用H2O2氧化苯乙烯合成苯甲酸

摘要：以30％H2O2做为氧化剂,钨酸钠与含O双齿有机配体(草酸)形成的络合物为催化剂,在无有机溶剂、无相转移剂的条件下,研究了苯乙烯氧化制苯甲酸的反应。研究结果表明,最佳反应条件为：苯乙烯100．0mmol,n(钨酸钠)：n(草酸)：n(苯乙烯)：n(30％H2O2)=2．0：3．2：100．0：440．0,于92℃反应24h,苯甲酸收率98．6％。用GC—MS跟踪了氧化过程中4种主要物质苯乙烯、1-苯基邻二醇、羟基苯乙酮及苯甲酸含量随反应时间的变化关系,提出了其主要氧化机理为苯乙烯经过环氧化反应、水解生成生成1-苯基邻二醇,1-苯基邻二醇再氧化为羟基苯乙酮、最后氧化为苯甲酸。     

An H2O2 Molecule Stabilized inside Open-Cage C60 Derivatives by a Hydroxy Stopper

An H₂O₂ molecule was isolated inside hydroxylated open-cage fullerene derivatives by mixing an H₂O₂ solution with a precursor molecule followed by reduction of one of carbonyl groups on its orifice. Depending on the reduction site, two structural isomers for H₂O₂@open-fullerenes were obtained. A high encapsulation ratio of 81 % was attained at low temperature. The structures of the peroxosolvate complexes thus obtained were studied by ¹H NMR spectroscopy, X-ray analysis, and DFT calculations, showing strong hydrogen bonding between the encapsulated H₂O₂ and the hydroxy group located at the center of the orifice. This OH group was found to act as a kinetic stopper, and the formation of the hydrogen bonding caused thermodynamic stabilization of the H₂O₂ molecule, both of which prevent its escape from the cage. One of the peroxosolvates was isolated by HPLC, affording H₂O₂@open-fullerene with 100 % encapsulation ratio, likely due to the intramolecular hydrogen-bonding interaction.     

钌/酸共催化邻氨基苯甲醇和芳基端炔合成喹啉衍生物

以邻氨基苯甲醇为原料进行催化脱氢反应,经过对催化体系的一系列筛选,最终采用[RuCl₂(p-cymene)]₂/AgOTf共催化体系,使邻氨基苯甲醇发生催化脱氢和芳基端炔发生交叉偶联反应,并以39%~47%的收率获得合成一系列2-芳基喹啉衍类生物,发展了邻氨基苯甲醇与芳基末端炔烃合成喹啉衍类生物的新方法,是对喹啉类衍生物合成方法的一个重要补充。     

Competition Between O2 and H2O2 in the Oxidation of Fe(II) in Natural Waters

The oxidation rates of nanomolar levels of Fe(II) in seawater (salinity S = 36.2) by mixtures of O₂ and H₂O₂ has been measured as a function of pH (5.8–8.4) and temperature (3–35∘C). A competition exists for the oxidation of Fe(II) in the presence of both O₂ (μ mol⋅L⁻¹ levels) and H₂O₂ (nmol⋅L⁻¹ levels). A kinetic model has been applied to explain the experimental results that considers the interactions of Fe(II) with the major ions in seawater. In the presence of both oxidants, the hydrolyzed Fe(II) species dominate the Fe(II) oxidation process between pH 6 and 8.5. Over pH range 6.2–7.9, the FeOH⁺ species are the most active, whereas above pH 7.9, the Fe(OH)⁰₂ species are the most active at the levels of CO²⁻₃ concentration present in seawater. The predicted Fe(II) oxidation rate at [Fe(II)]₀ = 30nmol⋅L⁻¹ and pH = 8.17 in the oxygen-saturated seawater with [H₂O₂]₀ = 50nmol⋅L⁻¹ (log ₁₀ k = −2.24s⁻¹) is in excellent agreement with the experimental value of log ₁₀ k = −2.29s⁻¹ ([H₂O₂]₀ = 55nmol⋅L⁻¹, pH = 8).     

