Phosphorus compound

Phosphorus compoimds are increasingly popular as alternatives to halogenated flame retardants in electrical products. They include  

Red phosphorus can be handled by encapsulating it in a thermosetting polymer with a dust suppressant, but for safety reasons it is usually supplied as a masterbatch for compounding by conventional means. The raw element is susceptible to ignition by sparks or by overheating, although it is not spontaneously flammable like the white variety. If exposed to moisture, it releases toxic phosphine that tends to be converted to phosphate. Light coloured products cannot cmrently be achieved with red phosphorus flame retardant additives. 

When red phosphorus acts in the solid phase, it is oxidised to polyphosphoric acid, a char-former. In the vapom phase, red phosphorus contributes to flame retardancy by a different mechanism, generating free radicals such as PO that neutralise the free radicals promoting combustion. 

Several mechanisms are needed to explain the action of the many different phosphorus compoimds used as FRs. Some of these compounds decompose in the condensed phase to form phosphoric acid or polyphosphoric acid. They can promote charring. Char formation is further enhanced by cellulosics, polyurethanes, phenolics, epoxy resins and EVA copolymers, and there are catalysts that promote it. Phenol-formaldehyde polymers can be used as flame retardants themselves when combined with a more flammable thermosetting polymer to form an interpenetrating network. 

Phosphorus compounds exhibit an enormous variety of chemical and physical properties as a result of the wide range ia the oxidation states and coordination numbers for the phosphoms atom. The most commonly encountered phosphoms compounds are the oxide, haUde, sulfide, hydride, nitrogen, metal, and organic derivatives, all of which are of iadustrial importance. The hahde, hydride, and metal derivatives, and to a lesser extent the oxides and sulfides, are reactive iatermediates for forming phosphoms bonds with other elements. Phosphoms-containing compounds represented about 6—7% of the compound hstiugs ia Chemical Abstracts as of 1993 (1). 

The largest-volume phosphoms compounds are the phosphoric acids and phosphates (qv), ie, the oxide derivatives of phosphoms ia the + 5 oxidation state. With the exception of the phosphoric acid anhydride, P O q, and the phosphate esters, these materials are discussed elsewhere (see Phosphoric acids and phosphates). An overview of phosphoms compounds other than the phosphoric acids and phosphates is given herein. These compounds constitute a large variety of phosphoms compounds that are either nonoxide derivatives or derivatives of phosphoms ia oxidation states lower than + 5. These phosphoms compounds are manufactured only from elemental phosphoms (qv) obtained by reduction of naturally occurring phosphate rock (calcium phosphate). 

Name and CAS Registry Number Oxidation state Molecular Stmcture Basicity and salts 

Kirk-Othmer Encyclopedia of Chemical Technology (4th Edition) 

Higher polymeric forms, eg, (ROP ), also exist (see Phosphoric ACIDS AND PHOSPHATBs). 

Phosphorus Compounds. - The synthesis of the chiral phosphate (494) has been described. The silyl ether ds-Me3SiOCMe=CMeOSiMe3 reacts with Me0P(0)p3 to yield the dioxaphospholen (495). Treatment of the tetramer (496) with boron trifluoride affords the di-co-ordinated phosphorus compound (497). The imines (499) are obtained when the 1,2,3-diaza-phospholine (498) is heated with aryl azides. The oxazaphospholine (500) decomposes to trimethyl phosphate and the nitrile ylide (CF3)2C-N=CPh.  

A reversible migration of the phenyl group from phosphorus to iron has been observed for the system (501) (502).  

Miscellaneous other Systems containing Three Heteroatoms. - Catechol is converted into the 1,3,2-benzodioxathiolan (503) by the action of EtNSFj. The cyclic iminodiacyl peroxide (504) is obtained from the imino-compound MeN(COCl)2 and hydrogen peroxide. The hydroxamic acid HOCPh2-CONHOH reacts with carbonyldi-imidazole to yield the dioxazolone (505). The i.r. and Raman spectra of l,3-dimethyl-l,3-diaza-2-boracyclopentanes (506 R = Cl, Br, or NMc2) have been reported. The zwitterionic salt 

Phosphorus Compounds.—Treatment of the dioxaphospholen (635) with sulphur yields a mixture of the oxathiole (636) and fran -dibenzoylstilbene, PhCOCPh=CPhCOPh. 2-Phenyl-l,3,2-dioxaphospholan (637 R = Ph) dimerizes in solution to a ten-membered-ring compound, which was isolated as (638) by sulphurization. The cyclic thiophosphorous acid (639) exists in equilibrium with the betaine (640) in aqueous ethanol/ The spiro-compound (641), which contains a phosphorus-hydrogen bond, is formed by the action of (637 R = Cl) on diethyl tartrate. The phosphazene (642) spontaneously cyclizes to the spiro-compound (643). Stable derivatives (645) and (646 R = Br) of five-co-ordinate phosphorus have been obtained by the action of bromine on the o-phenylene phosphite (644)/ The chlorine analogue (646 R Cl) reacts with 3,5-dimethylpyrazole to give the corresponding pyrazole derivative (646 R = 3,5-dimethylpyrazol-l-yl), which reversibly dimerizes to the zwitterion (647).  

