Thermally stable polymers containing 1,3,4-oxadiazole units obtained from Huisgen reaction

Thermally stable polymers containing 1,3,4-oxadiazole units have been synthesized through Huisgen reaction of the aromatic/aliphatic bis-tetrazole compounds with the aromatic/aliphatic bis-acid chlorides in pyridine as solvent.The obtained polymers are insoluble or slightly soluble even in polar aprotic solvents such as DMSO and DMF.Relatively high inherent viscosity values（0.61-1.33 dL/g,in 0.125%H₂SO₄ at 25℃） were observed for these compounds.Thermal analyses of the polymers using DSC and TGA techniques showed that the polymers have improved thermal stabilities.The glass transition temperature has not been observed in the fully aromatic polymers,but the polymers obtained from 5-[6-（1H-tetrazol -5-yl）hexyl]-lH-tetrazole（Ⅳ） showed very clear T_g.A model reaction was also investigated and the resulting bis-1,3,4-oxadiazole compound was characterized by conventional spectroscopy methods.     

One-pot synthesis of 1, 3-thiazolidin-4-one using Bi(SCH2COOH)3 as catalyst

A catalytic multi-component reaction involving aromatic amine,aromatic aldehydes,mercapto acid as substrates and Bi（SCH₂COOH）₃ as catalyst under solvent free conditions,afforded thiazolidin-4-one in good yields.The efficiency of the catalyst was proved with a variety of substrates,ranging from electrondeficient to electron-rich aldehydes.     

Nucleophilic substitution of hydrogen in naphthalene by chloride(Cl~-)in ionic liquids

Nucleophilic aromatic substitution of hydrogen in non-activated aromatic ring,a very rare phenomenon in organic chemistry,is found in ionic liquids containing Cl^- as anion under mild reaction conditions.The reaction may be carried out by the addition of the halogen-bonding adduct（Br₂Cl^-） as nucleophile to aromatic ring carbon atom,leading to the formation of the nucleophilic substitution product.     

KAl（SO4）2·12H2O catalyzed efficient synthesis of 3,4,6-trisubstituted 2-pyridone in water

An efficient green protocol for the preparation 3,4,6-trisubstituted 2-pyridone of employing a condensation reaction of cyanoacetamide and acetylacetone in the presence of KAl（SO₄）₂·12H₂O in water has been described.The present procedure offers advantage such as shorter reaction time,simple workup,and excellent yields.     

Facile one-pot synthesis of pyrido[2,3-d]pyrimidine derivatives over ZrO2 nanoparticles catalyst

An efficient synthesis of hexahydropyrido[2,3-d]pyrimidinetrione derivatives is achieved via tandem Knoevenagel-Michael addition of aromatic aldehydes,methylcyanoacetate and 4（6）-aminouracil in solvent-free conditions in the presence of 10 mol%of ZrO₂ nanoparticles（ZrO₂ NPs） as a heterogenous catalyst.The procedure is formed in high yields,short reaction time and an environmentally friendly specificity.     

Fe（HSO4）3： An efficient,heterogeneous and reusable catalyst for the synthesis of 14-aryl- or alkyl- 14H-dibenzo[a,j]xanthenes

Fe（HSO4）3 has been used as an efficient and recyclable catalyst for the one-pot synthesis of 14-aryl- or alkyl-14Hdibenzo[aj]xanthene derivatives by the reaction of 2-naphtol and aldehydes. Different types of aromatic and aliphatic aldehydes are used in the reaction and in all cases the products were obtained in good to excellent yields.     