Epoxidation of 1,4-Diaroyl Ethene Derivatives in the Presence of UHP or H2O2

Hydrogen peroxide (H₂O₂) or urea–hydrogen peroxide (UHP) in basic media react with carbon–carbon double bonds of 1,4-diaroyl ethenes to produce the corresponding epoxides.     

Synthesis of Six-Membered Functionalized Carbocyclic Compounds by One-Pot Reaction of Hydroquinone Derivatives and Dienes

A general method for one-pot reaction of hydroquinone derivatives and dienes has been developed. The system of Pb₃O₄ in tetrahydrofuran–trifluoroacetic acid was found to play dual roles as oxidant for the generation of quinones in situ and as catalyst for the Diels–Alder cycloaddition, which makes the one-pot reaction efficient and easy to carry out. Using this method, a variety of six-membered functionalized carbocyclic compounds can be easily prepared in medium to excellent yields at room temperature.      

碱催化醛、丙二腈和邻苯二甲酰肼的、三组分反应合成酞嗪衍生物

经过实验验证引入水有利于芳香醛、丙二腈和邻苯二甲酰肼三组分的反应进行,催化量的有机碱三乙胺(Et 3 N)或无机碱磷酸氢二钾(K 2 HPO 4[DK1]·3H 2 O)可以在常规条件下促进该反应。本文以39%~97%的产率合成一系列1 H-吡唑[1,2-b]酞嗪-5,10-二酮衍生物。两种催化剂均溶于水,因此,反应结束后催化剂的分离与产物提纯简便易行。此方法具有反应条件温和、绿色环保、操作简单、后处理方便等特点。     

Electrochemical Formation of Fe(IV)=O Derived from H2O2 on a Hematite Electrode as an Active Catalytic Site for Selective Hydrocarbon Oxidation Reactions

The high-valence iron species (Fe(IV)=O) in the cytochrome P450 enzyme superfamily is generated via the activation of O₂, and serves as the active center of selective hydrocarbon oxidation reactions. Furthermore, P450 can employ an alternate route to produce Fe(IV)=O, even from H₂O₂ without O₂ activation. Meanwhile, Fe(IV)=O has recently been revealed to be the reactive intermediate during H₂O oxidation to O₂ on hematite electrodes. Herein, we demonstrated the generation of Fe(IV)=O on hematite electrodes during the electrochemical oxidative decomposition of H₂O₂ using in situ UV-visible absorption spectra. The generation of Fe(IV)=O on hematite electrodes from H₂O₂ exhibited 100 mV lower overpotential than that from H₂O. This is because H₂O₂ serves not only as the oxygen source of Fe(IV)=O, but also as the additional oxidant. Finally, we confirmed that the Fe(IV)=O generated on hematite electrodes can serve as the catalytic site for styrene epoxidation reactions.     

Oxidation with the H2O2—VO3 −—pyrazine-2-carboxylic acid reagent

Aromatic hydrocarbons are oxidized with hydrogen peroxide in the presence of catalytic amounts of VO₃ ^– and pyrazine-2-carboxylic acid into phenols (provided excess hydrocarbon is used) or into quinones (at high H₂O₂ concentrations). 2-Propanol, ethanol, cyclohexanol, and benzyl alcohol are transformed into the corresponding aldehydes and ketones under the same conditions (without a solvent or in MeCN).For part 1, see ref. 1.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1394–1396, August, 1993.     

Catalytic oxidation of furan and hydrofuran compounds 8. Synthesis of 5-ethoxycarbonyl-4-hydroxy-3-oxo-2(3H)-furanone by the oxidation of furfural in the system aqueous H2O2-VOSO4-ethanol

The special features of the oxidation of furfural by aqueous hydrogen peroxide in the presence of vanadyl sulfate and ethanol has been studied for the first time. It has been established that this reaction proceeds with the formation of previously unknown oxidation products of furan compounds, one of which was isolated from the reaction mixture as the ethyl ester. It was established by spectral methods and qualitative reactions that this product is 5-ethoxycarbonyl-4-hydroxy-3-oxo-2(3H)-furanone. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 386–392, March, 2008.     

