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Keywords = thiol-functionalized organosilicas

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14 pages, 2685 KB  
Article
Flexible Humidity Sensor Based on Au Nanoparticles/Organosilica-Containing Polyelectrolyte Composite
by Pi-Guey Su and Chih-Chang Hsu
Chemosensors 2023, 11(5), 291; https://doi.org/10.3390/chemosensors11050291 - 13 May 2023
Cited by 3 | Viewed by 2413
Abstract
A novel flexible humidity sensor incorporating gold nanoparticles (Au NPs) and a trifunctional organosilica compound has been developed through the integration of sol–gel processing, free radical polymerization, and self-assembly techniques. The trifunctional organosilica was initially synthesized by modifying (3-mercaptopropyl)trimethoxysilane (thiol-MPTMS) with 3-(trimethoxysilyl)propyl methacrylate [...] Read more.
A novel flexible humidity sensor incorporating gold nanoparticles (Au NPs) and a trifunctional organosilica compound has been developed through the integration of sol–gel processing, free radical polymerization, and self-assembly techniques. The trifunctional organosilica was initially synthesized by modifying (3-mercaptopropyl)trimethoxysilane (thiol-MPTMS) with 3-(trimethoxysilyl)propyl methacrylate (vinyl-TMSPMA). Subsequently, a hydrophilic polyelectrolyte, [3(methacryloylamino)propyl]trimethyl ammonium chloride (MAPTAC), was grafted onto the MPTMS-TMSPMA gel. The Au NPs were assembled onto the thiol groups present in the MPTMS-TMSPMA-MAPTAC gel network. The compositional and microstructural properties of the Au NPs/MPTMS-TMSPMA-MAPTAC composite film were investigated utilizing Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The presence of thiol groups and mesoporous silica skeletons ensured the stability of the humidity-sensing film on the substrate under highly humid conditions, while the hydrophilic groups functioned as humidity-sensitive sites. This innovative humidity sensor demonstrated high sensitivity, acceptable linearity, minimal hysteresis, and rapid response time across a broad range of working humidity levels. Based on the complex impedance spectra analysis, hydronium ions (H3O+) were determined to govern the conductance process of the flexible humidity sensor. Full article
(This article belongs to the Section Materials for Chemical Sensing)
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12 pages, 3100 KB  
Article
Hybrid Porous Microparticles Based on a Single Organosilica Cyclophosphazene Precursor
by Vanessa Poscher, George S. Pappas, Oliver Brüggemann, Ian Teasdale and Yolanda Salinas
Int. J. Mol. Sci. 2020, 21(22), 8552; https://doi.org/10.3390/ijms21228552 - 13 Nov 2020
Cited by 3 | Viewed by 2749
Abstract
Porous organosilica microparticles consisting of silane-derived cyclophosphazene bridges were synthesized by a surfactant-mediated sol-gel process. Starting from the substitution of hexachlorocyclotriphosphazene with allylamine, two different precursors were obtained by anchoring three or six alkoxysilane units, via a thiol-ene photoaddition reaction. In both cases, [...] Read more.
Porous organosilica microparticles consisting of silane-derived cyclophosphazene bridges were synthesized by a surfactant-mediated sol-gel process. Starting from the substitution of hexachlorocyclotriphosphazene with allylamine, two different precursors were obtained by anchoring three or six alkoxysilane units, via a thiol-ene photoaddition reaction. In both cases, spherical, microparticles (size average of ca. 1000 nm) with large pores were obtained, confirmed by both, scanning and transmission electron microscopy. Particles synthesized using the partially functionalized precursor containing free vinyl groups were further functionalized with a thiol-containing molecule. While most other reported mesoporous organosilica particles are essentially hybrids with tetraethyl orthosilicate (TEOS), a unique feature of these particles is that structural control is achieved by exclusively using organosilane precursors. This allows an increase in the proportion of the co-components and could springboard these novel phosphorus-containing organosilica microparticles for different areas of technology. Full article
(This article belongs to the Special Issue Ordered Mesoporous Materials)
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14 pages, 3475 KB  
Article
Thiol-Functionalized Ethylene Periodic Mesoporous Organosilica as an Efficient Scavenger for Palladium: Confirming the Homogeneous Character of the Suzuki Reaction
by María I. López, Dolores Esquivel, César Jiménez-Sanchidrián, Pascal Van Der Voort and Francisco J. Romero-Salguero
Materials 2020, 13(3), 623; https://doi.org/10.3390/ma13030623 - 30 Jan 2020
Cited by 6 | Viewed by 3456
Abstract
This work describes the synthesis of thiol-functionalized periodic mesoporous organosilicas (PMOs) prepared using the precursor 1-thiol-1,2-bis(triethoxysilyl)ethane, alone or mixed with 1,2-bis(triethoxysilyl)ethane. The thiol groups incorporated into the structure were found to be efficient for palladium binding. This has allowed these materials to be [...] Read more.
