20 research outputs found
Catalytic low pressure hydrogenation of carbonyl compounds over Pd supported on ZnO/ZnAl2O4 catalyst
Influence of post-synthetic thermal treatments and acid leaching on the catalytic activity of H-BEA zeolite in the acylation of anisole.
Highly selective Friedel-Crafts acylation of 2-methoxynaphtalene catalyzed by H-BEA zeolite
Selective catalytic low pressure hydrogenation of acetophenone on Pd/ZnO/ZnAl2O4
A PdZn alloy-based catalyst was prepared by impregnation with a Pd salt of the oxides obtained by the thermal decomposition of a Zn-Al hydrotalcite. Two samples were obtained by carrying out the reduction at 373 and 673 K, that were characterized by chemical analysis, powder XRD and TEM. The catalytic activity was tested in the low pressure hydrogenation of acetophenone. The results were compared with those obtained using a conventional palladium catalyst
Environmentally friendly Friedel-Crafts acylation of 2-methoxynaphtalene catalyzed by beta zeolite
Synthesis by neutral templating and structural characterization of Si/Sn mesoporous molecular sieves
Surface acidity modifications induced by thermal treatments,steaming, acid leaching and silanization on microcrystalline H-BEA zeolite
Photoexcited triplets of dyes in zeolitic nanostructured channels. A Time Resolved EPR study
Two dyes (4-nitrostilbene, NST and 4-N,N-dimethylamino-40-nitrostilbene, DANS) included in
zeolites with nanometric channels and different Si : Al ratios have been photoexcited and their
triplet state studied by time resolved EPR (TR-EPR). This is the first time that a TR-EPR
spectrum of photoexcited triplet states of dyes in zeolites has been observed. The zeolites used
were ZSM-5 and mordenite, with either protons or lithium as charge compensating ions, and the
aluminium-free porosil. The ZFS parameters and the polarized spin populations have been
obtained, and compared with those obtained in glassy solutions and in the organic
nanostructured matrix perhydrotriphenylene (PHTP). For 3DANS in neutral solvents and in
PHTP the dimethylamino group is p conjugated, whereas only its acid form is detected in all the
zeolites. In the latter the spectra of the radical cations formed by spontaneous oxidation have also
been observed both by cw-EPR and TR-EPR, the last spectra being spin polarized in emission.
The mobility of the triplets is discussed, taking into account the spin polarization of the radical
cations indicating a strong radical–triplet interaction