Untersuchungen an Nickeloxid‐Mischkatalysatoren. II Katalytische Eigenschaften von NiO/SiO 2 ‐Katalysatoren

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Characterization of NiSO₄Supported on Fe₂O₃and Catalytic Properties for Ethylene Dimerization

2007

“…A considerable number of papers have dealt with the problem of nickel-containing catalysts for ethylene dimerization. [1][2][3][4][5][6][7][8][9][10][11] One of the remarkable features of this catalyst system is its activity in relation to a series of n-olefins. In contrast to usual acid-type catalysts, nickel oxide on silica or silicaalumina shows a higher activity for a lower olefin dimerization, particularly for ethylene.…”

Section: Introcuctionmentioning

confidence: 99%

“…In contrast to usual acid-type catalysts, nickel oxide on silica or silicaalumina shows a higher activity for a lower olefin dimerization, particularly for ethylene. [1][2][3][4][5][6]12 It has been suggested that the active site for dimerization is formed by an interaction of a low-valent nickel ion with an acid site. 9,13 In fact, nickel oxide, which is active for C 2 H 4 -C 2 D 4 equilibration, acquires an activity for ethylene dimerization upon addition of nickel sulfate, which is known to be an acid.…”

Section: Introcuctionmentioning

confidence: 99%

Effect of Al₂O₃Addition and WO₃Modification on Catalytic Activity of NiO/Al₂O₃-TiO₂/WO₃for Ethylene Dimerization

Pae¹,

Sohn

2007

Strong solid acid catalysts, NiO/Al 2 O 3 -TiO 2 /WO 3 for ethylene dimerization were prepared by the addition of Al 2 O 3 and the modification with WO 3 . The acid sites and acid strength were increased by the inductive effect of WO 3 species bonded to the surface of catalysts. The larger the dispersed WO 3 amount, the higher both the acidity and catalytic activity for ethylene dimerization. The addition of Al 2 O 3 to TiO 2 up to 5 mol% enhanced acidity and catalytic activity gradually due to the interaction between Al 2 O 3 and TiO 2 and consequent formation of Al-O-Ti bond.Key Words : Al 2 O 3 addition, WO 3 modification, Acidity, Ethylene dimerization IntrocuctionHeterogeneous catalysts for the dimerization and oligomerization of olefins, consisting mainly of nickel compounds supported on oxides, have been known for many years. A considerable number of papers have dealt with the problem of nickel-containing catalysts for ethylene dimerization.

“…A considerable number of papers have dealt with the nickel-containing catalysts for ethylene dimerization. 17,[20][21][22][23][24][25][26][27][28] One of the remarkable features of this catalyst system is its activity in relation to a series of n-olefins. In contrast to usual acid-type catalysts, nickel oxide on silica or silica-alumina shows a higher activity for a lower olefin dimerization, particularly for ethylene.…”

Section: Introductionmentioning

confidence: 99%

CeO2-Promoted Highly Active Catalyst, NiSO4/CeO2-ZrO2 for Ethylene Dimerization

2006

The NiSO4/CeO2-ZrO2 catalysts containing different nickel sulfate and CeO2 contents were prepared by the impregnation method, where support, CeO2-ZrO2 was prepared by the coprecipitation method using a mixed aqueous solution of zirconium oxychloride and cerium nitrate solution followed by adding an aqueous ammonia solution. No diffraction line of nickel sulfate was observed up to 20 wt %, indicating good dispersion of nickel sulfate on the surface of CeO2-ZrO2. The addition of nickel sulfate (or CeO2) to ZrO2 shifted the phase transition of ZrO2 from amorphous to tetragonal to higher temperatures because of the interaction between nickel sulfate (or CeO2) and ZrO2. A catalyst (10-NiSO4/1-CeO2-ZrO2) containing 10 wt % NiSO4 and 1 mole % CeO2, and calcined at 600 °C exhibited a maximum catalytic activity for ethylene dimerization. The catalytic activities were correlated with the acidity of catalysts measured by the ammonia chemisorption method. The role of CeO2 was to form a thermally stable solid solution with zirconia and consequently to give high surface area, thermal stability and acidity of the sample.