Art. XXIX.—Montan Wax.
Communicated by Professor Easterfield.
[Read before the Wellington Philosophical Society, 4th October, 1911.]
Montan wax is a hard yellowish material which, on account of its high melting-point, is used for raising the melting-point of stearine candles, and, on account of its low price, has also found some use as an adulterant of beeswax. The wax was first manufactured from the brown coal of Saxony and Thuringia, and more recently has been prepared from Irish lignites.
In the manufacture of montan wax, pyropissite is either extracted with light petroleum and the soluble bitumen, obtained from the extract, then distilled in superheated steam, the distillation being repeated until a nearly colourless product is obtained, or the brown coal is itself distilled with superheated steam.
The method of manufacture was first patented by E. von Boyen (German patent 101373, 1st July, 1897). In the original patent E. von Boyen* described the wax as consisting of two well-characterized substances—an acid and an unsaturated hydrocarbon. C. Hell† assigned the formula C29H58O2 to the above-mentioned acid, now called “montanic acid.”
E. von Boyen‡ adopted the formula C29H58O2 for the acid, but now stated that the other constituent is an alcohol melting at 60°, which is readily attacked by sulphuric and nitric acids. He regarded the original bitumen as an ester of montanic acid which is decomposed during distillation.
K. Eisenreich§ purified montanic acid by fractional precipitation with magnesium acetate. He adopted the same formula for the acid as von Boyen and Hell. He noted that the last portions of the acid to be precipitated melted several degrees lower than the earlier fractions, but no attempts were made to obtain acids of lower molecular weight from these fractions.
To the non-acid constituent of the wax, melting at 63°5°, he assigned the formula C42H86O, and supported the formula by an ebullioscopic molecular-weight determination, but could not find any evidence that the substance was an alcohol.∥
[Footnote] * Chem. Central Blatt, 1899, vol. 1, p. 864.
[Footnote] † Zeit. f. Angew. Chem., 1900, p. 556.
[Footnote] ‡ Chem. Central Blatt, 1901, vol. 2, p. 1285.
[Footnote] § Journ. Soc. Chem. Ind., 1909, p. 991.
[Footnote] ∥ Such a formula, CnH2n+2O, can only represent an alcohol or an ether derived from a higher alcohol; but the low melting-point of the substance (63°5°) makes it extremely improbable that the compound is anything else than a hydrocarbon.
Ryan and Dillon* gave the formula for montanic acid as C28H56O2. The non-saponifiable portion they found to melt at 58–59°, and the analysis gave 2°5 per cent. of oxygen, which agrees approximately with the formula C42H86O of Eisenreich. They also stated that no primary or secondary alcoholic group is present in the substance.
The work of previous observers may therefore be summed up as follows: (a.) Three investigators have assigned to montanic acid the formula C29H58O2, while one investigator has assigned the formula C28H56O2, to the same acid; (b.) von Boyen first stated that the non-acid constituent was an unsaturated hydrocarbon, afterwards that it was an alcohol. Eisenreich and also Ryan and Dillon state that the non-acid constituent is not alcoholic in nature, but regard it as an oxygenated compound.
In the present paper it is shown that: (1) the “montanic acid” occurring in the wax is in reality a mixture of three acids—cerotic (C26H52O2), montanic (C28H56O2), and melissic (C30H60O2) acids; (2) the non-saponifiable portion is an olefinic hydrocarbon, probably C28H56 or C26H52, both of which, being olefines, would have, of course, the same percentage composition.
Cerotic and melissic acids were described by Brodie† as constituents of beeswax, but have not hitherto been found in any mineral substance. The separation of these acids was tedious, involving a series of over forty fractional precipitations by magnesium acetate, whereby the cerotic and melissic acids were obtained in a state of purity.
Montanic acid, the acid of intermediate molecular weight, was isolated by conversion of the crude acid into its ethyl salt, and subsequent distillation under reduced pressure. Some fifteen fractionations were needed before the substance could be considered pure.
After purification, the cerotic and montanic acids both crystallized in pearly scales. Hitherto cerotic and montanic acids have been described as crystallizing in needles; and the crude acids certainly do so, but the pure acids crystallize in scales, and in so doing resemble all the lower members of the higher fatty acids which have been obtained in a state of purity.
There can be little doubt that cerotic, montanic, and melissic acids belong to the homologous series of the higher fatty acids, and that these acids are all normal fatty acids. A comparison of the physical properties of a number of their derivatives supports this (Tables I-III, p. 285). In the case of montanic acid it has been possible to show that the substance is undoubtedly normal heptacosane carboxylic acid.
The occurrence of montan wax as the principal product of steam distillation of bituminous coal is of great interest. Krämer and Spilker‡ have shown that fats and waxes, if distilled under pressure, yield mixtures of hydrocarbons not unlike many natural petroleums, and they have suggested that some petroleums at least owe their origin to the decomposition of wax derived from algae.
At first it appears difficult to imagine such supplies of wax in nature as, by decomposition, would give rise to the immense quantities of oil present in the large oilfields. Brown coal is, however, even more widely distributed
[Footnote] * Sci. Proc. Roy. Dub. Soc., vol. 12, p. 20, 1909.
