Photolytic oxidative demethylation of aqueous dimethylsiloxanols

Dimethylsilanediol and other water-soluble dimethysiloxanols undergo aqueous photolytic oxidative demethylation with tropospheric ultraviolet radiation in the presence of suitable chromophores, such as nitrogen oxides, to give silicic acid and carbon dioxide. The “biosuitability” of the resulting silicic acid was demonstrated by monitoring the growth of diatoms (Navicula pelliculosa) in the irradiated aqueous media. Thus, a plausible route for the further degradation of such water soluble hydrolysis products of poly(dimethyl-siloxane) to naturally occurring materials was conclusively demonstrated. Furthermore, di- and monomethyl silanol species were shown not to be utilized by the diatom colony, even when present as completely water soluble components.