Covalent grafting of phenylphosphonate groups onto layered silica derived from in situ-leached chrysotile fibers

Schreiner, W. H.; Mattoso, N.; Mosca, D. H.; Marangoni, Rafael; Bento, Carlos A. da S.

doi:10.1039/b210370b

Cited by 40 publications

(48 citation statements)

References 30 publications

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“…As would be expected for surface grafting and immobilization, all the samples present the X-ray diffraction pattern of raw chrysotile with a typical basal distance of 7.36 Å, characteristic of raw chrysotile. 34,35 As described previously, 34 this sample has a characteristic diffraction peak positioned at 9.5° (2θ) (9.31Å), attributed to a small contamination with talc.…”

Section: Resultssupporting

confidence: 57%

“…34,35 The bands at 3451 and 1630 cm -1 were attributed to water molecules adsorbed to the chrysotile tubes. The bands at 1076, 1024 and 955 cm -1 were attributed to symmetric stretching vibrations of Si-O-Si and Si-O bonds.…”

Section: Resultsmentioning

confidence: 99%

“…The white disordered silica solid was obtained by treating chrysotile with hydrochloric acid, as previously described. 21,23 Iodosylbenzene (PhIO) was synthesized by hydrolysis of iodosylbenzenediacetate. 26 The solid was carefully dried under reduced pressure and kept at 5 °C.…”

Section: Methodsmentioning

confidence: 99%

“…[20][21][22] Chrysotile is the magnesium-based mineral analogous to kaolinite, and consists of sheets of brucitelike Mg(OH) 2 structure linked to sheets of silica, producing layers of the 1:1 group minerals. 20 The mismatch of the brucite-like octahedral sheet with the silica tetrahedral sheet causes the curvature of the layers, which can roll into tight tubes, the characteristic chrysotile fibers.…”

Section: Introductionmentioning

confidence: 99%

“…20 The mismatch of the brucite-like octahedral sheet with the silica tetrahedral sheet causes the curvature of the layers, which can roll into tight tubes, the characteristic chrysotile fibers. 21 A drastic leaching of chrysotile fibers by concentrated acid transforms this natural polymer by removing the brucite-like layer, resulting in an excellent source of hydrated disordered silica 23,24 with physico-chemical characteristics similar to silica gel.…”

Section: Introductionmentioning

confidence: 99%

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Catalytic activity in oxidation reactions of anionic iron(III) porphyrins immobilized on raw and grafted chrysotile

Nakagaki¹,

Castro²,

Machado³

et al. 2006

J. Braz. Chem. Soc.

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Crisotila natural e quimicamente modificada foi usada como matrizes para imobilização de ferroporfirinas de segunda geração. As atividades catalíticas dos sólidos obtidos foram avaliadas em reações de oxidação de cicloexano, usando iodosilbenzeno como oxidante. Os resultados de catálise foram analisados e comparados aos obtidos pela imobilização das mesmas ferroporfirinas em sílica funcionalizada com 3-APTS, derivadas do tratamento ácido da crisotila. Os resultados preliminares mostraram que os catalisadores são eficientes e seletivos para a obtenção de álcool.Natural and grafted chrysotile were used as matrices for the immobilization of second generation iron porphyrins. The catalysts obtained were evaluated in the oxidation reaction of cyclohexane, using iodosylbenzene as oxidant agent. The catalyst activity for different conditions was compared with results for the same porphyrins immobilized with 3-APTS grafted disordered silica, obtained from acid-leached chrysotile. Preliminary results have shown that high activity can be obtained with short reaction times, and that the reaction is specific for alcohol.

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Section: Resultssupporting

confidence: 57%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Catalytic activity in oxidation reactions of anionic iron(III) porphyrins immobilized on raw and grafted chrysotile

Nakagaki¹,

Castro²,

Machado³

et al. 2006

J. Braz. Chem. Soc.

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Novel phenyl‐POSS/polyurethane aqueous dispersions and their hybrid coatings

Zhang

et al. 2013

J of Applied Polymer Sci

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A facile and rapid preparation of 3-(2-aminoethylamino)propylheptaphenylPOSS (AA-POSS), a special phenyl-POSS that contains two functional amino groups (Scheme 1), is demonstrated by the corner-capping method. Then AA-POSS forms a series of novel phenyl-POSS=PU aqueous dispersions. The structure of AA-POSS has been confirmed by Si NMR, and ESI-MS. The POSS=PU hybrid films are studied by Fourier transform infrared spectrometer (FT-IR), gel permeation chromatography (GPC), scanning electron microscope (SEM), X-ray diffraction (XRD) spectra, differential scanning calorimetry (DSC) analysis, and thermal gravimetric analyzer (TGA). FT-IR and GPC are conducted to validate the chemical structure of the hybrid PU. The properties of hybrid films display significant changes with notable increases in T g , thermal properties, tensile strength, as well as surface hydrophobicity. These changes are attributed to the incorporation of novel POSS into PU. Moreover, these significant material property enhancements are achieved at low levels of POSS incorporation (only 4%).

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Synthesis of Fe‐doped chrysotile and characterization of the resulting chrysotile fibers

Bloise

Belluso

Barrese

et al. 2009

Cryst. Res. Technol.

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This study describes the formation of Fe-doped chrysotile fibers with partial and total substitution of Mg by Fe. Syntheses were carried out with various starting mixtures (oxides, pure synthetic forsterite) in an externally heated pressure vessel in controlled hydrothermal conditions: temperature, 270 -400 °C; pressure, 0.5 -2 kbar; duration of treatment 160 -480 hours. Pure synthetic forsterite was prepared by the flux growth technique. The starting material and run products were characterized by X-ray powder diffraction (XRPD), scanning and transmission electron microscopies combined with energy-dispersive spectrometry (SEM-EDS and TEM-EDS), differential scanning calorimetry (DSC) and thermogravimetry (TG). Variations observed in abundance and size of Fe-doped chrysotile fibers were attributed to different experimental conditions for their synthesis. However, morphological shape turned out to depend on the starting mixtures used. Since natural samples are often difficult to obtain in a sufficiently pure state, these synthetic and well-characterized Fedoped chrysotile fibers can be used for better understanding of the mechanisms involved in asbestos toxicity, as well as of the role of Fe in diseases induced by asbestos phases. These synthetic Fe-doped chrysotile fibers, together with non-toxicity testing, may also have potential for exploitation in industrial fields.

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Covalent grafting of phenylphosphonate groups onto layered silica derived from in situ-leached chrysotile fibers

Cited by 40 publications

References 30 publications

Catalytic activity in oxidation reactions of anionic iron(III) porphyrins immobilized on raw and grafted chrysotile

Catalytic activity in oxidation reactions of anionic iron(III) porphyrins immobilized on raw and grafted chrysotile

Novel phenyl‐POSS/polyurethane aqueous dispersions and their hybrid coatings

Synthesis of Fe‐doped chrysotile and characterization of the resulting chrysotile fibers

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