1,7 we prepared it by the fusion of erucic acid wit,h alkali.8 Best results were obtained by fusion of lots of 10 grams.

10 grams of erucic acid and 5 grams of solid potassium hydroxide were heated in a nickel dish, with or without the addition of a few drops of water until the soap was formed. 15 grams of potassium hydroxide were then added and the heating was care- fully continued until the mass was molten. When further heated the mass again becomes solid, darkens very much, and finally chars and even takes fire. The reaction takes place apparently at this final stage’of the heating. If the heating is stopped when the mass is a dark brown and the acid isolated, a product is obtained which melts at 65-66”, and is not changed by recrystallization from alcohol or acetone. This was not analyzed, but it is probably brassic acid, an isomer of erucic acid. The black reaction product was dissolved in water, the solution acidified and warmed until the fatty acids were molten, then cooled and filtered. The fatty acids were dissolved in a little alcohol, the solution was filtered and cooled. After two or three recrystallizations a pure arachidic acid was obtained, melting at 77”. In order to insure t#he complete removal of any unsat,urated acids, the product from the

? Compare H. Meyer, L. Brod, and W. Soyka: Monatsh. f. Chem., xxxiv, p. 1113, 1913. We have been able, however, to obtain fair yields of pure lignoceric acid, melting at S&81”, by fractionating the more insoluble fractions

8 R. Willstatter, E. W. Mayer, and E. Huni (Ann. d. Chem., ccclxxviii, p. 73, 1911) mention that they have used this method of preparation, but give no details. Because of the trouble of finding the best conditions for this fusion Tve have given rather full details.


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first crystallization out of alcohol was changed into the lead salt, this twice recrystallized out of toluene at room temperature and the lead salt decomposed as usual with hydrogen sulphide.

Twice recrystallized out of toluene at room temperature the acid melted sharply at 77”.

1.000 gm. of acid, dissolved in a mixture of benzene and methyl alcohol required 31.9 cc. & HCl for neutralization.

Calculated for CmH1o0-x Found:

Mol. wt.. . . . . . . . . . . . . . . . . . . . 312.3 313.1

Eicosyl alcohol. Ethyl arachidate was reduced with sodium and amyl alcohol and the mixture of soap and alcohol worked up in the usual manner. 90 grams of ester gave 35 grams of alcohol, which boiled at 210” and 0.3 mm. pressure and melted at 66-67”, after recrystallization from dry acetone. The melting point given by Haller,g who first prepared it in the same way, is 71”, while WillstSitter1o gives 63-64”.

Eicosyl iodide. 15 grams of eicosyl alcohol, 11.5 grams of iodine, and 1.5 grams of red phosphorus were heated in a met.al bath at 180” for one hour and twenty-five minutes. The reaction product was taken up in ether, purified with sodium thiosulphate, and distilled. It boiled at 192” under 0.5 mm. pressure and melted at 42”, after recrystallization from dry acetone.

0.1847 gm. of substance gave 0.1048 gm. AgI (Carius).

Calculated for CmHaI: Found:

I . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31.01 30.67

Eicosane was prepared in the usual manner by reducing eicosyl iodide with zinc dust and hydrochloric acid. It boils at 148” at 0.6 mm. pressure and melts at 38”. Krafft’l gives the melting point as 36.7”.

Q A. Haller: Compt. rend. Acad. d. SC., cxliv, p. 594, 1907. 10 Willstatter, Mayer, and Huni: kc. cit. I1 Krafft: Ber. d. deutsch. them. Gesellsch., xv, p. 1717, 1882; xix, p.

2220, 1886.


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0.1037 gm. of substance gave 0.3228 gm. COZ and 0.1406 gm. HsO.

ca1culaa; for

85.0; Found:

c ., ,.., ,., ,.. 84.02 H . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18.00 15.14

We first attempted to prepare the necessary docosyl alcohol by the reduction of erucyl alcohol. This was obtained by the reduction of ethyl erucate with sodium and amyl alcohol. Diffi- culty was found in the extraction of the mixture of soap and alcohol with ether or petroleum ether, since some of the soap always went into solution and did not separate again upon drying the solution at 0”. This soap prevented further purification because in the distillation it caused violent foaming. The best results were obtained by the use of dry acetone. The erucyl alcohol thus obtained boiled at 1999200” at 0.2 mm. pressure and melted at 31-32.” Recrystallized from a little acetone, it melted at, 33- 34”, while Willstatter gives 34-35” after recrystallization from methyl alcohol at -30”.

