铈离子清除超氧物自由在的机理

以光辐照核黄素作为超氧物自由基（Ｏ２）源，研究了Ｃｅ＾３＋、Ｃｅ＾４＋对硝基四氮唑蓝（ＮＢＴ）还原、羟胺化的抑制作用和铈离子存在时Ｈ２Ｏ２含量、核黄素光分解、溶解氧消耗和变化以及铈离子价态的变化。从而得知，铈离子可清除Ｏ２，其机理为：Ｃｅ＾３＋供给Ｏ２电子氧化为Ｃｅ＾４＋、Ｏ２还原为Ｈ２Ｏ２；Ｃｅ＾４＋从Ｏ２获得电子还原为Ｃｅ＾３＋，Ｏ２氧化为Ｏ２。所以微量的铈离子可清除大量的Ｏ２。     

金属键有机化合物的研究—非对称型η^5—取代环戊二烯…

通过η＾５－Ｒ＾１Ｃ５Ｈ４（ＣＯ）３ＭＨａ与η＾５－Ｒ＾２Ｃ５Ｈ４（ＣＯ）２ＭＮａ（Ｍ＝Ｍｏ，Ｗ）以及η＾５－Ｒ＾１Ｃ５Ｈ４（ＣＯ）３ＭｏＮａ与η＾５－Ｒ＾２Ｃ５Ｈ４（ＣＯ）３ＷＮａ在Ｆｅ２（ＳＯ４）３醋酸水溶液作用下的交叉氧化偶联反应，合成了７个新的非对称型金属单键化合物η＾５－Ｒ＾１Ｃ５Ｈ４（ＣＯ）３Ｍｏ－Ｍｏ（ＣＯ）３Ｃ５Ｈ４Ｒ＾２－η＾５（Ｒ＾１，Ｒ＾２：Ｃ（Ｏ）Ｍｅ，ＣＯ２Ｅｔ），η＾５     

苄醇的选择性间接电氧化

以Ｃｅ￣（４＋）／Ｃｅ￣（３＋）为氧化还原体系，以硫酸为支持电解质，采用槽内法研究了苄醇的选择性间接电氧化。得出最佳电解条件：电流密度，０．１Ａ／２０ｃｍ￣２；亚铈与反应物当量比，１：６；硫酸浓度，３ｍｏｌ／Ｌ；通过电量，２Ｆ／ｍｏｌ（Ｆ为理论电量）。在最佳电解条件下，反应产物为苯甲醛，产率高达９６％，不发生深度氧化。阳极液循环１０次以上，对反应产率无影响。反应中Ｃｅ￣（４＋）只起电子传递作用，反应仅消耗电能，因此此法十分经济，且无污染。     

ABO3,A2BO4型复合氧化物催化剂用于CO,CH4,NH3完全氧化的比较

本文探讨了ＣＯ，ＣＨ４和ＮＨ３在ＬａＮｉＯ３，Ｌａ２ＮｉＯ４和ＬａＳｒＮｉＯ４三个催化剂上的氧化行为，并得出结论：对于ＣＯ氧化，关键步骤在于ＣＯ在催化剂表面上的络合活化。Ｎｉ＾３＋含量越高，越利于ＣＯ的络合活化。对于氨氧化，催化反应遵循氧化－还原机理。Ｎｉ＾３＋是主要的活性离子，晶格氧是主要活性氧种。对于ＣＨ４氧化，催化机理较复杂，只是发现Ａ２ＢＯ４型氧化物（Ｌａ２ＮｉＯ４，ＬａＳｒＮｉＯ４）比Ａ     

全氟磺酸膜的离子选择性

研究了Ｎａｆｉｏｎ１１７膜（一种全氟磺酸膜）对阳离子的选择性,测定了含Ｋ＾＋,Ｎｉ＾２＋及Ｆｅ＾３＋的Ｎａｆｉｏｎ１１７膜的离子选择性系数,实验发现含Ｈ＾＋,Ｋ＾＋,Ｐｂ＾２＋,Ｎｉ＾２＋,Ｃｏ＾２＋,Ｆｅ＾３＋等离子的膜都能较好符合Ｎｅｒｎｓｔ响应。膜对一价离子的选择性优于二价及三价离子。     

