Synthesis of para-Dichlorobenzene by Chlorobenzene Chlorination on NaY Zeolite Heterogeneous Catalyst

A selective procedure for p -dichlorobenzene synthesis, yielding p- dichlorobenzene and 1,2,4-trichlorobenzene free of isomeric dichlorobenzenes, was suggested. The chlorination was performed in two steps: with feeding chlorine in an equimolar amount relative to chlorobenzene in the first step and with feeding a small (1.3–1.5-fold) excess of chlorine in the second step. NaY zeolite with the mean particle size of 3–6 μm was used as the heterogeneous chlorination catalyst. The possibility of regeneration and multiple use of the heterogeneous catalyst was demonstrated.