A simple and effcient approach to one-pot synthesis of mono- and bis-N-aryl-3-aminodihydropyrrol-2-one-4-carboxylates catalyzed by InCl3简

An efficient and straightforward procedure has been developed for the synthesis of highly substituted mono- and bis-N-aryl-3-aminodihydropyrrol-2-one-4-carboxylates via a one-pot, four-component domino reaction of amines, dialkyl acetylenedicarboxylates and formaldehyde in the presence of InCl3 （20 mol%） in MeOH at ambient temperature. The salient advantages of this method are mild reaction conditions, environmentally benign, high to excellent yields, shorter reaction times, easy operation and no column chromatographic separation.     

EuBO3的低温水热合成及光谱可调性质研究

采用低温水热法合成了稀土硼酸盐EuBO3的纯相样品.利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、X射线光电子能谱仪(XPS)和荧光光谱仪(PL)对样品的结构、形貌、价态及发光性质进行了研究.结果表明,该样品属六方晶系,在不同的矿化剂和碱度下呈现不同的自组装形貌.当以NaOH或NH3.H2O为矿化剂时,该样品分别沿着(100)和(002)晶面生长.因为Eu离子以混合价态形式存在,样品表现出光谱可调性,当激发波长为270～360 nm时,样品荧光由红色转为橙色,经粉紫光变为蓝光.     

PEG-SO3H as an efficient and reusable catalyst for chemoselective synthesis of 1,1-diacetates

An efficient and convenient procedure of the synthesis of 1,1-diacetates from aromatic aldehydes and acetic anhydride under mild and solvent-free conditions at room temperature,in the presence of PEG-SO₃H is reported.PEG-SO₃H acts as a catalyst and can be recovered and reused eight times without apparent loss of its catalytic activity.     

YBO3:Eu荧光粉的水热法制备及形貌控制

用水热法在低于300℃成功地制备出具有不同形貌的YBO3:Eu3+荧光粉,其反应温度比固相反应了约800℃.研究了初始原料、pH值、反应温度、反应溶剂和催化剂等条件对目的产物形貌及粒度的,得到了具有Vaterite结构、粒度分布均匀的球形荧光粉的最佳合成工艺.在254nm激发下,水热法的球形Y0.95Eu0.05BO3荧光粉最强发射峰位于598nm处,属于Eu3+的5D0→7F1的跃迁,是固相反应所品的1.5倍.这些结果表明,在PDP和荧光灯等显示和照明用荧光粉的制备中水热法具有潜在的应用.     

电池正极材料Li3V2(PO4)3/C的水热合成和性能

以LiOH·H2O, NH4VO3, NH4H2PO4 和麦芽糖等为原料, 采用水热法合成了碳包覆的磷酸钒锂化合物, 考察了碳含量对材料电化学性能的影响. 利用XRD, TEM, SEM和恒流充放电测试等手段对产物的结构、 形貌和电化学性能进行表征. 结果表明, 在650℃煅烧的样品为单一纯相的单斜晶体结构. 晶体颗粒分布为100~300 nm, 粒度分散均匀, 分散性良好, 无团聚现象, 且在颗粒表面包覆了一层无定形碳, 这有利于改善材料的导电率. 含碳量为10.23%的样品, 在倍率1.0C的电流密度下, 在3.0~4.3 V电压范围内, 样品的首次放电比容量高达118.8 mA·h/g, 循环15圈后放电比容量为115.1 mA·h/g, 容量保持率为96.88%.     

