1,721,765 research outputs found
Thiol-functionalized ethylene periodic mesoporous organosilica as an efficient scavenger for palladium : confirming the homogeneous character of the Suzuki reaction
Full text linkThis work describes the synthesis of thiol-functionalized periodic mesoporous organosilicas (PMOs) prepared using the precursor 1-thiol-1,2-bis(triethoxysilyl)ethane, alone or mixed with 1,2-bis(triethoxysilyl)ethane. The thiol groups incorporated into the structure were found to be efficient for palladium binding. This has allowed these materials to be used as catalysts in the Suzuki cross-coupling reaction of bromobenzene and phenylboronic acid. Their performance has been compared to palladium-supported periodic mesoporous (organo)silicas and important differences have been observed between them. The use of different heterogeneity tests, such as hot filtration test and poisoning experiments, has provided a deep insight into the reaction mechanism and has confirmed that the reaction occurs in the homogeneous phase following a "release and catch" mechanism. Furthermore, the thiol-functionalized periodic mesoporous organosilica, synthesized using only 1-thiol-1,2-bis(triethoxysilyl)ethane as a precursor, has proven to be an efficient palladium scavenger
Design of covalent triazine frameworks for selective carbon capture and storage
No full textA significant and ongoing challenge of the world is the continuous emission of carbon dioxide, which is mainly produced from the burning of fossil fuels and is widely accepted to be the primary contributor to global warming. A cleaner and sustainable future for the world with the transition of energy dependence from fossil fuels to more renewable and green energy sources is regarded as an ideal concept for a long time, however, there are too many obstacles and it really needs long time before the realization of this goal in practice. One can foresee that fossil fuels will still be the dominant source of energy for humans in the near future and it is absolutely and urgently required to explore more efficient and economical techniques for the reduction of the atmospheric CO2 concentration. As a newly emerging class of advanced porous materials, metal organic frameworks (MOFs) and covalent organic frameworks (COFs) have exhibited promising potentials for the application of gas adsorption and separation due to their unique features and they are now being extensively studied and explored by both academic and industrial scientists.
In this thesis, we are especially interested in a subclass of covalent organic frameworks, namely covalent triazine frameworks (CTFs), which exhibit exceedingly high thermal and chemical stability, high permanent porosity, easy tunability and functionalities as well as rich CO2-philic sites and they are supposed to be the excellent platforms for the application of carbon capture and separation. Thus, in this thesis, we designed and prepared different types of monomers with different types of functional groups as the building blocks for the construction of porous CTF materials and consequently explored and evaluated their gas adsorption and separation potentials
Versatile hybrid nanomaterials : periodic mesoporous organosilicas as adsorbent and catalyst
Full text linkDevelopment of nanocasting synthesis routes for thermoelectric efficiency enhancement in bulk nanowire composites
No full textMetal and covalent organic frameworks for advanced applications : heterogeneous catalysis and sensing
Full text linkFunctionalized porous (organo)silicas for applications in enamine catalysis and photocatalysis
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