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Environmental fate & pathways

Henry's Law constant

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Description of key information

From the water surface, the substance will not evaporate into the atmosphere.

Key value for chemical safety assessment

Additional information

The Pigment Orasol Black X51 (EC no. 939-191-9) is a multipartite chromium complex composed of single complex fractions of azo compounds and amine compounds of the mixture Tridecanamine (TDA), branched and linear (CAS 86089-17-0).

 

TDA, branched and linear (CAS 86089-17-0) is a mixture of (predominantly) mono-alkyl amines with varying alkyl-chain length in a range between C10 and C14. The main fraction consists of C13 amines followed by the C12- , C11- and C14-amines. The following relative distribution of the C10 to C14 alkylamines was confirmed by GC/MS analysis:

•      C10-amines: 1% (selected as representative amine compound; reason: shortest alkyl chain)

•      C11-amines: 12%

•      C12-amines: 16%

•      C13-amines: 68% (selected as representative amine compound; reason: main component)

•      C14-amines: 3% (selected as representative amine compound; reason: longest alkyl chain)

 

EPI SuiteTM cannot be used for all chemical substances. The intended application domain is organic chemicals. Inorganic and organometallic chemicals generally are outside the domain. Therefore, there are no reliable estimated data for the organometallic component Orasol Black X51 (EC no. 939-191-9) available.

As EPI Suite is not capable of reliably estimating data for Orasol Black X51, the calculation was performed for the respective azo-dye components without metal complexation (CAS 6434-57-7 and CAS 14847-54-2) as well as for three representative amine compounds (C10, C13 and C14).

 

Calculation results for Orasol Black X51 (EC no. 939-191-9) as well as the selected representative azo- and amine components:

Substance

HENRYWIN v3.20

(EPI Suite v4.11)

referring to the uncharged molecule

pH-corrected HLC

at pH 7**

[Pa*m³/mol]

Azo-component

(CAS 6434-57-7)

6.21E-12

-

Azo-component

(CAS 6434-57-7)

C10-Amine component 

(CAS 2016-57-1)

9.83

(substance in AD)

0.00382

C13-Amine component

(CAS 2869-34-3)

23

(substance not in AD)

0.00894

C14-Amine component

(CAS 2016-42-4)

30.5

(substance not in AD)

0.0119

**NOTE: The estimated data for the pH-corrected HLC were calculated via an obsolete and calculation method; these data are only used in terms of a weight-of evidence approach.

 

Overall conclusion:

The estimated data indicate the amine compounds of Orasol Black X51 (EC 939-191-9) to slowly evaporate into the atmosphere; the highest calculation value available for the selected C14-Amine component tetradecylamine (CAS 2016-42-4) is considered as worst-case key value for the chemical safety assessment.

However, the complete complex of the target substance Orasol Black X51 is of an organometallic solid structure. Therefore, the vapour pressure is considered to be negligible (see IUCLID chapter 4.6). In addition, the substance has a very low water solubility (see IUCLID chapter 4.8). According to REACH guidance chapter R.7a (ECHA, 2014) the HLC can be relatively large if a substance has both, a low vapour pressure and low water solubility, and if calculated using the ratio of vapour pressure and water solubility. This might imply, that volatilisation is an important fate process. In practice, however, adsorption to dissolved organic carbon is likely to be much more relevant, and volatilisation will be lower than the estimated HLC value suggests.

In addition, pH is an important factor for compound (substance) classes that dissociate to a significant extent in water because only non-dissociated species undergo air-water exchange. For most natural waters (6 < pH < 8) the apparent HLC will, therefore, be significantly less than the intrinsic HLC (REACH guidance chapter R.7a (ECHA, 2014). Considering the available data on the dissociation constant (see IUCLID chapter 4.21), at least, the amine C10 to C14 components of Orasol Black X51 will dissociate in Water to significant extend (pKa = 10.41; SPARC on-Line calculator). 

In summary, the volatilisation of the substance from the compartment water into the atmosphere is considered to be negligible.  

 

QSAR-disclaimer

In Article 13 of Regulation (EC) No 1907/2006, it is laid down that information on intrinsic properties of substances may be generated by means other than tests, provided that the conditions set out in Annex XI (of the same Regulation) are met.

According to Annex XI of Regulation (EC) No 1907/2006 (Q)SAR results can be used if (1) the scientific validity of the (Q)SAR model has been established, (2) the substance falls within the applicability domain of the (Q)SAR model, (3) the results are adequate for the purpose of classification and labeling and/or risk assessment and (4) adequate and reliable documentation of the applied method is provided.

For the assessment of the Orasol Black X51 (EC no. 939-191-9) (Q)SAR results were used for the estimation of the HLC. The criteria listed in Annex XI of Regulation (EC) No 1907/2006 are considered to be adequately fulfilled and therefore the endpoint(s) sufficiently covered and suitable for risk assessment.

Therefore, further experimental studies on the adsorption potential are not provided.