以偏铝酸钠为催化剂实现由芳香甲腈到芳香甲酰胺的转化

在水和乙醇混合溶剂中,以偏铝酸钠做催化剂,使芳香甲腈水解成芳香甲酰胺。偏铝酸钠的催化性能稳定,选择性高。该方法反应条件温和、成本低廉、产率较高、绿色环保,且具有较好的应用前景。     

氢氧根钌配合物的合成及其对乙腈的催化水化研究

利用三乙胺对配合物[TpRu(PPh3)2(H2O)]BF4脱质子化合成了氢氧根钌配合物TpRu(PPh3)2(OH),并研究了TpRu(PPh3)2(OH)催化水化乙腈的反应.机理研究表明,催化循环的关键中间体为氧配位的酰亚胺配合物TpRu(PPh3)(CH3CN)(OCMe=NH),经过生成TpRu(PPh3)(κ2-N,O-NH=CMeN=CMeO)、水亲核进攻开环生成TpRu(PPh3)(NH=C(OH)Me)(OCMe=NH)、乙腈取代其NH=C(OH)Me配体产生乙酰胺、同时生成TpRu(PPh3)(CH3CN)(OCMe=NH)完成催化循环.     

An Efficient and Practical Protocol for Catalytic Hydrolysis of Nitriles by a Copper(I) Complex in Water

The cuprous complex – Cu₄I₄(H₂O)₄ – has been isolated and employed for the catalytic hydrolysis of arenecarbonitriles, cinnamonitrile, and arylacetonitriles to the corresponding amides in pure water in high yields of up to 98%. The catalyst can be easily recovered and reused without loss of catalytic activity at least five times. Oxindole could be prepared successfully by one‐pot domino protocols based on this method.     

催化反应与膜分离耦合系统中镍催化剂的使用

在用于对硝基苯酚加氢制备对氨基苯酚的反应-膜分离耦合系统中,催化剂在反应时以悬浮态形式应用,然后用无机陶瓷膜分离回收,催化加氢速率及膜过滤速率是决定该系统运行效率的关键.研究通过综合考察镍粉体催化剂的反应活性与膜分离性能来选择合适的催化剂.实验结果表明,在研究体系中,化学还原法制备的纳米镍粉活性优于物理气相沉积法制备的纳米镍粉和微米镍粉,主要因为化学还原法制备的纳米镍粉具有较大的活性比表面积.膜分离几种镍粉时,活性较高的纳米镍通量较低,而活性较低的微米镍通量较高.通过将具有高活性的纳米镍粉与具有高通量的微米镍粉以适当比例混合使用,不仅可以获得较高的催化活性,同时可以改善膜通量,对反应-膜分离耦合系统的工业化应用具有参考价值.     

Synthesis of Allylarenes via Catalytic Decarboxylation of Allyl Benzoates

A catalyst system consisting of the palladium(0) complex Pd₂(dba)₃ and tri(p‐tolyl)phosphine was found to efficiently promote the decarboxylation of allyl benzoates with formation of allylarenes. This catalytic C O activation followed by extrusion of carbon dioxide and C C bond formation represents a sustainable alternative to traditional waste‐intensive cross‐couplings. The scope of the transformation includes allyl and cinnamyl esters of various ortho‐substituted benzoic acids. For particularly activated substrates, the palladium catalyst can optionally be replaced by an inexpensive nickel complex.

     

Gallium (III) Triflate Catalyzed Beckmann Rearrangement

Gallium triflate catalyzed Beckmann rearrangement is described. Various aliphatic or aromatic amides are obtained from the corresponding ketoximes in good yields. Gallium triflate exhibits high catalytic activity for a wide variety of substrates.     

Highly Active and Selective Platinum(0)‐Carbene Complexes. Efficient,Catalytic Hydrosilylation of Functionalised Olefins

Readily available N‐heterocyclic platinum‐carbene complexes 1 are highly efficient catalysts for the regioselective hydrosilylation of alkenes. These novel organometallics tolerate a wide range of functional and protecting groups, can be stored for prolonged periods of time and are particularly active (TON>10⁶).     

Acid‐Free Nickel Catalyst for Stereo‐ and Regioselective Hydrophosphorylation of Alkynes: Synthetic Procedure and Combined Experimental and Theoretical Mechanistic Study

The nickel catalyst prepared in situ from nickel bis(acetylacetonate) [Ni(acac)₂] precursor and bis(diphenylphosphino)ethane (DPPE) ligand has shown excellent performance in the hydrophosphorylation of alkynes. Markovnikov‐type regioselective addition to terminal alkynes and stereoselective addition to internal alkynes were carried out with high selectivity without an acidic co‐catalyst (in contrast to the palladium/acid catalytic system). Various H‐phosphonates and alkynes reacted smoothly in the developed catalytic system with up to 99% yield. The mechanisms of catalyst activation and C P bond formation were revealed by experimental (NMR, ESI‐MS, X‐ray) and theoretical (density functional calculations) studies. Two different pathways of the alkyne insertion in the coordination sphere of the metal are reported for the first time.     

