in a novel dual bed reactor fischer-tropsch synthesis was studied by using two diffrent cobalt catalysts. an alkali-promoted cobalt catalyst was used in the first bed of a fixed-bed reactor followed by a rutenuim promoted cobalt catalyst in the second bed. the activity, product selectivity and accelerated deactivation of the system were assessed and compared with a conventional single bed react...

mgcl2/c2h5oh adducts with constant relative ratio of 1/3 were prepared and kept at 120oc for different lengths of times of 5, 10, 20, 30, 50, 90,120 and 220 h. then the samples were quenched and analyzed by xrd and bet. no meaningful changes were observed in the specific surface area of the samples, while xrd spectra showed 3 peaks at 2θ<15o for samples kept at 120oc for 5 h. these 3 peaks were...

mg(oet)2 with spherical morphology is one of the most important precursors for the preparation of industrialziegler-natta catalysts. in the present article, morphology evolution of mg(oet)2 particles is studied in the courseof the synthesis. the morphology of mg(oet)2 particles is observed throughout the process by sem. the resultsshow that mg(oet)2 particles are formed through i) seed generati...

Water-soluble single-component (kappa2-N,O)-salicylaldiminato nickel-methyl complexes 1-4-L (L = TPPTS, TPPDS, H2N-PEG-OMe) allow for the catalytic polymerization of ethylene under organic solvent-free aqueous conditions producing high molecular weight polyethylene with particle sizes below 10 nm. Amphiphilic TPPDS- and H2N-PEG-OMe complexes exhibit a polymerization activity in water higher tha...

the interaction of the external donor (propyltrimethoxysilane - ptms) with titanium-magnesium catalysts (tmcs) containing dibutylphthalate (dbp) as internal donor, which were prepared in different ways, was studied by chemical analysis and infrared diffuse reflectance spectroscopy (drifts). the chemical composition of the catalysts after their interaction with heptane solutions of ptms, ptms/al...

Understanding the kinetics of olefin polymerization with Ziegler-Natta and related catalysts means identifying the main kinetic parameters such as k(p) and concentration of active sites. The high-pressure quenched-flow technique could be an absolute method for counting active sites and for activation studies of molecular catalysts. A kinetic study of metallocene catalysts and a phenoxy-imine ti...