2620-05-5Relevant articles and documents
Proton Chelating Ligands Drive Improved Chemical Separations for Rhodium
Narita, Hirokazu,Nicolson, Rebecca M.,Motokawa, Ryuhei,Ito, Fumiyuki,Morisaku, Kazuko,Goto, Midori,Tanaka, Mikiya,Heller, William T.,Shiwaku, Hideaki,Yaita, Tsuyoshi,Gordon, Ross J.,Love, Jason B.,Tasker, Peter A.,Schofield, Emma R.,Antonio, Mark R.,Morrison, Carole A.
, p. 8720 - 8734 (2019)
Current methods for the extraction of rhodium carry the highest carbon footprint and worst pollution metrics of all of the elements used in modern technological applications. Improving upon existing methods is made difficult by the limited understanding of the molecular-level chemistry occurring in extraction processes, particularly in the hydrometallurgical separation step. While many of the precious metals can be separated by solvent extraction, there currently exist no commercial extractants for Rh. This is due to its complicated mixed speciation upon leaching into hydrochloric acid, which gives rise to difficulties in designing effective reagents for solvent extraction. Herein we show that the diamidoamine reagent N-n-hexylbis(N-methyl-N-n-octylethylamide)amine transports Rh(III) from aqueous HCl into an organic phase as the monoaquated dianion [RhCl5(H2O)]2- through the formation of an outer-sphere assembly; this assembly has been characterized by experimentation (slope analysis, FT-IR and NMR spectroscopy, EXAFS, SANS, and ESI-MS) and computational modeling. The paper demonstrates the importance of applying a broad range of techniques to obtain a convincing mode of action for the complex processes involved in anion recognition in the solution phase. A consistent and comprehensive understanding of how the ligand operates to achieve Rh(III) selectivity over the competitor anion Cl- has emerged. This knowledge will guide the design of extractants and thus offers promise for improving the sustainability of metal extraction from both traditional mining sources and the recycling of secondary source materials.
Intramolecular carbene C-H insertion reactions of 2-diazo-2-sulfamoylacetamides
Que, Chuqiang,Huang, Peipei,Yang, Zhanhui,Chen, Ning,Xu, Jiaxi
, (2019)
The intramolecular C-H insertions of carbenes derived from 2-diazo-2-sulfamoylacetamides were studied. 2-Diazo-2-sulfamoylacetamides were first prepared from chloroacetyl chloride and secondary amines through acylation followed by sequential treatments with sodium sulfite, phosphorus oxychloride, secondary amines, and 4-nitrobenzenesulfonyl azide. The results indicate that: (1) 2-diazo-N,N-dimethyl-2-(N,N-diphenylsulfamoyl)acetamide can take the formal aromatic 1,5-C-H insertion in its N-phenylsulfonamide moiety to afford the corresponding 1,3-dihydrobenzo[c]isothiazole-3-carboxamide 2,2-dioxide derivative; (2) no aliphatic C-H insertions occur for 2-diazo-2-(N,N-dialkylsulfamoyl)acetamides; and (3) for 2-diazo-N-phenyl-2-(N-phenylsulfamoyl)acetamides, the formal aromatic 1,5-C-H insertion in the N-phenylacetamide moiety is favorable to afford the corresponding 3-sulfamoylindolin-2-one derivatives as sole or major products. The intramolecular competitive aromatic 1,5-C-H insertion reactions of 2-diazo-2-sulfamoylacetamides with aryl groups on both amide and sulfonamide groups reveal that the N-aryl substituents on acetamide are more active than those on sulfonamide. The chemoselectivity is controlled by electronic effect of the aryl group.
Synthesizing method for chloroacetamide compound
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Paragraph 0043-0045, (2019/10/01)
The invention discloses a synthesizing method for a chloroacetamide compound. In a reaction kettle, a secondary amine compound is dissolved in an organic solvent, the mixture is heated for reflux, chloroacetyl chloride is added into the mixture, a reflux reaction is conducted for 0.5-20 hours, and the chloroacetamide compound is obtained. According to the synthesizing method for the chloroacetamide compound, an acid binding agent is not used, discharging of wastewater in the after-treatment process is reduced, by keeping the reflux state of the system, hydrogen chloride gas generated from thereaction is exhausted out of the system and absorbed by water outside the system, high-purity hydrochloric acid is obtained, the waste is turned into wealth, the method comes up to the production standard of safety and environment protection, and discharging of waste gas, waste water and waste residues is reduced; according to the synthesizing method for the chloroacetamide compound, few operationsteps are utilized, the reaction speed is high, the product yield is high, the purity is high, the production cost is low, and the method is safe, friendly to the environment and suitable for industrial large-scale production.
Palladium-catalyzed olefination of aryl/alkyl halides with trimethylsilyldiazomethane via carbene migratory insertion
Mu, Qiu-Chao,Wang, Xing-Ben,Ye, Fei,Sun, Yu-Li,Bai, Xing-Feng,Chen, Jing,Xia, Chun-Gu,Xu, Li-Wen
supporting information, p. 12994 - 12997 (2018/11/23)
The direct olefination of aryl/alkyl halides with trimethylsilyldiazomethane (TMSD) as a C1- or C2-unit was achieved successfully via a metal carbene migratory insertion process, which offered a new access to afford (E)-vinyl silanes and (E)-silyl-substituted α,β-unsaturated amides in good yields and high chemoselectivity.
