Dual Acidic Ionic Liquid Research Articles

Pyridinium-based dual acidic ionic liquid supported on the pectin for efficient synthesis of pyrazoles

In this work, we developed for the first time a pectin-supported dual acidic pyridinium ionic liquid with rich sulfonic acid groups as an efficient catalyst for the synthesis of pyrazole derivatives. Pectin (Pec) as a biopolymer is initially modified with 2,6-diamino pyridine (DAP) to obtain the Pec-DAP nanoparticles. The produced Pec-DAP reacts with 1,4-butane sultone (BS), and followed by treatment with a H2SO4 solution to afford the Pec-DAP-BS catalyst. The structure of the catalyst is characterized by different techniques. This catalyst presented a remarkable activity as a metal-free catalytic system for the three-component synthesis of pyrazoles from aldehydes, phenylhydrazines, and malononitrile due to the cooperative effect of dual acidic sites. Under optimized conditions, pyrazole derivatives are obtained with high turnover frequencies (TOF) up to 184.7 h−1 and excellent yields (92–96%) in short reaction times (15–50 min) in aqueous ethanol as a green solvent. Moreover, the catalyst is used in at least five cycles without significant loss of activity, and its heterogeneous nature is confirmed by the hot-filtration test.

Core-shell magnetic nanomaterial grafted spongy-structured poly (ionic liquid): A recyclable brönsted acid catalyst for biodiesel production

Construction of an efficient and separable Bronsted acid catalyst to realize one-pot conversion from low-value oils to biodiesel has been a hot and difficult spot in recent years. Herein, a novel magnetically recyclable catalyst was fabricated by grafting the sponge-like structure of poly (ionic liquid) on the surface of support Fe3O4/SiO2. The grafting copolymerization of dual-acidic ionic liquid (sulfonated vinylimidazolium ionic liquid) on the Fe3O4/SiO2 was beneficial to enhance the strong acidity of the magnetic carrier and also made dual-acidic ionic liquid own excellent separation characteristics. The characterization results of the prepared composite showed that a sponge-like structure of poly(ionic liquid) was wrapped on the outer surface of Fe3O4@SiO2, thereby providing more active sites to reactants. Meanwhile, the catalyst possessed high magnetization value (14.3 emu/g) that resulted in the simple and rapid separation from the reaction system through an external magnetic field. Benefiting from the synergy effect between dual-acidic poly(ionic liquids) and magnetic carrier, Fe3O4@SiO2@PIL exhibited good catalytic performance with the oleic acid conversion of 92.1 % and the methyl oleate yield of 92.1 %. Besides, the recycled catalyst showed no significant loss in the catalytic activity after repeated use for six times.

Grafting copolymerization of dual acidic ionic liquid on core-shell structured magnetic silica: A magnetically recyclable Brönsted acid catalyst for biodiesel production by one-pot transformation of low-quality oils

The objective of the current research is to prepare an efficient and magnetically separable Brönsted acid catalyst for one-pot transformation of low-quality oils to biodiesel. In this premise, the core–shell structured magnetic composites were firstly prepared by coating of silica shells on magnetic Fe3O4 nanoparticles. Thereafter, the grafting copolymerization of dual acidic ionic liquids (ILs, 1-vinyl-3-(3-sulfopropyl)imidazolium hydrogen sulfate as an monomer and 1.4-butanediyl-3,3′-bis-1-vinylimidazoliu hydrogen sulfate as a cross-linker agent) on the magnetic silica composite was conducted to impart the richer Brönsted acidic functionality on the support. The detailed catalyst characterization results showed that the magnetic silica support was really formed, and moreover the polymeric acidic ILs were successfully grafted on the magnetic support. The so-prepared solid catalyst had a large surface acidity (3.93 meq H+/g) and strong magnetism (27.5 emu/g). Benefiting from the synergism between the polymeric ILs and magnetic porous support, this developed catalyst displayed good catalytic activities toward both the transesterification of soybean oil and esterification of free fatty acids (FFAs), which endowed it to be a robust solid acid catalyst for one-pot biodiesel production from low-quality acidic oils. The solid catalyst could be simply recovered by an external magnet with minor loss of catalytic activity within five cycles, and further showed insensitivities to moisture and FFAs present in the feedstocks, possessing both economic and environmental advantages for the application in biodiesel production especially from the low-quality oils.

