Bistriphenylsilanol-Assisted Oxidation Catalyzed by Chromium(VI) Oxide of Activated Trimethylsilyl Ethers with tert-Butyl Hydroperoxide

Secondary benzylic or allylic trimethylsilyl ethers are oxidized at room temperature to the corresponding ketones in good yields using aqueous 70% t-BuOOH and catalytic amounts of a mixture of Ph₃SiOH and CrO₃.     

二氧化碳-氧化环己烯的共聚反应

由CO2 -氧化环己烯 (CHO)配位催化共聚制得高Tg 的脂肪族聚环己基撑碳酸酯 ,并用IR、NMR和DSC等进行了表征 ,用TG对聚合物的热稳定性进行了分析。加入异氰酸苯酯有提高产物特性粘数的作用。     

常压下Pt-Bi双金属催化剂上甘油选择性氧化

制备了一系列活性碳(AC)负载的Pt-Bi双金属催化剂,考察了催化剂中Bi含量对其催化甘油选择性氧化反应性能的影响.结果表明,适量Bi的添加可以改善催化剂中Pt的氧化还原性能,从而有利于催化剂活性的提高和二羟基丙酮(DIHA)产物的生成.当Bi的含量为5%时,该催化剂的活性最高,甘油转化率和DIHA选择性分别达到91.5%和49.0%.表征结果显示,Pt-Bi颗粒的平均粒径为3.8nm,且高度分散在催化剂表面,这是该催化剂具有较高活性的主要原因.     

二氧化碳-氧化苯乙烯的共聚反应

由ＣＯ２－氧化苯乙烯（ＳｔＯ）配位催化共聚制得脂肪族聚碳酸苯亚乙酯,并用 ＩＲ、１ＨＮＭＲ和 ＤＳＣ等进行表征,用 ＴＧ对聚合物的热稳定性进行了分析。     

Oxidations involving silver—IX : Oxidation of primary amines by silver(II) picolinate.

A re-examination of the oxidation of primary amines of the type R·CH₂NH₂ by silver(II) picolinate reveals that the major product is usually the nitrile RCN, rather than the aldehyde RCHO, as had been reported previously.⁴     

甲缩醛氧化制浓甲醛用Fe－Mo氧化物催化剂的研究

制备了甲缩醛氧化制浓甲醛的金属氧化物催化剂。以管式反应器和色谱分析联用装置考察了铁－钼氧化物体系及添加第三组分铬和铋的催化剂的活性。结果表明，具有高活性催化剂的Ｍｏ／Ｆｅ最佳原子比为２．０～２．６，反应温度＞２９０℃，所得甲缩醛转化率＞９８％，甲醛选择性可达１００％。     

Oxidation of alcohols with oxoperoxobis(N-phenylbenzohydroxamato)molybdenum(VI)

The title complex oxidizes primary and secondary alcohols to the corresponding carbonyl compounds. Stereoselective epoxidation of allylic alcohols is also described.     

高铁酸盐电化学合成的研究

采用电化学阳极氧化法制备高铁酸盐,研究制备条件对电解产率的影响.结果表明,灰口铸铁是较为理想的阳极材料.在以14mol·dm-3NaOH作电解液、20℃和电流密度4.54mA·cm-2条件下电解1h,得最高电流效率为68.5%,优于使用KOH作电解液.     

Selective Oxidation of Betulin by Cr(VI) Reagents

Oxidation of betulin by pyridinium dichromate, pyridinium chlorochromate, and K₂Cr₂O₇ -H₂SO₄ in the presence of tetrabutylammonium bromide was studied. Products of regioselective C-3, C-28-, and exhaustive oxidation, 28-hydroxylup-20(29)-3-one, 3-hydroxy- and 3-oxolup-20(29)-en-28-al were obtained.     

Methane Activation Mediated by a Series of Cerium–Vanadium Bimetallic Oxide Cluster Cations: Tuning Reactivity by Doping

The reactions of cerium–vanadium cluster cations Ce_xV_yO_z⁺ with CH₄ are investigated by time‐of‐flight mass spectrometry and density functional theory calculations. (CeO₂)_m(V₂O₅)_n⁺ clusters (m=1,2, n=1–5; m=3, n=1–4) with dimensions up to nanosize can abstract one hydrogen atom from CH₄. The theoretical study indicates that there are two types of active species in (CeO₂)_m(V₂O₅)_n⁺, V[(O_t)₂]^. and [(O_b)₂CeO_t]^. (O_t and O_b represent terminal and bridging oxygen atoms, respectively); the former is less reactive than the latter. The experimentally observed size‐dependent reactivities can be rationalized by considering the different active species and mechanisms. Interestingly, the reactivity of the (CeO₂)_m(V₂O₅)_n⁺ clusters falls between those of (CeO₂)_2–4⁺ and (V₂O₅)_1–5⁺ in terms of C?H bond activation, thus the nature of the active species and the cluster reactivity can be effectively tuned by doping.     

