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Abstract:
Materials that enable tandem transformations offer substantial advantages in catalysis
by reducing the number of separation steps. Typical examples are rattle-type materials
that provide spatial isolation of matter and confinement of active centers which may
favor the implementation of sequential catalytic cycles. However, the controlled
synthesis of these solid catalysts suffers from several limitations. Therefore, the first
part of the thesis addresses this aspect by studying the influence of various parameters
in the synthesis of these materials including advanced oxidative methods such as gas-
phase ozone treatment. In this first part, the synthesis is targeted at the development
of catalysts for liquid phase transformation of glucose to furan derivatives such as HMF
and FDCA.
Liquid phase mass-transfer properties of rattle-type materials (e.g. diffusion
constants) provide vital insight into their reactivity, especially for sequential reactions.
However, obtaining diffusion constants within these materials under relevant reaction
conditions is not easy. To this end, the second part of the thesis deals with the
development of setups for these measurements in the liquid and gas phases.
Breakthrough curves or uptake curves obtained from the experiments are fitted by an
iterative simulation of the diffusion-advection equations via MATLAB. The best fit
provides the required diffusion constants which can be correlated to the activity of
catalysts. Therefore, the implementation of the solution and the development of the
setup are major aspects of the second section of the thesis.
The third part of the thesis deals with establishing a synergy between the three
sequential reactions for the cascaded transformation of glucose to FDCA. This is
attempted by modifying the hierarchical catalysts (rattle-type catalysts) with the
required properties. The entire reaction scheme involves isomerization, dehydration
and oxidation steps. A moderate-throughput approach is used to screen various hybrid
materials and the reaction parameters to obtain the desired yield and selectivity.
Overall, the impact of the thesis in the field of catalysis is to formulate a strategy
towards the synthesis of rattle-type catalysts and the development of catalytic systems
for tandem transformations with special focus on mass transfer properties.
