2,2,6,6-四甲基哌啶氧化物催化的高选择性羟基氧化反应

次氯酸钠在2,2,6,6-四甲基哌啶氧化物(TEMPO)的催化下,可在温和的条件下选择性氧化胆酸类化合物的C3位羟基.该方法提供了与常规的氧化剂相反的区域选择性,为胆酸类化合物的结构改造提供了简洁的路线.     

溴酸钠和氯化铁为助催化剂2,2,6,6-四甲基-N-氧化哌啶催化醇的氧化

建立了溴酸钠和氯化铁为助催化剂2,2,6,6-四甲基-N-氧化哌啶(NaBrO₃-FeCl₃-TEMPO)新型催化体系,以苯甲醇的氧化为研究对象,得出各成分与底物的最佳物质的量比为:2%TEMPO、35%NaBrO₃、3.7%H₂SO₄、2%FeCl₃·6H₂O。该体系在室温下可有效实现芳香醇、脂肪醇及杂环醇的氧化,收率高(99%)、选择性强(99%),在无氧条件下,仍表现出较好的催化活性。     

N,N''''-二(2,2,6,6-四甲基-4-哌啶基)-1,6-己二胺合成研究

采用超声波辐射使2,2,6,6-四甲基-4-哌啶酮(俗称三丙酮胺)和己二胺在室温条件下发生亲核加成反应,加成产物经减压蒸馏脱除水分子生成西佛碱,收率达75%;然后,在55～80℃、1.9～2.0 MPa条件下,以W-7型或-4型骨架镍作催化剂,对该西佛碱氢化,得到N,N'-二(2,2,6,6-四甲基-4-哌啶基)-1,6己二胺.     

2,2,6,6-四甲基哌啶氧自由基/Ca(ClO)2催化氧化甲基葡糖苷制备葡醛酸

采用2,2,6,6-四甲基哌啶氧自由基/Ca(ClO)2体系选择氧化甲基葡萄糖苷(简称甲苷)合成了葡萄糖甲苷酸盐,再用硫酸酸解葡萄糖甲苷酸盐,得到葡萄糖醛酸和副产物硫酸钙。考察了氧化工艺条件对葡萄糖醛酸收率的影响;用pH计监控反应过程,反应中间体和终产物用UV和HPLC检测。结果表明,该体系对甲苷伯羟基的氧化具有较好的催化活性和反应选择性,葡萄糖醛酸收率达到92%,且金属离子易于去除。和传统的淀粉HNO3氧化法工艺相比,该方法具有资源节约、环境友好的特点。     

用离子抑制色谱法分析二(2,2,6,6-四甲基-4-哌啶基)马来酸酯合成反应液

建立了用离子抑制色谱法分析二（２,２,６,６－四甲基－４－哌啶基）马来酸酯合成反应液的方法。平均回收率为９８．８％,相对标准偏差为０．５６％,测量的平均相对偏差不大于５．０％。方法简单、快速,可用于工艺条件的选择和质量检测。     

电化学促进2,2,6,6-四甲基哌啶氧化物(TEMPO)介导的甘氨酸衍生物氧化脱氢Povarov/串联反应（英文）

研究了电化学氧化甘氨酸衍生物与烯烃之间的氧化脱氢Povarov/串联反应,其中氮氧自由基2,2,6,6-四甲基哌啶氧化物(TEMPO)作为媒介降低了电化学反应的电位,避免了某些富电子的芳胺在较高电位下的过氧化.它为甘氨酸衍生物的氮-α位官能团化提供了潜在的途径,并通过Shono氧化与Povarov反应的结合,开发了一种在温和条件下高产率合成喹啉衍生物的有效方法.     

2,2,6,6-四甲基-3,5-庚二酮的制备

在NaH存在下,3,3-二甲基丁酮和3,3-二甲基丁酸甲酯缩合制备了2,2,6,6-四甲基-3,5-庚二酮(1000g),收率66％,纯度可以达到98％(GC分析)。     

温度对4-甲基丙烯酸2,2,6,6-四甲基哌啶醇酯与苯乙烯自由基共聚活性的影响

本文研究了4-甲基丙烯酸2,2,6,6-四甲基哌啶醇酯和苯乙烯在不同温度下的自由基共聚合反应。发现在石油醚、苯和二甲基甲酰胺等溶剂中,反应温度对共聚活性的影响不同。用NMR法测定了单体与溶剂的络合常数;计算了单体与溶剂相互作用的活化能和活化熵,依此对共聚活性与温度之间的关系进行了讨论。     

2,2,6,6-四甲基哌啶-1-氧自由基促进的钒基催化剂催化苯直接氧化制苯酚

以钒基化合物为催化剂,在TEMPO(2,2,6,6-四甲基哌啶-1-氧自由基)存在下,能形成快速催化分子氧氧化苯制苯酚的催化体系.在反应过程中,由类似芬顿试剂反应过程生成的羟基自由基亲核进攻苯环,形成羟基环己二烯自由基;该羟基氢可在TEMPO存在的催化体系中消除,同时苯环氢可立即转移至氧原子而生成苯酚.在以[(CH3)...     

