methanationA method of manu-
facturing methane from carbon
monoxide or dioxide by high-
pressure catalytic hydrogenation.
It is often used to improve the
caloriÜc value of town gas.methaneA colourless odourless
gas, CH 4 ; m.p. –182.5°C; b.p. –164°C.
Methane is the simplest hydrocar-
bon, being theÜrst member of the
*alkane series. It is the main con-
stituent of natural gas (∼99%) and as
such is an important raw material for
producing other organic compounds.
It can be converted into methanol by
catalytic oxidation.
methanideSee carbide.methanoate(formate)A salt or
ester of methanoic acid.methanoic acid (formic acid)A
colourless pungent liquid, HCOOH;
r.d. 1.2; m.p. 8°C; b.p. 101°C. It can be
made by the action of concentrated
sulphuric acid on the sodium salt
(sodium methanoate), and occurs nat-
urally in ants and stinging nettles.
Methanoic acid is the simplest of the
*carboxylic acids.methanol(methyl alcohol)A
colourless liquid, CH 3 OH; r.d. 0.79;
m.p. –93.9°C; b.p. 64.96°C. It is made
by catalytic oxidation of methane
(from natural gas) using air.
Methanol is used as a solvent (see
methylated spirits) and as a raw
material for making methanal
(mainly for urea–formaldehyde
resins). It was formerly made by the
dry distillation of wood (hence the
name wood alcohol).
methionineSee amino acid.methoxy group The organic
group CH 3 O–.methyl acetateSee methyl
ethanoate.methyl alcoholSee methanol.methylamineA colourlessÛamma-
ble gas, CH 3 NH 2 ; m.p. –93.5°C; b.p.
–6.3°C. It can be made by a catalytic
reaction between methanol and am-
monia and is used in the manufac-
ture of other organic chemicals.methylated spiritsA mixture
consisting mainly of ethanol with
added methanol (∼9.5%), pyridine
(∼0.5%), and blue dye. The additives
are included to make the ethanol un-
drinkable so that it can be sold with-
out excise duty for use as a solvent
and a fuel (for small spirit stoves).methylationA chemical reaction
in which a methyl group (CH 3 –) is in-
troduced in a molecule. A particular
example is the replacement of a hy-
drogen atom by a methyl group, as in
a *Friedel–Crafts reaction.methylbenzene(toluene)A
colourless liquid, CH 3 C 6 H 5 ; r.d. 0.9;
m.p. –95°C; b.p. 111°C. Methylben-
zene is derived from benzene by re-
placement of a hydrogen atom by a
methyl group. It can be obtained
from coal tar or made from methyl-
cyclohexane (extracted from crude
oil) by catalytic dehydrogenation. Its
main uses are as a solvent and as a
raw material for producing TNT.methyl bromide See bro-
momethane.2-methylbuta-1,3-dieneSee iso-
prene.
methyl chlorideSee
chloromethane.methyl cyanideSee ethane-
nitrile.methyleneThe highly reactive
*carbene, :CH 2. The divalent CH 2
group in a compound is the methyl-
ene group.methylene chlorideSee
dichloromethane.methanation 352m