Synthesis and formation mechanism of nanostructured NbAl3 intermetallic during mechanical alloying and a kinetic study on its formation

2012 ◽  
Vol 529 ◽  
pp. 36-44 ◽  
Author(s):  
H. Mostaan ◽  
F. Karimzadeh ◽  
M.H. Abbasi
Keyword(s):  
Mechanical Alloying ◽  
Kinetic Study ◽  
Formation Mechanism

Synthesis and kinetic study of (Mo,W)Si2–WSi2 nanocomposite by mechanical alloying

2012 ◽  
Vol 540 ◽  
pp. 248-259 ◽  
Author(s):  
Shahrouz Zamani ◽  
Hamid Reza Bakhsheshi-Rad ◽  
Mohammed Rafiq Abdul Kadir ◽  
Mohammad Reza Mohammad Shafiee
Keyword(s):  
Mechanical Alloying ◽  
Kinetic Study

Formation mechanism of NbSi2–Al2O3 nanocomposite subject to mechanical alloying

2014 ◽  
Vol 25 (4) ◽  
pp. 1357-1361 ◽  
Author(s):  
Z. Yazdani ◽  
F. Karimzadeh ◽  
M.H. Abbasi
Keyword(s):  
Mechanical Alloying ◽  
Formation Mechanism

scholarly journals Quantum Chemical and Kinetic Study on Radical/Molecule Formation Mechanism of Pre-Intermediates for PCTA/PT/DT/DFs from 2-Chlorothiophenol and 2-Chlorophenol Precursors

2019 ◽  
Author(s):  
Chenpeng Zuo ◽  
Hetong Wang ◽  
Wenxiao Pan ◽  
Siyuan Zheng ◽  
Fei Xu ◽  
...  
Keyword(s):  
Kinetic Study ◽  
Gas Phase ◽  
Formation Mechanism ◽  
Quantum Chemical ◽  
Polychlorinated Dibenzofurans ◽  
Phenoxy Radical ◽  
Phenyl Radical ◽  
Radical Species ◽  
Molecule Formation ◽  
Kinetic Calculations

Polychlorinated phenoxathiins (PCPTs), polychlorinated dibenzothiophenes (PCDTs), and polychlorinated thianthrenes (PCTAs) are sulfur analogues of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/DFs). Chlorothiophenols(CTPs) and chlorophenols (CPs) are key precursors to form PCTA/PT/DTs, which can form chloro(thio)phenoxy radical, sulfydryl/hydryl-substituted phenyl radical and (thio)phenoxyl diradicals. The available radical/radical PCTA/DT formation mechanism failed to explain the higher concentration of PCDTs than that of PCTAs under the pyrolysis or combustion conditions. Thus in this work, a detailed thermodynamics and kinetic calculations were carried out to investigate the pre-intermediates formation for PCTA/PT/DTs from radial/molecule coupling of 2-C(T)P with their key radical species. Our study found that the radial/molecule mechanism can thermodynamically and kinetically contribute to the gas-phase formation of PCTA/PT/DT/s. The S/C coupling modes to form thioether-(thio)enol intermediats are preferable over the O/C coupling modes to form ether-(thio)enol intermediats. Thus, although the radial/molecule coupling of chlorophenoxy radical with 2-C(T)P have no effect on the PCDD/PTs formation, the radial/molecule coupling of chlorothiophenoxy radical with 2-C(T)P play an important role in the PCDT/PT formation. Most importantly, the pre-PCDT intermediates formation pathways from the coupling of sulfydryl/hydryl-substituted phenyl radical with 2-C(T)P and the coupling of (thio)phenoxyl diradicals with 2-C(T)P are more favorable to pre-PCTA/PT intermediates formation pathways from the coupling of chlorothiophenoxy radical with 2-C(T)P, which can give reasonable explanation for the high PCDT-to-PCTA ratio in the environment.

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