基于四氮配体的铜配合物/TEMPO催化的苄醇与烯丙基醇的氧化反应

发展了非血红素类四氮配体的铜配合物和2,2,6,6-四甲基哌啶-氮-氧自由基(TEMPO)相结合的催化体系,应用于分子氧参与的伯醇氧化反应.该体系具有条件温和、高效、高选择性、无需任何助剂和底物(包括苄醇、烯丙基醇和含杂原子伯醇)使用性强等优点.此外,利用高分辨质谱和紫外-光谱等对反应活性中间体进行了初步探讨.     

三氮唑配合物[Cu2(CH3COO)4(C4H8N4)2]·2CH3CN的合成及晶体结构

Cu(CH₃COO)₂和4-氨基-3,5-二甲基-1,2,4-三氮唑反应制得标题化合物的单晶[Cu₂(CH₃COO)₄(C₄H₈N₄)₂]·2CH₃CN。晶体属三斜晶系,空间群,a=8.266(2),b=8.585(2),c=10.741(2)Å,α=75.58(3),β=88.     

磷改性Cr2O3/Al2O3催化4-乙基酚转化制轻质芳烃

以烷基酚转化为轻质芳烃（苯和甲苯）为目标，制备了Cr₂O₃/Al₂O₃催化剂，并以4-乙基酚为模型化合物研究了其加氢反应性能。体积空速、氢油比、反应压力和温度升高时，脱烷基率、芳烃总选择性、轻质芳烃选择性呈先增大后减小的趋势，反应温度对转化率影响较大。以不同浓度磷酸对Cr₂O₃/Al₂O₃进行改性，随着磷酸用量的增大，催化剂酸量总体增大，主要是弱酸和中强酸，酸强度先增加后降低，磷酸用量较高时，弱酸增加幅度较大。与未改性相比，质量分数8%磷酸改性Cr₂O₃/Al₂O₃上4-乙基酚转化率99.5%，脱烷基率提升9.4%，达74.4%，轻质芳烃选择性提高4.0%，达到57.0%，以较高选择性实现了转化制轻质芳烃，同时，芳烃总选择性高达80.4%，较高程度保持了芳环不被破坏。提出了Cr₂O₃/Al₂O₃上4-乙基酚加氢反应的路径并对反应机理进行了研究。     

[Cu(TO)2(H2O)4](PA)2的合成和晶体结构

[Cu(TO)₂(H₂O)₄](PA)₂ was prepared by mixing the aqueous solution of 1,2,4-triazol-5-one(TO) and Cu(PA)₂. The molecular structure and crystal structure of the title complex was determined by X-ray single crystal diffraction method. The crystal is triclinic, space group with a=0.7321(1)nm,b=0.7474(2)nm,c=1.3649(3)nm;α=88.65(2)°,β=85.63(1)°,γ=63.35(1)°;V=0.6655(2)nm³,Z=1. The Cu²⁺ coordinated with two TO molecule through its 2-nitrogen atom and four water molecules and showed an octahedral configuration.     

The effect of the nature of the substituent at the nitrogen atom on transformations of 3-bromo-2,2,6,6-tetramethyl-4-piperidinone and its 1-hydroxy and 1-oxyl derivatives under conditions of the Favorsky rearrangement

3-Bromo-2,2,6,6-tetramethyl-4-oxopiperidine-1-oxyl reacts with NH₄OH to give 3-carbamoyl-2,2,5,5-tetramethylpyrrolidine-1-oxyl, a product of the Favorsky rearrangement. 3-Bromo-2,2,6,6-tetramethyl-4-piperidinone is transformed under these conditions into a bicyclic amino ketone, while its 1-hydroxy derivative affords acyclic nitrosoenone. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1189–1191, June, 1997.     