Oxidation by a H2O2-vanadium complex-2-pyrazinecarboxylic acid reagent

Evidence for the formation of hydroxyl radicals and their participation in hydrocarbon oxidation by a H₂O₂-vanadium complex-2-pyrazinecarboxylic acid reagent has been obtained by the spin trap method and kinetically, by competitive oxidation of a benzenealiphatic alcohol mixture.For part 2, see Ref. l.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1212–1214, July, 1994.This work was financially supported by the Russian Foundation for Basic Research (project No. 93-03-5226) and the International Science Foundation (Grant No. MMS000). The authors are grateful to D. Attanasio and L. Suber (Italy) for help in the work and to S. N. Dobryakov and Yu. N. Kozlov for their participation in the discussions.     

Reaction of Anthranilonitrile with Some Active Methylene Reagents: Synthesis of Some New Quinoline and Quinazoline Derivatives

Anthranilonitrile (1) reacts with ethyl cyanoacetate and its dimer, malononitrile, cyanothioacetamide and N‐arylidene cyanoacetohydrazides 12a–c to afford pyrano[2,3‐b]quinoline 5, cyanomethyl‐quinazoline 10, pyrazolo[2,3‐a]quinazoline 12 and triazolo[4,3‐a]‐quinoline derivatives 16a–c, respectively. Structures and conceivable mechanisms are discussed.     

变量选择中的正交变换法及苯酚和苯胺类衍生物色谱比移值的预测

正交变换法是变量选择的一种可行方法,但该种方法非常依赖于正交变换过程中变量的排序,侧重比较了不同排序方法,其中,后退法可以得到较好的结果。文中采用此种方法对由苯酚及苯胺类化合物所衍生的变量进行了正交变换,并对上述化合物的色谱比移值进行了预测。同时,与前进选择法、后退剔除法和逐步回归法几种传统方法进行了比较,得到了有启示性的结果。     

Synthesis of Benzimidazoles via Iron-Catalyzed Aerobic Oxidation Reaction of Imine Derivatives with o-Phenylenediamine

A simple and efficient protocol for preparing benzimidazoles via Fe(NO₃)₃ · 9H₂O-catalyzed aerobic oxidation reaction of imine derivatives with o-phenylenediamine. This process uses air as an economical and green oxidant, tolerates a wide range of substrates, and affords the targeted benzimidazoles in moderate to excellent yields.     

gamma-1,2-H2SiV2W10O40] immobilized on surface-modified SiO2 as a heterogeneous catalyst for liquid-phase oxidation with H2O2

An organic-inorganic hybrid support has been synthesized by covalently anchoring an N-octyldihydroimidazolium cation fragment onto SiO2 (denoted as 1-SiO2). This modified support was characterized by solid-state 13C, 29Si, and 31P NMR spectroscopy, IR spectroscopy, and elemental analysis. The results showed that the structure of the dihydroimidazolium skeleton is preserved on the surface of SiO2. The modified support can act as a good anion exchanger, which allows the catalytically active polyoxometalate anion [gamma-1,2-H2SiV2W10O40]4- (I) to be immobilized onto the support by a stoichiometric anion exchange (denoted as I/1-SiO2). The structure of anion I is preserved after the anion exchange, as confirmed by IR and 51V NMR spectroscopy. The catalytic performance for the oxidation of olefins and sulfides, with hydrogen peroxide (only one equivalent with respect to substrate) as the sole oxidant, was investigated with I/1-SiO2. This supported catalyst shows a high stereospecificity, diastereoselectivity, regioselectivity, and a high efficiency of hydrogen peroxide utilization for the oxidation of various olefins and sulfides without any loss of the intrinsic catalytic nature of the corresponding homogeneous analogue of I (i.e., the tetra-n-butylammonium salt of I, TBA-I), although the rates decreased to about half that with TBA-I. The oxidation can be stopped immediately by removal of the solid catalyst, and vanadium and tungsten species can hardly be found in the filtrate after removal of the catalyst. These results rule out any contribution to the observed catalysis from vanadium and tungsten species that leach into the reaction solution, which means that the observed catalysis is truly heterogeneous in nature. In addition, the catalyst is reusable for both epoxidation and sulfoxidation without any loss of catalytic performance.