Rotating Foam Reactors for Fine Chemical Synthesis

The production of fine chemicals and pharmaceuticals is commonly performed in batch reactors, using slurry catalysts, due to their high flexibility. However, the catalyst particles need to be filtered from the slurry when the reaction is finished, which is a costly and time consuming operation and makes re-using the catalyst difficult. In this presentation we will be showing the development of new three-phase reactor configurations based on the application of solid foam packings. These materials have a good mechanical stability, a high porosity, and a high specific surface area, which offers great potential for their use as catalyst packings. The good mechanical strength, allows us to use the material as both catalyst support and stirrer at the same time. The foam surface area can be further increased by deposition of a catalyst wash coat or using sol-gel methods.

We will be showing that the solid foam stirrer reactor has an efficient mixing behavior and high mass transfer rates. Additionally, the reaction mixture can be drained off easily, without the need to filter the catalyst particles. Using different cell-density foams (different geometrical surface areas) and different washcoat thicknesses it is possible to optimize the performance of the reactor in cases where the catalyst activity and mass transfer are effecting the selectivity of a reaction, for example in the selective hydrogenation of an alkyne to an alkene. We will be showing the performance of this novel reactor type for different gas-liquid reactions catalyzed by a heterogeneous catalyst coated on the stirrer. We will be comparing its performance to conventional slurry catalysts in a reactor equipped with a conventional Rushton stirrer.