Deactivation of Molecular Sieves in the Synthesis of Organic Chemicals

The term deactivation indicates any kind of progressive loss of activity of a catalyst with increasing reaction time. Any sort of catalyst, either homogeneous or heterogeneous, is subject to deactivation and the deactivating processes take place during the intermediate time between the status of fresh catalyst (as-synthesised or as-prepared) and the one of spent catalyst (when the catalytic activity is zero). Nevertheless, deactivation phenomena are particularly relevant for heterogeneous catalysts, since the factors leading to the deactivation of solid systems are more abundant than those occurring for homogeneous ones and, for these reasons, catalyst stability (or catalyst robustness) is one of the most sought-after properties in solid materials together with good activity (in terms of reaction rate and substrate conversion) and high selectivity to desired products