Ni(OH)2催化剂催化氧化醇的研究

采用共沉淀法制备了Ni(OH)2催化剂,该催化剂对温和条件下以分子氧为氧化剂的苯甲醇及烯丙醇类的氧化反应有十分理想的催化效果,并且完全可以通过简单的处理回收利用.     

固载化的TEMPO催化醇的氧化研究

醇被氧化为相应的醛或酮是有机合成中重要的官能团转化之一。有机小分子催化剂2,2,6,6-四甲基哌啶-1-氧自由基(TEMPO)催化醇的氧化反应是温和条件下选择性氧化醇的一个重要方法,在实验室和工业生产中得到了广泛应用。将TEMPO通过共价键嫁接在载体上,以实现催化剂的回收再用,一直是TEMPO催化研究的一个领域。文章综述了近年来固载化的TEMPO催化醇氧化反应的发展和最新研究进展。     

Iron(II, III)-Catalyzed Oxidation of Limonene by Dioxygen

Labile iron(II) and iron(III) complexes {[Fe^II(bpy)₂²⁺]_solv and [Fe^III(bpy)₂³⁺]_solv} in acetonitrile activate dioxygen for the oxidation of limonene to produce mainly carvone, carveol, limonene oxide, and perillaldehyde. Iron(III) complex is reduced by the substrate to iron(II) one, which activates dioxygen. Probably the catalyst interacts with substrate prior to the oxidation process. Perillaldehyde is likely formed directly from oxidation of methyl group (not via alcohol). However, the aldehyde is also reduced to perillyl alcohol by the reduced form of the catalyst.     

催化氧化醇类的反应研究进展

综述了用氧气或空气(分子氧)作为化学计量氧化剂,在催化剂作用下氧化醇类的研究进展。     

Iron(III)‐Catalyzed Halogenations by Substitution of Sulfonate Esters

A novel halogenation reaction from sulfonates catalyzed by iron(III) is described. The reaction can be performed as a stoichiometric or a catalytic version. This reaction provides a convenient strategy for the efficient access to structurally diverse secondary chlorides, bromides and iodides. The stereochemical course of the reaction is governed by the substrate and the experimental conditions. Secondary alcohols modified as quisylates or pysylates are substantially more reactive. Aliphatic quisylates proceed with overall inversion of configuration under catalytic conditions. Chemoselectivity in bismesylates was observed in favour of the secondary mesylate. Additionally, based on the experimental results, a possible catalytic cycle for the halogenation has been proposed.     

Palladium(II)‐Catalyzed Oxidation of Alcohols with Air as Reoxidant

Oxidation of primary and secondary aliphatic and secondary benzylic alcohols into their corresponding aldehydes and ketones was achieved in good yields with palladium catalysts using air as the reoxidant of palladium. The use of palladacycle 1 resulted in higher yields and a faster reaction than the use of Pd(OAc)₂ as the palladium source.     

An Efficient Catalytic Aerobic Oxidation of Alcohols in Water Using Hypervalent Iodine(V)

A transition metal‐free aerobic oxidation of alcohols to the corresponding aldehydes or ketones can be effectively catalysed by iodoxybenzene (PhIO₂)/Br₂/NaNO₂ in water.     

氮氧自由基催化醇选择性氧化反应的研究进展

醇选择性氧化成醛或酮的反应是有机合成中一个重要的研究领域,氮氧自由基(NO·)具有强氧化性,在加快产物醛或酮转化的同时,能有效地防止酸生成,是当前研究较多的醇催化氧化反应活性中心之一。主要介绍了含NO·结构催化剂体系催化醇选择氧化反应的研究进展,对含氮氧自由基结构化合物组成的均相及多相催化剂体系进行了归类总结,分析了催化醇氧化反应的方法及工艺条件方法的优缺点及反应机理,并展望了今后的研究发展方向。     

双水杨醛缩乙二胺合铜[Cu(Salen)]/O2催化氧化安息香

以72.8%的产率合成了双水杨醛缩乙二胺合铜配合物[Cu(Salen)],用正交试验法考察了该配合物对安息香的空气氧化反应的催化作用。实验发现,在水杨醛乙二胺合铜配合物的催化下,安息香经空气氧化生成苯偶酰的产率可达87.9%。     

The Radical Versus Non-radical Reactive Intermediates in the Iron(III) Porphyrin Catalyzed Oxidation Reactions by Hydroperoxides, Hydrogen Peroxide and Iodosylarene

In the catalytic reaction of an iron(III) porphyrin with t-BuOOH, CumOOH, H₂O₂ and C₆F₅IO, cyclohexene was used as a probe substrate. The selective hydroxylation of cyclohexene by hydroperoxides proceeds through radical path and this has been utilized for successful dioxygen activation/autooxidation. For other oxidants epoxide was the major product and the reactions proceed through non-radical path.     

