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Diss Factsheets

Physical & Chemical properties

Partition coefficient

Currently viewing:

Administrative data

Endpoint:
partition coefficient
Type of information:
(Q)SAR
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
results derived from a valid (Q)SAR model and falling into its applicability domain, with limited documentation / justification

Data source

Referenceopen allclose all

Reference Type:
other: EPIWIN calculation
Title:
Unnamed
Year:
2018
Report date:
2018
Reference Type:
other: Estimation software
Title:
Estimation Programs Interface Suite for Microsoft Windows, v4.11
Author:
US-EPA
Year:
2012
Bibliographic source:
United States Environmental Protection Agency, Washington, DC, USA

Materials and methods

Test guideline
Qualifier:
no guideline required
Principles of method if other than guideline:
Estimation of log Kow using KOWWIN v1.68
GLP compliance:
no
Type of method:
other: estimation method
Partition coefficient type:
octanol-water

Test material

Constituent 1
Chemical structure
Reference substance name:
2,2'-dimethyl-2,2'-azodipropiononitrile
EC Number:
201-132-3
EC Name:
2,2'-dimethyl-2,2'-azodipropiononitrile
Cas Number:
78-67-1
Molecular formula:
C8H12N4
IUPAC Name:
2,2'-dimethyl-2,2'-azodipropiononitrile
Test material form:
solid: particulate/powder

Results and discussion

Partition coefficient
Type:
log Pow
Partition coefficient:
2.87
Temp.:
25 °C
Remarks on result:
other: The substance is within the applicability domain of the model.

Any other information on results incl. tables

-------+------+--------------------------------------------------+----------+--------

TYPE | NUM | LOGKOW FRAGMENT DESCRIPTION | COEFF | VALUE

-------+------+--------------------------------------------------+----------+--------

Frag | 4 | -CH3 [aliphatic carbon] | 0.5473 | 2.1892

Frag | 2 | C [aliphatic carbon - No H, not tert] | 0.9723 | 1.9446

Frag | 2 | -C#N [cyano, aliphatic attach] |-0.9218 | -1.8436

Frag | 1 | -N=N- [Azo] | 0.3541 | 0.3541

Const| | Equation Constant | | 0.2290

-------+------+--------------------------------------------------+----------+--------

Log Kow = 2.8733

Applicant's summary and conclusion

Executive summary:

QPRF: KOWWIN v1.68 (01 Nov. 2013)

 

1.

Substance

See “Test material identity”

2.

General information

 

2.1

Date of QPRF

See “Data Source (Reference)”

2.2

QPRF author and contact details

See “Data Source (Reference)”

3.

Prediction

3.1

Endpoint
(OECD Principle 1)

Endpoint

Octanol-water partition coefficient (log Kow)

Dependent variable

Octanol-water partition coefficient (log Kow)

3.2

Algorithm
(OECD Principle 2)

Model or submodel name

KOWWIN

Model version

v. 1.68

Reference to QMRF

QMRF: Estimation of Octanol-Water Partition Coefficient using KOWWIN v1.68 (EPI Suite v4.11)

Predicted value (model result)

See “Results and discussion”

Input for prediction

Chemical structure via CAS number or SMILES

Descriptor values

- Chemical structure

- Fragments

- Correction factors

3.3

Applicability domain
(OECD principle 3)

Domains:

1) Molecular weight
(range of test data set: 18.02 to 719.92 g/mol; On-Line KOWWIN User’s Guide, Ch. 6.2.3 Estimation Domain)

Substance within range (164.21 g/mol)

2) Fragments: Number of instances of the identified fragments does not exceed the maximum number as listed in Appendix D (On-Line KOWWIN User’s Guide)

fulfilled.

3) Fragments: Substance has a functional group(s) or other structural features not represented in the training set, and for which no fragment coefficient was developed (Appendix D, On-Line KOWWIN User’s Guide)

Not applicable.

4) Correction factors: Number of instances of the identified correction factor does not exceed the maximum number as listed in Appendix D (On-Line KOWWIN User’s Guide)

Not applicable as no correction factors were used.

 

fulfilled.

 

3.4

The uncertainty of the prediction
(OECD principle 4)

According to REACH Guidance Document R.7a, (Nov. 2012), solubility in water is difficult to model accurately. For this reason, as well as the fact that the experimental error on solubility measurements can be quite high (generally reckoned to be about 0.5 log unit), the prediction of aqueous solubility is not as accurate as is the prediction of octanol/water partitioning.

3.5

The chemical mechanisms according to the model underpinning the predicted result
(OECD principle 5)

The water solubility of a substance depends on its affinity for water as well as its affinity for its own crystal structure. In general, substances with high melting points have poor solubility in any solvent.

 

References

- US EPA (2012). On-Line KOWWIN User’s Guide.