PTFE—乙醚柱反相萃取层析连续分离和测定镓（Ⅲ）铟（Ⅲ）的研究

研究了在抗坏血酸存在下的６ｍｏｌ／Ｌ ＨＢｒ介质作流动相，以ＰＴＦＥ（聚四氟乙烯）负载的乙醚作固定相，反相萃取层析使微量Ｇａ（Ⅲ），Ｉｎ（Ⅲ）与Ｆｅ＾３＋、Ｔｌ＾３＋、Ｍｏ＾６＋、Ａｕ＾３＋、Ｔｉ＾４＋、Ｂｉ＾３＋、Ａｌ＾３＋、Ｍｇ＾２＋、Ｃａ＾２＋、Ｎｉ＾２＋、Ｃｏ＾２＋、Ｃｄ＾２＋、Ｚｎ＾２＋、Ｐｂ＾２＋、Ｃｕ＾２＋等多种离子分离。留于柱上的铟、镓分别用ＨＣｌ（４ｍｏｌ／Ｌ）－Ｈ２Ｏ２（３％）     

N-溴代丁二酰亚胺滴定法测定铁矿石中铁

铁矿石经盐酸溶解后,用Ｈ２Ｏ２氧化,使Ｆｅ＾２＋氧化成Ｆｅ＾３＋。加入过量的ＶＣ还原Ｆｅ＾３＋,剩余ＶＣ用ＮＢＳＭ滴定。方便简便,快速,终点敏锐,精了,准确度高,ＲＳＤ≤０．３％,相对误差〈０．４％,并可选择性地滴定矿石中的三价铁。     

碘量法测定冶金物料中铁

系统地研究了Ｆｅ＾３＋与Ｉ＾－定量反应的条件，共存离子的干扰及消除方法，在ＨＣｌ和ＫＩ存在下，Ｆｅ＾３＋与Ｉ＾－定量反应，Ｃｕ＾２＋，ＡｓＯ４＾３－，ＶＯ２＾＋，等定量干扰，使用ＮａＦ或Ｈ３ＰＯ４制备参比液可抵消干扰。可不经分离直接测定大部分冶金物料中的高含量铁。     

荧光法测定Fenton反应产生的羟自由基

建立了一种新的测定Ｆｅｎｔｏｎ反应产生羟自由基·ＯＨ的方法。Ｃｅ＾３＋在稀硫酸中能产生特征荧光，其最大激发波长和发射波长分别为２８０ｎｍ和３６０ｎｍ。Ｆｅｎｔｏｎ反应产生的·ＯＨ能将Ｃｅ＾３＋氧化成Ｃｅ＾４＋，用荧光法测定Ｃｅ＾３＋的荧光强度变化即可间接测定羟自由基的产生量。通过对测定条件的研究，得到最佳实验条件，。结果表明，该方法稳定性好、操作简便、测定快速，可作为一种简便的筛选抗氧化剂的方法。     

铁基高温变换催化剂制备的穆斯堡尔谱研究Ⅰ.铁氧化物前驱态的相变过程

用穆斯堡尔谱及ＸＲＤ技术对不同铁氧化物前驱态的相变过程进行了，ＦｅＣＯ３沉淀在空气中老化时被氧化分解生成ＦｅＯ（ＯＨ），经干燥、煅烧后合部转化为ａ－Ｆｅ２Ｏ３。（Ｆｅ（ＯＨ）２沉淀物在空气中老化时则转化为Ｆｅ３Ｏ４．２Ｈ２Ｏ和ＦｅＯＯＨ，两者的相对含量受Ｆｅ＾２＋的迁移速率和Ｆｅ（ＯＨ）２的氧化速度的影响。     

IBX/n-Bu4NBr/CH2Cl2-H2O: a new mild system for selective oxidation of secondary alcohols

A new alternative system for the chemoselective oxidation of secondary hydroxyl group to ketone with IBX/n-Bu₄NBr in CH₂Cl₂-H₂O has been developed. Under the reaction conditions, the secondary hydroxyl group was highly chemoselectively oxidized to the corresponding ketone, in moderate to good yields at rt, in the presence of primary hydroxyl group within the same molecule.     

A metal-free approach to access ketones,amides, and nitriles employing TBAI/TBHP oxidative system in water

Hydrocarbons, benzylamines, and heteroaromatic-bearing amines have been efficiently employed as substrates in allylic and benzylic oxidations via C(sp3)–H bond activation by TBAI/TBHP in water. This operationally simple method allows access to ketones, nitriles, and amides in moderate to high yields and a regio- and chemoselective late-stage functionalization.     

