Characteristic of the Agent

PAE’s are the esters of benzene ortho dicarboxylic acid, which is created commercially from phthalic anhydride and an alcohol. I In general, PAE’s are colorless liquids, have high boiling points, low volatility, and are lipophilic. I

Phthalate esters are molecules consisting of phthalic acid joined together by variable length alkyl side chains via an ester bond. II Phthalates used as plasticizers are usually diesters. Diethyl phthalate and Di-n-butyl phthalate are regarded as low molecular weight (MW) phthalate esters while Bis-2-ethylhexyl phthalate and Di-isononyl phthalate are high molecular weight. III The low MW phthalates are reasonably soluble in water, but the high MW ones are only sparingly soluble. For example the water solubility of DEHP is only 0.003 mg/l. I Conversely, the affinity of the high MW phthalates to partition into fats, and be adsorbed onto and into organic and/or soil particulates is much greater than for the low MW phthalates.

Phthalate are therefore fat-soluble and seem to concentrate in materials such as butter, margarine and cheese. In addition, they will concentrate in human body fat. Since phthalates metabolize rapidly, they can be excreted through urine and feces. I