Difficulty was again encountered in an attempt to reduce the alcohol with hydrogen, using colloidal palladium as a catalyzer, little or no hydrogen being absorbed by a solution of the alcohol in ethyl alcohol, amyl alcohol, ether, or acetone. This may be due to the presence of slight traces of ash. In methyl alcoholic solution about 50 per cent was reduced, though the method was hardly suitable for preparative purposes. The docosyl alcohol was separated from unchanged erucyl alcohol by crystallization from acetone and from chloroform. It melted at 73-74”. Willstatter gives 71-71.5”; Meyer, 71”.

For the preparation of a larger quantity of docosyl alcohol we reduced erucic acid to behenic acid by the palladium hydrogen method; the acid melted at 84” after one recrystallization from acetone. We never had the difficulty mentioned by Meyer of obtaining a product with a low melting point. This was esteri- fied and reduced with sodium and amyl alcohol. Recrystallized out of acetone and then from chloroform it, melted at 73-74”.


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0.1050 gm. of substance gave 0.3111 gm. CO2 and 0.13U gm. &O. calclll:tted for

Cz2IId): I:ourrd. c.. . * 80.88 80.80

II............................................. 14.22 14 .a0

Docosyl iodide was prepared by heating 15 $rarns of docosyl alcohol, 6 grams of iodine, and 2 grams of red phosphorus for one hour at 180”. Recrystallized from absolute ether it melted at 49”. Meyer, Brod, and Soyka give 46”.

0.1934 gm. of substance gave 0.1025 gm. AgT (Carius). Cdculxtctl for

chH451: Found: I . . . . . . . ..___..__.__..___..........._.......... 29.1 28.7

Docosane. Docosyl iodide was converted into the hydrocarbon by the usual method. The product. was distilled in vacuum and then recrystallized several times from dry acetone and finally from absolute ether. Docosane melts &t 47”. Krafft12 gives the melting point as 44.4”.

0.0990 gm. of substance gave 0.1300 gm. Hz0 and 0.3086 gm. COY. Cnlcilinted for

CnH46: F0Lil2d: c............................................. 85.05 85.02 H .._. ._._.., .._. .__, ,__, ,_.. .._... 14.94 11.70

Tetracosane, C&,H,,

The preparation and properties of this hydrocarbon, as well as the isomeric hydrocarbon obtained from lignoceric acid have been described in an earlier article.13 The normal hydrocarbon melts at 54”, the iso hydrocarbon at 51”. The name liynocerane is sug- gested for this iso compound until the constitution of the lignoceric acid is definitely established.

Hexacosane, CZ6Hs1

Tridecyl alcohoP4 was obtained by reducing ethyl tridecylate with sodium and absolute ethyl alcohol. It boils at 117” at 0.5 mm. pressure.

Tridecyl iodide was prepared by heating 25 grams of alcohol, lc.5 grams of iodine, and 3 grams of red phosphorus for one hour

I2 Krafft: ibid., xv, p. 1718, 1882. I3 Levene and West : this Journal, xviii, p. 477, 1911 I4 J. ISlau: Monntsh. j”. Chenz., xxvi! p. 103, 1905.


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at 180”. Purified with sodium thiosulphate it was obtained as a colorless oil, boiling at 117” and 0.5 mm. pressure.

0.1794 gm. of substance gave 0.1350 gm. AgI (Carius). Calcul2ltte~l for

CnIl2,I: lbund: I......,......,,.......................,...... 40.39 40.69

Hexucosane was prepared by the action of 0.9 gram of magnesium upon 10 grams of tridecyl iodide in 150 cc. of absolute ether (freshly dried over sodium). The reaction proceeds slowly and is complete after boiling gently for five or six hours. Upon cooling the reaction mixture the hydrocarbon separates out. The product was brought into solution by adding more ct,her and warm- ing, the residue of the magnesium filtered off, the solution treated with dilute hydrochloric acid, washed free of acid with water, and the hydrocarbon crystallized out of the concentrated solution. This was distilled in vacuum 00 remove traces of ash, the substance boiling at 199” and 0.4 mm. pressure. Twice recrystallized out of ether ‘it formed glistening scales which melted at 59-60”. Maberyl” isolated a hydrocarbon from petroleum having this composition and melting at fj8”.

