Reaction mass of (2R*,4R*,4aR*,9bS*)-2,4-dimethyl-4,4a,5,9b-tetrahydroindeno[1,2-d][1,3]dioxine and (2R*,4R*,4aS*,9bR*)-2,4-dimethyl-4,4a,5,9b-tetrahydroindeno[1,2-d][1,3]dioxine

Hydrolysis

Description of key information

The hydrolysis study according to OECD 111 resulted in hydrolysis < 10% after 5 d at pH 7 and 9 and 50 °C. Thus, a DT50 > 1 yr at pH 7 and 9 (25 °C) was extrapolated in accordance with the guideline. A main test was performed for pH 4 at 20, 30 and 50 °C for 31 d resulting in DT50 values of 384 d (20 °C), 78.7 d (30 °C) and 13.7 d (50 °C). Thus, the substance hydrolyses slowly under environmental conditions. 

Key value for chemical safety assessment

Half-life for hydrolysis:

1 yr

at the temperature of:

25 °C

Additional information

One experimental study was performed according to OECD 111 (GLP). A preliminary test with a concentration of approx. 250 mg/L was performed at 3 different pH values (pH 4, 7 and 9) and 50 °C for 120 h. The result from HPLC-DAD analysis indicated that the test substance is hydrolytically stable at pH 7 and 9 at 50 °C. Recovery of the substance at pH7 and pH9 was 96.15% and 100%, respectively. Thus, in accordance with the guideline no main test was considered necessary for pH 7 and 9 and the results from the preliminary test were extrapolated to 25 °C. At 25 °C the DT50 of the test substance was estimated to be > 1 yr at pH 7 and 9.
At pH 4 only 63.2% of the substance was found after 120 h in the preliminary test. Since hydrolysis was > 10% for pH4 a main test at three different temperatures (20, 30 and 50 °C) was performed. After 31 d DT50 values of 384 d (20 °C), 78.7 d (30 °C) and 13.7 d (50 °C) resulted. In conclusion, the test substance hydrolyses slowly under environmental conditions.