Chromium is a trace metal of importance in human physiology and, in addition, as 51-chromate, has been extensively used as a label in the study of blood cell pool sizes and intravascular kinetics. The transport characteristics of 51-chromate were investigated in normal human leukocytes. Chromate uptake is unidirectional over a 1 hr incubation with extracellular chromate concentrations up to 200...

Development of new chemical processes using CO2 as raw material has become a high priority for scientists. Utilisation of CO2 as feedstock would have the advantages of being naturally occurring, abundant, and inexpensive. However, due to the thermodynamic and kinetic stability of CO2 its activation represents a challenge for chemists. In this context, the low reactivity of CO2 can be overcome b...

The development of the first highly active enantioselective catalyst for the aza-Claisen rearrangement of Z-configured allylic trifluoroacetimidates generating valuable almost enantiopure protected allylic amines is described. Usually Z-configured allylic imidates react significantly slower than their E-configured counterparts, but in the present study the opposite effect was observed. Z-Config...

The reaction of a silyl dienolate, Cu(II) salt and TBAT yielding the corresponding copper dienolate is addressed. A combined NMR cyclic voltammetry analysis first highlight role in to Cu(I) reduction structure precatalytic species. From these results second set theoretical studies enable determination mechanism formation catalytic Finally, we showed that catalyst promote E/Z s-cis/s-trans equil...

Silicones are typically cured at room temperature by means of metal catalyst such as tin or platinum. When networks formed, the becomes unrecoverable, which is economic well environmental concern. Very few methods for producing catalyst-free room-temperature-vulcanized (RTV) silicones exist and require conditions unavailable in industrial settings. Through study organic polysilazane (PSz) react...

An efficient method for the synthesis of mono and bulky 1,8-dioxooctahydroxanthenes was developed by the reaction of dimedone or 1,3-cyclohexadione and aldehydes or some bisaldehydes in the presence of polyvinylpolypyrrolidone supported oxalic acid (PVPP-OXA) as a new polymeric catalyst in ethanol at room temperature. Polyvinylpolypyrrolidone supported oxalic acid was characterized by FT-IR, an...

group viii b metal oxides supported on gamma-alumina were investigated as catalysts and promoters of moo3 hydrodesulfurization catalysis. superior promotion was observed in pbo promoted catalyst compared to that of coo, the typically accepted promoter. other metal oxides, sno and ho2o3 exhibited reasonable hydrodesulfurization catalysis promotion but lower than for coo promoted catalyst.

Cr(VI) (chromate) is a widespread, toxic and soluble environmental contaminant. Bacteria can reduce chromate to insoluble and less toxic Cr(III), and thus chromate bioremediation is of interest. Genetic and protein engineering of suitable enzymes can improve bacterial bioremediation. However, many fundamental parameters that define an organism’s capacity to remediate chromate have not previousl...

The supported palladium nanoparticles catalyst with uniform-sized Pd particles distribution and without nitrogen or chlorine atoms present in catalyst was prepared by calcination of the supported [Pd(lysine·HCl)(Cl)2] complex as precursor and characterized by TEM. Moreover the supported [Pd(lysine·HCl)(Cl)2] complex was from cation exchanging [Pd(lysine·HCl)(Cl)2] complex with inorganic support...

Cr(VI) (chromate) is a toxic, soluble environmental contaminant. Bacteria can reduce chromate to the insoluble and less toxic Cr(III), and thus chromate bioremediation is of interest. Genetic and protein engineering of suitable enzymes can improve bacterial bioremediation. Many bacterial enzymes catalyze one-electron reduction of chromate, generating Cr(V), which redox cycles, generating excess...