Post‐Synthetic Ensembling Design of Hierarchically Ordered FAU‐type Zeolite Frameworks for Vacuum Gas Oil Hydrocracking

• Published in: Angewandte Chemie International Edition Vol. 63; no. 6; pp. e202314217 - n/a
• Main Authors: Kumar Parsapur, Rajesh, Hengne, Amol M., Melinte, Georgian, Refa Koseoglu, Omer, Hodgkins, Robert Peter, Bendjeriou‐Sedjerari, Anissa, Lai, Zhiping, Huang, Kuo‐Wei
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 05.02.2024
• Edition: International ed. in English
• Subjects: Catalysis; Catalysts; Channels; Crystallization; Diffusion; Diffusion rate; FAU-Type Zeolites; Gas oil; Gyroidal Mesoporosity; Hierarchically Ordered Zeolites; Hydrocracking; Mesophase; Molecular diffusion; Naphtha; Post-Synthetic Reorganization; Surfactants; Vacuum; VGO Hydrocracking; Zeolites; Hierarchically Ordered Zeolites; Gyroidal Mesoporosity; Post-Synthetic Reorganization; FAU-Type Zeolites; VGO Hydrocracking
• ISSN: 1433-7851; 1521-3773; 1521-3773
• DOI: 10.1002/anie.202314217

Zeolites hold importance as catalysts and membranes across numerous industrial processes that produce most of the world's fuels and chemicals. In zeolite catalysis, the rate of molecular diffusion inside the micropore channels defines the catalyst's longevity and selectivity, thereby influencing the catalytic efficiency. Decreasing the diffusion pathlengths of zeolites to the nanoscopic level by fabricating well‐organized hierarchically porous architecture can efficiently overcome their intrinsic mass‐transfer limitations without losing hydrothermal stability. We report a rational post‐synthetic design for synthesizing hierarchically ordered FAU‐type zeolites exhibiting 2D‐hexagonal (P6mm) and 3D‐cubic (Ia 3‾ ${\bar{3}}$ d) mesopore channels. The synthesis involves methodical incision of the parent zeolite into unit‐cell level zeolitic fragments by in situ generated base and bulky surfactants. The micellar ensembles formed by these surfactant‐zeolite interactions are subsequently reorganized into various ordered mesophases by tuning the micellar curvature with ion‐specific interactions (Hofmeister effect). Unlike conventional crystallization, which offers poor control over mesophase formation due to kinetic constraints, crystalline mesostructures can be developed under dilute, mild alkaline conditions by controlled reassembly. The prepared zeolites with nanometric diffusion pathlengths have demonstrated excellent yields of naphtha and middle‐distillates in vacuum gas oil hydrocracking with decreased coke deposition. Novel post‐synthetic ensembling design comprising methodical incision of conventional FAU‐type zeolites into unit‐cell level zeolitic fragments and their subsequent reorganization into hierarchically ordered zeolites exhibiting 2D‐hexagonal/3D‐cubic mesopore channels. This approach eludes the kinetic constraints of conventional crystallization to produce hierarchical zeolites having excellent catalytic properties in hydrocracking applications.