首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 796 毫秒
1.
A new method for synthesis of 3-azido-3-deoxyxylofuranoside was described. D-ribose was methylated, then treated with methanesulfonyl chloride to give Ⅱ.Ⅱ was selectively replaced by benzoate at the 5-position to give Ⅲ. All these processes gave good yields. Ⅲ was treated with sodium azide to afford Ⅳ, whose structure was determined by ^1H NMR and ^13C NMR.  相似文献   

2.
Thirteen new 2-alkylaminoimidazolones(4) wre rapidly synthesized by a new solution-phase parallel synthetic method,which includes aza-Wittig reaction of iminophosphorane(1) with aromatic isocyanate to give carbodi-imide(2) and subsequent reaction of 2 with various aliphatic primary amine in a parallel fashion.The products were confirmed by ^1H NMR,MS,IR and X-ray crystallographic analysis.The unusual selectivity of the cyclization was probably due to the deometry of the guanidine intermediate.  相似文献   

3.
The novel structures of organometallic compounds 3-biaryl-1-ferrocenyl-2-propene-1-ones 5 were synthesized for nonlinear optical chromophores by Suzuki cross-coupling reaction.Their structures were determined with elemental analyses,^1H NMR spectra and ^13C NMR spectra.  相似文献   

4.
A series of Biginelli compounds was synthesized using TsOH as a catalyst under microwave irradiation.This simple method provided the title compounds in 86%-98% yields by the reaction of aromatic aldehydes with 1,3-carbonyl compound and urea.The structure of 40 was determined by single crystal Xray diffraction analysis.  相似文献   

5.
Tumor marker CA15-3 was determined by using capilary electrophoretic enzyme immunoassay with electrochemical detection (CE-EIA-ED) ,The method can be used to detect CA15-3 with a limit of 0.024 U/mL.  相似文献   

6.
ZHANG  Yan WANG  Qin 等 《中国化学》2002,20(2):168-173
Treatment of 4-amino-3-(1-aryl-5-methyl-1,2,3-triazol-4-yl)-5-mercapto-1,2,4-triazoles/2-amino-5-(1-aryl-5-methyl-1,2,3-triazole-4-yl)-1,3,4-thiadiazoles with benzaldehyde,acetone and ω-bromoacetophenone was tested and compared.The title compounds Schiff bases,amides,imidazolo [2,1-b]-1,3,4-thiadiazoles and 7H-s-triazolo[3,4-b]-1,3,4-thiadiazines have been confirmed by elemental analyses,^1H NMR,IR and MS spectra.All the compounds have also been screened for their antibacterial activities against B.subtilis,S.aureus and E.coli.  相似文献   

7.
DeCai  HongYU 《中国化学快报》2002,13(11):1051-1054
In search of new anti-inflammatory and analgesic agents,(1H)-3,4-dihydro-pyrrolo [2,1-c][1,4]oxazin-1-one(3) and its acyl derivatives were designed and prepared .Compound 3 was prepared by treatment of methyl 1-(2-bromoethyl) pyrrole-2-carboxylate with silver oxide and its derivatives were obtained by Friedel-Carftes reaction.Nine of 6-acyl derivatives of compound 3 were prepared.  相似文献   

8.
The reaction of bis-benzimidazolium salts with sodium hydrogen telluride is reported,and a new synthetic method for dialdehydes is provided.  相似文献   

9.
盛寿日  黄宪 《中国化学》2003,21(4):471-473
This letter describes a method for the stereoselective synthesis of polymer-supported vinylic selenides and their applications to synthesis of(E)-and(Z)-1,2-disubstituted ethenes on solid-phase by the couplig reaction with Grignard reagents under the catalysis of NiCL2(PPh3)2.  相似文献   

10.
A series of novel compounds 3-(2-furyl)-4-aryl-1,2,4-triazole-5-thiones have been synthesized.All the compounds were characterized by spectral data and elemental analysis. The preliminary biological test showed that some of them exhibited excellent plant-growth regulative activities.  相似文献   

11.
1-苯基-3-甲基-5-氯吡唑-4-甲酸与氨基硫脲在三氯氧磷中反应得到2-氨基-5-(1-苯基-3-甲基-5-氯吡唑-4-基)-1,3,4-噻二唑(1), 然后分别采用超声辐射法和常规加热法与(未)取代苯甲酰基异硫氰酸酯(2)反应合成了一系列未见报到的1-[(未)取代苯酰基-3-[5-(1-苯基-3-甲基-5-氯吡唑-4-基)-1,3,4-噻二唑-2-基]-硫脲(3a3j). 化合物的结构经元素分析, IR, 1H NMR确证.  相似文献   

