Acrolein oxidation over 12-molybdophosphates: III. Reaction mechanism
Acrolein oxidation over 12-molybdophosphates: III. Reaction mechanism
复制标题
丙烯醛在 12-钼磷酸盐上的氧化：III。
DOI：
10.1016/0021-9517(87)90207-7
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发表时间：
1987
期刊：
影响因子：
--
通讯作者：
J. Goodenough
中科院分区：
文献类型：
--
作者：
E. Serwicka;J. Black;J. Goodenough
ESR and IR measurements have identified the mechanism by which acrolein is oxidized to acrylic acid over K3PMo12O40. Under dry conditions at room temperature, acrolein is physisorbed at a bridging oxygen of the Keggin (PMo12O40)3−anion; the bridging oxygen makes a nucleophilic attack on the carbonyl carbon of the acrolein molecule. In air at room temperature, water adsorption competes for the active sites. In the temperature interval 293 K <T< 453 K, the acrolein molecule becomes increasingly dissociatively chemisorbed to form an acrylate-type species, two electrons and a proton being transferred to the Keggin unit. Electron and proton transfer occurs between Keggin units, and the electron redistribution produces an ESR signal symmetric at 77 K that is typical for a Keggin unit reduced by one electron. Above 453 K, recapture of a proton by the acrylate anion produces acrylic acid desorption, which leaves the Keggin unit reduced and containing an oxygen vacancy at which a trapped electron gives an asymmetric Mo(V) signal.
