STP1347: Pesticide Stability Versus Clay Carrier Surface Acidity

    Taylor, DR
    Director of Research, Senior Research Scientist and Research Technician, Oil-Dri Corporation of American, Vernon Hills, IL

    Stein, J
    Director of Research, Senior Research Scientist and Research Technician, Oil-Dri Corporation of American, Vernon Hills, IL

    Svidovsky, N
    Director of Research, Senior Research Scientist and Research Technician, Oil-Dri Corporation of American, Vernon Hills, IL

    Pages: 13    Published: Jan 1998


    Abstract

    Clay granules are well known as carriers for a broad range of pesticides including various insecticides, herbicides and fungicides. Although they generally function quite well in this applications, formulations utilizing chemically sensitive pesticides must often be augmented with organic deactivators such as dipropylene glycol, polypropylene glycol, etc. in order to stabilize the system against degradation of the active ingredient. The present paper reports on the use of clay carriers which have been processed in a new way that significantly enhances their chemical inertness by modifying surface activity (i.e.surface acidity). This objective has been realized without compromising hardness or liquid holding capacity. Utilizing these materials, we have attempted to draw a correlation between pesticide stability (measured as pKa value of first hydrolysis decomposition products) and carrier surface acidity. A number of well-known pesticide molecules chosen from the phosphate ester and thiocarbamate classes have been used to illustrate these correlations.

    Keywords:

    granules, clay-based pesticide carriers, pesticide degradation, pesticide pKa values


    Paper ID: STP14167S

    Committee/Subcommittee: E35.22

    DOI: 10.1520/STP14167S


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