Potential Controlled-Release Herbicides from 2,4-D Esters of Starches

Unmodified, cyanoethylated, and crosslinked corn starches were reacted with 2,4-dichlorophenoxyacetyl chloride in pyridine to produce the corresponding 2,4-D [(2,4-dichlorophenoxy)acetic acid]esters of high acyl content. Hydrolysis studies at pH 6 and 8 at ambient temperature showed that these insoluble compositions liberated varying amounts of 2,4-D and soluble 2,4-D esters by ester link and glucoside bond cleavage, respectively, at rates that indicate their possible use as controlled-release herbicides.