Condensed phosphorous

The only clearly defined crystalline compositions are three forms of phosphoric acid and hemihydrate, pyrophosphoric acid, and crystalline P O q. The phosphoric acids obtained in highly concentrated solutions or by mixing phosphoric acid with phosphoms pentoxide are members of a continuous series of amorphous (excluding [Y OO]) condensed phosphoric acid mixtures. Mixtures having more than 86% P2O5 contain some cyclic metaphosphoric... 

The condensed phosphoric acids are hygroscopic and exhibit a variety of physical forms at room temperature. The material appears oily at 72—82 wt % P20 viscous and gummy at 82—90 wt % P2O5 and is a mixture of glassy and crystalline material at 90 wt %. 

Commercial condensed phosphoric acids are mixtures of linear polyphosphoric acids made by the thermal process either direcdy or as a by-product of heat recovery. Wet-process acid may also be concentrated to - 70% P2O5 by evaporation. Liaear phosphoric acids are strongly hygroscopic and undergo viscosity changes and hydrolysis to less complex forms when exposed to moist air. Upon dissolution ia excess water, hydrolytic degradation to phosphoric acid occurs the hydrolysis rate is highly temperature-dependent. At 25°C, the half-life for the formation of phosphoric acid from the condensed forms is several days, whereas at 100°C the half-life is a matter of minutes. 

Pyrophosphoric (diphosphoric) acid, H4P2O2, is the only condensed phosphoric acid definitely obtainable ia crystalline form. It has a theoretical P2O5 content of 79.8%. However, Hquid polyphosphoric acid of such content shows by analysis only 42.5% the remainder is phosphoric acid and... 

Condensed Phosphoric Acid. The largest use of polyphosphoric (superphosphoric) acid is as an intermediate in the production of high quahty Hquid fertilizers. The TVA pioneered the development of electric-furnace superphosphoric acid for this appHcation. However, wet-process superphosphoric acid prepared by evaporation of water from wet-process phosphoric acid has almost completely replaced furnace-grade acid in fertilizer manufacture. 

The reaction of condensed phosphoric acid with castor oil gave a poly-phosphoric acid ester, which after neutralization with ammonia shows a high wetting power [32]. Glycerol trioleate was reacted with octametaphosphoric acid at 40°C in the presence of acetic acid anhydride. The reaction product was neutralized with triethanolamine [32,33]. 

There also exists interference from diphosphoric acid, other more highly condensed phosphoric acids, and their organic derivatives. The free phosphoric acid can be determined as a heteropolyacid complex of phosphoric acid and ammonium molybdate. Afterward the complex is reduced by stannum II chloride to molybdenum blue. The amount of this dye can be measured photometricly at 625 nm. Organic derivatives of phosphoric acid and condensed phosphoric acids do not interfere with this method. 

Kiba et al. [93] has described a method for determining this element in marine sediments. The sample is heated with a mixture of potassium dichromate and condensed phosphoric acid (prepared by dehydrating phosphoric acid at 300 °C). The ruthenium is distilled off as RuC>4, collected in 6 M hydrochloric acid-ethanol and determined spectrophotometrically (with thiourea) or radiometrically. Osmium is separated by prior distillation with a mixture of condensed phosphoric acid and Ce(S04)2. In the separation of ruthenium-osmium mixtures recovery of each element ranged from 96.8 to 105.0%. 

Two examples of condensed phosphoric(V) acids are heptaoxo-diphosphoric(V) (pyrophosphoric) and polytrioxophosphoric (meta-phosphoric) acids. 

Condensed Phosphoric Acid Copper Acetate Copper Acetoarsenite Copper Arsenite Copperas... 

When the synthetic procedure to prepare Pt2(P20sH2)4- (equation 441) is carried out at higher temperature, a higher oligomeric complex with platinum(U) centers coupled by an oligomeric condensed phosphorous acid ligand is formed. Little information is known about the complex except that the intense absorption chromophore is now at 580 nm and the emission in the red at 650 nm.1501... 

Condenser, Liebig, 36-inch P. 44 Condenser, phosphoric acid P. 52 Conductivity apparatus Chapter III Connector, brass P. 17 Cork borers, sizes 1-3 Crucible, clay, with cover, 30 gram, 3f X 3 -inch, P. 10, 11, 20, 22, 59 Crucible, clay, with cover, size I, 4J X 51-inch, P. 66, 72 Crucible, porcelain, with cover, 15 cc. Crucible, porcelain, with cover, 100 cc. P. 39... 

Amido-derivatives of Phosphorous and Orthopbosphoric Acids—Amido- and Imido-derivatives of Metaphosphoric Acid.—Amides and Imides of Condensed Phosphoric Acids—Nitrilophosphoric Acids—Amido-, Imido- and Nitrilo-thiophosphoric Acids—Phosphorus Halonitrides or Amidohalides— Phosphorus Nitride. 

The Condensed Phosphoric Acids. Phosphoric acid easily undergoes the process of condensation. Condensation is the reaction of two or more molecules to form larger molecules, either without any other products (in which case the condensation is also called polymerization), or with the elimination of small molecules, such as water. Condensation of two phosphoric acid molecules occurs by the reaction of two... 

Larger condensed phosphoric acids also occur, such as triphosphoric add, HgPgOjo. The interconversion of triphosphates, pyrophosphates, and phosphates is important in many bodily processes, including the absorption and metabolism of sugar. These reactions occur at body temperature under the influence of special enzymes (Chap. 30). 

An important class of condensed phosphoric acids is that in which each phosphate tetrahedron is bonded by oxygen atoms to two other tetrahedra. These acids have the composition (HPOgJ, with x - 3,4, 5,6, . They are called the metaphosphoric acids. Among these acids are tetrametaphosphoric acid and hexametaphosphoric acid. 

The coHrro/fe(i hydrolysis of P4O10 is sometimes useful as a means of preparing condensed phosphoric acids. In principle, the condensation of phosphate ions (e.g. reaction 14.131) should be favoured at low pH, but in practice such reactions are usually slow. 

The simplest condensed phosphoric acid, H4P2O7, is a solid at 298 K and can be obtained from reaction 14.128 or, in a purer form, by reaction 14.132. It is a stronger acid than H3PO4 (Table 14.7). 

Condensed phosphoric acid EINECS 232-417-0 HSDB 1176 Phospholeum Polyphosphoric acid Polyphosphoric acids ... 

Un-ionized derivatives of the condensed phosphoric acids are also prepared thermally, using various proportions of phosphorus pentoxide with the smallest member of the desired family of compounds " e.g. ... 

Condensed phosphoric acids or condensed phosphates are usually... 

MON] Monk, C. B., The condensed phosphoric acids and their salts. Part II. Pyrophosphates, J. Chem. Soc., (1949), 423-427. Cited on page 362. 

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... 

Hydrogen ion (H ) and hydroxyl ion OH ) are common catalysts in aquatic systems. The effect of their catalysis is manifested by changes in reaction rate that occur with changes in pH. For example, one of the major constituents of household synthetic detergents is the salt of condensed phosphoric acid such as pyrophosphoric acid, H4P2O7, and tripo-lyphosphoric acid, H5P3OKJ, These compounds react with water in a reaction known as hydrolysis to form orthophosphoric acid thus ... 

An ester phosphate can be added to improve the flame retardancy of PPE compositions. Preferred are condensed phosphoric acid esters [76]. 

C.Y. Shen and D.Y. Dyroff, Condensed phosphoric acids and condensed phosphates. Prep. Inorg. Reactions, 5, 157, 1968. 

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