[Footnote] † Phil. Trans. Roy. Soc., 1848.
[Footnote] ‡ Berichte, vol. 32, 1899, and vol. 35, 1902
than petroleum, so that the suggestion of these authors gains in probability, in that it is known that large quantities of wax, almost certainly derived from micro-organisms, are present in this lignite.
Krämer and Spilker's hypothesis would appear, in this light, much more probable than that of Mendeleef, Moissan, and others, who suggest that the natural petroleums are due to the action of water upon metallic carbides, substances which have never been found in nature in large quantity.
If we assume with von Boyen that the bitumen derived from pyropissite is an ester of montanic acid, then the fact that the inert constituent of the wax derived from the bitumen is an olefinic hydrocarbon, probably C28H56, suggests that the reaction during steam distillation of the wax is represented by the equation
C27H55CO2C28H57 = C27H55CO2H + C28H56
Montanyl montanate = Montanic acid Montanene,*
just as during the distillation of Chinese wax we have—
C25H51CO2C26H53 = C25H51CO2H + C26H52
Ceryl cerotate = Cerotic acid Cerotene.
It is to be hoped that the time is not far distant when a systematic examination of the brown coals and oil-shales of New Zealand will be made, with the object of elucidating the chemical nature of their constituents. It is a regrettable and remarkable fact that, notwithstanding the enormous annual consumption of coal in all countries of the world, we are still practically in ignorance as to the chemical nature of this fuel.
Part I.—The Composition of Montan Wax.
A. The Acid Constituents.
|Wax used by Author.||Eisenreich's Wax.||Ryan and Dillon's Wax.|
|Percentage of montanic acid (if M.W. = 424)||65·0||72·66||53·0|
It will be seen that the three samples of wax melt within 2° of one another, and that the wax used in this research had an acid and saponification value intermediate between those of the other investigators. Slight differences in the rate of distillation of the original material would readily account for these differences in the properties of the wax.
[Footnote] * The fact that the proportion of hydrocarbon in commercial montan wax is much less than that of the free acids is not surprising, for the physical properties of the hydrocarbon are such as to lead to loss during the commercial process of recrystallization from benzene.
[Footnote] † This montan wax was obtained from Schliemann and Co., Hamburg and London.
[Footnote] ‡ Journ. Soc. Chem. Ind., 1909, p. 991.
[Footnote] § Sci. Proc. Roy. Dub. Soc., vol. 12, 1909.
Crude Montanic Acid.
Crude montanic acid was extracted from montan wax by the following process: 500 grams of montan wax were digested five times with hot alcohol, about 3 litres for each extraction. This hot alcoholic solution, containing practically the whole of the free acids, was siphoned off, neutralized with ammonia, and the acids were then precipitated as calcium salts by means of alcoholic calcium-chloride solution. The calcium salts were then filtered off by means of a hot funnel.
The crude calcium salts thus obtained were dried on the water bath, and then pulverized and boiled out six times with alcohol. Motor spirit, although a very good solvent of unsaponifiable matter, could not be employed for the purification of the calcium salts, by reason of the almost unfiltrable paste produced in this case.
The calcium salts were now decomposed by glacial acetic acid, and the crude acid thus obtained melted at 81°5°. Crystallization from motor spirit raised the melting-point to 82°5°, but further crystallization from alcohol, motor spirit, and acetic acid did not further raise the melting-point. The acid crystallized from acetic acid in granules.
The titration of the acid thus obtained, although the greatest care was taken in the standardization of the decinormal solutions employed, gave a molecular weight of 432—i.e., almost the mean of the molecular weights required for the formulae C29H58O2 and C28H56O2.
It thus appeared that either the montanic acid contained some inert compounds such as hydrocarbons or ketones, or that it was admixed with a higher acid. To test the first of these suppositions the acid was purified by potash-lime saponification with an excess of lime, and then extraction with hot motor spirit in which high-molecular-weight hydrocarbons and ketones are readily soluble. The molecular weight of the purified acid, however, remained unchanged (430).
That the acid, although its melting-point was unaltered by further crystallization, was not a single compound was demonstrated by submitting 10 grams of the acid to fractional precipitation with magnesium acetate, for the regenerated acids from the different fractions had the following melting-points:—
|Fraction||I||(weight 1/10 of original acid taken)||85°5°|
|"||II||" 3/10 "||83–84°|
|"||III||" 4/10 "||81–82°|
|"||IV||" 1/10 "||74°5°|
Fractional precipitation was therefore undertaken on a large scale. 50 grams of crude montanic acid were dissolved in 800 c.c. of alcohol, the solution rendered alkaline with ammonia, and then precipitated with 20 c.c. of a solution of magnesium acetate (equivalent to 10 grams montanic acid). Four fractions were thus precipitated, and a fifth fraction was obtained from the alcoholic filtrate on cooling. The regenerated acids from these fractions had the following melting-points:—
This practically agrees with Eisenreich's experience. He obtained the first four fractions melting at 83°. It seems strange that he did not proceed with further fractional precipitation.
Fractions 1 and 2 were each fractionally precipitated again, and it was found that the regenerated acids from the first two precipitates had risen 3° in melting-point.