Fe(OH)2悬浮液在EDTA作用下氧气氧化生成δ-FeOOH的机理研究

At room temperature and in the presence of trace EDTA, the formation of δ-FeOOH was studied by the rapid oxidation of Fe(OH)2 suspension with O2. The structural and morphological changes were characterized by various techniques such as XRD, FTIR and TEM. γ-FeOOH and (δ-FeOOH) formed simutaneously in the early period of oxidation. But as the rate of mass transfer was in equilibrium, trace (γ-FeOOH) vanished gradually. Accordingly, pure phase δ-FeOOH was obtained. At the same time, critical amount ratio K of EDTA to Fe2+ was verified. The experiments show that the reactivity, rate of the oxidizing agent and pH of the initial medium were important factors for the formation of pure phase (δ-FeOOH). Under the auxiliary effect of EDTA, the reactivity of O2 was nearly improved to that of H2O2. And the process of the oxidation that Fe(OH)2 suspension was oxidized by O2 under that condition was discussed.     

复合多铁材料NiFe2O4/BaTiO3的制备及性能

采用溶胶-凝胶与固相反应相结合的方法制备了xNiFe2O4/(1-x)BaTiO3(x=0.1,0.2,0.3,0.4,0.5,0.6)系列复合多铁材料.X射线衍射(XRD)结果表明,复合材料中只含有钙钛矿结构的BaTiO3和尖晶石结构的NiFe2O4,说明共烧过程中两者未发生明显的化学反应,铁电相与铁磁相共存.扫描电子显微镜(SEM)观测结果表明材料内部是异质结构的,高分辨透射电子显微镜(HRTEM)观测结果进一步说明了NiFe2 O4和BaTiO3共存,并且在两种物质的接触处能够看到清晰的界面.这种由BaTiO3和NiFe2 O4组成的复合材料对外同时表现出铁电性和铁磁性.电滞回线结果表明,该复合材料具有铁电性,但存在着一定的漏电.介电频谱表明材料的介电常数随着频率的升高而下降,在低频下达到定值,并且铁磁相的含量对材料的介电性有影响.磁性能测试结果表明材料的磁性源于NiFe2O4,并且磁性随着NiFe2O4含量的增加而增强.     

One-pot synthesis of selenocarbamates from isocyanates and diselenides using the Zn/AlCl3 system

Several N-alkyl/aryl-Se-alkyl/(aryl)selenocarbamates were prepared from various isocyanates and diselenides by reductive cleavage of Se-Se bond with the Zn/AlCl3 system in dry acetonitrile at 80℃.     

TiO2/LaFeO3微纳米纤维的可控制备及光催化性能简

利用静电纺丝技术及水热合成法制备了TiO2/LaFeO3异质结构. 采用场发射扫描电子显微镜(FE-SEM),X射线衍射(XRD),傅里叶变换红外(FTIR)光谱和紫外-可见漫反射光谱(UV-Vis)等手段对TiO2/LaFeO3微纳米纤维的结构和表面形态进行表征. 通过亚甲基蓝(MB)光降解反应研究了其光催化性能. 结果表明,不完全碳化TiO2纤维表面的缺陷位点是LaFeO3纳米粒子的有利生长点. TiO2/LaFeO3异质结材料的带隙明显窄于TiO2,光催化活性得到提高;经140 min紫外光照射后,TiO2/LaFeO3异质结催化剂对MB的降解率为65.34%,分析和探讨了其光催化机理.     

Ag修饰的Fe_3O_4/TiO_2复合磁性纳米纤维的制备及光催化性能

通过静电纺丝法制备了含有Fe3O4纳米粒子的TiO2纳米纤维,采用水热法对该纤维表面进行纳米Ag修饰,制备出具有较强磁性和较好光催化性能的复合纤维.采用X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)和紫外-可见光谱(UV-Vis)等对样品的结构和形貌进行表征,并以罗丹明B(Rh B)水溶液降解为模型反应,考察样品在紫外光照射下的光催化性能.结果表明,所制备的TiO2为锐钛矿结构,Fe3O4纳米粒子均匀分布在TiO2纤维中,Ag纳米颗粒比较均匀地分散在磁性TiO2纤维表面.经过纳米Ag修饰后,材料的光吸收能力大为增强,吸收带红移并扩展到可见光区.在紫外光照射40 min后,合成样品对Rh B的降解率达到99.5%.此外,Fe3O4纳米粒子的存在使该材料具有较强的磁性,可通过外加磁场将其分离回收.     

