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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

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Description of key information

From the read across with 1,3 (or 1,4)-bis[1-(tert-butylperoxy)-1-methylethyl]benzene, extrapolated values at 25°C (using the Arrhenius equation):

pH 4 : half-life = 56.4 d
pH 7: half-life = 74.7 d
pH 9: half-life = 96.5 d

Key value for chemical safety assessment

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

Additional information

There is no data on 1,4-bis[1-(tert-butylperoxy)-1-methylethyl]benzene. A read across approach is proposed with 1,3 (or 1,4)-bis[1-(tert-butylperoxy)-1-methylethyl]benzene.

The hydrolysis of [1,3(or 1,4)-phenylenebis(1-methylethylidene)]bis[1,1-dimethylethyl] peroxide was evaluated in a study performed in accordance with OECD testing guideline 111 and EPA OPPTS 835.2110 under GLP requirements.


The results from the hydrolysis test indicate that 64.6, 71.4 and 77.3% of the reaction were observed after 5 days at pH 4, 7 and 9 solutions respectively, at 50 °C. The test has demonstrated that the substance is hydrolytically stable at pH 2.6 after 24 hours. The degradation rates were calculated using first order kinetics as follows:


At 50°C:


pH 4 : half-life = 7.9 d

pH 7: half-life = 10.3 d

pH 9: half-life = 13.4 d


Extrapolated values at 25°C, using the Arrhenius equation:


pH 4 : half-life = 56.4 d

pH 7: half-life = 74.7 d

pH 9: half-life = 96.5 d