Advances in Continuous Flow Calorimetry

Calorimetric data from chemical reactions such as reaction enthalpy, adiabatic temperature rise, and activation energy are essential for reaction safety and scale-up from laboratory investigations to reactor design and operation. Typically, these data are gained from batch calorimeters with sophisticated setups and elaborate measurement procedures. Continuous flow calorimeters, compared with batch setups, have different mixing and heat transfer characteristics and enable harsh reaction conditions, particularly within microstructured reactors with their enhanced heat transfer capability. This review provides an overview of currently investigated and applied flow calorimeters in research and development in relation to existing concepts. Novel approaches for heat flux measurements as well as integrated sensors are presented. Safety aspects of flow chemistry are a main driver, but additionally, low material consumption is important in early process development. Limitations of the concepts are presented with a comprehensive literature overview of flow calorimetry to show that continuous flow calorimeters form a new tool in process development and safety engineering, particularly with microstructured devices and novel sensing techniques.