Synthesis of 2,4-dichlorophenoxyacetic acid: novelties of kinetics of inverse phase transfer catalysis

2002 ◽  
Vol 184 (1-2) ◽  
pp. 151-160 ◽  
Author(s):  
G.D Yadav ◽  
Yogeeta B Jadhav
2012 ◽  
Vol 78 (15) ◽  
pp. 5305-5312 ◽  
Author(s):  
Jacob Bælum ◽  
Emmanuel Prestat ◽  
Maude M. David ◽  
Bjarne W. Strobel ◽  
Carsten S. Jacobsen

ABSTRACTMineralization potentials, rates, and kinetics of the three phenoxy acid (PA) herbicides, 2,4-dichlorophenoxyacetic acid (2,4-D), 4-chloro-2-methylphenoxyacetic acid (MCPA), and 2-(4-chloro-2-methylphenoxy)propanoic acid (MCPP), were investigated and compared in 15 soils collected from five continents. The mineralization patterns were fitted by zero/linear or exponential growth forms of the three-half-order models and by logarithmic (log), first-order, or zero-order kinetic models. Prior and subsequent to the mineralization event,tfdAgenes were quantified using real-time PCR to estimate the genetic potential for degrading PA in the soils. In 25 of the 45 mineralization scenarios, ∼60% mineralization was observed within 118 days. Elevated concentrations oftfdAin the range 1 × 105to 5 × 107gene copies g−1of soil were observed in soils where mineralization could be described by using growth-linked kinetic models. A clear trend was observed that the mineralization rates of the three PAs occurred in the order 2,4-D > MCPA > MCPP, and a correlation was observed between rapid mineralization and soils exposed to PA previously. Finally, for 2,4-D mineralization, all seven mineralization patterns which were best fitted by the exponential model yielded a highertfdAgene potential after mineralization had occurred than the three mineralization patterns best fitted by the Lin model.


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