共查询到20条相似文献,搜索用时 125 毫秒
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综述了改变甲苯-硝化异构体分配比例,以及由邻硝基甲苯氧化制邻硝基苯甲酸的各种硝化方法和氧化方法。研究采用PTC-RuO_4-NaClO体系氧化邻硝基甲苯的各种影响因素。当以邻硝基甲苯本身作溶剂,邻硝基苯甲酸的收率是94.5%,次氯酸钠的利用率为82%。对氧化反应历程作了初步探讨. 相似文献
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对氯苯甲醛是一种广泛用于医药、农药和染料的精细化工中间体,发展其绿色合成工艺极具挑战性和重大意义。本文较为系统地综述了催化氧化对氯甲苯为对氯苯甲醛的制备方法,重点阐述了H2O2氧化法、空气/氧气氧化法、电解氧化法和仿生催化氧化法的工艺条件,比较了间接电氧化合成方法中的各种金属媒质,讨论了各种制备方法的优缺点,分析了其相应的合成方法在工业开发上的可行性及存在的问题。此外,简要介绍了利用光催化法选择性氧化对氯甲苯合成对氯苯甲醛的方法。通过对几种合成方法的比较,指出以H2O2和分子氧为氧化剂液相催化氧化对氯甲苯来合成对氯苯甲醛是较为经济、环保的合成方法,电解氧化法和仿生催化氧化法将为对氯苯甲醛制备提供另一条新型技术途径。 相似文献
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以对甲基苯胺、氟硼酸为主要原料,经西曼反应制得对氟甲苯,再经硝酸氧化反应合成对氟苯甲酸。研究了硝酸氧化的工艺,硝酸氧化的最优条件为:硝酸的质量分数为30%,硝酸氧化温度为110℃,反应压力为1.0 MPa,反应时间选择为2.0 h。硝酸氧化的产率为85%。 相似文献
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通过半连续实验考察了对二甲苯(PX)二次氧化过程中的液相氧化,并对该过程进行了模拟计算。设计和进行了包含PX液相氧化、中断反应以及降温二次液相氧化三个阶段的实验;通过动力学实验测定和数据回归确定了基于芳烃氧化自由基链式反应机理的PX液相氧化动力学模型的参数;采用建立的PX液相氧化机理模型对PX分段氧化过程进行了预测。结果表明,对中断反应后的降温二次液相氧化间歇过程,采用第一阶段末期自由基浓度做初值时模型预测值与实验值符合良好;而假设自由基初值浓度为零时,PX液相氧化动力学模型对二次氧化的液相反应预测效果较差,其原因可能是中断降温后的氧化母液中存在过氧基团会使二次液相氧化反应极快地被再引发启动。 相似文献
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使用瓷质阳极氧化工艺在活塞用ZL101A硅-铝合金基材表面制备了阳极氧化膜,并对阳极氧化膜的厚度、表面粗糙度、硬度、成分、表面形貌及耐磨性进行了研究。结果表明:硅-铝合金阳极氧化膜的厚度和表面粗糙度分别为9.7μm和1.74μm。阳极氧化膜主要由铝、氧和钬元素构成,硬度约为3 000 MPa。硅-铝合金阳极氧化膜呈灰白色,主要归因于阳极氧化膜表面的孔洞和树枝状结构。经过瓷质阳极氧化处理后,阳极氧化膜的摩擦因数仅为0.45,有利于提高耐磨性。 相似文献
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Minoru Maeda Kazuo Nakamura Mamoru Yamada 《Journal of the American Ceramic Society》1989,72(3):512-514
Five silicon carbide ceramics with various additives were evaluated for oxidation resistance at 1300°C in flowing dry and wet air. In the dry atmosphere, the oxidation of the five samples was diffusion-controlled, and in wet atmosphere they exhibited a linear relation beween weight gain by oxidation and water vapor content. Water vapor in the atmosphere strongly accelerated oxidation. The influence of oxidation on room-temperature strength was complex, but the samples were not as affected by oxidation. 相似文献
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Fenton氧化技术与其他方法联用在废水处理方面的研究进展 总被引:1,自引:0,他引:1
综述了近些年Fenton氧化技术与其他方法联用在处理难降解有机废水方面的研究进展。重点探讨了吸附-Fenton氧化技术、混凝-Fenton氧化技术、微波-Fenton氧化技术、生物方法 -Fenton氧化技术的特点及其应用研究现状,指出了这些联用技术可改进的地方。此外,展望了联用方法的发展趋势。 相似文献
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Effect of Oxidation on the Room-Temperature Flexural Strength of Reaction-Bonded Silicon Carbides 总被引:1,自引:0,他引:1
Hae-Won Kim Hyoun-Ee Kim Huesup Song Jowoong Ha 《Journal of the American Ceramic Society》1999,82(6):1601-1604
The oxidation behavior of reaction-bonded silicon carbide (RBSC) and the effect of oxidation on the room-temperature flexural strength of RBSC were investigated. Four different types of RBSC, each having various SiC particle-size distributions and free silicon contents, were exposed to air at 1300°C for up to 200 h. Parabolic weight gains, with respect to oxidation time, were observed in all the specimens. The strength of the RBSC increased after oxidation for up to 50 h, because of the blunting of cracks by the silica layer that was formed on the surface. However, with further oxidation, the beneficial role of the oxide layer was negated by the cracks that were newly generated on the surface because of the thermal mismatch between the substrate and the silica layer. The amount of free silicon had a negligible effect on the strength retention of the specimens after the oxidation processes. 相似文献
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铝阳极氧化膜多色彩电解着色工艺 总被引:1,自引:0,他引:1
简述了多色彩电解着色工艺的发展和特点,介绍了2种达到多色化显色的方法:阳极氧化膜底部扩孔处理和调整阳极氧化膜阻挡层。给出了扩孔处理过程中阳极氧化膜横断面的显微结构变化示意图,并给出了“阻挡层调整”实现多色化的工艺参数。描述了多色化阳极氧化膜的性能,并对比了电泳涂漆前后多色彩电解着色样品的颜色。 相似文献
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高级氧化技术是近年来备受人们关注的印染废水处理技术,本文分析了印染废水的基本特征,并就高级氧化技术中的超临界水氧化技术、湿式氧化技术、臭氧氧化技术、电化学氧化技术、Fenton氧化技术、超声波处理技术和光催化氧化技术在印染废水中的应用做了阐述,介绍了各技术的基本原理和应用中优缺点,为高级氧化技术在处理印染废水的实际应用提供了理论依据。 相似文献
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The various metal stearate-catalyzed thermal oxidations of 2,6,10,14,-tetramethylpentadecane (TMPD, a model compound of polypropylene) and the decomposition of TMPD hydroperoxide (TMPD-HPO) were carried out. The results obtained were compared with those of the oxidation of polypropylene reported previously;18 and the initial tion process of the oxidation of the polymer is discussed. The catalytic activity of metastearates in the oxidation of polypropylene differed from that in the oxidation of pure TMPD and was fairly similar to that in the oxidation of TMPD with TMPD-HPO. The more effective the catalyst for the decomposition of TMPD-HPO, the more effective it was for the oxidation of both TMPD with TMPD-HPO and polypropylene. The results apparently indicate that metal catalysts enhance the decomposition of hydroperoxides which presumably contaminate the polymer and form during the oxidation, and also imply that the initiation of the oxidation of polypropylene is primarily affected by the presence of hydroperoxide contamination of the polymer. 相似文献