甲烷直接氧化制甲醇研究进展概述

目前,天然气转化为高附加值化工产品的应用越来越受到人们关注.甲烷作为天然气的主要成分,其转化和应用是天然气化工领域的重要研究方向.而甲烷直接氧化制甲醇长久以来一直是研究重点.甲烷直接氧化制甲醇与传统的甲烷二步法间接转化相比,有节能和工艺简化的突出特点.然而,甲醇直接氧化制甲醇过程所面临的主要问题有：(1)甲烷分子的活化能很高,需要苛刻的操作条件才能活化参与反应;(2)反应进行的程度难以控制,生成的甲醇会进一步被氧化生成较多副产物,大大降低甲醇收率.因此,高效活化甲烷分子和抑制甲醇深度氧化是促进该过程工业化的重要研究内容.本文主要论述了非均相、气相均相和液相体系中甲烷直接氧化制甲醇的研究进展.在甲烷非均相氧化过程中,采用过渡金属氧化物作为催化剂在高温条件下催化甲烷部分氧化反应,其中,钼系和铁系催化剂的研究最为广泛.研究表明, MoO3可作为催化剂的主要活性组分,尤以 MoO3/Ga2O3催化剂性能最好,得到甲醇收率最高.在铁系催化剂中, Fe-ZSM-5 催化反应的甲醇选择性和收率都相对较高;但是每次反应后催化剂都需要重新活化,这种间歇性操作会增加成本,不利于工业化应用.总之,甲烷的非均相氧化过程存在易形成金属聚集体、催化剂选择性低以及甲醇收率低(5%)等问题,需要深入系统地研究解决.然而,与非均相氧化过程相比,操作较为简单的甲烷气相均相氧化作为目前最有工业前景的过程受到越来越多关注.在此过程中,影响反应的主要因素有反应器、反应条件(反应压力、反应温度和反应时间等)以及添加的介质等.反应器的特殊设计需要考虑的方面有反应产物的分离与转移、反应热的移除以有效提高甲烷的转化率,比如膜反应器对物质的分离作用.反应压力对反应过程的影响较为复杂.基于动力学因素,提高反应压力可以较大幅度地增加甲醇收率,同时最佳反应温度降低,但是,当压力高于8.0 MPa时,设备成本消耗大幅增加.另外,研究表明,进料中加入 NOx作为添加介质可以提高甲烷转化率和甲醇选择性,同时降低初始反应温度.与前两个氧化体系相比,液相均匀氧化过程能够获得较高的甲烷转化率与甲醇选择性.但是液相体系中强腐蚀性介质的使用增加了设备成本,阻碍了该过程工业化的应用进程.因此,促进液相体系工业化的关键就是开发绿色高效的催化剂.     

Synthesis and analysis of aminochromes by HPLC-photodiode array. Adrenochrome evaluation in rat blood

The catecholamine oxidation process induces cardiotoxicity and neurotoxicity. Catecholamines can oxidize to aminochromes through autoxidation or by enzymatic or non-enzymatic catalysis. Although some toxic effects seem to be related to the formation of aminochromes there is still scarce information concerning the identification and evaluation of these compounds in in vivo models. In this study five catecholamines were oxidized to their respective aminochromes: adrenaline/adrenochrome; noradrenaline/noradrenochrome; dopa/dopachrome; dopamine/dopaminochrome; and isoproterenol/isoprenochrome. The evaluation of the catecholamines oxidation profile was performed by HPLC with photodiode array detection and using either enzymatic (tyrosinase) or non-enzymatic [Ag(2)O, CuSO(4), NaIO(4) and K(3)Fe(CN)(6)] catalytic systems. The NaIO(4) was found to be the most efficient oxidant of catecholamines. An isocratic reverse-phase HPLC method was developed to analyse each pair of catecholamine-aminochrome. The analytical system was then applied to the detection of adrenochrome in rat blood at 490 nm. Thus, adrenochrome was administered i.p. to rats and its concentration in whole blood was monitored after 5, 15 and 25 min. Blood treatment for adrenochrome evaluation consists of an acidification for protein precipitation followed by a rapid neutralization. The results showed a rapid decrease of adrenochrome concentration in blood after its administration. The adrenochrome present in blood was characterized by UV and tandem mass spectrometry.     

Baeyer-Villiger oxidation of ketones with hydrogen peroxide catalyzed by Sn-palygorskite

Palygorskite-supported Sn complexes were prepared by a simple procedure. Cyclic ketones and acyclic ketones were oxidized by hydrogen peroxide in a reaction catalyzed by palygorskite-supported Sn complexes, affording corresponding lactones or esters with selectivity for the product of 90-100%. The catalysts can be recycled for several times without significant decline in catalytic activity.     

