Making photochemistry scalable – an operationally simple falling film looping photoreactor

Abstract

Visible light-driven organic transformations have become very widespread due to their energy efficiency, process simplicity and high selectivity. Since photoreactions occur in a wide range of wavelengths and conditions, designing a specific reactor is very strenuous and challenging. Hence, different reactor types are required to meet the different demands of photoreactions but suited scale-up strategies do not yet exist for relevant reactor types. Crucial links for the scale-up process are still missing. Ideally, a scale-up process should be performed within the same type of reactor ensuring comparable reaction conditions. To resolve this issue, a new looping photoreactor was designed and manufactured that recirculates the reaction mixture and generates a falling film within the photoreactor. The reactor concept allows small-scale photoreactions to be carried out on a laboratory scale and demonstrates the scalability of the reactor concept without major changes to the reaction conditions up to productivities on the 1.7 kg per day scale.