A Manual of the Chemistry of the Carbon Compounds

TEE OAKBON COMPOUNDS. 175
COMPOUNDS OF DYAD RADICALS.
DYAD ALCOHOL-RADICALS.
By depriving the paraffins of two atoms of hydrogen a aeries of
hydrocarbons ia obtained having the general formula CH^, to which
the name the Okfiries has been given (from olefiaut gas, an old name
of ethene, the first hydrocarbon of the series). The names of the
defines are derived from those of the paraffins by changing the final
•ane into -em:—
Ethane . . C2H8 Ethene . . CjH«
Propane . . C3H8
Propene . . C,H6
A general method of obtaining defines consists in the abstraction
of the elements of water from the monad alcohols. This may be
effected by means of sulphuric acid, zinc chloride, and other dehydrating
agents:—
C2H80 - H,0 = C2H4
C6H120 - H8O = C6H10
Olefines are also produced by heating the haloid compounds of
monad alcohol radicals with a solution of caustic potash in spirits
of wine:—
C8H13C1 + KOH = C0H12 + H2O + KC1
Of other reactions by which olefines are formed the following may
be mentioned.
By 'acting on the iodides of the monad alcohol radicals with
nascent hydrogen, or with sodium or zinc, not only are paraffins
formed, but also defines in smaller quantities. Thus when ethyl
iodide is heated with zinc, not only is butane formed but also ethane
and cthene .'—
2C2H5I + Zn = C2H9
By the action of zinc and hydrochloric acid upon secondary hexyl
iodide, hexane CgHu is formed as the chief product, but at the same
time some hcxenc O,,H12 and some dihexyl 0uHm are produced:—
(1) OfiJ + H4 = C,HM + IK
(2) 2CaHwI + Zn = C,HM + C^H^ + Znl2
(3) 2Q,HuI+Zn«CISHw + ZiiI,
' Formerly they wore designated by numes derived from those of tho mound alcohol
livlicalsby tue addition ol -eiic .• thusotln:ue is s\\H frequently calleJ etliyl«ip, tc.