Registration Dossier

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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Physical & Chemical properties

Endpoint summary

Administrative data

Description of key information

Additional information

Typically the purity of tetrapotassium pyrophosphate is > 90% (dry weight, after excluding water). All impurities present at >1% are other inorganic phosphates or other related inorganic substances, similar to the registered substance, and which do not significantly affect its toxicological and ecotoxicological properties. There are no hazardous impurities present within the substance at levels >0.1%.


Tetrapotassium pyrophosphate has a melting point of >300°C - 1890°C and is considered to be very soluble (67.2 to 69.9 % w/w at 20.0 ± 0.5°C.

). The pH of this solution, observed in the water solubility study, was pH 10.7 -10.9. The water solubility study made the following observations

The effect of temperature over the range 10 to 30°C has been considered not to have had a significant influence on the observed solubility of the test material.

Additionally, an assessment of the solubility of the test material over the environmentally relevant pH range of 4 to 9 gave observed solubilities and final solution pH’s similar to those obtained using unbuffered water. Thus, it can be anticipated that the water solubility of the test material over the pH range 4 to 9 would be constant, essentially due to the low buffering activities seen in the environment.

Tetrapotassium pyrophosphate is not considered to possess any of the following hazardous physico-chemical properties: autoflammability and/or self-ignition, flammability, explosiveness and oxidising properties.