Chemistry of Essential Oils

277

Jasminum paniculatum is a white-flowered species, used in China

for scenting tea.

Jasminum revolutum is also a native of China, and bears yellow

flowers with a very fragrant odour.

Jasmin oil prepared from the pomade has the following characters :—

Specific gravity.

Optical rotation

Esters as benzyl acetate

0-920 to 1-020

• 1° to + 4° 15'
  41 to 73 per cent.

Differences of opinion have been expressed as to the composition of
this .oil. Verley
l
extracted the pomade with acetone and obtained, after
evaporation of this solvent in vacua, 40 grms. of oil, which on distilla-
tion in vacua left 40 per cent, of resin and yielded 60 per cent, of
essential oil. Verley concluded that the oil was approximately com-
posed of 10 per cent, of linalol and 90 per cent, of phenyl-glycol-
methylene-acetal (C 9 H 10 O 2 ), which he termed jasmal. These researches
led to the granting of a French patent for the production of this body
synthetically, as an artificial jasmin oil. The specification states that
50 grms. of phenol-glycol, 30 grms. of sulphuric acid, diluted with 125
grms. of water, and 100 grms. of formic aldehyde are to be heated on a
water-bath. The resulting body when purified boils at 218°, and is said
to have a strong jasmin odour. On the other hand, Hesse and Miiller,^2
who have examined a very large number of samples of this oil, state
that they have most carefully examined the oil, and assert that there is
not a trace of this body present, but that the main constituent is benzyl
acetate. The following are the figures they give for ten samples of oil
prepared by themselves from the pomade:—

No.

1 2 3 4 5 6 7 8 9

10

Yield

per Cent.

•427

•457

•429

•473

•409

•395

•595

•490

•526

•480

Specific

Gravity.

1-015

1-018

1-011

1-009

1-006

1-007

1-014

1-012

1-009

1-015

Rotation

+ 2° 30'

+ 2° 30'

+ 2° 30'

+ 3° 30'

•1- 3° 15'

+ 3° 10'

+ 3° 20'

+ 3° 10'

+ 3° 30'

+ 3° 20'

Esters—

calculated as

Linalyl

Acetate.

Per Cent.

95-4

91-5

95-0

92-0

90-3

90-9

92-8

94-1

95-4

93-3

Benzyl

Acetate.

Per Cent.

73-0

70*0

72-9

70-4

69'1

70-7

71-0

72-0

73-0

71-4

They have made a very careful and exhaustive examination of the

oil, and have studied quantitative methods for estimating its com-

ponents, which led them to the conclusion that the average composi-

tion of the oil is as follows:—

1

Comptes rendus, 128 (1899), 314.^2 Bericht, 32 (1899), 565, 765.