BaCe0.5Zr0.4Y0.1O3-α的溶胶-凝胶法制备及其电性能

采用溶胶-凝胶法, 以低于固相合成法150～250 ℃的温度进行烧结, 分别制备了BaCe0.9Y0.1O3-α和BaCe0.5Zr0.4Y0.1O3-α固体电解质. 应用AUTOLAB PGSTA 30型电化学工作站测定了两种电解质在不同温度下的阻抗谱, 在350～800 ℃范围内电导率分别为1.62×10-4～6.43×10-3 S·cm-1, 2.52×10-5～3.73×10-3 S·cm-1, 电导激活能分别为0.54和0.84 eV. 同时用高温固相合成法合成了BaCe0.9Y0.1O3-α质子导体, 在相同条件下其电导率为1×10-4～4×10-3 S·cm-1, 激活能为0.50 eV. 实验结果表明 用溶胶-凝胶法得到的材料在烧结温度低于固相合成法150～250 ℃的情况下, 制备出的样品电导率高;对于同一质子导体BaCe0.9Y0.1O3-α, 用Zr代替部分Ce, 固体电解质的电导率明显降低.     

BaCe0.8Ln0.2O2.9(Ln=Gd, Sm, Eu)固体电解质的低温制备及其燃料电池性质

利用溶胶 凝胶法低温合成了BaCe0 .8Ln0 .2 O2 .9(Ln =Gd ,Sm ,Eu)固体电解质 ,X射线粉末衍射表明 90 0℃即形成正交钙钛矿结构 ,较高温固相反应合成温度降低了约 6 0 0℃ .测定了样品的阻抗谱和电导率 ,研究了其导电机理 ,溶胶 凝胶法合成可减小或消除固体电解质的晶界电阻 ,80 0℃时BaCe0 .8Gd0 .2 O2 .9的σ =7.87× 10 -2S·cm-1,以它为电解质的氢氧燃料电池开路电压接近 1V ,最大输出功率密度为 30mW·cm-2 .     

辐照交联法制备锂离子电池用凝胶聚合物电解质及其性能

采用γ-射线辐照交联法制备了具有网络结构的聚偏氟乙烯-六氟丙烯/新戊二醇二丙烯酸酯(PVDF-HFP/NPGDA)基凝胶聚合物电解质(GPE). 考察了不同辐照剂量对凝胶电解质形貌结构、热稳定性和电化学性能的影响以及不同辐照剂量和不同温度下电导率的变化. 结果表明, 随辐照剂量的增加, 凝胶电解质的固化程度提高, 电导率下降. 电导率随温度的变化符合VTF方程. 当辐照剂量为5 kGy 时, 制备的凝胶电解质具有较高的离子电导率和电化学稳定窗口, 室温下分别为7.8×10-3 S·cm-1和4.7 V(vs Li/Li+). 以其为电解质制备的LiMn2O4∣GPE∣Li聚合物锂离子电池具有较好的循环性能.     

(Ce0.8RE0.2)1-xMxO2-δ固体电解质的溶胶-凝胶合成及其电性质

利用溶胶 凝胶法合成了 (Ce0 .8RE0 .2 ) 1-xMxO2 -δ(RE :稀土 ,M :碱土 )系列固体电解质 ,XRD表明 80 0℃即形成萤石结构 ,较高温固相反应合成温度低约 70 0℃ .测定了样品的电导率和阻抗谱 .XPS测试表明 ,掺杂碱土氧化物后吸附氧浓度明显增大 ,氧空位增多 ,电导率和氧离子迁移数增大 ,改善了CeO2 基固体电解质的性能 .讨论了碱土及稀土离子对电性质的影响 .(Ce0 .8Sm0 .2 ) 1-0 .0 5 Ca0 .0 5 O2 -δ80 0℃时电导率0 1 2 6S·cm-1,氧离子迁移数 0 .99.     

一种新型聚合物电解质的研制

合成了聚 (甲基丙烯酸甲酯 丙烯腈 甲基丙烯酸锂 ) (简记为PMAML)新型聚合物电解质基质材料 ,把它与聚偏氟乙烯 (PVDF)共混制备了凝胶化的聚合物电解质 .通过核磁共振波谱确定了PMAML的组份含量 ,并用扫描电镜观察了该聚合物基质膜的表面形貌 .利用交流阻抗技术测试了其电导率 ,室温下电导率可达2 5× 10 - 3S·cm- 1 .采用线性伏安扫描方法研究了该聚合物电解质的电化学稳定性 ,其电化学稳定窗口为4 5V .通过受限扩散实验测得电解质中离子的扩散系数为 8 12× 10 - 7cm2 ·s- 1 .组装的聚合物电解质锂离子电池首次充放电效率为 89% ,前 5次循环容量基本稳定 .     

