نتایج جستجو برای: catalysts

تعداد نتایج: 32940  

2008
H. L. Xie Y. X. Fan C. H. Zhou Z. X. Du E. Z. Min Z. H. Ge X. N. Lia

The epoxidation reaction using heterogeneous solid catalysts with H2O2 as oxidants are environmentally friendly routes to produce extensively useful epoxides which are traditionally obtained from capital-intensive or environmentally polluted processes. In this paper, various types of solid catalysts for the epoxidation of olefins with H2O2 as oxidants are reviewed. The efficient catalysts repor...

2007
L. Kustov K. Egeblad M. Kustova T. W. Hansen C. H. Christensen

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...

Journal: Polyolefins Journal 2017

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...

Journal: :polyolefins journal 2016
goond hongmanee patchanee chammingkwan toshiaki taniike minoru terano

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...

2014
Hwei Voon Lee Joon Ching Juan Nurul Fitriyah Binti Abdullah Rabiah Nizah MF Yun Hin Taufiq-Yap

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...

Journal: :international journal of nanoscience and nanotechnology 2008
z. ahmadi sh. afshar l. vafaee a. salehi

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...

Journal: :iranian journal of catalysis 2016
seyed ali hosseini

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% ...

2017
Wei Wang Caleb F Anderson Zongyuan Wang Wei Wu Honggang Cui Chang-Jun Liu

Noble metal catalysts have been widely used in many applications because of their high activity and selectivity. However, a controllable preparation of noble metal catalysts still remains as a significant challenge. To overcome this challenge, peptide templates can play a critical role in the controllable syntheses of catalysts owing to their flexible binding with specific metallic surfaces and...

Journal: :Chemical science 2017
Shuang Yang Wen Che Hui-Ling Wu Shou-Fei Zhu Qi-Lin Zhou

We developed neutral iridium catalysts with chiral spiro phosphine-carboxy ligands (SpiroCAP) for asymmetric hydrogenation of unsaturated carboxylic acids. Different from the cationic Crabtree-type catalysts, the iridium catalysts with chiral spiro phosphine-carboxy ligands are neutral and do not require the use of a tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (BArF-) counterion, which is ne...

2015
Kyle M. Brunner Baiyu Huang Brian F. Woodfield William C. Hecker

A novel, solvent-deficient precipitation (SDP) method for catalyst preparation in general and for preparation of iron FT catalysts in particular is reported. Eight catalysts using a 23 factorial design of experiments to identify the key preparation variables were prepared. The catalysts were characterized by electron microprobe, N2 adsorption, TEM, XRD, and ICP. Results show that the morphology...

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