ethylene was polymerized in slurry phase over a ticl4/mg(oc2h5)2 catalyst activated by al(c2h5)3. it was shown experimentally that mass transfer resistance has no effect on polymerization kinetics. after estimation ofthe active site concentration by inhibition method with carbon monoxide, the effects of polymerization temperature, monomer and cocatalyst  oncentrations and hydrogen were investig...

ethylene was homopolymerized over ziegler-natta catalyst and the homopolymerization was modeled using moment equations. mechanism was modeled according to five different reaction centers of catalyst. for each center, there are different reaction rate coefficients; therefore the final product of each center would be expected to be different. modeling results showed good conformity to the experim...

in the present work, a titanium-based ziegler-natta catalyst was employed to synthesize ultra molecular weight polyethylene in a slurry medium. the effect of different parameters such as ethylene pressure, temperature, catalyst composition, and hydrogen pressure was studied. as the results indicate, increasing either [al]/[ti] ratio or temperature causes polymerization rate to go through a maxi...

copolymerization of ethylene and propylene was investigated using a 4th generation phthalate ziegler-natta catalyst in normal hexane in a buchi reactor. the effects of different mole fractions of [al]/[ti], [si]/[al] and various amounts of hydrogen on productivity and weight percent of ethylene on the product, were studied. in the copolymerization reactions, tri-isobutyl aluminum (tibal) was us...

Mesoporous and conventional Fe-containing ZSM-5 catalysts (0.5–8 wt% Fe) were prepared using a simple impregnation method and tested in NO selective catalytic reduction (SCR) with NH3. It was found that mesoporous Fe-ZSM-5 catalysts exhibit higher SCR activities than comparable conventional catalysts. Furthermore, conventional Fe-ZSM-5 catalysts have maximum activity at ~ 2.5 wt% Fe while for t...

Chromium-vanadium (Cr-V) bimetallic catalysts are prepared by the introduction of vanadium into the Phillips catalyst which is one of the most significant industrial ethylene polymerization catalysts for tuning the Phillips catalyst performances and improving polyethylene properties. In the present work, titanium species were introduced into the fluorine-modified chromium-vanadium bimetallic ca...

BACKGROUND Transesterification catalyzed by solid base catalyst is a brilliant technology for the noble process featuring the fast reaction under mild reacting condition in biodiesel production. Heterogeneous base catalysts are generally more reactive than solid acid catalysts which require extreme operating condition for high conversion and biodiesel yield. In the present study, synthesis of b...

in this work, tio2 /sio2 (pure anatase), and tio2 /sio2 (anatase/rutile) nano-photocatalysts are prepared by using sol-gel method and control of acidity. the particles size is calculated using scheerer, s equation and is estimated to be around 7-15 nm. in order to improve the photocatalytic activity of tio2 /sio2 ,1% (wt) platinum particles are loaded on both catalysts using photoreductive meth...

lamno3 and lamno3/zsm-5 nano catalysts were synthesized by pechini method and their physical-chemical properties were characterized using xrd, ftir, sem-edx, uv-vis drs, bet surface area and tpr. the correlation between characteristic properties and activity of catalysts were investigated. the catalytic performance of the catalysts was evaluated in combustion of 2-propanol and compared with 1% ...