Fractions which melted within 1° were mixed before the next precipitation was proceeded with. After four consecutive precipitations of the highest melting fraction in each case, there resulted an acid melting at 88°5°. This fraction was not altered in melting-point by a series of further fractional precipitations, and must be regarded as pure melissic acid, which, according to Brodie* and to Schwalb,† melts at 88–89°. It is, however, to be noted that the melissic acid from the oxidation of canaüba wax is stated by Maskelyne‡ to melt at 91°.
The following is a scheme of precipitations employed in the isolation of melissic acid. The melting-points given are those of the regenerated acids:—
Repeated fractional precipitation failed to yield an acid melting at about 83° which could be considered pure, but from fraction 5 precipitation yielded lower fractions, which when repeatedly crystallized melted at
[Footnote] * Phil. Trans. Roy Soc, 1848.
[Footnote] † Annalen, 235, p. 135.
[Footnote] ‡ Journ. Chem. Soc., 1869, vol. 22, p. 87.
78–78°5°, and were absolutely identical with the cerotic acid of beeswax. This identity was proved as follows:—
(a.) Both acids had the same melting-point, and a mixture of the two acids melted within 0°5° of the original acid.
(b.) The ketone prepared from each, by means of the catalytic action of metallic iron, melted at 92°5–93°.
(c.) The ethyl esters of each acid had the same boiling-point, 285°, at 14 mm.
(d.) Both acids crystallized in pearly scales.
Preparation of Pure Montanic Acid.
Although the method of fractional precipitation did not yield montanic acid in a state of purity, yet by fractional distillation of the ethyl ester of the crude acid under diminished pressure purity was at last attained. 100 grams of crude montanic acid were dissolved in 2,300 c.c. of 95-per-cent. alcohol, to which had been added 60 c.c. strong sulphuric acid. The whole was kept hot on the water bath for forty-four hours. It was found that equilibrium was attained within thirty hours, but if 95-per-cent. alcohol is used there still remains 6 per cent. of acid unconverted to ester. The crude ester was therefore reheated with absolute alcohol and a little sulphuric acid in order to complete the esterification, and now gave, after removal of mineral acid, only the slightest trace of free organic acid.
The ester obtained by the above process was carefully washed free from sulphuric acid, then dried in a vacuum over sulphuric acid, and distilled under reduced pressure. The apparatus employed for this purpose was novel, in that the neck of the distilling-flask was electrically heated, and in that a special type of fractionator was used. Three fractions were always collected from each distillation. The following diagram shows at a glance the method of procedure and the number of distillations performed:—
The following table is a comparison of the physical constants of the five final fractions obtained by repeated distillation:—
|No.||Boiling-point.||Melting-point, Ester.||Melting-point, Acid.||Per Cent. Weight of Fraction.||Molecular Weight.||Apparent Formula|
Fractions C8 and C9 were obviously impure, being mixtures of montanic acid and melissic acid, together with some ketone. The free acid derived from these two fractions did not crystallize in plates, and gave titration values much above that required for montanic acid. From the residues, after saponification, a single fractional precipitation gave a regenerated acid, melting at 88°5°, which corresponds with the melting-point of melissic acid.
The acid obtained from the saponification of B11 is to be regarded as pure montanic acid,* for further fractional distillation of the ester did not alter the melting-point of the ester or of the acid obtained from the ester nor did it affect the titration value of the acid thus obtained within the limits of experimental error. Thus, acid from B11: 1°0785 grams reqd.
25°60 c.c. N/10 KOH = M.W. = 421.
Acid from B11 twice redistilled: 1°845 grams reqd.
43°70 c.c. N/10 KOH = M.W. = 427.
The titration values approach very closely to that required for a formula C28H56O2, thus placing montanic acid among the even members of the higher fatty acid series. The montanic acid purified by this process crystallized in plates, and was readily soluble in hot ethyl acetate or motor spirit, and fairly soluble in hot alcohol and acetic acid.
In concluding this section on the acid constituents the writer wishes to summarize the following results:—
(a.) Crude montanic acid is a mixture of cerotic, montanic, and melissic acids.
(b.) Pure montanic acid crystallizes in plates, melts at 83°, and has a molecular weight corresponding to the formula C28H56O2. (Previous experimenters have described it as crystallizing in needles, which is correct so long as the substance is impure.)
(c.) Cerotic acid has also been obtained for the first time in nacreous crystalline plates.
B. The Non-Acid Constituents of Montan Wax.
The alcoholic solution o [ unclear: ] f the crude montan wax from which the acids had been precipitated by calcium chloride contained an almost neutral substance, which was recovered by evaporation of the alcoholic mother
[Footnote] * The acid crystallized in pearly scales, which also is an indication of purity.
liquor. To remove the last traces of acid the substance was melted and stirred into powdered quicklime, which was then slaked by means of a solution of potash. The porous mass thus obtained was extracted with hot motor spirit which on evaporation deposited a crystalline substance which after repeated crystallization melted at 59–60° and was unchanged by further crystallization.
