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Al ratios and different aluminum sources
202
06-P-17 - 27Al-NMR studies on A I - M C M - 4 1 molecular sieves synthesized with different Si/A! ratios and different a l u m i n u m sources W. BOhlmann and D. Michel
University of Leipzig, Faculty of Physics and Geosciences, LinnOstr. 5, D-04103 Leipzig, Germany, e-mail. bohlmann@physik uni-leipzig, de AI-MCM-41 molecular sieves in there sodium and hydrogen form with different Si/A1 ratios (16...256) were synthesized using aluminum sulfate and aluminum triisopropylate as source. In all experiments the pH value was held at about 10 during the synthesis procedure. The products in the as-synthesized form and after calcination were characterized by means of XRD diffraction, nitrogen adsorption-desorption, and two different techniques of the solidstate 27A1 MAS NMR spectroscopy. Applying the cross-polarization (CP) magic angle spinning (MAS) spectroscopy makes it possible to determine the local environments of the aluminum species and to distinguish better between framework and non-framework aluminum.
06-P-18 - Control of formation of m e s o p o r o u s SBA-3 and SBA-1 through organic additives S. Che and T. Tatsumi
Division of Materials & chemical Engineering, Faculty of Engineering, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501, Japan The synthesis and kinetics of formation of SBA-1 mesoporous molecular sieve was greatly affected by the addition of trimethylbenzene (TMB) isomers. The synthesis of SBA-1 was performed at 0~ using tetraethyl orthosilicate (TEOS) as the silicon source and cetyltriethylammonium bromide (CTEABr) as the template under acidic conditions. XRD shows that a well ordered hexagonal p6mm SBA-3 mesophase rapidly forms and then transforms to cubic Pm3n SBA-1 mesophase with proper TMB/CTEABr molar ratios. The presence of 1,2,3-TMB was the most favored to form p6mm hexagonal mesophase, and 1,2,4TMB showed an intermediate behavior.
06-P-19 - The influence of AI, La or Ce in the thermal and h y d r o t h e r m a l properties of M C M - 4 1 m e s o p o r o u s solids R.A.A. Melo and E.A. Urquieta-Gonzfilez*
Dep. Chem. Eng., C. Postal 676, S~o Carlos-SP, Brazil. e-mail." [email protected] The thermal (at 1153 K) and hydrothermal stability (at 933 K) of Si-, AI-, La- and Ce-MCM41 were studied. The solids were synthesized at 373 K. XRD data indicated that Si-MCM-41 presented the more resolved XRD pattern, therefore the most ordered porous structure. XRD and N2 sorption showed that the thermal treatment leads to a structure degradation with LaMCM41 showing the higher stability and Ce-MCM-41 suffering a total structure collapse. In the hydrothermal treatment, Ce-MCM-41 maintained above of 80% of its SBETarea and 55% of its primary mesoporous volume. In those thermally conditions La-MCM-41and A1-MCM41 were more stable than Si-MCM-41. The intensity of the band at 960 cm l in the FT-IR spectra can be well related with the order of porous array in the prepared MCM-41 solids.
06-P-17 - 27Al-NMR studies on A I - M C M - 4 1 molecular sieves synthesized with different Si/A! ratios and different a l u m i n u m sources W. BOhlmann and D. Michel
University of Leipzig, Faculty of Physics and Geosciences, LinnOstr. 5, D-04103 Leipzig, Germany, e-mail. bohlmann@physik uni-leipzig, de AI-MCM-41 molecular sieves in there sodium and hydrogen form with different Si/A1 ratios (16...256) were synthesized using aluminum sulfate and aluminum triisopropylate as source. In all experiments the pH value was held at about 10 during the synthesis procedure. The products in the as-synthesized form and after calcination were characterized by means of XRD diffraction, nitrogen adsorption-desorption, and two different techniques of the solidstate 27A1 MAS NMR spectroscopy. Applying the cross-polarization (CP) magic angle spinning (MAS) spectroscopy makes it possible to determine the local environments of the aluminum species and to distinguish better between framework and non-framework aluminum.
06-P-18 - Control of formation of m e s o p o r o u s SBA-3 and SBA-1 through organic additives S. Che and T. Tatsumi
Division of Materials & chemical Engineering, Faculty of Engineering, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501, Japan The synthesis and kinetics of formation of SBA-1 mesoporous molecular sieve was greatly affected by the addition of trimethylbenzene (TMB) isomers. The synthesis of SBA-1 was performed at 0~ using tetraethyl orthosilicate (TEOS) as the silicon source and cetyltriethylammonium bromide (CTEABr) as the template under acidic conditions. XRD shows that a well ordered hexagonal p6mm SBA-3 mesophase rapidly forms and then transforms to cubic Pm3n SBA-1 mesophase with proper TMB/CTEABr molar ratios. The presence of 1,2,3-TMB was the most favored to form p6mm hexagonal mesophase, and 1,2,4TMB showed an intermediate behavior.
06-P-19 - The influence of AI, La or Ce in the thermal and h y d r o t h e r m a l properties of M C M - 4 1 m e s o p o r o u s solids R.A.A. Melo and E.A. Urquieta-Gonzfilez*
Dep. Chem. Eng., C. Postal 676, S~o Carlos-SP, Brazil. e-mail." [email protected] The thermal (at 1153 K) and hydrothermal stability (at 933 K) of Si-, AI-, La- and Ce-MCM41 were studied. The solids were synthesized at 373 K. XRD data indicated that Si-MCM-41 presented the more resolved XRD pattern, therefore the most ordered porous structure. XRD and N2 sorption showed that the thermal treatment leads to a structure degradation with LaMCM41 showing the higher stability and Ce-MCM-41 suffering a total structure collapse. In the hydrothermal treatment, Ce-MCM-41 maintained above of 80% of its SBETarea and 55% of its primary mesoporous volume. In those thermally conditions La-MCM-41and A1-MCM41 were more stable than Si-MCM-41. The intensity of the band at 960 cm l in the FT-IR spectra can be well related with the order of porous array in the prepared MCM-41 solids.