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Polymer (fiber)-supported palladium catalyst containing imidazolinyl rings and its application to the Heck reaction 总被引:1,自引:0,他引:1
A polymer (fiber)-supported palladium catalyst was synthesized simply from commercially available polyacrylonitrile(PAN) fiber. Its high activity and selectivity for Heck reactions were measured; its activity remained unchanged after being recycled 20 times. 相似文献
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We designed and synthesized a novel catalyst consisting of ordered mesoporous silica (SBA-15) functionalized with bis(thiourea) (BTU) linker. The regular and unique pore channels of BTU-SBA-15 ensure proper control of the size and homogeneous distribution of palladium nanoparticles. The physiochemical properties of the hybrid Pd@BTU-SBA-15 pre-catalyst were investigated using various techniques. The proposed catalyst is found to be very active, reusable, stable and scalable, and has excellent reactivity and selectivity for Suzuki and Heck coupling reactions under very mild and sustainable reaction conditions. 相似文献
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Preparation of siloxene nanosheet‐supported palladium as sustainable catalyst for Mizoroki–Heck reaction 下载免费PDF全文
Siloxene nanosheets were successfully modified with palladium nanoparticles by reducing palladium chloride with hydrazine hydrate. The palladium nanoparticles–siloxene nanosheets as a catalyst for the Mizoroki–Heck reaction exhibited high activity, recoverability and stability. The structural morphology of the catalyst was investigated using transmission electron microscopy. High efficiency of the catalyst was proved in the Mizoroki–Heck reaction after five catalytic recycles. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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The guanidine‐functionalized resin‐supported Pd(0) catalyst [GDR·Pd(0)] is highly active in Heck reaction of aryl bromides with acrylic acid or styrene without the need to exclude air. The catalyst can be recycled at least 9 times without significant loss of activity in N‐methyl‐2‐pyrrolidone at 140 °C. The Heck reaction proceeds homogeneously with dissolved palladium species and the dissolved active palladium species can redeposit onto the surface of catalyst in the reaction. The XRD peak shifting of Pd phases in the catalyst provides the evidence for the re‐deposition of the active palladium species. 相似文献
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A novel SBA-15-functionalized TEMPO confined ionic liquid [BMIm]Br was found to be a highly efficient and recyclable catalyst system for the transition-metal-free aerobic oxidation of a wide range of structurally diverse alcohols. Thanks to the strong physical confinement of the ionic liquid inside the mesochannels of SBA-15-supported TEMPO, the resulting solid catalyst showed improved selectivity in the aerobic oxidation of allylic alcohols. The catalyst can be recovered and re-used for at least 11 reaction runs without significant loss of either activity or confined IL. 相似文献
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SBA-15负载Pd催化剂的制备及其在Heck反应中的应用研究 总被引:2,自引:0,他引:2
利用水热反应制备了表面离子液体功能化的SBA-15介孔材料,在丙酮溶液中与氯化钯反应,然后使用水合肼在乙醇中还原.测试了这种催化剂在Mizoroki-Heck反应中的催化活性.与直接负载在SBA-15上的钯催化剂相比,这种表面修饰的介孔SBA-15负载催化剂表现出更高的催化活性、可回收性和反应稳定性.氮气吸脱附实验和小角XRD衍射实验表明,在合成中,材料的介孔性能并没有被破坏.透视电镜也表征了该材料的表面形貌.最后,Mizoroki-Heck反应表明该催化剂具有很高的催化活性,且循环五次后,其催化活性降低并不明显. 相似文献
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Silica–acetylacetone‐supported palladium nanoparticles as an efficient and reusable catalyst in the Heck–Mizoroki C–C cross‐coupling reaction 下载免费PDF全文
