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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Physical & Chemical properties

Dissociation constant

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Administrative data

Link to relevant study record(s)

Reference
Endpoint:
dissociation constant
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Justification for type of information:
Please refer to additional information field in the endpoint study summary (Dissociation constant).
Reason / purpose for cross-reference:
read-across source
Dissociating properties:
yes
No.:
#1
pKa:
9.6
Temp.:
22 °C
Remarks on result:
other: ±0.3
No.:
#2
pKa:
> 11
Temp.:
22 °C
Remarks on result:
other: Estimate
No.:
#3
pKa:
> 11
Temp.:
22 °C
Remarks on result:
other: Estimate

Description of key information

Dissociation constant (parent): not relevant

Silanol hydrolysis product: approximately 10 (read-across from phenylsilanetriol)

Key value for chemical safety assessment

Additional information

The requirement to test the substance for dissociation constant is waivedbecause there are no ionizable groups present in the molecule. In contact with water the substance will hydrolyse to form propylsilanetriol and ethanol.

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 or in vivo. Phenylsilanetriol has a measured first dissociation constant ca. 10 in a reliable study using a relevant test method (reliability 1; read across conclusion is given reliability 2).