0.0944 gm. of substance gave 0.2946 gm. CO2 and 0.1234 gm. 11~0. Calrulnt,ed for

CzaH;a: Found:

c............................................. 85.17 85.12 H............................................. 14.83 14.63

Octacosane, C&H,,

Tetradecyl iodide was prepared according to Majima and Nakamura.‘” It boiled at 128” under a pressure of 0.5 mm.

0.1750 gm. of substance gave 0.1262 gm. AgI (Carius). Ca!culatcd for

CwHd: E‘i~ull<l: I............................................. 39.17 38.99

The action of magnesium upon an ether solution of t,etradecyl iodide, gave octacosane, glistening leaflet’s from absolute ether, boiling at 224” under 1.1 mm. pressure, and mehing at 64-65”. Maberyl” gives 60” as the melting point of t,hc product isolated from petroleum.

IS C. F. Mabery: Am. Chem. Jour., xxviii, pp. 193, 195, 1902. “j R. Majirna and I. Nakamurn: Ber. d. deutsch. them. Gesekh., xlvi,

p. 4094, 1913.


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0.0968 gm. of substance gave 0.3026 gm. CO? and 0.1266 gm. HzO. Calculated for

C~sHsa: Found :

c... . . . . . . . . . . . . . . . 85.17 85.25 H . ..__., . . . . . . . . . . . . . . . . . . . . . . . . . . 14.82 14.63

This hydrocarbon has recently been prepared by Gascard,17 through the action of sodium upon pentadecyl iodide in boiling xylene for ten hours.

Pentadecyl iodide, prepared from the alcohol with iodine and red phosphorus, boiled at 138-139” under 0.5 mm. pressure.

0.1763 gm. of substance gave 0.1220 gm. BgI (Cariua). Calculnted for

CxHa,J: Found: I............................................. 37.78 37.43

Magnesium, acting upon this iodide in ethereal solution, forms triacontane, which separated from the reaction mixture as glistening scales. These boiled at 235” under a pressure of 1 mm. and melted at 69-70”. Gascard gives 65.2-65.5”.

0.1015 gm. of substance gave 0.3169 gm. CO2 and 0.1331 gm. H20. Calculated for

GOHW:. Found :

c............................................. 85.21 a.22 II.. . . . . . . . . . . 14.79 14.68

Dotriacontane, C32H66

Besides the older work on this hydrocarbon, it has recent13 been obtained by Rutta@ as a by-product in the preparat,ion of margaric acid by the action of magnesium upon cetyl iodide, followed by the action of carbon dioxide, and by Gascard,lY who prepared it by the action of sodium amalgam upon dotriacon- tanyl iodide (the dotriacont.anol was isolated as an ester from gum lac). Both aut.hors give the melting point as 70.5”.

The hydrocarbon has been obtained in a yield of 70 to 80 per cent by the action of magnesium upon cetyl iodide in absolut,e

l7 A. Gascard: Compt. rend. Acad. d. SC., cliii, p. 1484, 1911. l8R. F. Ruttan: VIIIth International Congress oJ Applied Chemistry,

xxv, p. 435, 1912; Chem. Abstr., vii, p. 2190, 1913. 19 Gascard: Compt. rend. Acad. cl. SC., clix, p. 258. 1914.


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ether (moisture was not as rigorously excluded as in the case of Ruttan), Recrystallized from ether dotriacontane forms large lus- trous plates or scales, boiling at 245’ at 1.5 mm. pressure and m&ing at 74-75”.

0.1030 gm. of substance gave 0.3218 gm. CO, and 0.1358 gm. HzO. Ca!culated for

CazHss: Found : C............................................. 85.24 85.21 II.. 14.76 14.76

l’etratriacontane, CsdHi0

Heptadecyl alcoholzO was prepared by reducing ethyl margarate with sodium and amyl alcohol. Recrystallized from acetone it melted at 54”. The corresponding iodide boiled at 158-159” under 0.5 mm. pressure. 13 grams of iodide in 150 cc. of absolute ether, treated with 0.9 gram of magnesium, and boiled gently for six hpurs, gave tetratriacontane, glist’ening scales or leaflets from absolute ether, boiling at 255” and 1 mm. pressure and melting at 76-76.5”. Gascard gives the melting point as 73.2”.

