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

Abstract

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.

Tin-containing silicates: structure–activity relations

“…• C for 15 h. SBA-15 (Ramaswamy et al 2008) was prepared by dissolving 8.0 g of Pluronic P-123 (PEG-PPG-PEG polymer, Mw = 5800 g mol −1 ) in 60.0 g of water. A solution of 1.0 g of HCl (37 wt.%) in 140 g of water was added, and the mixture stirred for 2 h. Then, 18.0 g of TEOS and the desired amount of SnCl 4 · 5H 2 O dissolved in 2.0 g of water was added slowly.…”

Confinement Effects in Lewis Acid-Catalyzed Sugar Conversion: Steering Toward Functional Polyester Building Blocks

“…Sn-SBA-15 was prepared according to a procedure described by Ramaswamy et al 6 For this, 4.0 g of Pluronic P-123 (PEG,PPG,PEG polymer, MW = 5800 g mol -1 , Sigma Aldrich) was dissolved in 30.0 g of water. Then, 0.5 g of a 37 wt% HCl solution, diluted with 70 g of water, was added and the mixture was stirred for 2 h. Afterwards, 9.0 g of TEOS and 0.302 g of SnCl 4 .5H 2 O dissolved in 1.0 g of water were added dropwise and the mixture was stirred for another 24 h at 313 K to obtain a gel with an approximate composition of 1 SiO 2 :0.02SnO 2 :0.016P123:0.14Cl -:134H 2 O.…”

Shape‐selective Valorization of Biomass‐derived Glycolaldehyde using Tin‐containing Zeolites

“…Sn‐SBA‐15 (Si/Sn=200) was prepared following the synthesis route described by Ramaswamy et al . Initially, 8.0 g of Pluronic P‐123 (PEG‐PPG‐PEG polymer, M w =5800 g mol −1 ) was dissolved in 60 g of demineralized water, followed by the addition of 1.0 g of hydrochloric acid (HCl, 37 wt %) in 140 g of demineralized water.…”