The object of this work has been to find
suitable qualitative tests for some classes of organic
compounds. The reaction must be applicable to 0.5 g.
or less, of the compound, and to every member of the
series. The resulting derivative must have a good
crystalline structure and melting point; must be
easily prepared and be stable. .The melting points
of such derivatives must differ by at least 5°C. from
one member to the next.
Substituted hydrocarbons have been oxidised
in sealed tubes with nitric acid (sp. gr. 1.2) to the
corresponding acids. 0.5 g. substance and 5 c.c.
acid were used in each experiment. The yields and
melting points of the acids obtained and the
peculiarities of each experiment have been noted.
Aliphatic amines have been identified by the
use of various substituted phenylisothiocyanates.
(3- naphthylisothiocyanate has been found to be the most
suitable. The amine derivatives have good melting
points, crystalline structures, and separate readily
from solution. 2:4:5- rinitrotoluene has been used
to detect primary aliphatic amines in small quantity
but is useless as a general reagent for aliphatic
α-phenylindole has been used for the classification of alkyl nitrites, (3- isonitroso-α- phenylindole
being formed. The use of this reaction as a qualitative estimation of nitrites has been abandoned, due
to a 25% error vh ich could not be detected.
Aliphatic monobasic acids have been identified
by the formation of 2- substituted benziminazole picrates.
The reaction is not quite general, but is exceedingly
useful for those acids soluble in water.
2:4-Dinitrobenzoic acid has been prepared . from phenylacetic acid and fuming nitric acid. The
yield is almost quantitative and the purity good, but
as a reagent for alcohols it is inferior to the
3 :5- dinitrobenzoic acid already in use.