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Hydrolysis was assessed with regards to stability by read-across to MAES.

The determination was carried out using Method C7 of Commission Directive 92/69/EEC (which constitutes Annex V of Council Directive 67/548/EEC).

The kinetics of the study have been determined to be consistent with that of a pseudo-first order reaction as the graphs of log10 concentration versus time are straight lines. It has been observed that the rate of hydrolysis increases with an increase in pH. The hydrolysis pathway was anticipated to be base catalysed hydrolysis/cleavage of the test material at either of the two ester bonds. Therefore possible primary hydrolysis products may be, but not limited to: • Butanedioic acid • 2 -Propenoic acid, 2 -hydroxyethyl ester • 2-Propenoic acid • Butanedioic acid, mono 2-hydroxyethyl ester.

It has been observed that the rate of hydrolysis increases with an increase in pH.

The rate constant and estimated half-life at 25°C of the test material are shown in the following table:

pH

Rate Constant (s-1)

Estimated Half-life at 25oC

4

2.72 x 10-8

295 days

7

5.13 x 10-8

156 days

9

4.14 x 10-6

46.5 hours

The estimated half-life at 25oC 295 days (pH = 4), 156 days (pH = 7) and 46.5 hours (pH = 9) indicates that significant exposure to the parent compound in the environment over a long period of time is not of significant concern.