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EC number: 221-375-9 | CAS number: 3081-14-9
Hydrolysis
Administrative data
Link to relevant study record(s)
Description of key information
Read-across was performed using data from a similar paraphenylediamine 44PD (N-(1,4-dimethylpentyl)-N'-phenylbenzene-1,4-diamine) . A read-across justification using structural considerations, relevant PC-data (water solubility, logKow), fate data (biodegradation, logKoc) as well as ecotoxicological data is attached in IUCLID chapter 13.
In a read-across approach with 44PD (containing two sec. Butyl moieties instead of two 2,4-Dimethylpentyl moieties for 77PD), the substance was found to hydrolyse rapidly with half-lives of 1.5h (pH9), 5.3h (pH7) and 230h (pH4) at 20°C. The primary hydrolysis products are 44-QDI (oxidised form of 44PD with a quinone-diimine structure), 44PDOH (N-1,4 dimethylpentyl-p-phenol) and 1,4-dimethylpentylamine. Secondary hydrolysis products are p-hydroquinone and p-benzoquinone. The final hydrolysis product is 1-methyl-propylamine (sec-butylamine).
Key value for chemical safety assessment
- Half-life for hydrolysis:
- 5.3 h
- at the temperature of:
- 20 °C
Additional information
As no full OECD 111 hydrolysis test at pH4,7 and 9 is available for 77PD, read-across to 44PD is performed. 44PD (CAS 101 -96 -2) is also a member of the PD family. Instead of two heptyl groups as for 77PD, 44PD contains two sec. butyl groups. Due to the chemical similarity hydrolysis behaviour is expected to also occur in a similar way. Most information can be taken from the prolonged test (14days), performed at pH7 at 20°C. The parent substance disappears completely within 24 hours. Primary metabolites 44 -QDI and 44PD-OH were observed as intermediates from day 1 to 3. Finally, p-hydroquinone and p-benzoquinone are formed as secondary metabolites. The respective amine (in case of 77PD: 1,4 -dimethylpentylamine) was also detected. After 14 days, p-benzoquinone has been transformed to p-benzoquinone which finally represents about 30% of the original molar concentration of the parent substance.
These results are in accordance with supporting data from Monsanto (1986) where a half life of 3.4h was found. In this study, p-hydroquinone had disappeared after 5 days.
Further information about hydrolytical pathway and supporting information from other PPDs is given in the read-across justification document attached to IUCLID chapter 13.
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