complex catalyst
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Author(s):  
Yifei Chen ◽  
Yang Gao ◽  
Lingtao Wang ◽  
Hao Gong

Metal-organic framework which was composed of metal center and organic linkers possessing the similar structure with the homogeneous metal-complex catalyst for hydroformylation, thus it could be potentially used as the...


Author(s):  
V. A. Babkin ◽  
D. S. Andreev ◽  
A. V. Ignatov ◽  
E. S. Titova ◽  
V. T. Fomichev ◽  
...  

The ab initio 3.21G method was used to study the initiation mechanism of 2-methylpentene-1 under the action of a complex catalyst AlClCH - HO in heptane of stoichiometric composition 1:1:1:1. The energetics of this reaction is estimated, the values of its energy barrier and enthalpy are obtained.


2021 ◽  
Vol 2131 (2) ◽  
pp. 022015
Author(s):  
K F Koledina ◽  
I M Gubaydullin ◽  
S N Koledin

Abstract A mathematical model for the catalyst hydroalumination reaction of olefins with diisobutylaluminium hydride has been developed. In solving the direct kinetic problem applies multi-step method Gere variable order. When solving systems of ordinary differential equations in chemical kinetics, it is necessary to fulfill the balance relations at each sampling point. That ensures the fulfillment of the law of conservation of matter and the convergence of the numerical method. For the catalytic reaction of hydroalumination olefins in the presence of the organoaluminum compound diisobutylaluminum hydride, the problem of multicriteria optimization reaction conditions was solved based on a detailed kinetic model. The solutions found make it possible to optimally select the reaction conditions to achieve the maximum yield of target products, which can be based on the subsequent introduction of the laboratory reaction into production.


Molecules ◽  
2021 ◽  
Vol 26 (22) ◽  
pp. 6963
Author(s):  
María Maciá ◽  
Raúl Porcar ◽  
Vicente Martí-Centelles ◽  
Eduardo García-Verdugo ◽  
Maria Isabel Burguete ◽  
...  

Prolinamides are well-known organocatalysts for the HSiCl3 reduction of imines; however, custom design of catalysts is based on trial-and-error experiments. In this work, we have used a combination of computational calculations and experimental work, including kinetic analyses, to properly understand this process and to design optimized catalysts for the benchmark (E)-N-(1-phenylethylidene)aniline. The best results have been obtained with the amide derived from 4-methoxyaniline and the N-pivaloyl protected proline, for which the catalyzed process is almost 600 times faster than the uncatalyzed one. Mechanistic studies reveal that the formation of the component supramolecular complex catalyst-HSiCl3-substrate, involving hydrogen bonding breaking and costly conformational changes in the prolinamide, is an important step in the overall process.


Catalysts ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1148
Author(s):  
Dmytro S. Nesterov ◽  
Oksana V. Nesterova

Selective catalytic functionalization of organic substrates using peroxides as terminal oxidants remains a challenge in modern chemistry. The high complexity of interactions between metal catalysts and organic peroxide compounds complicates the targeted construction of efficient catalytic systems. Among the members of the peroxide family, m-chloroperoxybenzoic acid (m-CPBA) exhibits quite complex behavior, where numerous reactive species could be formed upon reaction with a metal complex catalyst. Although m-CPBA finds plenty of applications in fine organic synthesis and catalysis, the factors that discriminate its decomposition routes under catalytic conditions are still poorly understood. The present review covers the advances in catalytic C–H oxidation and olefine epoxidation with m-CPBA catalyzed by mono- and polynuclear complexes of nickel, a cheap and abundant first-row transition metal. The reaction mechanisms are critically discussed, with special attention to the O–O bond splitting route. Selectivity parameters using recognized model hydrocarbon substrates are summarized and important factors that could improve further catalytic studies are outlined.


2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Hiroki Koizumi ◽  
Katsuhiko Takeuchi ◽  
Kazuhiro Matsumoto ◽  
Norihisa Fukaya ◽  
Kazuhiko Sato ◽  
...  

AbstractTo reduce anthropogenic carbon dioxide (CO2) emissions, it is desirable to develop reactions that can efficiently convert low concentrations of CO2, present in exhaust gases and ambient air, into industrially important chemicals, without involving any expensive separation, concentration, compression, and purification processes. Here, we present an efficient method for synthesizing urea derivatives from alkyl ammonium carbamates. The carbamates can be easily obtained from low concentrations of CO2 as present in ambient air or simulated exhaust gas. Reaction of alkyl ammonium carbamates with 1,3-dimethyl-2-imidazolidinone solvent in the presence of a titanium complex catalyst inside a sealed vessel produces urea derivatives in high yields. This reaction is suitable for synthesizing ethylene urea, an industrially important chemical, as well as various cyclic and acyclic urea derivatives. Using this methodology, we also show the synthesis of urea derivatives directly from low concentration of CO2 sources in a one-pot manner.


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