scholarly journals Synthesis and Properties of Magnetic Aryl-Imidazolium Ionic Liquids with Dual Brønsted/Lewis Acidity

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2539 ◽  
Author(s):  
Jui-Cheng Chang ◽  
Che-Hsuan Yang ◽  
I-Wen Sun ◽  
Wen-Yueh Ho ◽  
Tzi-Yi Wu
Keyword(s):  
Ionic Liquids ◽  
Lewis Acidity ◽  
Brønsted Acidity ◽  
Good Thermal Stability ◽  
Magnetic Ionic Liquids ◽  
Good Solubility ◽  
Brönsted Acidity ◽  
Lewis Acidic Sites ◽  
Acidic Sites ◽  
Electron Withdrawing Group

A series of unique tunable aryl-imidazolium magnetic ionic liquids (MILs) with dual acidity that contain both Brønsted and Lewis acidic sites (abbreviated as B-L MILs) were synthesized and characterized using nuclear magnetic resonance and mass spectrometry. Physical properties, such as thermal properties, magnetic susceptibility, and Brønsted and Lewis acidity, were measured. These properties were found to depend on the cation structure. These B-L MILs had good solubility in many organic solvents, good thermal stability, and low melting points, and exhibited magnet-like behavior. For these B-L MILs, the Brønsted acidity was measured using ultraviolet-visible (UV-Vis), and the Lewis acidity was measured using Fourier transform infrared spectroscopy (FTIR). The results showed that B-L MILs with an electron-withdrawing group in the aryl-imidazolium moiety had higher Brønsted acidity, whereas those with an electron-donating group had higher Lewis acidity. This type of ionic liquid, with both Brønsted and Lewis acidic sites, is expected to be a useful solvent and catalyst for organic reactions.

scholarly journals Reactivity and Reusability of Mesoporous Alumina Nanoparticles Modified with Sulfuric Acid and Niobic Acid in the Alkylation of Resorcinol

2014 ◽  
Vol 4 (1) ◽  
Author(s):  
Zainab Ramli ◽  
Hadi Nur ◽  
Sheela Chandren
Keyword(s):  
Sulfuric Acid ◽  
High Surface ◽  
Mesoporous Alumina ◽  
Alumina Nanoparticles ◽  
Lewis Acidity ◽  
Methyl Tert Butyl Ether ◽  
Solid Catalyst ◽  
Brønsted Acidity ◽  
Brönsted Acidity ◽  
Niobic Acid

With the development of large molecule hydrocarbon processes, mesoporous alumina which possesses high surface area with narrow pore size distribution has received a great deal of attention. However, its acid properties lack Bronsted acidity and showed only Lewis acid sites, making it an inactive solid catalyst in the alkylation of resorcinol, a reaction which requires the usage of solid acid catalysts with both Bronsted and Lewis acidity. In this study, in order to introduce Bronsted acidity to mesoporous alumina, sulfuric acid (H2SO4) and niobic acid (Nb2O5.nH2O) are introduced to the alumina. The reactivity of mesoporous alumina nanoparticles (MAN), Nb2O5.nH2O/MAN and H2SO4/MAN were tested out on the alkylation of resorcinol with methyl tert-butyl ether. No product was obtained using pure MAN, while both H2SO4/MAN and Nb2O5.nH2O/MAN managed to produce butylated resorcinol. Mesoporous alumina nanoparticles incorporated with sulfuric acid produced a greater amount of dibutylated resorcinol, which theoretically is a better antioxidant compared to monobutylated resorcinol. The reusability of the H2SO4/MAN catalyst was also better as dibutylated product was still obtained even in the second use. This indicates that sulfuric acid has created a more stable and also higher strength of Bronsted acidity in alumina as compared to niobic acid.

Effect of Brønsted Acidity on Ion Conduction in Fluorinated Acetic Acid and N-Methylimidazole Equimolar Mixtures as Pseudo-protic Ionic Liquids

2020 ◽  
Vol 124 (49) ◽  
pp. 11157-11164
Author(s):  
Hikari Watanabe ◽  
Nana Arai ◽  
Yasuo Kameda ◽  
Richard Buchner ◽  
Yasuhiro Umebayashi
Keyword(s):  
Acetic Acid ◽  
Ionic Liquids ◽  
Brønsted Acidity ◽  
Protic Ionic Liquids ◽  
Ion Conduction ◽  
Brönsted Acidity

Brønsted acidity in deep eutectic solvents and ionic liquids

2018 ◽  
Vol 206 ◽  
pp. 365-377 ◽  
Author(s):  
Andrew P. Abbott ◽  
Sahar S. M. Alabdullah ◽  
Azhar Y. M. Al-Murshedi ◽  
Karl S. Ryder
Keyword(s):  
Ionic Liquids ◽  
Deep Eutectic Solvents ◽  
Glass Electrode ◽  
Brønsted Acidity ◽  
Ph Values ◽  
Brönsted Acidity ◽  
Indicator Dye

Relative pH values are calculated using an indicator dye and a glass electrode, and they are found to provide consistent results.

