Oxidations of pyridine-like molecules to form n-oxides are reactions that are useful in the synthesis of APIs (advanced pharmaceutical intermediates). This oxidation can be performed continuously with process intensification using green reagents such as aqueous hydrogen peroxide and acetic anhydride in a solventless system.

The plug flow reactor consists of a jacketed static mixer with a novel inlet configuration, and heat-exchanger residence-time modules. This reactor configuration allows for the reaction to be run safely at elevated temperatures with high reaction conversion and minimal side reactions. The modular design allows for the existing equipment to be transferred from lab scale to kilo facility to pilot plant with the addition of more residence modules and scale appropriate pumps.

This approach can be extended further to other highly exothermic reactions, thus utilizing continuous reactors to extend the benefits of the green chemistry paradigm to a wider range of processes.