Investigation of mass transfer limitations on heterogeneously catalyzed ring opening polymerization of propylene oxide Tabea Angela Thiel 1 , Michael Schwarze 2 , Mahsa Sadeghi 1 , Esteban Mejía 1 1 Leibniz-Institut für Katalyse e. V. (LIKAT), Rostock, Germany, 2 Technische Universität Berlin, Berlin, Germany The bulk ring opening polymerization of propylene oxide (PO) using heterogeneous (solid) catalysts is widely used to produce polypropylene glycol. The diffusion phenomena of growing polymers has been thoroughly investigated, both experimentally and by simulations. 1, 2 However, the influence of the monomer diffusion at the solid-liquid and gas-liquid interface has been so far either neglected or assumed as constant. The homopolymerization can be carried out in a temperature range of 60-120°C, in which the neat PO would be in the gas phase. 3 Thus this a multi-phase reaction where the liquid phase becomes viscous, so the phase transport limitations of the PO should be considered. The temporal change of the PO concentration in the liquid phasecan be derived from the mass balance. The target of the presented investigation is to characterize the PO distribution in the gas and liquid phase with varying total amounts of monomer at different temperatures (60-120°C) and their influence on the resulting kinetic parameters during the ring-opening polymerization with a heterogeneous zinc-based catalyst. 4, 5 Here, the influence of phase transfer limitations on the reaction process was investigated via the experimental recording of time-dependent PO concentration in the liquid phase and compared with the mathematical modeling of the PO concentration. Our results show that the amount- and temperature-dependent distribution of PO have a significant influence in the reaction. The knowledge about the PO distributions and resulting phase transfer limitations might require the reassessment of previously published kinetic investigations. 6 References 1. R. Bachmann, M. Klinger and A. Jupke, Macromolecular Theory and Simulations , 2021, 30 . 2. M. Klinger, R. Bachmann and A. Jupke, Macromolecular Theory and Simulations , 2021, 30 . 3. S.-F. Stahl and G. Luinstra, Catalysts , 2020, 10 . 4. WO2019243067 A1, 2019. WO2012136657 A1, 2012. L.-C. Wu, A.-F. Yu, M. Zhang, B.-H. Liu and L.-B. Chen, Journal of Applied Polymer Science , 2004, 92 , 1302-1309.
P53
© The Author(s), 2023
Made with FlippingBook Learn more on our blog