Transcript Document
Diazonium salts
synthesis
HNO3
NO2
H2SO4
H2, Ni
HONO
N N
benzenediazonium ion
NH2
Diazonium salts, reactions
1. Coupling to form azo dyes
2. Replacements
a) -Br, -Cl, -CN
b) -I
c) -F
d) -OH
e) -H
f) etc.
coupling to form azo dyes
N2
G
G
+
an azo dye
G = OH, NH2,
NHR, NR2, etc.
CH3
H3C N
N N
+
N,N-dimethylaniline
N2
SO3H
CH3
H3C N
N N
methyl orange
SO3H
Sandmeyer
Ar-N2+ + CuCl Ar-Cl + N2
Ar-N2+ + CuBr Ar-Br + N2
Ar-N2+ + CuCN Ar-CN + N2
Ar-N2+ + KI Ar-I + N2
Ar-N2+ + HBF4 Ar-F + N2
Ar-N2+ + H2O, H+ Ar-OH + N2
Ar-N2+ + H3PO2 Ar-H + N2
Cl
Br
CN
I
F
H3PO2
NH2
H2O,H+
HBF4
KI
CuCN
CuBr
CuCl
NO2
N2
OH
Br
NaCN
NR
NO2
HNO3
NH2
H2/Ni
H2SO4
NaNO2
HCl
C N
benzonitrile
N2
CuCN
I2, Fe
NR
NO2
NH2
H2/Ni
HNO3
H2SO4
NaNO2
HCl
I
iodobenzene
N2
KI
Br
NaOH
NR
NO2
NH2
H2/Ni
HNO3
H2SO4
NaNO2
HCl
OH
phenol
N2
H2O,H+
p-bromotoluene
CH3
CH3
CH3
Br
Br2,Fe
+
Br
bp 185oC
bp 182oC
You cannot separate a mixture of ortho and parabromotoluene in a reasonable purity. Their bp's are
too close together!
CH3
CH3
CH3
HNO3
H2SO4
+ ortho-
H2/Ni
bp 222oC
NH2
NO2
bp 238oC
A mixture of ortho & paranitrotoluenes is separable in
a reasonable yield and purity
NaNO2
HCl
CH3
CH3
CuBr
Br
N2
In syntheses, you may no longer assume that you can
separate a pure para isomer from an ortho/para
mixture. Either look up the physical properties of
the compounds or rely on experience gained in the
homework as to which mixtures are separable and
which ones are not!
m-bromotoluene
CH3
CH3
CH3
HNO3
H2SO4
+ ortho-
H2/Ni
bp 222oC
NH2
NO2
bp 238oC
(CH3CO)2O
CH3
CH3
CH3
H2O,OH-
Br
NH2
Br2,Fe
Br
NHCOCH3
NHCOCH3
CH3
CH3
H3PO2
HONO
Br
N2
Br
m-bromophenol
NO2
NO2
HNO3
H2SO4
Br2,Fe
Br
H2/Pt
OH
NH2
N2
Br
H2O
NaNO2
H+
H+
Br
Br
p-toluic acid
CH3
CH3
CH3
HNO3
H2SO4
+ ortho-
H2/Ni
bp 222oC
NH2
NO2
bp 238oC
CH3
NaNO2
HCl
CH3
H2O, H+
CH3
CuCN
heat
COOH
CN
N2
1,2,3-tribromobenzene
NO2
(CH3CO)2O
H2/Ni
HNO3
NHCOCH3
NH2
H2SO4
HNO3
H2SO4
TAR!
NH2
Br
NH2
Br
NHCOCH3
Br2 (aq)
H2O, OH-
+ ortho-
heat
NO2
NO2
NO2
HONO
H3PO2
Br
N2
Br
Br
CuBr
Br
Br
Br
H2
Br
Br
Ni
NO2
NO2
Br
Br
HONO
H3PO2
NH2
Br
1,3,5-tribromobenzene
NH2
NO2
H2/Ni
HNO3
H2SO4
Br2 (aq)
polybromination
N2
Br
Br
Br
H3PO2
Br
Br
Br
NH2
HONO
Br
Br
Br
Spectroscopy of amines
Infrared:
N—H stretch 3200 – 3500 cm-1
1o often two bands
2o one band
3o no bands
N—H bend
1o strong bands 650-900 cm-1(broad) and 1560-1650 cm-1
nmr: N—H 1-5 ppm (often broad and low)
p-toluidine
N—H
stretch
N—H bend
NH2 c
p-ethylaniline
d
CH2CH3
b a
d
c
b
a