See also:hydrocarbons . It occurs as a constituent of the "
See also:damp " of
See also:coal-mines, in the gases evolved from volcanoes, and in the gases which arise in marshy districts (due to the decomposition of
See also:matter under the
See also:surface of
See also:water) . It is found associated with petroleum and also in human intestinal gases . It is a product of the destructive
See also:distillation of complex organic matter (
See also:wood, coal, bituminous shale, &c.), forming in this way from 3o to 40% of ordinary
See also:gas . It may be, synthetically obtained by passing a mixture of the vapour of
See also:carbon bisulphide with sulphuretted hydrogen over red-hot copper (M . Berthelot, Comptes rendus, 1856, 43, p . 236), CS2 + 2H2S + 8Cu = 4Cu2S +
See also:CH4; by passing a mixture of hydrogen and carbon monoxide over reduced nickel at 200—250° C., or hydrogen and carbon dioxide at 230—300° C . (P .
See also:Sabatier and J . B . Senderens, Comptes rendus, 1902, 134, pp . 514, 689); by the decomposition of aluminium
See also:carbide with water [H .
See also:Moissan, Bull .
See also:Soc . Chim., 1894, (3) II, p . 1012]; and by
See also:heating phosphonium iodide with carbon bisulphide in a sealed
See also:tube to 120-140 C . (H . Jahn, Ber., 1880, 13, p . 127) . It is also obtained by the reduction of many methyl compounds with nascent hydrogen; thus methyl iodide dissolved in methyl
See also:alcohol readily yields methane when acted on by the
See also:zinc-copper couple (J . H . Gladstone and A . Tribe, Jour . Chem .
Soc., 1884, 45, p . 156) or by the aluminium-mercury couple . It may be obtained in an indirect manner from methyl iodide by conversion of this compound into zinc methyl, or into magnesium methyl iodide (formed by the
See also:action of magnesium on methyl iodide dissolved in anhydrous
See also:ether), and decomposing these latter substances with water (E .
See also:Frankland, 1856; V . Grignard, 1900), Zn(
See also:H2O=2CH4+ZnO; 2CH3MgI +H2O=2CH4+MgI2+ MgO . In the laboratory it is usually prepared by J . B . A .
See also:Dumas' method (
See also:Ann., 1840, 33, p . 181), which consists in heating an-hydrous sodium acetate with soda lime, CH3CO2Na + NaOH= Na2CO3 + CH4 . The product obtained by this method is not pure, containing generally more or less
See also:ethylene and hydrogen . Methane is a colourless gas of specific gravity 0.559 (air = I) .
It may be condensed to a colourless liquid at -155° to -16o° C. under atmospheric pressure (S . Wroblewsky, Comptes rendus, 1884, 99, p . 136) . It boils at -162° C. and freezes at -186°C . Itscritical temperature is -99.5° C . (J .
See also:Dewar) . The gas is almost insoluble in water, but is slightly soluble in alcohol . It decomposes into its constituents when passed through a red-hot tube, small quantities of other hydrocarbons (ethane, ethylene,
See also:benzene, &c.) being formed at the same
See also:time . It burns with a
See also:pale flame, and when mixed with air or
See also:oxygen forms a highly explosive mixture . W . A .
See also:Bone (Jour . Chem . Soc., 1902, 81, p . 535; 1903, 83, p . 1074) has shown that in the oxidation of methane by oxygen at 450—500° C. formaldehyde (or possibly methyl alcohol) is formed as an intermediate product, and is ultimately oxidized to carbon dioxide . Methane is an exceedingly
See also:stable gas, being unaffected by the action of chromic acid, nitric acid, or a mixture of nitric and sulphuric acids . Chlorine and bromine, however, react with methane, gradually replacing hydrogen and forming chlor- and brom- substitution products .
MARSH (O. F. mersc, for merisc, a place full of "me...
ADAM MARSH (ADAM DE MARISCO) (d. c. 1258)
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