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Environmental fate & pathways

Hydrolysis

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Vanadyl pyrophophate catalysts have both Brønsted and Lewis acid sites. The acidic properties indicate that if (VO)2P207 releases into aquatic environment, the hydrolysis of dissolved (VO)2P207 may proceed eventually to vanadyl ion (VO2+) and orthophosphate (PO43-). However, with low water solubility of approx. 12 mg/L, the catalyst is considered to be stable in aquatic environments. Based on the hydrolysis study of VO2 from Wehrli et. al (1989) and the first equilibrium constant for the reaction of P2O74- in aqueous solution at pH 2 to 9 (Crowther, 1953), the hydrolysis half-life of dissolved (VO)2P207 will be one year or greater in nature water even at low pH. Therefore the rate of hydrolytic reaction of the catalyst is slow enough that significant breakdown is not important under normal environmental conditions.

Wehrli, B. and Stumm, W. (1989). Geochimica et Cosmochimica Acta, vol. 53 (1), 69-77

Crowther, J.P and Westman E.R. (1953), Can. J. Chem. Vol. 32, 42-48.