129Xe NMR study of 12-tungstophosphoric heteropoly acid supported on silica

Terskikh, V. V.; Мастихин, В. М.; Timofeeva, Maria N.; Okkel, L. G.; Фенелонов, В. Б.

doi:10.1007/bf00814473

Cited by 11 publications

(7 citation statements)

References 17 publications

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“…It is observed especially at higher temperature and for longer reaction time (2 h). Further increasing of reaction time for PW 12 /SiO 2 (20), even to 6 h (not shown), results in little change in conversion of pseudoionone (additional 5%) while, the distribution of main reaction products is not changed. Our observations concerning the activity of PW 12 supported on commercial silica were consistent with those presented by Diez and coworkers for similar catalytic system [14].…”

Section: Heteropolyacid Supported On Commercial and Mesoporous Silicamentioning

confidence: 71%

“…These pores, present in studied materials originally come from SBA-15. Micropores can be also, as was shown in literature, formed after heteropolyacid adsorption on silica [20]. However, as is presented in Table 1 volume of micropores remains practically unchangeable even for highest PW 12 loading …”

Section: Physicochemical Propertiesmentioning

confidence: 85%

“…However selectivity to this compound, as can be calculated from Fig. 7a and b, is lower over PW 12 /SiO 2 (20) in comparison to PW 12 /SBA-15 (20) (&48% instead 60%). Simultaneously, the selectivity of b-ionone formation reaches higher value and more secondary products were observed.…”

Section: Heteropolyacid Supported On Commercial and Mesoporous Silicamentioning

confidence: 89%

“…Simultaneously, the selectivity of b-ionone formation reaches higher value and more secondary products were observed. It is an evidence that PW 12 /SiO 2 (20) possesses little higher acidity than PW 12 /SBA-15 (20) which slightly favours formation of b isomer and other minor reaction compounds.…”

Section: Heteropolyacid Supported On Commercial and Mesoporous Silicamentioning

confidence: 99%

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Cyclization of Pseudoionone into α-Ionone Over Heteropolyacid Supported on Mesoporous Silica SBA-15

2011

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Cyclization of pseudoionone into a-ionone was performed over the series heteropolyacid supported on SBA-15 in liquid-phase at 363 and 373 K using a batch reactor. It has been demonstrated that the liquid-phase synthesis of a-ionone by pseudoionone cyclization can be efficiently achieved on heteropolyacid/SBA-15 materials. The high catalytic performance of PW 12 /SBA-15 materials is due to their strong Brønsted acidity, high dispersion of active phase and also to absence of steric constraints for pseudoionone cyclization. PW 12 /SBA-15 catalysts are specially active and selective for this reaction giving predominantly a-ionone, as the main product, with high yield (about 60% at 373 K after 2 h) close to that obtained via the homogeneous synthesis. This catalytic system is more active and efficient in comparison with heteropolyacid supported on commercial silica. In order to achieve comparable amount of a-ionone, as is got for PW 12 /SBA-15, belongs to apply five times more of the catalyst based on classical SiO 2 .

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Section: Heteropolyacid Supported On Commercial and Mesoporous Silicamentioning

confidence: 71%

Section: Physicochemical Propertiesmentioning

confidence: 85%

Section: Heteropolyacid Supported On Commercial and Mesoporous Silicamentioning

confidence: 89%

Section: Heteropolyacid Supported On Commercial and Mesoporous Silicamentioning

confidence: 99%

See 2 more Smart Citations

Cyclization of Pseudoionone into α-Ionone Over Heteropolyacid Supported on Mesoporous Silica SBA-15

2011

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“…In comparison with the lattice parameter of the salts (1.1-1.3 nm), their results agree better than those obtained by the classical porosimetry method (1.9-2.9 nm). Later Terskikh et al 86 showed that 12-tungstophosphoric heteropolyacids (HPA) supported on silica can be adsorbed as isolated molecules at low coverage but at high coverage form large clusters (50 nm) in which xenon can be adsorbed. It is then possible to follow the clustering of HPA molecules 'step by step'.…”

Section: Investigation By 129 Xe Nmr Of Microporous Solids Other Thanmentioning

confidence: 99%