Chlorodimethyloctylsilane

Hydrolysis

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2015-03-13

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

according to guideline

Guideline:

EU Method C.7 (Degradation: Abiotic Degradation: Hydrolysis as a Function of pH)

Principles of method if other than guideline:

Screening method based on 1H-NMR spectroscopy.

GLP compliance:

no

Remarks:

ISO 9001:2008

Analytical monitoring:

not specified

Buffers:

- pH: 4
CertiPur, Citric acid + hydrochloric acid + sodium hydroxide, company Merck


- pH: 7
Baker Analyzed, Potassium dihydrogen phosphate + disodiumhydrogen phosphate, company J. T. Baker


- pH: 9
CertiPur, Boronic acid + potassium chloride + sodium hydroxide, company Merck

Transformation products:

no

pH:

4

Temp.:

25 °C

Remarks on result:

other: Half-life <<2 minutes

pH:

7

Temp.:

25 °C

Remarks on result:

other: Half-lfe <<2 minutes

pH:

9

Temp.:

25 °C

Remarks on result:

other: Half-life <<2 minutes

Other kinetic parameters:

None determined.

Details on results:

A determination of the hydrolysis kinetics was not possible since suitable samples for 1H NMR spectroscopic measurements could not be prepared because of very fast hydrolysis and precipitation of solids. The half-life times were thus assumed to be much smaller than 2 min.

Conclusions:

Hydrolysis half-lives of <<2 min at pH 4, pH 7 and pH 9 and 25°C were determined in a non-guideline study conducted according to generally accepted scientific principles. The result is considered to be reliable.

Reference 2

Endpoint:

hydrolysis

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 for cross-reference:

read-across source

Transformation products:

not specified

pH:

4

Temp.:

25 °C

Remarks on result:

other: Half-life <<2 minutes

pH:

7

Temp.:

25 °C

Remarks on result:

other: Half-lfe <<2 minutes

pH:

9

Temp.:

25 °C

Remarks on result:

other: Half-life <<2 minutes

Other kinetic parameters:

None determined.

Description of key information

Hydrolysis half-life: < 2 min (EU method C.7)

Additional information

No data on the hydrolysis of chloro(dimethyl)octylsilane (CAS 18162-84-0) are available. Therefore good quality data from the similar substance trichloro(trimethylpentyl)silane (CAS 18379-25-4) were read across. 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.

The hydrolysis study for the trichloro(trimethylpentyl)silane (CAS 18379-25-4) was performed according to EC test guideline C.7 (in analogy to OECD test guideline 111). A determination of the solubility of the read across substance in water and its hydrolysis kinetics was not possible since suitable samples for kinetic 1H NMR spectroscopic measurements could not be prepared due to very fast hydrolysis and precipitation of solids. The half-life was thus assumed to be much lower than 2 min. This result is in line with other chlorosilanes, for which measured data are available (see supporting information).

On this basis the hydrolysis of the substance is expected to be very fast and the hydrolysis products are (dimethyl)octylsilanol and hydrochloric acid.