EPTC (Ethyl-N,N-di-n-propylthiolcarbamate) 
PEBC (Propyl-N,N-ethyl-n-butylthiolcarbamate) 
Studies showing a direct relation between the effectiveness of EPTC 
and the clay and organic matter of the soil indicated that the material 
was strongly absorbed. The data also suggested that soil microorganisms 
contributed significantly to the loss of EPTC toxicity when incorporated 
into soil (435, 495, 917, 1284). 
EPTC was hydrolyzed on standing in water. The reaction is first 
order and has an energy of activation of 7500 calories/mole (1070). 
KS Bx tot? "90%! 
= 4.25 x 107-4 (30°C) 
ei . 
Seale ee a + H_).NH + CO. + C.H-S 
-C-S- > 
ge Ne ee LOO 9 © Noha eh 
C,H, 
Studies with $?°-labeled EPTC showed that this material is readily 
absorbed from the soil, translocated throughout the entire plant, and 
rapidly metabolized (433, 434, 1524). No metabolites were identified. 
Labeled studies with PEBC showed that the metabolic breakdown in 
tomato foliage and fruits was a first-order process. The rate constant 
depended upon the tissue and the growth stage (425). 
The mechanism of adsorption of EPTC by montmorillonite was studied 
with infrared absorption. The results suggested that at least three 
mechanisms were involved (1042): 
(1) Coordination of EPTC to exchangeable metal cations 
through the carbonyl. 
(2) Coordination of EPTC to metal cations through the 
nitrogen if the molecule is sterically hindered. 
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