光促进下溴代烃在CH3OH/DMF体系中的羰基化反应

羰基化反应是有机合成中最重要的反应之一,其合成产品分别为醛、酮、酯、羧酸和酰胺等一系列化合物,可用作溶剂、增塑剂、润滑剂以及天然产物的替代品。卤代烷烃种类繁多,价格低廉,以其为底物进行羰基化反应,可以得到多种多样的羰基化合物。但常规羰基化反应往往需要高温(150-2     

光促进温和条件下烯烃与二氧化碳的羰基化反应

羰基化反应是有机合成化学中常用的方法之一,但常规的羰基化反应大多要求高温(150～200℃)、高压(10～20 M Pa)或使用贵金属催化剂(如钌、铑、铱等),并且C₁源多用一氧化碳^[1].开发和利用CO₂这一丰富的C₁资源,并最大限度地降低其排放量具有挑战意义.但CO₂活化比较困难,在通常条件下难以转化成其它化学品^[2].在光促进下的羰基化反应可克服上述困难,使反应在温和条件及非贵金属催化下完成,同时可用CO₂代替CO作为C₁源,因此这是一个对环境友好的工艺^[3].本文报道烯烃在光促进常温常压和非贵金属钴配合物催化下与二氧化碳的羰基化反应,同时通过¹³CO₂和¹³CH₃OH同位素实验,对反应产物的结构进行了分析.     

Photopromoted Methoxycarbonylation of Olefins Under Ambient Conditions in DMF

Photopromoted methoxycarbonylation of olefins with carbon monoxide can be carded out under ambient conditions with non-precious transition metal complexes (such as cobalt complexes) catalysts in DME The isotope experiments show that DMF is decomposed under irradiation and is conveniently used as a carbon monoxide source for the reaction.     

光促进温和条件下溴代烷烃与甲酸甲酯的羰基化反应

研究了光促进温和条件下,以甲酸甲酯为C1源,非贵金属钴盐、铜盐催化的溴代烷烃的羰基化反应.实验表明,在光促进下,钴盐、铜盐均可催化溴代烷烃与甲酸甲酯的羰基化反应,得到相应的羧酸甲酯.钴盐催化下,碱性添加物NaOAc对反应有很好的促进作用,直链溴代烷烃在反应中除了得到相应的正构酯外,还有少量异构酯生成;铜盐催化下,直链溴代烷烃在反应中主要生成相应的正构酯.机理研究表明,在光照下甲酸甲酯先分解为CO和CH3OH,再与溴代烷烃进行羰基化反应.     

A Convenient Method for Synthesis Methyl Ester of Naproxen

α-Arylpropionic acids are a class of nonsteroidal anti-inflammatory drugs with a substantial size of market. Ibuprofen and naproxen are the important members of this family. Since carbonylation catalyzed by transition metal complexes provides an environmentally benign process for their synthesis, there have been numerous patents and publications related to the carbonylation of alcohols and olefins to produce α-arylpropionic acids or their esters^[1-4]. We have studied the carbonylation of α-(6'-methoxy-2'-naphthyl) ethanol to methyl ester of naproxen using PVP-PdCl₂-CuCl₂/PPh₃ catalyst system. Good conversion and selectivity were obtained under mild conditions.     

Cobalt-catalyzed photopromoted carbonylation of chloroalkanes in the presence of KI

<正>The photopromoted carbonylation of chloroalkanes with carbon monoxide catalyzed by cobalt compounds[Co(OAc)_2,CoCl_2] in the presence of KI was carried out under ambient conditions.The results revealed that the catalytic activity of Co(OAc)_2 was higher than that of CoCl_2.A basic additive NaOAc was beneficial to the reaction.Interestingly,with NaOAc as an additive, Co(OAc)_2 and CoCl_2 exhibited similar catalytic activity.Preliminary work showed that the role of iodide ion was initially to form active iodoalkanes via substituting chloride ion in chloroalkanes in situ,and then,the carbonylation of iodoalkanes proceeded under irradiation.     

常温常压下光促进烯烃与一氧化碳的羰基化反应

 报道了烯烃（环己烯和1－辛烯）与一氧化碳通过光促进实现常温常压非贵金属（钴配合物）催化的羰基化反应．研究发现，以Co（OAc）2为催化剂时，不需要加入光敏剂丙酮就能发生反应；CoSalen，吡啶－2－羧酸钴和大环配合物［Co（14）4，11－diene－N4］I2是较好的催化剂，其催化活性比Co（OAc）2高．其中，吡啶－2－羧酸钴与Co（OAc）2相同，反应中不需要光敏剂存在，其选择性很高．通过氘代丙酮和氘代甲醇同位素实验，进一步证实了反应中双键异构的存在和副产物的分析结果．     

Photopromoted methoxycarbonylation of olefin with methyl formate by Co（OAc）2

The photopromoted methoxycarbonylation of olefin with methyl formate catalyzed by Co(OAc)2 at ambient conditions has been carried out.The results indicated that the reaction activity increased with the increasing temperature.Methyl formate decomposed into CO and CH_3OH firstly under irradiation,and then the methoxycarbonylation of olefin proceeded under catalysis of Co(OAc)_2. The mechanism of methyl formate participating in the methoxycarbonylation is verified by the IR analysis and the labeling experiments of CD_3OD and CH_3~(18)OH.     

