Methylamine

Henry's Law constant

Description of key information

Calculation with HENRYWIN v3.20 (EPIWIN software by US-EPA): Bond Method: 7.68E-1 Pa*m³/mol; Group Method: 7.31E-1 Pa*m³/mol

Henrys LC [via VP/WSol estimates using User-Entered or Estimated values]: 3.106E-005 atm-m³/mol (this value has been used to estimate the PNECSoil via the Equilibrium Partitioning method)

Key value for chemical safety assessment

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

0.768

at the temperature of:

25 °C

Additional information

The Henry´s Law constant of the test substance was determined by HENRYWIN v3.20 (EPIWIN software) by US-EPA. Henry´s law states that the solubility of a gas in a liquid solution at a constant temperature will be proportional to the partial pressure of the gas which is above the solution (Henry, W., 1803). Sometimes, the term “air/water partition coefficient” refers to the dimensionless Henry´s law constant (HLC) and therefore describes the ration of the equilibrium concentration of a dissolved substance in air and water. HENRYWIN estimates two separate HLC values (one using the group method and one using the bond method). The bond contribution methodology splits a compound into smaller units (one atom to another atom only). The bond method includes individual hydrogen bond values; the group method does not. Using the Bond Method by HENRYWIN, a Henry´s Law Constant of 0.768 Pa*m³/mol was calculated for the substance at 25 °C. The Group Method showed a value of 0.731 Pa*m³/mol at the same temperature. Henrys LC [via VP/WSol estimates using User-Entered or Estimated values]: 3.106E-005 atm-m³/mol (this value has been used to estimate the PNECSoil via the Equilibrium Partitioning method)

The data refers to the uncharged molecule.

A Henry´s Law Constant of 0.000011 atm m³ / mol at 25°C (equals 1.11 Pa m³/mol) for monomethylamine was also referenced in the experimental database of EPIWIN. The original source is indicated as Christie and Crisp (1967).