On analysis, this substance gave the following values: 0°1492 grams gave 0°4713 grams CO2 and 0°1882 grams H2O.
|Calc. for CnH2n.||Calc. for C27H56.||Found.|
|C = 85°71||C = 85°26||C = 86°14|
|H = 14°29||H = 14°74||H = 14°01|
The analysis shows that the substance is probably an olefinic hydrocarbon. This was confirmed by its behaviour with bromine water, which was rapidly decolourized when warmed with it. A rough determination of the bromine absorbed was as follows: 0°25 grams hydrocarbon absorbed 0°073 grams bromine.
|Calc. for C28H56Br2.||Found.|
|Br = 29°0 per cent.||Br = 22°6 per cent.|
Note.—Bromination was probably not complete, the reaction being only allowed to proceed for about three hours.
The molecular weight of the hydrocarbon as determined by the ebullio-scopic method pointed to a hydrocarbon of molecular weight 380.
0°64 grams hydrocarbon raised the boiling-point of 8°5 c.c. of anhydrous freshly distilled benzene 0°65°.
Molecular weight = 380. Calc. for C28H56 = 392.
The melting-point (59–60°), the analysis, and the molecular-weight determination all point to a hydrocarbon of the formula C27H54 or C28H56, but it is only by the preparation and analysis of the carefully purified dibrom addition product that we shall ascertain whether the substance contains 26, 27, or 28 atoms of carbon.
Part II.—The Acids of Montan Wax, and Some Compounds Derived From Them.
Since the ultimate aim of this research is to show the connection which exists between cerotic, montanic, and melissic acids, it follows that the physical constants of these acids, their melting-points, their molecular weights, and the properties and physical constants of their compounds should be accurately determined.
The accurate correlation of such data affords no small interest to the chemist, as has been pointed out by Krafft,* Franchimont,† and more recently by P. W. Robertson (“The Melting-points of the Anilides, P. Toluidides, and Naphthalides of the Normal Fatty Acids”).‡ Furthermore, this series of fatty acids and their derivatives presents a group unsurpassed in the whole of organic chemistry for illustrating the principle of homology, and therefore it is desirable that the physical constants of
[Footnote] * Berichte, vol. 15, 1719.
[Footnote] † Rec. Pays., vol. 16, p. 126, 1897.
[Footnote] ‡ Journ. Chem. Soc., 1908, p. 1033.
all the members of the series from the highest to the lowest should be accurately determined and correlated. Moreover, it is desirable that the proof of the constitution of the higher members of the series should be demonstrated with as absolute rigidity as has been the case with the lower acids from acetic to arachidic.
A. Cerotic Acid and its Derivatives.
Since cerotic acid may be obtained from montan wax only after a very tedious and laborious process, and since the cerotic acid of beeswax has been shown to be identical with that prepared from montan wax, beeswax was therefore used for the preparation of cerotic acid in large quantity.
The beeswax employed for the isolation of cerotic acid was New Zealand unbleached wax, which was obtained from a business firm dealing in large quantities of the natural product, and was guaranteed by them to be pure unadulterated New Zealand beeswax.
The beeswax was examined by Hübl's method, which consists in determinations — (1) the free-acid value, (2) the aaponification value, and the determination of the ratio of these two values.
The results are given in milligrams of caustic potash for 1 gram of beeswax. In each determination a blank experiment, using exactly the same quantities of alkali and alcohol, was performed simultaneously with that on the beeswax.
The following are the results of analysis:—
|Sample.||Melting-point.||Free-acid Value.||Ester Value.||Saponification Value.||Ratio.|
Lewkowitsch gives numerous estimations of European beeswax. In unbleached wax, he points out the following variations for normal beeswax:—
|Melting-point.||Acid Value.||Ester Value.||Saponification Value.||Ratio.|
These figures indicate that the beeswax used had rather a low saponification value, thus inferring the existence of much cerotin in the beeswax. This supposition was strengthened by the fact that on potash-lime fusion* of beeswax, and subsequent isolation and crystallization of the acids produced, a product was obtained melting near the temperature required for cerotic acid
Cerotic acid was prepared from this beeswax by Brodie's method—namely, extracting quantities of beeswax with successive volumes of ethyl alcohol until the free-acid value for 20 c.c. of the last extraction had been reduced to 2°90 c.c. N/10 KOH. Four extractions were necessary to do this.
[Footnote] * According to Gmelin, myricin contains varying quantities of cerotin and real myricin.
The free acid was precipitated by adding alcoholic lead acetate to the boiling solution. The insoluble lead salts were filtered off, and then boiled out repeatedly with alcohol to remove impurities.
The purified lead salts were then decomposed by glacial acetic acid, and the free acid, after washing with water, was extracted with boiling methyl alcohol in which, according to Marie,* melissic acid is insoluble. The solution thus obtained was filtered while hot, and the cerotic acid, which separated on cooling, was then found to melt at 75°5°.
The acid was purified by recrystallization from ethyl alcohol, acetic acid, and motor spirit. An acid was thus obtained melting† at 77°5° (Brodie gives 78° for cerotic acid).
Attempts to improve the process of obtaining cerotic acid by complete saponification of the beeswax with alcoholic potash, followed by the precipitation of the acids with alcoholic calcium-chloride, thus retaining the non-acid substances in solution, were fruitless. It was found that the calcium salts in presence of a saturated solution of high-molecular-weight alcohols were easily soluble, and that the precipitated calcium salts always contained a considerable quantity of organic impurities. Attempts with the lead salts, using the same method, were also unsuccessful.