Photopromoted carbonylation of bromobenzene under ambient conditions

The photopromoted carbonylation of bromobenzene with carbon monoxide catalyzed by inexpensive commercially available cobalt salts[Co(OAc)_2,CoCl_2]was carried out under ambient conditions.The results revealed that methyl benzoate was produced in the presence of basic additives(CH_3ONa,NaOAc or(n-C_4H_9)_3N).The catalytic activity of Co(OAc)_2was higher than that of CoCl_2.Furthermore,the activity of the carbonylation was greatly improved by addition of acetophenone,e.g.both the yield and selectivity of t...     

Methoxycarbonylation of olefins catalyzed by palladium(II) complexes containing naphthyl(diphenyl)phosphine ligands

Palladium(II) complexes containing phosphine donor ligands derived from naphthyl(diphenyl)phosphine were synthesized and characterized by NMR and elemental analysis. The complexes were studied as catalyst precursors in the methoxycarbonylation reaction of several aromatic and aliphatic olefins under mild conditions. The catalysts reported high chemoselectivities (over 96%) and regioselectivities between 44% and 93% for different olefins. The best results were obtained over a styrene substrate with 97% of conversion after 6 h of reaction, with high regioselectivity (93%). Kinetic studies permitted the determination of the rate law (v = k [substrate]^1.21±0.02 [catalyst]^0.94±0.11 [acid]^0.52±0.03 [MeOH]^0.53±0.05 [CO]^0.65±0.03) for methoxycarbonylation of styrene. Copyright © 2014 John Wiley & Sons, Ltd.     

XPS Spectra of K-Ru/MWNTs Catalysts for Ammonia Synthesis

Alkali metal and alkali oxide-promoted ruthenium has been found to be one of the most active catalysts for ammonia synthesis under atmospheric pressure^[1]. Recently, We found^[2] that the K-Ru/MWNTs catalyst showed very high activity for ammonia synthesis. It is suggested that the high activity is due to the special electronic and structural properties of the carbon nanotubes. Alkali and alkali oxide doped MWNTs have been reported to be more favorable for electronic transfer and hydrogen storage^[3]. In the ammonia synthesis,these properties may play important roles. In this study, K-Ru/MWNTs and Ru/MWNTs were prepared and characterized by XPS. We found that alkali oxide can improve the Ru dispersion similar to the classic catalysts for ammonia synthesis.     

Novel VPO Catalysts for n-Butane Oxidation to Maleic Anhydride:The Effects of Combined Moderators,Preparation Procedure and MCM-41 Supports

VPO catalysts are widely used in selective oxidation of n-butane into maleic anhydride (MA)^[1-2]. In the recent years, there is an obvious trend worldwide that the selectivity of a target product is more emphasized than the overall conversion, to decrease the undesired by-products. In this study, different approaches have been tried to generate more environmentally friendly VPO catalysts, with high MA selectivity and improved n-butane conversion. The moderated catalyst was prepared in aqueous phase^[3]. For comparison, the moderators were also introduced by impregnating the VPO precursor synthesized in organic medium. The supported VPO systems on the MCM-41 mesopore materials were prepared by employing the reaction of V₂O₅ with isobutanol in the presence of MCM-41 fine powder with different Si/Al ratios. The catalysts were evaluated at 385-425℃ and characterized by XRD, XPS and TPR etc.     

Hydrogen generation from methanol reforming under unprecedented mild conditions

A homogeneous catalyst [Cp^*Rh(NH₃)(H₂O)₂]³⁺ has been found for the clean conversion of methanol and water to hydrogen and carbon dioxide.The simple and easily available reaction steps can circumvent the formation of CO,therefore,making it possible to avoid inactivating catalysts and contaminating the hydrogen fuel.Different from conventional reforming method for hydrogen production,no additional alkaline or organic substances are required in this method.Valuable hydrogen can be obtained under ambient pressure at 70℃,corresponding TOF is 83.2 h^-1.This is an unprecedented success in reforming methanol to hydrogen.Effects of reaction conditions,such as reaction temperature,initial methanol concentration and the initial pH value of buffer solution on the hydrogen evolution are all systematically investigated.In a certain range,higher reaction temperature will accelerate reaction rate.The slightly acidic condition is conducive to rapid hydrogen production.These findings are of great significance to the present establishment of the carbon-neutral methanol economy.     

