Performance under microwave irradiation of catalysts doped with transition metal cations.

FEDERICO AZZOLINA JURY, LIONEL ESTEL, ISABELLE POLAERT, LILIANA PIERELLA

Naantali

Congreso; CAMURE 8 & ISMR 7; 2011

Zeolites are microporous crystalline aluminosilicates, widely used in industrial applications as catalysts, adsorbents and ion exchange supports[1]. Their unique layout confers specific pore opening size and void in framework. They can be quite easily doped by metal cations of transition, conferring to them some interesting adsorption and catalytic properties [2]. An interesting way of investigation is catalysis under microwave irradiation [3,4]. Because microwave heating occurs in a volumetric manner, a catalytic bed can be quickly and internally heated, directly where the reaction takes place, without requiring heat transfer from the surrounding media.  This study investigates the performances of two types of zeolites (FAU and MEL) doped with metal cations of transition (Ni, Co, Mn, Zn and Cr) under microwave irradiation. First, dielectric property measurements of the compacted catalytic beds were conducted at room temperature, from 0.5 to 20GHz, using a reflecting method (An example is given Figure 1). Second, the catalytic beds were heated under microwave and temperature profiles in the bed were determined Dielectric measurements were interpreted using a modified Debye Model [5] and heating.behaviors were confronted to dielectric properties. Finally, the catalytic activity of some doped zeolites was tested on the partial oxidation of styrene in a batch reactor under microwave irradiation. Cation nature, cation content and zeolite structure were found to be of main importance in the involved mechanisms.