Main Title |
New Perspectives on the Hydrolytic Degradation of the Organophosphorothioate Insecticide Chlorpyrifos. |
Author |
Macalady, D. L. ;
Wolfe, N. L. ;
|
CORP Author |
Colorado School of Mines, Golden.;Environmental Research Lab., Athens, GA. |
Year Published |
1983 |
Report Number |
EPA-600/J-83-169; |
Stock Number |
PB84-171024 |
Additional Subjects |
Hydrolysis ;
Degradation ;
Water pollution ;
Pesticides ;
Insecticides ;
Reaction kinetics ;
pH ;
Phosphorothioates ;
Phosphorus organic compounds ;
Reprints ;
Dursban ;
Ecosystems
|
Holdings |
Library |
Call Number |
Additional Info |
Location |
Last Modified |
Checkout Status |
NTIS |
PB84-171024 |
Some EPA libraries have a fiche copy filed under the call number shown. |
|
07/26/2022 |
|
Collation |
11p |
Abstract |
The disappearance kinetics in water for chlorpyrifos (O,O-diethyl O-(3,5,6-trichloro-2-pyridyl) phosphorothioate), an important insecticide, has been investigated to provide a kinetic expression to define the hydrolysis process in aquatic ecosystems. Pseudo-first-order kinetics are observed over the pH range of 1-13. The rate constant is independent of pH from pH 1 to pH 7 and has a value of (6.2 + or - 0.9) x 10 to the 6th power/min at 25 deg. C. At alkaline pHs, the rate constant is much larger but is not directly proportional to hydroxide activity. The observed behavior over the pH range 10-12 is consistent, however, with equilibrium formation of a 5-coordinate charged hydroxyphosphorothioate intermediate and the rate-controlling decomposition of this intermediate to products. Thus, the second-order rate expression does not accurately describe the kinetics of degradation at alkaline pHs. Product studies over the alkaline pH range (9-13) show that the only major products are 3,5,6-trichloro-2-pyridinol and O,O-diethyl phosphorothioic acid. (Copyright (c) 1983 by the American Chemical Society.) |
Availability Notes |
Pub. in Jnl. of Agricultural and Food Chemistry v31, n6 p1139-1147 1983. |
NTIS Title Notes |
Journal article. |
Title Annotations |
Reprint: New Perspectives on the Hydrolytic Degradation of the Organophosphorothioate Insecticide Chlorpyrifos. |
PUB Date Free Form |
c1983 |
Category Codes |
7D; 68D; 68E; 99F |
NTIS Prices |
Not available NTIS |
Primary Description |
600/01 |
Document Type |
NT |
Cataloging Source |
NTIS/MT |
Control Number |
416024019 |
Origin |
NTIS |
Type |
CAT |