Study of Te and V as counter-cations in Keggin type phosphomolybdic polyoxometalate catalysts for isobutane oxidation

Effect of vanadyl species in Keggin-type heteropoly catalysts in selective oxidation of methacrolein to methacrylic acid

“…The split bands in the region 230-250 cm À1 were due to the deformation vibrations of the terminal M@O groups and the entire framework [23]. The band at 625 cm À1 was assigned to MoAO c AMo vibration bands [24], while the bands in the region 876-909 cm À1 region were assigned to MoAO b AMo and MoAOAP stretching vibrations, respectively, which only exist in the integral Keggin structure [25]. The bands at 984 (shoulder) and 1002 cm À1 were assigned to MoAO d stretching bands [26].…”

Control of the modularity of {Mo2O2S2}-containing polyoxometalates. Synthesis, structure and characterization of tri- and tetra-modular assemblies based on the [β-B-AsW9O33]9− anion

“…Polyoxometalate compounds (POMs) constitute potentially attractive chemical systems able to generate large assemblies with targeted functionalities [1][2][3][4][5] and promising applications in diverse fields of science, such as catalysis [6][7][8][9], medicine [10][11][12][13][14], electrochemistry [15] and material sciences [16][17][18][19][20][21]. To this end, this class of compounds offers the possibility to use polyvacant anions as primary building blocks to step by step construct sophisticated well-designed multi-unit compounds.…”

Forty years of temporal analysis of products

“…For example, when investigating the partial oxidation of isobutane to methacrylic acid over Keggin-type phosphomolybdic polyoxometalate catalysts, product pulse responses were always observed in the order "isobutene, methacrolein, CO 2 then methacrylic acid". 98 The observation of isobutene in this TAP experiment is significant because conventional reactor testing did not indicate its formation (isobutene is oxidized much faster than isobutane); thus it was often left out of the reaction mechanism. The TAP experiment by Schuurman and co-workers, however, clearly indicated that isobutene was formed first and should thus be considered as an intermediate.…”