In situ synthesis, characterization, and catalytic performance of tungstophosphoric acid encapsulated into the framework of mesoporous silica pillared clay

Li, Baoshan; Liu, Zhenxing; Han, Chunying; Ma, Wei; Zhao, Songjie

doi:10.1016/j.jcis.2012.03.067

Cited by 44 publications

(27 citation statements)

References 45 publications

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“…But for HPWFe‐MMTSi, an infrared absorption band was observed at around 815 cm ‐1 . This might be ascribed to the formation of Si‐O‐W bonds between MMTSi and HPWFe, demonstrating that HPWFe had been well encaged into the structural framework of MMTSi . These results indicated that the Keggin structure of HPWFe was successfully supported on MMTSi, as did the results of wide‐angle XRD.…”

Section: Resultsmentioning

confidence: 60%

“…Moreover, the hysteresis loop of the isotherm decreased as the HPWFe content increased. Figure S2 illustrates the proposed formation mechanism of the ordered mesoporous MMTSi and HPWFe‐MMTSi materials . As expected, MMTSi showed a high surface area of 638 m 2 g ‐1 , which was much higher than that of natural MMT (68 m 2 g ‐1 ), indicating that the mesoporous silica‐pillared MMT was well formed by the addition of TEOS.…”

Section: Resultsmentioning

confidence: 61%

“…For all the samples, the weight loss observed before 100°C was attributed to the loss of physically absorbed water molecules and the corresponding DTA curve in this region was endothermic . For HPWFe, the weight loss (about 4.18%) between 100 and 296°C was assigned to the loss of crystal water of the Keggin unit, corresponding to the endothermic peak centered at 211°C in the DTA curve . The final step of about 3.88% weight loss in the range of 296–570°C was assigned to the loss of acidic protons and the beginning of decomposition of the Keggin structure, corresponding to the endothermic peak centered at about 400°C in the DTA curve .…”

Section: Resultsmentioning

confidence: 96%

“…In the spectra of HPWFe, the broad band around 802 cm ‐1 could be attributed to v as (W‐O c ‐W) in the edge shared octahedral . In the spectrum of MMTSi, the band at 795 cm ‐1 was assigned to the symmetric stretching frequency of Si‐O‐Si . But for HPWFe‐MMTSi, an infrared absorption band was observed at around 815 cm ‐1 .…”

Section: Resultsmentioning

confidence: 97%

See 3 more Smart Citations

Iron(III)‐modified tungstophosphoric acid supported on silica‐pillared montmorillonite as catalysts for fructose conversion to methyl levulinate

Lai

Luo

Jiang

et al. 2017

J of Chemical Tech & Biotech

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BACKGROUND Because of the decline in conventional sources of energy and the increasing pollution, the fossil fuel based energy structures is being replaced by renewable energy based structures such as biomass energy. Among current biodiesel sources, methyl levulinate (ML) obtained from catalytic conversion of renewable carbohydrate with methanol has received a great deal of attention. Silica‐pillared montmorillonites (MMTSi) functionalized by iron‐modified tungstophosphoric acid (HPWFe) were prepared, and their physicochemical properties and catalytic effects on ML production studied. RESULTS Catalysts characterization demonstrated the high dispersion and Keggin structure of HPWFe in the framework of MMTSi. Effects of various reaction parameters and catalyst recycling on the reaction performance were studied to optimize fructose conversion. With 4‐HPWFe‐MMTSi as the catalyst, an optimized ML yield of around 74 mol% was obtained at 180°C for 1 h, and the recovered catalyst after calcination was found to retain high activity after being reused five times. CONCLUSION The prepared HPWFe‐MMTSi catalysts showed high porosity, perfect Brnsted‐Lewis acidity and high thermal stability, which made their catalytic activity for fructose conversion and catalyst reusability values higher than others reported in the literature. © 2017 Society of Chemical Industry

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Section: Resultsmentioning

confidence: 60%

Section: Resultsmentioning

confidence: 61%

Section: Resultsmentioning

confidence: 96%

Section: Resultsmentioning

confidence: 97%

See 2 more Smart Citations

Iron(III)‐modified tungstophosphoric acid supported on silica‐pillared montmorillonite as catalysts for fructose conversion to methyl levulinate

