Hexamethylene diisocyanate

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

calculation (if not (Q)SAR)

Remarks:

Migrated phrase: estimated by calculation

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Accepted calculation method

Principles of method if other than guideline:

A "fragment constant" methodology is used to predict log P. For this, a structure is divided into fragments (atom or larger functional groups) and coefficient values of each fragment or group are summed together to yield the log KOW estimate.

GLP compliance:

no

Type of method:

calculation method (fragments)

Partition coefficient type:

octanol-water

Type:

log Pow

Partition coefficient:

3.2

Remarks on result:

other: pH and termperature not specified in the QPRF

Details on results:

- calculated

Temperature and pH are not specified. Any decomposition of the substance in water (e.g. due to hydrolysis, photolysis) is not taken into account by the program.

Algorithm (OECD Principle 2)

c.       Model or submodel name:

Individual model KOWWIN included in the Estimation Programs Interface (EPI) Suite.

d.       Model version:

KOWWIN v1.68 included in EPI-Suite v 4.11, ©2000 - 2012

e.       Reference to QMRF:

“QSAR Model Reporting Format (QMRF) for log Kow estimation”, Currenta GmbH & Co. OHG, 2011-05-19.

f.       Predicted value (model result):

log Kow = 3.20

g.       Predicted value (comments):

No information available.

h.       Input for prediction:

A CAS number was entered in the initial data entry screen. In the structure window, the molecular weight, structural formula and the structure of the input SMILES notation is shown.

i.       Descriptor values:

The molecule is separated into distinct atom/fragments using an Atom/Fragment Contribution method. Based on structure of the molecule, various steric interactions, hydrogen-bondings, and effects from polar functional substructures were identified and individual correction factors were selected through a tedious process of correlating the differences (between log Kow estimates from atom/fragments alone and measured log Kow values) with common substructures.

For HDI the following fragment descriptors were applied:

Type	NUM	Fragment	Fragment Description
FRAG	6	-CH	[aliphatic carbon]
FRAG	2	-N=C=O	[isocyanate, aliphatic attach]

Executive summary:

The calculated log Pow of 1,6 -Hexamethylene diisocyanate (HDI) is 3.20. But the result should only be considered of theoretical interest since the calculation program is adequate for substances which show stability in water (Currenta, 2009).

Description of key information

In accordance with column 2 of REACH Annex VII, the test cannot be performed, as the substance decomposes in water. 
Calculated with Epiwin:                               3.2
0.02 (hydrolysis product of HDI,1,6-hexane diamine)   0.02

Key value for chemical safety assessment

Log Kow (Log Pow):

3.2

at the temperature of:

20 °C