スチレン類二量化に有効な鉄シリカ触媒のXAFS法による構造解析  [in Japanese] XAFS characterization of active Fe species in Fe2O3-SiO2 catalyst for styrene dimerization  [in Japanese]

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Abstract

α-メチルスチレン二量化反応に活性を示す鉄ゾル-ゲル法にて調製した鉄シリカ触媒をX線回折およびX線吸収分光法により評価した.触媒中鉄種の存在状態は仕込みSi /Fe 比に依存し,100 以上では四面体FeOxCl4-x種,50以下ではα-Fe2O3 凝集種が主成分であり,その存在比をXANES解析により求めた.シリカマトリクスに捕捉された孤立FeOxCl4-x が活性種として機能し,固体酸性質を発現する機構について論じた.

Iron ion-promoted silica solid acid catalysts active for α-methylstyrene dimerization were characterized by XRD and Fe K-edge XANES/EXAFS spectroscopic techniques. The possible active species were proposed. The 1 mol % of iron to Si was incorporated in catalyst samples, which was prepared by sol-gel process using iron chloride and tetraethylorthsilicate (TEOS) as the sources. The incorporated trivalent iron species were characterized as tetrahedral FeOxCl4-x , and excess loaded species were aggregated to form α-Fe2O3 during drying process at 403 K. The fraction of [FeOxCl4-x], [FeCl6] and [FeO6] species in the catalyst samples were determined by the least-squares analysis of XANES.

Journal

  • Advances in X-ray chemical analysis

    Advances in X-ray chemical analysis (42), 237-248, 2011-03

    日本分析化学会

Codes

  • NII Article ID (NAID)
    120006411714
  • NII NACSIS-CAT ID (NCID)
    AN0000592X
  • Text Lang
    JPN
  • Article Type
    journal article
  • ISSN
    09117806
  • NDL Article ID
    11072168
  • NDL Source Classification
    ZP4(科学技術--化学・化学工業--分析化学)
  • NDL Call No.
    Z43-488
  • Data Source
    NDL  IR 
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