Potassium pyrophosphate: Applications and Uses

General Description

Potassium pyrophosphate (K₄P₂O₇) is a water soluble, buffering and chelating agent. It can also be used as an ionic dispersant to form a low viscous solution. It is a biocompatible and a non-toxic compound that is commonly used as a food additive. Potassium pyrophosphate is used in many industrial applications such as surface treatment, boiler descaling, detergent manufacturing, paint and coatings, mining of ore and clay, oil drilling, and synthetic rubber production. It is applied as a food additive, detergent builder, oral care agent. It can be found in herbicides as a spray adjuvant. Potassium pyrophosphate is a white powdery substance that is soluble in water. It is often used as an emulsifier and buffering agent in processed meat, fish and cheese. It is also used as a gelling agent in instant puddings and desserts.¹

Figure 1. Properties of Potassium Pyrophosphate

Applications

Applications of potassium pyrophosphate are as follows:

In Food Production

Potassium pyrophosphate is widely used as emulsifier and stabilizer in food production. Common foods containing potassium pyrophosphateare include chicken nuggets, marshmallows, pudding, crab meat, imitation crab, canned tuna, and soy-based meat alternatives and cat foods and cat treats where it is used as a palatability enhancer. As preservatives: in cottage cheese to delay aging, in aquatic products to maintain moisture and in fruit can to prevent discoloration. As emulsifier: in ham, sausage and cheese to promote emulsification.²

In Beverage

Tetrapotassium Pyrophosphate is widely used as emulsifier, preservatives, humectant, soften agents and thickeners in beverage. As emulsifier, preservatives, humectant, soften agents and thickeners: in dairy drinks to promote emulsification, improve mouthfeel and extend shelf life.²

In Manufacture of Liquid Detergents

Solutions of potassium pyrophosphates are useful in the manufacture of heavy-duty liquid detergents, in which the potassium phosphate solution is blended with dissolved synthetic organic detergents and other additives. They are also useful in manufacture of solid detergents. Other uses are in water treating and conditioning, or in manu facture of water treating compositions. They may also be used as a base solution for formulating liquid fertilizers. Pyrophosphates and tripolyphosphates are known com pounds and are manufactured by heating alkali metal hy drogen orthophosphates in the solid state at elevated tem perature to drive off water of constitution, thus condensing phosphate groups to form phosphoric anhydride linkages.³

In Other Industries

Potassium pyrophosphate is widely used as cleaner agents, Plated conductor in various other industries. As cleaner agents: in metal surface and bottle to clean. As Plated conductor: in plating solution to compose circuit.³

Ecological information of Potassium Pyrophosphate

Potassium pyrophosphate hydrolyses to orthophosphate and sodium ions in aqueous and biological systems. The degradation products of tetrapotassium pyrophosphate are essential nutrients (food elements) for plants, and stimulate the growth of water plants (macrophytes) and/or algae (phytoplankton) and are ubiquitous in the environment. The potential for bioaccumulation is therefore considered to be minimal.⁴

Preparation of Potassium Pyrophosphate

Solid pyrophosphoric acid from the mixer is reacted with KOH liquor. Reaction may be continuous or batch-wise. In batch operation, a charge of caustic potash liquor is placed in a mixing tank equipped with agitator and cooling coils. Solid pyrophosphoric acid is added gradually, mixing continued until the reaction is com plate. The finished pH value of the reaction mixture may be in the range from about 7 to 13. Proportions are in the range of 1 part solid acid to 1.4-3.2 parts of KOH liquor the exact ratio depending upon concentration of the KOH. Temperature and time are not critical but typically the temperature is controlled at about 65°C. and mixing time per batch is about 1 hour. The finished solution is cooled to about room temperature, and then Sent to storage, shipment or use.³

References

1. https://pubchem.ncbi.nlm.nih.gov/compound/Potassium-pyrophosphate

2. https://www.foodsweeteners.com/applications-and-uses-of-tetrapotassium-pyrophosphate

3. Raymond L Copson. US3325244A

4. Safety data sheet of tetrapotassium pyrophosphate. Date of issue: 14/12/2017