Wild volatile-oil plants and their economic importance

Part 3

Chapter 33,280 wordsPublic domain

To further confirm the above results, which seemed to indicate that the compound was identical with levo borneol, an elementary analysis was made.

0.1237 gram of the substance gave 0.3499 gram CO_{2}, corresponding to 77.2 per cent carbon.

0.1237 gram of the substance gave 0.1252 gram H_{2}O, corresponding to 11.4 per cent hydrogen.

C_{10}H_{18}O/borneol requires { 77.8 per cent carbon. { 11.7 per cent hydrogen.

The elementary composition substantiates the assumption that the crystals are identical with levo borneol.

CHEMICAL EXAMINATION OF THE OIL.

CHEMICAL CONSTANTS.

The usual chemical constants were determined, namely, the acid number, ester number, saponification number, and acetylization number.

The acid number, denoting the amount of free acids contained in the oil and expressed in milligrams of potassium hydroxid, was determined by simple neutralization of the oil with standard potassium hydrate volumetric solution.

The ester number, denoting the amount of esters (combination of alcohols and acids) in the oil and expressed in milligrams of potassium hydroxid, was determined by saponification of the ester compounds with alcoholic potassium hydrate.

The acetylization number, or the ester number determined after acetylization of the oil with acetic anhydrid, signifies the total amount of alcohol or alcohols in the oil.

The constants of the oil were determined with the following results:

Acid number, 2.5, calculated as acetic acid, indicates 0.26 per cent acetic acid.

Ester number, 25, calculated as bornyl acetate, indicates 8.7 per cent bornyl acetate, which is equivalent to 6.8 per cent of free borneol.

Saponification number, 27.5.

Acetylization number, 139, corresponds to 42.67 per cent of total borneol in the oil, or, deducting the 6.8 per cent of free borneol as the ester, to 38 per cent of free borneol.

Assuming that the stearoptene obtained was borneol, a determination of the constants of the stearopteneless oil was made. The acid number remained practically the same, being 2.3; the ester number differed only very slightly, being 24.7; but the acetylization value obtained was only 132, which corresponded to but 40 per cent of total borneol. This is in strict conformity with the assumption, which seemed to be sufficiently proved, that the stearoptene separated from the oil by freezing was borneol. The stearopteneless oil was nearly 3 per cent poorer in borneol than the original oil, as shown above. It is to be remembered that 3 per cent of crystalline borneol was removed by freezing the original oil, hence the lowering of the borneol content of the stearopteneless oil.

FREE ACIDS.

The determination of the free acids was accomplished by repeatedly shaking a portion of the original oil with a 10 per cent sodium carbonate solution. After removing the adhering oil from the alkaline liquid by shaking with ether, the solution was acidified and distilled with a current of steam. A few oily globules floated on the surface of the liquid. These were extracted with ether and the ether evaporated. A small amount of oily residue remained, which was distinctly acid. The oily residue was exactly neutralized with sodium hydrate and precipitated with silver nitrate solution in three fractions:

Fraction 1. 0.0377 gram silver salt gave 0.0162 gram silver = 42.9 per cent silver.

Fraction 2. 0.0206 gram silver salt gave 0.0091 gram silver = 44.1 per cent silver.

Fraction 3. 0.0663 gram silver salt gave 0.3000 gram silver = 45.2 per cent silver.

The three fractions appear to be a mixture of caprylic and œnanthylic acids. Silver caprylate requires 42.9 per cent silver; silver œnanthylate requires 45.5 per cent silver.

A small amount of the insoluble free acids was therefore caprylic acid (octoic acid), the major portion being œnanthylic acid (heptoic acid).

The distillate from which the oily acids were extracted by ether was still slightly acid and was accordingly neutralized with sodium carbonate and precipitated with silver nitrate, two fractions being obtained. The first corresponded to silver carbonate, due to a slight excess of sodium carbonate; the second, only trifling in quantity, indicated the presence of only a trace of formic acid in the free condition.

Œnanthylic, or heptoic, acid seems to be the predominating free acid in the oil, with slight traces of formic and caprylic, or octoic, acids.

COMBINED ACIDS.

The esters in the oil, being combinations of alcohols and acids, serve as a basis for the identification of the acids in combination. In order to accomplish a separation of the combined acids a small quantity of the oil was saponified with alcoholic potassium hydroxid by heating on a water bath for half an hour. After dilution of the mixture with water and separation of the oil the alkaline liquid, which contained a small amount of the oil held in suspension, was shaken out with ether. The liquid was then acidified with sulphuric acid and distilled with steam. The oily globules which separated on the distillate were extracted with ether and the solvent evaporated. A small amount of an oily liquid with very offensive odor remained. This mixture of oily acids was neutralized with sodium hydrate and precipitated with a dilute solution of silver nitrate. Two fractions resulted:

Fraction 1. 0.0430 gram silver salt gave 0.0160 gram silver = 37.2 per cent silver.

