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Henry's Law constant

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Description of key information

Henry's law constants for the main components of the reaction products of 1-decene, 1-dodecene, 1-octene, hydrogenated have been estimated using the US EPA EPI Suite (v3.12) computer program to assess volatilization from water.  The calculated Henry’s law constant values of 23.7 to 47.6 atm-m3/mole for the main C20-C22 components (comprising at least 85% of the registered substance) indicate minimal volatilization to air from the aqueous environment.  In addition, calculated vapor pressure values for the registered substance (range: 0.611 to 0.00313 Pa at 25 C) also support limited volatilization from the terrestrial compartment (e.g., soil).  

Key value for chemical safety assessment

Additional information

The C18 to C24 components in the registered substance have calculated vapor pressure ranging from 0.6110 to 0.00313 Pa at 25 °C, which indicate relatively low volatility and limited volatilization in the terrestrial compartment. In addition, the Henry’s law constants for the C20-22 main components of the registered substance have been calculated to be 23.7 to 47.6 atm-m3/mole using the US EPA EpiSuite(v3.12) program(US EPA 2000) and they indicate that volatilization from water, if it occurs, is relatively slow. Based on the calculated vapor pressure and the Henry's law constants data, the main components in the registered substance most likely volatilize slowly to air from aqueous environments and also have limited volatilization from soil.

 

EpiSuite (v3.12) (US EPA 2000) estimated the following Henry’s law constants (in atm-m3/mole) for the various C18-C24 PAO components in the registered substances:

C18 H38 11.9-16.3 atm-m3/mole

C20H42  23.7-41.7  

C22H46  47.6  

C24H50  98.0

Registrant's comments:

The US EPA EPI-Suite modeling program has been extensively used in the OECD SIDS and the US EPA High Production Volume (HPV) programs and more importantly, the US EPI-Suite program is an integrated predictive tool in the OECD Toolbox to calculate physico-chemical and environmental fate properties for chemicals. Hence, the need to supply QMRF and QPRF for commonly applied EPI-Suite models is not warranted given its already accepted use in global regulatory notifications and its integration and underpinning in the OECD Toolbox for REACH