Edexcel IAL Chemistry A2 19.6 diazonium ions and azo dye coupling
Edexcel IAL Chemistry A2 19.6 diazonium ions and azo dye coupling
Keep the diazotisation cold: sodium nitrite and hydrochloric acid form nitrous acid in situ, then phenol in alkaline solution couples at about 0-5 °C.
How this is tested
- Select NaNO2 and HCl at 0-5 °C to form a benzenediazonium ion from phenylamine.
- Draw the diazonium ion with the positive charge on the correct nitrogen atom.
- Apply alkaline phenol and low temperature conditions for azo dye coupling.