苯甲醛氧化制备苯甲酸的研究

以氧气为氧化剂,在六水合氯化钴催化剂作用下,催化氧化苯甲醛制备苯甲酸,分别考察了温度、溶剂量、催化剂量、乳化剂量对苯甲酸收率的影响.在苯甲醛:水:乳化剂:六水合氯化钴质量比为75:50:37.5:0.075,反应温度75～80℃,反应时间6 h,氯气流量0.3 L/min下反应,产率在85%以上,用水进行两次重结晶,得率为60%～65%.     

相转移催化氧化法合成苯甲酸

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。     

Selective Oxidation of Acetophenones Bearing Various Functional Groups to Benzoic Acid Derivatives with Molecular Oxygen

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.     

甲苯液相氧化反应过程的动力学研究

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。     

Electrochemical Oxidation of Phenol on Metal‐Impregnated Zeolite Electrodes

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.     

Direct Oxidation of Toluene to Benzoic Acid with Molecular Oxygen over Manganese Oxides

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.     

电化学氧化煤浆特性研究

采用伏安法对六种煤浆的电解氧化特性进行研究,考察了煤种、铁离子溶液催化剂、温度和搅拌速度对氧化电流密度的影响。结果表明,温度、电压和转速的增加可以提高其氧化电流密度,在室温下加入5 mmol Fe3+,可以使神木煤浆的氧化电流密度提高至18.4 m A/cm2。通过XRD分析可知,电解破坏煤的大分子结构。     

Electrochemical Oxidation of Indoles to Access Tryptanthrins at Room Temperature

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.     

木质素的电氧化研究及应用

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。     

碳纤维表面电化学氧化的研究

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。     

电化学高级氧化技术及其水处理应用

电化学高级氧化可以去除一系列有机污染物,是一种极具应用前景的新型水处理技术。本文介绍了电化学高级氧化技术处理废水的研究进展,重点讨论了废水中难降解的酚类化合物、脂肪酸以及全氟有机物的电化学高级氧化去除。最后总结了电化学高级氧化技术发展过程中遇到的主要挑战,并展望了将来的发展方向。     

锆刚玉莫来石—氮化硼复合材料的抗氧化性能研究

推导了锆刚玉莫来石－氮化硼复合材料１０００－１２００℃温度范围内的氧化动力学模型，并用实验数据予以验证。     

2-硝基-4-甲砜基苯甲酸的合成新工艺

研究了甲基磺草酮的重要中间体2-硝基-4-甲砜基苯甲酸的合成新工艺。以2-硝基-4-甲砜基甲苯为原料,双氧水为氧化剂,硫酸为溶剂,硫酸铜为催化剂氧化合成2-硝基-4-甲砜基苯甲酸。通过反应工艺条件优化获得了最佳工艺条件,产品收率可达80.5%,纯度可达98%。该工艺高效、节能、环保,是潜在的传统生产工艺替代方法,具有较好的推广价值。     

Pd与碳纳米管复合材料的制备及对甲酸催化氧化研究

以多壁碳纳米管(MWCNTs)为载体,采用电化学方法可控制备Pd纳米材料和Pd/MWCNTs复合纳米材料,研究对甲酸催化反应中的催化能力和催化效率。循环伏安法(CV)和计时电流法(CA)表明:与相同方法制备的Pd纳米粒子相比,Pd与MWCNTs复合纳米材料对甲酸电化学氧化的正向氧化峰电流密度较高,对甲酸氧化表现出较高的催化活性和催化稳定性。     

Pt-Ni/MWCNTs复合催化剂的制备及电化学性能研究

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。     

Purification of Wet‐Process Phosphoric Acid by Hydrogen Peroxide Oxidation,Activated Carbon Adsorption and Electrooxidation

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.     

Electrochemical test methods for evaluating organic coatings on metals: an update. Part I. Introduction and generalities regarding electrochemical testing of organic coatings

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.     

正丁醛氧化制备正丁酸工艺过程研究

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％。     

邻二甲苯液相氧化剂制邻甲苯甲酸的研究

研究邻二甲苯在钴盐催化剂存在下，用空气进行液相氧化的产物分布和反应机理。