This work describes the synthesis of thiol-functionalized periodic mesoporous organosilicas (PMOs) prepared using the precursor 1-thiol-1,2-bis(triethoxysilyl)ethane, alone or mixed with 1,2-bis(triethoxysilyl)ethane. The thiol groups incorporated into the structure were found to be efficient for palladium binding. This has allowed these materials to be used as catalysts in the Suzuki cross-coupling reaction of bromobenzene and phenylboronic acid. Their performance has been compared to palladium-supported periodic mesoporous (organo)silicas and important differences have been observed between them. The use of different heterogeneity tests, such as hot filtration test and poisoning experiments, has provided a deep insight into the reaction mechanism and has confirmed that the reaction occurs in the homogeneous phase following a “release and catch” mechanism. Furthermore, the thiol-functionalized periodic mesoporous organosilica, synthesized using only 1-thiol-1,2-bis(triethoxysilyl)ethane as a precursor, has proven to be an efficient palladium scavenger. Full article
(This article belongs to the Special Issue Advances in Microporous and Mesoporous Materials)
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12 pages, 1767 KB  
Article
Sulfonic Acid Functionalization of Different Zeolites and Their Use as Catalysts in the Microwave-Assisted Etherification of Glycerol with tert-Butyl Alcohol
by Rafael Estevez, Ivan Iglesias, Diego Luna and Felipa M. Bautista
Molecules 2017, 22(12), 2206; https://doi.org/10.3390/molecules22122206 - 12 Dec 2017
Cited by 26 | Viewed by 6275
Abstract
The etherification of glycerol with tert-butyl alcohol in the liquid phase, over different sulfonic acid functionalized zeolites, has been studied. The reaction was carried out using microwaves as a way of heating, measured at autogenous pressure and without any solvent. Dealuminated HY [...] Read more.
The etherification of glycerol with tert-butyl alcohol in the liquid phase, over different sulfonic acid functionalized zeolites, has been studied. The reaction was carried out using microwaves as a way of heating, measured at autogenous pressure and without any solvent. Dealuminated HY and HZSM-5 zeolites by acid treatment were functionalized with two different organosilica precursors: 3-mercaptopropyltrimethoxysilane (M), which incorporates thiol groups, and 2-(4-chlorosulfonylphenyl)ethyltrimethoxysilane (C), which incorporates the sulfonic acid groups directly. The thiol groups were oxidized into sulfonic groups employing hydrogen peroxide. The textural and structural properties of the solids were studied by XRD and N2 adsorption–desorption isotherms, whereas the incorporation of the organosilica in the zeolites was studied by TGA and XPS. The novelty functionalization of M gave rise to solids with the highest acidity, and exhibited the highest yields with more substituted ethers (Yh-GTBE = 13%), at 75 °C and 15 min of reaction time. In addition to the acidity, the textural properties of the zeolites played an important role in their activity; HY, with the largest size of the channels, were more active than the HZSM-5. Full article
(This article belongs to the Special Issue Meeting of the Spanish Catalysis Society (SECAT’17))
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15 pages, 593 KB  
Article
Periodic Mesoporous Organosilica Functionalized with Sulfonic Acid Groups as Acid Catalyst for Glycerol Acetylation
by Els De Canck, Inmaculada Dosuna-Rodríguez, Eric M. Gaigneaux and Pascal Van Der Voort
Materials 2013, 6(8), 3556-3570; https://doi.org/10.3390/ma6083556 - 16 Aug 2013
Cited by 23 | Viewed by 7413
Abstract
A Periodic Mesoporous Organosilica (PMO) functionalized with sulfonic acid groups has been successfully synthesized via a sequence of post-synthetic modification steps of a trans-ethenylene bridged PMO material. The double bond is functionalized via a bromination and subsequent substitution obtaining a thiol functionality. [...] Read more.
A Periodic Mesoporous Organosilica (PMO) functionalized with sulfonic acid groups has been successfully synthesized via a sequence of post-synthetic modification steps of a trans-ethenylene bridged PMO material. The double bond is functionalized via a bromination and subsequent substitution obtaining a thiol functionality. This is followed by an oxidation towards a sulfonic acid group. After full characterization, the solid acid catalyst is used in the acetylation of glycerol. The catalytic reactivity and reusability of the sulfonic acid modified PMO material is investigated. The catalyst showed a catalytic activity and kinetics that are comparable with the commercially available resin, Amberlyst-15, and furthermore our catalyst can be recycled for several subsequent catalytic runs and retains its catalytic activity. Full article
(This article belongs to the Section Porous Materials)
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