Syllabus
Zeolites and microporous inorganic materials:
1. Microporous materials Meaning and use of zeolites and microporous materials. Definitions of basic terms, aluminosilicates (natural and synthetic zeolites), microporous materials based on aluminophosphates, pillared clays and mesoporous materials (MCM-41,
48). Chemical composition. Basic principles for the construction of primary building units (secondary building units), their interconnection in the three-dimensional structure. Alternating individual elements in the framework (Lowenstein rule). Natural zeolites – classification based on structure similarity, basic properties, utilization. Adsorption on zeolites. Cations and their localization in various zeolite structures. Relationships between natural and synthetic analogues, basic structural types (A, X, Y, FAU, MOR, ERI, MFI, MTW, MEL, TON, etc.).
2. Synthetic zeolites (microporous materials based on aluminosilicates) Synthesis of zeolites (Si/Al ratio in the reaction mixture, presence of OH-, inorganic cations, anions, water, role of organic templates, time, temperature, seeding, crystal size). The role of templates in the synthesis of zeolites. Incorporation of other elements into the zeolite framework, stability, properties. Molecular modeling of templates for the preparation of new zeolite structures. Synthesis of large crystals, acceleration of synthesis, synthesis in acid environment (fluoride method). Removal of templates, calcination, ion exchange of ammonium or metal ions into cationic zeolite positions. Acidity of zeolites - the strength of acid sites, the number of active centers (dependence on atoms forming the lattice). Brønsted and Lewis centers. Evidence of successful incorporation of heteroelements into the zeolite framework (XRD, NMR, FTIR).
3. Synthetic aluminophosphates Synthesis of aluminophosphates (P/Al ratio in the reaction mixture, presence of OH-, inorganic cations, anions, water, role of organic templates, time, temperature, seeding, crystal size). The role of templates in the synthesis of aluminophosphates, the incorporation of Si into the crystalline lattice, the alternation of Al - P - Si. Incorporation of other elements into the aluminophosphate framework, stability, properties. Differences between aluminophosphates and aluminosilicates. Synthesis of AlPO materials in acid medium (fluoride method). Acidity of aluminophosphates – types and number of active centers (dependence on framework elements). Proof of successful incorporation of heteroelements into the zeolite framework (XRD, NMR, FTIR, UV-VIS).
4. Mesoporous materials and porous layered structures Zeotypes (aluminophosphates, gallo-phosphates), pillared layered solids, mesoporous molecular sieves (MCM, hexagonal vs. cubic). Synthesis, properties, use in catalysis or as supports for catalytically active systems.
5. Characterization of the structure of mesoporous materials Use of instrumental analytical techniques to determine crystallinity and structure (XRD, FTIR, MAS NMR, SEM, sorption of gases and organic molecules). Basic principles of characterization techniques, instrumentation, experimental possibilities, types of information obtained. The necessity of combining experimental techniques, limitations of individual techniques and their complementation. Characterization of individual types of materials, localization of cations in the framework or in the channels of a given zeolite.
6. Experimental methods in heterogeneous catalysis Methods of dosing of reactants in heterogeneous catalysis (chokes, linear dispensers, product condensation, dosing loops), reaction product analysis (off-line and on-line analysis, gas chromatography, infrared spectroscopy, NMR, MS). Types of reactors, "in-situ" techniques, interconnection of catalytic equipment with analytical technique, combination of analytical methods (FTIR-GC, FTIR-MS, GC-MS).
7. Zeolites in organic synthesis An overview of organic chemistry on zeolites, the role of the structure in the course of the reaction and formation of the desired products (acid-base catalysis, redox catalysis). Relationships between the structure of the zeolite, its acid-base or redox properties and the course of the reaction.
8. Modification of zeolites Modification of zeolites to increase the selectivity of the reaction, reduce deactivation. Location of active centers on external vs. inner surface, blocking non-selective centers. Formation of organometallic catalytically active centers in the channel structure of zeolites.
9. Determination of mechanisms of organic reactions on zeolites Appropriate choice of experiment conditions, balancing experimental procedure, use of experimental techniques in determining the mechanism of organic reactions. Labeled compounds, use of isotopes to prove the mechanism. Choice of the appropriate experimental method (FTIR, 13C MAS NMR, GC-MS). Formation of intermediates.
10. Industrial use of zeolites Catalytic processes based on the use of zeolites.
11. Special applications Synthesis of zeolites on metal surfaces, porous materials, cellulose, teflon, zeolitic membranes
Annotation
Cílem toho předmětu pro doktorandy je seznámit se základními principy syntézy zeolitů molekulových sít, jejich strukturami a vlastnostmi. V návaznosti jsou diskutovány současné aplikace zeolitů a možné budoucí praktické využití.