Synergetic effect of FeVO4 and α-Fe2O3 in Fe-V-O catalysts for liquid phase oxidation of toluene to benzaldehyde

Synergistic effect of FeVO₄ withα-Fe₂O₃ was found in Fe-V-O catalyst,which was responsible for the high apparent formation rate（A.F.R.） of benzaldehyde in liquid phase oxidation of toluene by hydrogen peroxide.The synergistic effect might create VO_πspecies as active sites;moreover,it improved the reducibility and the reactivity of Fe-V-O catalyst.In order to gain the high A.F.R. of benzaldehyde,the catalyst should have the moderate reducibihty.     

The SBA-15/SO3H nanoreactor as a highly efficient and reusable catalyst for diketene-based, four-component synthesis of polyhydroquinolines and dihydropyridines under neat conditions

An efficient diketene ring-opening synthesis of polyhydroquinoline derivatives using SBA-15 sulfonic acid modified mesoporous substrates a green and reusable catalyst in a single-pot four-component coupling reaction of diketene,alcohol,enamine,and aldehydes is reported.Dihydropyridine derivatives based on neat adduct of diketene,alcohols and aldehydes using SBA-15/SO₃H nanoreactor as catalyst via a four-component reactions are also synthesized.The advantages of the present method include the use of a small amount catalyst,simple procedure with an easy filterable work-up,waste-free,green and direct synthetic method with an excellent yield of products with efficient use of catalyst and a short reaction time.     

Design, synthesis and preliminary biological evaluation of brain targeting L-ascorbic acid prodrugs of ibuprofen

L-Ascorbic acid（AA,vitamin C） exhibits a high concentration in the brain.The transportation of AA in brain is mainly mediated by the glucose transporter 1（GLUT₁） and the Na⁺-dependent vitamin C transporter SVCT₂.While L-ascorbic acid C6-O conjugation has been investigated as a tool to enhance brain drug delivery,C5-O conjugation and C5-O & C6-O conjugation as brain targeting tools have not been reported.In this letter,ibuprofen was linked directly to C5-O,C6-O and C5-O & C6-O positions of L-ascorbic acid with eater bonds,providing prodrug 1,2 and 3,respectively,to improve their targeting abilities in the brain.Prodrug 1,2 and 3 were synthesized in facile ways with good yields.And the preliminary evaluation in vivo illustrated that prodrug 2 had a better targeting ability than prodrug 1. Moreover,prodrug 3,whose C5-O & C6-O positions were both modified,had good targeting ability for brain which will provide an important evidence for our further study on C5-0- & C6-0- di-derivatives of L-ascorbic acid.     

改进的低温固相法制备钙钛矿型KTaO3

采用改进的固相法, 以K2CO3和氢氧化钽为原料, 通过添加KF, 在相对低温下制备了单一钙钛矿结构的KTaO3. KF的加入抑制了烧绿石相的生成, 通过水洗可脱除KF. 使用X射线衍射仪(XRD), 扫描电子显微镜(SEM)和紫外-可见(UV-Vis)漫散射光谱仪对不同温度下制备的产物进行了表征. 结果表明, 各个温度下制备的产物均是由粒径在10~30 nm范围内的粒子聚集成的大颗粒; 500, 600和800℃制备的产物带隙分别为3.68, 3.63和3.54 eV. 进一步考察其它碱金属卤化物对产物结构的影响发现, LiF, NaF和KF的作用相同; 当添加碱金属氯化物时, 主要产物分别是钽酸锂、 钽酸钠和烧绿石结构的钽酸钾.     

