X-ray crystallographic analysis of ADORable zeolites and metal-organic frameworks

This thesis largely focuses on the mechanistic analysis of the Assembly-Disassembly- Organisation-Reassembly (ADOR) process through a range of crystallographic techniques including powder X-ray diffraction and Pair Distribution Function (PDF) analysis and subsequent analysis using solid-state kinetics. Chapter 4 describes the development of a new standard protocol to using the ADOR process. The protocol describes the development of a procedure used for identifying the optimum conditions (time of reaction, temperature, acidity, etc.) for the ADOR process. In developing the protocol, Ge-containing UTL zeolites were subjected to hydrolysis conditions using both water and hydrochloric acid as media, which provides an understanding of the effects of temperature and pH on the Disassembly (D) and Organisation (O) steps of the process that define the potential products. Samples were analysed by powder X-ray diffraction to yield a time course for the reaction at each set of conditions. Chapter 5 continues work on the ADOR process and presents the first kinetic study on the two most prominent steps in the process; Disassembly and Organisation. By using solid- state kinetic models, Avrami-Erofeev and its linear equivalent Sharp-Hancock, the dependence on temperature and presence of liquid water was investigated and the activation energy of the rearrangement process quantified. Work on the rearrangement step aimed to understand where the silica species intercalates from and which material formed as the kinetic and thermodynamic product from the reaction. Chapter 6 describes a study into the Disassembly and Organisation steps of the ADOR process through in situ Pair Distribution Function (PDF) analysis. This hopes to shed light on the selectivity of the ADOR process in different media and the mechanism by which the double-four-ring (d4r) breakdown. On a different note, Chapter 7 describes the refinement of synthesis conditions used to prepare poly-crystalline CPO-27-M (MOF-74) with lower concentrations of base and at low temperature. Refinement of the synthesis of single crystal CPO-27-Mg, -Zn and UTSA-74 was undertaken and the necessary components to forming large single crystals understood

Synthesis and crystallographic characterisation of Mg(H2dhtp)(H2O)5·H2O

This work was funded by the British Heart Foundation (NH/11/8/29253) and the EPSRC (EP/K005499/1) (EP/K503162/1). CCDC 1432662 contains the supplementary crystallographic data for this paper. These data can be obtained free of charge from The Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_request/cif.A mononuclear complex of composition Mg(H2dhtp)(H2O)5·H2O has been prepared and characterised crystallographically.PostprintPostprintPeer reviewe

Kinetics and mechanism of the hydrolysis and rearrangement processes within the assembly-disassembly-organization-reassembly synthesis of zeolites

The authors would like to thank the EPSRC (grants: EP/K025112/1; EP/K005499/1; EP/K503162/1; EP/N509759/1) for funding opportunities. R.E.M., and M.M. would like to acknowledge OP VVV "Excellent Research Teams", project No. CZ.02.1.01/0.0/0.0/15_003/0000417 - CUCAM. We would like to thank the ERC (Advanced Grant 787073 “ADOR”).The hydrolysis (disassembly, D) and rearrangement (organization, O) steps of the assembly-disassembly-organization-reassembly (ADOR) process for the synthesis of zeolites have been studied. Germanium–rich UTL was subjected to hydrolysis conditions in water to understand the effects of temperature (100, 92, 85, 81, 77, and 70 °C). Samples were taken periodically over an 8–37 h period and each sample was analyzed by powder X-ray diffraction. The results show that the hydrolysis step is solely dependent on the presence of liquid water, whereas the rearrangement is dependent on the temperature of the system. The kinetics have been investigated using the Avrami-Erofeev model. With increasing temperature, an increase in rate of reaction for the rearrangement step was observed and the Arrhenius equation was used to ascertain an apparent activation energy for the rearrangement from the kinetic product of the disassembly (IPC-1P) to the thermodynamic product of the rearrangement (IPC-2P). From this information a mechanism for this transformation can be postulated.Publisher PDFPeer reviewe

Kinetics and mechanism of the hydrolysis and rearrangement processes within the assembly-disassembly-organization-reassembly synthesis of zeolites

The hydrolysis (disassembly, D) and rearrangement (organization, O) steps of the assembly-disassembly-organization-reassembly (ADOR) process for the synthesis of zeolites have been studied. Germanium–rich UTL was subjected to hydrolysis conditions in water to understand the effects of temperature (100, 92, 85, 81, 77, and 70 °C). Samples were taken periodically over an 8–37 h period and each sample was analyzed by powder X-ray diffraction. The results show that the hydrolysis step is solely dependent on the presence of liquid water, whereas the rearrangement is dependent on the temperature of the system. The kinetics have been investigated using the Avrami-Erofeev model. With increasing temperature, an increase in rate of reaction for the rearrangement step was observed and the Arrhenius equation was used to ascertain an apparent activation energy for the rearrangement from the kinetic product of the disassembly (IPC-1P) to the thermodynamic product of the rearrangement (IPC-2P). From this information a mechanism for this transformation can be postulated

In situ flow pair distribution function analysis to probe the assembly-disassembly-organisation-reassembly (ADOR) mechanism of zeolite IPC-2 synthesis (dataset)

Underpinning data for open access publicatio