A Manual of the Chemistry of the Carbon Compounds

THE CARBON COMPOUNDS. 83
compound radical is present in most of the organic acids, and the
basicity of an acid depends on the number of times il occurs. Thus
the fatty acids are compounds of carboxyl with monad alcohol
radicals, their general formula being CnIL> + . CO ) n
Hf U -
The group carboxyl is derived from methyl by oxidation :—
OH, CH8 CH,
I Ethane | Ethyl Alcohol j Acetic Acid
CH8 CHj-OH CO.OH
Carhoxyl is also, as we have already seen, easily derived from
cyanogen, which by the action of alkalis takes up water and forms
ammonia and carboxyl:—
CH» CH,
+NHL
CN
CO OH
OQ the other hand, carboxyl can again be reconverted to cyanogen
; by heating ammonium acetate, it decomposes into water and
acetemide:—
CH8 CH8
I » I + HaO
CO.ONH4 CO.NH2
And on distilling acetamide with phosphorus pentoxide another
molecule of water is taken, out and acetonitrile is formed:—
CH. CH.
Ac'---'-'*"*
I -I
JO.NE, UN
By acting on fatty acids with chlorine, substitution take3 place in
the alcohol radical; thus from acetic acid the following three chlorinated
acids ha,ve been obtained •.—
MonocWoracolio Dichlorocotio Triclilomcotic
Acid. AeiJ, Acid.
CH.01 CHW8 OUla
I I I
CO.OH CO.OH CO.OH
In the place of chlorine we may nlso introduce bromine or iodine,
and these elements can again be exchanged by other monad radicals.
By replacing them by alcohol radicals we obtain higher members of
the series of fatty acids-, tlms,by heating iodacetie acid with ethyl
iodide and finely divided silver, butyric acid is formed:—