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1.
读者来信     
《化学学报》1985年43卷第688页所刊《稀土聚乙炔电池及其电化学》一文,引起我很大兴趣.但细读之后,觉得该文存在一些问题.现就两个问题讨论如下: 关于电池平均功率密度问题该文笫688页第7行“结果表明:稀土聚乙炔电池……平均功率密度达160W/kg”.众所周知,平均功率密度P_(av)是电池工作性能的一个指标.其值为  相似文献   

2.
本文研究了稀土聚乙炔在水溶液中进行电化学掺杂和化学掺杂,及稀土聚乙炔的电位;用掺杂后的稀土聚乙炔作为水溶液体系一次电池的阴极,以镁作阳极构成半塑料电池;并研究了以稀土聚乙炔作为有机电解质体系可再充式电池的阴极,以锂作阳极的化学电源的电性能。  相似文献   

3.
<正> 聚乙炔掺入杂质后,做为高分子导电材料已引起人们的极大关注。有关聚乙炔(下称PA)的合成、结构及性能测试,以及电池研究已有很多报道,其催化剂体系已有关于Ti、V、Cr、W、Fe、Mo、Ni和Co等过渡金属化合物,稀土化合物合成PA的报道。本文进行了应用重元素钍的高配合物[Th(P_(204))_8Cl_4]与三乙基铝组合作为催化剂、使乙炔在常温下定向聚合的研究,得到具有余属光泽银白色的PA,顺式含量为80%,并对PA薄  相似文献   

4.
自从1977年白川英树等发现聚乙炔这种导电聚合物以来,打破了高分子材料长期以来被认为是绝缘体的观点。随后聚苯胺、聚吡咯、聚噻吩等的出现使导电聚合物的种类不断出新,其用途也扩展到如导电材料、电极材料、催化材料以及太阳能电池等应用中,且已有部分产品实现了商品化。其中,聚噻吩因其良好的稳定性、易于制备、掺杂后具有良好的光电化学性能等特点而受到广泛关注。本文总结了几种合成聚噻吩及其衍生物的常见方法,包括化学氧化聚合法、电化学聚合法、金属催化偶联法、光致合成法、光电化学沉积法,以及近年来新发现的固相聚合法和酸催化聚合法,并简要介绍了各自的合成机理及优缺点。  相似文献   

5.
聚乙炔是最有希望的导电高分子,目前己在开发应用于制造塑料电池、太阳能电池等。合成聚乙炔膜的主要催化剂有Ti(OC_4H_9)_4-Al(C_2H_5)_3催化剂,稀土络合催化剂及Co(NO_3)_2-NaBH_4等。本文报道新开发的周期表中第22号元素钛至第28号元素Ni的笫四周期过渡金属——Ti,V,Cr,Mn,Fe,Co,Ni的膦酸酯盐与三烷基铝组成的新络合催化剂合成聚乙炔膜的特征。除镍外,这些催化剂都可以使乙炔在室温下聚合生成顺式含量50%以上、高结晶性、有金属光泽的银灰色聚乙炔膜。在实验范围内,各催化体系聚合活性次序如下:Fe>Ti,V>Cr>Mn>Co>Ni,并且表征了所制备的聚乙炔膜,这些新催化剂的开发为合成聚乙炔提供了方便和有利条件。  相似文献   

6.
自1976年发现第一个有机聚合物聚乙炔掺杂后具有类似金属的导电性以来,先后发现了聚吡咯、聚噻吩和聚苯胺(PAn)等导电聚合物,其中聚苯胺以其合成方法简单、稳定性好、较高的电导率及良好的电化学性能等被预言为是最有应用前景的导电高分子材料之一。近年来,随着导电聚合物研究的广泛开展和不断深入,  相似文献   

7.
全固态锂电池具有优异的安全性能和能量密度,有望成为替代传统有机液态锂离子电池的下一代储能产品。固态电解质是决定全固态电池性能的关键材料,其中卤化物固态电解质,尤其是稀土溴化物固态电解质(RE-BSEs)材料近年来在离子电导率(高达mS/cm数量级)和电化学稳定性(1.5~3.4 V vs.Li^(+)/Li)等方面取得了一系列重要的研究进展,具有可期待的应用前景。本文通过对RE-BSEs的发展历程、研究进展、技术瓶颈、发展方向和应用前景等方面进行综述和回顾,给予研究人员在RE-BSEs的合成方法、锂离子传输机理、构效关系和材料设计等方面的参考和启发。稀土是我国乃至世界的重要战略资源,RE-BSEs材料的研究和重要成果明示了稀土元素在固态离子导体和新能源领域的重大价值,因此,做好稀土在该方面的研究工作对能源结构调整、节能减排、碳达峰和碳中和具有重大意义。  相似文献   