12.
Layered LiNi1/3Co1/3Mn1/3O2 has the isostructure of α-NaFeO2 and shows high rate capacity with stable cycleability. Furthermore, the thermal behavior of this material is milder than that of lithium nickel oxide and lithium cobalt oxide. In addition, it is expected to be stable at elevated temperatures. Therefore LiNi1/3Co1/3Mn1/3O2 may be the most promising cathode materials of lithium-ion secondary battery.In this research, LiNi1/3Co1/3Mn1/3O2 was prepared by solid-state reaction, sol-gel method and mixed hydroxide method. The influences of synthesis method on the physical and electrochemical properties of LiNi1/3Co1/3Mn1/3O2 were characterized by means of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), charge/discharge cycling cyclic voltammetry and differential scanning calorimetry (DSC). XPS studies show that the predominant oxidation states of Ni, Co and Mn in the LiNi1/3Co1/3Mn1/3O2 compound are 2+, 3+ and 4+. From the voltage profile and cyclic voltammetry, the redox processes occurring at ~3.8V and ~4.5V are assigned to the Ni2+/Ni3+ and Co3+/Co4+ couples, respectively. Different preparation methods result in the difference in morphology (shape, particle size and specific surface area) and electrochemical behaviors. A sample prepared by solid-state reaction has the worst electrochemical performance among these three methods. Sample synthesized by mixed hydroxide method displays the better rate capacity than that prepared by sol-gel method, while the capacity retention of sample prepared by sol-gel method is superior to that synthesized by mixed hydroxide method.  相似文献   

13.
B位掺杂GdCo1-xSrxO3的制备及其光催化活性   总被引:4,自引:2,他引:2  
用柠檬酸络合法制备了钙钛矿型GdCo1-XSrXO3(X=0.00, 0.02, 0.04, 0.06, 0.08)复合氧化物, 通过XRD, TEM 等手段对所生成纳米晶的物相结构、微观形貌、颗粒大小等进行了表征. 结果表明, 所合成的颗粒为钙钛矿型纳米晶, 球形. 通过其对活性艳红 X-3B 降解对其光催化活性进行了研究, 实验结果表明在B 位掺杂 Sr2+ 后使GdCoO3 的光催化活性明显提高, 当X=0.06 时, 即GdCo0.94Sr0.06O3 的光催化活性最佳.  相似文献   

14.
利用标准的固相反应法制备了La(1-x)2/3Ca(1/3)MnO3(x〈0.1)系列具有稀土La空位的庞磁电阻锰氧化物多晶样品.X射线粉末衍射(XRD)测量分析表明所有的样品均为单相,单胞具有正交对称性(Pnma).分析了不同浓度的La空位对磁电输运性质的影响: 随着空位浓度的增大,绝缘体-金属的转变温度(TMI)几乎不变(约为267 K),这表明少量的稀土空位不会破坏双交换作用;但当La空位浓度x〉0.04时,零场电阻率增大,但磁电阻(MR)值减小;在x=0.04时MR值在转变温度TMI处达到最大值约为220%(8 T).  相似文献   

15.
锂离子电池正极材料LiCo1/3 Ni1/3Mn1/3O2   总被引:2,自引:0,他引:2  
王希敏  王先友  罗旭芳  廖力 《化学进展》2006,18(12):1720-1724
镍钴锰三元材料作为锂二次电池正极材料是目前国内外研究热点。综述了三元材料近几年国内外的研究状况,重点介绍了LiCo1/3Ni1/3Mn1/3O2材料的结构与电化学性能的内在联系,探讨了不同制备方法及不同元素的掺杂改性对材料的影响,讨论了LiCo1/3Ni1/3Mn1/3O2正极材料的应用前景。  相似文献   

