highly active metallocenes and other single site catalysts have opened up the possibility of polymerizing cycloolefins such as norbornene (n) or of copolymerizing them with ethene (e) or propene (p). the polymers obtained show exciting structures and properties. e-n copolymers are industrially produced materials, with variable and high glass transitions depending on the wide range of their micr...

fischer-tropsch catalysts with high activity and selectivity for olefins were produced using mordenite type sio2/al2o3= 12, 20, 28, 62 zeolite supported iron carbonyl compounds and were characterized by x-ray powder diffraction. the adsorptionof volatile fe(co)5 on the support surface was carried out under vacuum at room temperature. reduction les were monitored by vibrating sample magnetometer...

The aim within this project was to optimise the CO oxidation over TiO2 supported gold catalysts, focusing on two different preparation methods; deposition precipitation (DP) and photodeposition (PD), using different types of TiO2 and varying the theoretical gold loading. The catalyst were characterised with TEM (size) and ICP-AES (loading). For DP catalysts, the support is important for high ac...

bioleaching of spent refinery processing catalysts using adapted indigenous strains ofacidithiobacillus ferrooxidans to recover ni and mo, and the separation of ni from bioleaching liquor usingiron magnetic nanoparticles were optimized in this study. bioleaching optimization was performed usingcentral composite design (ccd) method to optimize temperature (32 to 38oc), initial ph (1.5 to 2), par...

in this study we have tested the ability of a standard dft computational protocol to reproduce the experimentally obtained stereoselectivity of 26 different c2-symmetric zirconocene catalysts active in propylene polymerization. the catalysts were chosen for their relevance in metallocene catalyzed polymerization of propylene. to this end, primary insertion of both si- and re-propylene enantiofa...

beside ziegler-natta and phillips catalysts the development of methylaluminoxane (mao) as cocatalyst incombination with metallocenes or other transition metal complexes for the polymerization of olefins haswidely increased the possibilities in controlling the polymer composition, polymer structure, tacticity and special properties with high precision. these catalysts allow the synthesis of isot...

accelerated deactivation of co/al2o3 catalysts in fischer-tropsch synthesis and the effect of re and ru as the catalytic promoters are reported. 15wt% co/al2o3 catalyst and 1wt% ru and 1.4wt% re  promoted cobalt catalysts have been formulated and extensively characterized. the deactivation of the unpromoted cobalt catalyst and those promoted with re and ru were studied by accelerated method at ...

Metallic nanoparticles are emerging as an exciting class of heterogeneous catalysts with the potential advantages of exceptional activity, stability, recyclability, and easier separation than homogeneous catalysts. The traditional colloid nanoparticle syntheses usually involve strong surface binding ligands that could passivate the surface active sites and result in poor catalytic activity. The...

The Grubbs' first and second generation catalysts were occluded into cross-linked slabs of polydimethylsiloxane with volumes from 1 mm3 to 1 cm3 by swelling the polymer with catalyst and methylene chloride. Methylene chloride was evaporated under vacuum to yield occluded catalysts where their solvent was polydimethylsiloxane. These occluded catalysts were reacted with alkenes dissolved in H2O o...

Increased oxygen reduction reaction (ORR) kinetics, improved CO tolerance, and more efficient water and heat management represent significant advantages that high-temperature polymer electrolyte fuel cells (HT-PEFCs) operating with a phosphoric acid-doped polybenzimidazole (PBI) membrane offer over traditional Nafion-based, low-temperature PEFCs. However, before such HT-PEFCs become viable, the...