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 ...

in this research iron manganese oxide nanocomposites were prepared by co-precipitation, sol-gel and mechanochemical methods by using iron (iii) nitrate, iron (ii) sulfate and manganese (ii) nitrate as starting materials. these nanocomposites were prepared in the presence of various catalyst beds. the polyvinyl pyrrolidon (pvp) was used as a capping agent to control the agglomeration of the nano...

dodecylbenzenesulfonic acid (dbsa) was used as an efficient, cheap and stable brønsted catalyst for acetylation of alcohols and phenols and formylation of alcohols under solvent-free conditions. various primary, secondary and tertiary alcohols were acetylated with acetic anhydride as an acetylating agent under solvent-free conditions in the presence of catalytic amount of dbsa at room temperatu...

By coupling of Fe2O3@SiO2 particles with metal organic Framework (MOF) the magnetic MOF structure was fabricated. Precipitation and hydrothermal methods were applied for synthesis of core and MOF. Silver nanoparticles were deposited on nickel based metal organic framework surface and magnetic Fe2O3@SiO2@MOF@Ag was obtained. Because of strong coupling between silver nanoparticles and metal organ...

Background: Considering natural thermal stability, Geobacillus stearothermophilus amylase and Cel5E from Clostridium thermocellum are good candidates for industrial applications. To be compatible with the industrial applications, this enzyme should be stable in the high temperatures, so any improvement in their thermal stability is valuable.Objectives: Us...

efficient and one-pot synthesis of 1,8-dioxo-octahydroxanthenes was described by knoevenagel condensation, michael addition and cyclodehydration of dimedone. this reaction was carried out through condensation of dimedone and various aromatic aldehydes in the presence of task-specific brønsted acidic ionic liquid under solvent free conditions. the catalyst could be recycled five times without si...

development of efficient electrocatalysts for oxygen reduction reaction (orr) is one of the most important issues for optimizing the performance of fuel cells and metal-air batteries. the introduction of nitrogen into carbon nanostructures has created new pathways for the development of non-precious electrocatalysts in fuel cells. in this work, nitrogen-doped graphene (ng) was synthesized by a ...

Phosphoryl transfer onto backbone hydroxyls is a recognized catalytic activity of nucleic acids. We find that kinase ribozyme K28 possesses an unusually complex active site that promotes (thio)phosphorylation of two residues widely separated in primary sequence. After allowing the ribozyme to radiolabel itself by phosphoryl transfer from [γ-(32)P]GTP, DNAzyme-mediated cleavage yielded two radio...

Nanoporous sodium montmorillonite clay (Na+-MMT) was used as a support for the immobilization of 1-methyl-3-(trimethoxysilylpropyl)-imidazolium hydrogen sulfate (Na+-MMT-[pmim]HSO4). This catalyst showed excellent catalytic activity for the preparation of 2-amino-3-cyano-5-oxo-5,6,7,8-tetrahydro-4H-benzopyrans via three-component reactions betw...