Fe@Hierarchical BEA Zeolite Catalyst for MW-Assisted Alcohol Oxidation Reaction: A Greener Approach

Abstract

The aim of this study was to investigate the catalytic activity of hybrid materials of iron supported on hierarchical zeolites in the oxidation reaction of 1-phenylethanol to acetophenone. A greener approach was considered for the preparation of the catalyst and performance of the oxidation reaction. Hierarchical BEA zeolite samples were obtained from an alkaline and a subsequent acid treatment. The materials were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and nitrogen adsorption at −196 °C. An iron salt was incorporated onto the hierarchical zeolites by mechanochemical grinding and the catalytic performance of the prepared materials was evaluated towards the microwave assisted oxidation reaction of 1-phenylethanol. The catalyst obtained by Fe immobilization on sample modified by 0.2 M NaOH followed by acid treatment (Fe@BEA0.2AT) is the most promising material with 35% yield and 56% selectivity to acetophenone, allowing five reuse cycles without significant loss of activity and selectivity.

Exploring the Effect of Hierarchical Porosity in BEA Zeolite in Friedel-Crafts Acylation of Furan and Benzofuran

“…BEA zeolite (Si/Al ratio = 12.5) was subjected to alkaline treatment with 0.2 or 0.4 M NaOH solutions at 60 • C for 30 min and, in some cases, it was followed by an acid washing with 0.1 M HCl at 70 • C for 3 h. The samples were labeled as BEAx, where x is the NaOH concentration, followed by AT in the case of acid treated materials. The X-ray powder diffraction patterns of parent and modified samples, and the N 2 adsorption isotherms at −196 • C were presented in a previous work [21]. The degree of crystallinity (%) of the modified samples, C XRD , estimated based on the area of the peak at 2θ around 22…”

“…Hierarchical BEA samples were prepared through post-synthesis treatments using the methodology applied in our previous works [15,19,21]. In brief, the zeolite in its protonic form, herein designated as BEA, was submitted to an alkaline treatment with 0.2 or 0.4 M NaOH (p.a.…”

“…Parent and hierarchical materials were characterized through several techniques; some of them were already thoroughly described in previous works [19,21]. The structural characterization was carried out using X-ray powder diffraction (Philips, Analytical PW 350/60 X'Pert PRO with X'Celerated detector, Almelo, The Netherlands).…”

Zeolites and Related Materials as Catalyst Supports for Hydrocarbon Oxidation Reactions

“…To apply this synthesis methodology, it is necessary that the solid surface has functional groups that can react with the complex (either with the metal or with the ligands) during the immobilization, which is promoted by refluxing the mixture support-complex, typically overnight. The final steps are the usual washing and drying processes [74,100].…”

New avenues for mechanochemistry in zeolite science

“…In another study, Andrade et al used ball milling for loading of iron unto conventionally prepared hierarchical zeolite beta. 123 Hydrated iron chloride was mixed with the zeolite in a planetary ball mill and the resulting material exhibited enhanced properties in the oxidation of 1-phenylethanol, conducted in a microwave. It is, however, unclear what the nature of the resulting iron species is and how well they are distributed throughout the zeolite support.…”