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 Suzuki-Miyaura cross-coupling reaction of 1-aryltriazenes with arylboronic acids catalyzed by a recyclable polymer-supported Pd-NHC complex catalyst has been realized for the first time. The polymer-supported catalyst can be re-used several times still retaining high activity for this transformation. Various aryltriazenes were investigated as electrophilic substrates at room temperature to ...

Macroporous polymer supported nanoparticles of copper(I) iodide catalyst and macroporous polymer supported azide reagent were used to simplify the synthesis of 1,4-disubstituted-1H-1,2,3-triazoles from various benzyl halides following the green chemistry principles. This new one-pot protocol facilitates the workup of the reaction and provides the products in short times and at high yields. Hete...

I n this issue of PNAS, Schoonheydt, Solomon, and coworkers (1) definitively characterize the structure of the Cu-ZSM-5 site that oxidizes methane to methanol. With the successful correlation of a specific copper-oxy structure to such reactivity, the importance of this work extends beyond hydrocarbon oxidation on zeolites. This breakthrough potentially has farreaching implications in both the f...

Heterogeneous rhodium catalysts supported on SiO2 were modified with PPh3 for the gas-phase hydroformylation of propene to produce nand isobutanal. High selectivity to aldehydes was achieved, with no propane or alcohols formed. Investigation of the effects of reaction temperature, reactant partial pressures, total pressure, and PPh3/Rh ratio suggested that the supported catalyst behaved similar...

The eggshell is an important physiological structure for the embryo. It enables gas exchange, physical protection and is a calcium reserve. Most squamates (lizards, snakes, worm lizards) lay parchment-shelled eggs, whereas only some gekkotan species, a subgroup of lizards, have strongly calcified eggshells. In viviparous (live-bearing) squamates the eggshell is reduced or completely missing (he...

In the present study, the synthesis of diethylene triamine supported on cellulose biopolymer as a biodegradable solid basic heterogeneous catalyst was suggested. Then, the applicability of the synthesized catalyst cellulose bonded N-propyl diethylene triamine (CBPDETA) was tested for the synthesis of oxindole derivatives, an important class of potentially bioactive compounds. A various series o...

Using wet impregnation method, a novel ternary system of silica supported Fe-Co-Ce catalyst was prepared. Preparation conditions such as impregnation time and temperature, drying time and temperature, were optimized by the L9 Taguchi experimental design to achieve a light olefin selective catalyst with maximum CO conversion in a fixed bed micro-reactor. It was found that the best conditions to ...

A novel generic method of silica supported catalyst system generation from a fluid state is presented. The technique is based on the combined flow and radiation (such as microwave, thermal or UV) induced co-assembly of the support and catalyst precursors forming nano-reactors, followed by catalyst precursor decomposition. The transformation from the precursor to supported catalyst oxide state c...

Laser-Raman and infrared spectroscopic studies reveal abundant beta-pleated sheet conformation in the eggshell proteins of the fish Salmo gairdneri. This secondary structure is the underlying molecular conformation, dictating the formation of the helicoidal architecture of the eggshell. Disulphide bonds crosslink the eggshell proteins of the fertilized eggs and are apparently found in g-g-g (ga...