Role of Solid Acid Catalyst in Isopropylation Reaction

Abstract

Cumene synthesis was carried out by the reaction of benzene with isopropyl alcohol in the vapour phase over rare earth metal modified 13X zeolite. Zeolite modification was done by exchanging sodium ions of the zeolite with cerium ions to vary the acidity of the catalyst in the range of 0.25‑1.36 meq/g. The synthesis was carried out over a wide range of operating conditions. The synthesis conditions were optimized by studying the effects of various process parameters, viz., temperature (377‑427 K), particle size (0.5‑1.5 mm), space-time (15.89‑42.5 kg h/k mol), benzene to isopropyl alcohol mole ratio (2‑8) and weight of catalyst (0.03‑0.05 kg) on benzene conversion and cumene selectivity in a fixed bed reactor. The kinetics was found to be reaction controlled with negligible mass transfer effects for the given particle size range. Based on the product distribution, a mechanism of the cumene synthesis over the catalyst and the corresponding rate expression was proposed. The activation energies for various reactions were calculated from the estimated kinetic constants. The activation energy values compared well with those reported by other investigators for the same reactions over similar catalysts.

Keywords: Alkylation, benzene, cumene, isopropyl alcohol (IPA), ce-exchange, 13X zeolite, kinetics