0.1034 gm. of substance gave 0.3230 gm. CO2 a,nd 0.1356 gm. HzO. C&ulated for

CarHio: Found: C . . . . . . . . . . . . ..__........_...t.............. X5.26 85.21 H., _. _. 14.74 14.76

Hexatriacontane, CsBHil

Hexatriac0ntan.e is readily obtained by the action of magnesium upon an ethereal solution of octadecyl iodide. Twice recrystallized from petroleum ether (boiling point 60670”) it forms lus- trous leaflets and scales, boiling at 265” under 1 mm. pressure and melting at 78.5”. This hydrocarbon has previously been prepared by Gascard, through the action of sodium in a boiling xylene solution of octadecyl iodide for ten hours, and by Oskeckzl who obtained it as a by-product in the preparation of nondecylic acid by the action of carbon dioxide upon octadecyl magnesium bro- mide. Contrary to Oskeck, who states that it is not volatile without decomposition in vacuum, we had no difficulty in distill-

*O Gascard: ibid., cliii, p. 1484, 1911. )’ Oskeck: Jour. RIL.SS. Phyn. Chenk. Sot., xlvi, pp. 416-7; Chem. Abstr.,

viii, p. 3185, 1914.


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ing it in a vacuum of 1 mm. These authors give the melting point as 76” and 76.5”.

0.1012 gm. of substance gave 0.3160 gm. COS and 0.1332 gm. HZO. Calculated for

chII71: F’ound: c............................................. 85.27 85.25 II............................................. 14.73 14.74

Iso-hexacosane, cerane, CZ6Hjq

Ceryl alcohol was obtained by the hydrolysis of Chinese wax, using the following procedure: 100 grams of wax were dissolved in 500 cc. of hot toluene, 750 cc. of normal alcoholic potassium hydroxide were added, and the mixture was heated to boiling for six hours; the toluene was removed by distillation with steam, the residue poured into two liters of saturated salt solution, and the precipitate of salts and alcohols filtered off and dried in the air. This mixture was then thoroughly extracted with gasoline boiling between 70” and 80”. The precipitate which forms from the gasoline is recrystallized from gasoline and then from acetone. The yield was about 25 grams, depending upon the thoroughness of the extraction. The alcohol melt)ed at 80” and solidified at 70°.

0.101% gm. of substance gave 0.3020 gm. CO2 and 0.1252 gm. &O. Calculsted for

CPEHNO: Found : c............................................. 81.59 81.42 H............................................. 14.23 13.87

The acetate, prepared by boiling the alcohol with acetic anhydride for two hours and recrystallized from dry acetone, melts at 64-65”. Benedict and UlzeP’ give 65”.

Ceryl iodide was obtained by heating 25 grams of alcohol, 5 grams of red phosphorus, and 9 grams of iodine for two hours at 180”. Recrystallized from acetone it melted at 56-57” and solidified at .56-55”. Ryan and AlgarE3 give the melting point a.t 55-56”.

0.1708 gm. of subst,ance gave 0.0800 gm. AgI (Carius). Calculated for

ChHd: Foucd : I............................................. 25.80 25.33

z R. Benedict and F. Ulzer: Monatsh. f. Chews., ix, p. 581, 1888. !a H. Ryan and J. Algar: Proc. IZoy. Irish Acad., xxx, p. 97, 1916;

Chem. Abstr., vii, p. 3318, 1913.


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I’. A. Levene, C. J. West, and J. van der Sheer 533

The hydrocarbon, cerane, was obtained by reducing the iodide with zinc dust and hydrochloric acid in glacial acetic acid for two days. Recrystallized from absolute ether it forms glistening scales, which boil at 207” under 0.7 mm. pressure and melt at 61”. Since this is higher t,han the corresponding normal hexacosane, it, is probable that ceryl alcohol and cerotic acid which are obtained by heating the alcohol with soda lime have a branched and not a normal carbon chain. Nafzgerz4 obtained a hydrocarbon by the distillation of ethyl cerotate under ordinary pressure, to which he ascribed the formula C2,jH54. Since this melted at 44”, it is evident that either the hydrocarbon was very impure, or that it was some other decomposition product of the acid.

