无配体钯催化乙醇水溶液中芳基三氟硼酸钾的Suzuki反应

发展了一个无配体钯催化芳基三氟硼酸钾的Suzuki反应体系.该体系在空气条件下,以醋酸钯为催化剂,1equiv.的无水碳酸钾为碱,在乙醇水溶液中可高效催化卤代芳烃或杂环卤代芳烃与芳基三氟硼酸钾的Suzuki反应,周转频率(TOF)值最高达4656 h~(-1),且该体系还适用于三苯胺衍生物的合成.透射电镜分析结果及汞中毒实验证明该体系的实际催化物质为原位生成的纳米钯粒子.     

Pd2(dba)3/Et3N高效催化碘代芳烃Sonogashira 羰化偶联反应研究

在甲苯溶剂中,以价廉易得的Pd2(dba)3作为催化剂,以三乙胺作为碱,在无膦体系中成功实现了碘代芳烃和端位炔烃的Sonogashira羰化偶联反应,最高收率达95%,且该催化体系具有较好的底物适应性.该研究发展了α,β-不饱和炔酮类化合物的高效合成方法.     

钯/碳高效绿色催化Suzuki交叉偶联反应

开发了一个以钯/碳为催化剂高效绿色催化Suzuki反应制备联苯类化合物的新方法.该体系以环境友好的聚乙二醇400的水溶液为反应溶剂,加入离子液体1-甲基-3-丁基咪唑双三氟甲磺酰亚胺盐,可高效催化溴代芳烃与芳基硼酸的Suzuki交叉偶联反应,并且催化剂可以循环利用4次而催化效率没有明显降低.     

PEG1000-DIL/甲苯温控两相体系中硝基芳烃的还原反应

研究了PEG1000-DIL/甲苯温控体系中硝基芳烃的还原反应.考察了催化加氢、水合肼/FeCl3.6H2O和水合肼/Fe5HO8.4H2O等3种还原体系,发现水合肼/Fe5HO8.4H2O在PEG1000-DIL/甲苯温控体系中具有很高的催化活性,将其用于12种硝基芳烃的还原反应,产率最高可达99%.该催化体系重复使用3次后产率无明显变化,用于卤代硝基苯类化合物的还原可以有效防止脱卤副反应的发生.     

无配体Cu2O纳米线催化C—N/C—O偶联反应

介绍了由TiO2纳米阵列管上负载Cu2O纳米线,制备新型纳米催化剂Cu2O/TiO2NTs的方法.应用该新型催化剂,研究了其对卤代芳烃的C—N,C—O偶联反应的催化作用,结果表明Cu2O/TiO2NTs不仅能很好地催化溴代芳烃与氮/氧亲核试剂的反应,而且可顺利催化氯代芳烃的反应,得到中等及优良的产率.催化剂循环使用试验证实,催化剂在该体系中能被回收利用5次收率基本稳定.     

Pd2dba3高效催化碘代芳烃的双羰化反应合成α-酮酰胺

以高效、廉价易得的Pd2dba3作为催化剂,成功实现了碘代芳烃的双羰化反应,得到的α-酮酰胺最高分离收率达90%.该催化体系对于不同取代基的碘代芳烃和仲胺都具有广泛的底物适应性.     

低温Suzuki反应合成联苯及三联苯化合物

发展了一个低温下无配体钯催化溴代芳烃与芳基硼酸的Suzuki反应体系。该体系以醋酸钯为催化剂,无水碳酸钾为碱,乙醇水溶液为溶剂,无需加入任何配体,在0oC下即可高效催化溴代芳烃与芳基硼酸的Suzuki反应;反应的底物容忍性好,产品分离收率最高达97%。以溴代芳基N-甲基亚氨基二乙酸硼酸酯为砌块分子,通过调控反应温度,实现了砌块分子选择性Suzuki反应,从而一锅合成了不对称三联苯化合物,产品收率最高为81%。     

基于简单高效钯纳米粒子催化Suzuki偶联反应的研究

一种简单、高效的钯纳米粒子催化体系被用于Suzuki偶联反应中.该催化体系对含各种官能团的卤代芳烃和芳基硼酸都表现出了非常高的催化活性.当用对硝基溴苯作底物时,在催化剂用量低至0.001 mol%时转化数能达到90000,这也证实了该催化体系有比较好的稳定性和较长的寿命.     

