PCC载体氧化剂的制备及应用研究

制备得到各种有代表性的氯铬酸吡啶(PCC)无机载体氧化试剂,以苯甲醇选择性氧化成苯甲醛为探针反应,考察了载体、反应条件对氧化反应效率的影响,控制各载体氧化剂中PCC的负载量均为1.8 mmol/g。室温下反应,搅拌时间为30 m in,苯甲醇的氧化反应产率为:分子筛65.8%,活性炭75.4%,氧化铝94.6%,硅胶96.9%,相同条件下PCC的产率为65.8%。硅胶是制备负载PCC的优良载体,在载体氧化剂对苯甲醇的氧化反应中,一定范围内增加反应时间和载体加入量都可以提高氧化产率。     

Comparative effects of cobalt carboxylates on the thermo‐oxidative degradation of LDPE films

This article reports the effect of three cobalt carboxylates—cobalt stearate (CoSt₃), cobalt palmitate (CoPal₃), and cobalt laurate (CoLau₃)—on the thermo‐oxidative degradation of low‐density polyethylene (LDPE) films prepared by sheeting process. The carboxylates were blended with LDPE in the concentration range of 0.05–0.2% (w/w). The degradation was monitored by techniques such as FTIR spectroscopy, change in the mechanical properties (tensile strength and elongation at break), viscometry, surface electron microscopy, melt flow index measurements, and apparent density measurements. Studies indicate that films containing these additives are highly susceptible to thermo‐oxidative degradation. Oxygen containing functionalities such as carbonyl and vinyl species are generated on the surface of polyethylene because of thermo‐oxidation, as indicated by FTIR studies. This oxidative process is accelerated in the presence of cobalt carboxylates. The degradation of LDPE was found to increase proportionally with concentration as well as with increasing chain length of the cobalt carboxylate, and follow the order CoSt₃ > CoPal₃ > CoLau₃. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3758–3765, 2007     

The Internal Oxidation of Ternary Alloys I: The Single Oxidation of the Most-Reactive Component Under Low Oxidant Pressures

The internal oxidation of the most-reactive component C of ternary A–B–C alloys by a single oxidant is examined assuming a gas-phase oxidant pressure below the stability of the oxides of the other two components. The precipitation of the most-stable oxide leaves behind a matrix composed of a binary alloy of the two less-reactive components, whose composition affects the solubility and diffusivity of the oxidant within the region of internal oxidation, with an effect on the reaction kinetics. Approximate relations between these properties are proposed and used to predict the kinetics of internal oxidation of C under the assumption of parabolic rate law. The results obtained for the ternary alloys are compared with the behavior of binary A–C and B–C alloys with the same C content. A new important factor in establishing the difference between the internal oxidation in ternary A–B–C alloys and in binary A–C and B–C alloys under a fixed gas-phase oxygen pressure and C content is the ratio between the concentrations of A and B in the bulk ternary alloy.     

过硼酸钠在有机合成中的应用

过硼酸钠（ＳＰＢ）是一种安全、稳定、方便、价廉的理想氧化剂，本文综述了它对各类有机化合物的氧化反应。     

天然栀子黄色素稳定性研究

以吸光度值变化为基础初步探讨氧化剂和抗氧化剂对栀子黄色素溶液稳定性的影响.结果表明,当氧化剂碘酸钾、溴酸钾与栀子黄色素溶液共存时,会引起栀子黄色素的氧化褪色.添加抗氧化剂抗坏血酸、异抗坏血酸钠,能够明显延缓色素的褪色.为在食品体系中更有效地使用天然栀子黄色素提供了依据.     

含砷金铜矿熔炼电尘灰酸性氧化浸出工艺研究

含砷金铜精矿火法熔炼电尘灰是铜冶炼熔炼车间产出的中间产物,成分复杂,较难处理,属于典型危废。以山东某冶炼公司含砷金铜矿熔炼产出的中间产物电尘灰为原料,采用双氧水为氧化剂进行酸性氧化浸出,最佳浸出工艺条件为：双氧水用量120 kg/t、酸性氧化浸出时间2 h、浸出温度80 ℃、酸度60 g/L,铜和砷的浸出率分别达到92.30%、87.50%以上。为铜冶炼企业湿法处理电尘灰提供了一条新途径。     

氧平衡对含KClO4/NH4NO3复合氧化剂气体发生剂燃烧速率的影响

研究了含有复合氧化剂(KClO4、NH4NO3)、以甲基纤维素(MC)和木粉(WP)为燃料的体系在大气压力下的燃烧.结果表明,对于相同氧平衡的KClO4/NH4NO3-MC系列样品,当氧化剂中KClO4相对含量减少时,样品燃速也相应地变小;KClO4/NH4NO3-WP系列样品的燃速变化较为复杂.同系列样品,氧平衡为-15%时,燃速最大.     

铜浸出液的净化除铁研究

研究了氧化－中和沉淀法从铜浸出液中除铁的工艺条件，并介绍了工业实践。     

一次氧化剂O2体积分数对富氧燃烧煤粉着火距离影响的数值模拟

对40 kW同轴射流富氧煤粉燃烧试验系统进行数值模拟,研究了在总体O2体积分数和氧化剂过量系数一定的条件下,不同一次氧化剂O2体积分数对同轴射流富氧燃烧煤粉着火距离的影响,分析了低一次氧化剂O2体积分数下富氧燃烧煤粉着火及火焰稳定性.结果表明:在总体O2体积分数为40％和氧化剂过量系数为1.15的条件下,当一次氧化剂O2体积分数为20.9％时,着火距离较小,为附着火焰;当一次氧化剂O2体积分数减小至14.6％、10.0％和5.5％时,着火距离明显增大,着火延迟,为分离火焰;适当提高二次氧化剂预热温度有利于低一次氧化剂O2体积分数下富氧燃烧的煤粉着火及火焰稳定.