Chemistry of Essential Oils

30 THE CHEMISTEY OF ESSENTIAL OILS

Specific gravity 0'860 to 0-866

Optical rotation.+ 34° „ + 47°

Refractive index 1-4670 „ 1-4740

Distillate from 152° to 156° 5 to 10 per cent.

„ 156° „ 160° 80 „ 85

The turpentine oil from Pinus longifolia has recently been examined
by Simonsen.^1 He found present \the following bodies: laevo-a-pinene,
/3-pinene, a new terpene for which he proposes the name d-carene, and a
new sesquiterpene which he terms longifolene. In the previous edition
of this work (p. 28) it was stated that 3-sylvestrene was present in com-
paratively large amount.
It is probable that this is incorrect, but that another terpene has been
mistaken for sylvestrene on account of the fact that by the action of
hydrochloric acid, a molecular rearrangement takes place, with the
formation of sylvestrene hydrochloride. This hydrocarbon is that
isolated by Simonsen and named by him d-carene. It is an oil having
the following characters :—

Specific gravity @ 30°. 0-8586

Refractive Index @ 30° 1-4690

Optical Rotation : + 7-69°

Boiling-point at 705 mm.168° to 169°

It yields sylvestrene hydrochloride when treated with hydrogen chloride

in ethereal solution. It yields a crystalline nitrosate, decomposing at

141-5°.

Its constitution is not yet settled. The sesquiterpene ^-longifolene

boils at 150° to 151° at 36 mm., or at 254° to 256° at 706 mm. Its

specific gravity is 0*9284 at 30°, refractive index, 1-4950 at 30°, and optical

rotation + 42'73°.

It yields a hydrochloride melting at 59° to 60°, and having a specific

rotation + 7*1°. Its hydrobromide melts at 69° to 70°, and its hydrio-

dide at 71°.

The characters of this oil fall within the following limits :—

Specific gravity 0*865 to 0-875

Optical rotation 0° to + 4°

Initial boiling-point 165°

Two samples on fractionation by Eabak^2 and by Schimmel & Co.^3

gave the following results:—

Rabak. Schimmel.

165° to 170° 56 per cent., aD = -2° 33 per cent., aD = - 3° 30'

170° „ 175° 20 „ „ = + 2° 48' 31 „ ,. = + 0° 40

175° ,,180° 9 „ ,,= +6° 50' 14 „ „= + 4° 32'

above 180°. 15 „ „ = + 18° 12' 22 „ „ = + 16° 22'

Austrian turpentine oil is derived principally from Pinus laricio. Its

composition has not been exhaustively studied, but it consists of terpenes

and is similar in composition to French turpentine oil. Its characters

are as follows :—

(^1) Jour. Chem. Soc. (1920), 570.
(^2) Pharm. Rev., 23 (1905), 229. s Report, April, 1906, 63.