the process for the separation of isomeric dichlorotoluenes , comprising the steps of : passing a mixture containing isomeric dichlorotoluenes over a zeolite of the zsm5 type having the composition of m 2 / n o : al 2 o 3 : sio 2 : z h 2 o in which m is at least one cation selected from h , an alkali metal , an alkaline earth metal or a tetraalkylammonium cation ; n is the valency of m ; and z is between 0 and 40 : separating the non - adsorbed dichlorotoluenes ; contacting the zeolite containing the adsorbed isomers with an eluent ; and separating the isomers from the eluent .