The influence of reactor fluid-dynamics during zeolite synthesis: The synthesis and the cracking activity of hierarchical ERS-10 A zeolite

Abstract Zeolite ERS-10 crystallizes with different structural arrangements and morphologies. In particular, ERS-10 A shows interesting specific surface area and peculiar core–shell morphology, giving a hierarchical porous structure generated by NES zeolite nanocrystals epitaxially grown on a disordered substrate constituted by an intergrowth of  NON - EUO - NES - EEI zeolite. But the synthesis of this catalyst is not straightforward: the fluidodynamics of the reagent mixture during ERS-10 A formation plays a pivotal role on the structure of the final product. Computational Fluid Dynamic simulations allowed to define the stirring system, the fluid motion, the liquid and reagent distribution favorable to the obtainment of the desired phase. High stirring rate during the silica source (tetraethyl-ortosilicate) addition and hydrolysis is required to permit homogeneous distribution of reagents and the crystallization of pure ERS-10 A. The catalytic properties of ERS-10 A are compared with those of FAU and MFI zeolites in the cracking of methylcyclohexane. The behavior of ERS-10 A is in the middle between medium and large pore-zeolites, in agreement with highly accessible active sites, due to its peculiar hierarchical micro–mesoporous system.