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Physical & Chemical properties

Surface tension

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Endpoint:
surface tension
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 the attached justification below and the overall justification for grouping of substances attached in IUCLID Section 13.
Reason / purpose:
read-across source
Surface tension:
56.35 mN/m
Temp.:
20 °C
Remarks on result:
other: measured at saturation concentration
Endpoint:
surface tension
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2011
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
comparable to guideline study with acceptable restrictions
Justification for type of information:
Refer to endpoint summary for further information.
Qualifier:
according to
Guideline:
EU Method A.5 (Surface Tension)
GLP compliance:
no
Type of method:
plate method
Surface tension:
56.35 mN/m
Temp.:
20 °C
Remarks on result:
other: measured at saturation concentration

Results:

No.

Time after transferring to the measurement vessel (min)

Measured surface tension (mN/m)

Corrected surface tension (mN/m)

1

30

56.38

-

2

35

56.34

-

3

40

56.36

-

4

45

56.34

-

5

50

56.36

-

6

55

56.36

-

7

60

56.35

-

Total mean value:

56.35

-

Mean value (state of equilibrium)

56.35

 

When preparing the test solution (100 mg/l) with the buffer solution pH 7, the substance reacts at once with water with generation of a flocculent white precipitate. After 3 days the precipitate doesn’t disappear. Before measurement at 20 °C the precipitate is removed by filtration.

Conclusions:
The substance trichloro(hexadecyl)silane hydrolyses rapidly in water to form hexadecylsilanetriol. Therefore, the surface tension of the hydrolysis product, hexadecylsilanetriol (generated by the dissolution of trichloro(hexadecyl)silane in water) was measured to be 56.35 mN/m at 20 °C (at saturation concentration). The hydrolysis product is considered to be slightly surface active.
Endpoint:
surface tension
Data waiving:
study scientifically not necessary / other information available
Justification for data waiving:
other:

Description of key information

Surface tension (dichloromethyltetradecylsilane): not relevant

Silanol hydrolysis product: approximately 56.35 mN/m at 20 °C at saturation concentration (read-across from hexadecylsilanetriol)

Key value for chemical safety assessment

Additional information

In accordance with Column 2 of REACH Annex VII (Section 7.6), the requirement to test the substance for surface tension is waived because in contact with water the substance rapidly hydrolyses to form methyltetradecylsilanediol and HCl. There are no reliable measured data for the surface tension of methyltetradecylsilanediol.

For the hydrolysis product methyltetradecylsilanediol, it is appropriate to read-across surface tension data from structurally related fatty alkyl silanes, such as hexadecylsilanetriol. Hexadecylsilanetriol has a surface tension value of 56.35 °C in a reliable study using a relevant test method (reliability 1; read across conclusion is given reliability 2). As such, it is considered to be slightly surface active.

Details on the read across justification can be found in the attached justification in the respective target entry and in the overall justification for grouping of substances attached in IUCLID Section 13.