12-Tungstophosphoric acid supported on silica-coated magnetic nano particles was prepared and characterized by transmission electron microscopy, scanning electron microscopy, powder X-ray diffraction and inductively coupled plasma atomic emission spectroscopy. Acidity of the catalysts was measured by potentiometric titration with n-butylamine. Catalytic activity of the prepared sample was evalu...

The surface chemistry of adsorbed isopropoxy groups on supported vanadia–alumina and vanadia–silica catalysts was investigated with multiple in situ spectroscopic techniques. The in situ FT-IR, Raman and UV–vis spectroscopic measurements provided molecular level information about the surface intermediates and the surface vanadium oxide species as a function of different conditions. The spectros...

The principles of infrared emission spectroscopy are briefly reviewed with emphasis on the aspects of its application to the study of chemisorbed species. The ma in problems of sample preparation, selection of measurement conditions and the most suitable methods of data treatment are discussed. IR emittance spectra of two typical support materials for supported metal catalysts, aJumina and sili...

A general and efficient approach toward new zirconium and hafnium complexes based on 2-aryl-8-arylaminoquinoline ligands was developed. These precursors, when activated with MAO/borate cocatalyst and supported on silica, result in active olefin polymerization catalysts. The ethylene copolymers produced under industrially relevant conditions show very high molecular weights and unique microstruc...

Selective acylation of alcohol has enjoyed great attraction of chemists due to its significance in synthetic organic chemistry especially in protecting group chemistry as reflected by the number of methods that have been developed to effect this transformation. To meet the challenging task of chemoselective transformation of aliphatic alcohols in the presence of phenolic alcohol mainly acidic c...

A convenient and efficient methodology for the synthesis of densely substituted pyrrole-fused isocoumarins, which employs solid-supported silica sulfuric acid (SSA) as catalyst, has been developed. When the mixture of ninhydrin adducts of acetylacetone/ethyl acetoacetate and primary amines was heated on the solid surface of SSA under solvent-free conditions, the pyrrole-fused isocoumarins were ...

Hybridisation of mesoporous organosilicas (MO) to reinforce the surface capability in adsorption and stabilisation noble metal nanoparticles is great attention generating/supporting within their matrices transforming them into efficient heterogeneous catalysts. Here, we used a unique hybrid organic-inorganic silica which pore profile pattern was similar well-known silica, SBA-15 for catalysis. ...

heterogeneous ziegler-natta and homogeneous metallocene catalysts exhibit greatly different active sitenature in olefin polymerization. in our previous study, it was reported that mgcl2-supported titanocenecatalysts can generate both ziegler-natta-type and metallocene-type active sites according to the type of activators.the dual active site nature of the supported titanocene catalysts was furt...

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 ...

Deposition of CH3ReO3 onto the surface of dehydrated, amorphous silica-alumina generates a highly active, supported catalyst for the metathesis of olefins. However, silica-alumina with a high (10 wt %) Re loading is no more active than silica-alumina with low (1 wt %) loading, while CH3ReO3 on silica is completely inactive. Catalysts prepared by grafting CH3ReO3 on silica-alumina contain two ty...