Trisodium phosphate
From Wikipedia, the free encyclopedia
| Trisodium phosphate[1] | |
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| IUPAC name |
Trisodium phosphate
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| Other names | Sodium phosphate tribasic |
| Identifiers | |
| CAS number | 7601-54-9  ,10101-89-0 (dodecahydrate) |
| PubChem | 166757 |
| EC number | 231-509-8 |
| RTECS number | TC9575000 |
| Properties | |
| Molecular formula | Na3PO4 |
| Molar mass | 163.94 g/mol |
| Density | 1.620 g/cm3 (dodecahydrate) |
| Melting point |
73.5 °C decomp. (dodecahydrate) |
| Solubility in water | 1.5 g/100 mL (0 °C) |
| Basicity (pKb) | 2.23 |
| Structure | |
| Crystal structure | Trigonal |
| Hazards | |
| MSDS | ICSC 1178 |
| EU Index | Not listed |
| Flash point | Non-flammable |
| Related compounds | |
| Related compounds | Monosodium phosphate Disodium phosphate Tripotassium phosphate |
| (what is this?) (verify) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) |
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| Infobox references | |
Trisodium phosphate (TSP) is a cleaning agent, food additive, stain remover and degreaser. It is a white, granular or crystalline solid, highly soluble in water producing an alkaline solution. The item of commerce is often partially hydrated and may range from anhydrous trisodium phosphate, Na3PO4, to the dodecahydrate, Na3PO4·12H2O. Most often found in white powder form, it can also be called trisodium orthophosphate or just plain sodium phosphate. Trisodium phosphate was at one time extensively used in formulations for a wide variety of consumer grade soaps and detergents, but ecological problems have largely ended that practice, at least in the western world.
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[edit] Uses
[edit] Cleaning
The major use for trisodium phosphate is in cleaning agents. The pH of a 1% solution is 12, and the solution is sufficiently alkaline to saponify grease and oils. In combination with surfactants, TSP is an excellent agent for cleaning everything from laundry to concrete driveways. This versatility, coupled with lack of toxicity and low manufacturing price, made TSP the preferred basis for a plethora of cleaning products sold in the mid-20th century. TSP is still sold, and used, as a cleaning agent, but during the late 1960s in the United States, overuse led to a series of ecological problems.
By the end of the 20th century, many products that formerly contained TSP are now manufactured with TSP Substitutes, which consist mainly of sodium carbonate along with various admixtures of nonionic surfactants and a limited percentage of sodium phosphates.
TSP is commonly used after cleaning with mineral spirits in order to remove hydrocarbon residues.[citation needed] TSP may be used with household chlorine bleach in the same solution without hazardous reactions.[2] This mixture is particularly good for removing mildew.
Although it is still the active ingredient in some toilet bowl cleaning tablets, TSP is generally not good for cleaning bathrooms, because it can corrode metal and can damage grout.[3]
[edit] Use as a Flux
In the United States, trisodium phosphate is an approved flux for use in hard soldering joints in medical grade copper plumbing. The flux is applied as a concentrated water solution and dissolves copper oxides at the temperature used in copper brazing. Residues are fully water soluble and can be rinsed out of plumbing before it is put in service.
TSP is used as an ingredient in fluxes designed to deoxygenate nonferrous metals for casting.
TSP can be used in ceramic production to lower the flow point of glazes.
[edit] Exercise performance enhancement
TSP has gained a following as a nutritional supplement that can improve certain parameters of exercise performance.[4] The basis of this belief is the fact that phosphate is required for the energy-producing Krebs cycle central to aerobic metabolism. However, it is generally considered to be a bad idea to ingest compounds that are sufficiently caustic to dissolve cell membranes. Phosphates are available from a number of other sources that are much milder than TSP. While trisodium phosphate is not toxic per se, it is severely irritating to gastric mucosa unless used as part of a buffered solution.
[edit] Ecological Damage
TSP was once the major component of laundry and dishwashing detergents. However, the phosphate contained in these products was not removed from wastewater during treatment and was then subsequently discharged into watersheds and larger bodies of water. There, phosphate was often the limiting agent for waterborne plant life, and the excess caused algal blooms and subsequent eutrophication of lakes and estuaries. In the United States, the Clean Water Act severely limited the use of phosphates in general, and trisodium phosphate in particular, in consumer cleaning products.
Products sold as TSP substitute, containing soda ash and zeolites, are promoted as a direct substitute. However, sodium carbonate is not as strongly basic as trisodium phosphate, making it less effective in demanding applications. Zeolites are added to laundry detergents as bulking agents that rapidly break down in water and are essentially nonpolluting. Even cleaning products labeled as TSP may contain other ingredients as well, and may, in fact, be less than half trisodium phosphate.[5]
[edit] References
- ^ Merck Index, 12th Edition, 8808.
- ^ Home Improvement — General — House siding, allexperts.com
- ^ TSP ... Cleaning for the Big Dogs, naturalhandyman.com
- ^ Folland JP et al. (2008). Journal of Science and Medicine in Sport 11: 464—468.
- ^ MSDS for TSP substitute