Ni催化剂上甲烷部分氧化制合成气反应性能与碳物种的关系

In the partial oxidation of methane (POM) to syngas, carbon deposition on the catalyst causing catalyst deactivation or reactor plugging was reported[1～3]. Our previous work showed that methane dissociation on metallic sites to H2 and NixC is an initial step of POM over Ni/Al2O3[4]. If NixC can not be consumed immediately after its formation, it has a tendency to dissolve into the nickel crystal to form carbon whiskers. The bulk carbon and carbon whiskers are more difficult to be oxidized than NixC. Therefore, prohibiting the transformation of NixC to bulk carbon and carbon whiskers can depress the formation of carbon deposition effectively.     

NHPI, CoSPc和TBAB催化的乙苯液-液非均相绿色氧化反应研究

以水为催化剂溶剂与原料乙苯组成液-液非均相体系,以NHPI结合CoSPc组成催化体系,在TBAB为相转移催化剂的作用下,对乙苯的氧化反应条件进行了研究.研究发现乙苯在该催化体系中的最佳氧化条件依次是:水油体积比为3∶1;n(TBAB)∶n(乙苯)=1∶40;n(NHPI)∶n(乙苯)=1∶10,n(NHPI)∶n(CoSPc)=24∶1,反应温度110℃,氧气压力0.75 MPa,搅拌速率350 rpm,反应时间0.5 h.在最佳反应条件下乙苯转化率为60.6%,苯乙酮的选择性为95.2%,1-苯乙醇的选择性为4.5%,产物总选择性达到了99.7%.在此基础上延长反应时间并不能提高乙苯的转化率,苯乙酮的选择性也会下降,研究发现NHPI的分解是乙苯转化率不随反应时间的延长而提高的原因,而苯乙酮的过度氧化为苯甲酸是产物选择性下降的原因.     

Pulse radiolysis study of one-electron oxidation of thionine in aqueous solutions

One-electron oxidation of thionine has been studied using specific oxidizing radicals such as Cl⁻Tl(II) and N₃ generated by pulse radiolysis of aqueous solutions. The semioxidized thionine exhibited threepK’s indicating four conjugate acid-base forms. N₃ radicals were found to be less efficient in oxidizing thionine as compared to Cl ₂ ⁻ , Tl²⁺ and Tl(OH)⁺. The rate constants for electron abstraction from thionine by Cl ₂ ⁻ , Tl²⁺, Tl(OH)⁺, Tl(OH)₂ and N₃ were evaluated. The spectra of different protonated forms of semioxidized thionine and the extinction coefficients at λ_max are presented. Reaction of OH radicals with thionine gave transient products whose spectra and acid-base properties were different from those of semioxidized thionine. The rate constant for formation of the product transient agrees well with competition kinetic value for reaction of OH with thionine reported earlier.     

Lysozyme oxidation by singlet molecular oxygen: Peptide characterization using [18O]‐labeling oxygen and nLC‐MS/MS

Singlet molecular oxygen (¹O₂) is generated in biological systems and reacts with different biomolecules. Proteins are a major target for ¹O₂, and His, Tyr, Met, Cys, and Trp are oxidized at physiological pH. In the present study, the modification of lysozyme protein by ¹O₂ was investigated using mass spectrometry approaches. The experimental findings showed methionine, histidine, and tryptophan oxidation. The experiments were achieved using [¹⁸O]‐labeled ¹O₂ released from thermolabile endoperoxides in association with nano‐scale liquid chromatography coupled to electrospray ionization mass spectrometry. The structural characterization by nLC‐MS/MS of the amino acids in the tryptic peptides of the proteins showed addition of [¹⁸O]‐labeling atoms in different amino acids.     

Pd-Mn/Stainless Steel Wire Mesh Catalyst for Catalytic Oxidation of Toluene,Acetone and Ethyl Acetate

A new 0.1%Pd‐6%Mn/stainless steel wire mesh catalyst was prepared and used for volatile organic compounds (VOC) elimination. The supported palladium and manganese catalyst over the stainless steel wire mesh was prepared by using an impregnation method. When an anodic oxidation technology was employed, an anodic oxidation membrane appeared on the stainless steel wire mesh. On the 0.1%Pd‐6%Mn/stainless steel wire mesh catalyst calcined at 500°C, the total oxidation of toluene, acetone and ethyl acetate was respectively at 260, 220 and 320°C. The activity could be stable for over 700 h for toluene oxidation. The scanning electron microscopy (SEM) investigation of the Pd‐Mn/stainless steel wire mesh catalyst shows that the presence of anodic oxidation membrane on the support surface is important for better dispersion of active phases.