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Qian Zhao,Qian Wang,Duolin Wu,Xiaoqi Fu,Tingshun Jiang,Hengbo Yin 한국공업화학회 2012 Journal of Industrial and Engineering Chemistry Vol.18 No.4
Several SO42-/Zr-MCM-41 and SO42-/Zr-MCM-48 solid acid catalysts were prepared by wet impregnation method and were characterized by FT-IR, XRD, NH3-TPD and N2 physical adsorption,respectively. The catalytic activities of these catalysts were evaluated in alkylation reaction of phenol and tert-butyl alcohol. Experimental results reveal that the four solid acid catalysts still maintained a typical mesoporous framework. Under comparable condition, the SO42-/Zr-MCM-48-25 catalyst exhibits much high catalytic activity and gives the highest phenol conversion as compared with the other catalysts. A maximum phenol conversion of 91.6% with 81.8% selectivity to 4-tert-butylphenol (4-TBP) was achieved at the reaction temperature of 140 8C. 2012 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.
Effects of La_2O-3 on ZrO-2 supported Ni catalysts for autothermal reforming of CH_4
Sun Hee Park,김성현,전병희 한국화학공학회 2011 Korean Journal of Chemical Engineering Vol.28 No.2
The effect of La_2O_3 content in Ni-La-Zr catalyst was investigated for the autothermal reforming (ATR)of CH4. The catalysts were prepared by the coprecipitation method and had a mesoporous structure. Temperature programmed reduction (TPR) and X-ray photoelectron spectroscopy (XPS) indicated that a strong interaction developed between Ni species and the support with the addition of La_2O_3. Thermogravimetric analysis (TGA) and H2-pulse chemisorption showed that the addition of La_2O_3 led to well dispersed NiO molecules on the support. Ni-La-Zr catalysts gave much higher CH_4 conversion than Ni-Zr catalyst. The Ni-La-Zr containing 3.2 wt% La_2O-3 showed the highest activity. The optimum conditions for maximal CH_4 conversion and H_2 yield were H_2O/CH4=1.00, O_2/CH_4=0.75. Under these conditions, CH_4 conversion of 83% was achieved at 700 ℃. In excess O_2 (O_2/CH_4>0.88), the catalytic activity was decreased due to sintering of the catalyst.
Noh, Seok-Kyun,Jiang, Wen-Long The Polymer Society of Korea 2004 Macromolecular Research Vol.12 No.1
We have prepared the polymethylene-bridged, dinuciear, half-sandwich constrained geometry catalysts (CGC)[Zr(η$\^$5/:η$^1$-C$\_$9/H$\_$5/SiMe$_2$NCMe$_3$)]$_2$[(CH$_2$)$\_$n/][n=6(9), n=12(10)]by treating 2 equivalents of ZrCl$_4$with the corresponding tetralithium salts of the ligands in toluene. $^1$H and $\^$13/C NMR spectra of the synthesized complexes provide firm evidence for the anticipated dinuciear structure. In $^1$H NMR spectra, two singlets representing the methyl group protons bonded at the Si atom of the CGC are present at 0.88 and 0.64 ppm, which are considerably downfield positions relative to the shifts of 0.02 and 0.05 ppm of the corresponding ligands. To investigate the catalytic behavior of the prepared dinuciear catalysts, we conducted copolymerizations of ethylene and styrene in the presence of MMAO. The prime observation is that the two dinuclear CGCs 9 and 10 are not efficient for copo-lymerization, which definitely distinguishes them from the corresponding titanium-based dinuclear CGC. These species are active catalysts, however, for ethylene homopolymerization; the activity of catalyst 10, which contains a 12-methylene bridge, is larger than that of 9 (6-methylene bridge), which indicates that the presence of the longer bridge between the two active sites contributes more effectively to facilitate the polymerization activity of the dinuciear CGC. The activities increase as the polymerization temperature increases from 40 to 70$^{\circ}C$. On the other hand, the molecular weights of the polyethylenes are reduced when the polymerization temperature is increased. We observe that dinuciear metallocenes having different-length bridges give different polymerization results, which reconfirms the significant role that the nature of the bridging ligand has in controlling the polymerization properties of dinuclear catalysts.
