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Environmental fate & pathways

Henry's Law constant

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Description of key information

From the water surface, MCHAmix (EC 943 -517 -5) will slowly evaporate into the atmosphere.

Key value for chemical safety assessment

Henry's law constant (H) (in Pa m³/mol):
1.85
at the temperature of:
25 °C

Additional information

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 Reaction product of 2,4-Dinitrotoluene and 2,6-Dinitrotoluene and hydrogen, deaminated (MCHAmix EC 943 -517 -5) (Q)SAR results were used for the estimation of the Henry’s Law constant. 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 Henry’s Law Constant are not provided.

 

Assessment

The Henry's Law constant was calculated for 2-Methylcyclohexylamine (CAS 7003-32-9) and 4-Methylcyclohexylamine (CAS 6321-23-9) which are representative constituents of the reaction product of 2,4-Dinitrotoluene and 2,6-Dinitrotoluene and hydrogen, mono-demethylated (MCHAmix, EC 939-489-9).

The bond estimation method of HENRYWIN v3.20 of EPI Suite v4.11 does not differentiate between the two representative constituents (CAS 7003-32-1 and CAS 6321-23-9); therefore, the calculation results for both substances are identical.

The bond estimation method gives a value of 1.85 Pa*m³/mol for both constituents (HENRYWIN v3.20; BASF SE 2016). These estimates refer to the uncharged molecule. The substances are within the applicability domain of the model.

It can be concluded that based on the read-across approach, MCHAmix (EC 943-517-5) will slowly evaporate from the water surface into the atmosphere.

At environmentally relevant conditions, the substances are expected to be ionised based on the calculated dissociation constants for the two substances (pka = 10.38 to 10.39, SPARC On-Line Calculator, see IUCLID Ch. 4.21); therefore, the model results may overestimate the evaporation potential of the substance.