Protective desilication of β zeolite: A mechanism study and its application in ethanol-acetaldehyde to 1,3-butadiene

The conversion of bioethanol to 1,3-butadiene (ETB) is expected to be one of the most promising routes to alternate the petroleum route. However, the preparation of hierarchical β zeolite to serve as the catalyst support is still challenging. In this work, hierarchical β zeolite was prepared through protective desilication by quaternary ammonium hydroxide (TAAOH), and Zr-β zeolite was prepared using the hierarchical β zeolite by dealumination-metallization strategy for ETB reaction. The mechanism of protective desilication was clarified by some control experiments. The protection of TAA+ coexists with OH- attacking and they act in different treating stage, and there lies the best treatment concentration regarding to the mesoporous formation in β zeolite. By adjusting the length of TAAOH alkyl chain, the mesoporosity of β zeolite was tuned successfully. The catalytic activity of Zr-β zeolite was enhanced by the generation of mesoporosity and better capability of coke was achieved which mitigated the deactivation.