A Rapid and Efficient Synthesis of Diaryl Thioureas via Solvent-Free Reaction Using Microwave

A rapid and efficient method for the preparation of diaryl thiourea compounds was reported for the first time. Twelve diaryl thiourea compounds that possessing biological activity have been synthesized in excellent yields (91-97%). The reaction proved to be extremely simple and highly efficient (in 1.5-4.5 min).

Facile One-Pot Synthesis of Novel Hexahydro-2-quinolinecarboxylic Acids under Solvent-Free Reaction Conditions

A simple and fastthree-component synthesis of new and biologically active hexahydro-2-quinolinecarboxylic acid scaf-fold 4 was carried out using cyclocondensation reaction of arylmethylidenepyruvic acids 1, 1,3-cyclohexandiones 2 and ammonium acetate 3 under solvent-free conditions and at room temperature. This protocol has the advantages of facility, easy work-up, high yields, short reaction time and environmentally friendly character.

Synthesis of mordenite by solvent-free method and its application in the dimethyl ether carbonylation reaction

Mordenite with different Si/Al ratios were synthesized by solvent-free method and used for dimethyl ether(DME)carbonylation reaction.The influence of Si/Al ratio in the feedstock on the structure,porosity and acid sites were systematically investigated.The characterization results showed that with the increase of Si/Al ratio in the feedstock,part of silicon species fail to enter the skeleton and the specific surface area and pore volume of the samples decreased.The amount of weak acid and medium strong acid decreased alongside with the increasing Si/Al ratio,and the amount of strong acid slightly increased.The Al atoms preferentially enter the strong acid sites in the 8 member ring(MR)channel during the crystallization process.The high Si/Al ratio sample had more acid sites located in the 8 MR channel,leading to more active sites for carbonylation reaction and higher catalytic performance.Appropriately increasing the Si/Al ratio was beneficial for the improvement of carbonylation reaction activity over the mordenite(MOR)catalyst.

Highly efficient synthesis of β-amino esters via Mannich-type reaction under solvent-free conditions using ZnCl_2 catalyst

β-Amino esters were synthesized via ZnCl2-catalyzed Mannich-type reaction of imines and malonate esters under solvent-free conditions in 6 min. The β-amino ester was converted into the corresponding aspartic acid derivatives.

New observation on a class of old reactions:Chemoselectivity for the solvent-free reaction of aromatic aldehydes with alkylketones catalyzed by a double-component inorganic base system

Solvent-free reactions of aromatic aldehydes with three representative ketones,including acetophenone,acetone and cyclohexanone,have been examined under the catalysis of a low-cost inorganic base system consisting of NaOH and K2CO3.It was found that the chemoselectivity of the reactions is in close relationship with the composition of the reactants and the doublecomponent catalyst.Under the optimized experimental conditions,1,2,3,4,5-pentasubstituted cyclohexanols,α,β-unsaturated ketones and Claisen-Schmidt bicondensation products were obtained in high yields.Two Kostanecki's triketones were separated,The composition and structure were affirmed by X-ray crystallographic analysis.

An Efficient and Solvent-Free Reaction for Synthesis of Bis（indol-3-yl）methanes Catalyzed by Sulfamic Acid

SA （sulfamic acid） catalyzes the reaction of indole with aldehyde and ketone to afford bis（indol-3-yl）methanes in good to excellent yields under solvent-free condition at ambient temperature.

Solvent-Free Manufacturing of Lithium-Ion Battery Electrodes via Cold Plasma

Slurry casting has been used to fabricate lithium-ion battery electrodes for decades,which involves toxic and expensive organic solvents followed by high-cost vacuum drying and electrode calendering.This work presents a new manufacturing method using a nonthermal plasma to create inter-particle binding without using any polymeric binding materials,enabling solvent-free manufacturing electrodes with any electrochemistry of choice.The cold-plasma-coating technique enables fabricating electrodes with thickness(>200 pm),high mass loading(>30 mg cm^(-2)),high peel strength,and the ability to print lithium-ion batteries in an arbitrary geometry.This crosscutting,chemistry agnostic,platform technology would increase energy density,eliminate the use of solvents,vacuum drying,and calendering processes during production,and reduce manufacturing cost for current and future cell designs.Here,lithium iron phosphate and lithium cobalt oxide were used as examples to demonstrate the efficacy of the cold-plasma-coating technique.It is found that the mechanical peel strength of cold-plasma-coating-manufactured lithium iron phosphate is over an order of magnitude higher than that of slurry-casted lithium iron phosphate electrodes.Full cells assembled with a graphite anode and the cold-plasma-coating-lithium iron phosphate cathode offer highly reversible cycling performance with a capacity retention of 81.6%over 500 cycles.For the highly conductive cathode material lithium cobalt oxide,an areal capacity of 4.2 mAh cm^(-2)at 0.2 C is attained.We anticipate that this new,highly scalable manufacturing technique will redefine global lithium-ion battery manufacturing providing significantly reduced plant footprints and material costs.

