Physical and Chemical Properties of Amines

Hoffmann Bromamide Degradation Reaction
Best method for removing of carbon:
When amide is treated with Bromine in the presence of strong base gives amine which has 1 carbon less than that of substrate that's why reaction is called degradation reaction

Note:- The above method is useful in various conversions
Toluene — Aniline

PHYSICAL PROPERTIES
Aniline is soluble in dil. HCl because it can form aniline ions.
Amines are in general colorless due to interaction with atm. O₂ they turns to brown colour.
Basic nature of amines:- When amines are treated with an acid forms salts, this inferences the basic nature of

Basic strength can be understood with reference of base dissociation constant k_b or power of base dissociation constant P^kb.
According to kinetics:-
\tt R-NH_{2} + H_{2}O \rightleftharpoons R - NH_{3}^{\oplus} + OH^{\ominus}
\tt K_{equi} = \frac{\left\{R-NH_{3}^{\oplus}\right\}\left\{OH^{-}\right\}}{\left\{R-NH_{2}\right\}\left\{H_{2}O\right\}}
\tt K_{equi} \left\{H_{2}O\right\} = \frac{\left\{R-NH_{3}^{\oplus}\right\}\left\{OH^{-}\right\}}{\left\{R-NH_{2}\right\}}

Higher the k_b, ↑ the basic strength
P^kb = −log k_b
lower the _Pk^b higher the basic nature.

In gaseous phase: -

i.e, NH₃ < 1° < 2° < 3°.

In case of  aq. phase.
Basic strength influenced by following 3 factors:-
Solvation, Inductive effect, Steric effect.

All those three effects makes 2° amine more basic than either 1° or 3°

In case of methylamines :- [Solvation dominates + I]
(CH₃)₂NH > CH₃NH₂ > (CH₃)₃ N > NH₃

In case of ethyl or any other aliphatic amines:-
+I effect dominates solvation.

All aliphatic amines are more basic than ammonia and aromatic amines.
Isomeric amines alicyclic amines are more basic than aliphatic
Since +I effect more in case alicyclic than aliphatic.
In case  of aromatic amines the lone pair of nitrogen is always engaged with aryl group through +R effect as aryl amines are less basic than ammonia.

AFFECT OF GROUP TOWARDS BASIC STRENGTH OF ARYL AMINES

ORTHO EFFECT:
Whether it is e⁻ releasing or withdrawing group present at ortho to NH₄ except (ortho amino phenol) remaining all ortho substituted amines are less basic than aniline.
e^Θ releasing group present at para position increases the e^Θ density on nitrogen and makes it more basic than aniline.
If e^Θ withdrawing group present at para position decreases the e^Θ density on nitrogen makes it less basic than aniline.
The relative basic strength also influenced by inductive effect of corresponding substituent.

In case of ortho amino phenone due to ability to form intramolecular hydrogen bond ortho amino phenone is basic then aniline.

Special Case:

Chemical properties of aniline:

Chemical properties of amides:

Properties of cyanides:

Properties of Nitro compounds:-