322 
THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. [October 22 , 1870. 
maceutical literature, and for that reason the author 
deems the publication of the following remarks to be 
appropriate. 
There is no difficulty in distinguishing between 
bitter-almond oil and nitro-benzol when these sub¬ 
stances are pure and unmixed. The specific gra¬ 
vity of bitter-almond oil is from POT to TOIL or at 
the utmost 1'075 that of nitro-benzol is P20 to P29, 
so that Wagner has based on this difference a me¬ 
thod of determining the amount of nitro-benzol in 
bitter-almond oil. If at the same time advantage be 
taken of the solubility of the aldelyde in a solution 
of bisulphite of soda, it is possible to effect an ap- 
proximatively accurate separation of bitter-almond 
oil from nitro-benzol, leaving prussic acid out of ac¬ 
count.! However, it is but seldom that a quantitative 
determination is needed; more frequently the mere 
detection of nitro-benzol is alone requisite, and this 
must be attempted before the application of Wagner’s 
method, bv means of some characteristic reaction. 
Reactions of this kind have been suggested for the 
purpose by Maiscli and Dragendorff. The former 
relies upon the conversion of nitro-benzol into a 
brown resin by alcoholic solution of potash, and the 
conversion of bitter-almond oil into benzoate of pot¬ 
ash by the same reagent. Dragendorff has shown 
that these substances behave differently with sodium, 
—nitro-benzol becoming dark-coloured, while bitter- 
almond oil gives white flocks. However, Wagner 
regards both these methods as insufficient. Fliicki- 
ger quite agrees with him, and considers that the 
only reaction worth considering in regard to this sub¬ 
ject is the conversion of nitro-benzol into anilin and 
its coloured derivatives. Some anilin is formed 
even in Maiscli’s test, as was shown by Zinin; but 
much more is formed bv treating the nitro-benzol 
with hydrogen generated by zinc and hydrochloric 
acid, according to Hofmann’s plan, or by iron and 
acetic acid as Bechamp recommends,—the latter 
being the plan adopted in manufacturing anilin from 
nitro-benzol. 
Nitro-benzol may be readily recognized by dilut¬ 
ing it with alcohol, leaving it in contactwitli zinc and 
hydrochloric acid, and, when the evolution of gas has 
ceased, supersaturating with potash and producing 
the colour reactions of anilin. It is evident that this 
method would be applicable for detecting nitro-benzol 
in bitter-almond oil as well as in other liquids; and, 
although it has come into use, the author found a 
want of any statement as to its delicacy, and for that 
reason he undertook the following experiments. He 
finds it is not necessary to add alcohol, nor to sepa¬ 
rate the anilin formed, unless very great accuracy be 
required. The test is applied as follows: granulated 
zinc is covered with dilute sulphuric acid (I'll sp. 
gr.), adding the oil to be tested, and shaking up well; 
after about two hours the watery part of the liquid is 
to be poured on a moist filter. When heating has 
been prevented, the filtered liquid is colourless. The 
anilin salt on the filter may be, without further puri¬ 
fication, converted in the usual manner into coloured 
compounds by any of the suitable oxidizing agents. 
The author recommends chlorate of potash, chromate 
of potash or percliloride of iron. 
On adding to a small portion of the filtrate a few 
grains of chlorate, a violet colour is produced, or, with 
small quantities of anilin, a red colour. The cliro- 
* Gmelin, c Handbuch/ vi. 15. 
t Wagner; Frcsenius, Zeitsckrif't fur Analyt. Cliem. y. 286. 
mate produces a blue colour that soon passes into 
red, brown, dark green; percliloride of iron gives a 
red coloration. The action of chromate is very deli¬ 
cate ; but the chlorate is to be recommended as 
cleaner. If the latter salt does not react at once, a 
drop of concentrated sulphuric acid must be added, 
and the tube left for an hour or so. 
By this very simple test 1 per cent, of nitro-benzol 
may be detected with certainty in bitter-almond oil. 
The reactions are obtained also when only 1 or 2 
grins, of oil containing 1 per cent, of nitro-benzol is 
operated upon with 10 grins, granulated zinc, and 
10 grms. dilute sulphuric acid during 1 or 2 hours. 
Very intense colorations are produced when the ni¬ 
tro-benzol in the oil amounts to 5 per cent. 
HoAvever, it is not absolutely necessary to use hy¬ 
drogen or acids for producing it, in order to convert 
nitro-benzol into anilin. If bitter-almond oil contain¬ 
ing nitro-benzol be mixed with finely divided iron or 
zinc, and the pasty mixture exposed to a tempera¬ 
ture of 100° C. in a closed vessel for some hours or 
days, the formation of anilin takes place. It is 
facilitated by the addition of a little alcohol. After¬ 
wards, the mixture is diluted with some alcohol and 
filtered, the solution containing the etlierial oil and 
the anilin is mixed with some dilute sulphuric acid, 
so as to obtain sulphate of anilin in solution for 
testing. 
Pure bitter-almond oil treated in this way does not 
give any colour reactions. When the action of me¬ 
tallic iron or zinc upon the oil has been continued 
too long, the filtrate obtained after addition of sul¬ 
phuric acid is rather brownish, but even then chlorate 
of potash would not produce any blue, red, or green 
coloration if there were no nitro-benzol [^resent. 
Lastly, the author remarks that although a well- 
adjusted addition of alcohol, as well as nitro-benzol, 
to bitter-almond oil, would not affect the specific 
gravity, still 5 or 10 per cent, of spirit would be in¬ 
dicated by the action of fuming nitric acid. Equal 
volumes of true bitter-almond oil and of this acid mix 
together without disturbance, while the presence of 
alcohol would give rise to a violent reaction. 
Oil of cloves is so Avell characterized by its chief 
constituent, and is at the same time so cheap, that it 
is not likely to be much adulterated, unless it be with 
carbolic acid. 
If the acid be combined with bases, most of the 
etlierial oils that might have been added as adulte¬ 
rants would be recognizable by the smell they give 
to the remainder of the oil of cloves. Fat oils would 
show their presence bj r reduction of the specific gra¬ 
vity, and, excepting castor oil, by the reduced solu¬ 
bility in alcohol, which dissolves pure oil of cloves in 
all proportions. In order to detect carbolic acid, the 
author suggests the following test:—shake from 2 to 
10 grms. of the oil to be tested with 50 to 100 times 
as much hot water, and, after cooling, pour off the 
clear liquid. Add to a portion of this liquid a drop 
of ammonia, and then a pinch of chloride of lime. 
If the oil of cloves contains carbolic acid, the liquid 
then acquires, on shaking, a greenish colour that 
passes into blue, and lasts for some days. Pure oil of 
cloves does not give this reaction, if it be desired 
to apply this test very delicately, the liquid may be 
gently evaporated to a small bulk at a moderate 
heat .—Seine eitz. Wochensclirift fur Pharmacie. 
