Registration Dossier

Physical & Chemical properties

Partition coefficient

Currently viewing:

Administrative data

Link to relevant study record(s)

Referenceopen allclose all

Endpoint:
partition coefficient
Data waiving:
study technically not feasible
Justification for data waiving:
the study does not need to be conducted because the substance decomposes
Endpoint:
partition coefficient
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
weight of evidence
Justification for type of information:
Because the test item undergoes rapid hydrolysis in contact with water, an experimental determination of logPow is technically not feasible. Thus, logPow evaluation of hydrolysis products is performed.
Reason / purpose:
read-across source
Reason / purpose:
read-across source
Key result
Type:
log Pow
Partition coefficient:
0.99
Temp.:
23 °C
Remarks on result:
other: pH value not specified
Key result
Type:
log Pow
Partition coefficient:
1.36
Temp.:
25 °C
pH:
6.68
Conclusions:
Partition coefficients of both hydrolsis product were determined to be 0.99 and 1.36 at 25 °C, respectively.
Executive summary:

Because the test item undergoes rapid hydrolysis in contact with water, an experimental determination of logPow is technically not feasible. Thus, logPow evaluation of hydrolsis products is performed.

In a study according to Regulation (EC) 440/2008 Part A A.8, using the shake flask method, the log Pow of 3 -(aminomethyl)-3,5,5 -trimethylcyclohexan-1 -amine (Isophorone diamine) was determined to be 0.99 at 23 °C.

Partition coefficient of 2,2-dimethyl-3-oxopropyl acetate (Aldehyde A) was determined as 1.36 ± 0.005 using HPLC method according to EU Method A.8, OECD 117, and OPPTS 830.7570.

Description of key information

The substance hydrolyses fast in contact with water, thus it was technically not feasible to perform the study. Instead a read across-approach to log Pow of the hydrolysis products was applied. The logPow of the resulting aldehyde was determined to be 1.36 at 25 °C and was regarded as worst case assumption for chemical safety assessment.

 

Key value for chemical safety assessment

Log Kow (Log Pow):
1.36
at the temperature of:
25 °C

Additional information

General considerations

In accordance with column 2 adaptation statement of Annex VII Regulation (EC) No 1907/2006 (REACH), the determination of the partition coefficient (as required in section 7.8 of Annex VII) the study does not need to be conducted as the substance decomposes during the performance of the test.

The hydrolysis rate of the test substance at pH = 4, 6, 7 and 9 (at room temperature) was investigated using FIMS (Flow Injection Mass Spectrometry) (please refer to IUCLUD section 5.1.2. Short- and long-term measurements show that the test substance hydrolysed faster at pH 4, 6 and 7 than at pH 9. FIMS data showed that at pH = 7 after 2 minutes only a weak signal of the test substance could be detected. Thus the hydrolysis half-live at pH = 7 was considered to be < 2 minutes.

Thus, it can be assumed that during the sample preparation for the OCED TG 107, 117 or 123 the substance will be completely hydrolysed before analytical measurement. Therefore, it was concluded that the performance of the study is technically not feasible.

The hydrolysis products of the substance were identified during the hydrolysis study. The substance hydrolysis forming 3-(aminomethyl)-3,5,5-trimethylcyclohexan-1-amine (Isophorone diamine) and 2,2-dimethyl-3-oxopropyl acetate (Aldehyde A).

The experimental determination of logPow of the test item was replaced by an appropriate calculation method and, in addition, a read across-approach to both hydrolysis products was applied.

 

Log Pow of the uncharged molecule of the test item

Using EpiSuite the log Pow of the uncharged molecule was calculated to be 7.159 at 25 °C. The substance is not within the applicability domain of the model. The substance has a functional group not represented in the training set, and for which no fragment coefficient was developed. Instead an estimated coefficient was used. Therefore the estimation may be less accurate.

 

LogPow of the hydrolysis products

3-(aminomethyl)-3,5,5-trimethylcyclohexan-1-amine (Isophorone diamine)

A study was conducted according to Regulation (EC) 440/2008 Part A A.8 to determine the logPow of the second hydrolysis product of the test item. Using the shake flask method the log Pow was determined to be 0.99 at 23 °C.

Using EpiSuite the log Pow of the uncharged molecule was calculated to be 1.90 at 25 °C. The substance is within the applicability domain of the model. Thus, the calculation was regarded as reliable.

 

2,2-dimethyl-3-oxopropyl acetate (Aldehyde A)

Partition coefficient of 2,2-dimethyl-3-oxopropyl acetate (Aldehyde A) was determined as 1.36 ± 0.005 at 25 °C using HPLC method according to EU Method A.8, OECD 117, and OPPTS 830.7570.

Using EpiSuite the log Pow of the uncharged molecule was calculated to be 0.7369 at 25 °C. The substance is within the applicability domain of the model. Thus, the calculation was regarded as reliable.

 

Conclusion

It was shown that the substance undergoes fast hydrolysis at environmental conditions. Thus, for chemical safety assessment the logPow of the hydrolysis products were taken into account. The log Pow of the two hydrolysis products were determined to be 0.99 and 1.36 at 25 °C. The logPow of 1.36 was regarded as worst case assumption and was therefore chosen as key value.