乙酸促进邻甲基苯磺酸铜选择性催化醛与乙酸酐合成偕二乙酸酯反应

在室温无溶剂条件下,考察了乙酸促进邻甲基苯磺酸铜催化一系列芳香醛或脂肪醛与乙酸酐生成相应的偕二乙酸酯反应.结果表明,在乙酸存在条件下,邻甲基苯磺酸铜用量仅需占醛的0.3%(摩尔比)就能使反应在较短时间内完成.反应结束后,邻甲基苯磺酸铜经简单相分离可多次重复使用,催化活性无明显下降.     

对氨基苯磺酸铜/乙酸催化醇和酚的四氢吡喃化反应(英文)

考察了对氨基苯磺酸盐(铜、镍、锌、钴、铝、镉、锰、镧、亚钸、谱、钕、钐、铕、铽、镝、钬、铒)和布朗斯特酸在醇和酚的四氢吡喃化反应中的协同催化效应.其中,对氨基苯磺酸铜与乙酸的协同催化效果最好.室温无溶剂条件下,各种醇和酚的四氢吡喃化反应产率均较高.反应结束后,对氨基苯磺酸铜重复使用6次,催化活性无明显下降.     

硫酸钴-乙酸协同催化醇和酚的四氢吡喃化反应

报道了硫酸钴-乙酸在室温、无溶剂条件下催化醇和酚的四氢吡喃化反应。硫酸钴-乙酸作为协同催化体系,二者缺一不可。与传统催化剂相比,新催化体系的催化活性最好．反应结束后,硫酸钴经简单相分离可回收,重复使用多次催化活性无明显下降。提出了可能的催化反应机理．     

无溶剂条件下"一锅法"催化合成胺基烷基萘酚衍生物

无溶剂条件下,邻甲基苯磺酸铜可有效催化2-萘酚、醛和胺三组分"一锅法"合成胺基烷基萘酚衍生物.考察了溶剂条件及催化剂用量对产率的影响.经催化剂循环研究,该催化剂重复使用4次仍保持较高活性.产物的结构通过熔点,IR,1HNMR,13CNMR,质谱和元素分析进行测定和结构表征.同时给出了该反应可能的反应机理.     

过渡金属甲基磺酸盐催化醇的四氢吡喃化反应

以过渡金属甲基磺酸盐［Mn(CH₃SO₃)₂·2H₂O, Cu(CH₃SO₃)₂·4H₂O, Co(CH₃SO₃)₂·4H₂O和Zn(CH₃SO₃)₂·4H₂O］为催化剂,在室温条件下催化醇的四氢吡喃化反应,并对反应条件进行了优化。结果表明：当醇用量为30 mmol,醇和3,4-二氢吡喃摩尔比为1.0 ：1.1,甲基磺酸盐用量为1 mmol,二氯甲烷20 mL时,可高效催化醇的四氢吡喃化反应。与路易斯酸催化活性相比,过渡金属甲基磺酸盐催化醇的四氢吡喃化反应效果最好,催化酚的效果较差。用Mn(CH₃SO₃)₂·2H₂O和Cu(CH₃SO₃)₂·4H₂O催化正丁醇的四氢吡喃化反应,重复使用5次,收率分别为89%和92%。     

温和条件下邻甲基苯磺酸铜催化三组分“一锅法”合成喹唑啉-4(3H)-酮衍生物

室温、无溶剂条件下,邻甲基苯磺酸铜可有效催化邻氨基苯甲酸、胺和原甲酸酯三组分"一锅法"合成喹唑啉-4(3H)-酮衍生物.考察了原料配比及催化剂用量对产率的影响.经催化剂循环研究,催化活性无明显变化.产物的结构通过熔点,IR,1HNMR和元素分析进行测定和结构表征.同时给出了可能的反应机理.     

苯磺酸铜-乙酸催化醛的双乙酰化反应

苯磺酸铜-乙酸共催化体系于室温催化一系列醛的双乙酰化反应,合成了相应的1,1-二乙酸酯(2),产率59%～97%.2的结构经1H NMR和IR表征.     

改性活性炭催化羟基的四氢吡喃化保护及脱保护反应研究

以浓硫酸改性的活性炭为催化剂,催化二氢吡喃对醇(酚)羟基的保护,使其形成相应的四氢吡喃醚(2):2在催化剂作用下能顺利的脱除保护基团.     

RANEY©Ni催化三乙酸内酯氢转移反应的研究

基于氢转移原理,以醇为氢源,将RANEY~? Ni催化剂用于三乙酸内脂(TAL)的加氢反应.通过筛选醇溶剂等条件,在氮气气氛中,以异丙醇为氢源,50℃下反应10 h可高选择性地制得89%的4-羟基-6-甲基四氢-2-吡喃酮.循环稳定性实验和氨基酸毒化实验证实RANEY~? Ni催化剂在该反应中优异的稳定性.     

2-甲基-4-甲氧基苯基苯胺的合成

邻硝基甲苯在甲醇、乙酸和硫酸混合溶液中, 在Pt/C的催化下发生氢化和Bamberger重排生成2-甲基-4-甲氧基苯胺. 后者在Pd/C的存在下以苯酚为反应介质与环已酮缩合生成2-甲基-4-甲氧基苯基苯胺, 反应总产率63.0%. 文中给出了产物与中间产物的核磁共振氢谱和质谱, 同时讨论了影响反应的因素.     

