The hydrolysis of a monolayer of di-2-ethylhexyl-phthalate, adsorbed on various atmospheric model aerosol materials.

A hydrolysis of di-(2-ethylhexyl-)phthalate (DEHP) is observed to occur, when this compound is adsorbed on highly disperse powders of Al203, Fe2O2 and TiO2, leading to initial half-lives of DEHP ranging from less than one to 30 days. The decay is self-inhibited, and it slows down to half-lives ranging from 4 to 140 d. No hydrolysis can be detected with fly ash from a coal power plant and with SiO2 (Aerosil). Mono-(2-ethylhexyl-)-phtalate (MEHP) is observed to be an intermediate, the hydrolysis of MEHP is observed to occur with half-lives ranging from 25 to 2300 d, leading to phthalic acid as final product. (ITA)