A Manual of the Chemistry of the Carbon Compounds

100 THE CHBMIXTRY OF
On adding sodium to zinc methide, zino separates out, and a
crystalline compound Zn(CH3)2 + NaCHs is formed. It has not
been possible so far to isolate from thi3 compound pure sodium
methide NaCHj. On passing carbonic dioxide over it, it is absorbed,
with evolution of heat and formation of sodium acetate:—
NaCH8 + C02 = NaC2H3O2
Merewrie Methide Hg^Hg)^—Methyl iodide is not acted upon by
liquid sodium amalgam, but on adding a small quantity of acetic
ether, a brisk reaction set in, sodium iodide and mercury methide
being formed. It is not understood what part the acetic ether plays
in this reaction, as it remains unaltered.
Mercuric methide is a heavy colourless liquid with a peculiar though
not an unpleasant smell. It is most poisonous, is not acted upon by
the air, and boils at 95°,
METHANE AND ITS SUBSTITCHON PRODUCTS.
Methane, Methyl Hydride, CH4.—This gas occurs in nature, being
always formed when vegetable matters decay in the absence of air.
It ia found in coal mines (firedamp), and in marshes and stagnant
waters (marsh-gas), and in many districts it is evolved from the
soil, as in Baku on the Caspian Sea, where the holy fires have been
burning from time immemorial. Although the most simple of all
hydrocarbons, it cannot be produced by direct combination of carbon
and hydrogen, but is formed by passing hydrogen sulphide, mixed
with the vapour of carbon disulphide, over red-hot copper;—
CSa + 2SHa + 4Cua = CH4 + 4CuaS
Pure methane is obtained by the action of water upon zinc methyl,
but a readier method to prepare it is to heat a mixture of dry sodium
acetate with twice its weight of soda lime;—
Methane is a colourless, inodorous gas, which burns with a pale
flame. It has not yet been oondensed to a liquid by the strongest pressure
or cold. With ten volumes of air or with two volumes of oxygen
it forms a mixture, which on applying a light ignites with a violent
explosion. By exposing a mixture of equal volumes of marsh-gas and
chlorine to direct sunlight an explosion takes place, with the separation
of carbon; but in diffused light the action goes on more gently,
the principal product being methyl chloride, and if an excess of
chlorine is present higher chlorinated substitution products are
formed, These bodies are generally regarded as compounds of dyad