Organic–Inorganic Hybrid Saponites Obtained by Intercalation of Titano‐Silsesquioxane

Titanium-silica catalysts, obtained by grafting titanocene dichloride onto mesoporous silica (MCM-41 and MCM-48) and onto nanosized pyrogenic silica, were tested in the epoxidation of methyl oleate using aqueous hydrogen peroxide. All titanium-containing materials, combined with the slow addition of hydrogen peroxide, showed good catalytic activity and comparable behaviour in terms of conversion, selectivity and yield of methyl epoxystearate, notwithstanding the morphology and the texture of the silica support. By optimizing the reaction conditions (especially, the catalyst to substrate ratio), high yields up to 91% in epoxide were obtained for Ti/MCM-41 with a high stereoselectivity (80%) for the cis-epoxide. The formation of the cis/trans-epoxide and the nature of the catalytic reaction pathway are also discussed.

show abstract

“…36 In terms of selectivity, methyl epoxystearate (EPOX), the epoxidised derivative, is the major product (ca. 80%).…”

Section: Resultsmentioning

confidence: 99%

Epoxidation of methyl oleate with hydrogen peroxide. The use of Ti-containing silica solids as efficient heterogeneous catalysts

et al. 2011

Self Cite

View full text Add to dashboard Cite

show abstract

“…Beside fully inorganic clays, in the last years large efforts have been devoted to the preparation of organic-inorganic hybrid materials, aiming to combine the advantages of organic functionalities and inorganic frameworks in solids for catalysis, drug delivery etc. 133,134 Organo-clays are generally prepared by post-synthesis ion-exchange intercalation of surfactant molecules. 135 However, other strategies have been recently explored to modify the surface of clay materials.…”

Section: D Layered Materialsmentioning

confidence: 99%

Combined solid-state NMR, FT-IR and computational studies on layered and porous materials

et al. 2018

Self Cite

View full text Add to dashboard Cite

Understanding the structure-property relationship of solids is of utmost relevance for efficient chemical processes and technological applications in industries. This contribution reviews the concept of coupling three well-known characterization techniques (solid-state NMR, FT-IR and computational methods) for the study of solid state materials which possess 2D and 3D architectures and discusses the way it will benefit the scientific communities. It highlights the most fundamental and applied aspects of the proactive combined approach strategies to gather information at a molecular level. The integrated approach involving multiple spectroscopic and computational methods allows achieving an in-depth understanding of the surface, interfacial and confined space processes that are beneficial for the establishment of structure-property relationships. The role of ssNMR/FT-IR spectroscopic properties of probe molecules in monitoring the strength and distribution of catalytic active sites and their accessibility at the porous/layered surface is discussed. Both experimental and theoretical aspects will be considered by reporting relevant examples. This review also identifies and discusses the progress, challenges and future prospects in the field of synthesis and applications of layered and porous solids.

show abstract

“…More recently Carniato et al [39] demonstrated the intercalation of a bifunctional protonated titanium-containing aminopropyl isobutyl POSS, within the interlayer space of a synthetic sodium saponite and its use as filler in a polystyrene-based nanocomposite designed to enhance the thermooxidative properties. The same group [40] also intercalated Ti-containing aminopropylisobutyl polyhedral oligomeric silsesquioxane in synthetic saponite and investigated the catalytic activity of this composite in cyclohexene oxidation. Other catalysts based on clay-POSS hybrids include synthetic laponite clay first modified by octaaminopropyl polyhedral oligomeric silsesquioxane and then used to support a nickel alpha-diimine late-transitionmetal catalyst for ethylene polymerization [41]; laponite and montmorillonite functionalized with (3-aminopropyl)triethoxysilane and use both as supports for the vanadyl(IV) acetylacetonate catalysis [42] and POSS intercalated bentonites [30] for metal up take of copper, cadmium and lead.…”

Section: Introductionmentioning

confidence: 99%

Iron-substituted cubic silsesquioxane pillared clays: Synthesis, characterization and acid catalytic activity

Potsi

Ladavos

Petrakis

et al. 2018

Journal of Colloid and Interface Science

View full text Add to dashboard Cite

Novel pillared structures were developed from the intercalation of iron-substituted cubic silsesquioxanes in a sodium and an acid-activated montmorillonite nanoclay and evaluated as acid catalysts. Octameric cubic oligosiloxanes were formed upon controlled hydrolytic polycondensation of the corresponding monomer (a diamino-alkoxysilane) and reacted with iron cations to form complexes that were intercalated within the layered nanoclay matrices. Upon calcination iron oxide nanoparticles are formed which are located on the silica cubes (pillars) and on the surfaces of the clay platelets. Acid activation of the nanoclay was performed in order to increase the number of acid active sites in the pristine clay and thus increase its catalytic activity. A plethora of analytical techniques including X-ray diffraction, thermal analyses, Fourier transform infrared, electron paramagnetic resonance, Raman, Mössbauer and X-ray photoelectron spectroscopies and porosimetry measurements were used in order to follow the synthesis steps and to fully characterize the final catalysts. The resulting pillared clays exhibit a high specific area and show significant acid catalytic activity that was verified using the catalytic dehydration of isopropanol asa probe reaction.

show abstract

Organic–Inorganic Hybrid Saponites Obtained by Intercalation of Titano‐Silsesquioxane

Cited by 9 publications

References 44 publications

Epoxidation of methyl oleate with hydrogen peroxide. The use of Ti-containing silica solids as efficient heterogeneous catalysts

Epoxidation of methyl oleate with hydrogen peroxide. The use of Ti-containing silica solids as efficient heterogeneous catalysts

Combined solid-state NMR, FT-IR and computational studies on layered and porous materials

Iron-substituted cubic silsesquioxane pillared clays: Synthesis, characterization and acid catalytic activity

Contact Info

Product

Resources

About