Linear Free Energy Relationships between Aqueous phase Hydroxyl Radical Reaction Rate Constants and Free Energy of Activation

2011 ◽  
Vol 45 (8) ◽  
pp. 3479-3486 ◽  
Author(s):  
Daisuke Minakata ◽  
John Crittenden
Keyword(s):  
Free Energy ◽  
Hydroxyl Radical ◽  
Rate Constants ◽  
Reaction Rate ◽  
Radical Reaction ◽  
Linear Free Energy Relationships ◽  
Reaction Rate Constants ◽  
Linear Free Energy ◽  
Free Energy Of Activation ◽  
Energy Relationships

scholarly journals Iron(III) hydroxocomplex - methyl viologen dication system as a prospective tool for determination of hydroxyl radical reaction rate constants with environmental pollutants

2021 ◽  
Author(s):  
Yuliya Tyutereva ◽  
Vyacheslav P. Grivin ◽  
Jing Xu ◽  
Feng Wu ◽  
Victor Plyusnin ◽  
...  
Keyword(s):  
Hydroxyl Radical ◽  
Hydroxyl Radicals ◽  
Rate Constants ◽  
Reaction Rate ◽  
Methyl Viologen ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Radical Reaction ◽  
Reaction Rate Constants ◽  
Wide Range

Abstract Reactivity of oxidative species with target pollutants is one of the crucial parameters for application of any system based on advanced oxidation processes (AOPs). This work presents new useful approach how to determine the hydroxyl radical reaction rate constants (kOH) using UVA laser flash photolysis technique. Fe(III) hydroxocomplex at pH 3 was applied as a standard source of hydroxyl radicals and methyl viologen dication (MV2+) was used as selective probe for •OH radical. Application of MV2+ allows to determine kOH values even for compounds which do not generate themselves optically detectable transient species in reaction with hydroxyl radicals. Validity of this approach was tested on a wide range of different persistent pesticides and its main advantages and drawbacks in comparison with existing steady-state and time-resolved techniques were discussed.

Hydrolysis of amides. VI. Dilute acid hydrolysis of N-alkyl substituted acetamides

1972 ◽  
Vol 25 (2) ◽  
pp. 303 ◽  
Author(s):  
PD Bolton ◽  
J Ellis ◽  
RD Frier ◽  
PC Nancarrow
Keyword(s):  
Free Energy ◽  
Acid Hydrolysis ◽  
Rate Constants ◽  
Rate Data ◽  
Linear Free Energy Relationships ◽  
Dilute Acid ◽  
Dilute Acid Hydrolysis ◽  
Linear Free Energy ◽  
Energy Relationships ◽  
Hydrolysis Of

Enthalpies and entropies of activation have been derived from rate constants measured over a range of temperature for the dilute acid hydrolysis of N-methyl- acetamide, N-ethylacetamide, N-n-propylacetamide, N-isopropylacetamide, N-n-butylacetamide, N-s-butylacetamide, N-isobutylacetamide, N-isopentyl-acetamide, N-n-hexylacetamide, N-cyclohexylacetamide, and N-benzylacetamide. An analysis of the rate data in terms of several Taft-type linear free energy relationships indicates that the change in steric environment which a substituent experiences when it is moved from the acyl part to the alkyl part of an amide is quantitatively similar to the change in steric environment experienced by the same substituent in moving from the acyl to the alkyl portion of an ester. Evidence is also presented that the change in six-number makes the greatest contribution to the change in steric environment.

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