Question

When toluene reacts with Cl_2, the identity of the major product(s) obtained depends on the reaction is carried out in the presence of catalytic amounts of Fecl_3 or without catalyst at high temp. Explain clearly.

Answer 1

FeCL4 CI CI Cl CI CI In sandmayer reaction occurred via Lewis acid because of the Lewis acid will generates the chlornium ion (electrophile) the more nucleophile centre easily attack on these type of electrophile very easily. The Electrophilic substitution takes places on benzene very easily through Lewis acid which should decreases the nucleophilicity on chlorine gas. Without Lewis acid in presence of High temp only allylic substitution takes if the benzene substituted with methyl group but the chlorine should not substituted anywhere other than SP3 carbon atom. i.e. allylic carbon in presence of High Temp