Continuous, Fast, and Safe Aerobic Oxidation of 2-Ethylhexanal: Pushing the Limits of the Simple Tube Reactor for a Gas/Liquid Reaction

Abstract

A continuous-flow microreactor is applied for the selective aerobic neat oxidation of 2-ethylhexanal. Under 7.5 bar of O2 and 10 ppm of Mn(II) as catalyst, a production of up to 130 g/h of 2-ethylhexanoic acid can be obtained with a PFA tubing of 7 m (Ø 1.65 mm, reactor volume ca. 15 mL). The synergistic use of alkali metal salts and Mn(II) as catalyst improve the selectivity up to 94% under those conditions. We show that the productivity of this simple tube microreactor is limited by the thermal management.