DETECTION OF VARIOUS ADULTERANTS

11. DETECTION OF VARIOUS ADULTERANTS

The physical and chemical properties of several common adulterants (which have not been thoroughly discussed previously) are briefly noted here to aid the essential oil chemist.

I. Cedarwood Oil. 

This is usually found in the last fractions owing to the high boiling points of its constituents.

d₁₅ ...................................... 0.951 to 0.960

α_D ...................................... -28^o28' to -35^o39'

n_D²⁰ .................................... 1.5030 to 1.5059

Sol. 20^o ...............................Often insoluble in 10 vol. 90% ale.

II. Copaiba Oil. 

This also is found in the last fractions.

d₁₅ ...................................... 0.901 to 0.905

α_D .......................................-11^o18' to -14 ^o22'

n_D²⁰ .................................... 1.4972 to 1.4990

Sol. 20^o ...............................Insoluble in 10 vol. 90% ale.

III. Gurjun Balsam Oil. 

This is a high boiling oil.

d₁₅ ......................................  0.918 to 0.930

α_D ....................................... -35^o0' to – 130^o0'

n_D²⁰ ....................................  1.5010 to 1.5050

Sol. 20^o ...............................  Insoluble in 10 vol. 90% ale.

The following color reaction for this oil has been recommended:

To a mixture of 10 cc. of glacial acetic acid and 5 drops of concentrated nitric acid, add 5 drops of the oil: gurjun oil gives a purple-violet color within 2 min.

A rather elaborate test has been described by Deussen and Philipp²⁰⁵ involving the preparation and isolation of gurjun-ketone semicarbazone melting point, 234^o.

IV. Fatty Oils. 

Such oils greatly increase the ester number and evaporation residue of an oil. They are not volatile with steam, and cannot be distilled without decomposition except at exceptionally low pressures. In general, they are very insoluble in 90 per cent alcohol and frequently insoluble in 95 per cent alcohol ; castor oil proves an exception, being readily soluble in 95 per cent alcohol. The saponified oil frequently shows much foaming, owing to the formation of soaps.

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206 Liebigs Ann. 369 (1909), 57.