Ligand-free Guerbet-Type Reactions in Air Catalyzed by In-Situ Formed Complexes of Base Metal Salt Cobaltous Chloride

Author(s):  
Pran Gobinda Nandi ◽  
Pradhuman Kumar ◽  
Akshai Kumar

Inexpensive, earth-abundant and environmentally benign cobaltous chloride efficiently accomplishes the catalytic β-alkylation of alcohols in air at 140 °C. At higher loadings of cobaltous chloride (1 mol%) in the presence...

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Chuhan Li ◽  
Shuo Song ◽  
Yuling Li ◽  
Chang Xu ◽  
Qiquan Luo ◽  
...  

AbstractHomogeneous earth-abundant metal catalysis based on well-defined molecular complexes has achieved great advance in synthetic methodologies. However, sophisticated ligand, hazardous activator and multistep synthesis starting from base metal salts are generally required for the generation of active molecular catalysts, which may hinder their broad application in large scale organic synthesis. Therefore, the development of metal cluster catalysts formed in situ from simple earth-abundant metal salts is of importance for the practical utilization of base metal resource, yet it is still in its infancy. Herein, a mixture of catalytic amounts of cobalt (II) iodide and potassium tert-butoxide is discovered to be highly active for selective hydroboration of vinylarenes and dihydroboration of nitriles, affording a good yield of diversified hydroboration products that without isolation can readily undergo further one pot transformations. It should be highlighted that the alkoxide-pinacolborane combination acts as an efficient activation strategy to activate cobalt (II) iodide for the generation of metastable heterotopic cobalt catalysts in situ, which is proposed to be catalytically active species.


2020 ◽  
Vol 56 (12) ◽  
pp. 1819-1822 ◽  
Author(s):  
Hui Wang ◽  
Ge Zhang ◽  
Qian Zhang ◽  
Ying Wang ◽  
Yanfei Li ◽  
...  

The non-directed hydrosilylation of cyclopropenes with earth-abundant and environmentally benign base metal catalysis was described.


Synthesis ◽  
2019 ◽  
Vol 51 (06) ◽  
pp. 1293-1310 ◽  
Author(s):  
Qiang Liu ◽  
Xufang Liu ◽  
Bin Li

The catalytic olefin isomerization reaction is a highly efficient and atom-economic transformation in organic synthesis that has attracted tremendous attention both in academia and industry. Recently, the development of Earth-abundant metal catalysts has received growing interest owing to their wide availability, sustainability, and ­environmentally benign nature, as well as the unique properties of non-precious metals. This review provides an overview of a broad range of base-metal-catalyzed olefin isomerization reactions categorized ­according to their different reaction mechanisms.1 Introduction2 Base-Metal-Catalyzed Olefin Isomerization Reactions3 Base-Metal-Catalyzed Cycloisomerization Reactions4 Conclusion


2020 ◽  
Vol 92 (10) ◽  
pp. 1717-1731
Author(s):  
Yucui Hou ◽  
Zhi Feng ◽  
Jaime Ruben Sossa Cuellar ◽  
Weize Wu

AbstractPhenolic compounds are important basic materials for the organic chemical industry, such as pesticides, medicines and preservatives. Phenolic compounds can be obtained from biomass, coal and petroleum via pyrolysis and liquefaction, but they are mixtures in oil. The traditional methods to separate phenols from oil using alkaline washing are not environmentally benign. To solve the problems, deep eutectic solvents (DESs) and ionic liquids (ILs) have been developed to separate phenols from oil, which shows high efficiency and environmental friendliness. In this article, we summarized the properties of DESs and ILs and the applications of DESs and ILs in the separation of phenols and oil. There are two ways in which DESs and ILs are used in these applications: (1) DESs formed in situ using different hydrogen bonding acceptors including quaternary ammonium salts, zwitterions, imidazoles and amides; (2) DESs and ILs used as extractants. The effect of water on the separation, mass transfer dynamics in the separation process, removal of neutral oil entrained in DESs, phase diagrams of phenol + oil + extractant during extraction, are also discussed. In the last, we analyze general trends for the separation and evaluate the problematic or challenging aspects in the separation of phenols from oil mixtures.


2017 ◽  
Vol 23 (50) ◽  
pp. 12275-12282 ◽  
Author(s):  
Jonas Häusler ◽  
Saskia Schimmel ◽  
Peter Wellmann ◽  
Wolfgang Schnick

2015 ◽  
Vol 44 (19) ◽  
pp. 8906-8916 ◽  
Author(s):  
Sankar Das ◽  
Subhra Jana

Halloysite/metal nanocomposites have been synthesized through the immobilization of preformed and in situ synthesized metal nanoparticles over halloysite surfaces, which in turn produce efficient, cost-effective, and environmentally benign heterogeneous catalysts.


2020 ◽  
Author(s):  
Fatma Pelin Kinik ◽  
Tu Ngugen ◽  
Mounir Mensi ◽  
Christopher Ireland ◽  
Kyriakos Stylianou ◽  
...  

<div> <div> <div> <p>Metal nanoparticles (NPs) are usually stabilized by a capping agent, a surfactant, or a support material, to maintain their integrity. However, these strategies can impact their intrinsic catalytic activity. Here, we demonstrate that the in-situ formation of copper NPs (Cu0NPs) upon the reduction of the earth-abundant Jacquesdietrichite mineral with ammonia borane (NH3BH3, AB) can provide an alternative solution for stability issues. During the formation of Cu0NPs, hydrogen gas is released from AB, and utilized for the reduction of nitroarenes to their corresponding anilines, at room temperature and under ambient pressure. After the nitroarene-to-aniline conversion is completed, regeneration of the mineral occurs upon the exposure of Cu0NPs to air. Thus, the hydrogenation reaction can be performed multiple times without the loss of the Cu0NPs’ activity. As a proof-of-concept, the hydrogenation of drug molecules “flutamide” and “nimesulide” was also performed and isolated their corresponding amino-compounds in high selectivity and yield. </p> </div> </div> </div>


2021 ◽  
Author(s):  
Rafał Kusy ◽  
Karol Grela

Herein, we present (<i>Z</i>)-selective transfer semihydrogenation of alkynes based on in situ generated CuNPs in the presence of hydrogen donors, such as ammonia-borane and a protic solvent. This environmentally-friendly method is characterized by operational simplicity combined with high stereo- and chemoselectivity and functional group compatibility. Auto-oxidation of CuNPs after the semihydrogenation reaction is completed results in the formation of water-soluble ammonia complex, so that the catalyst may be reused several times by simple phase-separation with no need of any special regeneration process. Formed NH<sub>4</sub>B(OR)<sub>4</sub> can be easily transformed back to ammonia-borane or to boric acid. In addition, one-pot tandem sequence involving Suzuki reaction followed by semihydrogenation was presented.<br>


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