Isopropylation of benzene with 2-chloropropane on high-temperature chlorine-treated alumina catalyst

On the alumina catalyst, AmLSA, treated with dry chlorine at 573-1173 K, is opropylation of benzene with 2-chloro-propane (2CP) was carried out at 273 K using a semi-batch reactor in which the catalyst was suspended in benzene . AmLSA catalysts showed high activities for isopropylation of benzene and isopropylbenzene. The products were isopropylbenzene (IPB), ortho-, meta-, and para-di-isopropylbenzenes (di-IPB), and 1,2,4- and 1,3,5-tri-isopropylb enzenes (tri-IPB). Formation of tetra-isopropylbenzenes was negligibly smal l. A typical product composition at 2CP conversion 100% was 76, 19, and 5% for IPB, di-IPB, and tri-IPB, respectively, while for isopropylation of IPB , di-IPB and tri-IPB were 82 and 18%, respectively. Pyridine adsorption com pletely poisoned the AmLSA catalyst and even after out-gassing at 873 K, th e original activity was not restored. Since the reactions were completely s topped by removal of the catalyst from the reaction system, it was conclude d that no active species was not dissolved into the organic phase. From the above results and from both results of alkylation of benzene with 1-chloro propane (1CP) and isopropylation using an aluminium trichloride catalyst, i t is explainable that reactions on AmLSA catalysts proceed by a Friedel-Cra ft type mechanism.