Cerotic acid has hitherto been stated to crystallize in microscopic needles.‡ Although this is the case when prepared by Brodie's method, yet a careful fractionation of the ester of the acid obtained by the above method gives on hydrolysis a pure acid which crystallizes in pearly plates from acetic acid.
A titration of the cerotic acid purified by fractionation of the ester gave a molecular weight of 392°7, corresponding to the formula§ C26H52O2, thus confirming the formula of Lewkowitsch∥ and Henriques.¶
Derivatives of Cerotic Acid.
Cerotanilide.—This compound has not previously been prepared. It was obtained by heating cerotic acid with twice the theoretical quantity of aniline in a sealed tube to a temperature 150° to 170° for four hours. At the expiration of this period the mixture had formed a homogeneous dark soft solid. This was then washed with dilute acetic acid, in order to remove as much free aniline as possible. The anilide thus obtained was then dissolved in alcohol, the solution rendered alkaline with ammonia, and the unchanged cerotic acid precipitated by alcoholic calcium chloride. The filtrate from the insoluble calcium salts deposited the anilide on cooling. It was purified by crystallization from alcohol, acetic acid, and motor spirit.
The anilide thus obtained melted at 98°5° C., and the melting-point was unchanged by further crystallization.
[Footnote] * Journ. Chem. Soc., 1895, abs. I, 81.
[Footnote] † The melting-point of the purest cerotic acid obtained by the author was 78°. This was obtained by the conversion of the above acid into ester, and then by distillation under reduced pressure.
[Footnote] ‡ Beilstein, vol. 1, Supplement, p. 161.
[Footnote] § 1°5462 grams required 39°37 c.c. N/10 KOH.
[Footnote] ∥ Jahrb. f. Chemie, vol. 7, p. 369.
[Footnote] ¶ Zeit. f. Angew. Chem., 1897, p. 366.
The anilide is a white solid, fairly soluble in both alcohol and acetic acid, but more so in motor spirit, from which, however, it does not crystallize well.
The crystals from alcohol were large groups of fine needles, joined together in tree-like formation. The yield of the anilide was 55 per cent. of the theoretical.
On one occasion a sample of anilide crystallized from ethyl alcohol commenced to melt at 98°5°, but did not melt completely until a temperature of 118° was reached. After resolidification the sample melted sharply at the lower temperature; and the sample when crystallized from motor spirit also melted sharply at the lower temperature. There can be little doubt, therefore, that this anilide is dimorphous. The only other instance I can find of an anilide exhibiting dimorphism is that of acetanilide.*
Analysis of Cerotanilide.
|Cal. for C26H51O.C6H5NH.||Found.|
|N = 2°97||2·66|
|C = 81°52||81·56|
|H = 12°10||12·32|
Cerotone.—Two previous experimenters have worked upon the ketone of cerotic acid†: Brückner, by distilling the lead salt of cerotic acid, obtained a ketone melting at 62°: Nafzger, by the distillation of cerotic acid, obtained a ketone melting at 92°.
By applying the recently patented method of T. H. Easterfield and C. M. Taylor‡—namely, the heating of fatty acids with metallic iron, whereby stearic acid yields 80 per cent. of stearone—the ketone of cerotic acid was easily obtained. The details of the preparation are as follows: 9 grams of cerotic acid were heated for four hours with 0°69 grams of iron filings in an air bath slowly raised to a temperature of 340° to 350°. Carbon dioxide was evolved when the temperature had reached 280°. The temperature was now slowly raised until 340° was reached, and the air bath was then regulated and maintained at this temperature for four hours.
The ketone thus obtained was purified by the following procedure: I [ unclear: ] on was removed by boiling the ketone with dilute hydrochloric acid. Free fatty acid was then removed by boiling with dilute caustic soda. The soap thus formed was soluble in warm water, and was thus easily separated from the insoluble ketone. The ketone was now crystallized from motor spirit, and a pure product was obtained, which had a melting-point 93° C.
The melting-point was not changed by further crystallization from motor spirit or acetic acid. A 55-per-cent. yield was obtained by this method of preparation.
The ketone thus obtained is a white solid, fairly soluble in motor spirit and ethyl acetate, but sparingly soluble in acetic acid, from which it crystallizes in feathery flocculent masses. It is almost insoluble in hot alcohol, a saturated solution only becoming turbid on cooling.
[Footnote] * Hans Meyer, “Analyse und Constitutionsermittelung Organ Verbindungen,” p. 47.
[Footnote] † Beilstein, vol. 1, p. 1006.
[Footnote] ‡ N.Z. patent 27607.
Analysis of Cerotone.
|Calc. for C51H102O.||Found.|
|C = 83°83||83·50|
|H = 13°97||13·93|
Cerotone Oxime.—This compound is new. It was prepared as follows: 1 gram of ketone was dissolved in 150 c.c. of amyl alcohol, and one and a half times the theoretical quantity of hydroxylamine hydrochloride, with an excess of caustic potash to decompose the hydrochloride, was added, and the alcohol then boiled under a reflux condenser for eight hours. It was found that unless prolonged boiling took place a poor yield of oxime was obtained. The hot solution was then filtered from the inorganic salts, and the filtrate allowed to crystallize. The crystals were filtered off, and recrystallized from ethyl acetate.
