Phosphates polyphosphates

Phosphate-polymer control, in industrial water treatment, 26 132-133 Phosphate recognition, 16 794 Phosphate refractory dental dies, compressive strength, 8 289t Phosphate rock, 11 119, 120 minerals in, 19 5, 14 recovery of fluoride from, 14 12-13 U.S. imports for consumption of, 19 15t U.S. production of, 19 17 Phosphates, 18 814-863 19 19. See also Phosphate Polyphosphates aluminum acid, 18 839 ammonium, 11 487 18 835-836 analysis of, 18 851-852 calcium, 18 836-839 condensed, 18 841-852 crystalline, 18 839 dispersants, 8 710t economic aspects of, 18 859-860... 

Condensed (poly) phosphates may exert different effects on calcium utilization than the aforementioned effects of simple (ortho-) phosphates. Polyphosphates have a much greater affinity for calcium than do orthophosphates, and soluble calcium-polyphosphate complexes are readily formed in the gastric and intestinal environments. In addition, polyphosphates must be hydrolyzed by an intestinal alkaline phosphatase (27) prior to absorption. We have found polyphosphates to be incompletely (80.5%) hydrolyzed to orthophosphate during the digestive process in young adult males when calcium intake was low only 56% of a 1 g phosphorus supplement was absorbed from a polyphosphate sources as compared to 71% from an orthophosphate source (5). 

These ideas are readily testable and therefore can constitute a research enterprise. For example, the hydrolysis of polyphosphates to monomeric phosphate is relatively fast in weak aqueous acid and warm temperatures. [129, 205] Curiously, however, the same acidity would promote thermal polyphosphate synthesis under the dehydrating conditions of the heated subterranean mineral pores within a hydrothermal system. Measurement of the stability of polyphosphates in microscopic environments where the activity of water might be low would test the phosphate-polyphosphate conjecture made above. If polyphosphates are not stabilized relative to bulk water solutions, as dissolved within micron-sized mineral pores or within vesicles, perhaps in the presence of dissolved organics, then this hypothesis is in danger. Additionally, the proposed production and delivery of polyphosphates by hydrothermal systems can be tested in an appropriate laboratory setting. 

A. Analysis of Wastewater and Natural Waters. The presence of certain anions in wastewater effluents can cause deterioration of natural water systems. Phosphorous and nitrogen can be present in several chemical forms in wastewaters. Phosphorous is usually present as phosphate, polyphosphate and organically-bound phosphorus. The nitrogen compounds of interest in wastewater characterization are ammonia, nitrite, nitrate and organic nitrogen. Analyses are often based on titrimetric, and colorimetric methods (3). These methods are time consuming and subject to a number of interferences. Ion Chromatography can be used to determine low ppm concentrations of these ions in less than thirty minutes with no sample preparation. 

This Group IIA (or Group 2) element (atomic symbol, Ca atomic number, 20 atomic weight, 40.078 electronic configuration = ls 2s 2p 3s 3p 4s ) loses both As electrons to form a divalent cation of 0.99A ionic radius. Ionic calcium combines readily with oxygen ligands (chiefly water, phosphates, polyphosphates, and carbox-ylates) to form stable metal ion complexes. Ca under-... 

Phosphates, polyphosphates Borates, polyborates Sulfates Halides... 

In certain contemporary organisms, for instance, bacteria and fungi, 3-phospho-D-glyceroyl-phosphate polyphosphate phosphotransferase activity was found (Kulaev and Bobyk, 1971 Kulaev et al., 1971). The phosphate was transferred from 1,3-diphosphoglyceric acid, not to ADP to form ATP, as one could expect from the Meyerhof-Embden-Parnas scheme, but directly to PolyP. This fossil reaction was most expressed in an adenine deficient yeast mutant under cell adaptation to ATP depletion. 

Phosphates Polyphosphates Orthophosphates Antisealants, corrosion control, sequestering agents... 

Total Phosphorus (TP) takes into account orthophosphate, polyphosphates and organic phosphate. Polyphosphates must be hydrolysed and organic phosphate oxidized into orthophosphate form, prior to analysis, usually by oxidizing agents in acid conditions. The orthophosphate content is then quantified by colorimetric method with ammonium molybdate (NF EN ISO 6878). This procedure of detection can be automated by FIA and CFA techniques (NF EN ISO 15681-1 and 2, respectively). The orthophosphate content can be estimated using various techniques including a colorimetric method (NF EN ISO 6878), ionic chromatography (NF EN ISO 10304-1), automated FIA and CFA techniques and colorimetric detection (NF EN ISO 15681-1 and 2, respectively). 

Standard methods for phosphates, polyphosphates, and organic phosphates in environmental samples are predominantly nonchromatographic methods, which are based upon the molybdenum blue method. Within this colorimetric method ammonium molybdate and antimony potassium tartrate react under acidic conditions with dilute solution of phosphorous to form an antimony-phospho-molybdate complex which is then reduced to an intensely blue-colored complex by ascorbic acid. U.S. EPA Methods 365.1 to 365.4 are based upon this chemistry. 

The emulsifying salts most commonly used are citrates, phosphates, polyphosphates, and sodium aluminium phosphates (Caric and Kalab, 1987) (Table XI). Other potential emulsifying agents include gluconates, lactates, malates, ammonium salts, glucono lactones, and tartarates (Price and Bush, 1974). Today, salts are generally supplied as blends of phosphates (e.g., Joha C special) or phosphates and citrates (e.g., Solva NZ 10), tailor-made to the processor s requirements. 

