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

Zhou, Lilong; Wang, Lei; Zhang, Suojiang; Yan, Ruiyi; Diao, Yanyan

doi:10.1016/j.jcat.2015.05.031

Cited by 77 publications

(57 citation statements)

References 37 publications

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“…According to the TG-DSC analysis, Cs 2 Cu x and Cs 2 Fe x catalysts completely decomposed when temperature was above 430°C. Hence, the reduction peaks between 450 and 600°C can be assigned to the reduction of the MoO 3 formed from the decomposition of the Keggin anions during the H 2 -TPR experiment [19]. As shown in Figure 7a, with increasing Cu content, the main peak shifted from 582°C to 493°C suggesting that the replacement of protons by Cu would enhance the oxidizing ability of catalysts.…”

Section: Nh 3 -Tpd Analysismentioning

confidence: 91%

“…As shown in Figures 2a and 2c, before calcination, the catalysts exhibited main bands that attributed to Keggin structure. The split bands in the region 220-270 cm -1 were caused by the deformation vibrations of the terminal M=O groups and the entire framework [18,19] [20,21]. After calcination, the main bands of Keggin structure were still reserved (Figures 2b and 2d).…”

Section: Raman Analysismentioning

confidence: 97%

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Cu or Fe Modified Cs2HPMo12O40 as Catalysts for Selective Oxidation of Methacrolein

Wang¹,

Liu²

2016

J Thermodyn Catal

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Section: Nh 3 -Tpd Analysismentioning

confidence: 91%

Section: Raman Analysismentioning

confidence: 97%

Cu or Fe Modified Cs2HPMo12O40 as Catalysts for Selective Oxidation of Methacrolein

Wang¹,

Liu²

2016

J Thermodyn Catal

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“…It has been reported that V can partially substitute for Mo in the heteropolyanions and improve the catalytic property for selective oxidation reactions [12,13]. In particular, effective catalysts can be designed and prepared by controlling the distribution of vanadyl species in the primary or secondary structure [14]. Compared with the parent heteropolyacids, the formation of acidic salts with alkaline metals is effective on both the activity and stability of in water or other polar solvents, precipitate is generated in the heteropolyacids solution after the addition of these ions, and then the obtained slurry is usually evaporated to dryness to get the acidic cesium or ammonium salts.…”

Section: Introductionmentioning

confidence: 99%

Composition, Structural Evolution and the Related Property Variations in Preparation of Mixed Cesium/Ammonium Acidic Salts of Heteropolyacids

Zhang

Wang

et al. 2016

Catalysts

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Abstract:The composition, structural evolution and the related property variations of mixed cesium/ammonium acidic salts of heteropolyacids were investigated in detail by tracking and analyzing the initial precipitates, evaporation residues and the calcined products in their preparation process. Results show that V cannot completely enter the heteropolyanions in the initial precipitates when the Cs + added amount is low, and the increase in Cs + adding amount improves the substitution of V for Mo in the heteropolyanions. Both the initial precipitates and the evaporation residues are mixtures of cesium and ammonium salts of heteropolyacids before calcination. Thermal treatment causes the decomposition of the ammonium salts and the formation of single-phase solid solutions from mechanical mixtures. The calcined products of the initial precipitates and the evaporation residues vary greatly in textural properties. The determinants of the catalytic performance for the oxidation of methacrolein to methacrylic acid are acidity and specific surface area of the compounds. The increase in specific surface area mainly improves the conversion of methacrolein, but not the selectivity of methacrylic acid. Insufficient acidity caused by high Cs + content in the compounds is responsible for the low selectivity.

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“…Among different HPAs, Keggin type (such as phosphotungstic acid) are well known and widely studied compounds for various catalytic applications, such as Friedel-Craft's alky-lation, acylation, oxidation, hydration of alkenes, esterification, transesterification, and carbonylation [9][10][11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Characterization and Catalytic Polymerization of N-Methyl Imidazolium Phosphotungstic Catalyst

et al. 2015

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N-methyl imidazolium phosphotungstic salt has been synthesized and used as a special catalyst for photopolymerization of vinyl monomers. This is a fast and smooth reaction, and high molecular weight polymers with narrow polydispersity are obtained within 60 min. The compound was structurally characterized by elemental analysis, IR spectroscopy, and 1 H NMR spectroscopy. The electrochemical property is determined on a CHI 660 electrochemistry workstation. The polymerization initiated by N-methyl imidazolium phosphotungstic salt showed controlling characteristics, the catalyst can be easily isolated from polymer product, and reused for at least 10 times.

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

Cited by 77 publications

References 37 publications

Cu or Fe Modified Cs2HPMo12O40 as Catalysts for Selective Oxidation of Methacrolein

Cu or Fe Modified Cs2HPMo12O40 as Catalysts for Selective Oxidation of Methacrolein

Composition, Structural Evolution and the Related Property Variations in Preparation of Mixed Cesium/Ammonium Acidic Salts of Heteropolyacids

Synthesis, Characterization and Catalytic Polymerization of N-Methyl Imidazolium Phosphotungstic Catalyst

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