Molecular sieves are type A zeolites with specific sized pores and are commonly used in organic synthesis to capture small molecules such as water. In addition to their trapping effect, they also have acidic and basic active sites and are used as solid acid-base catalysts. Usually, heat-drying treatments are performed prior to use, but the heat treatment methods, such as microwave ovens or heat guns, are not standardized, which could cause problems in reproducibility of reactions. Particularly, for reactions requiring acid/base sites of molecular sieves, these treatment methods are considered more sensitive because the structure of the active sites changes upon heating. In this article, we propose new methods of activation when using molecular sieves and their application to continuous-flow reactions.