Film-forming anions (phosphates, polyphosphates, and carbonates) can also form sparingly soluble salts on the metal surface that hamper corrosion propagation. These anions can become an active part of rust converters that transform corrosion products into insoluble compounds. For instance, orthophosphoric acid transforms rust into insoluble iron phosphates. 

There is some disagreement about how polyphosphates function as corrosion inhibitors. Generally accepted theory is that, in an aerated system, they cause formation of a protective surface film which contains both iron oxide and phosphorus, perhaps an iron phosphate. Polyphosphates will not work in a system that is devoid of oxygen, nor in a stagnant system. Polyphosphate corrosion inhibition required flow, to replace the iron-phosphate film as fast as it is removed or depleted. Polyphosphates are unstable and subject to problems in high temperature circuits, or where pH fluctuation occurs. Ecological considerations also are involved, because of possible pollution contributions of residual... 

Cathodic inhibitors in near-neutral solutions interfere with the oxygen reduction reaction by restricting the diffusion of dissolved oxygen to the electrode surface. These substances usually form thick surface layers with poor electronic conductivity (the latter is an important prerequisite to avoid oxygen reduction on the film surface). Examples are phosphates, polyphosphates, silicates, borates, and inorganic inhibitors, such as Zn +, which precipitate as Zn hydroxide, and Ca ", which forms calcium carbonate films in the presence of CO3 [3]. These inhibitors... 

The sodium phosphates, polyphosphates, and metaphosphates, the preparation of which is described in this volume (see syntheses 24 to 26), represent a diversified group of compounds their relationships are most easily elucidated by a consideration of their structures. The structural unit that characterizes all phosphates is the PO4 tetrahedron, the phosphorus atom being surrounded tetra-... 

Quantitative estimation of the compounds of simple mixtures of phosphates, polyphosphates, and polymetaphosphates can be effected without too much difiSculty. Determinations of orthophosphate, pyrophosphate, triphosphate, and so-called hexametaphosphate" are usually made on mixtures of soluble phosphates. Total phosphorus content is also determined by hydrolyzing all other phosphates to orthophosphoric acid. No distinctive analytical methods are, however, available for the direct quantitative determination of the cyclic metaphosphates. 

Phosphates. Polyphosphates are normally used to increase waterbinding capacity and to protect against rancidity. The greatest waterbinding effect is obtained with low molecular mass compounds such as pyrophosphate and tripolyphosphate. The effect is based partly on an increase in the ionic strength and partly on a pH increase (Gumpen, 1984). 

Ammonium salts Phosphates, Polyphosphates, Sulphates, Halides. 

The total phosphoms content in the body is about 700 g. The daily requirement is about 0.8—1.2 g. The Ca/P ratio in food should be about 1. Phosphoms, in the form of phosphate, liee or bound as an ester or present as an anhydride, plays an important role in metabolism and, as such, is an essential nutrient. The organic forms of phosphoms in food are cleaved by intestinal phosphatases and, thereby, absorption occurs mostly in the form of inorganic phosphate. Polyphosphates, used as food additives, are absorbed only after prior hydrolysis into orthophosphate. The extent of hydrolysis is influenced by the degree of condensation of the polyphosphates. Table 7.2 includes a compilation of the phosphoms content of some foods. 

The addition of phosphates (polyphosphates) to food affects the hydration of proteins and polysaccharides and their colloidal properties. It is used to increase the water-holding capacity (WHC) capacity, sometimes referred to as water-binding capacity (WBC) when water is added to cured meat and certain meat products. Phosphates also provide the appropriate texture to processed cheeses made from traditional cheese and emulsifying salts, often with the... 

It is very rare that a single inhibitor is used in systems such as cooling water systems. More often, a combination of inhibitors (anodic and cathodic) is used to obtain better corrosion protection properties. The blends which are produced by mbdng of multi-inhibitors are called synergistic blends. Examples include chromate-phosphates, polyphosphate-silicate, zinc-tannins, zinc-phosphates. Phosphonates have been used to cathodically protect ferrous materials. Following are the major applications of synergistic blends of inhibitors. 

Staining Applications Brain spinal cord bacteria chromosomes nicotinic acetylcholine receptor nucleic acids phosphates polyphosphates tocopherol tocopherol acetate ... 

Biological Applications Detecting phosphates, polyphosphates, tocopherol, tocopherol acetate Industrial Applications Spatial light modulators security applications ... 

This type of reaction was first applied to the preparation of polyamides, as discussed above, for which it is somewhat more effective in forming high molecular weight polymers, but it has now been used for the synthesis of a wide variety of aromatic polyesters, either by the self-condensation of hydroxyacids or by the co-condensation of dicarboxylic acids and difunctional phenols.A fairly wide variety of phosphorous compounds can be used as reducing or dehydrating agents in these reactions, in addition to phosphines, including phosphites, chlorophosphates, phosphates, polyphosphates and phosphazenes. In most cases, lithium chloride is added and the reaction is run in either pyridine or an amide solvent system. The reaction has also been found to be catalyzed by tertiary amine salts. 

Complexes with phosphate, polyphosphates, and ADP/ATP have been studied. The first paper reports two resonances at —2 to —4 and —5 to —7 ppm in most of the solutions observed. The other two deal with the ATP/Al " system and use a multinuclear approach to determine the species present. The cation binds to the P and y phosphates of ATP and 2 2 and 2 1 complexes are formed, the latter with a A1 linewidth of typically 2400 Hz at ca. 0 ppm and the former with a 600-Hz-wide line at —10 ppm. There are clear differences between these two groups of workers. 

This group includes materials such as various clay minerals including kaolinites and montmorillonites soluble sulfates and sulfuric acid sodium silicates calcium aluminate cements soluble phosphates, polyphosphates, and phosphoric acid and borates and boric acid. 

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