Silicate-based polymer-nanocomposite membranes for polymer electrolyte membrane fuel cells

Proton-exchange membrane fuel cells have emerged as a promising emission free technology to fulfill the existing power requirements of the 21st century. Nafion^® is the most widely accepted and commercialized membrane to date and possesses excellent electrochemical properties below 80 °C, under highly humidified conditions. However, a decrease in the proton conductivity of Nafion^® above 80 °C and lower humidity along with high membrane cost has prompted the development of new membranes and techniques. Addition of inorganic fillers, especially silicate-based nanomaterials, to the polymer membrane was utilized to partially overcome the aforementioned limitations. This is because of the lower cost, easy availability, high hydrophilicity and higher thermal stability of the inorganic silicates. Addition of silicates to the polymer membrane has also improved the mechanical, thermal and barrier properties, along with water uptake of the composite membranes, resulting in superior performance at higher temperature compared to that of the virgin membrane. However, the degrees of dispersion and interaction between the organic polymer and inorganic silicates play vital roles in improving the key properties of the membranes. Hence, different techniques and solvent media were used to improve the degrees of nanofiller dispersion and the physico-chemical properties of the membranes. This review focuses mainly on the techniques of silicate-based nanocomposite fabrication and the resulting impact on the membrane properties.     

N,O-双三甲基硅基乙酰胺的合成进展

简述了N,O-双三甲基硅基乙酰胺的应用,论述了国内外合成工艺路线,并对其优缺点进行讨论。     

奈非西坦的合成研究

奈非西坦是新研制的一种对阿尔茨海默氏病和脑血管后遗症有良好的临床治疗价值的药物。对奈非西坦的各种合成方法进行了总结,分析了各路线的优缺点,并对奈非西坦的药理学内容做了概述。     

绿色合成AMA反应中纳米Pd/C催化剂的失活和再生

在2-硝基-4-乙酰胺基苯甲醚(NMA)催化加氢合成2-氨基-4-乙酰胺基苯甲醚(AMA)反应中,规整纳米Pd/C催化剂表现出很好的催化活性和选择性。但Pd/C催化剂在反应的套用过程中表现出反应活性逐渐降低。通过XRD、BET、EDS、XPS等物性表征以及Na2S滴定法和原子吸收法测定Pd含量的研究表明,钯微晶的长大、钯流失、催化剂中毒等不是引起Pd/C催化剂失活的主要原因,而Pd/C催化剂表面金属钯活性位在反应后被2-氨基-4-乙酰胺基苯甲醚产物等有机物覆盖可能是导致其性能逐渐降低的关键。使用酸洗法可以去除反应后Pd/C催化剂表面覆盖的2-氨基-4-乙酰胺基苯甲醚等有机物,释放金属钯活性位,实现Pd/C催化剂的性能有较大程度的恢复;而其他方法对Pd/C催化剂活性恢复的效果不明显。     

流加操作与稀释添加耦合辅助高浓度变性蛋白质复性动力学

研究了流加操作与稀释添加耦合辅助高浓度变性还原溶菌酶的复性,建立了相关的过程动力学模型.利用三态复性的过程模型对实验数据进行了拟合,获得了较好的拟合效果.利用模型分析了复性过程的动力学特性,结果表明,两者耦合可在较低的盐酸胍浓度(1 mol•L^-1)存在下使较高浓度的（5 mg•ml^-1）变性溶菌酶获得80%以上的复性收率;并且发现添加剂乙酰胺的辅助复性作用与盐酸胍相同,降低盐酸胍浓度,适当提高乙酰胺浓度即可使聚集体生成速率常数最小,酶的复性收率最大;但甘油与盐酸胍具有协同作用,只有在适当的盐酸胍浓度下添加甘油才可获得理想的复性效果.     

N,N（二甲庚基）乙酰胺萃取钯的热力学

本文研究了N,N(二甲庚基)乙酰胺(N503)从盐酸体系中萃取钯的热力学。通过考察萃取剂浓度和温度对钯(Ⅱ)分配比的影响,测得该萃取反应的表观平衡常数K、焓变ΔH、自由能变ΔG和熵变ΔS。     

乙酰胺的合成研究

乙酰胺主要应用于有机溶剂、增塑剂、稳定剂及化妆品中的抗酸剂,目前在国内的主要用途是作为青霉素头孢菌素中间体7-氨基-去甲氧基头孢霉烷酸的原料。合成乙酰胺共有6种路线,文中对其中的一种合成工艺进行了研究,并且该种合成工艺已建成200t/a的生产装置。经检测,产品完全可用于头孢菌素的生产,产品利税率达到41.2％。     

添加剂对HMX重结晶晶体形貌的影响

通过模拟计算与试验相结合的方法,研究了添加剂乙酰胺、丙烯酰胺、乙胺水溶液对重结晶HMX晶体形貌控制的影响.结果表明,3种添加剂对HMX重结晶晶体形貌影响的大小顺序为:乙酰胺＞丙烯酰胺＞乙胺,乙酰胺使晶体偏离球形化,丙烯酰胺具有使晶体向着球形化发展的趋势,由于乙胺与HMX晶面的附着能较小,乙胺对HMX重结晶晶体形貌改变不...     

1,3,4-噻二唑取代的N-(噻吩并吡啶)乙酰胺类化合物的合成及生物活性研究

以2-氯-3-氰基吡啶为起始原料,设计并合成了一系列1,3,4-噻二唑取代的N-(噻吩并吡啶)乙酰胺类新化合物。所有化合物或中间体结构经1H NMR、13C NMR、IR和MS确认。初步生物活性测试结果表明,部分化合物具有较高的抑菌或杀虫活性。     

Attraction of Female and Male Bactrocera papayae to Conspecific Males Fed with Methyl Eugenol and Attraction of Females to Male Sex Pheromone Components

The attraction of female and male Bactrocera papayae to conspecific males fed with methyl eugenol (ME) and female attraction to male synthetic sex pheromone, trans-coniferyl alcohol (CF), were evaluated in a wind tunnel. Earlier and greater attraction were exhibited by both females and males to ME-fed than to non-ME-fed males as dusk approaches. Males increased their precopulatory behavior (i.e., wing fanning and mounting) during the period of higher attractancy. These data confirm that the consumption of ME enhances the mating competitiveness of males and suggest that ME also functions as a precursor to the male sex and aggregation pheromones. Three phenylpropanoid compounds biosynthesized from ME, coniferyl alcohol, 2-allyl-4,5-dimethoxyphenol, and 3,4-dimethoxycinnamyl alcohol, were detected in male rectal gland along with an endogenous rectal compound, N-(3-methylbutyl) acetamide. When offered singly to the females, coniferyl alcohol was found to be most attractive.