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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

PBT assessment

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Administrative data

PBT assessment: overall result

di-tert-butyl 1,1,4,4-tetramethylbut-2-yn-1,4-ylene diperoxide
Type of composition:
legal entity composition of the substance
State / form:
Reference substance:
di-tert-butyl 1,1,4,4-tetramethylbut-2-yn-1,4-ylene diperoxide
PBT status:
the substance is not PBT / vPvB

The half-life of the test item in freshwater at pH 7 is 9 days, therefore, the test item is hydrolytically unstable. Tert-butanol (CAS 75-65-0) was detected as degradation product after hydrolysis. The degradation product of the test item is inherently biodegradable, therefore, the test item is not considered to be persistent (not P/vP).

The logKow of the test item was determined to be 6.71 (above the set threshold) but the degradation product has a logKow of 0.32. This shows that there is low potential of bioaccumulation. Therefore, the test item is not considered to be B or vB substance.

The NOEC in the algae growth inhibition study was determined based on measured concentration to be 1.88 mg/L, which is above the set threshold for toxic substances. The degradation product showed no effects at concentration below 100 mg/L in all aquatic long-term studies. The test item and its degradation product are not classified as CMR substance and are not classified for specific target organ toxicity after repeated exposure (STOT RE Cat. 1 or 2). Therefore, the test item is not regarded as toxic (not T).

In conclusion, the test item is not considered to be a PBT/vPvB substance.