Dichloro(diphenyl)silane

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2001

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

Principles of method if other than guideline:

The study was conducted at 1.5 °C ± 0.5 °C to slow the hydrolysis reaction rate.

GLP compliance:

no

Radiolabelling:

no

Analytical monitoring:

yes

Buffers:

Buffer solutions of known pH and concentration were prepared by titration of acetic acid, sodium phosphate monobasic and boric acid solution with sodium hydroxide solution. Constant ionic strength of 0.5 M was maintained for buffers by the addition of volumes of 5 M sodium nitrate solution.

Number of replicates:

One replicate per pH level

Transformation products:

not specified

Details on hydrolysis and appearance of transformation product(s):

pH 4: t1/2= 6s, pH 7: t1/2= 10s, pH 9: t1/2= 8s

pH:

4

Temp.:

1.5 °C

DT50:

0.1 min

pH:

7

Temp.:

1.5 °C

DT50:

0.167 min

pH:

9

Temp.:

1.5 °C

DT50:

0.133 min

No rate constant or definative t1/2 determined due to rapidity of hydrolysis (sparse data points for 20-70% hydrolysed). Upper limit t1/2 estimated (assuming first hydrolysis step is rate-limiting). Observation of stable[Cl-] was used to estimate t1/2; assumed 10 half-lives = exhaustive hydrolysis.

Conclusions:

The half life of the test substance was reported to be 6 seconds at pH 4, 10 seconds at pH 7 and 8 seconds at pH 9.

Description of key information

DT50 = 10 seconds at pH 7 and 1.5 °C (OECD 111)

Key value for chemical safety assessment

Half-life for hydrolysis:

0.167 min

at the temperature of:

1.5 °C

Additional information

A reliable study according to OECD guideline 111 is available for the substance dichloro(diphenyl)silane. The half-life of the test substance at 1.5 °C was reported to be 6 seconds at pH 4, 10 seconds at pH 7 and 8 seconds at pH 9. The hydrolysis products are diphenylsilanediol and hydrochloric acid.