Search results for "Ionic"

POSS nanostructures in catalysis

2020

Polyhedral oligomeric silsesquioxanes (POSS) are organic-inorganic hybrid molecules piquing the interest of researchers thanks to their synergistic features. The great versatility of POSS nanostructures arises from the easy tunability of peripheral organic moieties combined with the high thermal and chemical stability of the inner inorganic core. In this review, we highlight the use of POSS nanostructures as molecular precursors for the synthesis of homogeneous and heterogeneous catalysts able to promote many processes including alkene epoxidation, C-C bond formation, CO2 conversion, "click reactions", hydrogenation, and ethylene polymerisation, among others. In this scenario, POSS units fo…

Modelling of natural synthetic polyelectrolyte interactions in natural waters by using SIT, Pitzer and Ion Pairing approaches

2006

Abstract In this paper SIT and Pitzer models are used for the first time to describe the interactions of natural and synthetic polyelectrolytes in natural waters. Measurements were made potentiometrically at 25 °C in single electrolyte media, such as Et 4 NI and NaCl (for fulvic acid 0.1  − 1 S single salt ” BA, with cation B and anion A representing all the major cations (Na + , K + , Mg 2+ , Ca 2+ ) and anions (Cl − , SO 4 2− ) in natural sea water, respectively. The ion pair formation model was also applied to fulvate and alginate in artificial sea water by examining the interaction of polyanions with the single sea water cation. Results were compared with those obtained from previous sp…

Cationic and Zwitterionic Polymerizable SurfactantsQuaternary Ammonium Dialkyl Maleates. 2. Emulsion Polymerization of Styrene and Butyl Acrylate

1998

Polymerizable cationic and zwitterionic dialkyl maleates with different hydrophobic chain lengths (R = C10H21, C12H25, C16H33, C18H37) and different counterions (I, Br, HSO4) for the cationic hydrophilic part, as well as some similar surfactants, dialkyl succinates, were used in batch and seeded emulsion polymerization of styrene and butyl acrylate. All surfactants, when used in emulsion polymerization, provide good stability to the styrene/butyl acrylate latices. A styrene/butyl acrylate latex prepared with sodium dodecyl sulfate (SDS) was used as a reference. Some stability tests for latices were performed, and the glass transition temperatures, as well as the molecular weights of the pol…

Hydrophobically Modified Halloysite Nanotubes as Reverse Micelles for Water-in-Oil Emulsion.

2015

An easy strategy to obtain inorganic reverse micelles based on halloysite nanotubes (HNTs) and alkyltrimethylammonium bromides has been developed. The selective modification of the HNTs external surface with cationic surfactants endows to generate tubular nanostructures with a hydrophobic shell and a hydrophilic cavity. The influence of the surfactants alkyl chain on the HNTs functionalization degree has been investigated. The dynamic behavior of the surfactant/HNT hybrids in solvents with variable polarity has been correlated to their affinity toward hydrophobic media explored through partition experiments. The water-in-oil emulsion is able to solubilize copper sulfate, proving the incorpo…

Macrocyclic peptides in anionic polymers of amino acid N-carboxylic anhydrides.

1976

Characterization of gas phase aggregates of bis(2-ethylhexyl)sulfosuccinate (AOT) and divalent metal ions. Elimination of radical species in the deco…

2012

Structure and properties of even-electron anionic species formed by bis(2-ethylhexyl)sulfosuccinate (AOT) and divalent metal ions (MII) with stoichiometry [AOTMIICl2]– have been investigated by using electrospray ionization and different mass spectrometry techniques, such as high resolution, accurate mass measurements, collision-induced dissociation (CID) multiple-stage mass spectrometry. Owing to CID, eliminations of neutrals, mainly consisting in hydrochloric acid, 2-ethyl-1-hexene and 2-ethylhexanol, and an unexpected loss of an alkyl radical have been observed. The radical anions [C4HO6SMIICl]–• so produced have been characterized by MS3 experiments. Density functional theory calculatio…

Properties of new asymmetrically quaternized dicationic ammonium based room-temperature ionic liquids with ether functionality

2013

Eleven asymmetrically quaternized dicationic ammonium-based room-temperature ionic liquids (DRTILs) with bis(trifluoromethanesulfonyl)imide (TFSI) were synthesized and characterized, along with 11 analogous dibromide precursors. Two-step synthesis was used to diquaternize tetramethyl-1,3-propanediamine and 2-(dimethylamino)-ethyl ether amines with a variety of alkyl and ether functionalized side chain groups (R1 ≠ R2). Each salt contain 1 to 3 ether groups located either in a linkage or in a side chain moieties. Structural and thermoanalytical properties, water content, and viscosity have been characterized using, for example, NMR, mass spectrometry (MS), X-ray diffraction, and thermal anal…

Group 14 Metalloles, Ionic Species and Coordination Compounds

2009

1 Introduction 2 Synthesis 3 Organic Chemical Properties of Group 14 Metalloles 4 Polymeric Silole-Containing π-Conjugated Systems 5 Ionic Species and Coordination Compounds 6 Addendum 7 Conclusion 8 Acknowledgements Keywords: five-membered heterocyclic dienes; heterocyclopentadienes - heteroles or metalloles; group 14 metalloles, ionic species and coordination compounds; gas-phase pyrolysis of silacyclopent-3-enes; organometallic dihalide reaction with dilithio reagent; group 14 metalloles; HOMO stabilization; polymeric silole-containing pi-conjugated systems

FT-IR investigation of the state of iron (III) chloride clusters confined in AOT reverse micelles dispersed in carbon tetrachloride

2007

The state of the water-soluble salt iron(III) chloride in AOT reverse micelles dispersed in carbon tetrachloride has been investigated by FT-IR spectroscopy. Interestingly, while the entrapment of a lot of water-soluble inorganic salts in AOT reverse micelles requires preliminarily the presence of significant amounts of water within the micellar core, solubilization of FeCl3 occurs without the need to add water in the micellar solution reaching the very high solubility value, expressed as the maximum salt-to-surfactant molar ratio, of 1.30. The analysis of the spectral features of the investigated samples leads to hypothesize that iron(III) chloride is confined within the reverse micellar c…

Controlling the Polymer Microstructure in Anionic Polymerization by Compartmentalization.

2018

An ideal random anionic copolymerization is forced to produce gradient structures by physical separation of two monomers in emulsion compartments. One monomer (M) is preferably soluble in the droplets, while the other one (D) prefers the continuous phase of a DMSO-in-cyclohexane emulsion. The living anionic copolymerization of two activated aziridines is thus confined to the DMSO compartments as polymerization occurs selectively in the droplets. Dilution of the continuous phase adjusts the local concentration of monomer D in the droplets and thus the gradient of the resulting copolymer. The copolymerizations in emulsion are monitored by real-time 1 H NMR kinetics, proving a change of the re…