Chemistry Reference
In-Depth Information
AMINES
NH
3
CH
3
NH
2
(CH
3
)
2
NH
(CH
3
)
3
N
ammonia
methylamine
dimethylamine
trimethylamine
(primary)
(secondary)
(tertiary)
Amines are basic and form salts with acids
CH
3
NH
4
Cl
methylamine hydrochloride
CH
3
NH
2
+ HC l
Tertiary amines react with alkyl halides to form
quaternary ammonium salts
(CH
3
)
4
N
+
Br
-
tetramethylammonium bromide
+
(CH
3
)
3
N
CH
3
Br
Organic derivatives of ammonia are called amines. Because nitrogen is
trivalent, amines can be primary (attached to one carbon), secondary
(attached to two carbons), or tertiary. All amines are basic, and their strength
as bases increases with the number of alkyl groups attached to the nitrogen;
that is, methyl amine is a stronger base than ammonia and trimethylamine
is stronger than dimethylamine. Amines can be prepared from ammonia and
an alkyl halide:
C
2
H
5
Br
+
NH
3
C
2
H
5
NH
3
Br
NaOH
C
2
H
5
NH
2
+
NaBr
+
H
2
O
The alkyl halide (ethyl bromide in the above equation) can react further
with the primary amine produced to give a secondary amine and with that
to form a tertiary amine and finally a quaternary ammonium salt. Quater-
nary ammonium hydroxides are very strong bases like sodium hydroxide.
Tetramethylammonium hydroxide is a very important chemical used in the
manufacture of semiconductors and other electronic industry products.
