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Reactions of Amines - Coggle Diagram
Reactions of Amines
-
-
Basic Character
alkyl groups in amine = Electron Donating
- increase electron density around N
EXPLANATIONS
amines stronger than ammonia
- basicity increases w size of alkyl group
- larger alkyl group = more electron donating
- electrons pushed towards N
- ∴ lone pair of e- more available to accept a H+
effect largely cancelled out for larger amines
- less soluble in water
- ∴ weaker bases anyways
phenylamine weaker than ammonia
- lone pair on N
- involved in π bonded ring
- ∴ less available to accept H+
- (aromatic ring = electron withdrawing effect)
overall order of basic strengths
(most to least)
- 3° aliphatic amine
- 2° amine
- 1° amine
- ammonia
- phenylamine (1° aromatic amine)
- amides
-
-
With Nitrous Acid (HNO2)
-
nitrous acid/nitric (III) acid
- unstable
- pale blue colour in solution
generated in situ
solution of:
- sodium nitrite (NaNO2)
- in HCl
- in cold (5°C)
unless kept cold:
- will decompose quickly
- releasing brown fumes of NO2
Ethylamine
-
products
- N2 (colourless, odourless gas)
- ethanol
- water
observations
- loss of blue colour
- bubble of colourless gas
-
-
Phenylamine
conditions
- cold (5°C)
- in presence of HCl
- addition of sodium nitrite solution
BELOW 5°C
products
- benzene diazonium chloride
(benzene diazonium ion stabilised by
presence of benezne ring
- +ve charge spread around delocalised e- in ring)
ABOVE 5°C
- benzene diazonium ion
decomposes to form
- PHENOL
observations
- bubbles of colourless gas
- characteristic phenol smell detected
method
- miz 2cm3 of water with 2cm3 of conc HCl
- cool in ice bath
- add 5 drops ethylamine/phenylamine
- cool after each drop
- add drops of conc. sodium nitrite solution
- cool after each drop