Authors: Aleksei Bolshakov
Source: Data Archiving and Networked Services (DANS) (article, 2019-12-06)
Field: Chemistry — Inorganic Chemistry

Versatile mesoporogens for the synthesis of hierarchically porous zeolites and their catalytic applications Chapter 1 Introduction and scope 1 Chapter 2 Mordenite nanorods prepared by an inexpensive pyrrolidine-based mesoporogen for alkane hydroisomerization 21 Chapter 3 Mild dealumination of template-stabilized zeolites by NH4F 49 Chapter 4 A versatile mono-quaternary ammonium salt as mesoporogen for the synthesis of hierarchical zeolites 77 Chapter 5 Hierarchically porous (alumino)silicates prepared by an imidazolebased surfactant and their application in acid-catalyzed reactions Chapter 6 Hierarchically porous FER zeolite obtained via FAU transformation for fatty acid isomerization Summary and outlook Acknowledgements List of publicationsCurriculum Vitae a fast deactivation of the catalyst.Hence, hierarchical zeolite are very promising for these processes similarly to the methanol-to-hydrocarbons reactions.Overall, introduction of a second level of porosity in microporous zeolites results in improved catalytic performance in many relevant reactions, increasing yield of desired products, better utilization of the microporous space and prolonged lifetime of the catalyst.A large number of examples evidences a broad applicability of hierarchical zeolites in modern fossil-based and future renewable chemical industries. Scope of thesisIn this study, simple organic surfactants, which can be easily obtained from commercially available precursors, were investigated as mesoporogens in the synthesis of hierarchically porous zeolites.Several zeolite structures were targeted with a view on developing improved catalysts for relevant reactions in the chemical industry.Mono-quaternary ammonium salts containing pyrrolidinium-or imidazolium-based head groups were used as a cheap dualfunctional surfactant or as mesoporogen in SDA-assisted zeolite synthesis.MOR, FER, CHA and MFI topologies, which have a wide practical application, were selected for the incorporation of secondary porosity.The focus was on understanding the impact of the organic template on the morphological, textural and acidic properties of the final materials.Catalytic properties of the hierarchically porous zeolites were assessed in several important reactions including the hydroisomerization of n-paraffins, methanol-to-hydrocarbons reaction, n-butanol dehydration/isomerization, Friedel-Crafts alkylation and fatty acid isomerization.Chapter 2 describes the direct synthesis of mordenite nanorods using inexpensive pyrrolidinium-based amphiphilic surfactant N-cetyl-N-methylpyrrolidinium bromide (C16NMP) which simultaneously acts as an SDA and mesoporogen.The synthesis conditions were optimized with respect to the composition of the synthesis gel.The effect of the mesoporogen on the acidic and textural properties of the MOR materials was studied in detail.Prepared bifunctional hierarchical Pd-HMOR catalysts demonstrated an improved catalytic performance in n-hexadecane hydroisomerization.Chapter 3 presents a new approach of mild zeolite dealumination by hydrothermal treatment of template-stabilized zeolites with concentrated NH4F solution.The influence of different types of organic templates, the treatment time, the concentration of NH4F and treatment temperature on textural and acidic properties of ZSM-5(MFI) zeolite was studied.The method Porosity ; Materials science ; Nanotechnology ; Catalysis ; Chemical engineering ; Porous medium ; Chemistry ; Engineering ; Organic chemistry ; Composite material Zeolite Catalysis and Synthesis ; Mesoporous Materials and Catalysis ; Nanomaterials for catalytic reactions