Embryonic zeolites: a novel catalyst for cascade reactions

Abstract

Cascade reactions are essential in the synthetic route of several molecules. Due to the number of sequential steps, many separation and purification operations are required in these processes. To overcome this problem, the single-step synthesis of multifunctional catalysts is a current and quite relevant challenge, since it reduces the number of operations, reducing residue levels and increasing the economic potential of these processes. Several cascade reactions involve bulky molecules, which are difficult to process in heterogeneous catalysts, whose pore size and specific area limit the accessibility to catalytic sites. Therefore, this project intends to produce multifunctional acid-base catalysts, for reactions that involve the cascade processing of bulky molecules. For this, the reduction of the diffusional limitation will be the focus of the work, which will be approached with the use of a new type of catalyst: embryonic zeolites. Embryonic zeolites, whose organization occurs only in the short range, present catalytic sites very exposed, and therefore very accessible, which gives them catalytic activity superior to the crystallized zeolites. This work intends to develop and apply new catalytic materials containing basic and acidic sites present in embryos of functionalized acid zeolites with organic basic sites through different anchoring techniques. The performance of these catalysts will be evaluated by the deacetalization reaction followed by Knoevenagel condensation, a model reaction for the test of acid-base catalysts, with potential for the synthesis of fine chemicals. (AU)