Bromoform

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Experimental Phase: 08 January 2018 to 29 June 2018. Report Issued: 28 August 2018.

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)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

Duplicate sample solutions were taken initially and from the water bath samples at various time points. The pH of each solution was recorded. The concentration of test substance in the sample solutions was determined by high pressure liquid chromatography (HPLC). An aliquot of each sample solution was analysed as received.

Standards
Standard solutions of test item were prepared in acetonitrile : relevant pH buffer solution (1:99 v/v) to cover a nominal concentration range of 25 to 125 mg/L, with a duplicate at nominally 100 mg/L.

Matrix blank
Acetonitrile: relevant pH buffer solution (1:99 v/v).

Preliminary study:

The extent of hydrolysis at pH 9 and 50 °C after 120 hours indicated that in accordance with the test guideline a further test (Tier 2) was required to estimate the rate constant and half-life at 25 °C.

Transformation products:

not measured

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

As the test item is bromoform, the hydrolysis products were considered to be dibromomethanol (CAS number: 166600-78-8) and aqueous hydrobromic acid (CAS number: 10035-10-6).

Key result

pH:

4

Temp.:

25 °C

DT50:

> 1 yr

Key result

pH:

7

Temp.:

25 °C

DT50:

> 1 yr

Key result

pH:

9

Temp.:

25 °C

Hydrolysis rate constant:

0 h-1

DT50:

> 1 yr

Validity criteria fulfilled:

yes

Conclusions:

The estimated half-life of the test substance at a pH of 4 or 7 is > 1 year at 25 °C. At pH 9 the test substance estimated rate constant and half-life at 25 °C is > 1 year.

Executive summary:

Introduction

The study was conducted to determine the hydrolytic stability of the test substance at three pH’s. The method used was designed to be compatible with Method 111 of the OECD Guidelines for Testing of Chemicals, 13 April 2004.

 

Method

The test system consisted of buffer solutions at pH’s 4, 7 and 9. A preliminary test was performed where test substance solutions at pH 4, 7 and 9 were maintained at 50.0 ± 0.5 °C for a period of at least 240 hours.

Results from the Preliminary Test showed it was necessary to undertake further testing (Tier 2) at pH 9. for this further test solutions were maintained at 50.0 ± 0.5 °C, 60.0 ± 0.5 °C and 70.0 ± 0.5 °C for a period of at least 72 hours.

Results

The results were as follows:

pH	Rate Constant (hr^-1)	Estimated half-life at 25 °C
4	-	>1 year
7	-	>1 year
9	7.96 x 10^-6	> 1 year

 

 

Conclusion

The estimated half-life of the test substance at a pH of 4 or 7 is > 1 year at 25 °C.  At pH 9 the test substance estimated rate constant and half-life at 25 °C is > 1 year.

Description of key information

Hydrolytic stability of the test substance.

Key value for chemical safety assessment

Half-life for hydrolysis:

1 yr

at the temperature of:

25 °C