16.
共沸蒸馏法制备高性能LiNi_(1/3)Co_(1/3)Mn_(1/3)O_2正极材料   总被引:1,自引:0,他引:1  
三元复合氧化物镍钴锰酸锂(LiNi1/3Co1/3Mn1/3O2)因兼有LiNiO2和LiCoO2的优点,被认为是最有可能取代LiCoO2的新型正极材料而受到广泛关注.本文采用一种改进的共沉淀方法合成了LiNi1/3Co1/3Mn1/3O2,以共沸蒸馏干燥前驱物.结果表明,共沸干燥法最终得到的产物比普通干燥法得到的产物具有更高的比容量、更好的循环性能以及更优的倍率性能.究其原因,可归结为共沸干燥得到的样品颗粒更小,且粒径分布更均匀,球形度高,比表面积大,促进了锂离子的扩散,因而提高了其电化学性能.  相似文献   

17.
TiO2包覆对LiCO1/3Ni1/3Mn1/3O2材料的表面改性   总被引:1,自引:0,他引:1  
为了提高材料LiCo1/3Ni1/3MnO2的循环件能,采用浸渍-水解法对其进行TiO2包覆.用X射线衍射(XRD)、电化学交流阻抗谱(EIS)、电感耦合等离子体发射光谱(ICP-OES)和恒流允放电测试研究包覆材料的结构和电化学性能.TiO2仅在材料表面形成包覆层,并未改变材料的结构.TiO2包覆能提高材料LiCo1/3Ni1/3Mn1/3O2的倍率性能和循环性能,TiO2包覆后的材料在5.0C(1.0C=160 mA·g-1)下的放电容量达到0.2C下的66.0%,而包覆前的材料在5.0C下的放电容量仅为其0.2C下的31.5%.包覆后的材料在2.0C下循环12周后的容最没有衰减,而未包覆的材料容量保持率仅为94.4%.EIS测试表明包覆材料性能的提高是由于循环过程中材料的界面稳定性得到了提高.循环后材料的XRD和ICP-OES测试表明,包覆层能提高材料LiCo1/3Ni1/3Mn1/3O2的结构稳定性.  相似文献   

18.
建立了气相色谱法测定1,5-二叠氮基-3-硝基氮杂戊烷纯度标准物质中微量二氯甲烷、二甲基亚砜、1-羟基-5-叠氮基-3-硝基-3-氮杂戊烷含量的方法.样品以四氢呋喃作为溶剂进行溶解,采用RTX-1毛细管色谱柱(30 m×0.32 mm,5μm)和程序升温进行分离,外标法定量.线性相关系数(r)为0.999 0~0.99...  相似文献   

19.
Co(En)3MoO4晶体的水热合成与表征   总被引:1,自引:0,他引:1  
杂多酸的水热法合成的深入发展已引起了化学家的广泛关注[1~3].80年代已来,用水热合成方法得到了具有层状[4]、网状[5]、孔道状[6,7]和笼状[8,9]等多种新结构和新组成的杂多酸化合物,并应用于合成药物和研究催化剂等[10,11]工作中.科学家们已深入地了解了钒的氧簇化合物[12~15],但有关钼的氧簇化合物的研究还较少.杨国昱等[16]利用水热法合成了具有孔道结构的Ni(En)3MoO4纳米管.本文在此[16]基础上,利用水热法合成了具有网状结构的Co(En)3MoO4单晶.X射线分析结果表明,该晶体属六方晶系,P3C1空间群,晶体中阴阳离子通过静电吸引作用相互结合,形成一种有机-无机复合材料.  相似文献   

20.
利用琥珀酸为鳌合剂的湿化学法成功合成了一系列锂离子电池正极材料LiNi1/3Mn1/3Co1/3O2,在合成过程中改变琥珀酸与金属离子摩尔比(R)并研究了这一参数对合成LiNi1/3Mn1/3Co1/3O2材料物理及电化学性质的影响.采用热重、X射线衍射、Rietveld精修、扫描电镜以及超导量子干涉仪对反应机理、材料的结构、形貌以及磁学性质进行了详细表征.得到最佳合成条件为R=1,此时LiNi1/3Mn1/3Co1/3O2的阳离子混排度最低.此外,通过Rietveld精修得到该材料阳离子混排度的结果与通过磁学方法得到的结果定量相符,如对于在R=1条件下合成的样品,Rietveld精修结果显示其阳离子混排度为1.85%,而超导量子干涉仪的测试结果为1.80%.当充放电区间为3.0-4.3V,电流密度为0.2C(1C=160mA·g-1)时,该样品的首次放电容量为161mAh·g-1,库仑效率为93.1%,经过50次循环后,容量保持率可达91.3%.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号