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Phosphorus Subject

Subjecting phosphorus trifluoride to an electric spark in the absence of air (a disproportion reaction occurs) ... [Pg.712]

A review has recently been published on the subject Phosphorus Radicals . Once again e.s.r. spectroscopy has proved to be an invaluable tool for investigating the kinetics of reactions of phosphorus radicals. Thus the rate constants for the bimolecular reactions of several types of phosphorus radicals, e.g. phosphinyl, phosphonyl, and phosphoranyl radicals, with like species have been determined and shown to be of the same order as, or very close to, the diffusion-controlled limit.These annihilation reactions presumably involve formation of a P—P-bonded dimer. An interesting observation recorded in the paper reporting this work was that t-butoxyl radicals react with (25) to give phosphinyl radicals. [Pg.208]

It was believed for a long time that phosphorus existed only in one (white) allotropic modification but in 1847 A. Schroeter, heating white phosphorus up to 300°C without air, obtained red phosphorus, which, in contrast to the white phosphorus, was neither toxic nor combustible in air. In 1934 P. Bridgeman obtained the third modification, namely, black phosphorus, having subjected phosphorus to heating under high pressure. [Pg.38]

Dichlorine h ptoxide, CljO, is the most stable of the chlorine oxides. It is a yellow oil at room temperature, b.p. 353 K, which will explode on heating or when subjected to shock. It is the anhydride of chloric(VlI) acid (perchloric acid) from which it is prepared by dehydration using phosphorus(V) oxide, the acid being slowly reformed when water is added. [Pg.336]

A wide variety of animal species are subjected to the administration of drugs during their lifetime.The various animal species can encounter drugs and other dietary additives by different routes and this is dependent on the environment in which they are kept. Intensively reared animals tend to have considerable consistency in the components of their diets and thus are much less likely to encounter the range of naturally produced compounds that extensively produced animals encounter. The desire for less expensive dietary constituents and increased efficiency of use has induced feed manufacturers and producers to add enzyme supplements to diets of most farmed animals to reduce the negative effects of indigestible dietary carbohydrates, refactory proteins and unavailable minerals such as phosphorus. This use of dietary additives to improve nutrient utilization and environmental consequences of feeding animals intensively has been the subject of intense research activity in the last five years. " The... [Pg.90]

In an effort to prepare 1 2-dihydropapaverine, Buck dehydrated with phosphoryl chloride, and subjected the product (V) to catalytic reduction, followed by the action of phosphorus pentachloride in the cold. The final product was assumed to be 1 2-dihydropapaverine but Young and Robinson interpret this synthesis differently, and their formulae (V) and (VI) are given above, the final product being 3 4-dihydropapaverine (VII), which Buck thus prepared for the first time in a crystalline condition, m.p. 97-8° picrate, m.p. 151° perchlorate, m.p. 238° dec.). [Pg.185]

One of the first indications that the antiinflammatory potency of the corticoids could be increased was the observation that incorporation of a 9a-fluoro group in hydrocortisone resulted in a tenfold increase in activity. Treatment of hydrocortisone acetate (170a) with phosphorus oxychloride in pyridine yields the corresponding olefin, 172. This, on being subjected to the reaction sequence depicted in the transformation of 104 to 108 (addition of HOBr, closure to the epoxide and ring opening with HF),... [Pg.191]

Phosphorus appears to have a beneficial effect on the growth rate. At sub-critical temperatures it helps to stabilise the carbide, while at temperatures up to about 900°C the presence of the hard phosphide eutectic network restricts the deformation to which the much more ductile matrix would otherwise be subject. Since the phosphide eutectic melts at about 950°C, irons containing appreciable amounts of this constituent should clearly not be exposed to this temperature. [Pg.1002]

Resistance to corrosion Most authors who compare resistance to corrosion of electroless nickel with that of electrodeposited nickel conclude that the electroless deposit is the superior material when assessed by salt spray testing, seaside exposure or subjection to nitric acid. Also, resistance to corrosion of electroless nickel is said to increase with increasing phosphorus level. However, unpublished results from International Nickel s Birmingham research laboratory showed that electroless nickel-phosphorus and electrolytic nickel deposits were not significantly different on roof exposure or when compared by polarisation data. [Pg.537]

Sometimes lateral chlorination can occur on a methyl or alkylthio substituent, especially when phosphorus pentachloride or its mixtures with phosphoryl chloride are used (91JHC1549). Reactions of 2-methyl-4(I//)-quinoline (67) exemplify this behavior (81CPB1069) (Scheme 31) 2-chloro-3- and -4-methyquinolines are also subject to methyl chlorinations by similar reagents (91JHC1549). Sulfuryl chloride and NCS are also likely to induce a proportion of lateral chlorination (83KFZ1055 86S835). [Pg.288]

Plants are highly sensitive to soil acidity because many equilibria involving plant nutrients are affected by pH. Phosphorus is a primary example. This essential element for plant growth occurs in soils mainly as phosphates, which are subject to phosphate-hydrogen phosphate equilibria. Consequently, phosphorus is... [Pg.1332]

C-Chiral amino phosphorus compounds, particularly 1-amino- and 2-aminoalkanephosphonic acids, have been a subject of interest for organic chemists due to their interesting biological activity7 Among many methods of their... [Pg.180]

The eluate from the Cig cartridge is concentrated by rotary evaporation and the residue is dissolved in n-hexane and then subjected to a cleanup procedure using a Florisil cartridge. The eluate is dried and analyzed by gas chromatography (GC) with nitrogen-phosphorus detection (NPD). [Pg.586]

The reactions of the six-membered chlorocyclophosphazene were studied with a number of aliphatic diamines (169 175), aromatic diamines (176), aliphatic diols (177-179), aromatic diols (180,181) and compounds containing amino and hydroxyl functional groups (169,170,182). This subject has been reviewed (11,16,20). There are at least five different reaction products that are possible (Fig. 19). Replacement of two chlorine atoms from the same phosphorus atom produces a spirocyclic product. Replacement of two chlorine atoms from two different phosphorus atoms in the same molecule produces an ansa product. Reaction of only one end of the difunctional reagent, resulting in the substitution of only one chlorine atom, leads to an open-chain compound. Intermolecular bridged compounds are formed when the difunc-... [Pg.191]

The study of open-chain polyphosphazenes has attracted Increasing attention In recent years, both from the standpoint of fundamental research and technological development. The polyphosphazenes are long chains of alternating phosphorus-nitrogen atoms with two substituents attached to phosphorus. These polymers have been the subject of several recent reviews (1-3). Interest has stemmed from the continuing search for polymers with improved properties for existing applications as well as for new polymers with novel properties. [Pg.268]


See other pages where Phosphorus Subject is mentioned: [Pg.90]    [Pg.90]    [Pg.247]    [Pg.149]    [Pg.16]    [Pg.588]    [Pg.10]    [Pg.544]    [Pg.133]    [Pg.358]    [Pg.383]    [Pg.155]    [Pg.365]    [Pg.327]    [Pg.730]    [Pg.489]    [Pg.360]    [Pg.175]    [Pg.69]    [Pg.162]    [Pg.163]    [Pg.110]    [Pg.1333]    [Pg.303]    [Pg.159]    [Pg.187]    [Pg.191]    [Pg.489]    [Pg.368]    [Pg.1295]    [Pg.296]    [Pg.160]    [Pg.198]    [Pg.165]    [Pg.339]    [Pg.646]   
See also in sourсe #XX -- [ Pg.2 , Pg.3 , Pg.4 , Pg.5 , Pg.7 , Pg.31 ]




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