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 ...

In this study, silica nanoparticles were used as support to prepare a new heterogeneous catalyst system for application in organic reactions. The reaction of silica nanoparticles with sodium 2-bromoethane-1-sulfonate resulted in the connection of a sulfonic acid group on the surface of silica nanoparticles (NSESA). The synthetic catalyst system was characterized using different microscopic and ...

Abstract In this study , palladium nano-particles were electro deposited galvano - statically on carbon black powder (Vulcan XC -72R). The catalytic activity for electro - oxidation of ethanol and methanol in alkaline media were studied by cyclic voltammetry and linear sweep voltammetry techniques. The results indicated that the electro-oxidation of ethanol and methanol strongly depends o...

The Tetrahymena ribozyme possesses peripheral domains, termed P9.1 and P9.2. They are nonessential in the mechanism of the catalytic reaction but contribute to enhance the catalytic activity of the ribozyme. It has been postulated that P9.1 is capable of forming Watson-Crick base pairings with another peripheral domain, P2.1. We report here the existence of long-range base pairings between the ...

Adenine-dependent hairpin ribozymes were isolated by in vitro selection from a degenerated hairpin ribozyme population. Two new adenine-dependent ribozymes catalyze their own reversible cleavage in the presence of free adenine. Both aptamers have Mg(2+) requirements for adenine-assisted cleavage similar to the wild-type hairpin ribozyme. Cleavage kinetics studies in the presence of various othe...

Allosteric modulation of catalysis kinetics is prevalent in proteins and has been rationally designed for ribozymes. Here, we present an allosteric DNA molecule that, in its active configuration, catalyzes a noncovalent DNA reaction. The catalytic activity is designed to be modulated by the relative concentrations of two DNA regulator molecules, one an inhibitor and the other an activator. Dyna...

The mechanism by which RNA molecules assemble into unique three-dimensional conformations is important for understanding their function, regulation and interactions with substrates. The Tetrahymena group I ribozyme is an excellent model system for understanding RNA folding mechanisms, because the catalytic activity of the native RNA is easily measured. Folding of the Tetrahymena ribozyme is dom...

An efficient synthetic method for successful synthesis of amine denderon on SBA-15 and related Pd (II) complex has been developed. This modified mesoporous material was characterized by various techniques such as TEM, XRD, atomic absorption spectroscopy, N2 adsorption-desorption, and FT-IR. The catalytic activities of the prepared catalysts were investigated by employing aerobic oxidation of al...

cui nanoparticles as an expedient and recyclable catalyst for the synthesis of n-cyclohexyl-3-aryl-quinoxaline-2-amines in ethanol via a multi-component reaction are established. the products were separated from the catalyst simply by filtration. the catalyst could be recycled and reused for several times without noticeably decreasing the catalytic activity.