Freezing points,osmotic coefficients,and activity coefficients of some salts in ethylene carbonate: A high dielectric constant solvent without hydrogen bonding

The freezing points, conductivities, and densities of NaI, KI, CsI, Bu₄NCl, Bu₄NBr, Bu₄NI, Et₄NBr, and Pr₄NBr (where Et = ethyl, Pr = propyl, and Bu =n-butyl) in ethylene carbonate have been measured. Osmotic and activity coefficients were calculated from the results. All of the salts studied are strong electrolytes. The trends in the osmotic coefficients of the alkali metal iodides are NaI>KI>CsI, showing that Na⁺ is more solvated by ethylene carbonate than Cs⁺. For the tetraalkylammonium halides, the order of osmotic coefficients are Et₄NBrPr₄NBrBu₄NCl>Bu₄NBr>Bu₄NI. This is the same order as observed in two other high-dielectric-constant solvents, water andN-methylacetamide. The results indicate that the smaller anions are more solvated than the larger anions in ethylene carbonate in contrast to the usual behavior of dipolar aprotic (basic) solvents, such as dimethyl sulfoxide.     

Preparation and Characterization of Trimethylsilylpyridylacetylene Bridged,Dicobalt Carbonyl Complexes Containing Bis(diphenylphosphino)methylene or Bis(diphenylphosphino)ethylene Ligand

Reaction of an alkyne‐bridged dicobalt complex, [Co₂(CO)₆(μ‐Me₃SiC=Cpy)] 4 , with bis(diphenylphosphino)methylene (DPPM) or bis(diphenylphosphino)ethylene (DPPE) in THF at 55 °C yielded a DPPM or DPPE doubly bridged dicobalt compound, [{μ‐P,P‐PPh₂CH₂PPh₂}Co₂(CO)₄(μ‐Me₃SiC=Cpy)] 5 or [{μ‐P,P‐PPh₂CH₂CH₂PPh₂}Co₂(CO)₄(μ‐Me₃SiC≡Cpy)] 6 . Compound 5 and 6 were characterized by spectroscopic means as well as X‐ray crystal structure determination.     

反相高效液相色谱法分析超临界甲醇解聚聚对苯二甲酸乙二醇酯的产物

配合超临界甲醇解聚聚对苯二甲酸乙二醇酯的工艺开发,采用高效液相色谱法对聚对苯二甲酸二乙酯的超临界甲醇解聚固体产物进行了分离、定性和定量分析。采用反相色谱体系,色谱柱为Zorbax-C8柱,流动相为甲醇－水（70／30,V／V）,紫外检测器。该法具有高色谱分辨率、简便、准确、重复性好等特点。     

涤纶工业丝等温收缩中的结构变化

采用广角X 射线衍射、密度梯度、声速和差示扫描量热等实验方法对 145 5dtex/ 110f成品涤纶工业丝等温收缩的结构变化进行了表征 ,外加张力为 0 3N ,测定温度范围 375～ 494K .结果表明 ,涤纶工业丝的热收缩在宏观上表现为速率不同的两个过程 ,对应两种不同机理 .其中快过程对应非晶区的解取向 ,对收缩的贡献是主要的 ;慢过程对应晶区的变化 ,包含了晶粒的增长 ,新的不完善晶粒的形成和晶区的完善 .晶粒的增长在较短的时间内基本完成 ,再结晶则存在于整个收缩过程 .随温度的升高 ,晶区变化速度明显加快 ,对非晶区解取向的抑制效应因此变大 .     

Candida antarctica B Lipase-Loaded Microreactor for the Automated Derivatization of Lipids

A key bottleneck in the profiling of lipids is the multistep derivatization required prior to gas chromatography (GC) analysis. A single in-vial lipid derivatization and analysis may significantly minimize sample loss and improve analytical sensitivity. A cotton fiber-supported poly(glycidylmethacrylate-co-ethylene glycol dimethacrylate) polymer microbrush microreactor loaded with Candida antarctica lipase B was developed for the facile conversion of triacylglycerols into fatty acid ethyl ester derivatives for gas chromatograph–mass spectrometry (GC–MS) analysis. The polymer microbrush microreactor was fabricated in effort to provide efficient, simplified, cost effective, and high-throughput GC–MS determination of triacylglycerols. The polymer microbrush microreactor was used as an in-vial triacylglycerol transesterification platform, with economical sample consumption of less than or equal to 100?µL and significant reduction of reagents. To evaluate the polymer microbrush microreactor performance for lipids, a triolein standard and camelina oil triacylglycerols were quantitatively transformed into ethyl oleate and fatty acid ethyl esters, respectively, following a 3?h reaction time. The lipase-loaded cotton fiber-supported poly(glycidylmethacrylate-co-ethylene glycol dimethacrylate) polymer microbrush microreactors were reusable for up to five times for quantitative transesterification with minimal loss of lipase activity.     

