Rhodium Single-Atom Catalyst Design through Oxide Support Modulation for Selective Gas-Phase Ethylene Hydroformylation

A frontier challenge in single-atom (SA) catalysis is the design of fully inorganic sites capable of emulating the high reaction selectivity traditionally exclusive of organometallic counterparts in homogeneous catalysis. Modulating the direct coordination environment in SA sites, via the exploitation of the oxide support's surface chemistry, stands as a powerful albeit underexplored strategy. We report that isolated Rh atoms stabilized on oxygen-defective SnO₂ uniquely unite excellent TOF with essentially full selectivity in the gas-phase hydroformylation of ethylene, inhibiting the thermodynamically favored olefin hydrogenation. Density Functional Theory calculations and surface characterization suggest that substantial depletion of the catalyst surface in lattice oxygen, energetically facile on SnO₂, is key to unlock a high coordination pliability at the mononuclear Rh centers, leading to an exceptional performance which is on par with that of molecular catalysts in liquid media.     

A Novel Environmentally Benign Method for the Selective Oxidation of Alcohols to Aldehydes and Ketones

In the presence of [Ru(terpyridine)(2,6‐pyridinedicarboxylate)], aliphatic and benzylic alcohols are oxidized to the corresponding aldehydes or ketones with high selectivity by using hydrogen peroxide as the oxidant. There is no need for the addition of co‐catalysts or organic solvents. By applying an optimized reaction protocol, high catalyst productivity (turnover number>10 000) and activity (turnover frequency up to 14 800 h^?1) has been achieved.     

Merging N-Hydroxyphthalimide into Metal-Organic Frameworks for Highly Efficient and Environmentally Benign Aerobic Oxidation

Two highly efficient metal-organic framework catalysts TJU-68-NHPI and TJU-68-NDHPI have been successfully synthesized through solvothermal reactions of which the frameworks are merged with N-hydroxyphthalimide (NHPI) units, resulting in the decoration of pore surfaces with highly active nitroxyl catalytic sites. When t-butyl nitrite (TBN) is used as co-catalyst, the as-synthesized MOFs are demonstrated to be highly efficient and recyclable catalysts for a novel three-phase heterogeneous oxidation of activated C−H bond of primary and secondary alcohols, and benzyl compounds under mild conditions. Based on the high efficiency and selectivity, an environmentally benign system with good sustainability, mild conditions, simple work-up procedure has been established for practical oxidation of a wide range of substrates.     

钴基催化剂催化环己烯氢甲酰化研究

以氯化钴和锰铁合金粉为钴基催化体系的前驱体,研究了该催化剂体系对环己烯氢甲酰化反应制备环己烷基甲醛的催化性能;并考察了溶剂、温度、压力等反应条件的影响.实验结果表明,选用四氢呋喃作为溶剂,反应的活性较高,选择性较好.在反应温度为145℃,合成气压力为8.0MPa,钴与烯烃的物质的量的比为0.01,反应时间为0.5h条件下,能得到环己烯的转化率为89%,环己烷基甲醛的选择性达到96%的结果.     

An Improved Ruthenium Catalyst for the Environmentally Benign Amination of Primary and Secondary Alcohols

The N‐alkylation of amines in the presence of different ruthenium catalysts generated in situ was investigated. Among the various catalysts tested, the combination of [Ru₃(CO)₁₂] and N‐phenyl‐2‐(dicyclohexylphosphanyl)pyrrole showed the best performance. By applying this novel catalyst, a variety of functionalized alcohols and amines were converted into the corresponding secondary amines in high yield.     

Environmentally Benign,Rapid, and Selective Extraction of Gold from Ores and Waste Electronic Materials

The extraction of gold from ores and electronic waste is an important topic worldwide, as this precious metal has immense value in a variety of fields. However, serious environmental pollution and high energy consumption due to the use of toxic oxidation reagents and harsh reaction conditions is a well‐known problem in the gold industry. Herein, we report a new chemical method based on the combined use of N ‐bromosuccinimide (NBS) and pyridine (Py), which has a greatly decreased environmental impact and reagent cost, as well as mild reaction requirements. This method can directly leach Au⁰ from gold ore and electronic waste to form Au^III in water. The process is achieved in a yield of approximately 90 % at room temperature and a nearly neutral pH. The minimum dose of NBS/Py is as low as 10 mm , which exhibits low toxicity towards mammalian cells and animals as well as aquatic creatures. The high leaching selectivity of Au over other metals during gold leaching is demonstrated, showing that this method has great potential for practical industrial application towards the sustainable refining of gold from ores and electronic waste.     

Environmentally Benign,Rapid, and Selective Extraction of Gold from Ores and Waste Electronic Materials

The extraction of gold from ores and electronic waste is an important topic worldwide, as this precious metal has immense value in a variety of fields. However, serious environmental pollution and high energy consumption due to the use of toxic oxidation reagents and harsh reaction conditions is a well‐known problem in the gold industry. Herein, we report a new chemical method based on the combined use of N ‐bromosuccinimide (NBS) and pyridine (Py), which has a greatly decreased environmental impact and reagent cost, as well as mild reaction requirements. This method can directly leach Au⁰ from gold ore and electronic waste to form Au^III in water. The process is achieved in a yield of approximately 90 % at room temperature and a nearly neutral pH. The minimum dose of NBS/Py is as low as 10 mm , which exhibits low toxicity towards mammalian cells and animals as well as aquatic creatures. The high leaching selectivity of Au over other metals during gold leaching is demonstrated, showing that this method has great potential for practical industrial application towards the sustainable refining of gold from ores and electronic waste.     

