NMR Characterization of Mesostructured Aluminophosphates

Schulz, M.; Tiemann, Michael; Fröba, Michael; Jäger, Christian

doi:10.1021/jp000337n

Cited by 27 publications

(31 citation statements)

References 47 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the latter case, the alkyl chain is decomposed at a higher temperature (200°C) and the sulfate group at a lower temperature (250°C) indicating a strong interaction between the sulfate head group and the alumina framework when the DS is occluded. This conclusion is similar to that obtained for lamellar aluminophosphates synthesized in the presence of mono-ndodecyl phosphate [33][34][35]. Indeed, it was clearly showed that the phosphate head group of the surfactant was embedded within the alumina framework, leading to the formation of an aluminophosphate.…”

Section: Study Of the Mechanism Of Formation Of A Mesostructured Aluminasupporting

confidence: 89%

Synthesis of Mesostructured Or Mesoporous Aluminas in the Presence of Surfactants. Comprehension of the Mechanisms of Formation

Sicard

Lebeau

Patarin

et al. 2003

Oil & Gas Science and Technology - Rev. IFP

View full text Add to dashboard Cite

-Synthèse d'alumines mésostructurées et mésoporeuses en présence de tensioactifs. Compréhension des mécanismes de formation-Ce travail présentait un double objectif : la synthèse d'alumines mésoporeuses en milieu aqueux et la compréhension des mécanismes de formation. Des alumines mésoporeuses ont été obtenues à partir d'une solution acide de polycation de Keggin d'aluminium et d'une micelle mixte de palmitate de sodium et de bromure de cétyltriméthylammonium. Le diamètre des pores a pu être augmenté en élevant le pH final. La synthèse d'alumines a également été réalisée à partir d'une solution basique d'aluminate de sodium. Des volumes poreux et des surfaces spécifiques très importants ont été obtenus par lavage du précipité à l'éthanol ou à l'acétone et non à l'eau. Une étude fondamentale de compréhension du mécanisme de formation d'une alumine mésostructurée, de symétrie hexagonale, a également été menée pour améliorer les modes opératoires. L'étude des interactions entre tensioactif et charpente aluminique nous a permis d'expliquer pourquoi la structure s'effondre lors de la calcination. Un mécanisme de formation, basé sur des observations de fluorescence, est également présenté. Il a été établi que les espèces aluminiques interagissent avec les micelles et polymérisent à leur surface. Cependant, les micelles sont quasi sphériques tout au long de l'expérience et ne se réorganisent pas selon une symétrie hexagonale avant l'apparition d'un précipité.

show abstract

Section: Study Of the Mechanism Of Formation Of A Mesostructured Aluminasupporting

confidence: 89%

Synthesis of Mesostructured Or Mesoporous Aluminas in the Presence of Surfactants. Comprehension of the Mechanisms of Formation

Sicard

Lebeau

Patarin

et al. 2003

Oil & Gas Science and Technology - Rev. IFP

View full text Add to dashboard Cite

show abstract

“…3), suggests that the majority of the Al species are tetrahedral coordination Al(OP) 4 groups [23,24]. The 31 P MAS NMR spectra of the two calcined samples exhibit a strong signal centered at À 24 ppm, which can be mainly attributed to 4-fold coordinated P with O -Al [23,24]. The relatively broad resonance may be partly caused by the presence of a small amount of P species coordinating with H 2 O or OH groups, and may also imply the amorphous characteristic of the pore wall.…”

Section: Resultsmentioning

confidence: 99%

Thermally stable mesoporous aluminophosphates assembled from preformed precursors of microporous aluminophosphate

Zhou¹,

Liu²,

Zhang³

et al. 2005

Materials Letters

View full text Add to dashboard Cite

“…31 P magic-angle spinning (MAS) NMR has been used to probe the local environment around P, and for a number of these mesostructured AlPO materials, their 31 P MAS spectra usually exhibit multiple peaks, indicating the existence of different P local structures. 3a,c,f,4c,d, 5,10 The spectral assignments usually begin with a comparison of the observed 31 P chemical shifts with those reported for AlPO 4 -based three-dimensional microporous materials whose 31 P chemical shift values often fall in the range of -19 to -30 ppm. 3a,11 As previously mentioned, in those AlPO 4 -based materials, the P sites only have one type of P chemical environment, P(-OAl) 4 .…”

Section: Introductionmentioning

confidence: 99%

Characterization of BAPO- and SAPO-Based Mesoporous Materials by Solid-State NMR Spectroscopy

2005

View full text Add to dashboard Cite

We have utilized several heteronuclear dipolar-coupling based 27 Al/ 31 P, 31 P/ 11 B, 27 Al/ 11 B, 27 Al/ 29 Si, and 1 H/ 31 P double-resonance solid-state NMR techniques to characterize boroaluminophosphate (BAPO)-and silicoaluminophosphate (SAPO)-based mesoporous materials. For the hexagonal BAPO materials, the coordination geometry of the B atoms in the framework is exclusively tetrahedral. The fraction of B atoms that can be incorporated in the framework seems not to depend on the B content of the initial gel. For the vast majority of the framework B atoms, the coordination environment is B(-OP) 4 . The B-OAl linkages, however, also exist. The results indicate that the four-coordinated B atoms are not distributed randomly within the framework. Instead, they appear to be located on the channel surface. For the SAPObased mesophase, the connectivities between various P and Al sites were mapped and the chemical environments of different P sites were determined to be as follows: (HO) 2 P[OAl(oct)] 2 , (HO)P[OAl(tet)] x -[OAl(oct)] 3-x , and (HO)P[OAl(tet)] 3 . The Si-O-Al linkages were detected unambiguously.

show abstract

NMR Characterization of Mesostructured Aluminophosphates

Cited by 27 publications

References 47 publications

Synthesis of Mesostructured Or Mesoporous Aluminas in the Presence of Surfactants. Comprehension of the Mechanisms of Formation

Synthesis of Mesostructured Or Mesoporous Aluminas in the Presence of Surfactants. Comprehension of the Mechanisms of Formation

Thermally stable mesoporous aluminophosphates assembled from preformed precursors of microporous aluminophosphate

Characterization of BAPO- and SAPO-Based Mesoporous Materials by Solid-State NMR Spectroscopy

Contact Info

Product

Resources

About