Tripotassium phosphate, also called tribasic potassium phosphate is a water-soluble

salt Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in the form of a natural crystalline mineral is known as rock salt or halite. Salt is present in vast quantitie ...

with the chemical formula K₃PO₄^.(H₂O)_x (x = 0, 3, 7, 9). Tripotassium phosphate is basic.

Production

Tripotassium phosphate is produced by the neutralization of phosphoric acid: H3PO4 + 3KOH -> K3PO4 + 3H2O

Use in organic chemistry

Tripotassium phosphate has few industrial applications. It is used as an inert, easily removed proton acceptor in

organic synthesis Organic synthesis is a special branch of chemical synthesis and is concerned with the intentional construction of organic compounds. Organic molecules are often more complex than inorganic compounds, and their synthesis has developed into one o ...

. Some of the reactions are listed below: # The hydrate (K3PO4\cdot H2O) has been used to catalyze the deprotection of BOC amines. Microwave radiation is used to aid the reaction. # As a catalyst for the synthesis of unsymmetrical diaryl ethers using mimchem>BF4 as the solvent. Aryl methane-sulfonates are deprotected and then followed by a

nucleophilic aromatic substitution A nucleophilic aromatic substitution is a substitution reaction in organic chemistry in which the nucleophile displaces a good leaving group, such as a halide, on an aromatic ring. Aromatic rings are usually nucleophilic, but some aromatic compou ...

(S_NAr) with activated aryl halides. # As a base in the cross-coupling reaction of aryl halides with terminal alkynes. It also plays a role in the deacetonation of 4-aryl-2-methylbut-3-yn-2-ol intermediates. # As the base in the cross-coupling reaction between aryl halides and phenols or aliphatic alcohols.

Use in foods

Tripotassium phosphate can be used in foods as a

buffering agent A buffer solution (more precisely, pH buffer or hydrogen ion buffer) is an aqueous solution consisting of a mixture of a weak acid and its conjugate base, or vice versa. Its pH changes very little when a small amount of strong acid or base is ...

emulsifying agent An emulsion is a mixture of two or more liquids that are normally immiscible (unmixable or unblendable) owing to liquid-liquid phase separation. Emulsions are part of a more general class of two-phase systems of matter called colloids. Although ...

, and for nutrient fortification. It can serve as a sodium-free substitute for

trisodium phosphate Trisodium phosphate (TSP) is the inorganic compound with the chemical formula . It is a white, granular or crystalline solid, highly soluble in water, producing an alkaline solution. TSP is used as a cleaning agent, builder, lubricant, food a ...

. The ingredient is most common in dry cereals but is also found in meat, sauces, and cheeses.

Hazards

It is somewhat basic: a 1% aqueous solution has a pH of 11.8.

References

{{Potassium compounds Potassium compounds Phosphates Food emulsifiers E-number additives Inorganic fertilizers