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).
The addition of tris(nonylphenyl) phosphite (TNPP) as a stabilizer has a profound effect on the melt stability; addition of 0.35 wt% TNPP dramatically improves the stabilization of the viscosity over a range of processing temperatures.
One commercial phosphite widely used as a processing stabilizer for polyolefins and recognized for its hydrolytic stability is {tris (2,4-di-t-butylphenyl)-phosphite} (Irgafos 168, Ciba Specialty Chemicals), here called 168.
The present work is devoted to the study of the behavior of PET/PEN system in presence of triphenyl phosphite (TPP) in order to evaluate its capability of transesterfication inhibition.
The 705 is a secondary antioxidant for linear low-density polyethylene and HDPE, and the company says toxicology testing shows it's safer and higher-performing than conventional solid phosphite antioxidants.
Also new from Dover is HMW, low-volatility, high-phosphorus-content Doverphos S-9228 solid phosphite. It's said to provide unsurpassed hydrolytic stability, which prevents formation of black specs in polyolefins and engineering resins
Effect of the Concentration of Initiator and Functional Monomer (DEM) on the Grafting Degree of LLDPE2 With 1 phr of Triphenyl Phosphite (TTP).
Rick King from BASF will include presentations on a new phosphite processing stabilizer, new processing aids, and UV stabilizers for fire-retardant polyolefins.
Phosphites include Naugard P and Wytox 312 general-purpose secondary antioxidants; Naugard 524 high-performance solid phosphite; and Naugard 492 phenolic/phosphite blend.
Doverphos S-9228 is a patented, free-flowing, high-performance, solid phosphite antioxidant permitted for use in all polymers, with no limitations for temperature conditions of use, and no limitations for types of food.
of the US, is to have a plant in Jubail to make 5,700 t/y of phenolic and phosphite antioxidants, used mainly to stabilise polymeri-sation.
At T [less than or equal to] 280 [degrees] C, the reaction was prevented by addition of a phosphite stabilizer, up to 300 [degrees] C by addition of phosphite and carbodiimide, and up to 325 [degrees] C by addition of phosphite, carbodiimide, and hindered phenolic stabilizers (92).