氯化1-{2-[双(2-氨基乙基)氨基]乙基}吡啶离子液体的合成及在ATRP反应中的应用

采用N-烷基化方法将二乙烯三胺（DETA）接枝到氯化1-氯乙基吡啶离子液体[CePy]Cl上,合成了离子液体氯化1-{2-[双（2-氨基乙基）氨基]乙基}吡啶（[N₃Py]Cl）,通过FTIR、¹H NMR和MS等测试手段对合成离子液体的结构进行了表征。采用循环伏安法对离子液体配合物[N₃Py]Cl/CuBr和有机配合物PMDETA/CuBr的氧化还原电位（E_1/2）进行测试,结果表明：合成的离子液体[N₃Py]Cl和CuBr形成配合物的氧化还原电势为E_1/2=-0.541V,比常用的有机配合物PMDETA/CuBr（E_1/2=-0.142V）具有更低的氧化还原电势。将离子液体[N₃Py]Cl与CuBr配位形成催化体系,在离子液体[AMIM]Cl中催化甲基丙烯酸甲酯（MMA）的原子转移自由基聚合（ATRP）反应。结果表明,当配体、催化剂和溶剂的用量分别为n（CuBr）=0.19mmol、n（[N₃Py]Cl）=1.13mmol、n（[AMIM]Cl）=0.02mol,反应温度60℃,反应时间4h时,单体转化率高达75%,分子量分布较窄（M_w/M_n=1.24）,ATRP反应具有明显的可控性能。     

Methane activation by surface oxygen in calcia-stabilized zirconia

Methane activation at 450–700°C by 14 mol% calcia-stabilized zirconia was studied by the transient reaction of pure methane with the oxidized material. Three distinct sequential reaction regimes are observed. Initially, methane oxidation rates are similar to those in cofed methane–oxygen mixtures. After a small amount of oxygen (amount) is removed from the material, the reactivity of the material suddenly increases while a larger amount of oxygen, roughly equivalent to 1 surface layer, is removed. Finally, after this reductive phase, methane continues to react rapidly to deposit a surface layer of carbonaceous material which can be removed by reoxidation. This cycle can be repeated.     

Electrochemical comparison of IrO2 prepared by anodic oxidation of pure iridium and IrO2 prepared by thermal decomposition of H2IrCl6 precursor solution

Surface redox activities, oxygen evolution reaction (OER), oxidation of formic acid (FA), and anodic stability were investigated and compared for IrO₂ electrodes prepared by two techniques: the thermal decomposition of H₂IrCl₆ precursor (TDIROF) and the anodic oxidation of metallic iridium (AIROF). Surface redox activities involved on the AIROF were found to be much faster than those involved on the TDIROF. Concerning the oxygen evolution reaction, both films show a similar mechanism and specific electrocatalytic activities. The situation seems to be different for FA oxidation. In fact, on TDIROF, the oxidation of FA and the OER compete involving the same surface redox couple Ir(VI)/Ir(IV) contrary to FA oxidation on AIROF, where the Ir(V)/Ir(IV) surface redox couple is involved. Finally, electrode stability measurements have shown that contrary to TDIROF, which are very stable under anodic polarization, the AIROF are rapidly corroded under anodic treatment. This corrosion is enhanced even further in the presence of formic acid.     

四种乳酸聚合方法的比较

以乳酸为原料,辛酸亚锡为催化剂,采用乳酸直接聚合(一步法)、丙交酯开环聚合(两步法)、熔融-固相聚合、溶剂回流脱水等不同的实验方法分别合成出了不同相对分子质量的聚乳酸。实验结果表明:实验方法不同,所得聚合物的相对分子质量不同,其中丙交酯开环聚合(两步法)所得聚合物的相对分子质量最大,可达80万左右,溶剂回流脱水法的可达24000左右,熔融-固相聚合的为10800,乳酸的直接聚合(一步法)的只有5000。     

对苯二胺改性间位芳香族聚酰胺的合成及热性能研究

采用低温溶液法共缩聚反应合成了5%￣15%的对苯二胺(PPDA)改性间位芳香族聚酰胺(PMIA)共聚物。用1HNMR对改性共聚物进行了分析,讨论了PPDA的含量对共聚物比浓对数黏度的影响;对改性聚合物和PMIA纤维进行了热失重分析,并用红外光谱跟踪法探讨了PMIA和共聚物的热降解过程。实验结果表明,用PPDA改性后的共聚物具有更优异的热性能。     

高压脉冲放电降解水溶液中4-氯酚过程的数学模型(Ⅱ)鼓泡过程中臭氧传质增强因子E与4-氯酚浓度的关系

臭氧从气相传质到废水溶液中并与其中的有机污染物发生氧化还原反应是一个含有化学反应增强的臭氧吸收过程.在酸性废水中主要发生臭氧与4-氯酚分子和4-氯酚盐离子的反应,而臭氧在水溶液中分解形成的羟基自由基的氧化作用可以忽略.提出了由于发生化学反应而形成的臭氧传质增强因子E与废水中有机物浓度［PCP］的定量关系的表达式.     

Thermal degradation behavior of PMMA synthesized by emulsifier‐free emulsion polymerization with a Cu2+/HSO3− redox system

In this study, poly(methyl methacrylate) (PMMA) latex was synthesized in an emulsifier‐free emulsion polymerization at 60°C using a Cu²⁺/HSO redox initiator system with different concentrations of Cu²⁺. The experimental results showed that the monomer conversion reached above 90% for all systems. Zeta potential was all negative due to the bonded bisulfite ion and the magnitude was greater than 30 mV, providing the stability of PMMA emulsion. The morphology of the latex observed by scanning electron microscope revealed a uniform particle size, and the average particle size increased from 181.9 to 234.2 nm as the Cu²⁺ ion concentration increased from 2.0 to 6.0 mM in 1M of MMA solution. Thermal degradation behavior of synthesized PMMA was studied by thermogravimetric analysis, in which a two‐stage degradation behavior was observed. These two stages were found to be caused by the degradation of unsaturated end group (PMMA? CR?CH₂) and saturated end group (PMMA? H), respectively. In addition, the higher the concentration of Cu²⁺ ion, the greater the proportion of PMMA? CR?CH₂ in the final product, and in turn rendering more weight loss in the first‐stage degradation. The copper ion not only played a role in the redox initiation, but also acted as a chain transfer agent to terminate growing polymer chains, thus producing PMMA? CR?CH₂. The apparent activation energies of the first stage (E_a1) and second stage (E_a2) were calculated by Ozawa's and Boswell's method. The results showed that E_a1, representing the degradation of PMMA‐CR?CH₂, was lower than E_a2 for the degradation of PMMA‐H. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

10万m^3原油储罐罐壁板高强钢12MnNiVR的冬季焊接施工

通过对高强钢12MnNiVR焊接性能的分析,提出了高强钢冬季焊接施工带来的问题以及处理办法。得出可靠的焊前预热和焊后保温是确保10万m^3原油储罐冬季焊接施工质量的重要措施。     

用小直径空心纤维薄膜分流过滤葡萄酒

介绍了当今世界上葡萄酒生产过程中,对过滤工序的要求。采用小直径空心纤维薄膜的分流过滤法具有很多优点,在德国占据了很大的市场份额,将在欧洲市场上快速发展起来,具有光明的前景。