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Description of key information

Half-lives (DT50) at 25°C:
- t1/2 (pH4) > 1 year
- t1/2 (pH7) = 280 day(s)
- t1/2 (pH9) = 68.4 hour(s)

Key value for chemical safety assessment

Half-life for hydrolysis:
280 d
at the temperature of:
25 °C

Additional information

Since RAV 7NG contains as main ingredient 'diallyl 2,2'oxydiethyl dicarbonate' and experimental data are lacking for RAV 7NG, the experimental data from 'diallyl 2,2'oxydiethyl dicarbonate' were used in a read-across approach.

Justification for read-across from supporting substance RAV 7AT (diallyl 2,2'-oxydiethyl dicarbonate; CAS 142-22-3; EC 205-528-7): about 70 % of RAV 7NG (EC 700-483-4) consists of components that can be found in the commercial ADC grades known as RAV 7AT, Nouryset 200 and CR39. Merely from comparing the similar production processes of these two substances it is apparent that RAV 7AT and RAV 7NG are closely related to each other.  Finally, the physical-chemical, toxicological and ecotoxicological properties of RAV 7NG and RAV 7AT are almost equal and as a result, read across is justified.

The rate of hydrolysis of 'diallyl 2,2'oxydiethyl dicarbonate increases with an increase in pH, whereas the following half-lives (at 25°C) were obtained [For pH 7 and pH 9 graphs of the common logarithm of the concentration (g/L) versus time (hours) were plotted and the rate constant and half-life calculated. By plotting the natural logarithm of the rate constants against the reciprocal of the temperature (K), the rate constant and half-lives at 25°C were obtained by either interpolation or extrapolation.(Mullee, 2005)]:

- t1/2(pH4) > 1 year

Sample solutions at pH 4 were maintained at 50.0 ± 0.5°C for a period of 120 hours.Result: Less than 10% hydrolysis after 5 days at 50°C, equivalent to a half-life greater than 1 year at 25°C.

- t1/2(pH7) = 280 day(s)

Sample solutions at pH 7 were maintained at 50.0 ± 0.5°C for a period of 360 hours. Result: The extent of hydrolysis after 360 hours indicated that a further test (with solutions being maintained at 60 and 70 ± 0.5°C) was required to estimate the rate constant and half-life. Results: t1/2 = 69 h at 60 °C and t1/2 = 23.7 h at 70 °C.

- t1/2(pH9) = 68.4 hour(s)

Due to the anticipated rapid hydrolysis at pH 9, solutions were maintained at 20 and 30 ± 0.5°C. Results: t1/2 = 133 h at 20 °C and t1/2 = 36 h at 30 °C.