Keggin-type H4PVMo11O40-based catalysts for the isobutane selective oxidation

Abstract

Cesium heteropolysalts Cs 3 PMo 12 O 40 and HCs 3 PVMo 11 O 40 were synthesized by modifying the preparation conditions in order to get materials with a much higher surface area than the original Keggin-type heteropolyacids (H 3 PMo 12 O 40 and H 4 PVMo 11 O 40 ). These solids were used as carriers for the dispersion of H 4 PVMo 11 O 40 heteropolyacid by the incipient wetness impregnation technique. The textural and structural properties of supports and catalysts were examined by scanning electron microscopy, N 2 adsorption-desorption isotherms and Raman spectroscopy. The supported catalysts were studied before and after red/ox pretreatments by X-ray photoelectron spectroscopy, which showed that both the surface composition and oxidized to reduced species ratio depend on the used carrier. The catalytic performances of these novel supported catalysts in the selective oxidation of isobutane to methacrylic acid and methacrolein were studied. The best catalytic properties were obtained when H 4 PVMo 11 O 40 was supported on HCs 3 PVMo 11 O 40 . The isobutane conversion and yield of the desired oxygenates increased along the unsupported H 4 PVMo 11 O 40 < H 4 PVMo 11 O 40 /Cs 3 PMo 12 O 40 < H 4 PVMo 11 O 40 /HCs 3 PVMo 11 O 40 series. cesium heteropolysalts supports, supported H 4 PVMo 11 O 40 , red/ox XPS, isobutane selective oxidation, Keggin-type heteropolycompounds

Keggin‐type Heteropolyacids‐Catalyzed Selective Hydrothermal Oxidation of Microalgae for Low Nitrogen Biofuel Production

“…The bands at 243 cm −1 are due to the deformation vibrations of terminal Mo=O groups and the entire framework. However, these characteristic bands regarding to the Keggin structure would be gradually migrated to higher bands with the increase of the substitution of vanadium [35] . To further confirm the Keggin structures of the HPAs, their XRD patterns are recorded and presented in Figure 1d.…”

“…However, these characteristic bands regarding to the Keggin structure would be gradually migrated to higher bands with the increase of the substitution of vanadium. [35] To further confirm the Keggin structures of the HPAs, their XRD patterns are recorded and presented in Figure 1d. There are distinct diffraction peaks in the range of 8-10°, 16-23°, 25-30°, and 31-38°exhibited in the XRD patterns of all three samples, which are highly consistent with the characteristic peaks of POMs corresponding to H 3 + n PMo 12-n V n O 40 in the XRD database.…”

Oxidation kinetics of 2‐methyl‐1,3‐propanediol to methacrylic acid in a fluidized bed reactor

“…High yield requires the recycling of unreacted isobutane. [ 22–29 ]…”

“…High yield requires the recycling of unreacted isobutane. [22][23][24][25][26][27][28][29] Partial oxidation of 2-methyl-1,3-propanediol (2MPDO) to MAA and MAC is a new process that was proposed for the first time in 2014, and it partially overcomes the disadvantages of other processes. [15,[30][31][32] 2MPDO is a co-product of 1,4-butanediol in the hydroformylation process of allyl alcohol and has few applications.…”

Structural Evolution under Reaction Conditions of Supported (NH4)3HPMo11VO40 Catalysts for the Selective Oxidation of Isobutane

“…More particularly, vanado-molybdo-phosphoric acid (H4PMo11VO40) is a promising bi-functional catalyst for the direct oxidation of isobutane (IBAN) into methacrylic acid (MAA) because of its acidic and redox chemical properties [7][8][9][10]. However, the thermal stability of this catalyst, which restructures on-stream, is poor [11].…”