Liquid Catalyst Research Articles

CO2 reduction on the Li–Ga liquid metal surface

Gallium as a solvent liquid metal catalyst is used in an energy efficient, high yield and controlled reaction between lithium and CO2. A liquid metal electrode and the naturally formed surface products are used as a supercapacitor.

Selective conversion of methane to ethane and hydrogen over In/molecular-sieve-3A catalyst

The molecular-sieve-3A material functioned as a good support for the indium liquid metal catalyst for the dehydrogenative conversion of methane (DCM) to ethane, ethylene, and H2 with 100% selectivity at 873 K.

Preparation of a heteropoly acid ionic liquid and its application in the catalytic degradation of bottle-grade PET

A new environmentally friendly process method for catalytically degrading bottle-grade PET by utilizing ionic liquid catalysts.

Kinetic and thermodynamic studies of HMF-ester synthesis using Brønsted–Lewis acidic ionic liquid catalyst

5-HMF to HMF-ester conversion kinetics.

Efficient dimerization of perfluoroolefin with strong nucleophilic ionic liquid catalysts by adjusting the interaction of anions and cations

Ionic liquids, as an efficient nucleophilic catalyst, is used for the first time in the dimerization of perfluoroolefin, and further promotes the greening of fluorochemical reactions.

A multi-walled carbon nanotube-supported acidic ionic liquid catalyst for the conversion of biomass-derived saccharides to 5-hydroxymethylfurfural

Herein, the surface of multi-walled carbon nanotubes (MWCNTs) was functionalized with 3-mercaptopropyltrimethoxysilane followed by anchoring of 1-vinylimidazole on the surface through the thiol–ene click reaction.

Exploring the synthetic potential of a g-C3N4·SO3H ionic liquid catalyst for one-pot synthesis of 1,1-dihomoarylmethane scaffolds via Knoevenagel-Michael reaction.

A highly promising approach for the synthesis of functionalized 1,1-dihomoarylmethane scaffolds (bis-dimedones, bis-cyclohexanediones, bis-pyrazoles, and bis-coumarins) using g-C3N4·SO3H ionic liquid via Knoevenagel-Michael reaction has been developed and the synthesized derivatives were well characterized using spectral studies. The method involved the reaction of C-H activated acids with a range of aromatic aldehydes, in a 2 : 1 ratio catalyzed by a g-C3N4·SO3H ionic liquid catalyst. The use of g-C3N4·SO3H as a catalyst has several benefits, such as low cost, easy preparation, and high stability. It was synthesized from urea powder and chloro-sulfonic acid and was thoroughly characterized using FT-IR, XRD, SEM, and HRTEM. The present work unveils a promising and environmentally friendly method for synthesizing 1,1-dihomoarylmethane scaffolds with high yield, selectivity, and efficiency, using mild reaction conditions, no need for chromatographic separation, and short reaction times. The approach adheres to green chemistry principles and offers a viable alternative to the previously reported methods.

Cholinium-based ionic liquid catalysts for polyethylene terephthalate glycolysis: understanding the role of solvent and a reappraisal of the cation contribution

A combined computational and experimental study has identified a new PET degradation pathway using cholinium-based ionicliquids, leading to a re-evaluation of the cholinium unit's role in catalysis and improved catalyst design.

Polystyrene-supported imidazolium acidic ionic liquids: highly efficient catalysts for the synthesis of bisphenols

Reusable polystyrene-supported ionic liquid catalysts exhibit high catalytic activity for the synthesis of bisphenol compounds. The anions and cations of ionic liquids activate the substrates simultaneously, playing a synergistic catalytic role.

Preparation of functionalised heteropolyacid ionic liquids and their application in catalytic degradation of bottle-grade polyester

This research study is related to an environmentally friendly process method for catalytic degradation of bottle-grade PET by using ionic liquid catalysts.

PolyE-IL Is an Efficient and Recyclable Homogeneous Catalyst for the Synthesis of 5-Hydroxymethyl Furfural in a Green Solvent.

5-Hydroxymethyl furfural (5-HMF) is a potential platform molecule with multidimensional applications and can be produced from biomass-based hexose sugars. In the present article, polyethyleneimine (PEI)-functionalized polymeric Bronsted acid ionic liquid (PolyE-IL) catalyst has been explored for fructose dehydration in the presence of isopropyl alcohol (IPA) as a green and low-boiling-point (LBP) organic solvent. The use of homogeneous PolyE-IL catalyst provides several specific advantages in terms of high yield, conversion, selectivity, ease of catalyst separation, recycle and reuse, and so forth. PEI with various Bronsted acid counterions such as H2SO4, H3PO4, TsOH, TfOH, and TFA provides the corresponding variables of PolyE-IL such as [PEI]+[HSO3]-, [PEI]+[H2PO4]-, [PEI]+[CF3CO2]-, [PEI]+[TfO]-, and [PEI]+[TsO]-, which are tested for fructose dehydration in the presence of IPA. Of the tested catalysts, only PolyE-IL with [HSO4]-, [CF3CO2]-, [TfO]-, and [TsO]- counterions showed the formation of 5-HMF. [PEI]+[HSO4]- showed the maximum yield of 5-HMF (61%) and selectivity (70%) with (87%) fructose conversion. Thus, further process optimization study was conducted to obtain the maximum yield, conversion, and selectivity. The intensified process provides a maximum yield of 5-HMF of 75% with 85% fructose conversion and 90% selectivity. The catalyst recyclability study showed the consistency in 5-HMF yield (75%), conversion (85%), and selectivity (90%) for five consecutive recycle runs. However, the study of reaction kinetics showed the first-order kinetics with an activation energy of 12.4 kJ/mole by using [PEI]+[HSO4]- catalyst. Thus, the use of an easily recyclable and robust catalyst provides an efficient route for production of 5-HMF in the presence of a green solvent.

