Phosphonates or Phosphonic acids are organic compounds containing one or more C-PO(OH)2 or C-PO(OR)2 (with R=
alkyl, aryl) groups. Bisphosphonateswere first synthesized in 1897 by Von Baeyer and Hofmann. An example of such a bisphosphonate is HEDP. Since the work of Schwarzenbach in 1949, phosphonic acids are known as effective chelating agents. The introduction of an amine group into the molecule to obtain -NH2-C-PO(OH)2 increases the metal binding abilities of the phosphonate. Examples for such compounds are 'iyot', EDTMP and DTPMP. These common phosphonates are the structure analogues to the well-known aminopolycarboxylates NTA, EDTA, and DTPA. The stability of the metal complexes increases with increasing number of phosphonic acid groups. Phosphonates are highly water-soluble while the phosphonic acids are only sparingly soluble. Phosphonates are not volatile and poorly soluble in organic solvents.
AEPn: 2-Aminoethylphosphonic acid
DMMP: Dimethyl methylphosphonate
*HEDP: 1-Hydroxyethane(1,1-diylbisphosphonic acid)
NTMP: Nitrilotris(methylenephosphonic acid)
*EDTMP: 1,2-Diaminoethanetetrakis (methylenephosphonic acid)
*DTPMP: Diethylenetriaminepentakis (methylenephosphonic acid)
*PBTC: Phosphonobutane-tricarboxylic acid
Occurrence in nature
The first natural phosphonate, 2-aminoethylphosphonic acid, was identified in 1959 and occurs in plants and many animals, mostly in membranes. Phosphonates are quite common among different organisms, from prokaryotes to eubacteria and fungi, mollusks, insects and others. The biological role of the natural phosphonates is still poorly understood. Until now no bis- or polyphosphonates have been found to occur naturally.
Properties and uses
Phosphonates have three main properties: they are effective
chelating agents for di- and trivalent metal ions, they inhibit crystal growth and scale formation and they are quite stable under harsh chemical conditions. An important industrial use of phosphonates is in cooling waters, desalination systems, and in oil fields to inhibit scale formation. In pulp and paper manufacturing and in textile industry they are used as peroxide bleach stabilizers, acting as chelating agents for metals that could inactivate the peroxide. In detergents they are used as a combination of chelating agent, scale inhibitor and bleach stabilizer. Phosphonates are also used more and more in medicine to treat various bone and calcium metabolism diseases and as carriers for radionuclides in bone cancer treatments (see Samarium-153-ethylene diamine tetramethylene phosphonate).In 1998 the consumption of phosphonates was 56,000 tons worldwide - 40,000 tons in the US, 15,000 tons in Europe and less than 800 tons in Japan. The demand of phosphonates grows steadily at 3% annually.
The toxicity of phosphonates to aquatic organisms is low. Reported values for 48 h LC50 values for fish are between 0.1 and 1.1 mM. Also the bioconcentration factor for fish is very low.
In nature bacteria play a major role in phosphonate biodegradation. Due to the presence of natural phosphonates in the environment, bacteria have evolved the ability to metabolize phosphonates as nutrient sources. Those bacteria able of cleaving the C-P bond are able to use phosphonates as a phosphorus source for growth. Aminophosphonates can also be used as sole nitrogen source by some bacteria. The polyphosphonates used in industry differ greatly from natural phosphonates such as 2-aminoethylphosphonic acid, because they are much larger, carry a high negative charge and are complexed with metals. Biodegradation tests with sludge from municipal sewage treatment plants with HEDP and NTMP showed no indication for any degradation. An investigation of HEDP, NTMP, EDTMP and DTPMP in standard biodegradation tests also failed to identify any biodegradation. It was noted, however, that in some tests due to the high sludge to phosphonate ratio, removal of the test substance from solution observed as loss of DOC was observed. This was attributed to adsorption rather than biodegradation. However, bacterial strains capable of degrading aminopolyphosphonates and HEDP under P-limited conditions have been isolated from soils, lakes, wastewater, activated sludge and compost.
