Kinetic vs Thermodynamic Control
when naphthalene is sulphonated two different products are isolated depending on the
reaction conditions used:
naphthalene is more reactive than benzene
it reacts faster in α-position (only two possible sites of attack)
more resonance forms in which the other benzene ring is not disrupted:
these are major contributing canonicals
but for b-attack only 1resonance form which does not destroy the second aromatic
ring is available:
However, a-substitution suffers from periinteraction with the hydrogen atom at C8
SO3H
SO3H
SO3H
SO3H
SO3H
conc. H2SO4