Catalytic effect of fluoride on silica polymerization at neutral pH

Sandoval-Díaz, Luis Ernesto; Coy-Barrera, Ericsson; Trujillo, Carlos

doi:10.1007/s11144-011-0407-z

Cited by 4 publications

(2 citation statements)

References 18 publications

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“…Generally, fluoride anion catalyzed reactions via strong H bonding of the fluoride anion to the reactant protic molecule, with resulting enhancement of the nucleophilicity of the protic compound. Fluoride anion as a catalyst can assist many reactions such as alkylation and arylation of phenols, catechols, alcohols, and other compounds, esterification reactions, Michael addition reactions, aldol condensations, Knoevenagel reactions, intramolecular cyclization reactions, oxidations, nucleophilic fluorination reactions, multicomponent reactions, and some special polymerizations . Fluoride ion facilely breaks CSi and OSi bond to remove protecting groups .…”

Section: Introductionmentioning

confidence: 99%

Simple and efficient anionic polymerization of N‐phenylmaleimide with fluorides as an initiator

Sun

Novak

2019

J of Applied Polymer Sci

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The facile anionic polymerization of N-phenylmaleimide (N-PMI) using fluorides as an initiator has been discovered and systematically investigated. Effect of different solvents such as dioxane, tetrahydrofuran, dichloromethane (DCM), dimethyl sulfoxide (DMSO), N-methylpyrrolidone, acetonitrile, toluene, and acetone and effect of anionic initiators such as tetra-n-butylammonium fluoride (TBAF), cesium fluoride, and potassium fluoride have been studied. The kinetics of polymerization using TBAF as an initiator in DMSO is also studied. Some of the resulting poly(PMI)s are characterized by gel permeation chromatography, solubility test, attenuated total reflection-Fourier transform infrared, nuclear magnetic resonance (NMR), and 13 C-NMR spectral analysis. The thermal behaviors are studied by thermogravimetric and differential scanning calorimetric analysis. A proposed polymerization mechanism is also discussed. Our results show fluoride can effectively induce the polymerization of N-PMI in various solvents under very mild conditions with good to excellent yields.

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Section: Introductionmentioning

confidence: 99%

Simple and efficient anionic polymerization of N‐phenylmaleimide with fluorides as an initiator

Sun

Novak

2019

J of Applied Polymer Sci

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“…According to the general view they are made of indistinguishably complex polymer siloxane rings and/or chains hence little effort has been made until very recently to elucidating real molecular structures [6,9]. However, in the course of the past five years or so, suddenly several laboratories initiated experimental and computer modeling studies to explore the gelling process and gel structures at the molecular level [10][11][12]. Our own research groups relied mainly on 29 Si NMR, FTIR and Raman spectroscopic data to characterize the molecular constitutions of variously made silica gels [1,2,[13][14][15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Estimation for the Si-O Structures Based on the Homology Concept

Nakane

Halász

2015

AMR

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The first atomically resolved transmission electron microscopic (TEM) pictures of silica gels showed visible differences between their molecular densities (MD), which might be the molecular foundation of their distinctly different macroscopic properties, like porosity, surface area, fragility, etc. [1, 2]. Thus, learning to control MD promises the first time to add rational chemical design to the largely empirical synthesis methods of silica gels with desirable physical properties. However there is no known method for the quantitative comparison of molecular densities of these amorphous materials. We report in this paper a new numerical image-analyzing method, utilizing the mathematical theory of homology [3], which allows to measure quantitatively the molecular density of silica gels from their high resolution TEM pictures.

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