A Manual of the Chemistry of the Carbon Compounds

THE CARBON COMPOUNDS. 71
"When chlorine is passed into a liquid paraffin, a portion of the
monochloride first formed is always further acted upon by chlorine
before all the hydrocarbon has been attacked, but the formation of
such higher chlorides caa be almost completely avoided, when chlorine
is brought in contact with the vapour of the boiling hydrocarbon ;
the monochlorides being less volatile condense at once, and thus are
brought out of the reach of an excess of chlorine.
Bromine acts on the paraffins in a manner similar to that of
chlorine, only much less energetically, whilst iodine has uo action
whatever.
The monochlorides can by double decompositions easily be transformed
into the alcohols and other derivatives. Thus on heating
methyl chloride with caustic potash we obtain methyl alcohol :—
CH8C1 + KOH « C1K + CH8.OH
By heating the chlorides with concentrated hydriodic acid, the
iodides are formed; which compounds are also obtained by acting
upon alcohols with hydriodic acid. Thus amyl alcohol yields aniyl
iodide :—
C5HU.OH + HI = C6HnI + H2O
On the other hand these derivatives of the paraffins can agaiu be
transformed into the original hydrocarbons. Thus by treating the
substitution products of marsh-gas with zinc and hydrochloric acid,
an invem substitution takes place, hydrogen again replacing one atom
of chlorine after the other:—-
CC14 H|-
II2 : = CH Cl8 HhHCl
CH Cl8 -t"
Ho = CH2C12 HhHCl
CHoCL -t-H2
= CH8C1 AI-HC1
CH3C1 • ~ CH, HhHCl
The iodide3 are even more easily reduced by the same reaction,
and thus from any alcohol the corresponding paraffin may be obtained,
The alcohols of dyad, triad, tetrad, and hexad radicals can also bo
converted into paraffins, inasmuch as these bodies arc readily trans*
formed into iodides of monad radicals by the action of hydriodic acid.
Thus mannite C6H8(OH)8 yields hexyl iodide:—
C8H8(0H)0 + 11HI = C6H,SI + 6H8O + 5I8
And this iodide is transformed by nascent hydrogen into hexane:—
COH1SI + H, = C0HM + HI
Instead of acting on the iodides with nascent hydrogen they may
l)e heated with zinc and water in sealed tubes to 150°, when basic
zinc iodide and a paraffin are formed:—
CjH^ + H2O + Zu = C6HK + Zn { ou
The paraffins obtained from the iodides by these two methods