Hamid Reza Safaei,Mohsen Shekouhy,Shima Khademi,Vahid Rahmanian,Maryam Safaei 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.5
A highly efficient and environmentally benign procedure for the synthesis of quinazoline derivatives via the condensation of carbonyl compounds with 2-aminobenzamide using zirconium tetrakis(dodecyl-sulfate) [Zr(DS)4] as a highly efficient, reusable Lewis acid-surfactant-combined catalyst is described. A broad range of substrates including aldehydes and ketones are successfully condensed with 2-aminobenzamide and all reactions are completed in short times and the products are obtained in good to excellent yields. The catalyst could be recycled and reused several times without any loss of efficiency. Moreover, presented procedure has been applied successfully for the synthesis of spiro-quinazolinones and fused ring-quinazolinone derivatives.
김효진,유영우,허일정,장태선,홍지숙,이기봉,서정권 한국청정기술학회 2017 청정기술 Vol.24 No.3
To verify the viability of Co, Ru and Zr-based catalyst for CO2 (dry) reforming reaction, catalysts were fabricated using cordierite, silicon carbide and rota monolithic substrates, and they were compared with the conventional Co-Ru-Zr/SiO2 catalyst in terms of performance and durability. Cordierite monolith was showed high activity with the least amount of active component. In addition, when Cordierite monolith was coated with Co-Ru-Zr in various ways, most excellent performance was showed at a precursor solution coating method. In particular, when 0.9 wt% Co-Ru-Zr/Cordierite was used for reaction, it was observed that 95% CO2 conversion was maintained for 300 h at 900 ℃.
Kim, Hyojin,You, Young-Woo,Heo, Iljeong,Chang, Tae-Sun,Hong, Ji Sook,Lee, Ki Bong,Suh, Jeong Kwon The Korean Society of Clean Technology 2017 청정기술 Vol.23 No.3
To verify the viability of Co, Ru and Zr-based catalyst for $CO_2$ (dry) reforming reaction, catalysts were fabricated using cordierite, silicon carbide and rota monolithic substrates, and they were compared with the conventional $Co-Ru-Zr/SiO_2$ catalyst in terms of performance and durability. Cordierite monolith was showed high activity with the least amount of active component. In addition, when Cordierite monolith was coated with Co-Ru-Zr in various ways, most excellent performance was showed at a precursor solution coating method. In particular, when 0.9 wt% Co-Ru-Zr/Cordierite was used for reaction, it was observed that 95% $CO_2$ conversion was maintained for 300 h at $900^{\circ}C$.
Cho, Hyun Yong,Tarte, Naresh Hiraral,Cui, Liqiang,Hong, Dae Sik,Woo, Seong Ihl,Gong, Young-Dae WILEY-VCH Verlag 2006 Macromolecular chemistry and physics Vol.207 No.21
<P>Summary: A novel non-metallocene Zr(IV) complex bearing a bianionic form of the ligand 2,6-bis(2-benzimidazolyl)pyridine is synthesized. This Zr complex is an active catalyst for the polymerization of MA via coordination polymerization in the presence of methylaluminoxane MAO. The activity and MWD are increased as the polymerization temperature increases. The maximum activity is observed at Al/Zr molar ratio of 100 and the deactivation is shown above 100, resulting from an inactive bimetallic complex between catalyst and free TMA presented in MAO. Decrease in MWD is observed with higher MAO concentration due to its role in chain transfer during the chain propagation.</P><P> <img src='wiley_img/10221352-2006-207-21-MACP200600395-gra001.gif' alt='wiley_img/10221352-2006-207-21-MACP200600395-gra001'> Graphic The reaction of the ligand and catalyst synthesis. </P>