In-situ facile synthesis novel N-doped thin graphene layer encapsulated Pd@N/C catalyst for semi-hydrogenation of alkynes
作者:Jianguo Liu、Shanshan Lin、Jiangming Sun、Longlong Ma
DOI:10.1016/j.jcat.2021.11.012
日期:2022.1
Transition metal-catalyzed semi-hydrogenation of alkynes has become one of the most popular methods for alkene synthesis. Specifically, the noble metal Pd, Rh, and Ru-based heterogeneous catalysts have been widely studied and utilized in both academia and industry. But the supported noble metal catalysts are generally suffering from leaching or aggregation during harsh reaction conditions, which resulting
过渡金属催化的炔烃半加氢已成为最流行的烯烃合成方法之一。具体而言,贵金属 Pd、Rh 和 Ru 基多相催化剂已在学术界和工业界得到广泛研究和应用。但负载型贵金属催化剂在苛刻的反应条件下通常会发生浸出或聚集,导致催化反应活性和稳定性较低。在此,我们报道了氮掺杂石墨烯包封 Pd 催化剂的简便合成及其在炔烃化学选择性半氢化中的应用。通过 X 射线和 TEM 分析证实,石墨烯层对活性 Pd 纳米金属物种起到了“防弹”作用,增强了反应条件下的催化稳定性。优化的准备Pd@N/C催化剂在苯乙炔和其他类型炔烃的半氢化中表现出优异的效率,这些炔具有未官能化或官能化的取代基,包括氢化敏感官能团(NO 2、酯和卤素)。
Monodisperse nickel-nanoparticles for stereo- and chemoselective hydrogenation of alkynes to alkenes
作者:Kathiravan Murugesan、Ahmad S. Alshammari、Manzar Sohail、Matthias Beller、Rajenahally V. Jagadeesh
DOI:10.1016/j.jcat.2018.12.018
日期:2019.2
Here, we report the use of monosaccharides for the preparation of novel nickel nanoparticles (NP), which constitute selective hydrogenation catalysts. For example, immobilization of fructose and Ni(OAc)2 on silica and subsequent pyrolysis under inert atmosphere produced graphitic shells encapsulated Ni-NP with uniform size and distribution. Interestingly, fructose acts as structure controlling compound
Nickel‐Catalyzed Stereodivergent Synthesis of
<i>E</i>
‐ and
<i>Z</i>
‐Alkenes by Hydrogenation of Alkynes
作者:Kathiravan Murugesan、Charles Beromeo Bheeter、Pim R. Linnebank、Anke Spannenberg、Joost N. H. Reek、Rajenahally V. Jagadeesh、Matthias Beller
DOI:10.1002/cssc.201900784
日期:2019.7.19
alkynes to E‐ and Z‐alkenes by using nickelcatalysts was developed. Simple Ni(NO3)2⋅6 H2O as a catalyst precursor formed active nanoparticles, which were effective for the semihydrogenation of several alkynes with high selectivity for the Z‐alkene (Z/E>99:1). Upon addition of specific multidentate ligands (triphos, tetraphos), the resulting molecular catalysts were highly selective for the E‐alkene products
开发了一种使用镍催化剂将炔烃立体发散氢化为E-和Z-烯烃的便捷方案。简单的Ni(NO 3 ) 2 ⋅6 H 2 O作为催化剂前体形成活性纳米粒子,可有效地对多种炔烃进行半加氢,并且对Z-烯烃具有高选择性( Z / E > 99:1)。添加特定的多齿配体(三磷、四磷)后,所得分子催化剂对E-烯烃产物具有高度选择性(E/Z > 99:1)。机理研究表明Z-烯烃选择性催化剂是非均相的,而E-烯烃选择性催化剂是均相的。在后一种情况下,炔烃首先被氢化为Z-烯烃,随后异构化为E-烯烃。该提议得到了密度泛函理论计算的支持。这种合成方法被证明普遍适用于超过 40 个例子,并且可扩展到多克规模的实验。
Selective Transfer Semihydrogenation of Alkynes with H
<sub>2</sub>
O (D
<sub>2</sub>
O) as the H (D) Source over a Pd‐P Cathode
internal alkynes using H2O (D2O) as the H (D) source over a Pd‐P alloy cathode at a lower potential. P‐doping caused the enhanced specific adsorption of alkynes and the promoted intrinsic activity for producing adsorbed atomic hydrogen (H*ads) from water electrolysis. The semihydrogenation of alkynes could be accomplished at a lower potential with up to 99 % selectivity and 78 % Faraday efficiency of alkene
Lewis base-assisted Lewis acid-catalyzed selective alkene formation via alcohol dehydration and synthesis of 2-cinnamyl-1,3-dicarbonyl compounds from 2-aryl-3,4-dihydropyrans
作者:Changhui Liu、Bin Pan、Yanlong Gu
DOI:10.1016/s1872-2067(15)61084-1
日期:2016.6
Abstract Acid-catalyzed dehydration of alcohols has been widely employed for the synthesis of alkenes. However, activated alcohols when employed as substrates in dehydration reactions are often plagued by the lack of alkene selectivity. In this work, the reaction system can be significantly improved through enhancing the performance of Lewis acid catalysts in the dehydration of activated alcohols by