Abstract

Continuous Flow Aerobic Oxidation Reactions using Heterogenous Catalyst

Alain Favre-Reguillon, Associate Professor, University of Lyon

In recent years, catalytic aerobic oxidation reactions in the liquid phase have become an important topic, driven by the need for reaction technologies that can be employed for biomass conversion, and for more sustainable processes for the fine chemicals and pharmaceutical industries. In terms of process safety and control, it is widely acknowledged that aerobic oxidation reactions are best implemented in continuous flow.

Arguably, one of the most challenging reactions is the selective oxidation of alcohols to aldehydes and ketones, a process that is ubiquitous in organic chemistry. However, it is still one of the least efficient, engendering the development of a large number of methodologies. Ruthenium-based heterogeneous catalysts exhibit a broad substrate scope, including tolerance to heterocycles and other functional groups commonly encountered in pharmaceuticals and fine chemicals and was adapted in flow.

Furthermore, in a flow regime, the longevity of a catalyst is a major determinant of its economic viability. Therefore, it is important to understand how catalyst activity (TOF) is affected by reaction parameters like temperature, O₂ pressure, gas/liquid flow rates, solvent effect, alcohol concentration as well as deactivation mechanisms. Our recent results on continuous flow aerobic oxidation reactions using Ru/Al₂O₃ will be presented and also compared to Cu/TEMPO homogeneous catalytic system.