N-(3-(trimethoxysilyl)propyl)ethylenediamine

Henry's Law constant

Link to relevant study record(s)

Reference

Endpoint:

Henry's law constant

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, but not (completely) falling into its applicability domain, with adequate and reliable documentation / justification

Principles of method if other than guideline:

The result was obtained using an appropriate QSAR method (see attached QMRF and QPRF for details).

The model is Bond Contribution Method within the publicly available HenryWin v 3.20 program (USEPA 2011). The Henry’s Law Constant (HLC) is calculated based on chemical structure, as the sum of the bond contribution values for each chemical bond in the molecule. The bond contribution values were determined based on least-square regression analysis of measured HLCs for organic compounds. The authors of the QMRF have carried out additional validation and found the method to be applicable to organosilicon compounds.

USEPA 2011. HenryWin v. 3.20, US EPA. Estimation Programs Interface Suite™ (EPI Suite) for Microsoft® Windows, v 4.10. United States Environmental Protection Agency, Washington, DC, USA (2011). Available at http://www.epa.gov/tsca-screening-tools/download-epi-suitetm-estimation-program-interface-v411.

H:

0 dimensionless

Temp.:

25 °C

Atm. press.:

1 013 hPa

H:

0 Pa m³/mol

Temp.:

25 °C

Atm. press.:

1 013 hPa

Conclusions:

A Henry's Law Constant value of 1.5E-14 Pa-m3/mol at 25°C was obtained for the silanol hydrolysis product using a validated QSAR estimation method. The result does not completely fall within the applicability domain but the prediction is reliable enough to show that the HLC is low. This result is considered to be reliable.

Description of key information

Henry's Law Constant:

 

For parent substance: Volatilisation from water is not relevant for the parent substance due to its very rapid hydrolysis in contact with water.

 

For silanol hydrolysis product : 1.5E-14 Pa m³mol^-1 at 25°C (calculated)

 

For methanol: 0.461 Pa m³mol^-1 at 25°C

Additional information

The transfer of a substance from the water phase to the gas phase can be estimated by means of the Henry’s Law Constant (HLC). No measured value for this parameter is available for the substance, due to rapid hydrolysis.

 

For the silanol hydrolysis product, N-(3-(trihydroxysilyl)propyl)ethylenediamine, the predicted water solubility limit cannot be validated accurately due to condensation phenomena. The HLC can be estimated using the established Bond method from HENRYWIN v. 3.20 within the EPIWeb suite v4.11. This method derives the Henry's Law Constant directly from the structure, as the sum of the bond contribution values for each chemical bond in the molecule. The bond contribution values were determined based on least-square regression analysis of measured HLCs for organic compounds.

 

The calculated HLC value for the silanol hydrolysis product at 25°C is very low, 1.5E-14 Pa m³mol^-1 (HenryWin v 3.20).

 

Methanol has a reported HLC value of 0.461 Pa m³mol^-1 at 25°C (OECD 2004).

 

 

 

References:

OECD (2004): SIDS Initial Assessment Report for SIAM 19, Berlin, Germany, 18-20 October 2004, Methanol, CAS 67-56-1