Synthesis of silica xerogels with highly distinct morphologies in the presence of imidazolium ionic liquids |
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Authors: | R K Donato M V Migliorini M A Benvegnú M P Stracke M A Gelesky F A Pavan C M L Schrekker E V Benvenutti J Dupont H S Schrekker |
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Institution: | 1.Laboratory of Technological Processes and Catalysis, Institute of Chemistry,Universidade Federal do Rio Grande do Sul,Porto Alegre,Brazil;2.Laboratory of Molecular Catalysis, Institute of Chemistry,Universidade Federal do Rio Grande do Sul,Porto Alegre,Brazil;3.Universidade Federal do Pampa,Bage,Brazil;4.Laboratory of Solid State Chemistry and Surfaces, Institute of Chemistry,Universidade Federal do Rio Grande do Sul,Porto Alegre,Brazil |
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Abstract: | This article describes the preparation of silica xerogels by the sol–gel technique, using tetraethoxysilane as precursor and
hydrofluoric acid as catalyst, in the presence of imidazolium ionic liquids (ILs). The applied ILs 1–3 contained the 1-monoethylene glycol monomethyl ether-3-methylimidazolium cation in combination with the methanesulfonate
(1), tetrafluoroborate (2) and hexafluorophosphate (3) anions, respectively. Characterization of these materials was performed by photography, scanning electron microscopy, atomic
force microscopy, X-ray diffraction, thermogravimetric analysis and nitrogen adsorption-desorption isotherms. The IL anion
was identified as a powerful morphology controller. The methanesulfonate anion of IL 1 induced the formation of a compact lamellar monolith with an interlamellar distance of 1.5 nm and a flat surface. A free
flowing powder of aggregated spherical particles was obtained in the presence of tetrafluoroborate IL 2, and the hexafluorophosphate anion of IL 3 induced the formation of porcelain like aggregates with honeycomb shapes.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. |
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Keywords: | Imidazolium ionic liquid Silica xerogel Morphology Sol– gel Anion |
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