The preparation of palladium nanoparticles supported on acetylacetone‐modified silica gel and their catalytic application for Heck olefination of aryl halides were investigated. The catalyst was characterized using X‐ray diffraction, X‐ray photoelectron spectroscopy, and transmission and scanning electron microscopies. The supported palladium nanoparticles are demonstrated to be a highly active and reusable catalyst for the Heck reaction. Several reaction parameters, including type and amount of solvent and base, were evaluated. The heterogeneity of the catalytic system was investigated with results indicating that there is a slight palladium leaching into the reaction solution under the applied reaction conditions. Despite this metal leaching, the catalyst can be reused nine times without significant loss of catalytic activity. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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The ethylenediamine-functionalized resin-supported Pd(0)complex was prepared from PdCl_2 and ethylenedia-mine-functionalized chloromethylated polystyrene,followed by reduction with KBH_4.The complex was character-ized by FT-IR,XRD,BET,SEM and EDS.The resin-supported catalyst exhibited high catalytic activity in theHeck reaction and could be reused up to 17 times in NMP or 16 times in DMF at 90 ℃ in the Heck reaction of io-dobenzene with acrylic acid.The leaching investigation disclosed that the palladium leaching was caused by the in-teraction of iodobenzene with the metal Pd(0)on supported catalyst.The leached palladium species in filtrate wasvery stable and could be reused five times after the solid catalyst was filtered off.A cross-transfer test in recyclingin the presence of additional carbon disclosed that the soluble leached palladium species had much higher catalyticactivity than supported and/or adsorbed palladium in solid-solution heterogeneous Heck reaction. 相似文献
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磁性纳米颗粒负载钯催化剂对Heck反应的催化活性 总被引:2,自引:0,他引:2
采用水热法合成了碳包埋磁性纳米复合颗粒C/(Au@Fe),并以之为载体制备了纳米钯催化剂,利用透射电镜、X射线光电子能谱和振动样品磁强计等手段对催化剂进行了表征,评价了催化剂对Heck反应的催化活性.结果表明,催化剂的平均粒径约为300nm,表面覆盖着一层粒径为12nm的钯颗粒,整个催化剂呈现超顺磁性.对于碘代苯与丙烯酸之间的Heck反应,在乙酸钠或三乙胺碱性条件下反应4h,碘代苯转化率可达95%以上.催化剂重复使用10次时仍可保持很高的催化活性(碘代苯转化率88%).对于其他不同反应底物之间的Heck反应,催化剂同样显示有较高的催化活性.催化剂可稳定分散于反应体系中,并可在外磁场作用下快速与反应体系分离. 相似文献
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以介孔氧化硅(SBA-15)为载体, 采用超声辅助(NH4)2RuCl6浸渍和BH4-还原法制备了负载型Ru-B催化剂, 并通过X射线衍射、X光电子能谱、差示扫描量热法和透射电子显微等技术表征了该催化剂.结果表明, 所制得的Ru-B-X/SBA-15催化剂具有非晶态合金结构, 且Ru-B颗粒高分散在SBA-15的孔道中.在液相麦芽糖加氢反应中, 与采用RuCl3为金属源制得的Ru-B-C/SBA-15相比, Ru-B-X/SBA-15催化剂具有更高的活性, 是非负载型Ru-B-C催化剂的7倍以上, 且能重复套用11次而未发生显著的失活. 相似文献
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In the present study, the modification of a mesoporous organosilica nanocomposite SBA-15 (Santa Barbara Amorphous 15) was carried out in two steps, first through the surface functionalization of SBA-Pr-NH2 with 2-chloroquinoline-3-carbaldehyde to form SBA-Pr-NCQ, and then through a post-modification process with palladium ions. The target nanocompound structure of SBA-Pr-NCQ-Pd was characterized by different techniques (thermogravimetric analysis, X-ray diffraction, scanning electron microscopy, Energy-dispersive X-ray spectroscopy (EDX), and Fourier transform infrared spectroscopy). The catalytic performance of the porous inorganic–organic hybrid nanocomposite (SBA-Pr-NCQ-Pd) in one of the most important carbon–carbon bond-forming processes, the Mizoroki–Heck coupling reaction of aryl halides and methacrylate in water/ethanol media, was examined. Compared to previous reports, this protocol afforded some advantages, such as high yields of products, short reaction times, catalyst stability without leaching, simple methodology, easy workup, and greener conditions. Also, the nanocatalyst can be easily separated from the reaction mixture and reused several times without a significant decrease in activity and promises economic as well as environmental benefits. 相似文献