The oxime thus obtained melted at 77°, and the melting-point was not changed by further crystallization. The oxime is easily soluble in hot ethyl acetate and amyl alcohol, but is only sparingly soluble in hot alcohol. The crystals from the ethyl-acetate or motor-spirit crystallizations are groups of radiating needles.
Analysis of Cerotone Oxime.
|Calc. for C51H103N.O.||Found.|
|N = 1°87||1·58|
|C = 82°14||82·15|
|H = 13°82||13·63|
Henpentecontane* 26 Ol.
This secondary alcohol is new, and was obtained by reducing the ketone, dissolved in amyl alcohol, with metallic sodium. 0°3 grams of cerotone were dissolved in 150 c.c. amyl alcohol and boiled under a reflux condenser, while, at intervals, small pieces of sodium, of total weight 2 grams, were added over a period of five hours. The solution thus obtained was shaken out with water in a separating-funnel. The solid was filtered off and crystallized from ethyl acetate. The melting-point of the alcohol thus obtained was 97°, and was unchanged by further crystallization.
Henpentecontyl Acetate.—This compound was obtained from the above-mentioned secondary alcohol by boiling it with a large excess of acetic anhydride under a reflux condenser for six hours.
The alcohol gradually dissolved in the acetic anhydride, indicating that acetylation was taking place. The solution was filtered while hot, and the filtrate, on cooling, deposited the acetate as a white solid. This was recrystallized from acetic anhydride, and after drying over caustic potash in a vacuous desiccator, melted at 60°5–61°5°. The melting-point was unchanged by further crystallization.
Analysis of Henpentecontyl Acetate.
|Calc. for C53H106O2.||Found.|
|C = 82·17||81·89|
|H = 13°69||13·57|
[Footnote] * “Henpentacontane” would sound more euphonious, but “henpentecontane” is philologically more correct.
It is interesting to compare S. Kipping's figures* for the secondary alcohol and acetates produced from ketones lower in the series with the data for henpentecontane 26 Ol. and acetate.
[The section below cannot be correctly rendered as it contains complex formatting. See the image of the page for a more accurate rendering.]
|Acid.||Ketone.||Alcohol.||Acetate.||Difference, Alcohol and Acetate.|
|S. Kipping Lauric||69°||75–76°||34–35°||41°|
|S. Kipping Myristic||76–77°||80°5–81°5°||45–45°5°||35°|
|S. Kipping Palmitic||82–834°||84–85°||47–49°||36°5°|
Ethyl Cerotate.—This compound was prepared from cerotic acid by dissolving the acid in absolute alcohol and boiling for twenty-four hours with 5 per cent. sulphuric acid. The ester obtained by this process was carefully washed free from sulphuric acid, dried in a vacuum, and then distilled under reduced pressure. The distillate crystallized from alcohol in colourless plates. It is easily soluble in alcohol, motor spirit and ethyl acetate, and acetic acid.
It boiled at 285° (14 mm.) and melted at 58.5–59°, and further crystallization did not raise the melting-point. Beilstein gives 59–60° as the melting-point of ethyl cerotate.
The following is a comparison of the melting-points of montanic and cerotic acids, and the melting-points of their ethyl esters:—
|Cerotic acid (78°)||58°5–59°||18°75°|
|Montanic acid (83°)||67°||16°|
Analysis of Ethyl Cerotate.
|Calc. for C28H56O2.||Found.|
|C = 79°24||79·14|
|H = 13°20||13·05|
B. Montanic Acid and Derivatives.
In Part I the isolation of pure montanic acid was described, and it was shown that it had a melting-point of 83°, and had a molecular weight corresponding to a formula C28H56O2.
Pure montanic acid crystallizes from acetic acid in colourless plates.§ It is fairly soluble in hot alcohol and glacial acetic acid, but is much more soluble in motor spirit and ethyl acetate.
Montanic acid is only slightly soluble in methyl alcohol. This fact is of interest, for, while cerotic acid is quite soluble in this solvent, melissic acid is said by Marie to be insoluble.
[Footnote] * Journ. Chem. Soc., 1893, p. 466.
[Footnote] ‡ Private communication, T. H. Easterfield and C. M. Taylor.
[Footnote] † Determinations by the author.
[Footnote] § Previous experimenters have reported montanic acid as crystallizing in needles.
Another feature of interest is the sparing solubility of the sodium soap in hot alcohol, for sodium cerotate dissolves without much difficulty.
Barium montanate is fairly easily soluble in hot ammoniacal alcohol, but calcium montanate is insoluble.
Montananilide.—This compound is new. It was prepared in a similar manner to cerotanilide. The pure anilide, after repeated crystallization, melted at 101°5°, and the melting-point was not changed by further crystallization.
Montananilide is soluble in those solvents mentioned for cerotanilide, but the solubility has decreased somewhat. It crystallizes from alcohol in groups of wavy needles.
