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1.
The electrochemical dissolution of metallic lanthanum in ethanol (EtOH) is studied in the presence of 0.5 M lithium chloride with acetylacetone (HAA), dibenzoylmethane (HDBM), tenoyltrifluoroacetone (HTTA), and benzoylacetone (HBA). Adducts of lanthanum tris--diketonates, specifically, La(AA)3 · 0.5EtOH, · La(DBM)3· 2EtOH, La(TTA)3 · 1.5EtOH, and La(BA)3 · EtOH are extracted from solution. Electrooxidation of lanthanum during electrolysis is accompanied by its chemical dissolution. The composition of the obtained compounds is confirmed by IR spectroscopy, thermogravimetry, isothermic heating, and elemental analysis for the metal.  相似文献   

2.
乙酰丙酮钛螯合物掺杂丙烯酸酯共聚物水溶胶;乙酰丙酮钛螯合物; 丙烯酸酯共聚物水溶胶;掺杂  相似文献   

3.
齐贵中  沈琪 《应用化学》1997,14(2):108-109
二价芳氧钐配合物催化苯乙烯聚合齐贵中扈晶余*沈琪(中国科学院长春应用化学研究所稀土化学与物理开放实验室长春130022)(苏州大学化学系苏州)关键词钐配合物,苯乙烯,聚合1996-05-18收稿,1996-10-30修回国家科委攀登计划及国家自然科学...  相似文献   

4.
IntroductionAntimony freePb Caalloyshavecommonlybeenusedinthemanufactureofgridsinordertominimizegassingineitherlow maintenanceorvalve regulatedleadacidbatteries .However ,thesealloyscancauseotherproblemssuchasprematurecapacityloss ,lowcharge ac ceptanceand…  相似文献   

5.
The effects of samarium on the properties of the anodic Pb(II) oxides films formed on lead at 0.9 V (vs. Hg/Hg2SO4) in 4.5 mol/L H2SO4 solution were studied using linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS) and scanning electron micrographs (SEM). The experimental results show that adding Sm to lead metal can inhibit the growth of the Pb(II) oxides film effectively, and reduce the resistance of the PbO oxides film obviously. The addition of Sm increases the porosity of the anodic film, which may cause the increase of the ionic conductance produced by the interstitial liquid among the PbO particles in the film and lead to the decrease of the resistance of the anodic film.  相似文献   

6.
In the early eighties, we introduced samarium diiodide for the transformation of various functional groups. Since then, this reducing agent has been extensively used for the reductive cleavage of single bonds, C‐C bond formations, C‐N bond formations, and β‐elimination reactions. In this Personal Account, we highlight our initial results, as well as some of the contributions from various research groups. Because of space limitations, we arbitrarily select some useful results that have recently been described in literature.  相似文献   

7.
Introduced by Henri Kagan more than three decades ago, samarium diiodide (SmI2) has found increasing application in chemical synthesis. This single‐electron reducing agent has been particularly useful in C? C bond formations, including those found in total synthesis endeavors. This Review highlights selected applications of SmI2 in total synthesis, with special emphasis on novel transformations and mechanistic considerations. The examples discussed are both illustrative of the power of this reagent in the construction of complex molecules and inspirational for the design of synthetic strategies toward such targets, both natural and designed.  相似文献   

8.
钐试剂在有机合成中应用的若干新进展   总被引:1,自引:0,他引:1  
刘永军  张永敏 《化学学报》2005,63(5):341-351
综述了本课题组最近几年关于钐试剂在有机合成中应用的研究进展. 主要包括以下几部分内容: (1) 二碘化钐促进的有机反应研究; (2) 金属钐直接应用于有机合成的研究; (3) 其它钐试剂 (三碘化钐, 烯丙基溴化钐) 促进的有机反应研究.  相似文献   

9.
建立乙酰丙酮分光光度法测定土壤中甲醛含量的分析方法。在磷酸介质中,土壤中的甲醛经过加热蒸馏提取,与乙酰丙酮反应生成黄色的二乙酰基二氢二甲基吡啶,然后于412 nm波长处测定其吸光度。甲醛含量在0.0~25μg范围内与吸光度呈良好的线性关系,线性相关系数r=0.999 6,加标回收率为76.2%~87.5%,方法检出限为0.03 mg/kg,定量限为0.12 mg/kg,测定结果的相对标准偏差为2.73%~3.68%(n=6)。该方法灵敏度高,分析速度快,适用于土壤中甲醛含量的测定。  相似文献   

10.
11.
二(2,6-二叔丁基-4-甲基苯氧基)钐配合物催化甲基丙烯酸甲酯聚合扈晶余,齐贵中(中国科学院长春应用化学研究所稀土化学与物理开放实验室长春130022)沈琪(苏州大学化学系苏州)关键词钐配合物,甲基丙烯酸甲酯,聚合二价稀土有机化合物具有很强的还原性...  相似文献   

