Stability of B-Zeolite Catalyst in Alkylation

R. B. C. Pillai

Chemistry Department, Indian Institute of Technology, Chennai- 600 036 (India)

Isopropylation of aniline over zeolite produced N-isopropylaniline, ortho and para-isopropylanilines in the temperature range of 200 to 400°C. The activity of the catalyst was steady till sixth cycle of operation each of one hour duration. From seventh hour onwards the activity declined. The XRD, TGA and surface area of the fresh and deactivated catalyst were measured. Blockage of pores and coverage of surface of zeolite by carbonaceous materials and poisoning of active sites by nitrogenous compounds are the presumed causes of deactivation. In a control reaction the isopropyl alcohol over zeolite gives propene which produces coke on polymerization. The coke formed can also contribute to the deactivation of the catalyst. The catalyst was regenerated by heating at 450° for 6 h in a stream of air. The regenerated catalyst showed improved activity.

b-zeolite; Alkylation; N-isopropylaniline