Pore Sizes of Solids

Halász, I.; Martin, Kornél

doi:10.1002/anie.197809011

Cited by 171 publications

(65 citation statements)

References 29 publications

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“…Based on the work of van Kreveld and Hoed [9] and of Halµsz and Martin, [7,10] one can calculate the exclusion diameter of a pore for such a polymer from M w = 10.87F r 1. 7 and M w = 2.25F 1.7 , respectively. However, the theory is only true for narrow molecular weight distributions (PDI !…”

Section: Resultsmentioning

confidence: 99%

“…The reagents used and their amounts are summarized in Table 1 and provided monoliths with a substantial fraction (32 %) of micro-and mesopores, that is, pores with an average pore size of < 10 nm, as evidenced by inverse size exclusion chromatography (ISEC) [7] measurements (Figure 1). The volume fraction of pores (e p ), the volume fraction of interparticle void volume (e z ), the total porosity (e t ), the average pore diameter (F m ), and the pore volume (V p ) of the parent monolith are summarized in Table 1.…”

Section: Resultsmentioning

confidence: 99%

“…As a rule of thumb, to be penetrated by a polymer, a pore must have a diameter approximately 2.5 times larger than the hydrodynamic diameter of the polymer. [7] For the hydrolysis of the epoxy groups inside the pores, we chose a sulfonated polyA C H T U N G T R E N N U N G (styrene) (i.e., poly(sty-…”

Section: Resultsmentioning

confidence: 99%

“…Inverse size exclusion chromatography (ISEC): The volume fractions of the inter-microglobule porosity (e z ), the pore porosity (e p ), the total porosity (e t ), the pore volume (V p ), and the mean pore diameter (F m ) of the monolithic columns were characterized by ISEC [7] as described elsewhere. [6a, 23] Hydrolysis of the epoxy groups within pores of > 7 nm: The epoxide groups of porous polymer rods were hydrolyzed by flushing the monolithic column with a solution of poly(styrenesulfonic acid) (M w = 69 400 g mol À1 , 4.5 wt % in water) for 15 min at a flow rate of 0.3 mL min À1 .…”

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confidence: 99%

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Ring‐Opening Metathesis Polymerization Based Pore‐Size‐Selective Functionalization of Glycidyl Methacrylate Based Monolithic Media: Access to Size‐Stable Nanoparticles for Ligand‐Free Metal Catalysis

Bandari

Höche

Prager

et al. 2010

Chemistry A European J

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Monolithic polymeric supports have been prepared by electron-beam-triggered free-radical polymerization using a mixture of glycidyl methacrylate and trimethylolpropane triacrylate in 2-propanol, 1-dodecanol, and toluene. Under appropriate conditions, phase separation occurred, which resulted in the formation of a porous monolithic matrix that was characterized by large (convective) pores in the 30 μm range as well as pores of <600 nm. The epoxy groups in pores of >7 nm were hydrolyzed by using poly(styrenesulfonic acid) (Mw = 69,400 g mol(-1), PDI=2.4). The remaining epoxy groups inside pores of <7 nm were subjected to aminolysis with norborn-5-en-2-ylmethylamine (2) and provided covalently bound norborn-2-ene (NBE) groups inside these pores. These NBE groups were then treated with the first-generation Grubbs initiator [RuCl2 (PCy3 )2 (CHPh)]. These immobilized Ru-alkylidenes were further used for the surface modification of the small pores by a grafting approach. A series of monomers, that is, 7-oxanorborn-5-ene-2,3-dicarboxylic anhydride (3), norborn-5-ene-2,3-dicarboxylic anhydride (4), N,N-di-2-pyridyl-7-oxanorborn-5-ene-2-carboxylic amide (5), N,N-di-2-pyridylnorborn-5-ene-2-carboxamide (6), N-[2-(dimethylamino)ethyl]bicyclo[2.2.1]hept-5-ene-2-carboxamide (7), and dimethyl bicyclo[2.2.1]hept-5-en-2-ylphosphonate (8), were used for this purpose. Finally, monoliths functionalized with poly-5 graft polymers were used to permanently immobilize Pd(2+) and Pt(4+), respectively, inside the pores. After reduction, metal nanoparticles 2 nm in diameter were formed. The palladium-nanoparticle-loaded monoliths were used in both Heck- and Suzuki-type coupling reactions achieving turnover numbers of up to 167,000 and 63,000, respectively.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Ring‐Opening Metathesis Polymerization Based Pore‐Size‐Selective Functionalization of Glycidyl Methacrylate Based Monolithic Media: Access to Size‐Stable Nanoparticles for Ligand‐Free Metal Catalysis