Oxidation and Oxidative Bromination Reactions Catalyzed By a Reusable Polymer-Anchored Iron(III) Complex in Water at Room Temperature

A polymer-anchored iron(III) catalyst was synthesized and characterized. Its catalytic activity was evaluated for the oxidation of various alkenes, sulfides, aromatic alcohols and ethylbenzene with 30 % H₂O₂ as the oxidizing agent. The catalyst was also effective for the oxidative bromination reaction with 80–100 % selectivity of monobrominated products with H₂O₂/KBr at room temperature. The above reactions require a minimum amount of H₂O₂ and short reaction time. Most importantly, all the above reactions occur in aqueous medium. The catalyst can be facilely recovered and reused six-atimes without significant decrease in its activity and selectivity.     

Oxidation of polycyclic aromatic hydrocarbons with hydrogen peroxide catalyzed by Iron(III)porphyrins

A variety of iron-metallated functional porphyrins have been synthesized and their catalytic activity to oxidize polycyclic aromatic hydrocarbons, (PAHs) using hydrogen peroxide as oxidant was investigated. It was found that iron-metallated porphyrins bearing strong electronegative groups at β-pyrrolic positions show an exceptionally high catalytic efficiency.     

Efficient Esterification of Fatty Acids with Alcohols Catalyzed by Zr(SO4)2 · 4H2O Under Solvent-Free Condition

Zirconium sulfate (Zr(SO₄)₂ · 4H₂O) was an efficient catalyst for the esterification of fatty acids and alcohols under solvent-free condition. The esterification of fatty acid with branched alcohols using Zr(SO₄)₂ · 4H₂O catalyst gave a good yield of the corresponding ester. The zirconium sulfate Bronsted acid site was suggested to be the catalytically active species in this reaction. In addition, Zr(SO₄)₂ · 4H₂O compound is a potential green catalyst due to its high catalytic activity and low toxicity. This compound is also cost effective, easy to handle, is easily recovered by simple filtration and can be recycled for further reactions.     

Polymerization of Aniline Using Iron(III) Catalyst and Ozone,and Kinetics of Oxidation Reactions in the Catalytic System

The environmentally benign polymerization of aniline provided polyaniline with an emeraldine structure by using iron(III) and ozone which is easily converted from oxygen in air. The influence of the reaction temperature upon the molecular weight of the polyaniline in this system is different from that in the polymerization of aniline using ammonium peroxodisulfate as an oxidant. Although the polyaniline prepared here has low molecular weight, the low molecular weight of the polyaniline does not significantly influence the electrical conductivity of cast films. In contrast, this can provide an advantage for the engineering of polyaniline through solution‐processing. Kinetics of oxidation reactions in the polymerization, systematically investigated here, has revealed that polyaniline is produced catalytically in terms of iron(III) and that an oxidation reaction of iron(II) to iron(III) could be a rate‐determining step in the polymerization.     

Iron‐Catalyzed Oppenauer‐Type Oxidation of Alcohols

A (hydroxycyclopentadienyl)iron dicarbonyl hydride catalyzes the Oppenauer‐type oxidation of alcohols with acetone as the hydrogen acceptor. Many functional groups are tolerant to the oxidation conditions. The same complex also catalyzes the dehydrogenation of diols to lactones. A mechanism involving the formation of iron‐alcohol complexes and their rapid ligand exchange with free alcohols is proposed. The trimethylsilyl groups on the cyclopentadienyl ligand of the catalyst play a critical role in stabilizing the iron hydride and increasing the catalyst lifetime.     

Selective Iron‐Catalyzed Oxidation of Benzylic and Allylic Alcohols

A convenient and selective oxidation of alcohols with hydrogen peroxide to give aldehydes and ketones has been developed. Using in situ generated iron chloride complexes [Fe( L3 )₂Cl_n] [n=0–1, L3 =6‐(N‐phenylbenzimidazoyl)‐2‐pyridinecarboxylic acid], aldehydes and ketones were obtained in good yield and excellent selectivity after a short reaction time at room temperature.     

Aerobic Oxidation of Alcohols Catalyzed by Copper Nanoparticle-Polyacrylamide/SBA-15 as Novel Polymer-Inorganic Hybrid

Heterogeneous hybrid polymer-inorganic copper nanoparticle-polyacrylamide/SBA-15 was prepared, characterized and tested as a catalyst for efficiently selective oxidation of alcohols to aldehydes in high yields under molecular oxygen in n-hexane solvent. The catalyst can be recycled over six-times without significant loss of activity.