The kjeldahl method was used for estimating the nitrogen.
|Calc. for C34H61O.N.||Found.|
|N = 2°80||2·40|
Montanone.—This ketone is new, and was prepared in a similar way to cerotone. The ketone, after repeated crystallization, melted at 97°5°, and the melting-point was not changed by further crystallization. A 50-per-cent. yield was obtained by this method of preparation.
Analysis of Montanone.
|Calc. for C55H100O.||Found.|
|C = 83°96||83·91|
|H = 13°99||14·03|
Montanone Oxime.—This compound was prepared in a similar way to cerotone oxime. The oxime, after repeated crystallization from ethyl acetate, melted sharply at 82°5°, and further crystallization did not raise the melting-point. Montanone oxime is a solid easily soluble in hot ethyl acetate, motor spirit, and amyl alcohol, but somewhat sparingly soluble in hot alcohol.
Analysis of Montanone Oxime.
|Calc. for C55H111O.N.||Found.|
|N = 1°74||1·74|
Ethyl Montanate.—This compound was prepared in a similar way to ethyl cerotate. The melting-point of ethyl montanate, after repeated crystallization from alcohol, was 67°, and this was unchanged by further crystallization. Ethyl montanate is a white solid, easily soluble in hot alcohol, from which it crystallizes in plates.
Analysis of Ethyl Montanate.
|Calc. for C30H60O2.||Found.|
|C = 79°64||79·41|
|H = 13°27||13·18|
Methyl Montanate.—This compound was prepared by heating 200 c.c. absolute alcohol with 1 gram of montanic acid and 20 c.c. strong H2SO4 in sealed tubes maintained at a temperature of 110° for three days.
The methyl montanate crystallized out in glistening spangles, and was filtered off and purified, by removal of any free montanic acid, by precipitation as the calcium salt. The filtrate from the insoluble calcium salt deposited methyl montanate on cooling, and this was purified
by crystallizing from ethyl alcohol. Thus obtained, methyl montanate melted at 67–67°5°. The melting-point was not changed by further crystallization.
Methyl montanate is a white soft solid, soluble in hot ethyl alcohol, and less soluble in methyl alcohol. It crystallizes from both solvents in glistening spangles.
Montanamide.—This compound was prepared in small quantity by heating 0°880 ammonia with ethyl montanate for three days in a sealed tube. It began to melt at 109°, and was completely melted at 111°. The sample was too small for analysis.
C.Mellisic Acid and Derivatives.
The melting-point of melissic acid obtained from montan wax was shown in Part I to be 88°5°. Schwalb* and Brodie‡ also give the melting-point of melissic acid prepared from beeswax as 88°5°. On account of the difficulty in obtaining melissic acid, only three derivatives could be prepared.
Melissone.—This ketone‡ was prepared from melissic acid obtained from both beeswax and montan wax. 0°5 grams melissic acid obtained from beeswax, and melting at 88°5°, was kindly placed at my disposal from laboratory stock.
Melissone was prepared in a similar way to cerotone and montanone. The ketone, after repeated crystallization, melted at 99°5–100°, and the melting-point was not changed by further crystallization. Melissone is a white solid, insoluble in the usual solvents, slightly soluble in hot ethyl acetate, and fairly soluble in amyl alcohol.
A 40-per-cent. yield was obtained by this method of preparation.
|Calc. for C59H118O.||Found.|
|C = 84°08||84·42|
|H = 14°01||14·06|
Melissone Oxime.—The small quantity of ketone remaining from the preceding preparation was utilized for the preparation of the oxime by a similar method to that employed in the case of cerotone and montanone oximes.
The oxime, after repeated crystallization from ethyl acetate, melted at 84°. The sample was too small for analysis.
Melissanilide.—This compound was prepared from melissic acid, derived from montan wax, in a similar way to the anilides of cerotic and montanic acids. The anilide, after crystallization from acetic acid and ethyl acetate, melted at 103°, and the melting-point was unchanged by further crystallization.
Melissanilide is a white compound easily soluble in ethyl acetate and motor spirit, and fairly soluble in alcohol.
[Footnote] * Annalen, 235, p. 135.
[Footnote] † Phil. Trans. Roy. Soc., 1848
[Footnote] ‡ Schwalb—“Non-acid Constituents of Beeswax” (Journ. Chem. Soc., 1885)—mentions that a ketone melting at 97–99° is produced during the potash-lime fusion of myricyl alcohol.
|Acid.||Amide.||Anilid.||Difference, Amide and Anilid.|
|62° Palmitic C16||101°||90°||11°|
|69° Stearic C18||109°||94||15°|
|Arachidic C20||108° (Feleto and Ponzio)|
|Behenic C22||111° (Feleto and Ponzio)|
|78° Cerotic C26||109° (Marie)||*98°5°||10°5°|
|83° Montanic C28||*109–111°||*101°5°||8°5°|
|88°5° Melissic C30||116° (Marie)||*103||13°|
|Acid.||Melting-point.||Ketone.||Oxime.||Difference, Ketone and Oxime.|
As the series is ascended the higher members have a smaller difference in melting-point between ketone and oxime than lower members.
|Melt. Pt.||Acid.||Anilide.||Ketone.||Oxime.||Amide.||Ethyl Ester.||Methyl Ester.|
|*78°||Cerotic||*98°5°||*93°||*77°||109° (Marie)||*58°5–59°||60° (Marie)|
|*88°5°||Melissic||*103°||*99°5–100°||*84°||116° (Marie)||75° (Marie)||74°5° (Marie)|
[Footnote] * Determinations by the author.
