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Physical & Chemical properties

Water solubility

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Description of key information

Water solubility (substance): Not relevant
Water solubility (silanol hydrolysis product, dimethylsilanol): 6200 mg/L at 20°C
Water solubility (silanol hydrolysis product, dimethylsilanediol): 430,000 mg/L at 20°C

Key value for chemical safety assessment

Additional information

The requirement to test the substance for water solubility is waived because in contact with water the substance rapidly hydrolyses very rapidly.

The water solubilities of the hydrolysis products dimethylsilanol and dimethylsilanediol are relevant. Values of 6200 mg/l and 1,000,000 mg/l at 20°C have been calculated for dimethylsilanol and dimethylsilanediol, respectively, using an appropriate QSAR.

In practice, the water solubility of the silanols is limited by their tendency to undergo condensation reactions to form siloxanes. A highly cross-linked gel may form. Significant condensation is not expected at concentrations < approx. 100 mg/l, but is dependent on specific conditions.