Koenig, A. Munoz, B. Garrigues, and R. Wolf, Phosphorus Sulfur, 1979,6, 435. 

Gldde and H. Gross, Phosphorus Sulfur, 1979, 7, 57 Z. Anorg. Allg. Chem., 1979, 458, 108. 

The oxide radical (648) exchanges the unpaired electron, as evidenced by e.s.r. spectroscopy.Treatment of the catechol with phosphorus pentachloride yields, inter alia, the spiro-dioxaphospholan (649), which equilibrates with the six-co-ordinate phosphorus acid (650). A hexa-t-butyl-derivative is obtained by the joint action of white phosphorus and triethylamine on 3,5-di-t-butyl-l,2-benzo- 

The oxathiaphospholen derivative (651) is produced by the action of (EtO)2PCl on thiocyanatoacetone, MeCOCH2SCN. Treatment of l,4-di(acetyl-Bu Ph Bu Bu Ph 

1 Introduction. - The effect of phosphorus compounds on poisoning of noble metal catalysts has been widely studied. This section deals with deactivation of 

Catalytic deactivation may occur for a number of reasons, both chemical and physical in nature. Several authors have reported that chemical poisoning of the noble metal catalysts is the primary mechanism for phosphorus compounds. Nevertheless, inhibition also takes place. The difference between phosphorus inhibitors and poisons is that inhibitors absorb weakly on the surface and the process is often reversible. On the other hand poisoning is the irreversible loss of activity due to the strong chemisorption of the impurities in the feed on the catalytic active sites. 

In general, organophosphorus compounds show relatively low thermal stability. They decompose relatively quickly under the process conditions, either being converted to phosphorus pentoxide, or in the presence of water vapour to higher, condensed phosphoric acids. It is phosphorus compounds such as these which reach the surface of the catalyst. Most researchers have concluded that phosphorus poisoning is non-selective and can therefore additionally serve as a model for other non-selective poisons such as lead and zinc. Most researchers have 

Infrared spectral data for phosphorus-containing compounds are covered in this section. Included here are single-bonded compounds (P—H, P—R, and P—O—R). Double bonded P=0 compounds are also included in this section. 

medium bands, at 1090-1075 cm and 840-810 cm Bend, medium band, at 990-885 cm  

Another change is anticipated, whereby foam and coverings for furniture may be drawn further into the legislative net in both Europe and North America. This would accelerate the usage of melamine and phosphorus compounds in foams. 

Brominated compounds will continue to hold much of the engineering plastics sector and thereby some dominance in the electrical and electronics (E E) sector. They will continue to be the most significant products because they are the most cost effective (and efficient) solution to many plastics flame retardancy applications. The EU Waste Electrical and Electronic Equipment (WEEE) directive and its effect on recycling plus the debate about fire safety versus environmental issues (especially in domestic appliances) will continue to attract much attention. 

Borates represent a novel opportunity for synergism with both brominated and non-halogenated flame retardant products. Although known for many years, their time has now, perhaps, arrived as antimony trioxide has come under a cloud. For instance, to capitalise on this opportunity Albemarle, the leading BFR company, is collaborating with US Borax to develop new borate-related technologies. 

R D efforts in halogen-fiee FRs are often aimed at designing a protective closed barrier on the burning polymer surface to reduce heat and mass transfer to the combustion zone. In some polymer applications this can be achieved by the use of intumescent systems. However, these are not always suitable in other apphcations for reasons of water uptake, thermal stability or actual FR performance. Therefore, it is of interest to the material developer to have options available to control the structure of the burning polymer surface layer. In this layer no cracks should appear which could allow for the escape of volatile, ignitable gases and so sustain the combustion process. 

Aliuniniiun trihydrate (ATH) should continue to experience strong growth but there is much competition from mineral suppliers all anxious to launch special precipitated grades and those wilh new surface treatments to make them more effective. The drive is the requirement for lower loadings to preserve the balance of mechanical and physical properties for which the particular plastic system has been chosen. The treatment of hydrophilic ATH particles with hydrophobic coatings, such as fatty acids or silanes, provides for more uniform dispersion in the hydrophobic plastic resins. 

Submitted by LOUIS CENTOFANTI end R. W. RUDOLPH t Checked by MAX LUSTIGf 

The hydrogen exchange of phosphine in aqueous solution was studied by deuterium labelling. The reaction shows little sensitivity to bases other than hydroxide ion, though it shows general acid catalysis, viz. 

