S. Sharma et al., A NOVEL AND DIRECT SELECTIVE IODINATION OF TOLUENE TO PARA-IODOTOLUENE USING ZEOLITE CATALYSTS, Catalysis letters, 40(3-4), 1996, pp. 257-260
A new and direct procedure for the selective formation of para-iodotol
uene from toluene is demonstrated for the first time using iodine mono
chloride (ICl) as the iodinating agent and zeolite H-beta as the catal
yst. Zeolite H-beta and H.K-L are found to be more para-selective comp
ared to other zeolite catalysts and the conventional catalysts, H2SO4
and SiO2. In the presence of a solvent (nitrobenzene) the conversion o
f ICl increases and the formation of side products (chlorotoluenes) de
creases. The probable mechanism for the formation of iodotoluenes and
some amount of chlorotoluenes involves the electrophilic attack of tol
uene by I+ and CL(+), respectively.