Registration Dossier

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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

Diss Factsheets

Administrative data

basic toxicokinetics in vitro / ex vivo
Adequacy of study:
supporting study
other: Expert statement is attached.
Rationale for reliability incl. deficiencies:
other: No studies are available on the toxicokinetics, metabolism and distribution of dihexadecyl peroxodicarbonate. Predictions were made based on physical-chemical properties and information from tox. studies.

Data source

Materials and methods

Test material

Constituent 1
Chemical structure
Reference substance name:
1,1,3,3-tetramethylbutyl peroxyneodecanoate
EC Number:
EC Name:
1,1,3,3-tetramethylbutyl peroxyneodecanoate
Cas Number:
Molecular formula:
2,4,4-trimethylpentan-2-yl 2,2,3,5-tetramethylhexaneperoxoate; 2,4,4-trimethylpentan-2-yl 2,2-diethylhexaneperoxoate; 2,4,4-trimethylpentan-2-yl 2,2-dimethyloctaneperoxoate; 2,4,4-trimethylpentan-2-yl 2,4-dimethyl-2-(propan-2-yl)pentaneperoxoate; 2,4,4-trimethylpentan-2-yl 2-ethyl-2,5-dimethylhexaneperoxoate

Results and discussion

Applicant's summary and conclusion

While toxicokinetic data is not available on 1,1,3,3-tetramethylbutyl peroxyneodecanoate, if absorbed, it is expected to be rapidly converted to multiple breakdown products and 1,1,3,3-tetramethylbutyl peroxyneodecanoate is not expected to bioaccumulate.
Executive summary:

1,1,3,3-tetramethylbutyl peroxyneodecanoate is unstable with a hydrolysis half life less than 24 hours at 15°C (OECD111).The pure peroxide is not commercially available and always used in closed systems. Due to its instability, a phlegmatizer is added. Therefore the commercial product is always a mixture of peroxide and phlegmatizer.  

Multiple breakdown products were identified (Datta, 2012). The breakdown products were not quantified. 1,1,3,3-tetramethylbutyl peroxyneodecanoate is converted to TMBH hydroperoxide (CAS#5809-08-5) which is broken down to neopentyl alcohol (CAS#75-84-3)Other breakdown products are 2,2,4-trimethylpentanol-2 (CAS# 123-44-4) and acetone (CAS# 67-64-1). 

The available physico-chemical and toxicological information of the substance has been evaluated and used to assess the toxicological behaviour. The results of this analysis will address the question on how the chemical will react in the body.

Dermal Absorption

Based on the log Pow of 6.9, the peroxide is expected to stay partitioned in the phlegmatizer. Based on the log Pow of 6.96, vapor pressure and water solubility, the phlegmatizer is not expected to penetrate the skin to a significant degree. Therefore, the peroxide would not be expected to be significantly absorbed either. The substance is mildly irritating to skin and increased absorption due to damaged skin is therefore not very likely. 

If absorbed however, the peroxide would quickly undergo thermal decomposition to multiple breakdown products at body temperature.


Inhalation Absorption

The measured vapor pressure of the peroxide isododecane mixture was <0.24 Pa at 25°Cand of the peroxide 0.0001-0.01Pa. Based on the low vapor pressure and pattern of use, inhalation is not expected to be a major route of exposure. If inhalation of the peroxide does occur, as stated above it will rapidly decompose to multiple breakdown products.


Oral Absorption

In repeated oral gavage studies with the peroxide (70%) in phlegmatizer, findings were noted in kidneys of male rats (alpha-2μ-globulin) and livers of male and female rats (higher mean liver weight and hepatocellular hypertrophy). The liver effects were considered adaptive and the alpha-2μ-globulin is specific to the male rat with no human relevance. 


In a 90-day oral gavage study reported in the REACH disseminated dossier, the phlegmatizer was administered to rats at 500, 2500 and 5000 mg/kg/day. Similar liver findings were reported at 2500 and 5000 mg/kg/day and similar kidney effects in all dose groups. 


While it is not possible to establish the causative agent of the findings noted in the 28-day study with the product (i.e. the solvent or peroxide), the peroxide is expected to quickly decompose to multiple breakdown products at body temperature .



While toxicokinetic data is not available on 1,1,3,3-tetramethylbutyl peroxyneodecanoate, if absorbed, it is expected to be rapidly converted to multiple breakdown products. 1,1,3,3-tetramethylbutyl peroxyneodecanoate is not expected to bioaccumulate.