Helically coiled segmented flow tubular reactor for the hydroformylation of long-chain olefins in a thermomorphic multiphase system

To intensify new or existing chemical processes, novel reactor designs have to be developed. For a homogeneously catalyzed multiphase model reaction, the hydroformylation of 1-dodecene, Kaiser et al. [13] theoretically derived a promising tandem reactor system applying a model-based rector synthesis and dimensioning approach. The reactor tandem, consisting of a helically coiled tubular reactor (HCTR) followed by a continuously stirred tank reactor (CSTR), was constructed and firstly operated within this work. For the validation of the reactor design methodology, a comprehensive hydrodynamic study focusing on the HCTR was performed. Different complementary techniques were used to investigate the geometry influences on mixing and the gas-liquid mass transfer, and liquid phase mixing in smaller model geometries. Since the same Reynolds-number and flow regime in the model geometries and the HCTR were ensured, the transfer of the results between these geometries was possible. The outcome confirms, that the geometrical parameter only minor influence the excellent mixing properties of coiled tubes and the helix geometry has enhanced gas-liquid mass transfer rates. In a next step, the HCTR + CSTR-tandem was operated with closed catalyst recycle and optimized reaction parameters. Thereby, full conversion of 1-dodecene and a selectivity of up to 0.70 to the linear aldehyde, tridecanal, were achieved. These values match the predictions of the numerical calculations and are higher than published results for this process. The outcomes of this study confirm the assumptions made by Kaiser et al. [13] during the reactor dimensioning and validate the reactor network design approach.