Summary: A nanoscopic heterogeneous catalyst system based on zinc glutarate is used to prepare poly(propylene carbonate) (PPC) from CO 2 and propylene oxide (PO). The catalyst was exposed to a defined humid atmosphere. The water uptake resulted in a deactivation to a minimum of 25% of the original activity, depending on time of exposure and water concentration. In addition, the progress of the copolymerization at constant pressure was monitored by measuring the CO 2 uptake. It is shown that the rate is linear with time after an initial phase and that this rate is in linear correlation with the amount of catalyst. The copolymerization was also performed in several modes of discontinuous addition of PO. The productivity of the catalyst was in the range of 1.6-2.0 kg PPC/g Zn, the highest productivity reported for the zinc carboxylate catalyst system so far. High molecular weights of around 220 kg/mol (M w ) and low polydispersities of 2.2-2.5 were achieved in all experiments.