Chemistry of Essential Oils

LABIATE 237

1

2

3

4

Specific Gravity.

0-917

0-918

0-921

0-927

Rotation.

+ 17° 30'

+ 28° 30'

+ 46°

+ 55°

Refractive Index.

1-5030

1-5043

1-5061

1-5082

Other samples of African copaiba oil had the following characters :—

Specific gravity 0-919 to 0-932

Rotation + 30° „ + 37°

Refractive index 1-4999 „ 1-5040

Two of these on fractionation showed the following variations in

optical rotation and refractive index :—

25 per cent..

25..

25 „..

20 „..

5 ,, residue

I.

Rotation.

+ 16°

+ 19°

+ 24°

+ 48°

Refractive

Index.

1-4960

1-4965

1-4980

1-5089

II.

Rotation.

+ 24°

+ 26°

+ 29°

+ 43°

Refractive

Index.

1-4975

1-4980

1-4981

1-5090

OIL OF SPEARMINT.
There are several different essential oils known under the name
spearmint oil; the botanical origin of the plant used for distillation
differing with the country in which the plant is grown. In the United
States and in this country several varieties of Mentha viridis (Mentha
spicata), are distilled. In Eussia the plant distilled is Mentha vertieellata,
and in Germany either Mentha spicata, var. crispata, or Mentha longi-
folia.
The principal types of this oil have the following characters :—

American Spearmint Oil.

Specific gravity ....

Optical rotation.

Refractive index....

Acid value.

Ester „

Carvone (neutral sulphite method)

0-920 to 0-940 (rarely higher)

• 35° to - 53°
  1-4800 „ 1-4890
  0 „ 2
  18 „ 36
  35 to 66 per cent.

The oil is soluble in 1 to 1'5 volumes of 80 per cent, alcohol.

English Spearmint Oil.

Specific gravity 0

Optical rotation -

Carvone

0*926 to 0-935

• 39° „ - 52°
  30 to 48 per cent.