8.
钙钛矿型稀土氧化物价格低廉、结构可控、性质多样,在催化领域有着广阔的应用前景。本文从钙钛矿型稀土氧化物的结构类型、合成方法及电化学催化反应出发,总结了传统高温合成方法、火焰喷雾法、静电纺丝法和脉冲激光沉积法等几种最常用的合成方法,以及提升其氧析出反应(OER),氢析出反应(HER)和氧还原反应(ORR)催化能力的典型有效方法,概述了近年来钙钛矿型稀土氧化物在电解水、金属空气电池和固体氧化物燃料电池等能源转化储存装置的主要研究进展,进而对钙钛矿型稀土氧化物在能源转化储存领域的应用进行了展望。  相似文献   

9.
随着锂离子电池向电动汽车、可再生能源储能系统等大型应用领域发展,锂离子电池的能量密度、功率密度等性能指标需要进一步提高。在负极材料方面,传统的石墨碳负极材料的比容量有限,已经难以满足高能量密度电池的需求。以Si基材料为代表的新型高比容量负极材料受到了人们的广泛关注。其中,Si Ox材料在发挥高比容量的同时,具有相比纯Si更小的体积变化,因而在循环寿命方面更具实用潜力。本文对目前报道的Si Ox基负极材料的研究工作进行总结,系统阐述了Si Ox材料的基本电化学性能、结构模型、电化学机理及合成方法,分类介绍了改进Si Ox材料电化学性能的各类措施,并对其中Si O及无定形Si O2材料进行了重点论述。研究表明,氧含量、歧化程度、表面状态等对Si Ox材料的电化学性能具有重要影响;界面团簇混合(ICM)结构模型可更好地对其电化学机理进行理解;通过与第二相(碳、金属、金属氧化物等)复合,造孔,表面改性(包覆、刻蚀等)及其他手段(改变粘结剂及电解液)可有效提升Si Ox基材料的首次库仑效率和循环性能;部分使用Si Ox基材料的全电池具有循环600次后容量保持率达90%的优秀循环性能。Si Ox基材料已成为一种在高比能量锂离子电池中极具应用潜力的负极材料。  相似文献   

10.
双金属有机骨架及其衍生物一方面具有单金属有机骨架孔道丰富、比表面积大、结构可调、活性位点丰富等特点,另一方面具有双组分与多孔结构之间的协同效应,因而受到了研究人员的密切关注,在储能、催化、分离、传感器、医药、气体存储等领域广泛应用。和单金属MOFs类似,双金属MOFs的导电性不佳、结构易坍塌,这极大地限制了其在电化学储能中的应用。通过对双金属MOFs进行热处理,易得到分布均匀的多孔碳@双金属氧化物/硫化物/磷化物/硒化物等衍生物,不仅保持了独特的多孔结构,而且提高了材料的导电性和结构稳定性,有利于在电化学储能中的应用。因此,本文从双金属MOFs中的主要金属离子入手,综述了双金属MOFs及其衍生物用于超级电容器、锂离子电池、钠离子电池、金属空气电池等电化学储能器件的最新应用进展。在此基础上,总结了双金属MOFs在电化学储能应用中的优势,并对其制备、作用机理和后处理研究提出了建议。  相似文献   

11.
In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.  相似文献   

12.
KMnO4-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.  相似文献   

13.
The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.  相似文献   

14.
Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.  相似文献   

15.
An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.  相似文献   

16.
A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.  相似文献   

17.
The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp3)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp2)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp2)?H and aliphatic 1,5- and 1,6-C(sp3)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp3)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp2)?H insertion.  相似文献   

18.
The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.  相似文献   

19.
20.
Quercetin, the polyphenolic compound, which has the highest daily intake, is well known for its protective effects against aging diseases and has received a lot of attention for this reason. Both quercetin 3-O-β-d-glucuronide and quercetin 3′-O-β-d-glucuronide are human metabolites, which, together with their regioisomers, are required for biological as well as physical chemistry studies. We present here a novel synthetic route based on the sequential and selective protections of the hydroxyl functions of quercetin allowing selective glycosylation, followed by TEMPO-mediated oxidation to the glucuronide. This methodology enabled us to synthesize the five O-β-d-glucosides and four O-β-d-glucuronides of quercetin, including the major human metabolite, quercetin 3-O-β-d-glucuronide.  相似文献   

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