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Physical & Chemical properties

Dissociation constant

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Description of key information

Dissociation constant (propylsilanetriol): ca. 10

Key value for chemical safety assessment

Additional information

It is not considered technically feasible to measure the dissociation constant of tripotassium propylsilanetriolate because it is only stable in aqueous solution at high pH (the pH of the commercial product is >/=14).

There are no reliable measured data for the dissociation constant of propylsilanetriol. The typical dissociation constants for the hydroxyl protons of silanetriols are available from studies in other silanetriols. It is appropriate to read-across dissociation constant data for propylsilanetriol from phenylsilanetriol. This suggests that silanols are not expected to undergo significant dissociation within the range of pH relevant in the environment orin vivo. Phenylsilanetriol has a measured first dissociation constant of ca.10 in a reliable study using a relevant test method, (reliability 1; read-across conclusion is given reliability 2). Additional information is given in a supporting report (PFA 2013b) attached in Section 13 of the REACH technical dossier.