Novel MCM-41 Supported Dicationic Imidazolium Ionic Liquids Catalyzed Greener and Efficient Regioselective Synthesis of 2-Oxazolidinones from Aziridines and Carbon Dioxide.

A type of MCM-41 supported dicationic imidazolium ionic liquid nanocatalyst has been synthesized and found to be competent for the synthesis of 2-oxazolidinones through the sustainable chemical conversion of CO2 with aziridines. It was shown that the highest efficiency was achieved in the cycloaddition of a series of aziridines and CO2 in the presence of a catalytic amount of the solid catalyst MCM-41@ILLaCl4 under mild conditions. Merits of this meticulously designed protocol are the use of a novel supported ionic liquid catalyst, the easy work-up process, good to excellent yields, a short reaction time, and purification without column chromatography. Overall, the present protocol of synthesizing 2-oxazolidinones under cocatalyst- and solvent-free conditions using MCM-41@ILLaCl4 is promising for industrial applications.

Glycerine esterification with free fatty acids using SBA-15 functionalized catalysts: Effect of hydrophobicity

Mesoporous silica (SBA-15) functionalized with different concentrations of sulfonic groups is used in the esterification of glycerine with fatty acids. This article addresses the effects of temperature, free fatty acids/glycerine ratio and catalyst concentration. It has been shown that high amounts of secondary products may be formed in this reaction system. Accordingly, this work also analyzes the effect of reaction conditions on this yield and presents a comparison with the effect obtained using homogeneous catalysts. Significant amounts of secondary products are also formed with liquid catalysts. The hydrophobic/hydrophilic behavior of the catalysts plays a key role both in the activity and selectivity to the desired products. A catalyst was prepared tuning the hydrophobicity of the surface in order to test this hypothesis, obtaining a higher activity than in the conventional catalyst. These results show the importance of designing catalysts with amphiphilic properties for this system.

Design, synthesis, docking studies and anticancer evaluation of spiro[indoline-3,4′-pyrano[2,3-c]pyrazole] derivatives on MIN-6 cancer cell line

A series of spiro[indoline-3,4′-pyrano[2,3-c]pyrazoles] were synthesized by a one-pot four-component reaction of ethyl acetoacetate, hydrazine hydrate, malononitrile, and isatin catalyzed by new polymer-supported ionic liquid (PSIL) catalyst in an aqueous solution at ambient conditions. Newly synthesized compounds were fully characterized by FT-IR, 1H and 13C NMR, and mass spectrometry. The pharmacokinetic properties were screened and followed by molecular docking on COX-2 to check the in silico potency. Cytotoxicity of 5a-j molecules was evaluated against the Min-6 pancreatic cancer cell line. The 5a-j molecules have been found to have a good drugable profile and good binding affinity with the COX-2 enzyme. In addition, the in vitro cytotoxic potential of the synthesized compounds showed promising inhibition potential against cancer cell lines. The most promising compounds, 5e (IC50 11.33) and 5g (IC50 17.30) show the most remarkable cytotoxic activity as compared to other analogues. The results convey that the designed molecules are promising products for level-up biological evaluation.

Ionic Liquid Supported on Magnetic Graphene Oxide as a Highly Efficient and Stable Catalyst for the Synthesis of Triazolopyrimidines.

A novel sulfonic acid functionalized ionic liquid was prepared by anchoring 1-(propyl-3-sulfonate) vinylimidazolium hydrogen sulfate ([(CH2)3SO3HVIm]HSO4) on Fe3O4@GO. The prepared heterogeneous catalyst was characterized by XRD, FT-IR, EDX, SEM, VSM and TGA techniques. The results show that [(CH2)3SO3HVIm]HSO4 was successfully deposited on the surface of Fe3O4@GO and the prepared ionic liquid catalyst exhibited good thermal stability. The activity of the prepared catalyst was investigated in the synthesis of triazolo[1,5-a]pyrimidine derivatives by a one-pot three-component reaction of active methylene compound (malononitrile or ethyl cyanoacetate), 3-amine-1H-1,2,4-triazole and aryl aldehydes under solvent-free conditions. This catalyst could be rapidly separated by an external magnet and recycled seven times without significant loss of catalytic activity.