Reactions involving a number of phosphonium compounds have received attention .  

Schonberg and Ismailobserved that a permanent orange-red color is produced when a trace of MA is added to a colorless solution of 

During the late 1950s and early 1960s interest was regenerated into the outcome of the reaction and a number of groups studied this reaction. Ramirez et proposed structure 80 since a five coordinated phosphorus compound was isolated. Structure 81 was proposed by Horner and KlupfeP based on conjugate addition, whereas infrared spectroscopic study. 

Chopard and Hudson studied the NMR spectrum of the adduct and observed two methylenic hydrogen atoms, thus ruling out structures 77, 80, and 81. Hudson and Chopard also examined the reaction of chlorosuccinic anhydride 83 with triphenylphosphine in THF, followed by treatment with triethylamine, and obtained a betaine 84. (This product is identical to that obtained from direct reaction of MA -f P03.) 

Osuch et observed that the product obtained from treatment of the triphenylphosphine MA adduct with methanol followed by esterification with diazomethane and that obtained from the following reactions of dimethyl 

the evidences of Hudson and Chopard and Osuch et lead to the conclusion that the adduct is a phosphobetaine and the true structure could be represented by a resonance system. 

P-Hst 2440-2275 Weak to medinm, generally one band, in R3PH+ very broad. In Raman, weak to medium 

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Phosphorus compounds are very important as fertilizers (world use 1976/77 27-3 megatonnes as P2O5) but are widely used in matches, pesticides, special glasses and china ware, alloys (sleels. phosphor bronze), and metal treating (10%), detergents (40%), electrical components (e.g. GaP), foods and drinks (15%). Phosphates are an essential constituent of living organisms. U.S. production of phosphorus 1982 372 000 tonnes. 

Phosphorus content No phosphorus compound should be present ... 

Prolonged oxidation of any phosphorus compound, followed by standing in water, converts it to phosphate(V). This can then be detected by the formation of a yellow precipitate when heated with... 

Although AMI IS generally a sigmrieaiit improvement over MXDO, MXDO gives better results for some classes of molecule, such as some phosphorus compounds. 

Some hydrogen chloride is evolved and small quantities of volatile phosphorus compounds are formed, due to such reactions as the following ... 

Low-valent nitrogen and phosphorus compounds are used to remove hetero atoms from organic compounds. Important examples are the Wolff-Kishner type reduction of ketones to hydrocarbons (R.L. Augustine, 1968 D. Todd, 1948 R.O. Hutchins, 1973B) and Barton s olefin synthesis (p. 35) both using hydrazine derivatives. 

Organophosphorus compounds. Phosphorus-carbon bond fonnation takes place by the reaction of various phosphorus compounds containing a P—H bond with halides or tritlates. Alkylaryl- or alkenylalkylphosphinates are prepared from alkylphosphinate[638]. The optically active isopropyl alkenyl-methylphosphinate 778 is prepared from isopropyl methylphosphinate with retention[639]. The monoaryl and symmetrical and asymmetric diarylphosphi-nates 780, 781, and 782 are prepared by the reaction of the unstable methyl phosphinate 779 with different amounts of aryl iodides. Tnmethyl orthoformate is added to stabilize the methyl phosphinate[640]. 

Carbon-phosphorus bonds are formed by the allylation of various phosphorus compounds. The allyldiphenylphosphine sulfide 346 is formed by the reaction of allylic acetates with lithium diphenylthiophosphide 343[215]. 

Phosphorus is m the same group of the periodic table as nitrogen and tricoordi nate phosphorus compounds (phosphines) like amines are trigonal pyramidal Phos phmes however undergo pyramidal inversion much more slowly than amines and a number of optically active phosphines have been prepared... 

Phosphorus Compounds. Acyclic phosphorus compounds containing only one phosphorus atom, as well as compounds in which only a single phosphorus atom is in each of several functional groups, are named as derivatives of the parent structures listed in Table 1.12. Often these... 

Chlorine Ammonia, acetylene, alcohols, alkanes, benzene, butadiene, carbon disulflde, dibutyl phthalate, ethers, fluorine, glycerol, hydrocarbons, hydrogen, sodium carbide, flnely divided metals, metal acetylides and carbides, nitrogen compounds, nonmetals, nonmetal hydrides, phosphorus compounds, polychlorobi-phenyl, silicones, steel, sulfldes, synthetic rubber, turpentine... 

See also pyrophosphorous acid.) [PHOSPHORUS COMPOUNDS] (Vol 18) Diphosphoric(III,V) acid [14902-77-3]... 

COPPERALLOYS-WROUGHTCOPPERANDWROUGHTCOPPERALLOYS] (Vol7) -phosphor tin deoxidation PHOSPHORUS COMPOUNDS] (Voll8)... 

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