氧化淀粉研究的新进展

摘对氧化淀粉及其粘合剂的研究最新进展进行了较全面的综述，尤其对氧化机理、氧化方法和工艺条件等作了详细的阐述，并对其应用进行了展望。     

Epoxidation of allyl alcohol to glycidol using titanium silicalite TS-1: effect of the reaction conditions and catalyst acidity

The epoxidation of allyl alcohol to glycidol using the titanium silicalite TS-1 with hydrogen peroxide as the oxidant is described and discussed in detail. The reaction conditions (alcohol, solvent, temperature) required to obtain 100% selectivity to glycidol are described and this selectivity has been observed at conversions of allyl alcohol of up to 20%. Addition of excess hydrogen peroxide enhances conversion but does not appear to affect selectivity to glycidol deleteriously, whereas addition of hydrogen peroxide over an extended time period is not particularly beneficial. The major side reactions are the oxidation of the alcohol solvent and the ring opening solvolysis of the glycidol that leads to the formation of alkoxy diols. Base treatment of the TS-1 using sodium azide enhances the glycidol selectivity, whereas the incorporation of Brønsted acid sites by addition of aluminium into the framework structure of TS-1 enhances the selectivity to the products of solvolysis ring opening reactions.     

不同氧化剂对玉米淀粉粘合剂质量的影响

本文讨论了ＫＭｎＯ４、Ｈ２Ｏ和ＮａＣｌＯ为氧化剂氧化玉米淀粉的条件以及影响玉米淀粉粘合剂质量的因素。     

氧化剂对聚吡咯复合材料介电性能的影响

为了探究氧化剂对聚吡咯复合材料介电性能的影响,以吡咯为单体,采用原位聚合法制备了聚吡咯涂层复合材料。通过BDS50介电谱仪研究了氧化剂种类和氧化剂物质的量浓度对复合材料介电常数实部、虚部、损耗角正切、表面电阻的影响;采用Quanta200型环境扫描电子显微镜和Instron万能材料试验机研究了聚吡咯涂层复合材料的外观形貌和强度。结果表明:氧化剂种类、氧化剂浓度对聚吡咯涂层复合材料介电常数实部、虚部、损耗角正切、表面电阻影响较大;制备的聚吡咯涂层复合材料既具备良好的介电性能和导电性,又兼具良好的强度.     

苯一步氧化胺化合成苯胺的研究进展

综述了以氧气、晶格氧或过氧化氢为氧化剂,氨气、羟氨或氨水为胺化剂一步合成苯胺的国内外进展情况。以氧气或晶格氧为氧化剂,氨气为胺化剂的苯一步胺化反应,通常需要较高温度和压力;以过氧化氢为氧化剂,氨水为胺化剂的苯一步胺化反应,或以羟氨为胺化剂的苯一步胺化反应,均可在低温常压下发生。最终指出了一步法合成苯胺的研究发展方向。     

茶多酚及其氧化产物清除不同体系产生的活性氧自由基的分光光度法研究

用分光光度法测定了茶多酚及其氧化产物对不同体系产生的活性氧自由基O2· - 和·OH的清除作用。结果表明 :对由光照核黄素体系产生的O2· - ,在试验质量浓度范围 ( 8 3～ 1 67ug mL)内茶多酚及其氧化产物的最大清除率分别为 96 6%和 92 1 %。对由 2 脱氧 D 核糖体系产生的·OH ,在实验质量浓度范围 ( 5～ 80 0ug mL)内茶多酚及其氧化产物的最大清除率分别为83 4%和 88 5%。茶多酚氧化产物 ,SOD粗酶液 ,茶多酚对邻苯三酚自氧化产生的O2· - 均表现出较强的抑制作用 ,抑制率分别为 66 5% ,47 6% ,45 3%。茶多酚及其氧化产物与SOD有显著的协同增效作用 ,但氧化产物的效果强于茶多酚。     

Resistance of LaCl3 to Oxidative Stress Induced by 2, 4-Dichlorophenoxy

Inrecentyears,moreandmoreresearcheshave shownthatrareearthelementshaveeffectsonthere sistibilityofplantstoadverseenvironments[1,2].Di atloffetal.[3]suggestthatlowlevelofLa3 helps plantstowithstanddroughtstressbypromotingroot growth.StudiesbyChenetal.[4]i…     

分光光度法测定循环水及污水中总磷

针对齐鲁分公司循环水、污水样品中总磷酸盐的测定中适宜的氧化剂及用量,选择最佳测定波长和显色条件进行了试验。分析探讨了以往测定循环水、污水中总磷酸盐分析方法用于实际测定时结果产生干扰的原因。改进后的方法操作简便易行、快捷准确,适用于生产中循环水、污水磷含量的监控分析。     

Nanostructured ceria-based catalysts for oxydehydrogenation of ethane with CO2

Nanostructured cerium oxides, pure or doped with CaO, prepared from amorphous acetate precursors obtained by the freeze drying method, exhibit high surface areas and are active and selective catalysts for the oxydehydrogenation of ethane (ODE) using CO₂as an oxidant. The incorporation of Ca into a solid solution in the ceria framework reduces the activity but improves markedly the selectivity to ethene and the efficiency of CO₂. Under reaction conditions, the pure ceria was stable even at 1023 K, while the surface area of the Ca-containing sample decreased markedly. This change was accompanied by a drastic increase in the selectivity to ethene, allowing to obtain yields of ethene up to 22% with 91% selectivity.     

Influencing factors of pyrite leaching in germ-free system

The effect of mineral particle size, pulp potential and category of oxidant on pyrite leaching was studied. The results show that a smaller mineral particle size leads to a higher leaching rate of pyrite, and the optimum result with pyrite leaching rate of 2.92% is obtained when mineral particle size is less than 0.037 mm. The pulp potential reflects the leaching process. The increase of pulp potential can improve pyrite leaching. The leaching rate and velocity of pyrite can be enhanced rapidly by adding strong oxidant. The kind and the method of adding oxidant have important effect on the pyrite leaching. Appropriate concentration of Fe3 can enhance pyrite leaching but the precipitation generated by high concentration of ferric ion covers the surface of pyrites and prevents the leaching process. The leaching rate increases with the constant addition of H2O2.