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[reaction: see text] Ligand-free Pd(OAc)(2) can be used as a catalyst in the Heck reaction of aryl bromides as long as the amount of catalyst is kept between 0.01 and 0.1 mol %. At higher concentrations palladium black forms and the reaction stops. The actual catalyst is monomeric. Palladacycles merely serve as a source of ligand-free palladium in Heck reactions of aryl bromides. 相似文献
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无配体Pd/LDH-F催化剂在Heck和Suzuki反应中的应用 总被引:1,自引:0,他引:1
以氟离子插层的水滑石LDH-F为载体,用逐滴浸渍法制备了新型Pd/LDH-F催化剂,并用其催化溴代芳烃的Heck和Suzuki偶联反应. 用X射线衍射表征了催化剂的晶相,以等离子体发射光谱测定了溶剂中钯的流失量. 结果表明,对于Heck反应,在无配体存在和低钯用量(Pd/溴代芳烃摩尔比为0.001)的情况下, Pd/LDH-F的催化性能优于其它载体负载的Pd催化剂,显示出很高的催化活性和选择性. 在140 ℃和12 h的条件下, Pd/LDH-F催化溴苯与苯乙烯Heck反应产物的收率可达86%, 反应后催化剂经过分离,可循环使用四次其催化活性基本不变. 在DMF/水摩尔比为0.5的混合溶剂中,在室温和3 h 的条件下, Pd/LDH-F (Pd/溴代芳烃摩尔比为0.005)催化溴苯与苯基硼酸盐的Suzuki反应中,目标产物收率为99%. 相似文献
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Sanjay Srivastava Pravakar Mohanty Jigisha K. Parikh Ajay K. Dalai S. S. Amritphale Anup K. Khare 《催化学报》2015,(7):933-942
Cr-free bi-metallic SBA-15-supported Co–Cu catalysts were examined in the conversion of bio-mass-derived α-, β-unsaturated aldehyde (furfural) to value-added chemical furfuryl alcohol (FOL). Co–Cu/SBA-15 catalysts with a fixed Cu loading of 10 wt% and varying Co loadings (2.5, 5, and 10 wt%) were prepared by the impregnation method. The catalysts were characterized by X-ray dif-fraction, N2 sorption, H2 temperature-programmed reduction, scanning electron microscopy, ener-gy-dispersive X-ray spectroscopy, high-resolution transmission electron microscopy, CO chemi-sorption, and inductively coupled plasma mass spectrometry. The influence of different reaction parameters such as temperature, pressure, catalyst dosage, and furfural concentration on the cata-lyst performance was evaluated. Relative to catalysts supported on amorphous silica, the current SBA-15-supported Co–Cu catalysts displayed higher performance, attaining a furfural conversion of 99% and furfuryl alcohol selectivity of 80%. The catalytic reactions were conducted in a 100-mL autoclave at 170 °C and 2 MPa H2 pressure for 4 h. 相似文献
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Mansur B. Ibrahim Rami Suleiman Mohammed Fettouhi Bassam El Ali 《Transition Metal Chemistry》2017,42(1):1-8
A palladium(II)-bis(oxazoline) complex supported on silica (Pd-BOX-Si) was prepared, characterized and applied as a catalyst in Mizoroki–Heck cross-coupling reactions. The bis(oxazoline) (BOX) ligand has a hydroxyl group that can be anchored to 4-benzyl chloride-functionalized silica gel, followed by the coordination of palladium(II) chloride. The catalytic activity and the recyclability of Pd-BOX-Si have been investigated in the production of cinnamic acid derivatives via Mizoroki–Heck coupling reactions of acrylates with aryl halides; The Pd-BOX-Si catalyst demonstrated excellent catalytic activity. Characterization of the recycled Pd-BOX-Si catalyst revealed its good stability under the reaction conditions employed. 相似文献