Exploration of rectangular waveguides as a basis for microwave enhanced continuous flow chemistries

In the context of microwave enhanced chemistry, usually a narrow set of single and multimode cavities are considered as microwave field applicators. This study aims to widen this current scope by exploring the potential of rectangular waveguides as a basis for microwave applicator systems. It is demonstrated that such systems offer microwave field patterns that are relatively simple and predictable, which makes processing amenable for adaption to specific requirements and for optimization. The feasibility of long residence time continuous flow chemistries under microwave conditions is demonstrated in a novel reactor type that the rectangular waveguide uniquely supports.

► Rectangular waveguides are explored as a tool for microwave enhanced chemistry. ► We show that such systems offer simple and predictable microwave field patterns. ► This makes adaption to specific requirements and optimization possible. ► A novel microwave-activated continuous flow reactor type is demonstrated. ► It is axially scalable and enables good and predictable microwave coupling.