scholarly journals Novel Conjugated Polymer Containing Aromatic Ring and Selenium in Backbone. Kinetics of Substituent Effect on the Addition Reaction of Benzeneselenols to Ethynylbenzenes as a Model for Addition Polymerization

1995 ◽  
Vol 27 (7) ◽  
pp. 683-692 ◽  
Author(s):  
Nobuki Metaka ◽  
Eiichi Kobayashi ◽  
Sadahito Aoshima ◽  
Junji Furukawa
Keyword(s):  
Aromatic Ring ◽  
Conjugated Polymer ◽  
Substituent Effect ◽  
Addition Reaction ◽  
Addition Polymerization ◽  
Kinetics Of

scholarly journals Synthesis and characterization of a new conjugated polymer containing bithiazole group and its thermal decomposition kinetics

2020 ◽  
Vol 39 (2) ◽  
pp. 227
Author(s):  
Adnan Kurt ◽  
Hacer Andan ◽  
Murat Koca
Keyword(s):  
Thermal Decomposition ◽  
Heating Rate ◽  
Conjugated Polymer ◽  
Three Dimensional ◽  
Heating Rates ◽  
Diffusion Type ◽  
Optimum Heating ◽  
Rate Loss ◽  
Kinetics Of

A new conjugated polymer containing a bithiazole group is prepared by the polycondensation of 2,2'-diamino-4,4'-bithiazole and terephthaldialdehyde in the presence of glacial acetic acid. The kinetics of thermal degradation of the new polymer are investigated by thermogravimetric analysis at different heating rates. The temperature corresponding to the maximum rate loss shifts to higher temperatures with increasing heating rate. The thermal decomposition activation energies of the conjugated polymer in a conversion range of 3–15 % are 288.4 and 281.1 kJ/mol by the Flynn–Wall–Ozawa and Kissinger methods, respectively. The Horowitz–Metzger method shows that the thermodegradation mechanism of the conjugated polymer proceeds over a three-dimensional diffusion type deceleration D3 mechanism. The optimum heating rate is 20 ºC/min.

Thermal Addition Reaction of Aroylketene with Ethyl Vinyl Ether: Aromatic Substituent Effect on Aroylketene Reactivity

Heterocycles ◽  
1996 ◽  
Vol 43 (11) ◽  
pp. 2457 ◽  
Author(s):  
Takehiro Sano ◽  
Jun Toda ◽  
Toshiaki Saitoh ◽  
Taichi Oyama ◽  
Yoshie Horiguchi
Keyword(s):  
Vinyl Ether ◽  
Substituent Effect ◽  
Addition Reaction ◽  
Ethyl Vinyl Ether ◽  
Ethyl Vinyl ◽  
Aromatic Substituent ◽  
Thermal Addition

A Study of Substituent Effect on the Oxidative Strengths of N-Chloroarenesulphonamides: Kinetics of Oxidation of Leucine and Isoleucine in Aqueous Acid Medium

2004 ◽  
Vol 59 (1) ◽  
pp. 63-72 ◽  
Author(s):  
Mahesha Shetty ◽  
B. Thimme Gowda
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Ionic Strength ◽  
Acid Medium ◽  
Benzene Ring ◽  
Thermodynamic Data ◽  
Substituent Effect ◽  
Kinetics Of Oxidation ◽  
Aqueous Acid ◽  
Kinetics Of

Abstract To study the variation of oxidative strengths of N-chloro-arenesulphonamides with substitution in the benzene ring, six mono- and five di-substituted N-chloro-arenesulphonamides are employed as oxidants for studying the kinetics of oxidation of two neutral amino acids, L-leucine and Lisoleucine in aqueous acid medium. The N-chloro-arenesulphonamides studied are of the constitution: ArSO2NaNCl·H2O (where Ar = C6H5, 4-CH3C6H4, 4-C2H5C6H4, 4-FC6H4, 4-ClC6H4, 4-BrC6H4, 2,3-(CH3)2C6H3, 2,4-(CH3)2C6H3, 2-CH3-4-ClC6H3, 2,4-Cl2C6H3, and 3,4-Cl2C6H3). The reactions show second order kinetics in [oxidant], fractional order in [amino acid] and inverse dependence on [H+]. Addition of the reduced product of the oxidants or variation in ionic strength of the medium has no significant effect on the rates of oxidations. A two-pathway mechanism is considered to explain the experimental results. Effective oxidizing species of the oxidants is Cl+ in different forms. Therefore the oxidising strengths of N-chloro-arenesulphonamides depend on the ease with which Cl+ is released from them. The study reveals that the introduction of substituent in the benzene ring of the oxidant affects both the kinetic and thermodynamic data for the oxidations The electron releasing groups such as CH3 generally inhibit the rates, while electron-withdrawing groups such as Cl enhance this ability, as the electron withdrawing groups ease the release of Cl+ from the reagents and hence increase the oxidising strengths. The on Ea and logA and validity of the Hammett and isokinetic relationships for the oxidations are also analysed.

Sign in / Sign up

Export Citation Format

Share Document