6-diazo-5,6-dihydro-5-oxonaphthalene-2-sulphonyl chloride

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Qualifier:

according to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

GLP compliance:

yes

Analytical monitoring:

yes

Buffers:

pH 4:
21.01 g citric acid monohydrate was dissolved in 200 ml sodium hydroxide solution (c = 1 mol/l). This solution was filled up to a volume of 1000 ml with demineralized water. 44 ml of hydrochloric acid (c = 1 mol/l) was added to 560 ml of this solution and filled up to a volume of 1000 ml with demineralized water. The pH value of the buffer solution was adjusted to pH 4 for each hydrolysis temperature.
pH 7:
13.61 g potassium dihydrogen phosphate was dissolved in 1000 ml demineralized water. 30 ml of sodium hydroxide solution (c = 1 mol/l) was added to 500 ml of this solution and filled up to a volume of 1000 ml with demineralized water. The pH of the buffer solution value was adjusted to pH 7 for each hydrolysis temperature.
pH 9:
7.46 g potassium chloride and 6.18 g boric acid were dissolved in 1000 ml demineralized water. 21 ml of sodium hydroxide solution (c = 1 mol/l) was added to 500 ml of this solution and filled up to a volume of 1000 ml with demineralized water. The pH value of the buffer solution was adjusted to pH 9 for each hydrolysis temperature.

Preliminary study:

The water solubility of the test item is 4.4 g/l (see report PS20170329-4). Solutions of the test item were prepared by dissolving the test item in acetonitrile. These solutions were filled up to 50 ml with the relevant buffers.


Amount of test item /mg at different pH:
pH 4 18.8 Test item precipitated after addition of buffer solution
pH 7 25.4 Test item precipitated after addition of buffer solution
pH 9 13.1 est item precipitated after addition of buffer solution

For a hydrolysis study it is necessary to trace the hydrolysis down to 10 % of the initial weight of the test item. Therefore at least the tenfold amount of the detection limit has to be dissolved in the relevant buffer solution. For this test item the detection limit was determined to be 0.85 mg/l (see chapter 4.4.2). However using the tenfold amount of the detection limit led to precipitation of the test item after addition of the relevant buffer solution. Therefore the hydrolysis test was not feasible.

Transformation products:

not measured

Key result

Remarks on result:

not determinable because of methodological limitations

Validity criteria fulfilled:

not applicable

Conclusions:

Using the tenfold amount of the detection limit led to precipitation of the test item after addition of the relevant buffer solution. Therefore, the hydrolysis test was not feasible.

Description of key information

Using the tenfold amount of the detection limit led to precipitation of the test item after addition of the relevant buffer solution. Therefore, the hydrolysis test was not feasible.