NiSO_4 Supported on FeO-promoted ZrO_2 Catalyst for Ethylene Dimerization

摘要

The NiSO_4 supported on FeO-promoted ZrO_2 catalysts were prepared by the impregnation method.FeO-promoted ZrO_2 was prepared by the coprecipitation method using a mixed aqueous solution of zirconium oxychloride and iron nitrate solution followed by adding an aqueous ammonia solution.The addition of nickel sulfate (or FeO) to ZrO_2 shifted the phase transition of ZrO_2 (from amorphous to tetragonal) to higher temperatures because of the interaction between nickel sulfate (or FeO) and ZrO_2.10-NiSO_4/5-FeO-ZrO_2 containing 10 wt% NiSO_4 and 5 mol % FeO,and calcined at 500 deg C exhibited a maximum catalytic activity for ethylene dimerization.NiSO_4/FeO-ZrO_2 catalysts was very effective for ethylene dimerization even at room temperature,but FeO-ZrO_2 without NiSO_4 did not exhibit any catalytic activity at all.The catalytic activities were correlated with the acidity of catalysts measured by the ammonia chemisorption method.The addition of FeO up to 5 mol % enhanced the acidity,surface area,thermal property,and catalytic activities of catalysts gradually,due to the interaction between FeO and ZrO_2 and due to consequent formation of Fe-O-Zr bond.