Fraction 2. 0.0440 gram silver salt gave 0.0197 gram silver = 44.7 per cent silver.

From the results obtained it is evident that the fractions consist of the silver salt of undecylic acid, which requires theoretically 36.8 per cent of silver, and silver salt of heptoic (œnanthylic) acid, which requires 45.5 per cent of silver.

The aqueous distillate from the above, after being made neutral with sodium carbonate, was evaporated to small volume and precipitated in three fractions with silver nitrate:

Fraction 1. 0.243 gram silver salt gave 0.1837 gram silver = 75 per cent silver.

Fraction 2. 0.3255 gram silver salt gave 0.2370 gram silver = 72.9 per cent silver.

Fraction 3. 0.3492 gram silver salt gave 0.1840 gram silver = 52.9 per cent silver.

The greater portion of the soluble combined acids consisted of valerianic acid, the silver salt requiring 51.6 per cent of silver. A trace of formic acid was also indicated in combination as an ester in fraction 2, above.

The chief acids in combination as esters in the oil appear to be œnanthylic (heptoic) and valerianic, the former being preponderant. Formic and undecylic acids occur only as traces. All of the above are no doubt combined in the oil as esters of borneol.

FRACTIONATION OF THE VOLATILE OIL.

One hundred grams of the original oil were subjected to fractionation and separated into six fractions of 5 degrees each, beginning with 175° C. Those fractions together with the residue were again fractionated in order to insure a better separation of the constituents.

+Table IV.+--_Fractionation of oil of wild sage, showing the physical and chemical properties of the fractions._

+------------+-----------+--------+----------+-------+--------------- | | |Specific| Rotation | Ester | Fraction.|Temperature.|Distilled. |gravity |in 50 mm. |number.| Remarks. | | | at | tube. | | | | | 24° C. | | | ---------+------------+-----------+--------+----------+-------+--------------- |_Degrees C._|_Per cent._| |_Degrees._| | 1 |Below | 13.6 | 0.9084 | - 9.5 | 2.6 |Eucalyptuslike | 175[31] | | | | | (cineol) odor. 2 |175 to 180 | 14.0 | .9196 | - 8.1 | 6.7 | Do. 3 |180 to 185 | 6.0 | .9269 | - 7.6 | 8.9 | Do. 4 |185 to 190 | 4.5 | .9313 | - 6.4 | 12.0 |Slightly | | | | | | camphoraceous | | | | | | odor. 5 |190 to 195 | 10.0 | .9401 | - 8.6 | 25.8 |Camphoraceous | | | | | | odor. 6 |195 to 205 | 9.5 | .9478 | - 9.7 | 34.8 |Decidedly | | | | | | camphoraceous; | | | | | | free borneol | | | | | | crystallized | | | | | | in condenser. 7 |205 to 215 | 9.0 | .9562 | -10.6 | 56.4 |Fraction almost | | | | | | solid | | | | | | (borneol). 8 |215 to 230 | 9.5 | .9600 | -10.8 | 75.2 |Fraction | | | | | | partially | | | | | | solidified. 9 |230 to 245 | 3.5 | .9570 | - 5.8 | 70.7 |Few crystals | | | | | | separated. 10 |245 and | 9.0 | .9830 |..........| 47.0 |Dark, sirupy, | above | | | | | camphoraceous. ---------+------------+-----------+--------+----------+-------+---------------

IDENTIFICATION AND SEPARATION OF THE CONSTITUENTS.

_Cineol._--Fraction 1, 175° C., possessed a strong eucalyptuslike odor and was tested for cineol by means of iodol. The tetraiodopyrol (iodol) addition product of cineol formed into well-defined, nearly colorless crystals, melting at 110° to 113° C. This crystalline addition product of iodol formed in the first four fractions; in fraction 5, however, only a trace of crystals appeared.

The presence of cineol having been proved, a quantitative estimation of the compound was made in fractions 1, 2, 3, and 4. Fraction 5, which contained only a very small quantity of cineol, did not admit of estimation by the phosphoric-acid method, which is reliable only when large percentages of cineol are present.

The fractions yielded the following percentages of cineol: 1, 40 per cent; 2, 70 per cent; 3 and 4, 43.7 per cent. Calculating from the original oil as a basis, the above results correspond to 19.7 per cent of cineol in the original oil.

