Phosphite

(redirected from Phosphites)
Also found in: Dictionary, Medical.

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 ?
A serious drawback of phosphites is their sensitivity to hydrolysis.
The company's tests show that Weston PDDP and DPDP phosphites provide better bun scorch protection for better bun interior color, even in fire-retardant foams having more severe discoloration problems.
will include added production capacity of Weston liquid and solid phosphite stabilizers, used to improve ultraviolet stability of polymers.
Irgafox 168, 38 and 12 secondary phosphite antioxidants provide stability and protect various polymers from degradation (high temperatures and shear) during processing.
Cyanox 2777 high-performance phenolic/phosphite blend is based on Cyanox 1790 and hydrolysis-resistant tris(2,4-di-tbutylphenyl) phosphite.
We experimented with new combinations of existing traditional phenol and phosphite stabilizers, as well as some new hyperactive stabilizer technologies.
Management of root rot includes preventive culture, chemical, and biological measures, like (i) the use of healthy seedlings that are transplanted to deep, well-drained soils; (ii) appropriate irrigation and fertilization practices and the use of gypsum or limestone soil amendments; (iii) application of potassium phosphite, phosphorous acid, metalaxyl, and aluminum fosetyl; and (iv) the incorporation of organic matter to the soil, which favors the colonization of antagonist microorganisms (AKINSANMI et al.
The combination of phosphite and fungicide applications were used to generate the downy mildew severity gradient in soybean, resulting in a range of disease infection from zero to 8% in 2006/07 and from zero to 42.
Not only does this technology overcome the drawbacks of conventional solid phosphites, but it also allows our customers to capitalise on their latent technology to further enhance the polymer architecture allowing them to meet the needs of the very latest in processing systems, end markets and applications.
Additionally, Moreira and May-De Mio (2007) have observed that captan and phosphites have minor effects on this antagonistic action on T.
Phosphites are liquid products originating from the neutralisation of phosphorous acid (H3PO3) with a base.