Diazonium salts synthesis benzenediazonium ion

Diazonium salts, reactions Coupling to form azo dyes Replacements a) -Br, -Cl, -CN b) -I c) -F d) -OH e) -H f) etc.

coupling to form azo dyes

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

p-bromotoluene

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

m-bromophenol

p-toluic acid

1,2,3-tribromobenzene

1,3,5-tribromobenzene

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

p-ethylaniline d c b a