A Cooperative Strategy for the Highly Selective Intermolecular Oxycarbonylation Reaction of Alkenes using a Palladium Catalyst

A novel method for intermolecular functionalization of terminal and internal alkenes has been designed. The electrophilic reagent, hypervalent iodine, plays a key role in this process by activating the alkene C=C bond for nucleophilic addition of the palladium catalyst. This process generates an iodonium‐containing palladium species which undergoes CO insertion. The new approach, intermolecular oxycarbonylaton reactions of alkenes, has been achieved and carried out under mild reaction conditions to produce the corresponding β‐oxycarbonylic acids with excellent efficiencies and levels of regio‐ and diastereoselectivity.     

An Environmentally Benign Water Promoted Catalyst Free Highly Efficient,One‐pot Synthesis of 2‐Imino‐4‐thiazolidinone

A practical and efficient protocol has been developed for the synthesis of 2‐imino‐4‐thiazolidinone through a unique one pot three‐component reaction of variety of amines, isothiocyanate and ethylbromoacetate in water. The method is free of catalyst and other toxic solvents, has shorter reaction times, high‐yielding, effortlessness in isolation of product, making it more eco‐friendly process, and suitable for large scale operation.     

一种环境友好的制备硝基芳胺的方法

Themono reductionofaromaticdinitro com poundstothecorrespondingnitroanilinesisofindus triallyimmenseimportanceastheyarewidelyusedintermediatesfordyes,pharmaceuticalsandagro chemicals .Mostoften ,hydrogensulfideoritsvaria tions ,ironorstannouschlorideisusedinthereactionsystem ,butitresultsinalotofwaste .Recently ,somehomogeneousandheterogeneouscatalystsys temsincombinationwithdifferenthydrogendonorshavebeenusedfortheselectivereductionofaromaticdinitro compounds ,andCO/H2 Oasahydrogensourcefort…     

Highly Efficient,Selective, and Stable CO2 Electroreduction on a Hexagonal Zn Catalyst

Electrocatalytic CO₂ conversion into fuel is a prospective strategy for the sustainable energy production. However, still many parts of the catalyst such as low catalytic activity, selectivity, and stability are challenging. Herein, a hierarchical hexagonal Zn catalyst showed highly efficient and, more importantly, stable performance as an electrocatalyst for selectively producing CO. Moreover, we found that its high selectivity for CO is attributed to morphology. In electrochemical analysis, Zn (101) facet is favorable to CO formation whereas Zn (002) facet favors the H₂ evolution during CO₂ electrolysis. Indeed, DFT calculations showed that (101) facet lowers a reduction potential for CO₂ to CO by more effectively stabilizing a ^.COOH intermediate than (002) facet. This further suggests that tuning the crystal structure to control (101)/(002) facet ratio of Zn can be considered as a key design principle to achieve a desirable product from Zn catalyst.     

Highly Efficient,Selective, and Stable CO2 Electroreduction on a Hexagonal Zn Catalyst

Electrocatalytic CO₂ conversion into fuel is a prospective strategy for the sustainable energy production. However, still many parts of the catalyst such as low catalytic activity, selectivity, and stability are challenging. Herein, a hierarchical hexagonal Zn catalyst showed highly efficient and, more importantly, stable performance as an electrocatalyst for selectively producing CO. Moreover, we found that its high selectivity for CO is attributed to morphology. In electrochemical analysis, Zn (101) facet is favorable to CO formation whereas Zn (002) facet favors the H₂ evolution during CO₂ electrolysis. Indeed, DFT calculations showed that (101) facet lowers a reduction potential for CO₂ to CO by more effectively stabilizing a ^.COOH intermediate than (002) facet. This further suggests that tuning the crystal structure to control (101)/(002) facet ratio of Zn can be considered as a key design principle to achieve a desirable product from Zn catalyst.     

Domino Hydroformylation/Aldol Condensation/Hydrogenation Catalysis: Highly Selective Synthesis of Ketones from Olefins

A general and highly chemo‐ and regioselective synthesis of ketones from olefins by domino hydroformylation/aldol condensation/hydrogenation reaction has been developed. A variety of olefins are efficiently converted into various ketones in good to excellent yields and regioselectivities in the presence of a specific rhodium phosphine/base–acid catalyst system.     

A Stable Nanocobalt Catalyst with Highly Dispersed CoNx Active Sites for the Selective Dehydrogenation of Formic Acid

Novel nanostructured catalysts with highly dispersed cobalt have been synthesized by the pyrolysis of metal phenanthroline complexes. Materials with significantly different properties were obtained by simply tuning the metal/ligand ratio. The catalytic potential of this class of compounds is shown by the first example of the dehydrogenation of formic acid under the catalysis of atomically dispersed cobalt. From TEM, XPS, and XRD characterization, KSCN poisoning, and acid leaching, the formation of CoN_x species as the active site seems key to the success of this reaction. Excellent stability and recyclability make this new catalyst also attractive for other applications.