Chromatographic characterisation of ordered mesoporous silicas. Part II: Acceptor–donor properties

Grajek, H.; Paciura-Zadrożna, J.; Witkiewicz, Zygfryd

doi:10.1016/j.chroma.2010.02.029

Cited by 10 publications

(2 citation statements)

References 25 publications

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“…DN-values are calculated by calorimetric measurements from the sorption of the probe molecules (electron donor) onto SbCl 5 (electron acceptor). AN-values are derived by 31 P NMR measurements from the chemical shift of Et 3 PO (electron donor) in the presence of an electron acceptor [57][58][59][60]. The enthalpy of sorption ΔH sp ads is obtained by IGC (using at least three different temperatures) with the following equation:…”

Section: Inverse Gas Chromatography (Igc)mentioning

confidence: 99%

In situ synthesis and characterization of sulfonic acid functionalized hierarchical silica monoliths

Enke

Meyer

Wenzel

et al. 2020

J Sol-Gel Sci Technol

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Surface functionalization of porous materials with sulfonic acid (SO3H) groups is of particular interest in applications involving ion exchange, acidic catalysis and proton conduction. Macro-mesoporous silica monoliths are ideal support structures for these applications, as they combine advection-dominated mass transport in the macropores with short diffusion lengths and a large surface area (available for functionalization) in their mesoporous skeleton. Here, we report on SO3H functionalized sol–gel silica monoliths with bimodal pore systems exhibiting macro- and mesoporosity, prepared according to a simple, efficient in situ synthesis protocol. Based on the co-condensation approach, thiol groups were introduced homogeneously into the pore structure, followed by their oxidation to SO3H groups and the simultaneous removal of the template. The macropore size, specific surface area, and coverage with SO3H groups are easily adjusted in this synthesis route. Importantly, the hybrid monoliths have a substantially narrower mesopore size distribution (relative standard deviation ~25%) than conventional sol–gel materials (>40%) and can be engineered crack-free in a robust column design (suitable for high-pressure flow-through operation) with mean mesopore size down to ~7 nm. They are characterized by IR spectroscopy, thermogravimetry, and elemental analysis as well as 13C and 29Si solid state NMR to corroborate the simple, efficient combination of sol–gel-based material synthesis, surface functionalization, and template removal (i.e., polymer extraction). Complementary, inverse gas chromatography is presented as a new approach to characterize the incorporated SO3H groups via surface energy analysis and particularly resolve changes in the Lewis acid–base characteristics engendered by that functionalization.

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Section: Inverse Gas Chromatography (Igc)mentioning

confidence: 99%

In situ synthesis and characterization of sulfonic acid functionalized hierarchical silica monoliths

Enke

Meyer

Wenzel

et al. 2020

J Sol-Gel Sci Technol

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“…A straight line with the slope of K A is obtained by plotting

Δ H_{normalA}^{SP} / {AN}^{*}

against DN/AN* where DN denotes the donor number given by Gutmann and AN* is the acceptor number modified by Fowkes . The values of the constants K A and K D calculated in this way are theoretically independent on the column temperature in spite of the fact that some researchers have proposed temperature can change acidic properties of a material . Although precise values were given in the literature, relative errors of K D can be larger because it is determined from the intercept of the straight line.…”

Section: Theorymentioning

confidence: 99%

Determination of surface energies and acidity‐basicity numbers of protonated and deprotonated forms of poly(sulfonic acid diphenyl aniline) by inverse gas chromatography

Yazıcı

Karaman

2015

Polymer Engineering & Sci

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Protonated form of poly(sulfonic acid diphenyl aniline) (p‐PSDA) was synthesized through oxidative chemical polymerization of sodium salt of diphenylamino‐4‐sulfonic acid in hydrochloric acid and then, its deprotonated form (PSDA) was obtained by neutralization with aqueous ammonium hydroxide solution. The samples were characterized by thermal analysis and Fourier Transform Infrared, Ultraviolet‐visible, 1H‐NMR spectroscopy techniques. Their dispersive surface energies as well as surface acidity and basicity were determined by inverse gas chromatography at temperatures between 313 and 353 K. The dispersive surface energy of p‐PSDA was found to be considerably lower but it increased with temperature while that of PSDA was close to those of conventional polymers and decreased slightly with temperature. According to the Schreiber's procedure, the surfaces of p‐PSDA and PSDA were found to be acidic and amphoteric, respectively. It was observed from the electron microscope images p‐PSDA chains can form self‐organized circular polydisperse micro‐sized aggregates in aqueous solutions while PSDA cannot self‐organize to form individual aggregates. POLYM. ENG. SCI., 55:1246–1254, 2015. © 2015 Society of Plastics Engineers

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Investigation of Physicochemical Characteristics of Aspergillus niger Biomass and Examination of Its Ability to Separate Butyl Acetate Isomers

Isik,

Bilgi

2024

Appl Biochem Biotechnol

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Chromatographic characterisation of ordered mesoporous silicas. Part II: Acceptor–donor properties

Cited by 10 publications

References 25 publications

In situ synthesis and characterization of sulfonic acid functionalized hierarchical silica monoliths

In situ synthesis and characterization of sulfonic acid functionalized hierarchical silica monoliths

Determination of surface energies and acidity‐basicity numbers of protonated and deprotonated forms of poly(sulfonic acid diphenyl aniline) by inverse gas chromatography

Investigation of Physicochemical Characteristics of Aspergillus niger Biomass and Examination of Its Ability to Separate Butyl Acetate Isomers

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