Phosphite


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phosphite

[′fä‚sfīt]
(inorganic chemistry)
Salt of phosphorous acid; contains the radical PO33-; an example is normal sodium phosphite, Na3PO3.

Phosphite

 

any of the salts or esters of phosphorous acid (H3PO3). The salts may be monosubstituted, for example, NaH2PO3·2.5H2O.or disubstituted, as in Na2HPO3·5H2O. Most phosphites are difficultly soluble in water; this is not true, however, of phosphites of alkali metals. When calcined, phosphites decompose into the corresponding phosphates and phosphorus derivatives with lower oxidation states, the process including the formation of phosphine (PH3). Phosphites are oxidized in aqueous solutions by halogens and mercury salts, for example, HgCl2, to phosphates. Phosphites are formed when phosphorous acid is neutralized by hydroxides. They are used as reducing agents in inorganic syntheses. Lead phosphite serves as a light stabilizer in the production of polyvinyl chloride.

The esters of phosphorous acid may be mono-[ROP(O)HOH], di-[(RO)2P(O)H], or tri-substituted [(RO)3P], They are obtained from the reactions of phosphorus trichloride with alcohols and alcoholates:

PCl3 + 3ROH → (RO)2P(O)H

PCl3 + 3RONa → (RO)3P

Phosphites are used as stabilizers of polymer plastics and oils and as intermediates in the synthesis of organophosphorus compounds.

References in periodicals archive ?
Change the ratio of phenolic antioxidant (lower) and phosphite melt-processing stabilizer (higher).
Action of the fungicide phosphite on Eucalyptus marginata inoculated with Phytophthora cinnamomi.
These packages were composed of phenolic and phosphite AO in combination with an oligomeric HAS, the concentration of which was comparable to that of the phenolic long-term stabilization.
For example, a mixture of triphenyl phosphite and pyridine is a very convenient medium to promote the condensation and dehydration steps which leads to a quinazolinone via an intermediate benzoxazinone.
Of all of the samples analyzed, only the oldest, the Coonterunah carbonate samples from the early Archean of Australia, showed the presence of phosphite, Other natural sources of phosphite include lightning strikes, geothermal fluids and possibly microbial activity under extremely anaerobic condition, but no other terrestrial sources of phosphite have been identified and none could have produced the quantities of phosphite needed to be dissolved in early Earth oceans that gave rise to life, the researchers concluded.
Potassium phosphite has excellent plant health facilitation qualities and fungicidal activity.
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Effect of phosphite on tomato and pepper plants and on susceptibility of pepper to Phytophthora root and crown rot in hydroponic culture.
A Decision recognising that files forwarded by national plant health regulatory authorities for the appraisal of three active substances (potassium phosphite, acequinocyl and cyflufenamid - Decision C(2003)3128) are in keeping with data and information required by Directive 91/414/EEC, on the marketing of plant protection products, has been adopted by the European Commission.
The Anox product line also includes Anox TB and Anox BB blends incorporating hindered phenols and phosphite antioxidants.
New from the Great Lakes Chemical Corporation are two new polymer stabilizer blends containing both a hindered phenolic antioxidant and a phosphite antioxidant.
65million contract with Ackros Chemicals for an expansion of its phosphite production plant at Manchester.