Radiation-sensitized Thermal Cracking of n-Butane. I. Radical Reactions

1974 ◽  
Vol 52 (14) ◽  
pp. 2579-2589 ◽  
Author(s):  
Shingo Matsuoka ◽  
Takaaki Tamura ◽  
Keichi Oshima ◽  
Yunosuke Oshima
Keyword(s):  
Activation Energy ◽  
Main Chain ◽  
Thermal Cracking ◽  
Chain Termination ◽  
Chain Mechanism ◽  
Radical Chain ◽  
Chain Termination Reaction ◽  
Ammonia Addition ◽  
Ethyl Radicals ◽  
Cracking Products

The radiolysis of n-butane was investigated at temperatures ranging from 17 to 548 °C in both static and flow systems.It was concluded that in the radiation-sensitized thermal cracking region the main products, methane, ethane, ethylene, and propylene, were formed by a radical chain mechanism. The conclusion was reached from comparison with the thermal cracking products, the effect of ammonia addition, the dose rate dependence, and in particular the correlation between the temperature change of the type of the main chain-termination reaction and that of the activation energy of propylene formation. The value of the activation energy for propylene formation showed that the main chain-termination reaction at temperatures between 410 and 520 °C was a combination reaction of ethyl radicals. The major part of 1-butene, trans-2-butene, and cis-2-butene, formed in the chain region, was shown to result from the thermal decomposition of the chain carrying butyl radicals.Rate parameters for some of the reactions involved were calculated.

The pyrolysis of propylene

1967 ◽  
Vol 300 (1460) ◽  
pp. 120-139 ◽  
Keyword(s):  
Main Chain ◽  
Initial Pressure ◽  
Pressure Change ◽  
Chain Termination ◽  
Radical Mechanism ◽  
Reaction Products ◽  
Secondary Products ◽  
Free Radical Mechanism ◽  
Chain Termination Reaction ◽  
The Many

Detailed analyses of the reaction products of the pyrolysis carried out in the temperature range 555 to 640°C, at initial pressures between 7 and 300 mmHg, and measurements of overall pressure change have shown that the overall pyrolysis may be described by the expression -d[C 3 H 6 ]/d t = 10 14.06 [C 3 H 6 ] 1.4 exp (-58600/ RT ) mole ml. -1 s -1 . Twenty three primary and three secondary products of the pyrolysis at 600°C and an initial pressure of 103 mmHg have been determined at six extents of reaction up to 12%. On the basis of these measurements a long chain free radical mechanism is proposed in which reactions of the 1-methyl-4-pentenyl radical are of prime importance. The main chain termination reaction is found to be combination of methyl and allyl radicals. It is concluded that radical combination reactions involving allyl are considerably slower than those involving alkyls. Steady-state treatment of the data is precluded by their complexity. Speculative routes to the formation of the many higher products are suggested.

scholarly journals Antioxidant activity and mechanism of inhibitory action of gentisic and α-resorcylic acids

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Azadeh Mardani-Ghahfarokhi ◽  
Reza Farhoosh
Keyword(s):  
Antioxidant Activity ◽  
Rate Ratio ◽  
Inhibitory Action ◽  
Main Chain ◽  
Average Rate ◽  
Chain Termination ◽  
Molecular Structures ◽  
Side Reactions ◽  
Oil In Water ◽  
Chain Termination Reaction

Abstract The antioxidant activity of gentisic (GA) and α-resorcylic (α-RA) acids was investigated by considering their molecular structures in various oxidative environments, including DPPH· scavenging assay, stripped olive and soybean oils, and the corresponding oil-in-water emulsions. The mechanism of action in the oils was evaluated in the presence of different concentrations of the antioxidants at 60 °C, using the kinetic parameters the stabilization factor (F), the oxidation rate ratio (ORR), the activity (A), and the average rate of antioxidant consumption ($$\overline{r}_{{{\text{AH}}}}$$ r ¯ AH ). GA was significantly more potent antioxidant than α-RA in all the environments. Although the less polar α-RA showed better activity in the emulsions rather than in the bulk oils, GA with an ortho-hydroxy structure had higher capacity to scavenge DPPH·, and LOO· in the oils and emulsions. The lower performance of α-RA was attributed to its participation in side reactions of chain initiation (AH + LOOH → A· + L· + H2O) and propagation (A· + LH → AH + L·) as competed with the main chain termination reaction (LOO· + AH → LOOH + A·).

Calculation of reaction order for the homogeneous pyrolysis of organic vapors

1969 ◽  
Vol 47 (14) ◽  
pp. 2707-2712 ◽  
Author(s):  
John Torok ◽  
Samuel Sandler
Keyword(s):  
Free Radical ◽  
Reaction Order ◽  
Chain Termination ◽  
Recombination Reaction ◽  
Mathematical Equation ◽  
Methyl Radical ◽  
Radical Chain ◽  
Organic Vapors ◽  
Chain Reactions ◽  
Chain Termination Reaction

A method is proposed for the derivation of a mathematical equation that relates the kinetic parameters of the propagation reactions of homogeneous free-radical chain reactions to the overall order of the reaction. The equation may be used in evaluating the predominant chain-termination reaction, provided that the mechanism of propagation of the chain is well understood. Application of the technique is demonstrated for the pyrolysis of n-butane. It predicts the predominance of the methyl–methyl radical recombination reaction.

In Vitro Analysis of the Chain Termination Reaction in the Synthesis of Poly-(R)-β-hydroxybutyrate by the Class III Synthase fromAllochromatiumvinosum

2005 ◽  
Vol 6 (4) ◽  
pp. 2113-2119 ◽  
Author(s):  
Adam G. Lawrence ◽  
JoonHo Choi ◽  
ChoKyun Rha ◽  
JoAnne Stubbe ◽  
Anthony J. Sinskey
Keyword(s):  
Chain Termination ◽  
Class Iii ◽  
Chain Termination Reaction ◽  
Vitro Analysis ◽  
In Vitro Analysis

scholarly journals In VitroReconstruction of the Chain Termination Reaction in Biosynthesis of theEscherichia coliO9aO-Polysaccharide

2011 ◽  
Vol 286 (48) ◽  
pp. 41391-41401 ◽  
Author(s):  
Bradley R. Clarke ◽  
Michele R. Richards ◽  
Laura K. Greenfield ◽  
Dianjie Hou ◽  
Todd L. Lowary ◽  
...  
Keyword(s):  
Chain Termination ◽  
Chain Termination Reaction

Application of a colorimetric chain-termination assay for characterization of reverse transcriptase from 3′-azido-2′,3′-deoxythymidine-resistant HIV isolates

2002 ◽  
Vol 35 (3) ◽  
pp. 155 ◽  
Author(s):  
Xing-Wu Shao ◽  
Sandra Hjalmarsson ◽  
Johan Lennerstrand ◽  
Bo Svennerholm ◽  
Jonas Blomberg ◽  
...  
Keyword(s):  
Reverse Transcriptase ◽  
Chain Termination
Sign in / Sign up

Export Citation Format

Share Document