Oxidation of alcohol by lipopathic Cr(VI): a mechanistic study

The oxidation kinetics of various aliphatic primary and secondary alcohols having varied hydrocarbon chain length were studied using cetyltrimethylammonium dichromate (CTADC) in dichloromethane (DCM) in the presence of acetic acid and in the presence of a cationic surfactant. The rate of the reaction is highly sensitive to the change in [CTADC], [alcohol], [acid], [surfactant], polarity of the solvents, and reaction temperature. A Michaelis-Menten type kinetics was observed with respect to substrate. The chemical nature of the intermediate and the reaction mechanism were proposed on the basis of (i) observed rate constant dependencies on the reactants, that is, fractional order with respect to alcohol and acid and a negative order with respect to oxidant, (ii) high negative entropy change, (iii) inverse solvent kinetic isotope effect, k(H2O)/k(D2O) = 0.76, (iv) low primary kinetic isotope effect, kH/kD = 2.81, and (v) the k(obs) dependencies on solvent polarity parameters. The observed experimental data suggested the self-aggregation of CTADC giving rise to a reverse micellar system akin to an enzymatic environment, and the proposed mechanism involves the following: (i) formation of a complex between alcohol and the protonated dichromate in a rapid equilibrium, equilibrium constant K = 5.13 (+/-0.07) dm(3) mol(-1), and (ii) rate determining decomposition (k(2) = (7.6 +/- 0.7) x 10(-3) s(-1)) of the ester intermediate to the corresponding carbonyl compound. The effect of [surfactant] on the rate constant and the correlation of solvent parameters with the rate constants support the contribution of hydrophobic environment to the reaction mechanism.     

双(4-羧苯基)苯基氧化膦的定性定量分析

用差示扫描量热、元素分析、红外光谱、氢核磁共振等方法对自制双(4-羧苯基)苯基氧化膦(BCPPO)进行定性分析.其结构和纯度经确认后,紫外光谱扫描发现:BCPPO的吡啶溶液在302 nm波长处有稳定吸收,在6.0×10-5～3.6×10-3mol·L-1之间,吸光度与浓度呈线性关系.应用紫外-分光光度法对BCPPO进行定量分析时,相对标准偏差(n=5)在0.14%～0.25%之间,可有效避免反应副产物苯甲酸对测定的影响.     

Plasmonic Nanorattles as Next‐Generation Catalysts for Surface Plasmon Resonance‐Mediated Oxidations Promoted by Activated Oxygen

Nanorattles, comprised of a nanosphere inside a nanoshell, were employed as the next generation of plasmonic catalysts for oxidations promoted by activated O₂. After investigating how the presence of a nanosphere inside a nanoshell affected the electric‐field enhancements in the nanorattle relative to a nanoshell and a nanosphere, the SPR‐mediated oxidation of p‐aminothiophenol (PATP) functionalized at their surface was investigated to benchmark how these different electric‐field intensities affected the performances of Au@AgAu nanorattles, AgAu nanoshells and Au nanoparticles having similar sizes. The high performance of the nanorattles enabled the visible‐light driven synthesis of azobenzene from aniline under ambient conditions. As the nanorattles allow the formation of electromagnetic hot spots without relying on the uncontrolled aggregation of nanostructures, it enables their application as catalysts in liquid phase under mild conditions using visible light as the main energy input.     

在复合金属氧化物催化剂上丙烷直接氧化制丙烯酸

丙烷直接氧化制丙烯酸是近年来催化氧化的热点课题。MoVTe(Sb)NbO复合金属氧化物催化剂是该反应最重要的一类催化剂。本文对该类催化剂的制备化学包括活化方式以及决定催化性能的主要活性相结构等方面的新近认识进行了系统评述;依据丙烷催化转化的反应途径,总结了有关催化剂元素组分在反应中的作用与功能的最新进展,调变催化剂的粒子尺寸与形貌、晶相组成与结构、表面酸碱性与氧化还原性是获得优良催化性能的关键因素。