Novel Organobimetallic Liquid Catalyst for Enhancing Oil Recovery in Sand-Pack Columns

AbstractThe employing of a self-synthesized organobimetallic catalyst as a viscosity reducing agent to upgrade the heavy oil as well as the mechanisms of enhancing heavy oil recovery are investigated in this study. The components in treated and untreated heavy oil (saturates, aromatics, resins, and asphaltenes or SARA) were assessed, as well as the effects of organobimetallic liquid catalyst (OLC) on viscosity, density, and interfacial tension (IFT) of heavy oil samples were investigated. The results indicate that the OLC-treated heavy oil exhibited reduced viscosity and density. The findings also demonstrate that the presence of the OLC significantly altered the heavy oil's composition and eliminated several contaminants. The effects of OLC treatment on heavy oil recovery were also studied. OLC enhanced the mobility of heavy oil by reducing the IFT of oil brine and increased the recovery factor by 20.36% when compared to untreated heavy oil. These findings will need to be further refined and tested in terms of OLC concentration and other process parameters, but they shed light on a promising initial step toward commercial applications.

Selective hydroxyalkoxylation of epoxidized methyl oleate by an amphiphilic ionic liquid catalyst

AbstractOleic acid is an attractive biobased platform chemical. Precursors for biobased materials can be accessed by epoxidation and subsequent hydroxyalkoxylation of oleic acid. The hydroxyalkoxylation step is conventionally performed with sulfuric acid or a metal catalyst. Due to their high polarity, many ionic liquid catalysts are ineffective for hydroxyalkoxylation of fatty acid derivatives with non‐polar alcohols. In this work, we utilized an amphiphilic ionic liquid catalyst to perform hydroxyalkoxylations of epoxidized methyl oleate. An ionic liquid catalyst based on dimethyl lauryl amine was synthesized and evaluated for this reaction due to its long alkyl group. The amphiphilic nature of the ionic liquid allowed for better miscibility and reactivity compared to other ionic liquids. Several alcohols were used with high yields (≥80%) and selectivity (≥92%), including nonpolar alcohols with longer alkyl chains such as octanol and dodecanol. The high selectivity of these conditions could be advantageous for applications in lubricants, biofuels, or polyol preparation. This work demonstrates a greener alternative to conventional hydroxyalkoxylation catalysts.

Liquid Fluxional Ga Single Atom Catalysts for Efficient Electrochemical CO2Reduction

AbstractPrecise design and tuning of the micro‐atomic structure of single atom catalysts (SACs) can help efficiently adapt complex catalytic systems. Herein, we inventively found that when the active center of the main group element gallium (Ga) is downsized to the atomic level, whose characteristic has significant differences from conventional bulk and rigid Ga catalysts. The Ga SACs with a P, S atomic coordination environment display specific flow properties, showing CO products with FE of ≈92 % at −0.3 V vs. RHE in electrochemical CO2reduction (CO2RR). Theoretical simulations demonstrate that the adaptive dynamic transition of Ga optimizes the adsorption energy of the *COOH intermediate and renews the active sites in time, leading to excellent CO2RR selectivity and stability. This liquid single atom catalysts system with dynamic interfaces lays the foundation for future exploration of synthesis and catalysis.

Liquid Fluxional Ga Single Atom Catalysts for Efficient Electrochemical CO2 Reduction.

Precise design and tuning of the micro-atomic structure of single atom catalysts (SACs) can help efficiently adapt complex catalytic systems. Herein, we inventively found that when the active center of the main group element gallium (Ga) is downsized to the atomic level, whose characteristic has significant differences from conventional bulk and rigid Ga catalysts. The Ga SACs with a P, S atomic coordination environment display specific flow properties, showing CO products with FE of ≈92 % at -0.3 V vs. RHE in electrochemical CO2 reduction (CO2 RR). Theoretical simulations demonstrate that the adaptive dynamic transition of Ga optimizes the adsorption energy of the *COOH intermediate and renews the active sites in time, leading to excellent CO2 RR selectivity and stability. This liquid single atom catalysts system with dynamic interfaces lays the foundation for future exploration of synthesis and catalysis.

Machine learning for the yield prediction of CO2 cyclization reaction catalyzed by the ionic liquids

Ionic liquids are one of the excellent catalysts for the CO2 cycloaddition reaction, which is an effective means to realize CO2 utilization and alleviate environmental problems. However, the design of ionic liquids catalysts has great blindness due to the diversity of their anion and cation structures. Herein, we collected a database of 866 samples for CO2 cyclization with ionic liquids as catalysts and established the yield prediction model with various machine learning regression algorithms. Together with density function theory (DFT) calculated molecular electronic properties and the experimental conditions as the input descriptors, random forest (RF) model has better prediction accuracy than support vector regression (SVR) and multilayer perceptron (MLP) for the whole data. When the dataset was subdivided into different subsets based on substrates and ionic liquids, the prediction accuracy of the model was also improved. For the imidazole subset with no additional solvent or additive added, the RF model achieves good accuracy with the R2 of 0.80 for the test data. Moreover, the shapely additive explanation (SHAP) method was used to interpret the ML models. The strategy of refining the descriptors and dataset used in our work provides guidance for establishing highly reliable machine learning models in the chemistry reactions.