Chemistry:Tripotassium phosphate
Unit cell of tripotassium phosphate.
| |
| Names | |
|---|---|
| IUPAC name
Potassium phosphate
| |
| Systematic IUPAC name
Potassium tetraoxidophosphate(3−) | |
| Other names
Potassium phosphate, tribasic
| |
| Identifiers | |
3D model (JSmol)
|
|
| ChEBI | |
| ChemSpider | |
| EC Number |
|
PubChem CID
|
|
| UNII | |
| |
| |
| Properties | |
| K3PO4 | |
| Molar mass | 212.27 g/mol |
| Appearance | White deliquescent powder |
| Density | 2.564 g/cm3 (17 °C) |
| Melting point | 1,380 °C (2,520 °F; 1,650 K) |
| 90 g/100 mL (20 °C) | |
| Solubility in ethanol | Insoluble |
| Basicity (pKb) | 1.6 |
| Structure[1] | |
| Primitive orthorhombic | |
| Pnma, No. 62 | |
a = 1.123772 nm, b = 0.810461 nm, c = 0.592271 nm[1]
| |
| Hazards[2] | |
| Main hazards | Irritant |
| Safety data sheet | MSDS |
| GHS pictograms | |
| GHS Signal word | Warning |
| H319 | |
| P264, P280, P305+351+338, P337+313 | |
| NFPA 704 (fire diamond) | |
| Flash point | Non-flammable |
| Related compounds | |
Other cations
|
Trisodium phosphate Triammonium phosphate Tricalcium phosphate |
Related compounds
|
Monopotassium phosphate Dipotassium phosphate |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
| Infobox references | |
Tripotassium phosphate, also called tribasic potassium phosphate[3] is a water-soluble salt with the chemical formula K3PO4.(H2O)x (x = 0, 3, 7, 9).[4] Tripotassium phosphate is basic.
Production
Tripotassium phosphate is produced by the neutralization of phosphoric acid with potassium hydroxide:[4]
Use in organic chemistry

Tripotassium phosphate has few industrial applications.
It is used as an inert, easily removed proton acceptor in organic synthesis. Some of the reactions are listed below:
- The hydrate () has been used to catalyze the deprotection of BOC amines. Microwave radiation is used to aid the reaction.[5]
- As a catalyst for the synthesis of unsymmetrical diaryl ethers using [Bmim] as the solvent. Aryl methane-sulfonates are deprotected and then followed by a nucleophilic aromatic substitution (SNAr) with activated aryl halides.[6]
- 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.[7]
- As the base in the cross-coupling reaction between aryl halides and phenols or aliphatic alcohols.[8]
Use in foods
Tripotassium phosphate can be used in foods as a buffering agent, emulsifying agent, and for nutrient fortification. It can serve as a sodium-free substitute for trisodium phosphate. The ingredient is most common in dry cereals but is also found in meat, sauces, and cheeses.[9]
Hazards
Not safe for human consumption, causes irritation in stomach
References
- ↑ 1.0 1.1 Voronin, V. I.; Ponosov, Yu. S.; Berger, I. F.; Proskurnina, N. V.; Zubkov, V. G.; Tyutyunnik, A. P.; Bushmeleva, S. N.; Balagurov, A. M. et al. (2006). "Crystal structure of the low-temperature form of K3PO4". Inorganic Materials 42 (8): 908–913. doi:10.1134/S0020168506080206.
- ↑ "Potassium phosphate" (in en). https://pubchem.ncbi.nlm.nih.gov/compound/62657#section=Safety-and-Hazards.
- ↑ "Potassium phosphate tribasic P5629". https://www.sigmaaldrich.com/catalog/product/SIAL/P5629?lang=en®ion=US&gclid=CjwKCAjwhcjVBRBHEiwAoDe5x4mgjw3D-Q3p-5HkZkBQX2hrkJZmUDb5Qt6FndG1g9fBXnUtTjM26BoC1WQQAvD_BwE.
- ↑ 4.0 4.1 Klaus Schrödter; Gerhard Bettermann; Thomas Staffel; Friedrich Wahl; Thomas Klein; Thomas Hofmann (2012). "Ullmann's Encyclopedia of Industrial Chemistry". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a19_465.pub3.
- ↑ Dandepally, Srinivasa Reddy; Williams, Alfred L. (2009-03-04). "Microwave-assisted N-Boc deprotection under mild basic conditions using K3PO4·H2O in MeOH" (in en). Tetrahedron Letters 50 (9): 1071–1074. doi:10.1016/j.tetlet.2008.12.074. ISSN 0040-4039.
- ↑ Xu, Hui; Chen, Yang (2007-04-30). "C(aryl)-O Bond Formation from Aryl Methanesulfonates via Consecutive Deprotection and SNAr Reactions with Aryl Halides in an Ionic Liquid" (in en). Molecules 12 (4): 861–867. doi:10.3390/12040861. PMID 17851438.
- ↑ Shirakawa, Eiji; Kitabata, Takaaki; Otsuka, Hidehito; Tsuchimoto, Teruhisa (2005-10-10). "A simple catalyst system for the palladium-catalyzed coupling of aryl halides with terminal alkynes" (in en). Tetrahedron 61 (41): 9878–9885. doi:10.1016/j.tet.2005.07.099. ISSN 0040-4020.
- ↑ Niu, Jiajia; Zhou, Hua; Li, Zhigang; Xu, Jingwei; Hu, Shaojing (2008-10-03). "An Efficient Ullmann-Type C−O Bond Formation Catalyzed by an Air-Stable Copper(I)−Bipyridyl Complex" (in EN). The Journal of Organic Chemistry 73 (19): 7814–7817. doi:10.1021/jo801002c. ISSN 0022-3263. PMID 18771324.
- ↑ Han, James (2020-08-03). "What is Tripotassium Phosphate E340(iii) in Food and Functions in Cereals?" (in en-US). https://foodadditives.net/phosphates/tripotassium-phosphate/.

