ZrOCl2·8H2O as an efficient and recyclable catalyst for the clean synthesis of xanthenedione derivatives under solvent-free conditions

ZrOCl₂·8H₂O was found to be an efficient and recyclable catalyst for the reaction of aromatic aldehydes with dimedone to afford 1,8-dioxo-1,2,3,4,5,6,7,8-octahydroxanthenes under solvent-free conditions. Short reaction time, excellent yields and simple work-up are the advantages of this procedure. The interaction obtained from XRD studies was shown that the catalyst loses H₂O during the reaction but it did not affect catalytic activity of the catalyst and the catalyst could be reused several times.     

A sulfonic acid functionalized ionic liquid as a homogeneous and recyclable catalyst for the one-pot synthesis of α-aminophosphonates

A sulfonic acid functionalized ionic liquid is used as a Brønsted acid catalyst for the one-pot, three-component synthesis of α-aminophosphonates from aldehydes and ketones at room temperature in water. This homogeneous catalytic procedure is simple and efficient and the catalyst can be reused at least six times without any noticeable decrease in catalytic activity.     

Salicylaldoxime-functionalized poly(ethylene glycol)-grafted dicationic ionic liquid as a water-soluble and recyclable ligand for palladium-catalyzed Mizoroki–Heck reactions in aqueous phase

A water-soluble salicylaldoxime-functionalized poly(ethylene glycol)-grafted dicationic ionic liquid was successfully developed as an efficient ligand for palladium acetate-catalyzed Mizoroki–Heck reactions in water. A series of aryl bromides and terminal olefin were applied to this catalytic system and the corresponding coupling products were produced in high yields. The reusability tests demonstrated that the catalyst system could be recycled for six runs with only a slightly decreased activity.     

Aryloxy ‘biometal’ complexes as efficient catalysts for the synthesis of poly(butylene adipate terephthalate)

A comparative study of catalytic activity of aryloxy complexes of Mg, Zn and Al in the synthesis of poly(butylene adipate terephthalate) demonstrated the preference of Al-based catalyst containing two bulky substituents in ortho-position of phenol ligand in terms of higher values of PBAT MW and lower yields of cyclic diester side product.     

Sol–gel synthesis of NiFe2O4 with PVA matrices and their catalytic activities for one-step hydroxylation of benzene into phenol

Nickel ferrite (NiFe₂O₄) was synthesized using citric acid (CA) as a chelating agent and varying amounts of polyvinyl alcohol (PVA) as powder binder via a combustion process. The influence of PVA/NiFe₂O₄ blend composition on the phase, crystal structure, and morphology has been investigated by X-ray diffraction (XRD), scanning electron microscopy, and Fourier transform infrared spectroscopy, respectively. The probable assignments of the thermal degradation products of PVA/NiFe₂O₄ were studied by complementary thermogravimetric analysis and differential thermal analysis. The PVA/NiFe₂O₄ crystals preferentially oriented along the (311) plane as revealed by XRD, owing to diffusion of α-Fe₂O₃ particles into the lattice matrix where the rate of diffusion increased significantly with the PVA concentration increase from 0.1 to 0.3 mol%. A vibrational doublet at 1,644 and 1,609 cm^?1 for the ≡Fe–O–COOH complex was emitted in the spectra of PVA-impregnated NiFe₂O₄ to assure the attachment of Fe(III) to the chelating agents CA/PVA. Thermal kinetic consideration based on Coats–Redfern and Horowitz–Metzger equations at subsequent decomposition steps of CA/PVA/NiFe₂O₄ illustrated that the values of activation free energy ΔG* increase significantly, indicating the non-spontaneous behavior. The one-step direct hydroxylation of benzene toward phenol has been extensively investigated using hydrogen peroxide as an oxidant.     

Bowl-shaped poly(3,4-ethylenedioxythiophene)/γ-Fe2O3 composites with elecromagnetic function

In this paper, electromagnetic poly(3,4-ethylenedioxythiophene)/γ-Fe2O3 (PEDOT/γ-Fe2O3 ) micro-bowls, 1 2 μm in diameter, were prepared by a simple environment-friendly process. In this method, the aqueous solution of cetyltrimethylammonium bromide (CTAB) instead of any organic solvent was used. FeCl3 acted as a source of Fe Ⅲ for the formation of γ-Fe2O3 and as an oxidant for the polymerization of 3,4-ethylenedioxythiophene (EDOT). The bowl-shaped morphology of PEDOT/γ-Fe2O3 composites was strongly influenced by the concentration of CTAB, FeCl2 , ammonia solution and the reaction temperature. The saturation magnetization of PEDOT/γ-Fe2O3 micro-bowls increased with the increase of FeCl2 concentration and reached 6.20 Am2 /kg at the FeCl2 concentration of 0.30 mol/L. The conductivity of the PEDOT/γ-Fe2O3 composites was in the range of 101 S/cm. The electrical and magnetic sources of PEDOT/γ-Fe2O3 micro-bowls were confirmed by SEM-EDX, TEM, XRD and XPS spectra. And the possible formation mechanism of PEDOT//γ-Fe2O3 was proposed.     

