![]() |
Useful Concepts | ![]() |
Substitution versus Elimination
Substitution and elimination reactions are
strongly influenced by many
factors. Some of the more important factors are outlined in the
following
table.
The significance of the effect is stated first, then the "system" that
will favour the particular reaction is stated.
This should help you deal with the
questions....
1. When does an anion function as a Nu and when does it
function
as a B ?
and therefore,
2. When to I get substitution and when do I get elimination ?
|
|
|
|
|
Typical Conditions |
|
Polar solvents |
Good Nu and weak base |
Good LG |
3o or resonance stabilised |
AgNO3 / aq. EtOH |
|
Polar aprotic solvents |
Good Nu and weak base |
Good LG |
Methyl or 1o |
NaI / Acetone |
|
Polar solvents |
Weak base |
Good LG |
3o or resonance stabilised |
H2SO4, heat |
|
Polar aprotic solvents |
Poor Nu and strong base |
Good LG |
3o |
KOH, heat, |
![]() |
© Dr. Ian Hunt, Department of Chemistry, University of Calgary | ![]() |
�$�gA�9�]�,�q�dYZ���c.·;�����%�U�5Quf���vi[�����¾���"#���f&F�Π�X|�#��엕h�J����ѣ�?������Ҷ��jm��{�*�~�Q��4�xZ���� h�/[/>��z�Key5YA� }Af�ɉ�モ��i_8M���R:1�r�#M�ćV�$l�0)2�WA���0|_ٳ)�ǽ�gK�^?ӜfX���/�HZ T[�]>���Oϔ.i"R�3uH?�:ϼ3�5N[�6�I9���w�\_�"T|�]:�#/���5�l���ێ�R*������N*�AT���-->