mecoprop-P (ISO); (R)-2-(4-chloro-2-methylphenoxy)propionic acid

Henry's Law constant

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

Henry's law constant

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1994

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

no guideline followed

Principles of method if other than guideline:

The constant H of Henry's Law can be established experimentally for a specific compound or it can be determined from its vapor pressure and water solubility.
For a reliable calculation the miscibility of the substance with water should not exceed a few mole percent. If the water solubility is high or if the vapour pressure is very low, the result of the calculation is only valid for an orientation.
In the case of the test material both the vapour pressure and the water solubility are known. From these the Henry's Law Constant is calculated.

GLP compliance:

not specified

Key result

H:

0 Pa m³/mol

Temp.:

20 °C

Remarks on result:

other: Atmospheric pressure not specified

For the test material:

p = 4.0 x 10^-7 (kPa) at 20 °C

MW = 214.6 (g/mol)

c = 0.086 x 10^4 (g/m^3) at 20 °C

H = (4.0 x 10^-1 (kPa) ꞏ 214.6 g/mol) / (0.086 x10^4 g/m^3)

Henry’s Law Constant: H = 9.981 x 10^-8 (kPa m^3/mol)

Conclusions:

Under the conditions of the study the Henry’s Law Constant for the test material was calculated to be 9.981 x 10^-8 (kPa m^3/mol).

Executive summary:

The constant H of Henry's Law can be established experimentally for a specific compound or it can be determined from its vapour pressure and water solubility.

For a reliable calculation the miscibility of the substance with water should not exceed a few mole percent. If the water solubility is high or if the vapour pressure is very low, the result of the calculation is only valid for an orientation.

In the case of the test material both the vapour pressure and the water solubility are known. From these the Henry's Law Constant is calculated.

Under the conditions of the study the Henry’s Law Constant for the test material was calculated to be 9.981 x 10^-8 (kPa m^3/mol).

Reference 2

Endpoint:

Henry's law constant

Type of information:

experimental study

Adequacy of study:

key study

Study period:

02 February 1999 to 22 June 1999

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Henry’s Law constant for the test material was estimated from the vapour pressure and water solubility data in a guideline physico-chemical properties report.

Principles of method if other than guideline:

Henry’s Law constant for the test material was estimated from the vapour pressure and water solubility data in a guideline physico-chemical properties study report.

GLP compliance:

yes

Key result

H:

0 Pa m³/mol

Temp.:

20 °C

H = P / s

At 20 °C, P = 7.1 x 10^-4 Pa

s = (0.8804 / 214.6) x 1000 mol m-3

H = (7.1 x 10^-4) / (0.8804 / 214.6) x 1000 mol m-3

Henry’s Law constant, H = 1.7 x 10 ^-4 Pa.m3.mol-1

The vapour pressure of the test material was found to be 1.4 x 10-3 Pa at 25°C. The volatility of the test material was estimated as Henry’s Law constant to be 1.7 x 10^-4 Pa.m3.mol-1.

Conclusions:

The volatility of the test material was estimated as Henry’s Law constant to be 1.7 x 10^-4 Pa.m3.mol-1.

Executive summary:

Henry’s Law constant for the test material was estimated from the vapour pressure and water solubility data in a guideline physico-chemical properties report.

The volatility of the test material was estimated as Henry’s Law constant to be 1.7 x 10^-4 Pa.m3.mol-1.

Description of key information

Ohnsorge (1994)

Under the conditions of the study the Henry’s Law Constant for the test material was calculated to be 9.981 x 10^-8 (kPa m^3/mol).

Comb (2000b)

The volatility of the test material was estimated as Henry’s Law constant to be 1.7 x 10^-4 Pa.m3.mol-1.

The value from Comb (2000b) has been selected as the key value for chemical safety assessment in line with other EU regulatory schemes.

Key value for chemical safety assessment

Henry's law constant (H) (in Pa m³/mol):

0

at the temperature of:

20 °C

Additional information

Ohnsorge (1994)

The constant H of Henry's Law can be established experimentally for a specific compound or it can be determined from its vapour pressure and water solubility. The study was awarded a reliability score of 2 in accordance with the criteria set forth by Klimisch et al. (1997).

For a reliable calculation the miscibility of the substance with water should not exceed a few mole percent. If the water solubility is high or if the vapour pressure is very low, the result of the calculation is only valid for an orientation.

In the case of the test material both the vapour pressure and the water solubility are known. From these the Henry's Law Constant is calculated.

Under the conditions of the study the Henry’s Law Constant for the test material was calculated to be 9.981 x 10^-8 (kPa m^3/mol).

Comb (2000b)

Henry’s Law constant for the test material was estimated from the vapour pressure and water solubility data in a guideline physico-chemical properties report. The study was awarded a reliability score of 2 in accordance with the criteria set forth by Klimisch et al. (1997).

The volatility of the test material was estimated as Henry’s Law constant to be 1.7 x 10^-4 Pa.m3.mol-1.