A novel imido-modified SiO2-supported Ti/Mg Ziegler-Natta catalyst for ethylene and ethylene/1-hexene polymerization is investigated. The catalyst is prepared by modification of (SiO2/MgO/MgCl2)TiClx Ziegler-Natta catalysts via supporting vanadium species followed by reaction with p-tolyl isocyanate as imido agents, to get the merits from both the SiO2-supported imido vanadium catalyst and the ...

In this study, the effect of preparation technique of carbon nanotube (CNT)-supported cobalt catalysts on the activity and selectivity of Fischer-Tropsch synthesis (FTS) was studied. Different concentrations of acetic acid were used for the pretreatment of the catalyst support to modify the surface properties of CNT. This modification improved the reduction degree and dispersion of supported co...

hantzsch 1,4-dihydropyridines are oxidized to the corresponding pyridine derivatives using oxygen or air and a mixture of the manganese and cobalt salts of parninobenzoic acid supported on silica gel as the catalysts. reactions are clean and the catalysts can be recovered easily and reused repeatedly.

An extensive series of supported WO3/ZrOx (OH)4−2x catalysts (WZrOH) were synthesized by standard aqueous impregnation of ammonium metatungstate into an amorphous ZrOx (OH)4−2x metastable support, followed by high-temperature calcination (at 773–1173 K). The supported WZrOH catalysts were also compared with well-defined model supported WO3/ZrO2 catalysts (WZrO2) consisting of a thermally stable...

Homogeneous molecular catalysts are immobilzed in a well-defined fashion on individual silica nanoparticles with a narrow particle size distribution by covalent attachment. This synthetic methodology is demonstrated with modified salicylaldiminato-substituted titanium(IV) complexes incorporating a trimethoxysilaneterminated linker: dichloro-bis[κ2-N,O-6-(3-(trimethoxysilyl)propoxyphenylimino)-2...

bis(2-r-ind)zrcl2 (r: h or phenyl) was supported on different types of silica by in situ impregnation method and used for ethylene polymerization. in this method, the step of catalyst loading on support was eliminated and common alkyl aluminum (triisobutylaluminum, tiba) cocatalyst was used instead of expensive methyl aluminiumoxane (mao) cocatalyst in the polymerization. the effect of surface ...

The synthesis of supported palladium (Pd) catalysts is reviewed with emphasis on the chemistry of catalyst synthesis, oxidic and carbon support properties and case studies in the period 1990-2000. For the application of Pd onto oxidic supports aqueous precursor solutions are frequently used. The charge of the Pd precursor and the iso-electric point of the support are important properties since ...