Lai

Luo

Jiang

et al. 2017

J of Chemical Tech & Biotech

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show abstract

“…Both Fe 3 O 4 at MCM-41/CPS and Fe 3 O 4 at MCM-41/APTS showed a three-step weight loss. The initial weight loss occurred at lower temperatures (below 156 • C) and it was attributed to the loss of residual water (Li et al, 2012). The second mass loss occurred at temperatures ranging from 156 • C to 417 • C and it was attributed to the loss of modifiers.…”

Section: Shape Size and Morphological Characteristics Ofmentioning

confidence: 99%

Characterization and optimization of mesoporous magnetic nanoparticles for immobilization and enhanced performance of porcine pancreatic lipase

et al. 2015

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In this paper, Fe3O4 nanoparticles coated with mesoporous silica were prepared successfully, noted as Fe3O4 at the mobile composition of matter No. 41 (MCM-41). Also, Fe3O4 at MCM-41 was grafted by both 3-aminopropyltriethoxysilane (APTS) and 3-chloropropyltriethoxysilane (CPS), noted as Fe3O4 at MCM-41/APTS and Fe3O4 at MCM-41/CPS. The compounds were characterized by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, vibrating sample magnetometry, thermogravimetry and N2 adsorption/desorption. Then, the enzyme, porcine pancreas lipase (PPL), was immobilized onto these modified nanoparticles by covalent attachment, physical adsorption and cross-linking, noted as Fe3O4 at MCM-41/CPS-PPL, Fe3O4 at MCM-41-PPL and Fe3O4 at MCM-41/APTS-PPL, respectively. The results showed that Fe3O4 at MCM-41/CPS was the best nanomaterial for PPL immobilization, exhibiting enhanced immobilization efficiency (maximum 96 %), maximum relative activity (up to 96 %), high stability and reusability (83 % 56 days and 86.7 % ten cycles). Additionally, it offered some other advantages, such as easy recycling and reuse, complying with the trend of green chemistry. Therefore, Fe3O4 at MCM-41/CPS in combination with a relevant method can be proposed for commercial applications.

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A new nanocomposite catalyst based on clay‐supported heteropolyacid for the green synthesis of 2,4,5‐trisubstituted imidazoles

Masteri‐Farahani

Ezabadi

Mazarei

et al. 2020

Applied Organom Chemis

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Intercalation of cetyltrimethylammonium (CTA +) cations within the nanolayers of montmorillonite (MMT) clay followed by reaction with Keggin-type phosphomolybdic acid (PMo) resulted in the synthesis of (CTA) 3 PMo-MMT nanocomposite catalyst. The prepared nanocomposite catalyst was characterized using different physicochemical methods such as Fourier-transform infrared and inductively coupled plasma-optical emission spectroscopies, X-ray diffraction, and nitrogen adsorption-desorption (Brunauer-Emmett-Teller method) analyses. Characterization techniques demonstrated the intercalation of (CTA) 3 PMo species into the nanolayers of MMT. The resulting (CTA) 3 PMo-MMT nanocomposite catalyst efficiently catalyzed the synthesis of 2,4,5-trisubstituted imidazoles under solvent-free conditions. The efficiency is due to the fact that the presence of CTA + species makes the nanocomposite catalyst hydrophobic and facilitates the accessibility of hydrophobic reactants to active sites in the course of the reaction. High activity and selectivity were achieved in the presence of the prepared nanocomposite catalyst. The nanocomposite catalyst was readily isolated from the reaction mixture using simple filtration, washed with ethanol, and recycled five times without a major loss of activity.

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In situ synthesis, characterization, and catalytic performance of tungstophosphoric acid encapsulated into the framework of mesoporous silica pillared clay

Cited by 44 publications

References 45 publications

Iron(III)‐modified tungstophosphoric acid supported on silica‐pillared montmorillonite as catalysts for fructose conversion to methyl levulinate

Iron(III)‐modified tungstophosphoric acid supported on silica‐pillared montmorillonite as catalysts for fructose conversion to methyl levulinate

Characterization and optimization of mesoporous magnetic nanoparticles for immobilization and enhanced performance of porcine pancreatic lipase

A new nanocomposite catalyst based on clay‐supported heteropolyacid for the green synthesis of 2,4,5‐trisubstituted imidazoles

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