Enhanced p-selectivity from separation of the mixture containing p-chloronitrobenzene and o-chloronitrobenzene with Sb2O3 modified HZSM-5 zeolite

Abstract

HZSM-5 zeolite was modified with Sb2O3 powder, and p-selectivity from separation of the mixture containing p-chloronitrobenzene (p-CNB) and o-chloronitrobenzene (o-CNB) in modified HZSM-5 zeolite was simultaneously studied. It can be observed that Sb2O3 was mainly dispersed on external surface of HZSM-5 zeolite, which might finely narrow pore opening of the zeolite. The maximum adsorption amount of p-CNB in the modified zeolite was about 4 molecules per unit cell, which was larger compared to that of o-CNB. In addition, the diffusion coefficient of p-CNB in Sb2O3 modified HZSM-5 at 300 K is observed to be about 531 times higher than that of o-CNB. Compared to 85 % p-CNB purity recovered from parent HZSM-5 zeolite, the more remarkable differences in adsorption capacity and diffusivity between p-CNB and o-CNB in Sb2O3 modified HZSM-5 led to a higher p-CNB purity of 98.4 %, which indicates that p-selectivity of HZSM-5 zeolite was significantly enhanced through the modification with Sb2O3 powder.