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

Investigation of amyloid aggregate formation in various protein systems

This thesis investigates the self assembly of rod-like aggregates termed <i>amyloid fibrils </i>and higher ordered spherical aggregates known as <i>spherulites </i>in various protein systems. The overall theme is to develop an understanding of the mechanism of formation of these structures using <i>in vitro </i>proteins for models. Four proteins in total were studied for comparison: insulin, β-lactoglobulin, hen egg white lysozyme and amyloid-β. Studies on β-lactoglobulin and hen egg white lysozyme showed that the formation of amyloid aggregates occurred on the same time scale as the degradation of the protein molecules. Defined fragment masses were observed and increased in number with increasing incubation time of the proteins. This has lead to the observation that protein degradation may play a key role in amyloid formation. Stirring insulin, β-lactoglobulin, and hen egg white lysozyme samples during incubation altered the phase state of the <i>in vitro </i>fibrils via modification of the fibril aspect ratio. Higher stirring rates led to shorter fibrils and lower amounts of liquid crystallinity. This technique can prevent spherulites from forming and instead form aligned amyloid fibrils producing liquid-crystal like regions. Amyloid-β(1-40) and (1-42) has the ability to form spherulites <i>in vitro </i>under very specific conditions. This is the first observation of spherulites in this peptide which resemble those that readily form in insulin, β-lactoglobulin and hen egg white lysozyme which show the characteristic Maltese cross pattern when viewed between crossed polarisers. Finally, the secondary structure of spherulites formed in insulin, β-lactoglobulin and amyloid-β(1-40) was studied using Raman spectroscopy. This has shown direct similarities between insulin and amyloid-β(1-40). Both show a core which contains a higher proportion of amorphous material, with fibrils that grow radially from the core. BLG spherulites have a less well defined core, the fibrils which twist as they radiate from the centre.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Oxidative Methanol Steam Reforming (OSRM) on a PdZnAl hydrotalcite derived catalyst

Catalytic systems for the oxidative methanol reforming (OSMR) with a 1% and 2% metal loading were prepared impregnating the spinel-oxide mixture (ZnAl2O4/ZnO) obtained by thermal decomposition of a Zn-Al hydrotalcite at 1173 K with palladium nitrate solution. The samples, after thermal treatment in reducing conditions, were characterized by TEM and XRD. The catalysts showed a quite good catalytic activity in the reaction under study with high methanol conversion and good selectivity to CO2. The high activity and selectivity were attributed to the prevailing presence, on the catalyst surface, of a highly dispersed 1:1 PdZn alloy phase