Part III.—Constitution of the Higher Fatty Acids.
It has been shown in Part I that three acids—cerotic, montanic, and melissic—exist side by side in montan wax. It was also shown in Part II that the properties of these three acids are closely related, and that their corresponding compounds are similar. It would hardly seem likely that three such compounds, possessing properties so closely related, should exist side by side in montan wax unless there be some simple constitutional relationship between them.
Experiments have been made to show the relation of these acids to one another and also to acids lower in the series.
(A.) The Relationship to Acids Lower in the Series.
Mai* showed that when the barium salts of palmitic or stearic acid were distilled with sodium methylate, hydrocarbons resulted. From barium palmitate he thus obtained n.-pentadecan and from stearic acid n.-heptadecan.
If barium montanate is heated with sodium ethylate, it should, if it behaves like palmitate and stearate of barium, give a hydrocarbon, n.-heptacosane, C27H56.
If this hydrocarbon is a normal primary paraffin it will be identical with the compound obtained by Krafft by the reduction of myristone, and montanic acid will then also contain a normal primary chain of carbon atoms. It will still remain uncertain whether the carboxyl group is at the end of the chain, for though the ease of bromination suggests that the bromine enters the chain in the a position, it does not show that the carboxyl group is at the end of the chain (isobutyric acid brominates more readily than normal butyric acid).
Calcium montanate when distilled with sodium ethylate gave a hydrocarbon, which after recrystallizing melted at 56°5–57°5°. A sample of normal heptacosane prepared by the reduction of the myristone with hydriodic acid melted at 59–60°. When equal quantities of the two hydrocarbons were mixed the product melted at 58–59°—i.e., half-way between the two. There can, under these circumstances, be little doubt that the hydrocarbon from montanic acid was only slightly impure n.-heptacosane, otherwise the mixture would have melted almost for a certainty at a lower temperature than the melting-point of the lower melting-point hydrocarbon.
(B.) The Relationship existing between the Three Higher Fatty Acids.
Attempts were made to degrade montanic acid to cerotic acid, but, although much work was done in this direction, no definite conclusion has been arrived at. It was hoped that degradation would be effected by the following procedure, which is based on that employed by Le Seur in the degradation of stearic acid*: (a) Formation of a brommontanic acid; (b) production of the unsaturated acid direct, or the formation of the a hydroxy acid and the conversion of this compound into the unsaturated acid; (c) the oxidation of the unsaturated acid into the lower homologue.
[Footnote] * Berichte, vol. 22, 1889, p. 2133.
The first step (a) took place without difficulty; in step (b) the a hydroxy acid was readily obtained, but all attempts to prepare the pure unsaturated acid were unsuccessful, and step (c) could not therefore be attempted.
Le Seur,* in the degradation of stearic acid to palmitic, also experienced considerable difficulty in the isolation of pure unsaturated acid (Δa oleic acid). He only obtained a 10-per-cent. yield.
The following is a brief description of the compounds isolated and the experiments made in connection with the degradation of montanic acid to cerotic:—
Brommontanic Acid.—Hell and Sadomsky's method† was used for the preparation of this compound. 6 grams of ethyl montanate were ground with 0°19 grams of dried red phosphorus, which had been previously freed from phosphorous acid by repeated washing with water. Anhydrous bromine was now added drop by drop to the mixture contained in a flask. There waa no violent action such as Le Seur records in the case of the formation of bromstearic acid. The contents of the flask were then warmed on the water bath for two hours under a reflux condenser. The condenser was now removed, and the excess of bromine allowed to escape. The molten mass thus obtained was poured into cold water. The crude brommontanic acid was melted twice in fresh water to decompose any acid bromide.
The crude brommontanic acid was then crystallized from acetic acid and motor spirit. By this means a pure compound was obtained, which melted at 75° C. The melting-point did not change on further crystallization.
Brommontanic acid crystallizes from acetic acid in colourless hexagonal plates. It is easily soluble in acetic acid and motor spirit; the yield obtained after two crystallizations was 60 per cent. of the theoretical.
|Calc. for C28H55BrO2.||Found.|
|Br. = 15°90||15·81|
Attempts to remove hydrobromic acid from brommontanic acid by means of pyridine, quinoline, and a concentrated solution of caustic potash did not result in the production of the unsaturated acid, as had been expected.
The hydroxy acid could easily be obtained, mixed with the unsaturated acid, by the action of 30-per-cent. alcoholic potash on brommontanic acid, but all attempts to remove water from it by means of ortho-phosphoric acid which had previously been heated to 200° were unsuccessful.
In conclusion, the author wishes to thank Professor Easterfield for suggesting this subject for research, and also for much practical advice, without which the writer could not have undertaken this investigation.
[Footnote] * Journ. Chem. Soc., 1904, p. 1708.
[Footnote] † Berichte, vol. 24, 1891, p. 2390.