Synthesis and characterization of hyperbranched polyurethane-benzyltetrazole

A series of hyperbranched polyurethane-benzyltetrazoles（H-PBTZs） with different linkage structures were synthesized via the polycondensation of hexamethylenediisocyanate as an A₂ type monomer with（4-（1H-tetrazol-5- yl）benzyl）-diethanolamine（TBDEA） as a BB’₂ type monomer in the absence of catalyst at different temperatures.The FTIR, and ¹³C and ¹H-NMR spectroscopy were used to characterize the molecular structures of TBDEA and H-PBTZs as well as the counterpart linear polyurethane-benzyltetrazole（L-PBTZ）.The molecular composition was determined by the reaction selectivity that the isocyanate group reacted with the hydroxyl group in diethanolamine segment or the active hydrogen atom on tetrazole ring.Raising reaction temperature was propitious to the reaction of isocyanate group with the active hydrogen atom on tetrazole ring.The degrees of branching（DB） for H-PBTZs obtained from the ¹H-NMR spectra increased with raising reaction temperature.The wider molecular weight distribution of 1.7-2.9 for H-PBTZs was obtained via GPC analysis.TGA results showed that H-PBTZs had high thermal stability compared with L-PBTZ.     

The novel usage of thiourea nitrate in aryl nitration简

Thiourea nitrate （TN） was easily prepared from thiourea and nitric acid to explore its use as a new nitration reagent, Nitrations of various aromatic compounds utilizing TN in concentrated sulfuric acid were studied, TN could convert aromatic compounds to the corresponding nitrated derivatives with various abnormal yields under mild conditions. The results suggested that the reaction mechanism might be different from those of traditional nitration reagents.     

Sulfonated poly(4-vinylpyridine) heteropolyacid salts:A reusable green solid catalyst for Mannich reaction

Sulfonated poly（4-vinylpyridine） heteropolyacid salts acted as a heterogeneous catalyst to effectively catalyze the one-pot synthesis of β-amino carbonyl compounds via the Mannich reaction between aromatic aldehydes, aromatic ketone, and aromatic amines. In addition, the catalyst could be easily recovered by the filtration and reused six times without significant loss of catalytic activity.     

Rational design of hollow oxygen deficiency-enriched NiFe2O4@N/rGO as bifunctional electrocatalysts for overall water splitting

Bimetallic metal organic framework(MOF)as a precursor to prepare catalysts with bifunctional catalytic activity of oxygen evolution reaction(OER)and hydrogen evolution reaction(HER)attracts more and more attention.Herein,hollow oxygen deficiency-enriched NiFe₂O₄ is synthesized by pyrolytic FeNi bimetallic MOF.The defects of rGO during carbonization can act as nucleation sites for FeNi particles.After nucleation and N doping,the FeNi particles were served as catalysts for the deposition of dissolved carbon in the defects of the N/rGO.These deposited carbon,like a bridge,connect N/rGO and hollow oxygen deficiency-enriched NiFe₂O₄ together,which giving full play to the advantages of N/rGO in fast electron transfer,thereby improving its catalytic activity.The resultant NiFe₂O₄@N/rGO-800 exhibits a low overpotential of 252 mV at 20 mA cm^-2 for OER and 157 mV at 10 mA cm^-2 for HER in 1 M KOH,respectively.When used as bifunctional electrodes for overall water splitting,it also shows low cell voltage of 1.60 V and 1.67 V at 10 and 20 mA cm^-2,respectively.     

Tris（trimethylsilyl） borate as an electrolyte additive for high-voltage lithium-ion batteries using LiNi1/3Mn1/3Co1/3O2 cathode

The influence of tris（trimethylsilyl） borate（TMSB） as an electrolyte additive on lithium ion cells have been studied using Li/Li Co_1/3Ni_1/3Mn_1/3O₂ cells at a higher voltage,4.7 V versus Li/Li⁺.1 wt% TMSB can dramatically reduce the capacity fading that occurs during cycling at room temperature（RT） and elevated temperature（60 °C）.After 150 cycles at 1 C rate（1 C = 278 m Ah/g）,the capacity retention of Li/Li Co_1/3Ni_1/3Mn_1/3O₂ is up to near 72% in the electrolyte with TMSB added,while it is only about 35% in the baseline electrolyte.The electrochemical behaviors,the surface chemistry and structure of Li/Li Co_1/3Ni_1/3Mn_1/3O₂ cathode are characterized with charge/discharge test,linear sweep voltammetry（LSV）,X-ray photoelectron spectroscopy（XPS）,electrochemical impedance spectroscopy（EIS）,thermal gravimetric analyses（TGA）,scanning electron microscope（SEM） and transmission electron microscopy（TEM）.These analysis results reveal that the addition of TMSB is able to protectively modify the electrode CEI film in a manner that suppresses electrolyte decomposition and degradation of electrode surface structure,even though at both a higher voltage of 4.7 V and an elevated temperature of 60 °C.     