分子凝胶电解质的电导率研究

凝胶因子4,4'-二(硬脂酰胺基)二苯醚(BSDE)在水和非水介质(如二甲基甲酰胺、二甲基亚砜、碳酸丙烯酯等)中利用非共价键相互作用自组装成有序的三维纤维网络结构,使介质凝胶化.该凝胶被称之为分子凝胶.同样,BSDE也能使锂盐溶液凝胶化,制备一种新型分子凝胶电解质.水分子凝胶锂离子电解质的室温离子电导率达到10^-1～10^-2S·cm^-1,碳酸丙烯酯分子凝胶锂离子电解质的室温离子电导率也能达到10^-2～10^-3S·cm^-1.分子凝胶的离子电导率研究表明,锂盐在凝胶中的行为和其在溶液中的行为相似.在-35℃的低温下,分子凝胶的电导率与其溶液相比约低1～2个数量级.     

La10-x(SiO4)6O3-1.5x的合成及其导电性能的研究

利用溶胶-凝胶法在800 ℃合成了硅酸盐氧基磷灰石La10-x(SiO4)6O3-1.5x(x=0,0.17,0.33,0.50和0.67),经XRD表征所得产品为磷灰石相.以电化学阻抗谱研究了硅酸盐氧基磷灰石的导电性能,体系的电导率随着间隙氧和阳离子空位数量的增多而加大,La9.33(SiO4)6O2的电导率较La9.5(SiO4)6O2.25大,是由于前者有较多的阳离子空位所致,700 ℃时La10(SiO4)6O3的电导率为7.98×10-3 S·cm-1,比La9.33(SiO4)6O2的电导率提高了5倍.氧分压从105～1 Pa变化时电导率保持不变,证明硅酸盐氧基磷灰石在较宽的氧分压范围内为O2-导电.     

La1.95Sr0.05Mo2O9固体电解质的电性质

采用溶胶-凝胶法合成了La1.95Sr0.05Mo2O9固体电解质材料,采用SEM,XRD,交流阻抗谱、气体浓差电池、氧泵等方法对样品进行了表征.结果表明,制得的样品为立方结构;在600～1000℃下氧浓差电池电动势的实测值与理论值吻合得很好,氧离子迁移数为1,表明该陶瓷样品在该温度下氧气气氛中为一纯氧离子导体;离子电导率随温度升高而增大,1000 ℃时达到最大值0.12 S·cm-1.高于相同条件下母体的电导率(0.03 S·cm-1).     

聚合物固体电解质中的离子状态与导电机理的研究

制备得到了一种新颖的聚氨酯和丙烯酸酯复合梳形交联聚合物 (Combcross linkedpolymer) ,并以此聚合物为基体加入不同含量的高氯酸锂盐制得一系列聚合物固体电解质 ,其室温电导率可以达到 3 4× 10 - 5S·cm- 1 .通过Raman、DSC、SEM及电性能等研究了电解质中的盐浓度与离子存在状态及离子电导率之间的关系 .结果显示随着盐浓度的增加 ,聚合物固体电解质中离子对的比例和电导率都迅速增加 ,说明离子对 (由多个醚氧原子、阴离子和阳离子组成 )对体系导电起着积极的作用 .     

原位复合法制备(PEO)8LiClO4/TiO2聚合物电解质的研究

以聚氧化乙烯/高氯酸锂复合物[(PEO)8LiClO4]为基体,通过钛酸丁酯的水解缩合反应在其中原位生成TiO2,制备了(PEO)8LiClO4/TiO2复合聚合物电解质,采用SEM、DSC和交流阻抗方法研究了聚合物电解质的形态、玻璃化转变温度(Tg)、结晶度(Xc)和离子导电性能.结果表明原位生成的TiO2在基体中分散均匀,加入TiO2后聚合物电解质体系的Tg和Xc均有所降低,而电导率明显提高,当TiO2添加量为ω=0.05时电导率达到最大值5.5×10-5S·cm-1(20℃).     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

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.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

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.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

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.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

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.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Microwave-assisted copper-catalyzed stereoselective ring expansion of three-membered heterocycles with α-diazo-β-dicarbonyl compounds

Microwave-assisted copper-catalyzed ring expansions of three-membered heterocycles with α-diazo-β-dicarbonyl compounds were investigated. Thiiranes generated 3-acyl-5,6-dihydro-1,4-oxathiines in the presence of copper sulfate and trans-3-acyl-5,6-dihydro-1,4-oxathiines as stereospecific products for 1,2-disubstituted cis-thiiranes through an intramolecular S_N2 process. Oxiranes gave rise to 2-acyl-5,6-dihydro-1,4-dioxines under the catalysis of copper hexafluoroacetylacetonate and cis-3-acyl-5,6-dihydro-1,4-dioxines as stereospecific products for 1,2-disubstituted cis-oxiranes via an intimate ion-pair mechanism. The current method provides a direct and simple strategy in efficient preparation of 3-acyl-5,6-dihydro-1,4-oxathiines and 2-acyl-5,6-dihydro-1,4-dioxines, important agents in medicinal and agricultural chemistry, from readily available thiiranes and oxiranes, respectively.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

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.