scholarly journals Using Variable and Fixed Topological Indices for the Prediction of Reaction Rate Constants of Volatile Unsaturated Hydrocarbons with OH Radicals

Molecules ◽  
2004 ◽  
Vol 9 (12) ◽  
pp. 1160-1176 ◽  
Author(s):  
Matevž Pompe ◽  
Marjan Veber ◽  
Milan Randić ◽  
Alexandru Balaban
Keyword(s):  
Rate Constants ◽  
Reaction Rate ◽  
Topological Indices ◽  
Oh Radicals ◽  
Unsaturated Hydrocarbons ◽  
Reaction Rate Constants

Reactions of tert-C4H9+, tert-C5H11+, and CH3-cy-C5H9+ ions with pentenes

1976 ◽  
Vol 54 (19) ◽  
pp. 3050-3055 ◽  
Author(s):  
Guy J. Collin
Keyword(s):  
Proton Transfer ◽  
Rate Constants ◽  
Hydrogen Molecule ◽  
Reaction Rate ◽  
Transfer Reaction ◽  
Proton Transfer Reaction ◽  
Unsaturated Hydrocarbons ◽  
Total Reaction ◽  
Reaction Rate Constants ◽  
Isomerization Mechanism

Total reaction rate constants for the disappearance of tert-C4H9+ ions with five C5H10 unsaturated hydrocarbons were determined by comparing the rate of formation of isobutane in the radiolysis of neopentane in the presence of various additives. These rate constants are of the order of 5 to 1.35 × 10−10 cm3 molecule−1 s−1 depending upon the olefin under investigation. The hydride transfer reaction from 3-methyl-1-butene and trans-2-pentene toward the tert-C4H9+ ion was also observed, as was the proton transfer reaction from the tert-C4H9+ ion toward 2-methyl-2-butene and 2-methyl-1-butene. In the latter two cases, a significant isomerization of methylbutene is noticed: an isomerization mechanism based upon the reactions of tert-C5H11+ ions is tentatively suggested. Finally, the transfer reaction of an hydrogen molecule between the CH3-cy-C5H9+ ion and the methylbutenes is observed during the radiolysis of methylcyclopentane.

scholarly journals Indirect Photodegradation of Sulfamethoxazole and Trimethoprim by Hydroxyl Radicals in Aquatic Environment: Mechanisms, Transformation Products and Eco-Toxicity Evaluation

2020 ◽  
Vol 21 (17) ◽  
pp. 6276
Author(s):  
Jiaoxue Yang ◽  
Guochun Lv ◽  
Chenxi Zhang ◽  
Zehua Wang ◽  
Xiaomin Sun
Keyword(s):  
Rate Constants ◽  
Aquatic Environment ◽  
Reaction Rate ◽  
Theoretical Calculations ◽  
Theoretical Models ◽  
Transformation Products ◽  
Initial Reaction ◽  
Oh Radicals ◽  
Reaction Rate Constants ◽  
Insight Into

The bacteriostatic antibiotics, sulfamethoxazole (SMX) and trimethoprim (TMP), have frequently been found in wastewater and surface water, which raises the concerns about their ecotoxicological effects. The indirect photochemical transformation has been proven to be an efficient way to degrade SMX and TMP. In this study, the reaction mechanisms of the degradation by SMX and TMF by OH radicals were investigated by theoretical calculations. Corresponding rate constants were determined and the eco-toxicity of SMX and TMP and its degradations products were predicted using theoretical models. The results indicate that the most favorable pathways for the transformation of SMX and TMP are both •OH-addition reaction of benzene ring site with lowest Gibbs free energy barriers (6.86 and 6.21 kcal mol−1). It was found that the overall reaction rate constants of •OH-initial reaction of SMX and TMP are 1.28 × 108 M−1 s−1 and 6.21 × 108 M−1 s−1 at 298 K, respectively. When comparing the eco-toxicity of transformation products with parent SMX and TMP, it can be concluded that the acute and chronic toxicities of the degraded products are reduced, but some products remain harmful for organisms, especially for daphnid (toxic or very toxic level). This study can give greater insight into the degradation of SMX and TMP by •OH through theoretical calculations in aquatic environment.

Measurement of the OH Reaction Rate Constants for CF3CH2OH, CF3CF2CH2OH, and CF3CH(OH)CF3

1999 ◽  
Vol 103 (15) ◽  
pp. 2664-2672 ◽  
Author(s):  
Kazuaki Tokuhashi ◽  
Hidekazu Nagai ◽  
Akifumi Takahashi ◽  
Masahiro Kaise ◽  
Shigeo Kondo ◽  
...  
Keyword(s):  
Rate Constants ◽  
Reaction Rate ◽  
Reaction Rate Constants

scholarly journals PREDICTION OF REACTION RATE CONSTANTS OF HYDROXYL RADICAL WITH ORGANIC COMPOUNDS

2014 ◽  
Vol 59 (1) ◽  
pp. 2252-2259 ◽  
Author(s):  
ZHEN CHEN ◽  
XINLIANG YU ◽  
XIANWEI HUANG ◽  
SHIHUA ZHANG
Keyword(s):  
Hydroxyl Radical ◽  
Organic Compounds ◽  
Rate Constants ◽  
Reaction Rate ◽  
Reaction Rate Constants
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