Bandari

Höche

Prager

et al. 2010

Chemistry A European J

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“…Halµsz and Martin [36] demonstrated the use of inverse size-exclusion chromatography (SEC) for the determination of internal porosity of the packing inside LC columns. In SEC, sample mixtures that are dissolved in the mobile phase can be separated according to their different molecular sizes [37].…”

Section: Analysis Of Interparticle Bed Porosity With Polystyrene Stanmentioning

confidence: 99%

Packing density of slurry‐packed capillaries at low aspect ratios

Ehlert

Rösler

Tallarek³

2008

J of Separation Science

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The average interparticle voidage or porosity (epsilon(inter)) in cylindrical capillaries is studied in dependence on the column diameter (d(c)) to particle diameter (d(p)) ratio for 5 < d(c)/d(p) < 50. Using optimized slurry and packing solvents, high pressure and ultrasonication, 5 mum-sized porous C18-silica particles were slurry-packed into fused-silica capillaries having ids from 30 to 250 mum. Packing densities are assessed by a polystyrene standard which is size-excluded from the intraparticle pore space of the packings. For d(c)/d(p) > 35 densely packed beds are realized (epsilon(inter) = 0.36-0.37), while for decreasing aspect ratios an exponential increase in epsilon(inter )is observed reaching epsilon(inter ) approximately 0.47 at d(c)/d(p) = 5. This behaviour is ascribed to a combination of the geometrical wall effect operating in the direct vicinity of the column wall, caused by the inability of the particles to form a dense packing against the hard surface of the column wall, and particle characteristics like the size distribution, shape and surface roughness. Results are compared with the literature data to address also the importance of absolute particle size in studying structure-transport relations in packed beds in dependence on the aspect ratio d(c)/d(p).

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Characterization of crosslinked, macroporous, monosized polymer particles

Nyhus¹,

Hagen²,

Berge³

2000

J. Appl. Polym. Sci.

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Macroporous, monosized poly(meta-divinylbenzene) and poly(para-divinylbenzene) beads have been prepared by the two-step activated swelling method with toluene or 2-ethylhexanoic acid as pore-forming agents. The type of divinylbenzene isomer as well as the type of porogen has a large effect on both physical and chemical properties of the monodisperse beads. Large pores are obtained with 2-ethylhexanoic acid as porogen while beads prepared in the presence of toluene consist of only small pores and exhibit a shrinking behavior upon drying. The beads have considerable amounts of residual vinyl groups at the end of polymerization, as determined by bromination and Fourier transform IR analysis. The morphology and texture of the particles have been investigated by scanning electron microscopy and atomic force microscopy.

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Pore Sizes of Solids

Cited by 171 publications

References 29 publications

Ring‐Opening Metathesis Polymerization Based Pore‐Size‐Selective Functionalization of Glycidyl Methacrylate Based Monolithic Media: Access to Size‐Stable Nanoparticles for Ligand‐Free Metal Catalysis

Ring‐Opening Metathesis Polymerization Based Pore‐Size‐Selective Functionalization of Glycidyl Methacrylate Based Monolithic Media: Access to Size‐Stable Nanoparticles for Ligand‐Free Metal Catalysis

Packing density of slurry‐packed capillaries at low aspect ratios

Characterization of crosslinked, macroporous, monosized polymer particles

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