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Environmental fate & pathways

Hydrolysis

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Description of key information

In reliable guideline studies, the structural analogue C12-16 ADBAC proved to be hydrolytically stable with a half-life equal to or greater than one year at pH 4, 7 and 9 at ambient temperatures. C12-14 ADBAC is expected to have a similar hydrolysis profile. 

Key value for chemical safety assessment

Half-life for hydrolysis:
1 yr
at the temperature of:
20 °C

Additional information

In a guideline study, hydrolytic stability of the read-across substance C12-16 ADBAC was determined in buffer solutions of pH 4.0, 7.0 and 9.0 in a water bath at 50ºC for 5 days. Samples were taken at t0 and at regular intervals afterwards to determine half-life (t½). If t½ is less than 2.4 hours, or if less than 10% of the test substance is hydrolysed in 5 days, no further tests need to be performed at that pH. After 5 days at 50°C, less than 10% decrease in test substance concentration was measured at all three pH values. It was therefore concluded that test substance was hydrolytically stable, with a half-life equal to or greater than one year at pH 4, 7 and 9 at ambient temperature (Geurts MGJ et al.,1996).

In another guideline study, the hydrolysis of C12-16 ADBAC as a function of pH at 25°C was investigated. Hydrolysis rate constants and the half-lives for degradation were determined in aqueous buffered solutions of pH 5, 7 and 9 at 25±1°C. Two pH 7 buffers were employed during the study to evaluate buffer catalysis of the degradation process. All experiments were conducted for a 30 day study period at a nominal test concentration of 0.01 mg/mL. The measured pH values in the four buffer systems indicated that they were properly prepared and stable for the duration of the study. The results demonstrated that no significant degradation of the test substance occurred over the pH range of 5 to 9 at 25°C. The mean total recovery of the substance was 96.3%. Further, an accurate estimate of half-life for the hydrolysis could not be determined since no significant degradation of the test substance was detected during the 30 day evaluation period. Under the conditions of the study, C12-16 ADBAC was determined to be hydrolytically stable (Carpenter M and Fennessey M, 1988).