scholarly journals Ionic Liquids: Efficient Media for the Lipase-Catalyzed Michael Addition

Molecules ◽  
2018 ◽  
Vol 23 (9) ◽  
pp. 2154 ◽  
Author(s):  
Yunchang Fan ◽  
Dongxu Cai ◽  
Xin Wang ◽  
Lei Yang
Keyword(s):  
Ionic Liquids ◽  
Lipase Activity ◽  
Michael Addition ◽  
Alkyl Chain ◽  
Hydroxyl Group ◽  
Domain Formation ◽  
High Chemical ◽  
Chemical Structures ◽  
Reaction Media ◽  
High Chemical Stability

Recently, ionic liquids (ILs) have been regarded as ideal media for non-aqueous bio-catalysis. In this work, the synthesis of warfarin by the lipase-catalyzed Michael addition in IL media and the parameters that affected the warfarin yield were investigated. Experimental results demonstrated that the chemical structures of the ILs were a major factor for influencing the warfarin yield. The ILs containing the NTf2– anion were suitable reaction media due to the high chemical stability of this anion. The incorporation of the hydroxyl group on the IL cation significantly improved the lipase activity due to the H2O-mimicking property of this group. The lipase activity decreased by increasing the alkyl chain length on the IL cation due to the non-polar domain formation of the IL cation at the active site entrance of lipase. The ILs and lipase could be reused no less than five times without reduction in the warfarin yield.

Hydration States of Cholinium Phosphate-Type Ionic Liquids as a Function of Water Content

2019 ◽  
Vol 72 (5) ◽  
pp. 392 ◽  
Author(s):  
Yohsuke Nikawa ◽  
Seiji Tsuzuki ◽  
Hiroyuki Ohno ◽  
Kyoko Fujita
Keyword(s):  
Ionic Liquids ◽  
Water Content ◽  
Alkyl Chain ◽  
Hydroxyl Group ◽  
Water Molecules ◽  
Hydroxyl Groups ◽  
Ion Structure ◽  
Activity Measurements ◽  
Microscopic Interactions ◽  
Dynamics Simulations

We investigated the hydration states of cholinium phosphate-type ionic liquids (ILs) in relation to ion structure, focusing on the influence of the hydroxyl group of the cation and the alkyl chain length of the anion. Water activity measurements provided information on the macroscopic hydration states of the hydrated ILs, while NMR measurements and molecular dynamics simulations clearly showed the microscopic interactions and coordination of the water molecules. The hydrogen bonding networks in these ILs were influenced by the anion structure and water content, and the mobility of water molecules was influenced by the number of hydroxyl groups in the cation and anion.

Comparative Studies on Synthesis of Imidazole Ionic Liquids and Their Solubility for Wood by Microwave

2010 ◽  
Vol 113-116 ◽  
pp. 1744-1748 ◽  
Author(s):  
Li Ying Guo ◽  
Mu Zhang
Keyword(s):  
High Pressure ◽  
Ionic Liquids ◽  
Mass Fraction ◽  
Wood Fiber ◽  
Hydroxyl Group ◽  
Wood Powder ◽  
Chemical Structures ◽  
High Pressure Studies ◽  
Before And After ◽  
Temperature And Pressure

The present work deals with the synthesis of various imidazole ionic liquids [BMIM]Cl, [AMIM]Cl, [AEIM]Cl, [HeEIM]Cl and [HeVIM]Cl, the chemical structures of ionic liquids by FTIR and 1HNMR, the pretreatment of wood powder as extracted with a mixture of benzene/ethanol or activated with 25% (mass fraction) NaOH under normal temperature and pressure, microwave and high pressure, studies the solubility of ionic liquids on the wood powder by microwave (90°C, 400w), and analyses the microstructure of the wood before and after dissolution as measured by SEM. The result shows that all the ionic liquids can dissolve the wood fiber directly, ionic liquids containing hydroxyl group exhibit better solubility. Wood powder pretreated with 25% NaOH under high pressure has the lowest crystallinity (2.4%) and the highest dissolution rate. The solubility of [HeVIM]Cl is the best, which approach to 21.6%.

