dimethyl 1,2-benzenedicarboxylate;reaction mass of: 1,2-dimethylpropylidene dihydroperoxide

Adsorption / desorption

Link to relevant study record(s)

Reference

Endpoint:

adsorption / desorption, other

Remarks:

(Q)SAR

Type of information:

(Q)SAR

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: A calculated value using QSAR's is given.

Justification for type of information:

QSAR prediction

Qualifier:

equivalent or similar to guideline

Guideline:

other: The adsorption/desorption has been calculated using the method described in the Technical Guidance Document on Risk Assessment (1996).

Computational methods:

Calculation of Adsorption/Desorption.
The adsorption/desorption of MIPKP has been calculated using the method described in the Technical Guidance Document on Risk Assessment (1996).

Physical Chemical Data:
- Boiling temperature: Reaction or decomposition of the test substance was observed above 80°C. Boiling of the test substance was not observed
below the temperature at which reaction or decomposition started.
- Density: 1.16 g/cm3 (20.0 ± 0.5°C).
- Vapour pressure: 761 ± 30 Pa Pa (20°C).
- Surface tension: 52.6 mN/m (20 ± 0.5°C);
- Water solubility: Test temperature: 20.0 ± 0.4°C at pH 3.5. During the test MIPK is formed as a result of the reaction of the other peroxidic compounds with water. Based on MIPK, the water solubility of Trigonox R-938 was determined to be >= 230 g/l. Based on MIPKP-T4, the water solubility of Trigonox R-938 was estimated to be >= 201 g/l. Based on MIPKP-T3 peak 1, the water solubility of Trigonox R-938 was determined to be 2.53 g/l. Based on MIPKP-T3 peak 2, the water solubility of Trigonox R-938 was determined to be 1.73 g/l.
The water solubility of DMP is given in the literature as 4000 ± 60 mg/l at 25°C.
- Partition coefficient: The results of the Estimation method and the Flaskshaking method were not in agreement. Results using the HPLC method: The Pow value for the major component in Trigonox R-938 is 3.60 x 10^1 (log Pow = 1.6) at 24.5 ± 1.0°C.
The Pow values for five minor components in Trigonox R-938 are 1.84, 7.06, 1.36 x 10^2, 1.65 x 10^3 and 2.47 x 10^3 (log Pow values of 0.27, 0.85,
2.1, 3.2 and 3.4) at 24.5 ± 1.0°C.

The adsorption/desorption of MIPKP is based on the major component DMP and the minor component MIPKP-T3 (consists of two isomers). The other components, including the main peroxidic component MIPKP-T4 have much higher water solubilities and correspondingly lower log Pow's and are therefore of lesser concern.

Key result

Type:

log Koc

Value:

>= 2.2 - <= 2.3 dimensionless

pH:

7

Temp.:

25 °C

Remarks on result:

other: MIPKP Type 3, two isomers

Details on results (HPLC method):

Several chemical classes can be used:
Non Hydrophobics (I) and esters (II) having different QSAR's and a log Po/w of 1.6 (major component) has been used:

(I) Log Koc = 0.52 log Po/w + 1.02 = 1.85
(II) Log Koc = 0.49 log Po/w + 1.05 = 1.83

Mean Log Koc = 1.8 (range 1.83 - 1.85, based on the Log Kow of DMP).

Non Hydrophobics (I) and alcohols (II) having different QSAR's and a log Po/w of 3.2 and 3.4 (Isomers of the minor component) has been used:

(I) Log Koc = 0.52 log Po/w + 1.02 = 2.68 (log Pow=3.2)
(I) Log Koc = 0.52 log Po/w + 1.02 = 2.79 (log Pow=3.4)
(II) Log Koc = 0.39 log Po/w + 0.50 = 1.75 (log Pow=3.2)
(II) Log Koc = 0.39 log Po/w + 0.50 = 1.83 (log pow=3.4)
Mean Log Koc = 2.21 (range 1.75 -2.68, based on the Log Kow = 3.2 of MIPKP-T3).
Mean Log Koc = 2.31 (range 1.83 -2.79, based on the Log Kow = 3.4 of MIPKP-T3).

Validity criteria fulfilled:

not applicable

Conclusions:

The different QSAR's give different outcomes of the Log Koc. For risk assessment purposes in the European Economic Area, these calculated values should be used, in view of all uncertainties using QSAR.
For the main component DMP: Log Koc=1.84.
For the minor component MIPKP-T3 based on the two isomers: Log Koc=2.2 and Log Koc=2.3.

Executive summary:

The different QSAR's give different outcomes of the Log Koc. For risk assessment purposes in the European Economic Area, these calculated values should be used, in view of all uncertainties using QSAR.

For the main component DMP: Log Koc=1.84.

For the minor component MIPKP-T3 based on the two isomers: Log Koc=2.2 and Log Koc=2.3.

Description of key information

For MIPKP-T3 based on the two isomers: Log Koc=2.2 and Log Koc=2.3.

Key value for chemical safety assessment

Koc at 20 °C:

200