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Apeldoorn, Netherlands

Liu C.,Schuit Institute of Catalysis | Li G.,Schuit Institute of Catalysis | Hensen E.J.M.,Schuit Institute of Catalysis | Pidko E.A.,Schuit Institute of Catalysis | Pidko E.A.,TU Eindhoven
ACS Catalysis | Year: 2015

A comprehensive periodic DFT study complemented by ab initio thermodynamic analysis was carried out to determine the speciation of extraframework aluminum (EFAl) in faujasite zeolite. The structure and stability of a wide range of mono- bi-, tri-, and tetranuclear EFAl complexes stabilized at different locations in faujasite were investigated. The thermodynamic cycles connecting these complexes were constructed involving such elementary steps as hydration/dehydration, proton transfer, and condensation reactions. Using ab initio thermodynamics analysis it was predicted that, during high-temperature zeolite activation, the EFAl species self-organize into cationic clusters with more than one Al center. The resulting tri- and tetranuclear clusters are preferentially stabilized inside the small sodalite cages of faujasite that provide a favorable coordination and charge-compensation environment for the large multiply charged cationic clusters. The presence of such cationic EFAl clusters inside the inaccessible sodalite cages strongly enhances the protolytic propane cracking activity of vicinal supercage Brønsted acid sites. © 2015 American Chemical Society.


Grant
Agency: Narcis | Branch: Subprogram | Program: Completed | Phase: Technology | Award Amount: | Year: 2002

Wouldnt it be nice if one could oxidize olefins (to e.g. epoxides, diols, aldehydes) selectively using just air or hydrogen peroxide? Clean, atom- and energy-efficient. Unfortunately, oxidation with oxygen is one of the most complicated reactions you can find anywhere in catalysis. However, there is some interesting chemistry along the way! Selective oxidation of olefins and other unsaturated substrates is performed with the clean oxidants oxygen and hydrogen peroxide (in collaboration with the department of Organic Chemistry of the ETH Zürich and the department of Inorganic Chemistry and Catalysis of Eindhoven University of Technology). The reactions of the simple molecule O2 are invariably complex, and the combination with transition metals introduces additional complications. We have recently shown that - in contrast to many earlier proposals - paramagnetic intermediates are often required for the formation of the final (diamagnetic) products, and we try to use this new insight to effect new oxidation reactions.


Filot I.A.W.,Institute for Complex Molecular Systems | Filot I.A.W.,Schuit Institute of Catalysis | Palmans A.R.A.,Institute for Complex Molecular Systems | Palmans A.R.A.,Laboratory of Macromolecular and Organic Chemistry | And 8 more authors.
Journal of Physical Chemistry B | Year: 2010

Understanding the molecular mechanism of cooperative self-assembly is a key component in the design of self-assembled supramolecular architectures across multiple length scales with defined function and composition. In this work, we use density functional theory to rationalize the experimentally observed cooperative growth of C3-symmetrical trialkylbenzene-1,3,5- tricarboxamide-(BTA-) based supramolecular polymers that selfassemble into ordered one-dimensional supramolecular structures through hydrogen bonding. Our analysis shows that the cooperative growth of these structures is caused by electrostatic interactions and nonadditive effects brought about by redistribution of the electron density with aggregate length. © 2010 American Chemical Societ.


Filonenko G.A.,Schuit Institute of Catalysis | Filonenko G.A.,TU Eindhoven | Cosimi E.,Royal DSM | Lefort L.,Royal DSM | And 7 more authors.
ACS Catalysis | Year: 2014

Lutidine-derived bis-N-heterocyclic carbene (NHC) ruthenium CNC-pincer complexes (Ru-CNC's) were prepared. Depending on the synthetic procedure, normal (1, 2) or mixed normal/abnormal NHC-complexes (3) are formed. In the presence of phosphazene base, Ru-CNC complexes activate nitriles to give ketimino compounds 4-6. Nitrile adduct 4 shows reactivity toward strong bases to yield dearomatized complex 7, which heterolytically activates H2 to form the bis-hydrido complex 8. Finally, these Ru-CNC's are active in catalytic hydrogenation of CO2 to formate salts, and unlike the phosphine-containing Ru-PNP counterpart, they also catalyze the selective hydrogenation of esters to alcohols. © 2014 American Chemical Society.


Hensen E.,Schuit Institute of Catalysis | Dugulan I.A.I.,Schuit Institute of Catalysis | Van Veen R.J.A.R.,Schuit Institute of Catalysis
ACS National Meeting Book of Abstracts | Year: 2010

A true type II 'Co-Mo-S' phase in CoMo/Al2O2 hydrotreating catalysts can be obtained by using chelating agents and high-pressure sulfidation. The small differences in sulfidation degree underlying the extent of type I/II behavior are best probed by the Mo-S coordination number. Besides, the activity in DBT HDS is more influenced by the stacking degree of the MoS2 phase than is the thiophene HDS. The most active hydrotreating catalysts should be completely sulfided and have a monolayer MoS2 morphology.

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