_Fenchone._--Fraction 5, boiling from 190° to 195° C., was a heavy liquid with a strong camphorlike odor. Pure levo fenchone[32] from thuja oil is an oily liquid with a strong camphoraceous odor; boiling at 192° to 194° C.; specific gravity at 19° C., 0.946; (A_{D}) -66.9°.

An oxime was prepared from the fraction by reaction with hydroxylamine hydrochlorid according to the method of Wallach,[33] which is as follows: To 5 grams of fenchone dissolved in 80 cubic centimeters of absolute alcohol is added a solution of 11 grams of hydroxylamine hydrochlorid in 11 grams of hot water. Six grams of powdered potash are added. The oxime separates in the form of crystals, upon standing for some time. Recrystallized from alcohol it melts at 164° to 165° C.

The oxime formed from the fraction by the above method, after recrystallization from ethyl acetate, melted at 170° C.

Provided that fraction 190° to 195° C. consists chiefly of fenchone the oil should contain 8 to 10 per cent of this compound.

_Borneol._--The total amount of borneol contained in the oil was determined by the saponification of a small quantity of the original oil and subsequently fractionating the saponified oil. Twenty-five grams of the saponified oil were carefully fractionated and then refrigerated, 7.5 grams of borneol separating out. This corresponds to a total of 30 per cent borneol. After the separation of the borneol the oil was again fractionated, and the portion above 195° C. yielded, when frozen, an additional 2 grams of borneol, making a total of 9.5 grams, or 38 per cent, of total borneol separated from the oil. The theoretical quantity of borneol in the oil, as shown by the acetylization value, is about 43 per cent, the lower percentage which was actually obtained being caused by incomplete separation due to the smallness of the amount saponified.

_Esters of borneol._--A careful examination of Table IV shows that the esters of borneol, possibly chiefly bornyl heptoate and valerianate, are found in the fractions boiling above 190° C., principally in the highest boiling fractions; a perfect separation of these esters was not feasible because of the existence of the esters as mixtures of several acids. The ester numbers of the fractions, however, show the distribution of the esters at the different temperatures.

SUMMARY.

Briefly summarizing the results of the analyses, the oil of wild sage may be said to be composed: (1) Of total borneol camphor, 43 per cent, of which about 6.8 per cent exists as bornyl heptoate (calculating the esters of the oil as heptoic acid salts of borneol), leaving 35.8 per cent of free borneol camphor present in the oil; (2) of cineol (eucalyptol), 18 to 20 per cent; (3) of fenchone, 8 to 10 per cent; (4) of free acids, chiefly œnanthylic, or heptoic, acid, 0.58 per cent, with traces of formic and caprylic acids; (5) of combined acids in form of esters, chiefly, œnanthylic acid, with smaller quantities of valerianic, undecylic, and formic acids. It is very probable that a small amount of terpenes were also present in the portion distilled below 175° C., which, however, were not identified.

As will be noted from the above, the chief constituents of the oil of wild sage are borneol camphor and cineol, each of which possesses valuable antiseptic qualities. Since there is a high percentage of these constituents, the oil from this wild plant should prove of value for medicinal purposes. Another important use of the oil is suggested by the high content of borneol, a constituent which finds application in celluloid manufacture, and which is readily separated from this oil. Lastly, combining the agreeable aromatic quality with its antiseptic qualities, the oil should prove important as an ingredient of medicinal soaps or as a scenting substance.

Inasmuch as the wild sage plant grows chiefly on sandy and stony hills which are practically waste lands and which require but little moisture, it would seem that the plant could be cultivated in various sections of the Northwestern States.

SWAMP BAY.

BOTANICAL DESCRIPTION AND DISTRIBUTION.

_Persea pubescens_ (Pursh.) Sarg., commonly known as swamp red bay or swamp bay (figs. 5 and 6), is an aromatic evergreen tree attaining a height of 30 feet or more, but usually occurring as a shrub. The leaves and twigs of the tree possess a pleasant camphoraceous odor. The swamp bay occurs abundantly in swamps and hammocks from North Carolina to Florida and Texas. The tree is a member of the family Lauraceæ, to which the camphor tree belongs.

DISTILLATION OF THE OIL.

Because of the strong camphoraceous odor and its close relationship to the camphor tree, the extraction and possible utilization of the oil from this wild aromatic plant suggested itself. Accordingly, during the summer of 1910, with the assistance of Mr. S. C. Hood, in charge of the station at Orange City, Fla., a small quantity of the leaves and twigs of this plant was distilled and a yield of about 0.2 per cent of oil was obtained. But with proper conditions and precautions the yield could no doubt be very materially increased, depending largely upon the time at which the distillation is made, and also upon the proportion of twigs and branches included. The above distillation was made late in the summer, long after the blossoming period, the stage at which a plant is usually most productive in volatile oils, and the material also contained many branches and much woody matter.

