Blend membranes based on N1-alkyl-substituted imidazolium functionalized polymers and aromatic polyethers: influence of N1-alkyl substituent on properties and alkaline stability

2021 ◽  
Author(s):  
A. Tsagdi ◽  
M. Dimitriou ◽  
D. Druvari ◽  
V. Deimede
Keyword(s):  
Alkyl Substituent ◽  
Functionalized Polymers ◽  
Alkaline Stability ◽  
Blend Membranes

scholarly journals Blend membranes of polybenzimidazole and an anion exchange ionomer (FAA3) for alkaline water electrolysis: Improved alkaline stability and conductivity

2018 ◽  
Vol 564 ◽  
pp. 653-662 ◽  
Author(s):  
Anastasiia Konovalova ◽  
Hyemi Kim ◽  
Sangwon Kim ◽  
Ahyoun Lim ◽  
Hyun Seo Park ◽  
...  
Keyword(s):  
Anion Exchange ◽  
Water Electrolysis ◽  
Alkaline Water Electrolysis ◽  
Alkaline Water ◽  
Alkaline Stability ◽  
Blend Membranes

scholarly journals Aliphatic Anion Exchange Ionomers with Long Spacers and No Ether Links by Ziegler–Natta Polymerization: Properties and Alkaline Stability

Molecules ◽  
2022 ◽  
Vol 27 (2) ◽  
pp. 395
Author(s):  
Raul Andres Becerra-Arciniegas ◽  
Riccardo Narducci ◽  
Gianfranco Ercolani ◽  
Luca Pasquini ◽  
Philippe Knauth ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Ionic Conductivity ◽  
Anion Exchange ◽  
Exchange Capacity ◽  
Ether Linkage ◽  
Ion Exchange Capacity ◽  
Alkaline Stability ◽  
Fuel Cell Electrode ◽  
Blend Membranes ◽  
Cell Electrode

In this work we report the synthesis of poly(vinylbenzylchloride-co-hexene) copolymer grafted with N,N-dimethylhexylammonium groups to study the effect of an aliphatic backbone without ether linkage on the ionomer properties. The copolymerization was achieved by the Ziegler–Natta method, employing the complex ZrCl4 (THF)2 as a catalyst. A certain degree of crosslinking with N,N,N′,N′-tetramethylethylenediamine (TEMED) was introduced with the aim of avoiding excessive swelling in water. The resulting anion exchange polymers were characterized by 1H-NMR, FTIR, TGA, and ion exchange capacity (IEC) measurements. The ionomers showed good alkaline stability; after 72 h of treatment in 2 M KOH at 80 °C the remaining IEC of 76% confirms that ionomers without ether bonds are less sensitive to a SN2 attack and suggests the possibility of their use as a binder in a fuel cell electrode formulation. The ionomers were also blended with polyvinyl alcohol (PVA) and crosslinked with glutaraldehyde. The water uptake of the blend membranes was around 110% at 25 °C. The ionic conductivity at 25 °C in the OH− form was 29.5 mS/cm.

Highly stable polysulfone anion exchange membranes incorporated with bulky alkyl substituted guanidinium cations

2019 ◽  
Vol 4 (5) ◽  
pp. 1039-1047 ◽  
Author(s):  
Boxin Xue ◽  
Fen Wang ◽  
Jifu Zheng ◽  
Shenghai Li ◽  
Suobo Zhang
Keyword(s):  
Anion Exchange ◽  
Steric Hindrance ◽  
Alkyl Substituent ◽  
Anion Exchange Membranes ◽  
Alkaline Stability

Free and bulky alkyl substituent groups with large steric hindrance dramatically improve the alkaline stability of guanidiniums.

Design, Synthesis and Antiplasmodial Evaluation of Sulfoximine-triazole Hybrids as Potential Antimalarial Prototypes

2019 ◽  
Vol 15 (6) ◽  
pp. 685-692 ◽  
Author(s):  
Tommy F. Mabasa ◽  
Babatunde Awe ◽  
Dustin Laming ◽  
Henok H. Kinfe
Keyword(s):  
Alkyl Substituent ◽  
Antimalarial Drugs ◽  
Significant Activity ◽  
Design Synthesis ◽  
Antimalarial Agents ◽  
Falciparum Strain ◽  
Physiological Properties ◽  
Resistant Strains ◽  
Cytotoxicity Activities ◽  
Drug Resistant Strains

