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Microporous PILCs : Synthesis, pillaring mechanism and selective cation exchange

Titelangaben

Stöcker, Melanie ; Seyfarth, Lena ; Hirsemann, Dunja ; Senker, Jürgen ; Breu, Josef:
Microporous PILCs : Synthesis, pillaring mechanism and selective cation exchange.
In: Applied Clay Science. Bd. 48 (März 2010) Heft 1-2 . - S. 146-153.
ISSN 0169-1317
DOI: https://doi.org/10.1016/j.clay.2009.11.013

Abstract

Based on a 3-dimensionally ordered, synthetic Cs-hectorite (Cs0.56[Mg2.44Li0.56]<Si4> O10F2) a truly microporous pillared inter-layered clay (PILC) was obtained by intercalation of diprotonated DABCO molecules (DABCO = 1,4-diazabicyclo[2.2.2]-octane). Not only is the stacking order retained upon pillaring (C 2/m (no. 12); a = 5.247(1) Å, b = 9.083(2) Å, c = 14.581(5) Å and β = 96.799°), additionally, a 2-dimensional long range order of the pillars in the interlamellar space was observed. Indexing proved this 2-dimensional superstructure to be commensurable with the host (a⁎ ≈ 3 × a = 15.731(3) Å, b⁎ ≈ b = 9.090(2) Å). This in turn suggests that it is not the electrostatic repulsion between the positively charged pillars but instead the host–guest-fit that determines the lateral arrangement of pillars in the interlamellar space.

The large crystal sizes, which this PILC comes with, allowed to verify that intercalation of the organic pillars follows the ring mechanism in accordance with what has been proposed some years ago by Weiss et al. (1970).

Noteworthy, upon intercalation, the acidic protons undergo a fast dynamic exchange between the pillars, water molecules present in the micropores, and framework atoms of the host. Consequently, a considerable amount of the open space between the pillars is actually occupied by H3O+ and H2O, which cannot be removed completely by drying. Interestingly, a selective partial cation exchange of these acidic protons by Na+ could be achieved.

Thus, pillaring with 2H-DABCO affords a well ordered, Brønsted-acidic, microporous material with a narrow pore size distribution.

Weitere Angaben

Publikationsform: Artikel in einer Zeitschrift
Begutachteter Beitrag: Ja
Keywords: Clay; Hectorite; Intercalation mechanism; Microporous hybrid material; PILC; Porosity
Institutionen der Universität: Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften
Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften > Fachgruppe Chemie
Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften > Fachgruppe Chemie > Lehrstuhl Anorganische Chemie I > Lehrstuhl Anorganische Chemie I - Univ.-Prof. Dr. Josef Breu
Forschungseinrichtungen > Sonderforschungsbereiche, Forschergruppen > SFB 840 Von partikulären Nanosystemen zur Mesotechnologie
Forschungseinrichtungen > Sonderforschungsbereiche, Forschergruppen > SFB 840 Von partikulären Nanosystemen zur Mesotechnologie > SFB 840 - TP A 6
Fakultäten
Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften > Fachgruppe Chemie > Lehrstuhl Anorganische Chemie I
Forschungseinrichtungen
Forschungseinrichtungen > Sonderforschungsbereiche, Forschergruppen
Titel an der UBT entstanden: Ja
Themengebiete aus DDC: 500 Naturwissenschaften und Mathematik > 500 Naturwissenschaften
500 Naturwissenschaften und Mathematik > 540 Chemie
Eingestellt am: 23 Mär 2018 07:56
Letzte Änderung: 23 Mär 2018 07:56
URI: https://eref.uni-bayreuth.de/id/eprint/9953