纳米钯催化的高效Suzuki偶联反应

开发了一种使用Al2O3作载体,由四三苯基膦钯制备的纳米钯催化剂催化的高效绿色Suzuki反应来合成联苯类化合物的方法.该反应体系以DMF和H2O的混合体系作反应溶剂,在空气中于25~90℃下,催化剂可高效催化卤代芳烃与芳基硼酸的Suzuki偶联反应,所有考察的反应底物都给出很高的收率,并且催化剂循环利用6次后,其催化活性和反应收率都没有明显降低.     

碘化亚铜/亚磷酸三乙酯催化碘代芳烃和末端炔烃的偶联反应

以廉价的亚磷酸三乙酯为配体,首次用于Cu催化的碘代芳烃和末端炔烃的偶联反应,考察了不同Cu盐、金属纯度、碱和催化剂用量等条件对反应性能的影响.结果表明,当以高纯度的CuI (99.999％)为铜源,催化剂用量为5mol％时,在KOH作用下,该催化体系成功催化了一系列碘代芳烃和末端炔烃的反应,表现出良好的催化活性,此外,...     

Bimetallic Au/Pd catalyzed aerobic oxidation of alcohols in the poly(ethylene glycol)/CO2 system

Bimetallic Au/Pd nanoparticles were prepared and used to catalyze oxidation of alcohols in the poly(ethylene glycol) (PEG)/CO₂ biphasic system using O₂ as the oxidant without adding any base. The catalytic activity of Au/Pd bimetal with different mole ratios was studied using benzyl alcohol as the substrate. It was found that bimetallic Au/Pd nanoparticles with Au:Pd=1:3.5 had higher catalytic activity than monometallic Au, Pd and the bimetallic Au/Pd nanoparticles with other molar ratios. The effect of CO₂ pressure on the oxidation of benzyl alcohol and 1-phenylethanol in PEG/CO₂ was investigated. It was demonstrated that CO₂ pressure could be used to tune the conversion and selectivity of the reactions effectively. α,β,-Unsaturated alcohols were also studied and found to be more reactive than benzyl alcohol and 1-phenylethanol. Recycling experiments showed that the Au/Pd/PEG/CO₂ catalytic system could be recycled at least four times without reducing the activity. In addition, the catalytic system is clean and the products can be separated easily.     

Pd‐Colloids‐Catalyzed/Ag2O‐Oxidized General and Selective Esterification of Benzylic Alcohols

Palladium colloids obtained from the degradation of Hermann–Beller palladacycle proved to be an efficient catalytic system in combination with silver oxide as a selective oxidant for the oxidative esterification of differently substituted benzyl alcohols in MeOH as solvent. Excellent reactivity exhibited by the catalytic system also allowed the alcoholic coupling partner to be changed from MeOH to a wide range of alcohols having diverse functionalities. The mildness of the developed protocol also made it possible to employ propargyl alcohol as the coupling partner without any observation of any interference of the terminal alkyne. Selective oxidative coupling of a primary alcoholic functional group over secondary in the case of glycols and glycerols was also made possible using the developed catalyst system. To test the relevancy of Pd/Ag combined catalysis mixed Pd/Ag colloids were synthesized, characterized by TEM, XRD and XPS and applied to oxidative‐esterification successfully.     

Agglomerated Pd Catalysts and Their Applications in Hydrogen Production from Formic Acid Decomposition at Room Temperature

Agglomerated Pd catalysts with the nano-porous structure were simply prepared by one-step reduction reaction without using any stabilizer. The Pd catalysts show a high catalytic activity for the decomposition of formic acid at room temperature. Among all the Pd catalysts tested, the Pd_Mg catalyst exhibits the highest catalytic activity. Moreover, the breakthrough of the advanced catalysts is that the above agglomerated Pd catalysts can be easily separated from the liquid system to control the catalytic reaction at any time, which may further promote the practical application of formic acid as a H₂ storage material.     