Catalytic activity of TiO2 nanoparticles in the synthesis of some 2,3-disubstituted dihydroquinazolin-4（1H）-ones

Green chemistry is playing an important role for synthesizing organic compounds, due to its eco-friendly nature and low cost. In green chemistry, metal nanoparticles exhibited some useful physical and chemical properties （catalytic activity）. Due to its diverse properties, nanoparticles can be utilized as a catalyst in various organic reactions. Recent research has been directed towards the utilization of eco- friendly and bio-friendly plant materials in nanoparticles synthesis. In our present work, TiO2 nanoparticles （TiO2 NPs） were synthesized using Annona squamosa peel extract and their catalytic applications were studied on the 2,3-disubstituted dihydroquinazolin-4（l1H）-one synthesis. Synthesized compounds were confirmed using FT-IR.1H NMR, 13C NMR and GC-MS analyses.     

(1S,2S)-DPEN修饰的Ir/Al2O3催化苯乙酮及其衍生物的不对称加氢反应$

在碱性条件下制备了三氧化二铝负载的铱(Ir/γ-Al2O3)催化剂,并用于苯乙酮及其衍生物的不对称催化加氢反应.考察了不同的碱、碱浓度、手性二胺(1S,2S)-1,2-二苯基乙二胺[(1S,2S)-DPEN]浓度、反应温度和反应压力对催化剂及反应的影响.结果显示,在优化反应条件下,该催化剂表现出较高的催化活性和良好的对映选择性,其中异丁酰苯不对称催化加氢反应的对映选择性达到了80.3%.该催化剂不需要使用任何稳定剂,制备方法简单,催化性能稳定,通过简单的离心分离即可循环使用.     

Co3O4纳米片的制备及对H2O2电还原反应的催化性能简

通过恒电势电沉积和加热处理在泡沫镍基体上制备了Co3O4纳米片. 利用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线衍射(XRD)、傅里叶变换红外光谱(FTIR)和X射线光电子能谱(XPS)等手段对纳米片的形貌和结构进行了表征. 采用线性伏安扫描和计时电流技术研究了Co3O4纳米片电极对H2O2的电还原性能. 结果表明,在3.0 mol/L KOH 和 0.4 mol/L H2O2溶液中,当电压为-0.4 V(vs. Ag/AgCl)时,线性伏安扫描电流密度达到-0.386 A/cm2,在1000 s 测试时间内,计时电流密度衰减很小,表明Co3O4纳米片电极对H2O2具有很高的活性和稳定性.     

Novel ZnO-Al2O3 composite particles as sorbent for low temperature H2S removal

ZnO-Al₂O₃ composite particles composed of ZnO nanosheets（thickness of 40-80 nm） on alumina particles were prepared by heterogeneous precipitation method using bayerite seed particles.The asprepared composite particles were characterized in terms of crystal structure,morphology,surface area and pore volume.The composite particles were used as sorbent for H₂S adsorption at low temperature, and were compared with pure ZnO sorbent.The composite sorbent showed a greater sulfur adsorption capacity（0.052 g/g） than pure form of ZnO（0.028 g/g）.This significant improvement was mainly attributed to higher surface area,more pore volume and unique morphology in nanoscale,which were also obtained by low cost presented method in this work for synthesis of ZnO sorbent supported on alumina particles.     

A new and convenient synthesis of phendiones oxidated by KBrO3/H2SO4 at room temperature

<正>A new method is described to synthesize phendione derivatives from 1,10-phenanthrolines using potassium bromate and 60% sulfuric acid as oxidant,which was easily applicable to scale-up.The reaction conditions are mild and the yields are excellent.The target compounds have been characterized by ~1H NMR,and IR.     

γ-Fe_2O_3:A magnetic separable catalyst for synthesis of 5-substituted 1H-tetrazoles from nitriles and sodium azide

<正>An efficient route for the synthesis of 5-substituted 1H-tetrazole via[2+3]cycloaddition of nitriles and sodium azide is reported usingγ-Fe_2O_3 nanoparticles as a magnetic separable catalyst.Under optimized conditions,the moderate to good yields(71-95%) can be obtained.The catalyst can be easily separated by a magnet and reused for several circles.