Pyrofosfáts

Pyrofosfáts, also known as pyrophosphates, are a class of inorganic compounds with the general formula [P₂O₇]⁴⁻. They are derived from pyrophosphoric acid, H₄P₂O₇, which is formed by the dehydration of two phosphoric acid molecules. This dehydration process involves the removal of a water molecule. Pyrofosfáts are characterized by a P-O-P linkage, a central oxygen atom bridging two phosphorus atoms. This linkage is a key feature that distinguishes them from orthophosphates, which contain only single phosphorus-oxygen bonds.

In aqueous solutions, pyrofosfáts can exist in various protonated forms depending on the pH. They are generally stable in neutral or alkaline solutions but readily hydrolyze to orthophosphate ions in acidic conditions. This hydrolysis reaction can be catalyzed by acids or enzymes. Pyrofosfáts are found naturally in living organisms, where they play crucial roles in cellular metabolism. For instance, adenosine triphosphate (ATP), the primary energy currency of cells, releases pyrophosphate upon hydrolysis, driving many biochemical reactions.

Industrially, pyrofosfáts are used in a variety of applications. Sodium and potassium pyrofosfáts are commonly employed as food additives, acting as leavening agents in baked goods, emulsifiers, and sequestrants to prevent metal ion interactions that can cause spoilage or discoloration. They are also utilized in toothpaste formulations to inhibit tartar formation by binding calcium ions. In metal treatment, pyrofosfáts can be used for cleaning and surface preparation. Their chelating properties also make them useful in detergents and textile processing.