A new titanium (IV) complex bearing phenoxyimine‐fluorene ligand and its use as catalyst for ethylene homo‐ and copolymerization

A new titanium (IV) complex bearing phenoxyimine‐fluorene ligand was prepared and its behaviors in ethylene homo‐ and copolymerization with 1‐hexene, 1‐octene, and norbornene in the presence of modified methylaluminoxane (MMAO) were studied respectively. The effects of various polymerization conditions including polymerization temperature, ethylene pressure and the concentration of comonomer on the catalytic activities and properties of the resultant polymer were investigated. The broad molecular weight distribution of resulting polymer indicated that the multiple active species were formed during polymerization. Such complex showed good catalytic activities in ethylene homo‐ and copolymerizations and good capabilities of incorporating various comonomers into polyethylene backbone. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1617–1621, 2010     

Progress on High Voltage PEO-based Polymer Solid Electrolytes in Lithium Batteries

Polymer electrolytes have attracted great interest for next-generation lithium-based batteries on account of safety and high energy density. In this review, we assess recent progress on the design of poly(ethylene oxide)(PEO)-based solid polymer electrolytes in high voltage lithium batteries and identify possible side reactions between PEO-based electrolytes and existing cathodes. We provide an overview of the ways to enhance high voltage resistance of PEO-based electrolytes. Those include components blend, molecular design and interface modification. With these efforts, we want to present new insights into rational design of PEO-based electrolytes to develop solid-state lithium batteries for advanced performance.     

Effect of pressure on the low-temperature reaction of ethylene with N2O4

Calorimetric monitoring of the autoclave reaction N₂O₄ + C₂H₄ at –85 to +10 °C under argon pressure 10–30 bar revealed that the exothermic chemical reaction started at temperatures above –52 °C at 10 bar, whereas an intensive exothermic reaction started at –85 °C and pressure of 30 bar. IR study showed that oligo/polynitroethylene was formed at 30 bar, while carbonyl and hydroxy compound as well as nitrate R–ONO₂ formation occurred upon processing at 10 bar.     

四氟乙烯-乙烯溶液沉淀聚合

本文编制了一个简易计算机程序,测定了氟氯烷溶液沉淀聚合体系中四氟乙烯-乙烯共聚竞聚率:40℃:γC_2H_4=0.156±0.001,γC_2F_4=0.022±0.01670℃:γC_2H_4=0.197±0.001,γC_2F_4=0.055±0.020在此聚合体系中,聚合温度和共聚物组成比对链的规整性都有明显影响。当乙烯在45～55mol%范围内时,共聚物的IR随组成比而变化,利用此规律可简便地测定共聚物的组成比。     

Ni基乙烷脱氢催化剂的性能及其改进

过渡金属Ni是地球上储量丰富的金属元素, 在加氢脱硫、重整制氢等催化领域应用非常广泛, 但是关于Ni基催化剂在烷烃脱氢方面的研究较少; 因此, 本工作采用不同的方法, 制备了三种结构的Ni基负载催化剂, 即尖晶石分解型、浸渍型和钙钛矿析出型, 并在700 ℃、C₂H₆-N₂气氛中和50 mL•min^-1气体流速下, 探索了它们的乙烷脱氢性能. 结果表明: 尖晶石分解型催化剂Ni_1-xCu_xCr₂O₄还原后在Cr₂O₃表面形成Ni-Cu合金颗粒, 能有效钝化Ni的C—C键断裂活性, 提高乙烯的选择性. Ni含量过高时, Ni不能有效地分散而形成大的金属团簇, 造成乙烷过度裂解, 乙烯选择性较低. 浸渍负载型催化剂Ni_xM_y/Al₂O₃ (M为Cu或Ag) 比表面积大, 表面活性位点分散, 但活性金属与载体结合力弱, 在高温下不稳定; Cu或Ag与Ni形成合金, 可有效提高乙烯选择性, Ag较Cu的效果更佳. 钙钛矿析出型催化剂LaCr_1-xNi_xO₃(LCNi-100x)在还原气氛中析出均匀细小的Ni颗粒, 其与基体结合力强, 抗积碳性能和稳定性较高; 含15% Ni的LCNi-15还原后(R-LCNi-15)表现出最好的催化性能, 乙烯产率最高(24%), 同时具有较好的抗积碳性能和稳定性以及氧化再生性.