过渡金属氧化物催化腈水合生成酰胺的研究进展

腈水合生成酰胺具有原子经济性高以及无其他副产物生成的优点。通常腈水合生成酰胺是在强酸或强碱催化下进行的,但其具有腈过度水解生成羧酸以及需要中和催化剂生成盐等缺点。采用过渡金属氧化物如氧化锰(MnO₂)、氧化镍(NiO)、氧化铈(CeO₂)以及氢氧化钌[Ru(OH)_x]为催化剂替代强酸或强碱可克服上述缺点。本文总结了上述过渡金属氧化物为催化剂催化腈水合生成酰胺反应的进展,从中可以看到腈水合生成酰胺反应依赖于催化剂的种类、制备方法以及腈的结构。对每种催化剂的制备方法、使用范围、优缺点进行了分析。对各种催化剂催化腈水合生成酰胺反应的可能机理进行讨论。根据以上讨论,预期此类催化剂将向复合型和负载型方向发展。     

均相催化水合法合成乙二醇动力学研究

在反应温度为45～75℃,NY 健化剂浓度为0.093mol/L,水比为6～10的反应条件下,对均相催化水合法合成乙二醇动力学进行了研究。测定了反应速率常数及反应过程中溶液 pH 值的变化。依据实验结果,提出了反应机理,建立了反应动力学方程,并利用 Levenberg-Marquardt 方法回归了动力学参数。研究结果表明:在 NY 催化剂存在下,均相催化水合法合成乙二醇反应对环氧乙烷浓度是一级反应,其表观活化能为71113.8 J/mol 和指前因子3.05×10~9 min~(-1)。相对直接水合法而言,NY 催化剂降低了反应的活化能,大大提高了反应速度。     

Recent Advances in Transition Metal‐Catalyzed Hydrogenation of Nitriles

Amines are important building blocks possessing various applications in agrochemicals, the fine chemical industry, pharmaceuticals, materials science and biotechnology. The catalytic hydrogenation of nitriles is an important reaction for the one‐step synthesis of diverse amines. However, significant amounts of side product formation during the course of the reaction is a major issue. In recent years, an enormous amount of work has been reported using both homogeneous and heterogeneous transition metal complex catalysts for the selective reduction of nitriles. Transition metal catalysts are the most crucial factor that controls the selectivity in this reaction. Therefore, transition metal catalysts are the central point of this review. We have also briefly discussed the effect of reaction parameters, selectivity to different substrate structures and reaction mechanisms. This review provides an overview of recent developments in transition metal‐catalyzed nitrile reduction along with examples which highlight its vast potential in organic transformations.

     

腈水合酶固定化方法和催化特性的研究

以一种能够产生腈水合酶诺卡氏菌为研究对象,针对原来的海藻酸盐包埋法存在的固定化细胞强度较小、通透性较差等问题,改进了对酶的固定化方法,并对固定化腈水合酶的催化特性:最适反应温度、pH值、底物丙烯腈浓度、和表面活性剂性质和丙烯酰胺累积浓度对酶活性的影响等五个方面进行了研究。其中固定化腈水合酶最适反应温度在15~25°C;pH 7.0左右;底物丙烯腈浓度为3%~4%;Triton X-100对酶活性基本无影响,而Tween 80和Tween 60对酶活力有抑制作用;固定化腈水合酶在丙烯酰胺累积浓度为15%~20%之间时,酶活性较好。     

催化氢甲酰化反应的研究进展

回顾烯烃氢甲酰化60年来取得的成就,简要地概述了氢甲酰化反应催化体系的发展过程。通过对各个阶段的催化剂性能比较,分析了水溶性铑膦复合物催化剂成为低碳烯烃氢甲酰化首选催化剂的主要原因。阐述了现阶段甲酰化催化体系的研究进展和发展趋势。指出新的水－有机两相催化多相催化技术将是今后的努力方向。     

Highly Stereoselective Semihydrogenation of Alkynes Promoted by Nickel(0) Nanoparticles

A new method for the highly stereoselective cis‐semihydrogenation of internal alkynes is described based on in situ generated Ni(0) nanoparticles and molecular hydrogen. This reduction system also allows the semihydrogenation of terminal alkynes.     

环氧乙烷非均相催化水合动力学及均温反应器热稳定性分析

采用碳纳米管增强复合材料催化剂,在等温积分反应器中获得环氧乙烷非均相催化水合宏观反应动力学实验数据,建立了幂函数型宏观反应动力学方程,采用Levenberg-Marquardt法对动力学模型参数进行估算,并以该动力学模型为基础,分析了均温反应器的热稳定性。结果表明,生成乙二醇主反应的表观活化能为71.7 k J/mol,与两个典型的串联副反应的活化能接近。模型参数统计检验结果表明,该宏观动力学方程参数是适定的,可用于工业反应器的设计。给出的反应器关键参数的计算方法,可为乙二醇合成反应器的模拟计算和设计开发提供必要的依据。     

环氧乙烷催化水合制乙二醇工艺放大研究

以环氧乙烷催化水合制乙二醇小试研究所开发出的一系列环氧乙烷均相催化剂和相应的工艺流程为基础,进行放大试验,考察催化剂的放大性能,进一步完善工艺技术。通过放大试验进一步验证了小试试验结果的正确性,并对生产工艺的最优化条件进行了筛选和确定,为下一步进行工业化生产奠定了坚实的基础。     

硫酸镍催化合成紫罗兰酮

用硫酸镍催化假性紫罗兰酮的环化反应，得到了较高产率的紫罗兰酮。探索了催化剂用量、反应温度、反应时间、溶剂用量和溶剂的种类等因素对该环化反应的影响。最佳合成条件如下：5．6mL（79．6％）假性紫罗兰酮，催化剂用量为假性紫罗兰酮的3％（摩尔百分率），甲苯（溶剂）用量为8mL，环化反应温度为40～50℃，反应时间为2．5h，在此合成条件下所得紫罗兰酮的产率为67．4％。选择极性较大的物质（如三氯甲烷）作溶剂有利于该环化反应的进行。