Question

How to convert Toulene to 2chlorotoulene

Answer 1

1. A continuous process for preparing m-chlorotoluene which comprises the steps of:

(a) chlorinating toluene to form a toluene chlorination product rich in o-chlorotoluene;

(b) neutralizing the chlorination product and separating-off by distillation unreacted toluene and higher chlorinated by-products to obtain a purified toluene chlorination product rich in o-chlorotoluene;

(c) treating the purified toluene chlorination product with an isomerization catalyst comprising a zeolite of the pentasil type to form an isomerization product with increased content of m-chlorotoluene;

(d) isolating p-chlorotoluene from the isomerization product by selective adsorption of p-chlorotoluene onto a mesoporous or macroporous Y zeolite K+ or Ba2+ exchanged and subsequent desorption of p-chlorotoluene to obtain desorbed p-chlorotoluene and an unadsorbed phase lean in p-chlorotoluene and rich in o- and m-chlorotoluene;

(e) recycling the desorbed p-chlorotoluene to step (c);

(f) separating the unadsorbed phase by distillation or adsorption into o- and m-chlorotoluene;

(g) removing the separated m-chlorotoluene; and

(h) recycling the o-chlorotoluene to step (c).

2. A continuous process for preparing p-chlorotoluene which comprises the steps of:

(a) chlorinating toluene to form a toluene chlorination product rich in o-chlorotoluene;

(b) neutralizating the chlorination product and separating-off by distillation unreacted toluene and higher chlorinated by-products to obtain a purified toluene chlorination product rich in o-chlorotoluene;

(c) isolating p-chlorotoluene from the purified toluene chlorination product, by selective adsorption of p-chlorotoluene onto a mesoporous or macroporous Y zeolite K+ or Ba2+ exchanged and subsequent desorption of p-chlorotoluene to obtain an unadsorbed phase lean in p-chlorotoluene and rich in o-chlorotoluene;

(d) removing the desorbed p-chlorotoluene;

(e) treating the unadsorbed phase with an isomerization catalyst comprising a zeolite of the pentasil type to form an isomerization mixture with increased content of m- and p-chlorotoluene; and

(f) recycling said isomerization mixture to step (c).