Dear
AhmedEzatAlzawalaty;
I don’t know
HOW high with temperature you have to “go" to get the para isomer predominant, because normally the para isomer is predominant if you use
Potassium Phenolate instead of
Sodium Phenolate.
The Sodium “seems” to have just the
correct size to form the “required”
Intermediate-Complex which finally results in the ortho isomer as several German literatures are telling:
Example: "
Chemgapedia.de”
But with Potassium with its different size the “normal” Substitution-Rules for
Benzene is followed.
(Also from several German literatures.)
Good Luck!
ARGOS
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