Synthesis and characterization of tin oxide-modified mesoporous SBA-15 molecular sieves and catalytic activity in trans-esterification reaction

Shah, Pallavi; Ramaswamy, A.V.; Lázár, K.; Ramaswamy, V.

doi:10.1016/j.apcata.2004.06.039

Cited by 94 publications

(40 citation statements)

References 46 publications

(48 reference statements)

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“…8a, b and c, respectively. They exhibit very similar patterns with wellresolved diffraction peaks at 0.8°(2h) and 2 weak peaks at 1.6 and 1.7°(2h) due to (10), (11) and (20) Bragg reflections, respectively. The characteristic hexagonal features of the parent SBA-15 are maintained in all the Sn-SBA-15 samples.…”

Section: Structure Of Sn-sba-15 Samplesmentioning

confidence: 71%

“…Progressively, from conditions C to E (pH \ 1 to \2) the percent contribution of microporosity to the total pore volume increases. Under normal conditions of preparation of SBA-15 (very low pH), the micropore volume is reported to be about 5-8% of the overall pore volume [11,12]. In our present samples, the contribution of microporosity to the total pore structure increases from 10 to 16%.…”

Section: Porosity and Surface Areamentioning

confidence: 79%

“…On calcination they are removed, leaving open micropores [67]. Imperor-Clerc et al [64] have noted an increase in the intensity of the reflections (10), (11) and (20), on annealing these micropores by hydrothermal treatment, which increases the pore diameter slightly. Incorporation of Sn induces an increase in the intensity due to the X-ray scattering of the large (*6 nm) particles at the outer surface of the SBA-15 pores.…”

Section: Structure Of Sn-sba-15 Samplesmentioning

confidence: 96%

“…This is fairly a good indication of the presence of Sn in the corona region of the mesopore structure. In our earlier report, we found that when SBA-15 was impregnated with Sn ions using SnCl 4 solution, there was a decrease in total surface area and pore volume due to some blockage of the mesopores [11,12].…”

Section: Porosity and Surface Areamentioning

confidence: 98%

“…There are many reports on the synthesis and characterization of mesoporous silicas with Sn-and other semiconducting oxides in them, prepared either by direct synthesis or by post-synthesis procedures [6][7][8][9][10][11][12]. Highly acidic conditions of preparation of Si-SBA-15 normally prohibit the incorporation of Al, Sn, etc., from the synthesis gel due to the high solubility of their precursors.…”

Section: Introductionmentioning

confidence: 99%

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Synthesis, Characterization and Catalytic Activity of Sn-SBA-15 Mesoporous Molecular Sieves

Ramaswamy

Shah

Lázár³

et al. 2008

Catal Surv Asia

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Our recent reports on the synthesis of Sn-incorporated mesoporous SBA-15 materials have been reviewed. The preparation of the samples with different Si/Sn ratios followed two procedures, the first is the post-synthesis modification of SBA-15 by impregnation with Sn chloride or acetate, and the second is the direct method in which Sn chloride was introduced in to Si precursor along with amphiphilic triblock copolymer, while varying the n H 2 O =n HCl ratio of the synthesis gel. Detailed characterization of the Sn-SBA-15 samples by a variety of techniques shows how the synthesis procedures influence the properties of the samples that reflect on the differences in (a) the structural features, (b) morphology and textural properties, such as the pore characteristics, (c) the possible location of Sn 4? ions in the meso silica structure and their reducibility, (d) the nature of the Sn species and their the coordination sphere and (e) the acid-base characteristics. We developed a possible model for the localization of Sn species in SBA-15 pore structure for different conditions of preparation. This report includes our investigations on the catalytic properties of these Sn-SBA-15 samples in 3 industrially important reactions, viz., trans-esterification of diethyl malonate, synthesis of nopol by Prins condensation of b-pinene with para-formaldehyde and the epoxidation of norbornene. In each of this reaction, while demonstrating the catalytic role of Sn species, we show that the requirement of the type and the environment of Sn species are different for these reactions.

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Section: Structure Of Sn-sba-15 Samplesmentioning

confidence: 71%

Section: Porosity and Surface Areamentioning

confidence: 79%