The oil obtained was pale yellowish brown in color, with a strongly aromatic and camphoraceous odor, and a persistent bitter, slightly pungent, and camphorlike taste. The specific gravity at 25° C. was 0.9272; specific rotation, A_{D} = +22.4°; refraction, N_{D} 25° = 1.4695. The oil was soluble in one-third its volume of 80 per cent alcohol, becoming faintly turbid upon the addition of five volumes or more of alcohol.

CHEMICAL EXAMINATION OF THE OIL.

CHEMICAL CONSTANTS.

A preliminary examination of the oil disclosed considerable free acidity, the acid number being 2.8, while the ester content was rather low, the ester number being 14.5. The low ester number would seem to indicate a low percentage of alcoholic compounds in combination with acids, and would correspond to 4.9 per cent of esters calculated as the acetate of borneol. After acetylization of the oil with acetic anhydrid the saponification number was found to be 64, which corresponds to 14.6 per cent of free alcohol, calculated as borneol.

In order to identify conclusively the constituents of the oil and the forms in which they occur, and to separate quantitatively the predominant constituents, the oil was subjected to a more careful and detailed analysis.

FREE ACIDS.

The free acidity of the oil as indicated by the preliminary tests was removed by shaking with 10 per cent aqueous sodium carbonate solution in several portions. The aqueous alkaline extracts, after being deprived of any adhering oil by extraction with ether, were concentrated, acidified, and distilled with a current of steam. The acids which were obtained separated principally as oily globules on the aqueous distillate, which was only faintly acid.

The free insoluble acids which were separated from the aqueous distillate by extraction with ether and evaporation of the solvent were neutralized with a solution of potassium hydroxid and then precipitated in fractions with a solution of silver nitrate.

Fraction 1. 0.0227 gram silver salt gave 0.0130 gram silver = 57.2 per cent silver.

Fraction 2. 0.0213 gram silver salt gave 0.0119 gram silver = 55.8 per cent silver.

It appears from the above results that the only acid existing in the free state in the oil is butyric acid, since silver butyrate gives theoretically 55.3 per cent of silver, fraction 1 being slightly contaminated, due possibly to a slight excess of potassium hydrate which was added when the acids were neutralized and which would appear in the first precipitate.

From the remaining faintly acid distillate, after neutralization with barium carbonate and concentrating, only a trace of precipitate, insufficient for silver determination, resulted upon the addition of silver nitrate solution. The butyric acid detected in the free insoluble acids was evidently extracted by the ether, in which it is very soluble.

COMBINED ACIDS.

As stated previously, the oil was found to contain a small percentage of esters, or organic acids in combination with higher alcohols. In order to identify these acids, which are in combination in the form of esters, a quantity of the oil, after removing the free acids, was saponified by heating on a water bath for half an hour with a slight excess of alcoholic potassium hydroxid. The mixture, after saponification, was diluted with water and the unsaponified oil separated. The alkaline liquid, which now contained the combined acids as their potassium salts, after being freed from adhering particles of oil by shaking with ether, was acidified with sulphuric acid and distilled with steam. The insoluble oily acids which formed on the distillate were separated by shaking the distillate lightly with ether and evaporating the ether.

SOLUBLE COMBINED ACIDS.

The aqueous portion of the distillate which contained the soluble combined acids of the oil was neutralized with barium carbonate, concentrated and precipitated with silver nitrate solution. Only a small precipitate resulted. This precipitate was found to contain 55.9 per cent of silver, which corresponds to silver butyrate. Hence the acid in the distillate was butyric acid.

INSOLUBLE COMBINED ACIDS.

As heretofore stated, the insoluble oily acids obtained by extraction with ether were carefully neutralized with potassium hydroxid solution and precipitated fractionally with silver nitrate. Two precipitates were obtained which were thoroughly washed and dried. The first and largest precipitate assayed 51.2 per cent silver, the second assaying 45.1 per cent silver. This would indicate that the insoluble acids were valerianic acid (silver valerianate requiring 51.6 per cent silver), and heptoic acid (silver heptoate requiring 45.5 per cent silver), the valerianic acid predominating.

The results show that the esters of this oil exist as the salts of butyric, valerianic, and heptoic acids, valerianic acid esters, however, predominating.

FRACTIONATION OF THE OIL AND SEPARATION OF THE STEAROPTENE.

For the purpose of accomplishing a separation of the constituents, 50 grams of the oil, after saponification, were dried and subjected to fractional distillation in a three-bulb Ladenburg flask. The results are given in Table V.

+Table V.+--_Fractionation of saponified oil of swamp bay and description of fractions._