reaction mass of potassium tetrafluoride and tripotassium hexafluoroaluminate

Endpoint summary

Additional information

Multiconstituent ‘Reaction mass of potassium aluminium tetrafluoride and tripotassium hexafluoroaluminate’ is an inorganic white odourless powder with a high melting point (range of 560 – 600˚C). The target substance [reaction mass of potassium aluminium tetrafluoride and tripotassium hexafluoroaluminate] is similar in terms of composition to source substance 1 (SS1), aluminium potassium fluoride. Both substances are multi-constituent substances with the same major (~70%) component (KAlF4). The major constituent, other constituents and impurities present in both of these substances are all potassium fluoroaluminate salts with varying ionic structures and levels of hydration.

A read across justification can be found in IUCLID section 13.2.

Aluminium potassium fluoride is an inorganic white crystalline solid with melting point above 550 °C (NOTOX, 2010). The relative density of aluminium potassium fluoride is 2.94 at 20˚C (NOTOX, 2010). The water solubility of aluminium potassium fluoride is 4.57 g/L at 20 ˚C and pH = 5.8, measured by determining the concentration of aluminium ions in solution (NOTOX, 2010).

Particle size distribution measurements were performed on aluminium potassium fluoride using laser diffraction method, resulting in the following values: D10 = 0.92 μm, D50 = 3.01 μm, D90 = 11.63 μm (Solvay Fluor GmbH, 2009).

 

As the substance is a solid with a melting point well above 300 ˚C, in accordance with Column 2 of REACH Annex VII, studies on boiling point and vapour pressure do not need to be conducted.

The studies on octanol/water partition coefficient, flash point and the stability in organic solvents do not need to be conducted as the substance is inorganic. Surface activity is not predicted based on the substance structure; neither is it a desired substance property. As the substance is a solid, viscosity is not a relevant property. The substance is not expected to be explosive as it does not contain chemical groups which are associated with explosive properties. The performance of the tests on auto-ignition temperature and flammability is considered to be scientifically unjustified in accordance with Annex XI of REACH, as the substance is incapable of reaction with oxygen due to the fact that metal ions are already present in the highest possible oxidation state, and fluorine, being the most electronegative element, cannot be oxidised by oxygen. Water reactivity and pyrophoric properties are not expected for the substance based on the experience in handling the substance. In addition, as the substance is considered to be incapable of reacting exothermically with combustible materials based on its chemical structure, oxidising properties are not expected.

The performance of the study on dissociation constant is considered to be scientifically unjustified in accordance with REACH Annex XI, as, according to Chapter R.7.1.17 of REACH Guidance on information requirements and chemical safety assessment, this property is important for ionisable organic substances. As the substance is an inorganic salt, it is expected to dissociate fully into the respective cation and anion in aqueous solution. Possible dissociation of fluoroaluminate moiety, although it may occur upon dissolution, is considered to be irrelevant for this endpoint.