水相中钯催化碘代芳烃Ullmann偶联反应研究

研究了吸电子基团的贫电碘代芳烃的Ullmann偶联反应,该反应使用Pd(OAc)2为催化剂,K2CO3为添加剂,以丙酮-水混合液为溶剂,不需要添加额外的还原剂,收率为55-87%。在通过了一系列的试验后,可以认为该反应中的溶剂及碱没有起还原作用,而是碘代芳烃自身作为还原剂,完成整个催化反应的,并首次提出了一种不需要外加还原剂的Pd(II)/Pd(IV)/Pd(II)的催化循环机理。     

Oxygen-promoted Pd/C-catalyzed Suzuki–Miyaura reaction of potassium aryltrifluoroborates

A simple and highly efficient protocol has been developed for the Pd/C-catalyzed ligand-free Suzuki–Miyaura reaction of potassium aryltrifluoroborates. In this catalytic system, the results demonstrate that oxygen plays a positive role in the cross-coupling reaction. In addition, this catalytic system could be successfully applied to synthesize biaryl compounds containing a carbazole moiety and the catalyst was recycled seven times without significant loss of catalytic activity.     

Pd基无涂层整体式催化剂上甲苯催化燃烧净化研究

采用化学镀法在堇青石蜂窝陶瓷基体上制备了Pd基无涂层整体式催化剂Pd/cord,并对其在甲苯催化燃烧净化反应中的催化性能进行了研究.结果表明,Pd/cord催化剂在钯负载量较低(如为0.24％)时,即可使甲苯从201℃起燃后,突跃到226℃完全转化,表现出良好的甲苯催化燃烧净化性能.该类催化剂在空速6000h-1 ～4...     

Recyclable and reusable Pd(OAc)2/DABCO/PEG-400 system for Suzuki-Miyaura cross-coupling reaction

[reaction: see text] A stable and efficient Pd(OAc)2/DABCO (triethylenediamine) catalytic system for Suzuki-Miyaura cross-coupling reaction has been developed. In the presence of Pd(OAc)2 and DABCO, coupling of aryl halides with arylboronic acids was carried out smoothly to afford good to excellent yields and high turnover numbers (TONs) (the maximal TONs were up to 960,000 for the reaction of 1-iodo-4-nitrobenzene with phenylboronic acid) using PEG-400 as the solvent. Moreover, the Pd(OAc)2/DABCO/PEG-400 system could be recycled and reused five times without any loss of catalytic activity for aryl iodides and bromides.     

Pd（OAc）2／FePc催化环己烯氧化合成环己酮的研究

考察了几种Ｆｅ－大环配合物与Ｐｄ（ＯＡｃ）２组成的双组分催化体系，在乙腈酸性水溶液中环己烯经合成环己酮的催化活性，实验结果表明，其中以酞菁失（ＦｅＰｃ）与Ｐｄ（ＯＡｃ）２组成的催化体系活性最高，而ＦｅＴＰＰＣｌ与Ｐｄ（ＯＡｃ）２催化体系，虽然催化活性较高，但催化剂的稳定性较低，各种因素对Ｐｄ（ＯＡｃ）２／ＦｅＰｃ催化活催化影响的研究结果指出，在无水和酸存在的非水溶液中，Ｐｄ（ＯＡｃ）２／ＦｅＰｃ对     

Argon glow discharge plasma‐reduced palladium nanoparticles supported on activated carbon for Suzuki and Heck coupling reactions

Palladium nanoparticles supported on activated carbon were prepared by argon glow discharge plasma reduction (Pd/C‐P) without any chemical reducing agents and protective agents. The as‐prepared Pd/C‐P catalyst was characterized using nitrogen adsorption–desorption, X‐ray diffraction and transmission electron microscopy analyses. The results showed that the palladium nanoparticles reduced by plasma are well dispersed with a smaller particle size than commercial Pd/C. Pd/C‐P exhibited a high catalytic activity in Suzuki and Heck coupling reactions. Moreover, there was no obvious loss of catalytic activity even after eight repeated cycles, showing good reactivity and recyclability.     

Mesoporous Silica MCM‐41 Supported N‐Heterocyclic Carbene‐Pd Complex for Heck and Sonogashira Coupling Reactions

Heterocyclic carbene‐Pd complex was anchored onto the mesoporous silica MCM‐41 which exhibits high catalytic activity in Heck reaction under phosphine free reaction conditions for the reaction of iodo/bromoarenes with olefinic compounds such as butyl acrylate, isopropyl acrylate and styrene. This catalytic system also showed high activity for Sonogashira coupling reaction of various aryl halides under copper, phosphine and solvent‐free reaction conditions. The air and thermally stable catalyst were reused several times without significant loss of its activity. High efficiency of the catalyst along with its recycling ability and the rather low Pd‐loading demonstrated in both Heck and Sonogashira coupling reactions are the merits of the presented catalyst system.