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Environmental fate & pathways

Henry's Law constant

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Administrative data

Endpoint:
Henry's law constant
Type of information:
experimental study
Adequacy of study:
supporting study
Study period:
Not reported
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Study conducted in accordance with generally accepted scientific principles, possibly with incomplete reporting or methodological deficiencies, which do not affect the quality of the relevant results.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1987
Report Date:
1987

Materials and methods

Test guideline
Qualifier:
no guideline available
Principles of method if other than guideline:
The experimental technique used was similar to the one used by Mackay, et al.* for determining the air-water Henry's law constant for hydrophobic compounds. Good laboratory practices were followed throughout the determination.

* Donald Mackay, Wan Ying Shiu, and Russell P. Sutherland, Environmental Science & Technology, 13(3), 333-337 (1979).
GLP compliance:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
The material used was cis-1,3-dichloropropene (AGR 164300) which was provided by Eric Martin of the Agricultural Products Department. The purity of AGR 164300 has been determined several times previously and is nominally 94.8%, with the major impurity being the close-boiling trans-1,3-dichloropropene.

Results and discussion

Henry's Law constant H
H:
0.002 atm m³/mol
Temp.:
25 °C
Atm. press.:
34.3 mm Hg

Any other information on results incl. tables

To test our technique we conducted experiments with toluene at two different flowrates. The average value of the Henry's law constant for toluene, 6.25 x l0-3 m3 atm/gmol at 25 ºC, determined in this study was in good agreement with the value of 6.64 x 10-3 m3 atm/gmol obtained by Mackay et al. Air-water Henry's constant values for cis-1,3-dichloropropene were found to be 1.93 x 10-3 and 1.72 x 10-3m3 atm/gmol for the two flow rates respectively. The average value is 1.8 x 10-3 m3 atm/gmol.

It is possible to calculate a value of Henry's law constant for compounds which are slightly soluble in water, from the ratio of their vapor pressure Pi to their water solubility Si, Hi = Pi/Si. For cis-1,3-dichloropropene at 25 ºC the vapor pressure is 34.3 mmHg (0.0451 atm) and the water solubility is 2180 ppm (19.64 gmol/m3). The calculculated Henry's law constant at 25 ºC is therefore 2.29 x 10-3 m atm/gmol. The agreement with the directly measured value is satisfactory. The measured value of 1.8 x 10-3 m3 atm/gmol is preferred since the water solubility of cis-l,3-dichloropropene is high enough that the calculated value is only approximately correct.

It is possible to calculate a value of Henry's law constant for compounds which are slightly soluble in water, from the ratio of their vapour pressure Pi to their water solubility Si, Hi = Pi/Si. For cis-1,3-dichloropropene at 25 ºC the vapour pressure is 34.3 mmHg (0.0451 atm) and the water solubility is 2180 ppm (19.64 gmol/m3). The calculated Henry's law constant at 25 ºC is therefore 2.29 x 10-3 m3 atm/gmol. The agreement with the directly measured value is satisfactory. The measured value of 1.8 x 10-3 m3 atm/gmol is preferred since the water solubility of cis-l,3-dichloropropene is high enough that the calculated value is only approximately correct.

Applicant's summary and conclusion

Conclusions:
Air-water Henry's law constant for cis-1,3-dichloropropene was found to be 1.8 x 10-3 m3 atm/gmol at 25 °C.
Executive summary:

The experimental technique used was similar to the one used by Mackay, et al.for determining the air-water Henry's law constant for hydrophobic compounds. Good laboratory practices were followed throughout the determination.

Air-water Henry's law constant for cis-1,3-dichloropropene was found to be 1.8 x 10-3 m3 atm/gmol at 25 °C.