Copper-doped mesoporous silica supported dual acidic ionic liquid as an efficient and cooperative reusability catalyst for Biginelli reaction

A series of MCM-41 supported functionalized ionic liquids doped with copper species were prepared, characterized and evaluated as catalysts in the Biginelli reaction. Most of these supported ionic liquids perform well in the reaction, especially the multifunctional copper coordinated MCM-41 supported heterogeneous catalysts (0.5)IL-TiCl5@MCM-41@Cu(15) and (0.5)IL-HSO4@MCM-41@Cu(15). The catalytic tests revealed that (0.5)IL-HSO4@MCM-41@Cu(15) was the best and powerful catalyst in the Biginelli reaction for the preparation of 3,4-dihydropyrimidinones with high to excellent yields. The catalyst can be easily separated from the reaction mixture by filtration and reused in six consecutive cycles without significant loss in catalytic activity.

Production of medium-chain structured lipids using dual acidic ionic liquids supported on Fe3O4@SiO2 composites as magnetically recyclable catalysts

The purpose of this work is to develop robust and stable catalysts for production of low-calorie lipids in a heterogeneous manner to meet the demand of green food engineering. To accomplish this, magnetic Fe3O4@SiO2 support was prepared, and then dual acidic ionic liquid, 1-(propyl-3-sulfonate)imidazolium hydrogen sulfate, was bound onto the magnetic support via covalent attachments to prepare solid acid catalysts. The so-prepared solid catalyst was characterized by Brönsted acidity determination, elemental analysis, XRD, FT-IR, TEM, VSM, and N2 adsorption-desorption techniques. Results showed that the ionic liquid was successfully immobilized on the Fe3O4@SiO2 support, and the structure of magnetic support remained unchangeable after the functionalization. This solid catalyst displayed a strong magnetic responsiveness, allowing it to be easily separated by an external magnet. By using this magnetic catalyst, soybean oil was acidolyzed with caprylic and capric acids to produce medium-chain structured lipids. The medium-chain fatty acids incorporated into triacylglycerols were determined by GC techniques, and the total incorporations of caprylic and capric acids were found to be 42.5% over the catalyst. Moreover, the solid catalyst could be reused efficiently for several cycles without appreciable loss of its activity.

One-pot synthesis of benzopyrans catalyzed by silica supported dual acidic ionic liquid under solvent-free conditions

Abstract A mild and efficient method was developed for the preparation of tetrahydrobenzo[b]pyrans through a one-pot three-component condensation of aldehydes, malononitrile and dimedone in the presence of silica supported dual acidic ionic liquid (DAIL@SiO2) as a powerful catalyst under solvent-free conditions. This procedure is characterized by mild reaction conditions, simple workup and environmental friendliness. Moreover, the catalyst could be recycled for five times with only a slight loss of catalytic activity.

Brønsted–Lewis dual acidic ionic liquid immobilized on mesoporous silica materials as an efficient cooperative catalyst for Mannich reactions

Novel mesoporous silica supported ILs have been prepared and successfully applied as a heterogeneous catalyst in Mannich reactions.

Magnetic Nanoparticles Supported Acidic Ionic Liquid as a Highly Active and Reusable Catalyst for Esterification

A magnetic nanoparticles supported dual acidic ionic liquid catalyst was prepared via anchoring 3-sulfobutyl-1-(3-propyltriethoxysilane) imidazolium hydrogen sulfate onto the surface of silica-coated Fe3O4 nanoparticles. And this novel supported acidic ionic liquid catalyst showed good catalytic performance in esterification. More importantly, the catalyst could be easily recovered by an external magnet and reused six times without significant loss of catalytic activity.

ChemInform Abstract: Nanosilica‐Supported Dual Acidic Ionic Liquid as a Heterogeneous and Reusable Catalyst for the Synthesis of Flavanones under Solvent‐Free Conditions.

AbstractVarious flavones are obtained by cyclization of the corresponding hydroxychalcones using the nanosilica‐supported dual acidic ionic liquid based on 1‐methyl‐3‐(4‐sulfobutyl)imidazolium hydrogen sulfate as efficient, green, stable, and reusable catalyst.

Functionalized ionic liquids supported on silica as mild and effective heterogeneous catalysts for dehydration of biomass to furan derivatives

A series of functional ionic liquid supported silica nanoparticles with different acidity (ILs/SiO2) have been prepared by covalent bonds using novel, non-toxic ethanol as solvent. Compared with using toluene or acetonitrile as solvent in traditional prepared method, the process represents a green, environmental friendly route to synthesize supported functional ionic liquid catalysts (SFILCs). These SFILCs, with the benefits of ionic liquid and the advantages of immobilization, were first systematically utilized in biomass dehydration reactions and proved to be efficient heterogeneous catalysts for the preparation of furan derivatives from various carbohydrates. However, the supported dual acidic functional ionic liquid catalyst (3-sulfobutyl-1-(3-propyltriethoxysilane) imidazolium hydrogen sulfate) was found to be more active and selective than other ILs/SiO2 and the conversion of fructose, glucose, xylose, sucrose, cellobiose was up to 99, 96, 94, 76 and 99%. Moreover, the reducing sugar (TRS) yield of microcrystalline cellulose dehydration was up to 77%.