An upper bound on the steady flow velocity of solvent-free nanofluids

The rheological properties and limited flow velocities of solvent-free nanofluids are crucial for their technologically significant applications.In particular,the flow in a solvent-free nanofluid system is steady only when the flow velocity is lower than a critical value.In this paper,we establish a rigid-flexible dynamic model to investigate the existence of the upper bound on the steady flow velocities for three solvent-free nanofluid systems.Then,the effects of the structural parameters on the upper bound on the steady flow velocities are examined with the proposed structure-preserving method.It is found that each of these solvent-free nanofluid systems has an upper bound on the steady flow velocity,which exhibits distinct dependence on their structural parameters,such as the graft density of branch chains and the size of the cores.In addition,among the three types of solvent-free nanofluids,the magnetic solvent-free nanofluid poses the largest upper bound on the steady flow velocity,demonstrating that it is a better choice when a large flow velocity is required in real applications.

A Solvent-Free Covalent Organic Framework Single-Ion Conductor Based on Ion-Dipole Interaction for All-Solid-State Lithium Organic Batteries

Single-ion conductors based on covalent organic frameworks(COFs)have garnered attention as a potential alternative to currently prevalent inorganic ion conductors owing to their structural uniqueness and chemical versatility.However,the sluggish Li+conduction has hindered their practical applications.Here,we present a class of solvent-free COF single-ion conductors(Li-COF@P)based on weak ion-dipole interaction as opposed to traditional strong ion-ion interaction.The ion(Li+from the COF)-dipole(oxygen from poly(ethylene glycol)diacrylate embedded in the COF pores)interaction in the Li-COF@P promotes ion dissociation and Li+migration via directional ionic channels.Driven by this single-ion transport behavior,the Li-COF@P enables reversible Li plating/stripping on Li-metal electrodes and stable cycling performance(88.3%after 2000 cycles)in organic batteries(Li metal anode||5,5’-dimethyl-2,2’-bis-p-benzoquinone(Me2BBQ)cathode)under ambient operating conditions,highlighting the electrochemical viability of the Li-COF@P for all-solid-state organic batteries.

Heterogeneous Reactions between Starch and AKD under Solvent-free Conditions

Oxidized starch powder and cationic starch solution were reacted with alkyl ketene dimer(AKD) under heterogeneous conditions at 70℃ for 12 h.The AKD molecules reacted with starch hydroxyl groups to form β-keto ester linkages under the above conditions.The reaction products were separated into CHCl_3-soluble and CHCl_3-insoluble fractions.FT-IR spectroscopy,SEM,Xray diffraction,and TG-DTA analyses of the CHCl_3-insoluble fraction indicated that β-keto ester substituents were introduced to hydroxyl groups on the starch surfaces.The results indicated that hydrogen bonds between the starch molecules were disrupted under heterogeneous conditions upon heating.The activity and accessibility of hydroxyl groups were enhanced,as a result of which β-keto ester bonds were produced between AKD and starch.Based on these results,we speculate that the β-keto esters which existed in the sheets sized by AKD emulsions were generated by the reaction between AKD and starch.

Highly mass activity electrocatalysts with ultralow Pt loading on carbon black for hydrogen evolution reaction

Pt-based nanocatalysts offer excellent prospects for various industries.However,the low loading of Pt with excellent performance for efficient and stable nanocatalysts still presents a considerable challenge.In this study,nanocatalysts with ultralow Pt content,excellent performance,and carbon black as support were prepared through in-situ synthesis.These~2-nm particles uniformly and stably dispersed on carbon black because of the strong s-p-d orbital hybridizations between carbon black and Pt,which suppressed the agglomeration of Pt ions.This unique structure is beneficial for the hydrogen evolution reaction.The catalysts exhibited remarkable catalytic activity for hydrogen evolution reaction,exhibiting a potential of 100 mV at 100 mA·cm^(-2),which is comparable to those of commercial Pt/C catalysts.Mass activity(1.61 A/mg)was four times that of a commercial Pt/C catalyst(0.37 A/mg).The ultralow Pt loading(6.84wt%)paves the way for the development of next-generation electrocatalysts.

In（OTf）3-Catalyzed Synthesis of Functionalized 1,5-Benzodiazepines from o-Phenylenediamine and Alkyl Propiolates under Solvent-Free Reaction Conditions

A simple, environmental-friendly, and practical method for the synthesis of benzodiazepine derivatives through a reaction of substituted o-phenylenediamines with alkyl propiolates has been developed. The reactions generated the 1,5-benzodiazepines in good to excellent yields in the presence of catalytic amount of In（OTf）3 under sol- vent-free reaction conditions.

Boosting Oxygen Evolution Reaction Performance on NiFe‑Based Catalysts Through d‑Orbital Hybridization

Anion-exchange membrane water electrolyzers(AEMWEs)for green hydrogen production have received intensive attention due to their feasibility of using earth-abundant NiFe-based catalysts.By introducing a third metal into NiFe-based catalysts to construct asymmetrical M-NiFe units,the d-orbital and electronic structures can be adjusted,which is an important strategy to achieve sufficient oxygen evolution reaction(OER)performance in AEMWEs.Herein,the ternary NiFeM(M:La,Mo)catalysts featured with distinct M-NiFe units and varying d-orbitals are reported in this work.Experimental and theoretical calculation results reveal that the doping of La leads to optimized hybridization between d orbital in NiFeM and 2p in oxygen,resulting in enhanced adsorption strength of oxygen intermediates,and reduced rate-determining step energy barrier,which is responsible for the enhanced OER performance.More critically,the obtained NiFeLa catalyst only requires 1.58 V to reach 1 A cm^(−2) in an anion exchange membrane electrolyzer and demonstrates excellent long-term stability of up to 600 h.