scholarly journals Oat-hull cellulose nitrates for explosive compositions

2019 ◽  
Vol 487 (4) ◽  
pp. 391-395
Author(s):  
G. V. Sakovich ◽  
V. V. Budaeva ◽  
А. А. Korchagina ◽  
Yu. А. Gismatulina ◽  
N. V. Kozyrev ◽  
...  
Keyword(s):  
High Viscosity ◽  
Scanning Calorimetry ◽  
High Chemical ◽  
Oat Hulls ◽  
Mixed Acid ◽  
Chemical Structures ◽  
Chemical Purity ◽  
Cellulose Nitrates ◽  
Composite Explosives ◽  
High Chemical Stability

Cellulose nitrates similar in basic properties to high-viscosity lacquer-grade Colloxyline were synthesized by esterification of pulp with mixed acid. The pulp was isolated from the easily renewable domestic feedstock - oat hulls - the agro-industrial waste. The cellulose nitrate test samples were comparatively evaluated. Infrared and 13C NMR spectroscopies confirmed the chemical structures were identical. It was established by differentiated scanning calorimetry and ampule chromatography that the samples had a high chemical purity. The cellulose nitrates were found to have satisfactory impact and friction sensitivities of 50 mm and 1200 kgf/cm2 and exhibit a good chemical compatibility and a high chemical stability when blended with plasticizers. The findings suggest that it is advisable to use oat-hull cellulose nitrates as the component of composite explosives. 

Influence of hydroxyl group functionalization and alkyl chain length on physicochemical and antiwear properties of hexafluorophosphate imidazolium ionic liquids

2014 ◽  
Vol 66 (3) ◽  
pp. 443-451 ◽  
Author(s):  
Yanqiu Xia ◽  
Zhihong Wang ◽  
Yanxin Song
Keyword(s):  
Ionic Liquids ◽  
Chain Length ◽  
Corrosion Behavior ◽  
Friction And Wear ◽  
Alkyl Chain ◽  
Electrochemical Corrosion ◽  
Alkyl Chain Length ◽  
Hydroxyl Group ◽  
Content Type ◽  
Electrochemical Corrosion Behavior

Purpose – The aim of the present paper is that three long-chain hydroxyethyl alkylimidazolium hexafluorophosphate ionic liquids (ILs) were synthesized and evaluated as lubricants for steel-steel contacts at room temperature and boundary lubrication conditions. Hydroxyethyl functional group and alkyl chain length effect on the physicochemical and fretting tribological behaviors of the ILs was comparatively investigated, as compared to traditional dialkylimidazolium ILs. Design/methodology/approach – The fretting friction and wear tests were carried out using an Optimol SRV-IV oscillating reciprocating friction and wear tester. The worn surface was observed and analyzed by scanning electron microscope and X-ray photoelectron spectroscopy. The electrochemical corrosion behavior of copper disks in selected imidazolium-based ionic liquids was studied using a CHI660B electrochemical workstation. Findings – This can be seen by comparing the results for the non-hydroxyl ILs and hydroxyl ILs that the latter exhibited the littler friction coefficient, the smaller wear volume, although the latter electrochemical corrosion behavior of copper disks is slightly higher than the former. The results also revealed that the ILs with a longer alkyl chain displayed larger viscosities, better anti-corrosion capacities, higher hydrophobic properties and more excellent friction-reducing and anti-wear performance than those with a shorter alkyl chain. Originality/value – This work might offer new knowledge in the design and application of new ILs as lubricants; it also confirms some in-depth physicochemical questions, e.g. the function mechanism, the correlations between structure and performance. Additionally, a proposed interaction model between the ILs and the friction substrate has been given.