Formation of C4 Oligomers in Hydrogenation of Acetylene over Pd/Al2O3 and Pd/TiO2 Catalysts

Selectivity of product formation has been tested in hydrogenation of acetylene over 0.3 wt.% Pd/-alumina and 0.5 wt.% Pd/TiO₂catalysts. Non-steady-state regime of catalyst operation was tested in pulse-flow experiments. Significant carbon poisoning appears to be a necessaryrequisite for selective formation of ethylene. The effect of hydrogen and acetylene partial pressure has been tested on the selectivity of C₄products. At 273–298 K the catalysts showed 26–35% selectivity for C₄ hydrocarbons and <2.5% for ethane production at conversionsof 30–40%. Deuterium distribution in ethylene and 1,3-butadiene and the deuterium content of the surface hydrogen pool have been compared and mechanismof diene formation has been discussed.     

Synthesis and Characterization of Organically Templated Copper Halides with Zero and One-dimensional Hybrid Structures: (nbq)4Cu4I8 and [(ipq)2(Cu5I7)] n

Two new organically templated copper halides, (nbq)₄Cu₄I₈ (1) and [(ipq)₂(Cu₅I₇)] _n (2) have been synthesized in the presence of nbq⁺ and ibq⁺ (nbq⁺ = N-(n-butyl)-quinolinium, ibq⁺ = N-(iso-pentyl)-quinolinium) acting as structure-directing agents(SDAs). Both of the compounds present hybrid structures with SDAs and inorganic moieties being incorporated. In 1, tetrameric Cu₄I₈ ⁴⁻ anion is composed by edge-sharing CuI₄ tetrahedrons and CuI₃ planar triangles. But the inorganic framework of 2 presents one-dimensional arrangement which results from the tetrahedron CuI₄ and pseudo trigonal pyramid CuI₃ through edge-sharing fashion. Electrostatic interactions between organic counter cations and inorganic moieties could be observed and contribute to the crystal packing. Both compounds are further characterized by IR, UV–Vis, elemental analysis, fluorescence and cyclic voltammetry.     

Selective oxidation of octadecan-1-ol to octadecanoic acid over Co3O4/SiO2 catalysts

Factors (reaction temperature, reaction time, flow rate of oxygen, amount of catalyst, etc.) influencing the catalytic properties of Co₃O₄/SiO₂catalyst in the oxidation octadecan-1-ol to octadecanoic acid were investigated. The catalysts were characterized by means of XRD, FT-IR and N₂-adsorption. The experimental results indicate that under the optimal condition the selectivity to octadecanoic acid reached 97.5 % over 5 % Co₃O₄/SiO₂ catalyst.This revised version was published online in December 2005 with corrections to the Cover Date.     

A new route to the synthesis of thieno[2,3-d]pyrimidin-4（3H）-one derivatives catalyzed by 12-tungstophosphoric acid （H3PW12040）

Heteropoly acid H3PW12040 （PW） has been used as an effective catalyst for the synthesis of thieno[2,3-d]pyrimidin-4（3H）-one derivatives. The present methodology offers several advantages, such as high yields, short reaction times, mild reaction condition and a recyclable catalyst with a very easy work up.     

[Cu4OCl6(DABCO)2]·0.5DABCO·4CH3OH (“MFU-5”): Modular synthesis of a zeolite-like metal-organic framework constructed from tetrahedral {Cu4OCl6} secondary building units and linear organic linkers

A novel metal-organic framework (MOF) based on a tetranuclear copper cluster and a linear organic ligand formulated as [Cu₄OCl₆(DABCO)₂]·0.5DABCO·4CH₃OH (denoted as MFU-5, MFU=Metal-Organic Framework, Ulm University; DABCO=1,4-diazabicyclo[2.2.2]octane), was prepared via solvothermal synthesis. In contrast with common MOF synthesis strategies, MFU-5 is assembled from pre-defined molecular secondary building units, i.e. {Cu₄OCl₆} moieties, which become the nodes of the coordination framework. The title compound was characterized by single crystal X-ray diffraction, variable temperature powder diffraction (VT-XRPD), thermal analysis, as well as IR- and UV/Vis spectroscopy. Crystal data for MFU-5: hexagonal, P6/mcc (no. 192), a=25.645(9), c=17.105(11) Å, V=9742(8) Å³, Z=12, 1690 structure factors, R[F²>2σ(F²)]=0.049. MFU-5 is a 3D metal-organic framework with 1D channels running along the c-axis hosting DABCO and methanol solvent molecules. The framework displays a zeolite-like structure constructed from mso cages, which represents the composite building units in the zeolites SSF, MSO and SZR. Two-fold interpenetration is observed between these building units. TG/DTA-MS and VT-XRPD characterization reveal a stepwise release of methanol and DABCO molecules upon heating, eventually resulting in a structural change into a non-porous material.