An Efficient Method for the Synthesis of Some New and Known Polyhydroxyl Aromatic Compounds (Trisphenols) under Solvent-free Conditions

A simple, rapid, green, and highly efficient method for the synthesis of substituted trisphenols is described from the reaction of 2,6-bis (methylol) phenols (BMP) and different substituted phenols in the presence of a nanosilica supported dual acidic ionic liquid (NSSDAIL), supported 1-methyl-3-(4-sulfobutyl) imidazolium hydrogen sulfate, as catalyst under solvent-free conditions. This reaction allowed us to prepare some new and known derivatives of substituted trisphenols. This procedure is a clean and environmentally friendly approach to prepare different 2,6-bis(2-hydroxy benzyl) phenol derivatives that offers many advantages, including short reaction times and high yield of the products, use a non corrosive and reusable catalyst and solvent-free conditions.

An efficient, one-pot synthesis of 2-amino-4H-chromenes catalyzed by (α-Fe2O3)-MCM-41-supported dual acidic ionic liquid as a novel and recyclable magnetic nanocatalyst

A novel (α-Fe2O3)-MCM-41-supported dual acidic ionic liquid (DAIL) catalytic system was prepared. This catalyst was characterized by XRD, TEM, SEM, IR spectra and N2 adsorption–desorption measurements, TGA and acid–base titration. 1-Methyl-3-(4-sulfobutyl) imidazolium hydrogen sulfate as the DAIL inside the mesochannels of α-Fe2O3-MCM-41 led to preparation of a new material which was an efficient magnetic heterogeneous nanocatalyst for one-pot three-component synthesis of some new and known 2-amino-4H-chromenes in water medium conditions. This catalyst was more efficient than other reported catalysts for the synthesis of 2-amino-3-cyano-7-hydroxy-4H-chromenes. High product yields, short reaction times, use of non-corrosives, a robust and reusable magnetic nanocatalyst and water as a green solvent are the most important features of the present work.

Nanosilica-supported dual acidic ionic liquid as a heterogeneous and reusable catalyst for the synthesis of flavanones under solvent-free conditions

A nanosilica-supported dual acidic ionic liquid on the basis of 1-methyl-3-(4-sulfobutyl)imidazolium hydrogen sulfate was synthesized and used as an efficient, green, non-corrosive, non-toxic, heterogeneous, and reusable catalyst for the synthesis of some new and known substituted flavanones. The synthesis was done by the condensation of 2'-hydroxyacetophenone with different aldehydes and the subsequent cyclization of the resulting 2'-hydroxychalcone in the presence of the catalyst. High yields of the products, short reaction times, and solvent-free conditions characterize this new method.

Functionalization of MCM-22 by Dual Acidic Ionic Liquid and Its Paraffin Absorption Modulation Properties

A dual acidic ionic liquid 3-sulfobutyl-1-(3-propyltriethoxysilane)imidazolium hydrogen sulfate was synthesized and immobilized on MCM-22 via covalent bonding, which was characterized by FT-IR, TGA, SEM, BET, XPS, and XRD. The modulating of adsorption capacity by novel immobilized ionic liquid was demonstrated by ethane and ethylene. The results indicate that after immobilization, the main structure of the MCM-22 remains unchanged and the acid amount increased. This material displays relatively superior adsorption ability in tuning the ratio of paraffin/olefin (the adsorbed ratio of ethane/ethylene increased over 30%). The immobilized ionic liquid is believed to tune the adsorption capacity resulting in these enhanced results. In addition, this concept could also be applicable to Friedel–Crafts alkylation, catalytic cracking reaction, adsorption separation, or other competitive adsorption reactions.

ChemInform Abstract: Synthesis of Biscoumarin Derivatives Using Poly(4‐vinylpyridine)‐Supported Dual Acidic Ionic Liquid as a Heterogeneous Catalyst.

AbstractThe main advantages of this methodology are high yields, short reaction times, simple work‐up procedure, easy preparation, handling and recycling of the catalyst.