Phosphonates have properties that differentiate them from other
chelating agents and that greatly affect their environmental behavior. Phosphonates have a very strong interaction with surfaces, which results in a significant removal in technical and natural systems. Due to this strong adsorption, little or no remobilization of metals is expected.No biodegradation of phosphonates during water treatment is observed but photodegradation of the Fe(III)-complexes is rapid. Aminopolyphosphonates are also rapidly oxidized in the presence of Mn(II) and oxygen and stable breakdown products are formed that have been detected in wastewater. The lack of information about phosphonates in the environment is linked to analytical problems of their determination at trace concentrations in natural waters. Phosphonates are present mainly as Ca and Mg-complexes in natural waters and therefore do not affect metal speciation or transport.;
Phosphonates can be synthesized using the
Michaelis-Arbuzov reaction. In one study a α-aminophosphonate is prepared from a condensation reactionof benzaldehyde, anilineand trimethyl phosphitecatalyzed by Copper triflatein a one-pot synthesis["A novel Cu(OTf)2 mediated three component high yield synthesis of α-aminophosphonates" Abhimanyu S. Paraskar and Arumugam Sudalai Arkivoc06-1838EP) pp 183-189 2006 [http://www.arkat-usa.org/ark/journal/2006/I10_General/1838/06-1838EP%20as%20published%20mainmanuscript.pdf Article] ]
Phosphonates are used in the
Phosphonates are one of the three sources of phosphate intake in biological cells (The other two being inorganic phosphate and organophosphate)
Phosphine oxide- OPR3
Phosphate- OP(OR)3methyly phosphonic acid is used as active ingredient in scale inhibitor.
Wikimedia Foundation. 2010.
Look at other dictionaries:
Phosphonate — Phosphonsäure Phosphonate Phosphonate sind Salze und organische Verbindungen der Phosphonsäure. Als Salze existieren primäre ( … Deutsch Wikipedia
Phosphonate — Composés organophosphorés Les composés organophosphorés sont une classe de composés organiques comportant au moins un atome de phosphore. Ils sont d une importance capitale notamment en biochimie car un très grand nombre de composés d intérêt… … Wikipédia en Français
phosphonate — noun Any salt or ester of a phosphonic acid; many of its derivatives have important biological activity … Wiktionary
phosphonate — phos·pho·nate fäs fə .nāt n a salt or ester of a phosphonic acid * * * phos·pho·nate (fosґfo nāt) a salt, anion, or ester of phosphonic acid … Medical dictionary
phosphonate — phos·pho·nate … English syllables
phosphonate — ˈfäsfəˌnāt noun ( s) Etymology: phosphonic acid + ate : a salt or ester of a phosphonic acid … Useful english dictionary
Phosphonate dehydrogenase — In enzymology, a phosphonate dehydrogenase (EC number|22.214.171.124) is an enzyme that catalyzes the chemical reaction:phosphonate + NAD+ + H2O ightleftharpoons phosphate + NADH + H+The 3 substrates of this enzyme are phosphonate, NAD+, and H2O,… … Wikipedia
Phosphonate-transporting ATPase — In enzymology, a phosphonate transporting ATPase (EC number|126.96.36.199) is an enzyme that catalyzes the chemical reaction:ATP + H2O + phosphonateout ightleftharpoons ADP + phosphate + phosphonateinThe 3 substrates of this enzyme are ATP, H2O, and… … Wikipedia
H-phosphonate — Les H phosphonate ou hydrogénophosphonates sont des composés contenant du phosphore au degré d’oxydation III. Propriétés générales En solution, ces composés existent sous la forme d’un équilibre de deux formes tautomères : une forme… … Wikipédia en Français
Samarium-153-ethylene diamine tetramethylene phosphonate — Samarium 153 ethylene diamine tetramethylene phosphonate, Samarium 153 EDTMP, Quadramet, or simply Samarium 153 is a complex of a radioisotope of the lanthanide element Samarium with carrier EDTMP which is used to treat pain when cancer has… … Wikipedia