Curing kinetics and thermal stability of epoxy blends containing phosphorous-oxirane with aromatic amide-amine as curing agents

This article describes the synthesis of a series of aromatic amide-amines and their potential use as epoxy hardeners. These amines were synthesized by the reaction of L-phenylalanine（PA） with diamines of different structures i.e.1,4- phenylene diamine（PD）,1,5-diamino naphthalene（N）,4,4’-（9-fluorenyllidene）-dianiline（F）,4,4’-diaminodiphenyl sulphide （DS） and 3,4’-oxydianiline（O） in a stoichiometric ratio（1:1）.Structural characterization of synthesized amide-amines was done with the help of elemental analysis and spectroscopic techniques viz.FT-IR,¹H-NMR and ¹³C-NMR.An epoxy blend was prepared by mixing tris（glycidyloxy） phosphine oxide（TGPO） with conventional epoxy i.e.diglycidyl ether of bisphenol-A（DGEBA） in an equivalent ratio of 2:3 to incorporate phosphorous into the main chain.The curing kinetics of the epoxy blend with synthesized aromatic amide-amines was investigated by non-isothermal DSC technique using multiple heating rate method（5,10,15 and 20 K/min.）.The activation energies were determined by fitting the experimental data into Kissinger and Ozawa kinetic models.The activation energies obtained through Ozawa method were slightly higher than those of Kissinger method but were comparable.However,both the energies were found to be dependent on the structure of amines.The thermal stability and weight loss behavior of isothermally cured thermosets were also investigated using thermogravimetric analysis（TGA） in nitrogen atmosphere.All the samples showed improved thermal stability in terms of char yield than using only amines as hardeners.     

[Cp2Ln(m-h1:h2-OC(SR)=CPh2 )]2 的合成和表征

[Cp2Ln（μ-SR）]2 was reacted with Ph2C=C=O to yield ketene mono-insertion products [Cp2Ln（μ-η1：η2-OC（SR）=CPh2）]2 [R=Bn, Ln=Yb （1）, Er （2）, Y （3） and R--Ph, Ln=Yb （4）], indicating that the reactions of organolanthanide thiolates with ketenes are independent of the nature of the thiolate ligand and the ketene as well as the reaction condition. These reactions could provide an efficient method for the synthesis of organolanthanide complexes with the a-thiolate-substituted enolate ligand. All these complexes were characterized by elemental analysis and spectroscopic properties and the structure of complex 1 was determined through X-ray single crystal diffraction analysis.     

β-MnO2 with proton conversion mechanism in rechargeable zinc ion battery

Rechargeable aqueous zinc ion battery(RAZIB)is a promising energy storage system due to its high safety,and high capacity.Among them,manganese oxides with low cost and low toxicity have drawn much attention.However,the under-debate proton reaction mechanism and unsatisfactory electrochemical performance limit their applications.Nanorod b-MnO₂ synthesized by hydrothermal method is used to investigate the reaction mechanism.As cathode materials for RAZIB,the Zn//b-MnO₂ delivers 355 mA h g^-1(based on cathode mass)at0.1 A g^-1,and retain 110 mA h g^-1 after 1000 cycles at 0.2 A g^-1.Different from conventional zinc ion insertion/extraction mechanism,the proton conversion and Mn ion dissolution/deposition mechanism of b-MnO₂ is proposed by analyzing the evolution of phase,structure,morphology,and element of b-MnO₂ electrode,the pH change of electrolyte and the determination of intermediate phase MnO OH.Zinc ion,as a kind of Lewis acid,also provides protons through the formation of ZHS in the proton reaction process.This study of reaction mechanism provides a new perspective for the development of Zn//MnO₂ battery chemistry.     