Nanosilica Supported Dual Acidic Ionic Liquid as a Recyclable Catalyst for the Rapid and Green Synthesis of Polycyclic Phenolic Compounds

Generally ionic liquids have gained increasing attention in organic synthesis as catalyst and solvent. However, there are some drawbacks, including the difficulties in the product purification, ionic liquid recycling, and use of excess amounts of the expensive ionic liquid when the ionic liquid is used in the organic reactions. In addition, the high viscosity of ionic liquids can lead to mass transfer limitations in fast chemical reactions. These problems can be overcome by the use of supported ionic liquid phases. In this article, a simple, efficient and green method has been developed for the synthesis of bisphenolic antioxidants by the reaction of 2-tert-butyl-4-methylphenol and aldehydes in the presence of nanosilica supported dual acidic ionic liquid (NSSDAIL) as robust and reusable catalyst under solvent-free conditions. Three different NSSDAILs were synthesized and characterized using SEM, BET, IR, and XRD techniques. High yields of the products, short reaction times, use of a non corrosive, non toxic and reusable catalyst, and use of solvent-free condition are the worthwhile advantages of the current method.

Dual Acidic Ionic Liquid Immobilized on α-Fe2O3–MCM-41 Magnetic Mesoporous Materials as the Hybrid Acidic Nanocatalyst for the Synthesis of Pyrimido[4,5-d]pyrimidine Derivatives

Magnetic α-Fe2O3–MCM-41 mesoporous material functionalized by dual acidic ionic liquid (DAIL) was prepared through a two-step approach as a novel powerful acidic catalyst which provides high ionic media for reactions, by means of post-surface grafting of the mesochannels of α-Fe2O3–MCM-41 materials with 3-sulfobutyl-1-(3-propyltrimethoxysilane)imidazolium hydrogen sulfate as DAIL. Mesoporous MCM-41 was simply packed on the surface of ferric oxide nanoparticles and DAIL was efficiently incorporated into the mesochannels of MCM-41 generating Lewis and Bronsted acidic sites. The catalyst was characterized by FT-IR, X-ray powder diffraction, HRTEM, vibrating sample magnetometer, X-ray energy diffraction spectra, thermogravimetric and differential thermal analyses, and N2 adsorption–desorption measurements. The synthesized hybrid acidic MCM-41 showed good catalytic performance in the one-pot synthesis of pyrimido[4,5-d]pyrimidine derivatives using 6-aminouracil, aldehyde, and urea or thiourea under solvent free conditions. Moreover, it was proved that under this condition, the use of such a hybrid material as a catalyst plays the role of rendering the reactions while neither the α-Fe2O3–MCM-41 nor the 3-methyl-1-(4-sulfonic acid)butylimidazolium hydrogen sulfate were able to promote this reaction.

Synthesis of biscoumarin derivatives using poly(4-vinylpyridine)-supported dual acidic ionic liquid as a heterogeneous catalyst

A supported dual acidic ionic liquid catalyst was easily prepared from its starting materials (namely poly(4-vinylpyridine) and 1,4-butanesultone) and used as a highly efficient heterogeneous catalytic system for the synthesis of biscoumarin derivatives from the reaction of 4-hydroxycoumarin with aliphatic and aromatic aldehydes. The catalyst can be easily recovered and reused without appreciable change in its efficiency.

Poly(4-vinylpyridine)-Supported Dual Acidic Ionic Liquid: A Novel Heterogeneous Catalyst for the Synthesis of β-Acetamido Ketones

A supported dual acidic ionic liquid catalyst was easily prepared from its starting materials and used as an environmentally friendly heterogeneous catalytic system for the synthesis of β-acetamido ketones from the four-component condensation of an aromatic aldehyde with acetophenone, acetyl chloride, and acetonitrile at room temperature. This catalyst was also applied as an efficient catalyst for the synthesis of α-aminophosphonates. The catalyst favorably combines the properties of ionic liquids and advantages of solid supports and is recoverable without loss in its catalytic activity.

Poly(4-vinylpyridine)-supported dual acidic ionic liquid: an environmentally friendly heterogeneous catalyst for the one-pot synthesis of 4,4'-(arylmethylene)bis(3-methyl-1-phenyl-1H-pyrazol-5-ols)

The main aim of this paper was to model the behavior of red soil and black cotton soil along with fly ash mixture to sorption of chromium at different ranges of pH. Visual MINTEQ version 3.0 was used; it was found that the model predicted the behavior accurately and this was compared with an experimental work done earlier. By conducting this simulation study, it was found that surface complexation and reduction played an important role in the sorption process, which gave a new impetus for the reactions taking place at various pH ranges. As most of the landfill leachates have a pH range of 3 to 8, it was concluded that these model-generated data will help landfill designers make informed decisions in dealing with hazardous waste.