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相转移催化氧化法合成苯甲酸 总被引:1,自引:0,他引:1
以相转移催化氧化法合成苯甲酸,结果表明在酸性介质中以苯作溶剂,反应时间缩短2~3h,产率提高15%以上,MnO2沉淀减少25%。达到了缩短反应时间、提高产率和减少MnO2沉淀的目的。 相似文献
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Ryota Nakamura Yasushi Obora Yasutaka Ishii 《Advanced Synthesis \u0026amp; Catalysis》2009,351(10):1677-1684
Acetophenones substituted by alkyl, alkoxy, acetoxy, and halogen groups were selectively oxidized with molecular oxygen to the corresponding benzoic acids by using the N,N′,N′′‐trihydroxyisocyanuric acid (THICA)/cobalt(II) acetate [Co(OAc)2] and THICA/Co(OAc)2/manganese(II) acetate [Mn(OAc)2]. For example, 4‐methylacetophenone was selectively oxidized with molecular oxygen to 4‐acetylbenzoic acid (85%) by THICA/Co(OAc)2 and to 4‐methylbenzoic acid (93%) by Mn(OAc)2, while terephthalic acid was obtained in 93% with the THICA/Co(OAc)2/Mn(OAc)2 catalytic system. It is interesting that the acetyl group on the aromatic ring is efficiently converted by a very small amount of Mn(OAc)2 to the corresponding carboxylic acid, and that the present method provides a versatile route to acetylbenzoic acids which are difficult to prepare by conventional methods. 相似文献
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甲苯液相氧化反应过程的动力学研究 总被引:5,自引:0,他引:5
在直径Φ48mm 的鼓泡床反应器中对以醋酸钴(CO~(2+))水溶液为催化剂的甲苯液相空气氧化反应动力学进行了研究。结果表明,反应体系的活性时间随催化剂的用量的增大而线性增大,当 Co 含量大于2×10~(-2)%(mass)时,对反应影响较小。甲苯液相空气氧化反应的甲苯消耗动力学分别与甲苯浓度和氧溶解在甲苯中的浓度成一级反应.其宏观动力学活化能约为41 kJ/mol。氧在液相主体消耗的本征动力学活化能为57 kJ/mol,指前因子53.34m~3/(mol·s)。通过 Ha 数和效率因子η对反应动力学控制步骤进行分析,结果表明,Ha 小于0.1,η为0.606~0.728。反应主要发生在液相主体,受动力学控制,但传质仍对反应有影响。 相似文献
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Nanodispersed metallic clusters of platinum, silver and cobalt were incorporated into NaX zeolite cavities by impregnation with acetone solution of corresponding acetylacetonates and solvent evaporation followed by acetylacetonate thermal decomposition. The mixture of modified zeolites and 10 wt % of carbon black, in the form of a thin layer, was pasted onto a glassy carbon surface by Nafion. With such electrode materials, the phenol oxidation in neutral, alkaline and acid solution was studied by cyclovoltammetry. Deactivation of all electrodes in both neutral and alkaline medium was observed, indicating that polymerization reaction might be the main reaction pathway of phenol at higher pH values. Formation of quinine‐type structures was obtained during electro‐oxidation at lower pH values, being more significant in acidic solutions. 相似文献
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Direct Oxidation of Toluene to Benzoic Acid with Molecular Oxygen over Manganese Oxides 总被引:2,自引:0,他引:2
Xiaoqiang Li Jie Xu Feng Wang Jin Gao Lipeng Zhou Guanyu Yang 《Catalysis Letters》2006,108(3-4):137-140
Manganese oxides, which are easily prepared, simple to use and capable of being recycled, have been employed as catalyst in
the selective oxidation of toluene to benzoic acid for the first time. Molecular oxygen was used as oxidant under additive-
and solvent-free conditions. As a result, 39% conversion of toluene and 93% selectivity of benzoic acid were achieved. 相似文献
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Ziyi Guo Yi Liu Hang Li Jiaping Wu Meihua Xie Jitan Zhang 《Advanced Synthesis \u0026amp; Catalysis》2024,366(2):225-231
An electrooxidative reconstruction of the indole core under ambient conditions is reported, resulting in the construction of tryptanthrins. This electrochemical strategy simplifies molecular skeleton-hopping by employing commercially available NH-indole feedstock as the starting materials. Furthermore, the synthetic value of this skeletal reconstruction was demonstrated by divergent further transformations. A preliminary mechanistic investigation involving control experiments and cyclovoltammetric studies showed the indispensability of electricity, as well as the importance of oxygen and TEMPO, thereby revealing a possible reaction pathway. 相似文献
