酸素欠陥のある固体Keggin型フォスフォムリブド酸に対する酸化触媒
Satoshi Ishikawa1, Takuji Ikeda2, Maki Koutani1
1Department of Material and Life Chemistry, Faculty of Engineering, Kanagawa University, 3-27-1, Rokkakubashi, Kanagawa-ku, Yokohama 221-8686, Japan.
Journal of the American Chemical Society
|April 19, 2022
まとめ
ピリジンで処理されたフォスフォモリブド酸 (PyPMo-HT) は,選択的酸化のための強化された触媒活性を示します. これは,電子移転によって形成された電気的酸素種から生じ,産業用ポリオキシメタレート触媒におけるメタクリル酸の産出量を改善します.
科学分野:
- 異質な触媒
- 材料科学
- 無機化学
背景:
- ケギン型フォスフォモリブド酸 (PMo12O40) 誘導体は,ガス相酸化触媒において有望である.
- PyPMo-HTのような改造されたポリオキシメタレート (POM) の触媒作用の正確な起源については,詳細な調査が必要である.
- 構造と活動の関係を理解することは,POMベースの産業用触媒の最適化に不可欠です.
研究 の 目的:
- 熱処理後のピリジン処理されたリン酸 (PyPMo-HT) の結晶構造を明らかにする.
- 観察された酸化活動に起因する触媒的に活性な種を特定する.
- 選択的酸化反応において,構造的変異と触媒性能の強化を相関させる.
主な方法:
- 不活性ガス流下でピリジンでフォスフォモリブド酸の熱処理によるPyPMo-HTの合成
- PyPMo-HTの結晶構造の決定
- プロピレンとメタクロレインの分子酸素と触媒酸化を含む反応機構の調査.
主要な成果:
- PyPMo-HTは,特定のHPy/Keggin比を持つKeggin単位とピリジニウムカチオンの一次元配列を形成する.
- 変換中の酸素の除去は,Mo原子の局所電子密度につながり,電子の移転を容易にします.
- 選択的酸化の活性部位として機能し,高いメタクリル酸を生成するブリッジケギン単位を形成した.
結論:
- ピリジン処理によるリン酸の構造変化により,活性な電離性酸素種が生成される.
- PyPMo-HTは,メタクロレイン酸化に対する優れた触媒活性を示しています.
- この研究は,産業用酸化プロセスにおけるポリオキシメタラートベースの触媒の理解を深める.
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