Ionic Liquids in Asymmetric Synthesis: An Overall View from Reaction Media to Supported Ionic Liquid Catalysis

ChemCatChem ◽  
2018 ◽  
Vol 10 (15) ◽  
pp. 3173-3205 ◽  
Author(s):  
Babak Karimi ◽  
Mina Tavakolian ◽  
Maryam Akbari ◽  
Fariborz Mansouri
Membranes ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 359
Author(s):  
László Koók ◽  
Piroska Lajtai-Szabó ◽  
Péter Bakonyi ◽  
Katalin Bélafi-Bakó ◽  
Nándor Nemestóthy

Hydrophobic ionic liquids (IL) may offer a special electrolyte in the form of supported ionic liquid membranes (SILM) for microbial fuel cells (MFC) due to their advantageous mass transfer characteristics. In this work, the proton and ion transfer properties of SILMs made with IL containing imidazolium cation and [PF6]− and [NTf2]− anions were studied and compared to Nafion. It resulted that both ILs show better proton mass transfer and diffusion coefficient than Nafion. The data implied the presence of water microclusters permeating through [hmim][PF6]-SILM to assist the proton transfer. This mechanism could not be assumed in the case of [NTf2]− containing IL. Ion transport numbers of K+, Na+, and H+ showed that the IL with [PF6]− anion could be beneficial in terms of reducing ion transfer losses in MFCs. Moreover, the conductivity of [bmim][PF6]-SILM at low electrolyte concentration (such as in MFCs) was comparable to Nafion.


2021 ◽  
Vol 08 ◽  
Author(s):  
Maryam Shirzad ◽  
Mitra Nasiri ◽  
Nader Daneshvar ◽  
Farhad Shirini ◽  
Hassan Tajik

Aim and objective: In this work, we have prepared two bis-dicationic ionic liquids with the same cationic core (Bis-imidazole) and different counter-anions using sulfuric acid and perchloric acids. After that, the efficiency and ability of these compounds as catalysts were investigated and compared in the promotion of Knoevenagel condensation and synthesis of benzo[b]pyran derivatives to see the effect of the anionic counter-part in the reaction. Material and method: In a 25 mL round-bottomed flask, a mixture of aldehyde (1.0 mmol), 1,3-cyclodicarbonyl (2.0 mmol) and the desired amount of the mentioned acidic ionic liquids was heated at 90°C in the absence of solvent (Reaction A) or In a 25 mL round-bottomed flask, a mixture of aldehyde (1.0 mmol), 1,3-cyclodicarbonyl (1.0 mmol), malononitrile, (1.1 mmol) and optimized amounts of the ionic liquid in water (3.0 mL) was heated at 80°C (Reaction B) for the appropriated time. After the completion of the reactions which were monitored by TLC (n-hexane: EtOAc; 3:1), 10 mL of water was added and the mixture was stirred for 2 minutes. Then, the products were separated by filtration and were washed several times with water. After drying, the pure products were obtained while there was no need to further. Results: Comparison of the obtained results from both of the ionic liquids revealed that [H2-Bisim][HSO4]2 because of its more acidic structure had a more catalytic activity for the preparation of 1,8-dioxo-octahydro-xanthene derivatives but [H2-Bisim][ClO4]2 was relatively more efficient for the synthesis of tetrahydrobenzo[b]pyran derivatives since the stronger acidic nature of [H2-Bisim][HSO4]2 may prevent the simple activation of malononitrile in the reaction media. Conclusion: In this study, we have introduced efficient methods for the synthesis of 1,8-dioxo-octahydro-xanthene and tetrahydrobenzo[b]pyran derivatives in the presence of catalytic amounts of [H2-Bisim][ClO4]2 and [H2-Bisim][HSO4]2 These methods have several advantages such as ease of preparation and handling of the catalysts, high reaction rates, excellent yields, eco-friendly procedures and simple work-up.


