Sustainability of flow chemistry and microreaction technology

This critical review provides an overview of the sustainability outcomes associated with flow chemistry, as a new concept in process chemistry, and its related technology and engineering field, microreaction technology. This study is broad in scope and covers cost and life cycle assessment methodologies applied to flow chemistry. The present review differs from past studies by providing a mechanistic viewpoint, i.e., starting by listing key levers (e.g. mass transfer), and then unravelling their impact on costs and life cycle, using reported flow chemistry studies as examples to underline the sustainability capability. This way, this review transitions from informing on how flow chemistry and microreactors can improve fundamental principles in chemical engineering and chemistry to their translation to improved sustainability. Gaps and opportunities in the reporting of microreactor/flow chemistry are identified. To put the reported achievements into perspective, a life cycle assessment (LCA) study is conducted that reports on the effects of the key levers, as identified in this study, for a flow chemistry reaction at the pilot scale, conducted at an industrial site (technology readiness level 4). This way, this study provides a quantitative forecast of what principally can be achieved when maximising the key levers, in terms of the individual LCA impact categories and their total average outcome.