Oleum Lauri foliorum. - Lorbeerblatterol. - Essence de Laurier.

Origin. The laurel oil of commerce is distilled from the leaves of the laurel, Laurus nobilis, L. According to the quality of the leaves the yield varies between 1 and 3 p. c.

Properties. Laurel leaf oil is a light yellow liquid, the odor of which at first reminds one of cajuput oil, but later is rather sweetish. d16o0,915 to 0,932; aD - 15 to - 18°; nD20o1,467 to 1,477; A.V. up to 3,0; E.V. 28 to 50; E.V. after acetylation 58 to 78 (2 determinations); soluble in 1 to 3 vol. of 80 p.c. alcohol; some oils, particularly French ones, are also soluble in from 3 to 10 vol. of 70 p. c. alcohol. In addition to the oils distilled in France and Germany, other kinds are in the market. In this connection mention should be made of oils of very good quality distilled along the coast and in the islands of the Medit-terranean and in Palestine. In the accompanying table the properties of various oils have been compiled1): -

d15o

aD

nD20o

A.V.

E.V.

E.V.

after acetyl.

Soluble

German and French . ...

0,915 to 0,932

- 15° to

- 18°

1,467 to

1,477

up to

3,0

28 to 50

58,3 to

77,7

in 1 to 3 vol. of 80 p.c. alc, some (part. French) sol. in 3 to 10 vol. of 70 p.c. alc.

Fiume . . ......

0,9281

-13° 52'

1,47156

1,0

31,9

-

in 2,5 vol. and more of 70 p.c. alc.

Corfu ..............

0,9177 to 0,9211

- 16° 40' to - 21° 40'

1,46862 to 1,47107

up to

1,5

29,8 to

43,8

36,2 to 83,5

in 1 to 2 vol. of 80 p.c.

ale, mostly in 3 to 6 vol.

of 70 p.c. alc.

Cyprus ... ..............

0,934 to 0,944

- 4° 40' to

- 5° 40'

1,466 to

1,474

up to

1,8'

22 to 25

62 to

96

in 2 to 3 vol. or more of 70 p.c. alc.

Palestine. .........

0,916 to

0,924

- 14° to

- 21°

1,465 to

1,469

up to

2,2

21 to 49

43,2 to 81,4

in 1 to 2 vol. of 80 p. c.

alc, some in 4 to 7 vol.

of 70 p.c. alc.

Asia Minor.......

0,9268

- 15°50'

1,46575

0,8

34,8

60,1

in 1 vol. or more of 80 p.c. alc.

Dalmatia . ........

0,9268

- 14° 36'

1,46813

0,5

29,9

68,6

in 2,5 vol. or more of 70 p.c. alc.2).

Syria ................

0,9161

- 14° 20'

-

-

-

-

in 1 vol. or more of 80 p.c. alc.3).

1) Report of Schimmel & Co. April 1909, 60.

2) Ibidem October 1911, 56.

3) Berichte von Roure-Bertrand Fils April 1911, 26.

Composition. As was first pointed out by Wallach1), the lowest fraction contains a-pinene (m.p. of nitrol piperidine 118°), more particularly the laevogyrate modification thereof2), presumably also phelIandrene2). Of oxygenated constituents the following have been identified: cineol1), l-linalool (m. p. of phenyl-urethane 65°; oxidation to citral)3), geraniol (m.p. of diphenyl-urethane 83°; oxidation to citral, m. p. of citryl-B-naphthocin-choninic acid 197°)4), eugenol (m.p. of benzoyleugenol 70°)6) and methyleugenol (m.p. of veratric acid 178°)3). The highest boiling portions appear to contain sesquiterpenes and sesquiterpene alcohols4) that have not been further investigated.

The acid reaction of the oil is due to acetic, isobutyric and isovaleric acids4). The esters are composed on the one hand of the alcohols linalool and geraniol, also of the phenol eugenol, on the other hand of a mixture of acids in which Thorns and Molle have identified the following acids: acetic acid, valeric acid, capronic acid and an acid C10H14O2 which melts at 146 to 147°.

As to the quantitative composition of the oil, Thorns and Molle found it as follows: free eugenol about 1,7 p.c, esterified eugenol about 0,4 p.a, cineol 50 p.c. The acid C10H14O2 constitutes 0,07 p.c. of the oil. The higher fatty acids were present in the ratio of 40 p.c. of valeric acid to 60 p.c. of capronic acid.