Dimeric Calix[4]resorcinarene-based Porous Organic Cages for CO2/CH4 Separation

Investigating gas separation by emerging porous organic cage(POC) solids is still on its initial stage. In this work, two novel [2+4] organic cages with distinguished structures have been prepared based on the Schiff-based condensation reaction between tetraformyl-functionalized calix[4]resorcinarene building blocks and xylylenediamine(XDA) isomers. Specifically, the use of para-position XDA affords lantern-shaped cage(CPOC-105) with a medium cavity of ca. 0.526 nm³, while the meta-position produces peanut-shaped structure(CPOC-106) with two small cavities of ca. 0.181 nm³. Both CPOC-105 and CPOC-106 exhibit high selectivity capture of CO₂ over CH₄ with calculated selectivity coefficients of 4.5 and 3.1, respectively, under ambient conditions, and are capable of separating CO₂/CH₄ mixtures by fixed-bed column breakthrough experiments.     

一氧化碳参与不饱和烃类化合物羰基化反应的研究进展

不饱和烃类化合物的羰基化反应是指在过渡金属催化剂存在条件下, 将一氧化碳(CO)分子以羰基的形式插入到烯烃(或者炔烃)与不同的亲核试剂中, 合成更高附加值化学品的转化过程. 本文综合评述了羰基化反应合成高附加值化学品的重要性, 介绍了几种不同类型的羰基化反应(氢甲酰化反应、 氢酯化反应、 氢酰胺化反应和氢羧基化反应)在发展新型催化剂体系及高效合成目标产物方面的研究进展, 并对羰基化反应存在的问题及未来发展方向和趋势进行了展望.     

MCM-41 Supported Nickel Catalysts for Carbon Dioxide Reforming of Methane

There has been an increasing interest in the conversion of methane and carbon dioxide into synthesis gas^[1]. High performance Ni-based catalysts have attracted much attention^[2-4]. In this study, MCM-41 supported nickel were used as catalysts for carbon dioxide reforming of methane. It is found that the obtained catalyst exhibited high activity for getting syngas with its ratio of unity.In contrast to the performance of other nickel-based catalysts; Ni/MCM-41 has higher conversion and yield at lower temperature. The effects of nickel loading, particle size, GHSV, and calcination temperature on catalytic activities were also investigated.     

Pre-reduced Activated Carbon-Supported Molybdenum-Based Catalysts for the Production of Mixed Alcohols from Synthesis Gas

Unsupported or supported Mo-based catalysts have been widely employed in petroleum industry, for hydrotreating^[1],and for the production of hydrocarbons^[2] and alcohols_[3] by hydrogenation of CO (or CO₂). Oxides, such as alumina, silica, silica-alumina, are commonly used as the supports for these purposes. Carbon-supported materials have been claimed to have potential advantages over oxide-supported ones, such as lower tendency of carbon deposition^[4], less dehydration and thus less secondary reactions. Here we present results on mixed alcohol synthesis over H₂-prereduced C-supported Mo-based catalysts.     

Improved Alkylation Technology with Solid Acid Material as Catalyst

Alkylation of isobutane with C3-C5 olefins has been practiced commercially since the 1940s. Indeed, alkylation which is mainly formed by multibranched paraffins,has a rather low vapor pressure, high octane numbers (RON and MON) and a low sensitive factor. In the past twelve years, about 20 alkylation plants using either HF or H₂SO₄ catalysts have been built in China^[1]. Concerns have been raised about the safety and environmental impact of the handing of the very large quantities of these liquid acids used in alkylation today and a great deal of time and money has been spent in the past 20 years in attempts to develop alkylation catalyst and process that are more environmentally friend than current industrial technology^[2]. To date,no process has been announced that seems to be of commercial interest, but two possible exceptions (Topöse process and UOP Alkylene process) are discussed in this paper. Many difficult technical challenges must be surmount in the next few years for a new solid catalyst alkylation process to be commercialized successfully.     

Enantioselective Hydroarylation of Olefins Using Palladium/Chiral Quinoline Oxazolines

Palladium-catalyzed arylation and alkenylation of olefins, known as the Heck reaction, is one of the most efficient catalytic methods for carbon-carbon bond formation in organic synthesis^[1]. During the last decade, asymmetric Heck reactions have attracted great attention, and a number of highly enantioselective chiral ligands have been developed to enhance chiral discrimination in these reactions^[2]. However, asymmetric Heck-type hydroarylations of olefins, addition of aryl halides or triflates to carbon-carbon double bonds, have not been well studied. In 1991, Brunner reported an asymmetric hydroarylation of norbornene and norbornadiene with aryl iodides using chiral bisphosphine ligands, and around 40% ee was achieved^[3]. Later on, Achiwa reached around 70% ee in the asymmetric hydroarylation of norbornene with phenyl triflate by using chiral P-N ligands^[4,5]. Herein, we wish to describe our investigations on chiral quinolinyl-oxazoline ligands that provide the first examples of efficient bisnitrogen ligands in Heck-type hydroarylation and the application of this reaction in the asymmetric synthesis of Epibatidine.     

光促进温和条件下烯烃的氢甲酯化反应

在紫外光照射下烯烃的氢甲酯化反应能在常温常压条件下完成,系统地研究了不同钴盐催化剂的反应规律及酸碱性对反应的影响.发现醋酸钠可大大提高反应的选择性及产率,提出了醋酸钠作用的初步机理,即对反应体系酸碱性的调节及醋酸钠与催化剂的相互作用.