铁改性的HMS分子筛催化苯酚羟基化反应合成二酚

邻苯二酚和对苯二酚是重要的精细化工中间体,在各个行业中具有广泛的应用。苯酚与过氧化氢反应合成苯二酚是一条反应条件温和、环境友好的合成路线,该合成路线的关键是催化剂的选择和反应条件的优化。本文以铁改性的HMS分子筛为催化剂,研究了金属负载量、催化剂使用量、反应温度、反应时间等因素对催化性能的影响,优化了反应条件。以水为溶剂,n(Fe)∶n(Si)=0.04,n(苯酚)∶n(H2O2)=2∶1,反应温度50℃,催化剂用量0.1g,反应4h,苯酚的转化率达45.5%,苯二酚选择性为94.9%。N2吸附-脱附结果表明,Fe/HMS具有良好的介孔结构,铁进入HMS材料的骨架中,并且催化剂具有良好的稳定性,循环使用后骨架保持完整。     

Regioselectivity of olefin oxidation by iodosobenzene catalyzed by metalloporphyrins : control by the catalyst

The regioselectivity of the oxidation of three monosubstituted olefins, 6-phenoxyhex-1-ene, hex-1-ene and styrene, by iodosobenzene in the presence of various Fe-, Mn- or Cr-tetraaryl-porphyrins, was studied. It was found that, besides epoxides, known products from such systems, allylic alcohols and aldehydes were formed, the latter not being derived from the corresponding epoxides. The relative importance of these reactions greatly depends upon both the metal and porphyrin constituents of the catalyst. More particularly, the competition between epoxidation and allylic hydroxylation can be efficiently controlled by non-bonded interactions between the olefin and porphyrin substituents. No hydroxylation of the aromatic rings and no oxidative dealkylation of the ether function was detected.     

Effect of substituents in the ligand on oxidation of alkanes catalyzed by binuclear oxo-bridged iron complexes

Oxidation of alkanes (methane, ethane, hexane, and cyclohexane) by hydrogen peroxide andtert-butyl hydroperoxide in acetonitrile catalyzed by binuclear -oxo-bridged iron complexes [Fe₂OL₄(H₂O)₂](ClO₄)₄ and [Fe₂OL₂PhCOO)₂(H₂O)₂](ClO₄)₂, where L = bpy, 4,4-Me₂bpy, 4,4-(ClCH₂)₂bpy, phen, and 5-NO₂phen, was studied. It was shown that the nature of the substituent in the ligand affects both the rate of the catalyzed peroxide decomposition and catalytic activity of the complexes studied in the alkane oxidation.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2518–2520, December, 1995.This work was financially supported by the Russian Foundation for Basic Research (Project No. 94-03-08529), the International Science Foundation (Grant No. REUOOO), the European Foundation INTAS (Grant No. 93-315), and Amoco Company (USA).     

Photooxidation of alkanes by oxygen catalyzed by CuCl2 in acetonitrile

The irradiation of a solution of anhydrous CuCl₂, taken as a photocatalyst, and an alkane in acetonitrile in the air with visible light (>320 nm) leads to the formation of alcohol and ketone products.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 698–699, March, 1990.     

Ring-opening with one dioxygen molecule in the coupled oxidation of iron tetraarylporphyrins

A dioxygen molecule was activated on the iron complex of tetraarylporphyrins and both oxygen atoms of the O₂ molecule were added to cleave the macrocycle to yield a linear tetrapyrrole intermediate, from which two linear tetrapyrrole products, biladienone and bilindione, are formed, as revealed by isotope labeling experiments with oxygen-18.     

Ferric chloride catalyzed photooxidation of alkanes by air in organic solvents

In the presence of catalytic amounts of FeCl₃, alkanes (cyclohexane, n-hexane), toluene and ethylbenzene are oxidized by air oxygen to CH₃CN, (CH₃)₂CO or CH₂Cl₂ under visible light irradiation to yield ketones and alcohols.

---

FeCl₃ (, -), CH₃CN, (CH₃)₂CO CH₂Cl₂ .

     

Chemoselective C-H oxidation of alcohols to carbonyl compounds with iodosobenzene catalyzed by (salen)chromium complex

Primary and secondary alcohols with benzylically and allylically activated C-H bonds are chemoselectively oxidized to the corresponding carbonyl compounds by the (salen)Cr(III) complex I as the catalyst and iodosobenzene as the oxygen source; the oxidizing species is the Cr(V) oxo complex. Allylic alcohols with fully substituted double bonds give appreciable amounts of epoxides besides the C-H oxidation products enones, while saturated alcohols are less readily oxidized.     

Ligand topology variations and the importance of ligand field strength in non-heme iron catalyzed oxidations of alkanes

A series of iron(II)-bis(triflate) complexes [Fe(L)(OTf)2] containing linear tetradentate bis(quinolyl)-diamine and bis(quinolylmethyl)-diamine ligands with a range of ligand backbones has been prepared. The coordination geometries of these complexes have been investigated in the solid state by X-ray crystallography and in solution by 1H and 19F NMR spectroscopy. Because of the labile nature of high-spin iron(II) complexes in solution, dynamic equilibria of complexes with different coordination geometries (cis-alpha, cis-beta, and trans) are observed with certain ligand systems. In these cases, the geometry observed in the solid-state does not necessarily represent the only or even the major geometry present in solution. The ligand field strength in the various complexes has been investigated by variable-temperature (VT) magnetic moment measurements and by UV-vis spectroscopy. The strongest ligand field is observed with the most rigid ligand that generates [Fe(L)(OTf)2] complexes with a cis-alpha coordination geometry, and the corresponding [Fe(L)(CH3CN)2]2+ complex displays spin crossover behavior. The catalytic properties of the complexes for the oxidation of cyclohexane have been investigated using hydrogen peroxide as the oxidant. An increased flexibility in the ligand results in a weaker ligand field, which increases the lability of the complexes. The activity and selectivity of the catalysts appear to be related to the strength of the ligand field and the stability of the catalyst.     

