Details
| Original language | English |
|---|---|
| Pages (from-to) | 75-82 |
| Number of pages | 8 |
| Journal | Zeitschrift fur Anorganische und Allgemeine Chemie |
| Volume | 637 |
| Issue number | 1 |
| Early online date | 8 Sept 2010 |
| Publication status | Published - Jan 2011 |
Abstract
Zeolites of type USY (ultra-stable Y) were obtained by steaming of NH 4NaY modification. Samples were modified by subsequent alkaline treatment in KOH solution. USY and USY-KOH were characterised by chemical element analysis, XRD, IR, 29Al and 29Si MAS NMR spectroscopic measurements. Correct silicon to aluminium ratios (Si/Al) were determined by XRD and IR (double ring vibration wDR) data whereas values calculated according to data of 29Si MAS NMR and IR spectroscopy (asymmetrical TOT valence vibration wTOT) appeared to be too high., In the latter case, the signals of the zeolite framework were strongly superimposed by that of extra-framework silica gel (EFSi) formed during steaming. It was found that alkaline leaching induces desilication of silicon-rich area of the zeolite framework and partial dissolution of EFSi. Silicate ions of both react with likewise dissolved extra-framework aluminium (EFAl) to form X-ray amorphous aluminosilicate. Consequently, the superposition of the 29Si MAS NMR signals of the zeolite framework by silica gel was reduced for Q4(0Al) but increased for Q4 (2Al) and Q4(3Al) structure units. A reinsertion of EFAl into the zeolite framework has not been observed.
Keywords
- Aluminum, Alumosilicates, NMR spectroscopy, Silicon, Synthesis design, Zeolites
ASJC Scopus subject areas
- Chemistry(all)
- Inorganic Chemistry
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In: Zeitschrift fur Anorganische und Allgemeine Chemie, Vol. 637, No. 1, 01.2011, p. 75-82.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Reactivity of extra-framework species of USY zeolites in alkaline medium
AU - Lutz, Wolfgang
AU - Bertram, Rainer
AU - Heidemann, Detlef
AU - Kurzhals, Rolf
AU - Rüscher, Claus
AU - Kryukova, Galina
PY - 2011/1
Y1 - 2011/1
N2 - Zeolites of type USY (ultra-stable Y) were obtained by steaming of NH 4NaY modification. Samples were modified by subsequent alkaline treatment in KOH solution. USY and USY-KOH were characterised by chemical element analysis, XRD, IR, 29Al and 29Si MAS NMR spectroscopic measurements. Correct silicon to aluminium ratios (Si/Al) were determined by XRD and IR (double ring vibration wDR) data whereas values calculated according to data of 29Si MAS NMR and IR spectroscopy (asymmetrical TOT valence vibration wTOT) appeared to be too high., In the latter case, the signals of the zeolite framework were strongly superimposed by that of extra-framework silica gel (EFSi) formed during steaming. It was found that alkaline leaching induces desilication of silicon-rich area of the zeolite framework and partial dissolution of EFSi. Silicate ions of both react with likewise dissolved extra-framework aluminium (EFAl) to form X-ray amorphous aluminosilicate. Consequently, the superposition of the 29Si MAS NMR signals of the zeolite framework by silica gel was reduced for Q4(0Al) but increased for Q4 (2Al) and Q4(3Al) structure units. A reinsertion of EFAl into the zeolite framework has not been observed.
AB - Zeolites of type USY (ultra-stable Y) were obtained by steaming of NH 4NaY modification. Samples were modified by subsequent alkaline treatment in KOH solution. USY and USY-KOH were characterised by chemical element analysis, XRD, IR, 29Al and 29Si MAS NMR spectroscopic measurements. Correct silicon to aluminium ratios (Si/Al) were determined by XRD and IR (double ring vibration wDR) data whereas values calculated according to data of 29Si MAS NMR and IR spectroscopy (asymmetrical TOT valence vibration wTOT) appeared to be too high., In the latter case, the signals of the zeolite framework were strongly superimposed by that of extra-framework silica gel (EFSi) formed during steaming. It was found that alkaline leaching induces desilication of silicon-rich area of the zeolite framework and partial dissolution of EFSi. Silicate ions of both react with likewise dissolved extra-framework aluminium (EFAl) to form X-ray amorphous aluminosilicate. Consequently, the superposition of the 29Si MAS NMR signals of the zeolite framework by silica gel was reduced for Q4(0Al) but increased for Q4 (2Al) and Q4(3Al) structure units. A reinsertion of EFAl into the zeolite framework has not been observed.
KW - Aluminum
KW - Alumosilicates
KW - NMR spectroscopy
KW - Silicon
KW - Synthesis design
KW - Zeolites
UR - http://www.scopus.com/inward/record.url?scp=78650716525&partnerID=8YFLogxK
U2 - 10.1002/zaac.201000273
DO - 10.1002/zaac.201000273
M3 - Article
AN - SCOPUS:78650716525
VL - 637
SP - 75
EP - 82
JO - Zeitschrift fur Anorganische und Allgemeine Chemie
JF - Zeitschrift fur Anorganische und Allgemeine Chemie
SN - 0044-2313
IS - 1
ER -