Jetloop reactors show specific properties, such as intensive mixing and effective gas dispersion, which make them an interesting alternative for conventional reactor concepts in homogeneous multiphase catalysis. This contribution investigates the effect of specific power input and common additives in multiphase catalysis on bubble-size distributions in the draft tube and riser section of a miniplant-scale jetloop reactor and elucidates the coalescence during circulation. Finally interfacial areas are calculated and compared to standard reactors. (C) 2009 Elsevier Ltd. All rights reserved.