Tetrapotassium pyrophosphate (K4O7P2), or TKPP, is a commercial chemical produced by many major companies throughout the world. TKPP is commercially available as a free-flowing, white, granular solid. TKPP has been certified by the U. S. Department of Transportation as a nontoxic compound. TKPP can dissolve in water readily with a saturated solubility of 187 g/100 g water at 25 °C and a density as high as 1.74 g/cm3. Therefore, TKPP can potentially be used for high-density well drilling as completion or workover fluid[1].

Potassium pyrophosphate dissociates completely in aqueous media to potassium ions (K+) and pyrophosphate ions (P2O7 4-). The pyrophosphate anion is unstable in aqueous solution and hydrolyses into inorganic phosphate. Both potassium ions (K+) and phosphate ions (HPO4 2-) are ubiquitous in the environment. Both ions are essential to all living organisms, and their intracellular and extracellular concentrations are actively regulated. Neither potassium pyrophosphate nor its dissociated ions are expected to bioaccumulate. Potassium pyrophosphate is expected to be of low toxicity concern to aquatic organisms based on a similar compound.

In the food industry, it is used as an emulsifier, quality modifier, chelating agent, and to help improve the taste of cakes and pastries. It is used in chicken nuggets, marshmallows, cheese, cakes, ice cream, pastries, pudding, crab meat, imitation crab, canned tuna, and soy-based meat alternatives[2].

Potassium pyrophosphate, tetrabasic is already permitted for use as a food additive in various foods as specified in the List of Permitted Emulsifying, Gelling, Stabilizing or Thickening Agents, the List of Permitted Food Additives with Other Accepted Uses, and the List of Permitted Sequestering Agents.

References

[1] Jingmao Zhao . “Corrosion of N80 Steel in a Concentrated Tetrapotassium Pyrophosphate Solution and Corrosion Control by Vanadates.” International Journal of Electrochemical Science 14 7 (2019): Pages 6209-6222.

[2] Notice of Modification to the Lists of Permitted Food Additives to Enable the Use of Potassium Pyrophosphate, tetrabasic in Unstandardized Foods - Reference Number: NOM/ADM-0128 - Canada.ca