An efficient and rapid intramolecular aza-Michael addition of 2′-aminochalcones using ionic liquids as recyclable reaction media

2012 ◽  
Vol 53 (32) ◽  
pp. 4059-4061 ◽  
Author(s):  
M. Chelghoum ◽  
M. Bahnous ◽  
A. Bouraiou ◽  
S. Bouacida ◽  
A. Belfaitah
Keyword(s):  
Ionic Liquids ◽  
Michael Addition ◽  
Reaction Media

ChemInform Abstract: An Efficient and Rapid Intramolecular Aza-Michael Addition of 2′-Aminochalcones Using Ionic Liquids as Recyclable Reaction Media.

ChemInform ◽  
2012 ◽  
Vol 43 (47) ◽  
pp. no-no
Author(s):  
M. Chelghoum ◽  
M. Bahnous ◽  
A. Bouraiou ◽  
S. Bouacida ◽  
A. Belfaitah
Keyword(s):  
Ionic Liquids ◽  
Michael Addition ◽  
Reaction Media

Effect of alkyl chain length and hydroxyl group functionalization on the surface properties of imidazolium ionic liquids

2011 ◽  
Vol 13 (30) ◽  
pp. 13518 ◽  
Author(s):  
Alfonso S. Pensado ◽  
Margarida F. Costa Gomes ◽  
José N. Canongia Lopes ◽  
Patrice Malfreyt ◽  
Agílio A. H. Pádua
Keyword(s):  
Ionic Liquids ◽  
Surface Properties ◽  
Chain Length ◽  
Alkyl Chain ◽  
Alkyl Chain Length ◽  
Hydroxyl Group ◽  
Imidazolium Ionic Liquids

Synthesis, Characterization and Applications of Dicationic Ionic Liquids in Organic Synthesis

2020 ◽  
Vol 17 (4) ◽  
pp. 450-464
Author(s):  
Mohammad Javaherian ◽  
Seyyed Jafar Saghanezhad
Keyword(s):  
Ionic Liquids ◽  
Organic Synthesis ◽  
Chemical Properties ◽  
Physical And Chemical Properties ◽  
Dicationic Ionic Liquids ◽  
Physical And Chemical ◽  
Reaction Media ◽  
And Chemical Properties

Dicationic ionic liquids are an emerging group of Ionic Liquids (ILs) that are currently receiving much attention as green reaction media and catalysts. Because of a great number of possible combinations of cations and anions, the physical and chemical properties of dicationic ionic liquids are more tunable and broader than monocationic ILs. Therefore, their unique properties have made them the target of many applied and fundamental researches. Actually, dicationic ionic liquids are more effective and rather fascinating than traditional monocationic ILs. So, due to greater versatility and diversity, their applications in organic synthesis have been extensively grown. In this review, we have focused on the synthesis, characterization and applications of dicationic ionic liquids, especially, in organic synthesis.

scholarly journals Molecular-Level Investigation of Cycloaliphatic Epoxidised Ionic Liquids as a New Generation of Monomers for Versatile Poly(Ionic Liquids)

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1512
Author(s):  
Baris Demir ◽  
Gabriel Perli ◽  
Kit-ying Chan ◽  
Jannick Duchet-Rumeau ◽  
Sébastien Livi
Keyword(s):  
Ionic Liquids ◽  
Molecular Level ◽  
Computational Approach ◽  
Polymer Materials ◽  
Chemical Structures ◽  
Cycloaliphatic Epoxy ◽  
Polymer Models ◽  
Mechanical Performances ◽  
Dynamics Simulations ◽  
New Generation

Recently, a new generation of polymerised ionic liquids with high thermal stability and good mechanical performances has been designed through novel and versatile cycloaliphatic epoxy-functionalised ionic liquids (CEILs). From these first promising results and unexplored chemical structures in terms of final properties of the PILs, a computational approach based on molecular dynamics simulations has been developed to generate polymer models and predict the thermo–mechanical properties (e.g., glass transition temperature and Young’s modulus) of experimentally investigated CEILs for producing multi-functional polymer materials. Here, a completely reproducible and reliable computational protocol is provided to design, test and tune poly(ionic liquids) based on epoxidised ionic liquid monomers for future multi-functional thermoset polymers.

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