- Derivatives of ammonia where the H's are replaced by C chains.
- The number of H's replaced corresponds to the structure, primary = 1 H replaced.
- Often described as having unpleasant odours.
- -amine is the suffix used.
- Amines are weak bases, a proton acceptor, this is due to the lone pair of e- on the N atom, which can accept a proton and form a dative covalent bond.~
- Thus they will react with acids to form salts, an alkylammonium salt:
-CH3CH2NH2 + HCl -> CH3CH2NH3+Cl-
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- Preparing aliphatic primary amines:
-By warming halogenoalkanes with excess ammonia, with an ethanol solvent.
-CH3CH2CH2Cl + NH3 -> CH3CH2CH2NH2 + HCl
-Further ammonia forms: NH3 + HCl -> NH4+Cl-
-To prepare a primary amine, excess ammonia is used to stop further substitution from occuring.
- Preparing aromatic amines:
-Nitrobenzene can be reacted with conc. HCl and tin under reflux; and then neutralisation of the excess HCl.
- Synthesis of dyes:
-Diazotisation: where phenylamine and nitrous acid is kept below 10 degrees C, a diazonium salt is formed.
(Nitrous acid, HNO2, is formed with NaNO2 and HCl)
-This salt then mixes with phenol (etc.) under alkaline conditions (NaOH) and then the coupling of these rings occurs; linked by an azo group -N=N-.
-This brightly coloured mixture formed is a dye.
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