Registration Dossier

Physical & Chemical properties

Endpoint summary

Administrative data

Description of key information

Additional information

The DOWFAX 2A1 substance is a white powdered solid in its pure form; however, the substance is marketed and used exclusively in the form of concentrated aqueous solutions. The physical/chemical properties have been characterized for the pure solid substance, where possible. This solid form does not have defined melting or boiling points, as thermal decomposition occurs at temperatures below which these transitions of state will occur. The density of this solid was determined to be 0.972 g/cm3 at 20 °C. The substance has very low vapor pressure, and the extrapolated vapor pressure at 20 °C (< 1.33 x 10 -8 Pa) falls at or below the lower measurement limit. The substance is also miscible in water, which combined with low vapor pressure, gives the substance virtually no potential for volatilization from water. The substance is marketed as a surfactant, and a 1% wt. solution in pure water has a surface tension of 37.3 mN/m at 20 °C. The powder form of DOWFAX 2A1 is not classified as flammable, as it was shown to be not flammable on contact with air and water, and auto-ignition of the substance could not be achieved. Flash point was not determined, as the solid substance does not have measurable melting and boiling points. The substance is also not classified as explosive or oxidizing, as the structure of the substance lacks the relevant atoms/functional groups associated with these properties. Furthermore, because the substance is marketed and used only in its aqueous solution form, these flammability and reactivity parameters are largely irrelevant. DOWFAX 2A1 is highly stable in water, and is used in formulations containing other reagents such as caustic and bleach. Stability in organic solvents is not a critical/relevant parameter, as the substance is relatively insoluble in organic solvents and water is used as the carrier solvent/vehicle for testing of fate and toxicological properties. The predicted acid dissociation constants (pKa) for the ionizable sulfonate groups are less than 0, indicating the substance to be fully ionized (anionic) at any pH relevant to physiological or environmental conditions.