Background:Malaria, caused by the deadly Plasmodium falciparum strain, claims the lives of millions of people annually. The emergence of drug-resistant strains of P. falciparum to the artemisinin-based combination therapy (ACT), the last line of defense against malaria, is worrisome and urges for the development of new chemo-types with a new mode of action. In the search of new antimalarial agents, hybrids of triazoles and other known antimalarial drugs have been reported to possess better activity than either of the parent compounds administered individually. Despite their better activity, no hybrid antimalarial drugs have been developed so far.Objective:In the hope of developing new antimalarial prototypes, we propose the design, synthesis and antimalarial evaluation of novel sulfoximine-triazole hybrids owing to their interesting biological and physiological properties.Methods:The sulfoximine part of the hybrid will be synthesized via imidation of the corresponding sulfoxide. Propargylation of the NH moiety of the sulfoximine followed by copper-catalyzed click chemistry with benzyl azide was envisaged to provide the target sulfoximine-triazole hybrids.Results:Five novel sulfoximine-triazole hybrids possessing various substituents on the sulfoximine moiety have been successfully synthesized and evaluated for their antiplasmodial and cytotoxicity activities. The results revealed that the co-presence of the sulfoximine and triazole moieties along with a lipophilic alkyl substituent on the sulfur atom impart significant activity.Conclusion:Sulfoximine-triazole hybrids could be used as a prototype for the synthesis of new derivatives with better antiplasmodial activities.

Kinetic Study of Hydrolysis of Benzoates. Part XXVI. Variation of the Substituent Effect with Solvent in Alkaline Hydrolysis of Substituted Alkyl Benzoates

2006 ◽  
Vol 71 (11-12) ◽  
pp. 1557-1570 ◽  
Author(s):  
Vilve Nummert ◽  
Mare Piirsalu ◽  
Ilmar A. Koppel
Keyword(s):  
Kinetic Study ◽  
Alkaline Hydrolysis ◽  
Rate Constants ◽  
Substituent Effect ◽  
Substituent Effects ◽  
Alkyl Substituent ◽  
Solvent Parameters ◽  
Substituent Constants ◽  
Hydrolysis Of ◽  
Main Factor

The second-order rate constants k2 (dm3 mol-1 s-1) for the alkaline hydrolysis of substituted alkyl benzoates C6H5CO2R have been measured spectrophotometrically in aqueous 0.5 M Bu4NBr at 50 and 25 °C (R = CH3, CH2Cl, CH2CN, CH2C≡CH, CH2C6H5, CH2CH2Cl, CH2CH2OCH3, CH2CH3) and in aqueous 5.3 M NaClO4 at 25 °C (R = CH3, CH2Cl, CH2CN, CH2C≡CH). The dependence of the alkyl substituent effects on different solvent parameters was studied using the following equations:      ∆ log k = c0 + c1σI + c2EsB + c3∆E + c4∆Y + c5∆P + c6∆EσI + c7∆YσI + c8∆PσI     ∆ log k = c0 + c1σ* + c2EsB + c3∆E + c4∆Y + c5∆P + c6∆Eσ* + c7∆Yσ* + c8∆Pσ* .  ∆ log k = log kR - log kCH3. σI and σ* are the Taft inductive and polar substituent constants. E, Y and P are the solvent electrophilicity, polarity and polarizability parameters, respectively. In the data treatment ∆E = ES - EH2O , ∆Y = YS - YH2O , ∆P = PS - PH2O were used. The solvent electrophilicity, E, was found to be the main factor responsible for changes in alkyl substituent effects with medium. When σI constants were used, variation of the polar term of alkyl substituents with the solvent electrophilicity E was found to be similar to that observed earlier for meta and para substituents, but twice less when σ* constants were used. The steric term for alkyl substituents was approximately independent of the solvent parameters.

Cyanoacrylate Inhibitors of the Hill Reaction V. The Effect of Chirality on Inhibitor Binding

1987 ◽  
Vol 42 (6) ◽  
pp. 684-689 ◽  
Author(s):  
John L. Huppatz ◽  
John N. Phillips
Keyword(s):  
Phenyl Ring ◽  
Alkyl Substituent ◽  
Receptor Site ◽  
Optically Active ◽  
Hill Reaction ◽  
Inhibitor Binding ◽  
Level Of Activity ◽  
The Difference ◽  
The Hill

Optically active α-methylbenzylamino 2-cyanoacrylic esters were synthesized and assayed as inhibitors of the Hill reaction in isolated pea chloroplast fragments. The 5-isomers were more potent inhibitors than the S-isomers with discriminations of from ten to greater than 100-fold being observed. A β-alkyl substituent in the cyanoacrylate molecule affected both the level of activity and the difference in activity between the isomers. An α,α-dimethylbenzylamino derivative was also active at about the same level as the corresponding α-methylbenzylamino racemate. This result could be explained in terms of the orientation of the phenyl ring in the receptor site. Replacement of the α-methylbenzylamino group by other α-alkyl and α-phenyl substituents had little effect on activity. However, an α-benzyl group was beneficial.

scholarly journals Selective recovery of rare earth elements with ligand-functionalized polymers in fixed-bed adsorption columns

2021 ◽  
Vol 265 ◽  
pp. 118472
Author(s):  
Jonathan C. Callura ◽  
Qingyang Shi ◽  
David A. Dzombak ◽  
Athanasios K. Karamalidis
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Fixed Bed ◽  
Functionalized Polymers ◽  
Selective Recovery ◽  
Fixed Bed Adsorption
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