A Manual of the Chemistry of the Carbon Compounds

184 THE CHBMHTRY OF
CO.OH CO.OH
CH2
CH2
CH2I CH2
+ Ag2=| +2AgI
CH2I CH2
CH2
CHg
CO.OH CO.OH
By the same reaction, ft lyromjnopionic acid is converted into
dimethylsmxinic add,:—
CO.OH
I CO.OH
CH.CH8 |
Br CH.CH8
8
Br
+ Ag, =
CH.CH.
I + 2AgI
CH.CH
CHCH3
I CO.OH
CO.OH
Many of the aoids belonging to this group are formed by the
oxidation of fats and other bodies. Three of them ocour in nature,
viz. oxalic acid, succinic acid, and rooellic aoid.
KTHENE COMPOUNDS.
ETUEHE CgH4.
This hydrocarbon is'formed, together with many other products,
by the destructive distillation of organic bodies, as fats, resins,
wood, coal, &c. To obtain pure ethene a mixture of one volume of
strong alcohol and 3—4 volumes of concentrated sulphuric acid is
gently heated, and the gas washed with concentrated sulphuric acid
and a solution of caustic soda, in order to free it from the vapours
of alcohol and ether, and from carbon dioxide and sulphur dioxide,
which two gases are always formed towards the eud of tho reaction.
Ethene ia a colourless gas having a pecnliat 1 faint and snffocating
odour. It condenses at — 1-10° to a liquid; it is very inflammable,
burning with a hright luminous flame.
It was formerly called olcfiantgas, because it combines with chlorine
to form ethene dichloride, an oily liquid. Ethene also combines
readily with bromine, but more difficultly with iodine. The concen-