Nitriles, C16-18 and C18-unsatd.

Adsorption / desorption

Link to relevant study record(s)

Reference

Endpoint:

adsorption / desorption: screening

Type of information:

(Q)SAR

Adequacy of study:

key study

Study period:

2023

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 adequate and reliable documentation / justification

Justification for type of information:

1. SOFTWARE
EPI Suite v4.11

2. MODEL (incl. version number)
KOCWIN v2.00

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL

Only constituents that are present at ≥2% w/w were considered in the fragment-based calculations.

Tetradecanenitrile,
CAS no.: 629-63-0
SMILES: CCCCCCCCCCCCCC#N

Hexadecanenitrile
CAS no.: 629-79-8
SMILES: CCCCCCCCCCCCCCCC#N

Octadecanenitrile
CAS no.: 638-65-3
SMILES: CCCCCCCCCCCCCCCCCC#N

(Z)-Octadec-9-enenitrile
CAS no.: 112-91-4
SMILES: CCCCCCCCC=CCCCCCCCC#N

Alkylnitrile Content MCI KOC Kow KOC MCI contribution to weighted average Kow contribution to weighted average
14 3.8 6268 31460 238 1195
16 35.3 20820 109600 7349 38689
18 16.9 69140 381900 11685 64541
18' 39.5 69140 292200 27310 115419
Weighted average KOC Tallownitrile (L/kg) 46583 219844




4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
- Defined endpoint: Log Koc (organic carbon/water partition coefficient)
- Unambiguous algorithm: see the method description attached
- Defined domain of applicability: see the method description attached
- Appropriate measures of goodness-of-fit and robustness and predictivity: see the method description attached
- Mechanistic interpretation: see the method description attached
The Log Koc values selected for the KOCWIN training and validation datasets are available via: http://esc.syrres.com/interkow/EpiSuiteData.htm


5. APPLICABILITY DOMAIN
- Model domain: Currently there is no universally accepted definition of model domain. However, users may wish to consider the possibility that Organic carbon/water partition coefficient estimates are less accurate for compounds outside the MW and log Kow ranges of the training set compounds, and/or that have more instances of a given correction factor than the maximum for all training set compounds. In general, the intended application domain for all models embedded in EPISuite is organic chemicals.
The log Koc values range from 4.67 to 5.34. As there is currently preference of either method applied as both used specific nitrile correction factors. The mean Koc value of 133212 L/kg will be used for the EPM and risk assessment purposes.

- Mechanistic domain:
The KOCWIN MCI method calculates the Koc based on fragment constants and corects this Koc by applying corrction factor which are in this case specific for Nitrile/Cyanide (-C#N). The KOCWIN KOW method calculates the Koc based on this equation Log Koc (0.55313 logKow + 0.9251) and corrects this Koc value like for the MCI method using a specific correction factor for Nitrile/Cyanide (-C#N). This approach is applied to different types of organic compounds including acids and bases. No charged nitrogen compounds (nitrogen with a +5 valence such as quaternary ammonium compounds) can be calculated.

- Similarity with analogues in the training set:
Unknown

- Other considerations (as appropriate):

6. ADEQUACY OF THE RESULT
The calculated average value calculated for the main fragments of the substance shows that the substance is predicted to sorb strongly to organic carbon. The log Koc values range from 4.67 to 5.34. As there is currently no preference of either method applied as both used specific nitrile correction factors and the log Kow can reliably be determined for linear alkane nitriles. The mean Koc value of 133212 L/kg will be used for the EPM and risk assessment purposes.

Guideline:

other: REACH guidance on QSAR's R.6

Principles of method if other than guideline:

See attached documentation

GLP compliance:

no

Type of method:

other: QSAR

Media:

soil

Radiolabelling:

no

Sample No.:

#1

Phase system:

solids-water in soil

Remarks:

Modelled partitioning between the organic carbon fraction in soil and water (Koc)

Type:

other: The predicted organic carbon normalized equilibrium constant for partitioning between soil and water (Koc)

Value:

133 212 L/kg

Temp.:

21 °C

pH:

7

Matrix:

Organic carbon normalized partitioning coefficient considered to be independent of the matrix

Conclusions:

Amines, di-C16-18-alkylmethyl is predicted to sorb strongly to the organic carbon fraction in soil, sediment and sludge.

Executive summary:

No actual data are available for characterizing the partitioning to organic carbon in water (Koc) for Amines, di-C16-18-alkylmethyl . Modelled data are therefore considered to assess this parameter. The result obtained indicates that Amines, di-C16-18-alkylmethyl has an estimated Koc of > 1*10^6 L/kg calculated for its major constituents. On this basis it can be assumed that Amines, di-C16-18-alkylmethyl will not be mobile in soil and sediment.

Because the substance is also readily biodegradable the substance will either be sorbed or biodegraded.

Description of key information

No actual data are available for characterizing the sorption to soil or sediment organic carbon  of Amines, di-C16-18-alkylmethyl . Modelled data are therefore considered to assess this parameter. The result obtained indicates that Amines, di-C16-18-alkylmethyl has an estimated Log Koc of 9.35 to 9.69 L/kg calculated for its major constituents. On this basis it can be assumed that Amines, di-C16-18-alkylmethyl has a high sorption potential and will not be mobile in soil or sediment. 

This range is however outside the advised range from EUSES which suggests to limit the Koc to 1* 10^6 L/kg. This threshold value will therefore be used for risk assessment purposes.

Key value for chemical safety assessment

Koc at 20 °C:

1 000 000

Additional information

Amines, di-C16-18-alkylmethyl has an estimated Log Koc of 9.35 to 9.69 L/kg calculated for its major constituents. This range is however outside the advised range from EUSES which suggests to limit the Koc to 1* 10^6 L/kg. This threshold value will therefore be used for risk assessment purposes.