Mono-Substitution of iron pentacarbonyl catalyzed by polynuclear iron carbonyl anions

The specific formation of LFe(CO)₄ (L = PPh₃, P(OPh)₃, P(OMe)₃ can be achieved by the reaction of Fe(CO)₅ with L in the presence of a catalytic amount of iron carbonyl anion. A convenient synthetic procedure was developed in which the iron carbonyl anion catalyst is generated in situ. It is shown that the mechanism does not proceed by the simple cleavage of the Fe₂(CO)₈^2? or Fe₃(CO)₁₁^2? anions, because triphenylphosphine reacts with these anions in the absence of Fe(CO)₅ to produce (PPh₃)₂Fe(CO)₃.     

Hydroperoxidation of alkanes with hydrogen peroxide catalyzed by aluminium nitrate in acetonitrile

The first example of alkane oxygenation with hydrogen peroxide catalyzed by a non-transition metal derivative (aluminium) is reported. Heating (70 °C) a solution of an alkane, RH, hydrogen peroxide (70% aqueous) and a catalytic amount of Al(NO₃)₃·9H₂O in air for a few hours afforded the corresponding alkyl hydroperoxide, ROOH. With cyclooctane, the hydroperoxide yield attained 31% and the maximum turnover number was 150. It is proposed on the basis of measurements of the selectivity parameters for the oxidation of linear and branched alkanes and a kinetic study that the oxidation occurs with the participation of hydroxyl radicals.     

Hydroxylation of fullerenes modified with iron nanoparticles

The possibility was explored for synthesizing polyhydroxylated fullerenes directly from soot containing iron nanoparticles stabilized by carbon shell.     

Adsorption of colloidal trivalent iron on alumina

The adsorption of colloidal trivalent iron on neutral, acid and basic Al₂O₃ from aqueous solution as a function of pH has been studied. The dependence of sorption of pH is characterized by a maximum, whose position depends on the nature of colloidal particles and surface properties of the sorbents. Adsorption isotherms for the given range of sorbent loading can be expressed by the Langmuir adsorption equation.     

Intermediates of homogeneous deuterium exchange in alkanes catalyzed by Pt(II)

The rate constants and distribution of deuterated products of the H-D exchange in alkanes (C₁–C₈) have been measured for aqueous solutions of K₂PtCl₄. The reaction involves the intermediate formation of alkyl, 1,1-(carbene). 1,2-(olefin), 1,3-(cyclopropane) and 1,4-(cyclobutane) type hydrocarbon complexes. The selective attack of Pt(II) on the primary, secondary and tertiary C–H bonds in alkanes (110) is due to the predominance of steric over polar effects.

---

H-D (C₁–C₈) K₂PtCl₄ , , 1,1-(), 1,2-(), 1,3-() 1,4-() . Pt(II) ., ., . C–H (110) .

     

三氯化铁催化合成三芳基甲烷化合物的研究

三甲基芳烷类化合物在染料、生物、医药领域具有的重要应用价值。本文研究了2,4,6-三甲基苯甲醛和N,N-二甲基间溴苯胺通过缩合反应制备三芳基甲烷化合物,考察了催化剂种类、反应溶剂、反应温度和反应时间对产物收率的影响。确定合成条件为以无水Fe Cl3作为催化剂、对二甲苯为溶剂、反应温度为128℃,反应时间为32h,目标产物收率达到80%左右,产物结构经质谱和氢核磁共振谱表征确认。     

两亲聚离子液体-钒掺杂杂多酸离子复合体催化的苯氧化羟化

以N,N-二甲基烯丙基胺、1-氯乙酸、Well-Dawson构型H7[P2Mo17VO62]、,H8[P2Mo16 V2O62],、H9[P2Mo15 V3 O62]为起始原料,经季铵化、自由基聚合、分子自组装构建了三种两亲聚离子液体-钒掺杂杂多酸离子复合体PPIL-1 ～3,离子复合体集两亲活性、氧化催化活性和多孔性与一体,以其为非均相催化剂,工业级30％过氧化氢为氧化剂,在温和反应条件下,实现了苯一步氧化羟化制备苯酚.当离子复合体用量为0.1g,苯10mmol,过氧化氢20mmol,以15mL乙腈为溶剂,反应温度60℃,反应时间4h,苯酚产率37.3％.离子复合体经离心分离、溶剂洗涤、真空干燥即可再生循环使用,循环使用6次,催化活性基本保持不变.     

Synthesis of meso-extended tetraarylporphyrins

The synthesis of five new meso-tetraarylporphyrins having pyridine, pyrimidine, or nitrile groups extending tetragonally via alkynyl linkages from the para positions is described. The radial extension is nearly double that of common porphyrins such as tetra-p-pyridylporphyrin. Practical quantities can be produced by Pd-coupling protocols when traditional methods fail. Applications of these extended porphyrins in the area of porous metal-organic frameworks are anticipated.