邻甲基苯磺酸铜催化"一锅法"合成3,4-二氢嘧啶-2(1H)-酮

二氢嘧啶酮(DHPMs)及其衍生物具有广泛的生物活性,如抗病毒、抗肿瘤、抗癌、抗高血压及消炎等作用[1].此外,DHPMs及其衍生物作为钙通道阻滞剂、α1a-对抗剂和神经肽Y的对抗剂,显示出良好的药理活性[2].更重要的是,最近几种含二氢嘧啶酮-5-羧酸盐的海洋生物碱被成功分离出来,并表现出重要的生物学性质[3],某些可以阻止HIVgp-120-CD4键的形成,是一种潜在的HIV抑制剂[4].因此,对DHPMs及其衍生物的研究成为生物活性有机杂环化合物的研究热点之一.     

醋酸溶液中Pd-CuPc/Y催化甲烷选择氧化制甲醇

以氯化铜、钼酸铵、苯酐、氯化铵、尿素和NaY分子筛为原料,采用苯酐-尿素法制备了酞菁铜/分子筛复合物CuPc/Y.采用等体积浸渍法将金属钯担载在CuPc/Y上制备了Pd-CuPc/Y催化剂,并在醋酸水溶液中考察了其催化甲烷选择氧化合成甲醇反应的性能,结果表明,催化性能与反应温度、溶剂中CH₃COOH与H₂O的混合比例、对苯醌用量、反应时间等因素有关,在0.5%Pd-0.5%CuPc/Y添加量0.5 g、CH₃COOH与H₂O体积比4∶1、对苯醌用量1 000 μmol、反应时间3 h、反应温度150 ℃的条件下,甲醇的最佳生成量为1 840 μmol.Pd-CuPc/Y催化剂可以多次循环使用,但由于催化剂流失和催化剂表面的钯粒子聚集的原因,循环使用后的催化剂催化活性有所下降.Pd-CuPc/Y在醋酸溶液中催化甲烷选择氧化合成甲醇是亲电取代反应和活性氧物种氧化共同作用的结果.     

几种磺酸铜盐的合成、表征及其催化氯乙酸酯化反应性能比较

酯化反应广泛应用于有机、生物有机以及相关的精细化学品的合成。在各类催化剂中,Lewis酸兼有均相和多相催化剂的优点。但是部分Lewis酸仍存在一些不足,如铪盐和锆盐虽然具有较高的催化活性,     

A Fluxional Copper Acetylide Cluster in CuAAC Catalysis

A molecularly defined copper acetylide cluster with ancillary N‐heterocyclic carbene (NHC) ligands was prepared under acidic reaction conditions. This cluster is the first molecular copper acetylide complex that features high activity in copper‐catalyzed azide–alkyne cycloadditions (CuAAC) with added acetic acid even at ?5 °C. Ethyl propiolate protonates the acetate ligands of the dinuclear precursor complex to release acetic acid and replaces one out of four ancillary ligands. Two copper(I) ions are thereby liberated to form the core of a yellow dicationic C₂‐symmetric hexa‐NHC octacopper hexaacetylide cluster. Coalescence phenomena in low‐temperature NMR experiments reveal fluxionality that leads to the facile interconversion of all of the NHC and acetylide positions. Kinetic investigations provide insight into the influence of copper acetylide coordination modes and the acetic acid on catalytic activity. The interdependence of “click” activity and copper acetylide aggregation beyond dinuclear intermediates adds a new dimension of complexity to our mechanistic understanding of the CuAAC reaction.     

铌酸催化液相合成乙酸乙酯

报道了铌酸催化乙醇与乙酸的液相酯化反应考察了反应温度、催化剂用量、酸醇比、反应时间对产品乙酸乙酯经的影响。在优化条件下,产品收率棕达８８．０％,选择性为１００％,同时我们采用自制间式反应,对催化剂的稳定性进行了考察,发现铌酸在该实验条件下,能保持较高的稳定性和较高的催化活性。     

Effect of Preparation Conditions on the Stability of Pt/Al2O3 Catalysts in Methane Combustion

Alumina supported platinum catalysts were prepared by sol-gel method using aluminum-sec-butoxide, platinum acetylacetonate and sec-butanol. Various gelation process were performed either by the help of a gelation agent (water or acetic acid) or by a slow condensation without hydrolysis source. The textural and the structural study of the catalysts using the nitrogen physical adsorption and the hydrogen chemisorption showed that the BET surface area and the metal dispersion varied when the hydrolysis and the gelation processes were modified. The catalytic activities for methane combustion performed on the fresh and aged catalysts were correlated to the metal dispersion values. In addition the catalytic activity loss under reaction mixture seemed to be caused by the metal dispersion decrease. When the catalysts were aged under the reaction mixture at 600°C for 72 h, a BET surface area decrease and a metallic surface area loss were observed. The resistance to sintering observed to be dependant on the hydrolysis and the gelation processes was in favor of the catalyst prepared by acetic acid.     

Production of citronellyl acetate in a fed-batch system using immobilized lipase

Several reports exist in the literature citing the decrease in conversion rates of organic-phase catalytic synthesis reactions when acetic acid is present as a reaction component. This inhibition is thought to result from damage to either the hydration layer-protein interaction or the overall enzyme structure. In this work, the inhibitory effect of acetic acid on lipase enzyme activity was ameliorated by conducting syntheses under acetic acid-limiting conditions in a fed-batch system, resulting in higher product yields. Periodic additions of acetic acid at levels of 40 mM or less gave maximum yields of 65% conversion for the reaction of citronellol and acetic acid to form citronellyl acetate. The enzyme used was a fungal lipase fromMucor miehei, and was immobilized on macroporous synthetic resin (a Novo lipozyme Novo Nordisk, Denmark). These results represent a fourfold improvement over batch runs reported in the literature for direct esterification of terpene alcohol with acetic acid using lipozyme as a catalytic agent.