12.
碱性水电解阳极材料研究进展   总被引:8,自引:0,他引:8  
王鹏  姚立广  王明贤  吴维 《化学进展》1999,11(3):254-264
本文述评了对工业电极材料的基本要求和提高阳极活性的几种途径, 列举了一系列用于碱性水电解的活性阳极材料, 在分析了材料物理化学特性与其催化活性之间的关系后, 着重利用σ*键理论和MO 理论讨论了结构与性能之间的关系。  相似文献   

13.
电极液酸度及稀土浓度对硫酸体系电解还原提纯镱的影响   总被引:1,自引:1,他引:1  
研究了在硫酸体系中,采用钌铱钛合金网为阳极,金属汞为阴极,在无惰性气氛的保护下,尝试电解还原镱,在诸多电极条件实验中着重研究了阳极液酸度、阴极液酸度以及料液浓度变化时电流、目标离子的还原率等电解还原过程的变化。研究表明,当阳极液酸度为2.0 mol.L-1,阴极液pH=0.3,阴极液稀土料液浓度为0.5 mol.L-1时,镱的还原率可达95%以上,硫酸镱纯度达到99%以上,稀土总回收率高于99%。  相似文献   

14.
15.
纯铝在强碱溶液中阳极溶解的电化学阻抗谱解析   总被引:2,自引:0,他引:2  
依据曹楚南提出的法拉第导纳表达式,拟合了纯铝在强碱溶液中的阳极溶解过程的电化学阻抗谱,并据此提出了这一反应进行的机理.结果表明,阻抗谱中的低频容抗弧是由表面裸露的Al转变为中间产物Al(OH)ads的反应引起的,而中频感抗弧则由Al(OH)ads转变为Al(OH)3,ads的反应引起.法拉第导纳的时间常数τ1和τ2的物理意义是物种Al(ss)和Al(OH)ads在单位表面活性位上的转化时间. τ1 >0和τ2 >0是符合稳定性条件的,也能够满足Kramers-Kronig转化的必要条件. g1和g2是与物种Al(ss)和Al(OH)ads在电极表面的覆盖密度随电位E变化有关的参数,由g1< 0可知随电位升高,纯铝表面的活性位面积减小.  相似文献   

16.
We report an efficient electrolytic procedure for the reduction of aldehydes to primary alcohols in the absence of dimeric products. In this promising approach, based on environmentally friendly chemical synthetic methods, a simple electrolytic undivided cell was designed. Two copper plates served as electrodes and recycled water as the medium. A 6-V battery provided the required energy. Although initially the method was intended for the preparation of 2-aryl-3-hydroxymethyl imidazo[1,2-a]azines, it was successfully extended to reduce other aliphatic and aromatic aldehydes. The attractiveness of this procedure includes its operational simplicity, practical viability, inexpensiveness and good yields. In most cases the results were better than those obtained with the standard reduction procedure using sodium borohydride.  相似文献   

17.
The selective deprotection of a benzoyl group was very important methodology in the field of organic synthesis. Various methods for debenzoylation were investigated and developed in the past six decades, but more useful and selective strategies are now being strongly desired. In response to this strong demand, we developed the novel and selective deprotection of a benzoyl group by use of samarium(II) dibromide and a proton source. This deprotective reaction proceeded smoothly and the desired compound was obtained in good to excellent yields. In this paper, we will report the details of this deprotective reaction.  相似文献   

18.
钐试剂在有机合成中的应用   总被引:2,自引:0,他引:2  
本文综述了钐试剂在有机合成中的应用,包括还原反应,碳-碳键形成反应以及催化作用。  相似文献   

19.
以目前使用的6 k A稀土电解槽为研究对象,采用实验验证与数值模拟计算相结合的方式对采用不同阳极结构的稀土电解槽进行了全面分析讨论。使用斜角切割阳极片可以在维持电解槽槽电压、氧化物利用率、产品合格率等技术指标不变的情况下,克服传统正交切割阳极片在使用过程中随着阳极片反应消耗造成电流效率降低及缩短石墨坩埚使用寿命的现象。其可作为稀土电解槽工艺改造的一个发展方向。  相似文献   

20.
Nonstoichiometric series SmF_x (2.0≤x≤3.0) have been synthesized by reduction of samarium trifluoride with hydrogen for several times, and the stoichiometric samarium difluoride has been obtained. The structure of nonstoichiometric samarium fluoride series and the valency of samarium ion are briefly discussed. The valent change process of samarium ion at high temperatures in different atmospheres is investigated.  相似文献   

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