The use of radioisotopes in studies of reaction mechanism. Part II. Theoretical calculation and experimental measurement of halogen exchange of 1-halogeno-2,4-dinitrobenzenes in methanol and NN-dimethylformamide

Author(s):  
F. H. Kendall ◽  
J. Miller ◽  
R. Wong
2020 ◽  
Vol 26 (6) ◽  
Author(s):  
Huifeng Zhao ◽  
Peng Li ◽  
Meigang Duan ◽  
Feng Xie ◽  
Jie Ma

2005 ◽  
Vol 83 (9) ◽  
pp. 1597-1605 ◽  
Author(s):  
Hiroto Tachikawa

Direct ab initio molecular dynamics (MD) calculations have been carried out for the reaction of cyclopropenyl chloride with halide ion (F–) (F– + (CH)3Cl → F(CH)3 + Cl–) in gas phase. Both SN2 and SN2′ channels were found as product channels. These channels are strongly dependent on the collision angle of F– to the target (CH)3Cl molecule. The collision at one of the carbon atoms of the C=C double bond leads to the SN2′ reaction channel; whereas the collision at the methylene carbon atom leads to the SN2 reaction channel. The reactions proceed via a direct mechanism without long-lived complexes. The reaction mechanism is discussed on the basis of the theoretical results.Key words: SN2 reaction, direct ab initio molecular dynamics, halogen exchange, reaction mechanism.


2021 ◽  
Author(s):  
Hui Li ◽  
Wanyong Tang ◽  
Zifan Ma

This paper focuses on uncovering the regioselectivity, directing group, ligand, solvation effect in B-H activation that investigated by DFT calculations. The reaction mechanism was investigated in vacuum, and the advantage...


Metals ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 942 ◽  
Author(s):  
Miaotian Zhang ◽  
Shuangfu Suo ◽  
Yang Jiang ◽  
Guoying Meng

As a basic mechanical component, the sealing ring is widely used in industrial, aerospatial, and other fields. In this study, an elastic metal C-shaped sealing ring with a wave structure was taken as an example, and its performance was analyzed theoretically and measured experimentally. First, an experimental study was performed on the C-ring seal. The proposed method for experimental measurement of the contact stress of the C-ring seal involved innovative use of a universal electronic testing machine and pressure sensitive paper, in conjunction with the hue–saturation–brightness (HSB) method. Based on the discoloration of the pressure sensitive paper after contact stress, computer software was used for analysis, the discoloration was digitized, and the contact stress was established. Second, a theoretical calculation model of the C-ring seal was established using ANSYS software, and a finite element theoretical calculation of the mechanical properties of the sealing ring was established. Finally, the contact stress results were compared with the model calculation results of the C-ring seal. The error between the two was small (4.8%), which proved the validity of the calculation model and the scientificity of the experimental method.


2016 ◽  
Vol 822 ◽  
pp. 285-290
Author(s):  
Gheorghe Popa ◽  
Augustin Constantinescu ◽  
Stefanita Ciunel

This paper shows how to calculate the speed of travel for a tractor equipped with an additional transmission (hydrostatic transmission). Determination is theoretically and experimentally, comparing the results. Theoretical calculation is done using MathCAD program. An experimental measurement is determined by the device called “fifth wheel", equipped with speed measuring transducer.


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