Solvent-free selective oxidation of cyclohexane with molecular oxygen over manganese oxides:Effect of the calcination temperature

The effects of calcination temperature on the physicochemical properties of manganese oxide catalysts prepared by a precipitation method were assessed by X-ray diffraction,N2 adsorption-desorption,X-ray photoelectron spectroscopy,H2 temperature-programmed reduction,O2 temperature-programmed desorption,and thermogravimetry-differential analysis.The catalytic performance of each of these materials during the selective oxidation of cyclohexane with oxygen in a solvent-free system was subsequently examined.It was found that the MnOx-500 catalyst,calcined at 500 °C,consisted of a Mn2O3 phase in addition to Mn5O8 and Mn3O4 phases and possessed a low surface area.Unlike MnOx-500,the MnOx-400 catalyst prepared at 400 °C was composed solely of Mn3O4 and Mn5O8 and had a higher surface area.The pronounced catalytic activity of this latter material for the oxidation of cyclohexene was determined to result from numerous factors,including a higher concentration of surface adsorbed oxygen,greater quantities of the surface Mn4＋ ions that promote oxygen mobility and the extent of O2 adsorption and reducibility on the catalyst.The effects of various reaction conditions on the activity of the MnOx-400 during the oxidation of cyclohexane were also evaluated,such as the reaction temperature,reaction time,and initial oxygen pressure.Following a 4 h reaction at an initial O2 pressure of 0.5 MPa and 140 °C,an 8.0% cyclohexane conversion and 5.0% yield of cyclohexanol and cyclohexanone were achieved over the MnOx-400 catalyst.In contrast,employing MnOx-500 resulted in a 6.1% conversion of cyclohexane and 75% selectivity for cyclohexanol and cyclohexanone.After being recycled through 10 replicate uses,the catalytic activity of the MnOx-400 catalyst was unchanged,demonstrating its good stability.

Oxalic acid catalyzed solvent-free one pot synthesis of coumarins

Oxalic acid was found to be an efficient catalyst for Pechmann condensation, which includes the reaction between phenols and β-keto esters leading to formation of coumarin derivatives. The advantages of present methods are the use of cheap and easy available catalyst, solvent-free reaction conditions, better yields and shorter reaction time.

BF_3·OEt_2 Promoted Solvent-free Synthesis of Benzimidazole Derivatives

Differently substituted benzimidazoles have been synthesized in very good yields in solvent-free conditions from o-phenylenediamine and aldehydes in the presence of BF3·OEt2 as a catalyst. The method is applicable to aromatic, unsaturated and aliphatic aldehydes and to substituted o-phenylenediamines without significant differences.

Silica triflate as an efficient reagent for the solvent-free synthesis of coumarins

Silica triflate, as a new silica-based reagent, can be used for the efficient synthesis of 4-substituted coumarins via a Pechmann reaction under solvent-free reaction conditions. All reactions were performed at 80 ℃ in good to high yields.

An efficient and green preparation of 5-aminophosphonate substituted pyrimidine nucleosides under solvent-free conditions

An environmentally benign and highly efficient one-pot preparation of α-aminophosphonates under solvent-free conditions was developed. By employing this method, 5-aminophosphonate substituted pyrimidine nucleosides were synthesized in good to excellent yields starting from 5-forrnyl-2＇-deoxyuridine, aniline and dimethylphosphite.

Solvent-free synthesis of some ethyl arylglyoxylates

An efficient and convenient approach to synthesize of ethyl arylglyoxylates by solvent-free grinding was described. Eight ethyl arylglyoxylates had been synthesized by this method, this method provided several advantages such as little pollution, high yield, good selectivity, and simple workup procedure, their structures were confirmed by IR, ^1HNMR.

Influences of process parameters on solvent-free toluene oxidation over Au /γ-MnO_2 catalyst

γ-MnO2 nanorobs and Au/γ-MnO2 catalysts were synthesized and characterized by the X-ray powder diffraction XRD the scanning electron microscope SEM and transmission electron microscope TEM . The characterizations show that Au particles are well dispersed on the surface of γ-MnO2 nanorobs with a particle size of about 10 nm.The catalytic performance is evaluated in solvent-free toluene oxidation with oxygen. The influences of several process parameters such as reaction time reaction temperature initial oxygen pressure and catalyst amounts on the catalytic performance are studied.Catalytic results reveal that Au/γ-MnO2 catalyst has a unique selectivity to benzaldehyde and all these factors greatly influence the conversion of toluene and selectivity of bezaldehyde benzoic acid and benzyl benzoate.However these factors have slight influence on the selectivity of benzyl alcohol.