Metal-free hydroxyl functionalized quaternary phosphine type ionic liquids polymer for cycloaddition of CO2 and epoxide

2021 ◽  
Author(s):  
Wuying Zhang ◽  
Qian He ◽  
Yaju Chen ◽  
Rongchang Luo ◽  
Xiantai Zhou ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Synergistic Effect ◽  
Hydroxyl Group ◽  
Brønsted Acidity ◽  
Metal Free ◽  
Brönsted Acidity ◽  
Free Hydroxyl ◽  
Alkylation Reactions

Quaternary phosphine type hypercrosslinked polymer catalysts were successfully fabricated with the Friedel-Crafts alkylation reactions, benefit from synergistic effect between the Brönsted acidity of the hydroxyl group and nucleophilic of the...

Physicochemical properties, Brönsted acidity and ecotoxicity of imidazolium-based organic salts: Non-toxic variants of protic ionic liquids

2018 ◽  
Vol 269 ◽  
pp. 178-186 ◽  
Author(s):  
Sabahat Sardar ◽  
Cecilia Devi Wilfred ◽  
Asad Mumtaz ◽  
Jean-Marc Leveque ◽  
Amir Sada Khan ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Physicochemical Properties ◽  
Brønsted Acidity ◽  
Protic Ionic Liquids ◽  
Organic Salts ◽  
Brönsted Acidity

Spectroscopic determination of relative Brønsted acidity as a predictor of reactivity in aprotic ionic liquids

2015 ◽  
Vol 51 (30) ◽  
pp. 6651-6654 ◽  
Author(s):  
Ariel I. Horowitz ◽  
Paola Arias ◽  
Matthew J. Panzer
Keyword(s):  
Ionic Liquids ◽  
Reaction Rates ◽  
Spectroscopic Determination ◽  
Bronsted Acids ◽  
Brønsted Acidity ◽  
Brönsted Acidity ◽  
Relative Acidity

FTIR-enabled titration of pyridine with Brønsted acids in aprotic ionic liquids successfully predicts relative acidity and reaction rates.

Brønsted Acidity and the Medium: Fundamentals with a Focus on Ionic Liquids

ChemPhysChem ◽  
2011 ◽  
Vol 12 (9) ◽  
pp. 1622-1632 ◽  
Author(s):  
Lynn M. Mihichuk ◽  
Gordon W. Driver ◽  
Keith E. Johnson
Keyword(s):  
Ionic Liquids ◽  
Brønsted Acidity ◽  
Brönsted Acidity

Mechanistic insight to acidity effects of Ga/HZSM-5 on its activity for propane aromatization

RSC Advances ◽  
2015 ◽  
Vol 5 (112) ◽  
pp. 92222-92233 ◽  
Author(s):  
He Xiao ◽  
Junfeng Zhang ◽  
Peng Wang ◽  
Zhenzhou Zhang ◽  
Qingde Zhang ◽  
...  
Keyword(s):  
Synergistic Effect ◽  
Lewis Acidity ◽  
Brønsted Acidity ◽  
Brönsted Acidity ◽  
Mechanistic Insight ◽  
Propane Aromatization ◽  
Strong Lewis Acidity

Mechanistic insight to the synergistic effect between Brønsted acidity and strong Lewis acidity of Ga/HZSM-5 on propane aromatization activity.

scholarly journals The Proton Dissociation of Bio-Protic Ionic Liquids: [AAE]X Amino Acid Ionic Liquids

Molecules ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 62
Author(s):  
Ting He ◽  
Cheng-Bin Hong ◽  
Peng-Chong Jiao ◽  
Heng Xiang ◽  
Yan Zhang ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Amino Acid ◽  
Acid Ester ◽  
Amino Acid Ester ◽  
Acidity Function ◽  
Brønsted Acidity ◽  
Protic Ionic Liquids ◽  
Indicator Method ◽  
Pka Values ◽  
Brönsted Acidity

[AAE]X composed of amino acid ester cations is a sort of typically “bio-based” protic ionic liquids (PILs). They possess potential Brønsted acidity due to the active hydrogens on their cations. The Brønsted acidity of [AAE]X PILs in green solvents (water and ethanol) at room temperature was systematically studied. Various frameworks of amino acid ester cations and four anions were investigated in this work from the viewpoint of structure–property relationship. Four different ways were used to study the acidity. Acid dissociation constants (pKa) of [AAE]X determined by the OIM (overlapping indicator method) were from 7.10 to 7.73 in water and from 8.54 to 9.05 in ethanol. The pKa values determined by the PTM (potential titration method) were from 7.12 to 7.82 in water. Their Hammett acidity function (H0) values (0.05 mol·L−1) were about 4.6 in water. In addition, the pKa values obtained by the DFT (proton-transfer reactions) were from 7.11 to 7.83 in water and from 8.54 to 9.34 in ethanol, respectively. The data revealed that the cationic structures of [AAE]X had little effect and the anions had no effect on the acidity of [AAE]X. At the same time, the OIM, PTM, Hammett method and DFT method were reliable for determining the acidic strength of [AAE]X in this study.

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