2005 ◽  
Vol 83 (1) ◽  
pp. 16-20 ◽  
Author(s):  
Xuesen Fan ◽  
Xueyuan Hu ◽  
Xinying Zhang ◽  
Jianji Wang

A green procedure for the synthesis of xanthenedione derivatives (3) through InCl3·4H2O-promoted condensation of aldehydes (1) and 5,5-dimethyl-1,3-cyclohexanedione (2) in ionic liquids is described in this paper. This novel method has such advantages as operational simplicity and environmental benignancy together with enhanced atom utilization. Moreover, the reaction media and the catalyst can be recovered conveniently and reused effectively for at least six times.Key words: ionic liquid, xanthenedione derivatives, indium trichloride, green synthesis.


Polymers ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3704
Author(s):  
Yaroslav L. Kobzar ◽  
Ghania Azzouz ◽  
Hashim Albadri ◽  
Jocelyne Levillain ◽  
Isabelle Dez ◽  
...  

In this work, the design and characterization of new supported ionic liquid membranes, as medium-temperature polymer electrolyte membranes for fuel-cell application, are described. These membranes were elaborated by the impregnation of porous polyimide Matrimid® with different synthesized protic ionic liquids containing polymerizable vinyl, allyl, or methacrylate groups. The ionic liquid polymerization was optimized in terms of the nature of the used (photo)initiator, its quantity, and reaction duration. The mechanical and thermal properties, as well as the proton conductivities of the supported ionic liquid membranes were analyzed in dynamic and static modes, as a function of the chemical structure of the protic ionic liquid. The obtained membranes were found to be flexible with Young’s modulus and elongation at break values were equal to 1371 MPa and 271%, respectively. Besides, these membranes exhibited high thermal stability with initial decomposition temperatures > 300 °C. In addition, the resulting supported membranes possessed good proton conductivity over a wide temperature range (from 30 to 150 °C). For example, the three-component Matrimid®/vinylimidazolium/polyvinylimidazolium trifluoromethane sulfonate membrane showed the highest proton conductivity—~5 × 10−2 mS/cm and ~0.1 mS/cm at 100 °C and 150 °C, respectively. This result makes the obtained membranes attractive for medium-temperature fuel-cell application.


Catalysts ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1227 ◽  
Author(s):  
Olga Bartlewicz ◽  
Izabela Dąbek ◽  
Anna Szymańska ◽  
Hieronim Maciejewski

This mini-review briefly describes the recent progress in the design and development of catalysts based on the presence of ionic liquids. In particular, the focus was on heterogeneous systems (supported ionic liquid (IL) phase catalysts (SILPC), solid catalysts with ILs (SCILL), porous liquids), which due to the low amounts of ionic liquids needed for their production, eliminate basic problems observed in the case of the employment of ionic liquids in homogeneous systems, such as high price, high viscosity, and efficient isolation from post-reaction mixtures.


2018 ◽  
Vol 15 (8) ◽  
pp. 1124-1146 ◽  
Author(s):  
Navjeet Kaur

Background: The synthesis of N-polyheterocycles by environmentally benign method is highly attractive but challenging proposition. New strategies have been developed for the preparation of polycyclic heterocycles in the last decades. In this review article, the synthesis of nitrogen containing six-membered polycyclic heterocyclic compounds is presented with the application of ionic liquids. This contribution focuses on the literature related to the total synthesis of six-membered N-polyheterocycles. Objective: Ionic liquids not only acted as environmentally benign reaction media but also as catalysts which afforded the very promising replacements of traditional molecular solvents in organic chemistry due to their stability, non-flammability, non-volatility and ease of recyclability. Ionic liquids are utilized in metal catalyzed reactions in place of organic solvents in the last years. It has attracted considerable attention in recent years. Ionic liquids acted as alternatives of organic solvents and these ILs are environment friendly. Conclusion: In the area of green chemistry ionic liquid assisted synthesis is a very promising technique which afforded a flexible platform for the formation of heterocycles. The influence of ILs on the development of efficient and new synthetic protocols over the last decade for the construction of N-polyheterocycles is featured in this review article. These synthetic strategies will continue to attract more attention and will find a wide range of applications in organic synthesis. In conclusion, ionic liquids assisted syntheses have become an efficient and powerful tool in organic chemistry quickly.


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