0.1026 gm. of substance gnvc 0.3202 gm. COZ and 0.1346 gm. H20. Calculated for

CmHsr: Pound : c............................................. 85.15 85.12 H ._. ._. ._. ._. ._. .__._. .__. 14.85 14.68

lso-tr~iacwzhne, melissane, C30H,Z

Melissyl alcohol was obtained by the hydrolysis of carnauba wax in practically the same way as described above for ceryl alcohol; the hydrolysis was carried out in alcoholic-xylene solution. The precipitate of alcohol obtained from the gasoline was recrystallized from a large volume of dry acetone. Melissyl alcohol thus prepared has a melting point of 87.5-88” and solidifies at 87”. The melting point of the alcohol has been variously ‘given as 85” by Brodie25 and Pieverling,26 85.5-85.7” by Sttircke,27 by Schwalb,2s and by Benedict and Ulzer,2g and 88” by Gascard3” and by Matthes and Sander.31 In this way 55 to 60 grams of pure alcohol may be easily obtained from 200 grams of carnauba W&X.

44 F. Nafxger: Ann. d. Chern., ccxxiv, p. 236, 1884. p5 13. C. Brodic: i&id., lxxi, p. 147, 1849. 46 L. von Pieverling: ibid., clxxxiii, p. 346, 187G. fi H. Stiircke: ibid., ccxxiii, p. 292, 1884. ?* F. Schwalb: ibid., ccxxxv, p. 126, 1886. 38 Benedict and Ulzer: Zoc. cit. 3o Gascard: Jaw. de Pharm. et de Chim., series 5, xxviii, p. 49, 1893. 31 H. Matthes and H. Sander: Arch. d. Pharm., ccxlvi, p. 168, 1908.


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0.1014 gm. of substance gave 0.3050 gm. (10~ and 0.1274 gm. HzO. Calculated for

CsoHszO: Fourid: c............................................. 82.10 82.08 H............................................. 14.25 14.08

The acetate was prepared by boiling 2 grams of alcohol with 25 cc. of acetic anhydride for four hours. Recrystallized from dry acetone it melted at 74-75”. Benedict and Ulzer give its melting point as 70”, Gascards as 73”, and Matthes and Sander as 75”.

0.1016 gm. of substance gave 0.2972 gm. CO, and 0.1208 gm. H20. Calculuted for

c32&401: FlXd: C . . . . . . . . . .._ _. _. _. _. 79.93 79.93 I-I............................................. 13.4% 13.29

The iodide was prepared from 25 grams of alcohol, 8 grams of iodine, and 5 grams of red phosphorus by the usual method. The cooled reaction product was extracted with dry acetone, filtered hot from the excess of phosphorus, and recrystallized from dry acetone. It melted at 70-71” and solidified at 69.5”. Piever- ling gives 69.5” as its melting point.

0.1902 gm. of substance gave 0.0816 gm. AgI (Carius). Calculated for

ChIhI: Found:

I . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23.14 23.20

The hydrocarbon, nwlissane, was prepared by reducing the iodide with zinc and hydrochloric acid. Recrystallized from gasoline (boiling at 70-80”), it formed glistening scales and leaflets, which melted at 73-74”, and distilled at 222” under 0.3 mm. pressure. This melting point would likewise indicate a branch carbon chain for melissyl alcohol and melissic acid.

O.OQ68 gm. of substance gave 0.3025 gm. COT and 0.1272 gm. HtO. Cslculated for

CmHm: Found: C’............................................. 85.21 85.22 II............................................. 14 79 14.70

_.-------__- ~~~~~

32 Gascard: Uull. ?~Jc. chim., series 3, xi, p. 186, 1894.


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P. A. Levene, C. J. West and J. van der ScheerHYDROCARBONS

POINTS OF THE HIGHER ALIPHATIC THE PREPARATION AND MELTING

1915, 20:521-534.J. Biol. Chem.

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THE PREPARATION AND MELTING POINTS OF THE · melting point,s might have suffered from a lack of uniformity. ,4nd yet the rate of heating undoubt,edly determines the tem- perature