Pd–Co alloy as an efficient recyclable catalyst for the reduction of hazardous 4-nitrophenol

Research on Chemical Intermediates - Palladium–Cobalt (Pd–Co) alloys with different atomic ratios were synthesized successfully by borohydride-assisted chemical reduction method....     

Ambiphilic dual activation role of a task-specific ionic liquid: 2-hydroxyethylammonium formate as a recyclable promoter and medium for the green synthesis of β-nitrostyrenes

A cost-effective task-specific ionic liquid, 2-hydroxyethylammonium formate, efficiently promotes the condensation of nitroalkanes with various aldehydes to produce β-nitrostyrenes in high to excellent yields at room temperature. This reaction does not involve any hazardous organic solvent and toxic catalyst. The ionic liquid is recovered and recycled for subsequent reactions. In addition, a novel mechanism has been proposed invoking ambiphilic dual activation influence of the ionic liquid.     

Dissolution of zinc oxide in a protic ionic liquid with the 1-methylimidazolium cation and electrodeposition of zinc from ZnO/ionic liquid and ZnO/ionic liquid–water mixtures

We show that zinc oxide can be dissolved in the protic ionic liquid 1-methylimidazolium trifluoromethylsulfonate, [MIm]TfO at quite a high concentration (~ 2.5 mol/L). FTIR and Raman spectra revealed the association of zinc ions with 1-methylimidazole. The ZnO/[MIm]TfO solutions and their mixtures with water were employed as electrolytes for the electrodeposition of zinc. High current density electrodeposition of zinc can be achieved in the employed electrolytes. Spongy-like zinc structures with a high porosity were obtained in ZnO/[MIm]TfO and the formation of Au_1.2Zn_8.8 alloy was observed. Compact and hexagonal zinc deposits were found in the presence of water. The present results show the potential of ionic liquids as electrolytes for rechargeable zinc–air batteries.     

Prediction of liquid–liquid equilibrium for ternary systems containing ionic liquids with the tetrafluoroborate anion using ASOG

Liquid–liquid equilibrium (LLE) data for different systems involving ionic liquids are essential for design, optimization and operation of separation processes, such as recovery of valuable products and remotion of polluting agents in effluents. In this work, the ASOG model for the activity coefficient is used to predict LLE data for 32 ternary systems at 101.3 kPa and several temperatures; all the systems are formed by ionic liquids including the tetrafluoroborate anion plus alkanes, alkenes, cycloalkanes, alkanols, ketones, carboxylic acids, esters and aromatics. New group interaction parameters were determined by using a modified Simplex method, minimizing a composition-based objective function. The results, in terms of mean deviation between the experimental and calculated compositions, are satisfactory, with rms deviations of about 4%.     

Choline chloride·2ZnCl2 ionic liquid: an efficient and reusable catalyst for the solvent free Kabachnik–Fields reaction

The choline based Zn containing deep eutectic mixture was applied as an efficient and eco-friendly ionic liquid catalyst for the one pot three-component synthesis of α-aminophosphonates under solvent-free condition at room temperature. The reactions were completed in short times and products were obtained in good to excellent yields.     

N-methyl-2-pyrrolidonium-based Brönsted-Lewis acidic ionic liquids as catalysts for the hydrolysis of cellulose

We experimentally studied the catalytic performances of a series of Br?nsted-Lewis acidic N-methyl-2-pyrrolidonium metal chlorides([Hnmp]Cl/MCl_x, where M=Fe, Zn, Al, or Cu) for the hydrolysis of microcrystalline cellulose(MCC) and cotton to produce reducing sugar. A variety of factors, such as temperature, time, ionic liquid(IL) species, IL dosage, and the concentration of the metal chloride were investigated. [Hnmp]Cl/FeCl_3 presented the best hydrolysis performance, affording a 98.8% yield of total reducing sugar from MCC(1 h, 100 °C, 0.1 g MCC, 0.2 g acidic IL, 2.0 g [Bmim]Cl as solvent), which is better than or comparable to results previously obtained with other –SO_3H functionalized acidic ILs. The hydrolysis performances of [Hnmp]Cl/MClx were rationalized using density functional theory calculations, which indicated that interactions between the metal chlorides and the cellulose, including charge-transfer interactions are important in the hydrolysis of cellulose and degradation of glucose. This work shows that Br?nsted-Lewis acidic ILs are potential catalysts for the hydrolysis of cellulose to produce sugar.     

