Chemistry of Essential Oils

LABIATE 215

PHYSICAL PROPERTIES AND CHEMICAL COMPOSITION OF PEPPERMINT OIL

DISTILLED FROM THE FRESH AND FROM THE DRY HERB AT VARIOUS

STAGES OF GROWTH DURING SUCCESSIVE YEARS.

DescriptionYear and of

Material.

1908.

Fresh Herb:

Budding.

Flowering.

Fruiting.

1909.

Fresh Herb:

Budding.

Flowering.

Fruiting.

Dry Herb:

Budding.

Flowering.

Fruiting.

Physical Properties.

Colour. Odour, and

Taste.

Pale yellow; pleasant

menthol-like odour;

cooling taste

Pale yellowish-green;

pleasant ester-like

odour; very pun-

gent taste

Yellowish-green ;

pleasant minty

odour; less pungent

and cooling taste

Golden-yellow; pleas-

ant, faint odour;

slightly pungent

and cooling taste

Pale yellow; agree-

able menthol-like

odour; pungent

minty taste

Straw coloured; very

flowery odour;

minty, pungent,

taste

Greenish -yellow;

strong minty odour;

pungent, minty

taste

Golden -yellow;

minty odour; pun-

gent, minty, slight-

ly fatty taste

Yellow ; unpleasant

minty odour; strong,

pungent, minty

taste

Specific

Gravity.

0-912

•924

-918

-9158

•9203

•9151

1

-9337

(^1) -9163
1
'9344
Rota-
tion,
50 mm.
Tube.

°C

- 15-8

- 4-5

-21

- 9-2

-10-6

- 8-3

-13-1

-13-5

- 8-1

Refrac-

tion.

1-4696

1-4728

1-4681

1-4738

1-4662

1-4676

1

1-4695

2l-4695

1-4718

Solubil-

ity in

80 per

Cent.

Alcohol.

Vols.

1-5

1-25

1-5

1

1-2

•8

3

1-2

n

Chemical Composition

(per Cent.).

Free

Acid

(as A-

cetic).

0

0

0

•10

•21

•10

•17

•16

•36

I?!

Ace-

tate).

9 55

14-50

i

Menthol.

Free.

30 56

23-97

24 40 34-33

6-72

7-07

12-37

13-26

12-73

17-68

30-1

46-5

33-8

36-07

37 - 37

34-2

Total.

38-08

35-39

53-55

35-39

52-09

43-58

46-38

47-44 j

48-16

(^1) At 22° C. 2 At 25° C. (^3) Turbid in excess.

• Turbid in 1 volume absolute alcohol; insoluble 5 in 80 and 90 per cent, alcohol in any proportion.
  Turbid in 2 volumes or more.