Ceric ammonium nitrate supported HY-zeolite：An efficient catalyst for the synthesis of 1, 8-dioxo-octahydroxanthenes

Ceric ammonium nitrate （CAN） supported HY-zeolite has been used as an efficient catalyst for the one- pot synthesis of 1,8-dioxo-octahydroxanthenes from the readily available 1,3-diketone and aromatic aldehydes under solvent-free conditions. The present methodology is cost-effective in addition to other advantages like high yields of products in shorter reaction time and simple workup procedure without the use of any injurious solvents.     

水中N-羟基吖啶衍生物的一步合成

N-Hydroxylacridinedione derivatives were synthesized by three-component reaction of aromatic aldehydes, 1,3-dicarbonyl compounds and hydroxylamine hydrochloride using triethylbenzylammonium chloride （TEBA） as the catalysis in water. The reaction has many advantages including good yields, easy to be separated and environmental friendliness.     

Crosslinked Polystyrene Beads Modified with Sulfonyl Groups and Their Application in Aromatic/Aliphatic Hydrocarbons Separation

The separation of aromatic hydrocarbons from aromatic/aliphatic mixtures was investigated with cross- linked polystyrene（CPS） beads modified with sulfonyl groups. Three sulfonating agents, i.e. benzenesulfonyl chlo- ride（BsCl）, 4-toluene sulfonyl chloride（TsC1） and methanesulfonyl chloride（MsC1） were used to prepare sulfonyl CPS beads by Friedel-Crafts reaction. The CPS beads modified with BsC1 exhibited higher sulfonation rate than those modified with MsC1 and TsCI and obtained optimum selectivity in the experiments of toluene/n-heptane separation. Further separation tests with various other aromatic/aliphatic mixtures were carried out at an initial aromatic concen- tration of 13%（mass fraction） with the results showing that the modified beads have preferential selectivity for aro- matic hydrocarbons in all aromatic/aliphatic mixtures, and especially a separation factor of 8.21 and a swelling ratio of 30% for toluene/cyclohexane system. The thermal stability and regeneration test indicate that the used polystyrene beads can be recovered through heat-drying and reused effectively.     

Mn（OAc）2/Schiff base as a new efficient catalyst system for the Henry reaction of nitroalkanes with aldehydes

A series of novel Schiff bases bearing triazole structure were synthesized and characterized by IR and NMR.Mn（OAc）₂/Schiff base efficiently catalyzed Henry reaction of nitroalkanes with aldehydes to produce the corresponding products of β-nitroalcohols, under mild conditions with high yields（up to 99%）.A reaction mechanism is proposed based on the experimental results.     

The role of NiFe2O4 nanoparticle in the anaerobic digestion（AD） of waste activated sludge（WAS）

Anaerobic digestion（AD） is a promising technology for the treatment of waste activated sludge（WAS）with energy recovery. However, the low methane yield and slow methanogenesis limit its broad application. In this study, the NiFe₂O₄ nanoparticles（NPs） were fabricated and applied as a conductive material to enhance the AD via promoting the direct interspecies electron transfer（DIET）. The crystal structure,specific surface area, morphology and elemental composition of the as-pr...     

The efficient synthesis of 14-alkyl or aryl 14H-dibenzo[a,j]xanthenes catalyzed by bismuth(Ⅲ)chloride under solvent-free conditions

An efficient method for the synthesis of 14-alkyl or aryl 14H-dibenzo[a,j]xanthene derivatives by the reaction of β-naphthol,and aldehydes in the presence of a catalytic amount of bismuth（Ⅲ） chloride（BiCl₃） under solvent-free conditions at 110℃is described.Aliphatic and aromatic aldehydes were used in the reaction and in all cases the desired products were synthesized successfully.This reaction was studied under different temperatures;the maximum yield was obtained in a short reaction period at 110℃.The method offers the advantages of high yields,short reaction times,simplicity and easy workup compared to the conventional method of syntheses.