Preparation of Pd-Loaded Hierarchical FAU Membranes and Testing in Acetophenone Hydrogenation.

Raffaele Molinari,Enrico Drioli,Teresa Poerio,Teresa Mastropietro,Cristina Lavorato,Pietro Argurio

doi:10.3390/molecules21030394

Abstract

Pd-loaded hierarchical FAU (Pd-FAU) membranes, containing an intrinsic secondary non-zeolitic (meso)porosity, were prepared and tested in the catalytic transfer hydrogenation of acetophenone (AP) to produce phenylethanol (PE), an industrially relevant product. The best operating conditions were preliminarily identified by testing different solvents and organic hydrogen donors in a batch hydrogenation process where micron-sized FAU seeds were employed as catalyst support. Water as solvent and formic acid as hydrogen source resulted to be the best choice in terms of conversion for the catalytic hydrogenation of AP, providing the basis for the design of a green and sustainable process. The best experimental conditions were selected and applied to the Pd-loaded FAU membrane finding enhanced catalytic performance such as a five-fold higher productivity than with the unsupported Pd-FAU crystals (11.0 vs. 2.2 mgproduct gcat−1·h−1). The catalytic performance of the membrane on the alumina support was also tested in a tangential flow system obtaining a productivity higher than that of the batch system (22.0 vs. 11.0 mgproduct gcat−1·h−1).

Highlights

Reduction processes are among the prevalent transformations in organic chemistry and are widely applied in industrially relevant practices [1]
In the pharmaceutical and biotechnological industries, the synthesis processes for the preparation of a wide range of compounds often imply the conversion of functional groups, the reduction of a carbonyl moiety to the corresponding alcohol being one of the most commonly required intermediary transformations [2,3]
In the catalytic tests in aqueous media, all withdrawn samples were diluted with 50% of ethanol before to be filtered in order to avoid adsorption of reactant and products on the polypropylene membrane

Summary

Introduction

Reduction processes are among the prevalent transformations in organic chemistry and are widely applied in industrially relevant practices [1]. Many well-established and routinely applied technologies for carbonyl reduction need to be revised to meet the more stringent standards of safety and efficiency currently imposed by regulatory agencies in many countries worldwide. Both industry and academia have placed a special emphasis on the design of more sustainable processes and technologies which can be reliably implemented in large scale production.

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