Ruthenium carboxylate complexes as easily prepared and efficient catalysts for the synthesis of β-oxopropyl esters

The easily prepared complex cis-[Ru(κ²-O₂CMe)₂(PPh₃)₂] is an effective catalyst for the addition of carboxylic acids to propargyl alcohols to afford β-oxopropyl esters. The reaction is tolerant to a range of functional groups on the propargyl alcohol and is effective in the case of the steroid ethisterone. An investigation into the ruthenium-containing products from the reaction involving benzoic acid revealed that rapid exchange between coordinated acetate and benzoate ligands occurs. The synthesis of crystallographically characterised cis-[Ru(κ²-O₂CPh)₂(PPh₃)₂] was developed. This benzoate-substituted complex was shown to react with HCCPh and HCCC(OH)PhH to give [Ru(κ²-O₂CPh)(κ¹-O₂CPh)(CCPhH)(PPh₃)₂] and [Ru(κ²-O₂CPh)(κ¹-O₂CPh)(CCC{OH}PhH)(PPh₃)₂] respectively. Reaction of cis-[Ru(κ²-O₂CPh)₂(PPh₃)₂] with CO affords [Ru(κ²-O₂CPh)(κ¹-O₂CPh)(CO)(PPh₃)₂] or [Ru(κ²-O₂CPh)₂(CO)₂(PPh₃)₂] depending on the conditions employed. Related carbonyl compounds are thought to be the ruthenium-containing products from the catalytic reactions and [Ru(κ²-O₂CMe)(κ¹-O₂CMe)(CO)(PPh₃)₂] was also shown to be a competent catalyst.     

NiCl2·6H2O as recyclable heterogeneous catalyst for N-arylation of amines and NH-heterocycles under microwave exposure

NiCl₂·6H₂O has been proven to be an effective catalyst for the coupling of amines with aryl iodides without ligand under solvent-free conditions employing microwave irradiation. Reactions cleanly result in coupled products in a short reaction time. The catalyst, being heterogeneous, is recovered by filtration and is recyclable.     

(±)-Camphor-10-sulfonic acid as recyclable and efficient catalyst for the synthesis of some novel coumarin derivatives

A highly competent-diversity oriented synthesis of coumarin core derivatives using a Knoevenagel condensation followed by Michael addition and subsequent cyclization in the presence of (±)-camphor-10-sulfonic acid in a water/ethanol (1:1) solvent system is depicted. Furthermore, easy workup procedures with good yield, rapid reactions with high atom economy, and catalyst recyclability are the fascinating features of the procedure.     

Matrix solid-phase dispersion coupled with magnetic ionic liquid dispersive liquid–liquid microextraction for the determination of triazine herbicides in oilseeds

A novel method was developed for the determination of six triazine herbicides from oilseeds by matrix solid-phase dispersion combined with magnetic ionic liquid dispersive liquid–liquid microextraction (MSPD-MIL-DLLME), followed by ultrafast liquid chromatography with ultraviolet detection (UFLC-UV). The MIL, 1-butyl-3-methylimidazolium tetrachloroferrate ([C₄mim][FeCl₄]), was used as the microextraction solvent to simplify the extraction procedure by magnetic separation. The effects of several important experimental parameters, including type of dispersant, ratio of sample to dispersant, type and volume of collected elution solvent, type and volume of MIL, were investigated. Using the present method, UFLC-UV gave the limits of detection (LODs) of 1.20–2.72 ng g⁻¹ and the limits of quantification (LOQs) of 3.99–9.06 ng g⁻¹ for triazine herbicides. The recoveries were ranged from 82.9 to 113.7% and the relative standard deviations (RSDs) were equal or lower than 7.7%. The present method is easy-to-use and effective for extraction of triazine herbicides from oilseeds and shows the potentials of practical applications in the treatment of the fatty solid samples.     

Heterogeneous bimetallic Au–Co nanoparticles as new efficient catalysts for the three-component coupling reactions of amines,alkynes and CH2Cl2

Research on Chemical Intermediates - Propargylamines are key intermediates for the synthesis of many biologically active molecules. A new synthesis of propargylamines via a three component-coupling...