Selective Synthesis of 5-Substituted N -Aryloxazolidinones by Cycloaddition Reaction of Epoxides with Arylcarbamates Catalyzed by the Ionic Liquid BmimOAc

Switchable synthesis of cyclic carbamates by carbon dioxide fixation at atmospheric pressure

The base-promoted switchable synthesis of five- and six-membered cyclic carbamates using atmospheric pressure carbon dioxide as the C1 source was developed. The chemoselectivity of products was simply controlled by changing bases and solvents. The reaction proceeds effectively under mild conditions, affording valuable cyclic carbamates. Experimental results and DFT studies revealed the reaction mechanism.

Fast Track to Acetate-Based Ionic Liquids: Preparation, Properties and Application in Energy and Petrochemical Fields

Acetate-based ionic liquids (AcILs), as a kind of typical carboxylate-based ILs, display excellent structure tunability, non-volatility, good solubility to biomass, and favorable adsorption capacity, etc. These unique characteristics of AcILs make them important candidates for a range of applications in the field of energy and in the petrochemical industry. This paper intends to provide a comprehensive overview of recent advances in AcILs, including pure AcILs, AcIL-based multi-solvents, and AcIL-based composites, etc. Preparation methods, with one- and two-step synthesis, are reviewed. The relationship between properties and temperature is discussed, and some physical and thermodynamic properties of different AcILs are summarized and further calculated. The applications of AcILs in the fields of biomass processing, organic synthesis, separation, electrochemistry, and other fields are reviewed based on their prominent properties. Thereinto, the dual functions of AcILs as solvents and activators for biomass dissolution are discussed, and the roles of AcILs as catalysts and reaction mediums in clean organic synthesis are highlighted. Meanwhile, the reaction mechanisms of AcILs with acid gases are posed by means of molecular simulation and experimental characterization. Moreover, AcILs as electrolytes for zinc batteries, supercapacitors, and electrodeposition are particularly introduced. Finally, the future research challenges and prospects of AcILs are presented.

Poly(ionic liquid)s with superior swelling and enrichment properties in solvents

The molar swelling ratio and enrichment factor of poly(ionic liquid)s were linearly positively correlated with the Hansen solubility parameter of the solvent and the difference between the Hansen solubility parameters of mixed solvents, respectively.

A Phosphonium Ylide as a Ligand for [3 + 2] Coupling Reactions of Epoxides with Heterocumulenes under Mild Conditions

The potential of carbonyl-stabilized phosphonium ylides as ligands for novel catalysis was explored. We found that the combination of phosphonium ylides and metal halide salts efficiently catalyzed the reaction of epoxides with carbon dioxide under mild conditions. Five-membered cyclic carbonates, including disubstituted cyclic carbonates, were obtained in good yields with the use of 1 atm of carbon dioxide at 35 °C. Terminal epoxides could be converted to N-aryl oxazolidinones in the reaction with isocyanates under a similar catalytic system.

Mechanistic Studies of CO2 Cycloaddition Reaction Catalyzed by Amine-Functionalized Ionic Liquids

The homogeneous cycloaddition reaction of CO₂ and epichlorohydrin catalyzed by amine-functionalized ionic liquid (AFIL) to yield cyclic carbonate is reported in this study. The AFIL has the dual function of ionic liquid and organic base. The experimental study indicates that AFIL can efficiently catalyze the conversion of CO₂ and epichlorohydrin to the product 3-chloro-1,2-propylene. The mechanistic study based on DFT calculations reveals that the imidazolium ring in AFIL primarily catalyzes the ring-opening reaction of epichlorohydrin, while the protonated amine group is responsible for stabilizing the Br⁻ anion in the nucleophilic attack. This study provides a deep insight into the catalytic roles of AFIL and also inspires us to design efficient dual function catalysts for CO₂ utilization.

Metal-Organic Framework MIL-101-NH2-Supported Acetate-Based Butylimidazolium Ionic Liquid as a Highly Efficient Heterogeneous Catalyst for the Synthesis of 3-Aryl-2-oxazolidinones

A novel heterogeneous catalyst, the ionic liquid (IL) of 1-butyl-3-methylimidazolium acetate (BmimOAc) immobilized on MIL-101-NH₂, denoted as IL(OAc^-)-MIL-101-NH₂, was prepared by the "ship-in-a-bottle" strategy. The IL of BmimOAc was prepared in the MIL-101-NH₂ nanocages primordially, in which the condensation product of MIL-101-NH₂'s amine group with 1,1'-carbonyldiimidazole (CDI) reacted with 1-bromo butane, and then the intermediate exchanged with potassium acetate. The structure and physicochemical properties of IL(OAc^-)-MIL-101-NH₂ were characterized by powder X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, DRS UV-vis, nitrogen adsorption-desorption, and elemental analysis. The results indicated that BmimOAc was anchored in the MIL-101-NH₂ skeleton via the acylamino group and confined in the nanocages in the form of a single molecule. The composite material of IL(OAc^-)-MIL-101-NH₂ exhibited excellent catalytic activity and catalytically synthesized 3-aryl-2-oxazolone in an excellent yield of 92%. It can be reused up to six times without noteworthy loss of its activity and demonstrated distinct size-selective property for substrates. It was conjectured that the diffusion kinetics of reactants could be controlled by the aperture size of the metal-organic framework support.

4-Hydroxymethyl-substituted oxazolidinone synthesis by tetraarylphosphonium salt-catalyzed reactions of glycidols with isocyanates

A tetraarylphosphonium catalyst enables efficient coupling reactions between glycidols and isocyanates to afford 4-hydroxymethyl-substituted oxazolidinones.

Bifunctional organocatalysts for the conversion of CO2, epoxides and aryl amines to 3-aryl-2-oxazolidinones

A route to synthesize 3-aryl-2-oxazolidinones is developed, which is achieved through a three component reaction between CO₂, aryl amines, and epoxides with a binary organocatalytic system composed of organocatalysts and DBU (1,8-diazabicyclo[5.4.0]undec-7-ene).

Tetraarylphosphonium Salt-Catalyzed Synthesis of Oxazolidinones from Isocyanates and Epoxides

Preparation of a range of oxazolidinones, including enantioenriched N-aryl-substituted oxazolidinones, in which tetraarylphosphonium salts (TAPS) catalyze the [3 + 2] coupling reaction of isocyanates and epoxides effectively, is described. The key finding is a Brønsted acid/halide ion bifunctional catalyst that can accelerate epoxide ring opening with high regioselectivity. Mechanistic studies disclosed that the ylide generated from TAPS, along with the formation of halohydrins, plays a crucial role in the reaction with isocyanates.