Registration Dossier

Administrative data

Endpoint:
Henry's law constant
Type of information:
(Q)SAR
Adequacy of study:
other information
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: QSAR calculated endpoint, considered reliable and suitable for assessment
Justification for type of information:
EPI Suite has undergone detailed review by a panel of EPA’s independent Science Advisory Board (SAB) (http://www.epa.gov/sab/).

Data source

Reference
Reference Type:
publication
Title:
HENRYWIN V 3.2 USEPA QSAR
Author:
Meylan and Howard
Year:
1991
Bibliographic source:
US EPA

Materials and methods

Test guideline
Qualifier:
no guideline followed
Principles of method if other than guideline:
HENRYWIN estimates Henry's Law Constant (HLC) by two separate methods that yield two separate estimates.  The first method is the Bond Contribution Method and the second is the Group Contribution Method. The Bond Method is able to estimate many more types of  structures than the Group Method because it has a more extensive library of bond contribution values.

 

HENRYWIN requires only a chemical structure to make these predictions.  Structures are entered into HENRYWIN by SMILES (Simplified Molecular Input Line Entry System) notations.  The six methods of entering a SMILES are listed in the Entering Data-SMILES section.

 

The following abstract from the Meylan and Howard (1991) article briefly summarizes the bond methodology:  

"Bond contribution values, used to estimate Henry's law constant (HLC)(air-to-water partition coefficient) from chemical structure, have been determined for 59 chemical bonds by a least-square analysis of HLCs for 345 organic compounds.  A correlation coefficient (r2) of 0.94 was determined for the relationship between known LWAPCs (log water-to-air partition coefficients) and bond estimated LWAPCs for the 345 compound data set.  The correlation increases to 0.97 when quantified correction factors are applied to selected chemical classes.  The ability of the bond method to estimate LWAPCs is demonstrated by a validation test set of 74 diverse and structurally complex compounds that were not included in the least-square analysis.  The correlation coefficient for the validation set is 0.96."  (Note: the bond value and correction factor list has been expanded significantly since the journal article was published).
GLP compliance:
not specified

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
Not applicable

Results and discussion

Henry's Law constant H
H:
0.491 Pa m³/mol
Temp.:
25 °C
Remarks on result:
other: Based on bond estimation method

Applicant's summary and conclusion

Conclusions:
The Henry's law constant of sulfolane is calculated to be 0.491 Pa m3/mol
Executive summary:

The Henry's law constant of sulfolane was estimated to be 0.491 Pa m3/mol using the US EPA QSAR, HENRYWIN v3.2. The QSAR calculation was based on the bond estimation method. This method is considered appropriate for assessment of this endpoint.