is employed for dissolving ionic com-
pounds when water cannot be used.
ethanoate(acetate)A salt or ester
of ethanoic acid (acetic acid).
ethanoic acid (acetic acid)A clear
viscous liquid or glassy solid car-
boxylic acid, CH 3 COOH, with a char-
acteristically sharp odour of vinegar;
r.d. 1.049; m.p. 16.6°C; b.p. 117.9°C.
The pure compound is called glacial
ethanoic acid. It is manufactured by
the oxidation of ethanol or by the ox-
idation of butane in the presence of
dissolved manganese(II) or cobalt(II)
ethanoates at 200°C, and is used in
making ethanoic anhydride for pro-
ducing cellulose ethanoates. It is also
used in making ethenyl ethanoate
(for polyvinylacetate). The compound
is formed by the fermentation of al-
cohol and is present in vinegar,
which is made by fermenting beer or
wine. ‘Vinegar’ made from ethanoic
acid with added colouring matter is
called ‘nonbrewed condiment’. In liv-
ing organisms it combines with co-
enzyme A to form acetyl coenzyme
A, which plays a crucial role in en-
ergy metabolism.
ethanoic anhydride (acetic anhy-
dride)A pungent-smelling colourless
liquid, (CH 3 CO) 2 O, b.p. 139.5°C. It is
used in organic synthesis as an
*ethanoylating agent (attacking an
–OH or –NH group) and in the manu-
facture of aspirin and cellulose plas-
tics. It hydrolyses in water to give
ethanoic acid.
ethanol(ethyl alcohol)A colourless
water-soluble *alcohol, C 2 H 5 OH; r.d.
0.789 (0°C); m.p. –117.3°C; b.p.
–78.3°C. It is the active principle in
intoxicating drinks, in which it is
produced by fermentation of sugar
using yeast
C 6 H 12 O 6 →2C 2 H 5 OH + 2CO 2The ethanol produced kills the yeast
and fermentation alone cannot pro-
duce ethanol solutions containing
more than 15% ethanol by volume.
Distillation can produce a constant-
boiling mixture containing 95.6%
ethanol and 4.4% water. Pure ethanol
(absolute alcohol) is made by remov-
ing this water by means of drying
agents.
The main industrial use of ethanol
is as a solvent although at one time it
was a major starting point for mak-
ing other chemicals. For this it was
produced by fermentation of mo-
lasses. Now ethene has replaced
ethanol as a raw material and indus-
trial ethanol is made by hydrolysis of
ethene.
ethanolamineAny of three low-
melting hygroscopic colourless
solids. They are strong bases, smell of
ammonia, and absorb water readily
to form viscous liquids. Mono-
ethanolamine, HOCH 2 CH 2 NH 2 , is a
primary *amine, m.p. 10.5°C; di-
ethanolamine, (HOCH 2 CH 2 ) 2 NH, is a
secondary amine, m.p. 28°C; and tri-
ethanolamine, (HOCH 2 CH 2 ) 3 N, is a
tertiary amine, m.p. 21°C. All are
made by heating ethylene oxide with
concentrated aqueous ammonia
under pressure and separating the
products by fractional distillation.
With fatty acids they form neutral
soaps, used as emulsifying agents
and detergents, and in bactericides
and cosmetics.
ethanoylating agent (acetylating
agent)A chemical reagent used to
introduce an ethanoyl group
(–COCH 3 ) instead of hydrogen in an
organic compound. Examples include
*ethanoic anhydride and ethanoyl
chloride (acetyl chloride, CH 3 COCl).
ethanoyl chloride (acetyl chloride)
A colourless liquid acyl chloride (see
acyl halides), CH 3 COCl, with a pun-
gent smell; r.d. 1.105; m.p. –112.15°C;
b.p. 50.9°C. It is made by reacting
ethanoic acid with a halogenating213 ethanoyl chloride
e