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木质素的电氧化研究及应用 总被引:2,自引:0,他引:2
综述了木质素的电氧化机理研究及其应用。木质素的电氧化有两种机理 ,一种是失去两个电子产生苯氧正离子 ,然后苯氧正离子与水或甲醇反应 ;而在碱性介质中 ,倾向于发生单电子转移 ,产生苯酚自由基 ,然后形成碳碳双键。在一定条件下 ,电氧化会导致苯环的减少和羧基的增加 ,具有脱甲氧基的作用。木质素的电氧化可应用于木质素功能化、木质素降解、纸浆的漂白和废水漂白。 相似文献
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碳纤维表面电化学氧化的研究 总被引:13,自引:2,他引:11
主要采用电化学氧化法对聚丙烯腈(PAN)基碳纤维进行连续氧化处理,利用扫描电子显微镜(SEM)、X射线光电子能谱(XPS)和动态力学热分析(DMTA)对碳纤维表面处理效果进行了研究。SEM表面形貌研究结果表明,碳纤维经电化学氧化处理后,其表面的粗糙度和比表面积增大。XPS表面化学分析表明,经电化学氧化处理后的碳纤维表面羟基含量提高55%,活性碳原子数增加18%。DMTA谱图表明经电化学氧化处理的碳纤维增强树脂基复合材料(CFRP)其玻璃化温度(Tg)提高5℃、损耗角正切(tanδ)较未处理的降低30%。定量计算出的界面黏结参数A和α与CHRP的层间剪切强度(ILSS)所反映的碳纤维与树脂间界面黏结效果是一致的。研究结果表明,采用适当的处理条件可使CFRP的ILSS提高20%以上。 相似文献
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采用溶液还原法将铂镍负载于多壁碳纳米管(MWCNTs)制备Pt-Ni/MWCNTs复合催化剂。利用透射电子显微镜(TEM)、 X射线衍射仪(XRD)对复合催化剂进行结构表征,结果表明,铂镍均匀负载到碳纳米管上,Pt-Ni粒子粒径约为2 nm。XRD分析结果表明,复合催化剂是以Pt晶格为基础的固溶体结构。采用循环伏安法和计时电流法在碱性条件下对修饰电极进行电化学性能研究,结果表明,Pt-Ni/MWCNTs可直接催化葡萄糖氧化,催化剂对葡萄糖的灵敏度为571.68 μA•mmol/(L•cm2),线性范围1.0×10-5-8.2×10-3 mol/L (R=0.9994),电极对葡萄糖的最低检测限为0.5 μmol/L(S/N=3),该电极对葡萄糖有良好的电催化氧化性能,且选择性和重现性好,可有效避免抗坏血酸、尿酸和多巴胺的干扰。 相似文献
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In this work, three technologies are studied for the purification of phosphoric acid produced by the wet process: chemical oxidation with hydrogen peroxide, adsorption onto activated carbon, and electrochemical oxidation by boron‐doped diamond anodes. The treatment of wet‐process phosphoric acid by chemical oxidation with H2O2 as oxidizing agent can remove 75 % of the initial TOC as maximum, indicating that this wet‐process phosphoric acid contains an important amount of organics that cannot be oxidized by hydrogen peroxide under the operation conditions used. High temperatures and hydrogen peroxide/TOC ratios close to 150 g H2O2/g TOC allow obtaining the best chemical oxidation results. The adsorption onto activated carbon can remove between 40 and 60 % of the initial TOC as maximum. Adsorption times of 2 hours and activated carbon/WPA ratios close to 12 g AC/Kg WTP assure both steady state and maximum adsorption of organics. The electrochemical process is the only technique by which complete mineralization of WPA organics can be achieved. Operating at 60 mA cm–2 and at room temperature, high current efficiencies are achieved which only seem to decrease by mass transport limitations. 相似文献
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John N. Murray 《Progress in Organic Coatings》1997,30(4):225-233
The status of evaluating organic coated metals utilizing electrochemical means was reviewed for the period of 1988–1994. The general improvements in the overall technology are presented in three sections. Part I covers the test cell configurations, changes in testing approaches and a brief survey of measurement equipment. Part II presents the test methods involving a single test parameter such as the panel potential relative to a reference electrode, electrochemical voltage and/or current noise, as well as the dc resistance of the coating on the metal substrate. Multiple test parameter measurements such as potentiodynamic curves and electrochemical impedance spectroscopy are covered in Part III. Although the majority of data were taken from the literature, some supplementary data are included from NSWCCD studies. 相似文献
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正丁醛氧化制备正丁酸工艺过程研究 总被引:2,自引:0,他引:2
在反应温度50-60℃,氧醛摩尔比0.75-0.875,催化剂与正丁醛的质量比0.1%-0.2%,反应时间为3h左右的优化的工艺条件下进行了正丁醛氧化制正丁酸的研究。结果表明:在优化的工艺条件下正丁醛的转化率在99.5%以上;正丁酸的选择性超过了95.0%。 相似文献
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