Scale-Up Investigation of the Continuous Phase-Transfer-Catalyzed Hypochlorite Oxidation of Alcohols and Aldehydes

Abstract

The use of bleach to oxidize alcohols with the aid of a phase-transfer catalyst (PTC) offers several benefits over traditional oxidants: low material cost, mild reaction conditions, and no metallic waste. Mass transport limitations often dictate overall reaction rates of such PTC reactions, and continuous-flow reactors with superior mass and heat transport performance are consequently used to enhance their rates. Three PTC hypochlorite oxidation reactions are chosen to illustrate scaling of PTC reactions from microfluidic to mesoscale systems [Corning Low Flow Reactor (LFR) and Advanced Flow Reactor (AFR)]. The successful scaling from microliters per hour in microreactors to intermediate milliliters per minute without sacrificing mass transport performance leads to significant increases in production rate and constitutes an efficient flow reactor scaling approach. The production rate increases up to 700 times in the scaling process from a spiral microreactor to the LFR and then to the AFR.