Chemistry Reference
In-Depth Information
Cl
Br
δ
_
δ
_
δ
+
δ
+
Cl
Br
Fe
Br
Cl
2
+FeBr
3
Cl
Cl
Fe
Br
Br
Br
Br
δ
_
δ
+
Br
Cl
Fe
Cl
FeBr
2
Cl
+
Cl
Br
Br
In this way, electrophilic bromine (Br
+
) could be formed. Consequently, a mixture of
chlorinated and brominated aromatic products would be obtained.
4.35
D
2
SO
4
is a strong acid and a source of the electrophile D
+
(analogous to H
+
from
H
2
SO
4
).
D
H
HD
+D
+
+H
+
+
Loss of H
+
from the intermediate benzenonium results in replacement of H by D.
With a large excess of D
2
SO
4
, these equilibria are shifted to the right, eventually
resulting in fully deuterated benzene, C
6
D
6
.
The carbon bonded to the electrophile (E) is
sp
3
-hybridized. The remaining carbons
are
sp
2
-hybridized.
4.36
H
+
E
4.37
a.
Meta
-directing and ring-deactivating because of the positive charge on the
nitrogen (electron-withdrawing).
+
NH(CH
3
)
2
b.
Meta
-directing and ring-deactivating because of the partial positive charge on
the carbonyl carbo
n,
due to contributors such as
c.
Ortho
,
para
-directing and ring-activating because of the unshared electron
pairs on the sulfur.
S
CH
3
