Results 31 to 40 of about 12,249 (253)

A Remarkably Efficient Phase-Transfer Catalyzed Amination of α-Bromo-α, β-Unsaturated Ketones in Water

open access: yesHeteroatom Chemistry, 2021
Tandem conjugate addition–alkylation reaction of various amines with α-bromo-α, β-unsaturated ketones resulted in near-quantitative conversions into the corresponding aziridines when the reaction was carried out in the presence of 10 mol% of phase ...
Alemayehu Mekonnen, Alemu Tesfaye
doaj   +1 more source

Tetraalkylammonium and phosphonium salt for asphaltene dispersion; experimental studies on interaction mechanisms

open access: yesEgyptian Journal of Petroleum, 2022
Asphaltenes deposition is one of the most severe problems in the petroleum industry, imposing high costs on oil producer companies. The use of chemical dispersants reduces the risk of asphaltene deposition.
Shirin Baghersaei   +3 more
doaj   +1 more source

Ammonium Salts as Curing Agents to Obtain Ionic Epoxy Resins With a Thermoplastic‐to‐Thermoset Transition

open access: yesAdvanced Materials, EarlyView.
Ionic epoxy networks are prepared using ammonium salts as hardeners, leading to a two‐stage curing process with a thermoplastic‐like intermediate. This uncommon behavior enables extrusion and fabrication of thermoplastic prepregs that can be cured into thermoset composites.
Izabela Kurowska   +10 more
wiley   +1 more source

Synthesis and anticorrosive activity of tert-amines containing cycloacetal or gem-dichlorocyclopropane fragments and quaternary ammonium salts on their basis

open access: yesТонкие химические технологии
Objectives. The work set out to synthesize tertiary amines comprising derivatives of morpholine and piperidine containing a 1,3-dioxolane or gem-dichlorocyclopropane fragment, as well as quaternary ammonium salts based on them.
Yu. G. Borisova   +4 more
doaj   +1 more source

Structure and mechanical properties of polyamide 6/Brazilian clay nanocomposites

open access: yesMaterials Research, 2009
Recent interest in polymer/organoclays nanocomposites systems is motivated by the possibility of achieving enhanced properties and added functionality at lower clay loading as compared to conventional micron size fillers.
Amanda Melissa Damião Leite   +5 more
doaj   +1 more source

Synthesis and Catalytic Activity of Bifunctional Phase-Transfer Organocatalysts Based on Camphor

open access: yesMolecules, 2023
Ten novel bifunctional quaternary ammonium salt phase-transfer organocatalysts were synthesized in four steps from (+)-camphor-derived 1,3-diamines. These quaternary ammonium salts contained either (thio)urea or squaramide hydrogen bond donor groups in ...
Luka Ciber   +6 more
doaj   +1 more source

Eutectozymes as Soft Hybrid Materials for Advanced Biocatalysis

open access: yesAdvanced Materials, EarlyView.
Eutectozymes are sustainable hybrid materials that embed a GOx–HRP cascade within hydrophobic eutectogels featuring a dual supramolecular–covalent network. This architecture preserves native enzyme structure and stability, enables efficient heterogeneous biocatalysis in aqueous media, and positions eutectogels as robust platforms for next‐generation ...
Manuel Eduardo Martinez Cartagena   +10 more
wiley   +1 more source

Antifungal activity of gemini quaternary ammonium salts

open access: yesMicrobiological Research, 2013
A series of gemini quaternary ammonium chlorides and bromides with various alkyl chain and spacer lengths was synthesized. The most active compounds against fungi were chlorides with 10 carbon atoms within the hydrophobic chain. Among these compounds were few with no hemolytic activity at minimal inhibitory concentrations.
Obłąk, Ewa   +3 more
openaire   +2 more sources

Positively Charged Polymer‐Brush MOFs for Large‐Area, Pressure‐Resistant Gas Separation Membranes

open access: yesAdvanced Materials, EarlyView.
A universal POPA strategy enables positively charged polymer‐brush MOFs with self‐adaptive interfacial interlocking to resist aggregation under fast processing. This design ensures seamless dispersion within large‐area selective layers, achieving 1 m‐wide roll‐to‐roll fabrication of pressure‐resistant MMCMs with tunable CO2 separation performance ...
Yi Yang   +11 more
wiley   +1 more source

Quaternary ammonium salt as initiator for vinyl polymerization

open access: yesJournal of Polymer Science, 1958
AbstractBinary mixtures of amines and alkyl (or aralkyl) chlorides were used as the initiators for the polymerizations of several acrylic monomers and styrene. A parallelism was found between the catalytic actions of the mixtures and their quaternary salt formations.
Takayuki Fueno   +3 more
openaire   +2 more sources

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