Polyphosphates soluble

The corresponding constants were estimated. Polyphosphate solubilities were determined by a cryoscopic method. 

Salt-soluble polyphosphates may be involved in nucleic acid synthesis. The content of salt-soluble polyphosphates in P. shermanii reached a maximum at 72 h (3 mg/g of biomass), and subsequently decreased (Fig. 4.16). The content of polyphosphates soluble in alkali, after an insignificant decrease in the first days of incubation, increased constantly in culture and reached 4 mg/g of biomass at 120 h. The main species is represented by high-molecular-weight polyphosphates, soluble in hot IN perchloric acid their cellular content gradually increased up to 11 mg/g of biomass at 96 h (Fig. 4.16) (Konovalova and Vorobjeva, 1972). 

Inhibitors can be used to control corrosion of aluminum alloys. Chromates, silicates, polyphosphates, soluble oils, and others, are in common use. Inhibitors, however, must be used with care in order to achieve the desired result. Chromates ate effective inhibitors if used in sufficiently high concentrations. However, if concentration is insufficient, corrosive attack may be intensiffed. In addition, chromates impart conductivity to the electrolyte, thereby enhancing galvanic effects and altering the solution potential relationships between cladding and core in alclad alloys. 

Fig. 22. Effects of polyphosphate level and N P20 weight ratio on solubility of ammoniated phosphoric acids at 0°C, where A represents 70% of total P20 as polyphosphate B, 45% and C, 0%, and the various crystallizing phases are (1), (NH H2PO (2), (NH 2HPO (3), (NH g HEgO -HgO) (4),...

Orthophosphate Hquid mixtures are ineffective as micronuttient carriers because of the formation of metal ammonium phosphates such as ZnNH PO. However, micronutrients are much more soluble in ammonium phosphate solutions in which a substantial proportion of the phosphoms is polyphosphate. The greater solubiHty results from the sequestering action of the polyphosphate. The amounts of Zn, Mn, Cu, and Fe soluble in base solution with 70% of its P as polyphosphate are 10 to 60 times their solubiHties in ammonium orthophosphate solution. When a mixture of several micronutrients is added to the same solution, the solubiHty of the individual metals is lowered significantly. In such mixtures the total micronuttient content should not exceed 3% and the storage time before precipitates appear may be much shorter than when only one micronuttient is present. 

Other. A large variety of additives are used in paper-coatiag colors primarily to modify the physical properties of the colors (102). At high soHds concentrations in water, mineral pigment particles tend to associate and form viscous pastes. Dispersants (qv) are used to prevent this and to provide low viscosity slurries. Common dispersants include polyphosphates and sodium polyacrylate [9003-04-7]. Various water-soluble polymers are added to coatiag colors and act as water-retention agents and as rheology modifiers. 

Complex Ion Formation. Phosphates form water-soluble complex ions with metallic cations, a phenomenon commonly called sequestration. In contrast to many complexing agents, polyphosphates are nonspecific and form soluble, charged complexes with virtually all metallic cations. Alkali metals are weakly complexed, but alkaline-earth and transition metals form more strongly associated complexes (eg, eq. 16). Quaternary ammonium ions are complexed Htde if at all because of their low charge density. The amount of metal ion that can be sequestered by polyphosphates generally increases... 

Sequestration forms the basis for detergent and water-treatment appHcations of polyphosphates. Sequestration of hardness ions by sodium tripolyphosphate used in detergent formulations prevents the precipitation of surfactants by the hardness ions. Sodium polyphosphate glass (SHMP) may be added to water system to prevent the formation of calcium or magnesium scales by reducing the activity of the hardness ions. However, if the ratio of cation to polyphosphate is too high at a given pH, insoluble precipitates such as may result instead of the soluble polyphosphate complexes. The... 

Calcium carbonate (calcite) scale formation in hard water can be prevented by the addition of a small amount of soluble polyphosphate in a process known as threshold treatment. The polyphosphate sorbs to the face of the calcite nuclei and further growth is blocked. Polyphosphates can also inhibit the corrosion of metals by the sorption of the phosphate onto a thin calcite film that deposits onto the metal surface. When the polyphosphate is present, a protective anodic polarization results. 

The degree of concentration that can be achieved by RO may be limited by the precipitation of soluble salts and the resultant scaling of membranes. The most troublesome precipitate is calcium sulfate. The addition of polyphosphates to the influent will inhibit calcium sulfate scale formation, however, and precipitation of many of the other salts, such as calcium carbonate, can be prevented by pretreating the feed either with acid or zeolite softeners, depending on the membrane material. 

Inorganic polyelectrolytes exist, too polyphosphates, -0-P(=0)(-0H)-, are the most common (soluble) ones. 

Cyclizations can also be carried out with an esterified oligomer of phosphoric acid called polyphosphate ester, which is chloroform soluble.55 Another reagent of this type is trimethylsilyl polyphosphate (Scheme 11.4, Entry 13).56 Neat methanesul-fonic acid is also an effective reagent for intramolecular Friedel-Crafts acylation (Scheme 11.4, Entry 14).57... 

Various polyphosphates are effective sequestering agents under appropriate conditions. The best known of these is sodium hexametaphosphate (10.14), the cyclic hexamer of sodium orthophosphate. Further examples are the cyclic trimer sodium trimetaphosphate (10.15), as well as the dimeric pyrophosphate (10.16), the trimeric tripolyphosphate (10.17) and other linear polyphosphates (10.18). All of these polyanions function by withdrawing the troublesome metal cation into an innocuous and water-soluble complex anion by a process of ion exchange as shown in Scheme 10.7 for sodium hexametaphosphate. Hence these compounds are sometimes referred to as ion-exchange agents. 

The inositol polyphosphate 5-phosphatases belong to a family of enzymes that terminate the signals generated by inositol lipid kinases and PLC. To date, two major types of 5-phosphatase have been identified, both of which share a common 5-phosphatase domain of approximately 300 amino acids, with several highly conserved motifs. Type-I enzymes are 43-65 kDa and preferentially hydrolyze 1(1,4,5)P3 and 1(1,3,4,5)P4, with the attendant formation of I(1,4)P2 and 1(1,3,4)P3, but have little or no activity towards membrane-bound phosphoinositides. The pro-totypic form of a type-15-phosphatase is a 43 kDa protein that is post-translationally modified by farnesylation of the carboxyl terminus CAAX motif this modification juxtaposes the enzyme with the membrane. Type-II enzymes are larger (75-160 kDa) and will hydrolyze both water-soluble inositol phosphates and lipids that... 

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). 

The extent of process recovery is often limited by the fouling of membranes from sparing soluble precipitates. Antisealants are added during pretreatment to increase the solubility of salts likely to precipitate, enabling the membrane process to achieve a higher recovery before fouling occurs. Antisealants can be a number of polymeric substances (typically polyphosphates, phosphonates and polycarbonic acids), and as there is no treatment process to remove antisealant, they will be present in the membrane concentrate discharge. 

The corrosion process can be inhibited by the addition of phosphate or polyphosphate ions [344], inorganic inhibitors as, for example, chromate ions [336], adsorbed alcohols [345], adsorbed amines, competing with anions for adsorption sites [339,] as well as saturated linear aliphatic mono-carboxylate anions, CH3(CH2)n-2COO , n = 7 — 11, [24]. In the latter case, the formation of the passive layer requires Pb oxidation to Pb + by dissolved oxygen and then precipitation of hardly soluble lead carboxylate on the metal surface. The corrosion protection can also be related to the hydrophobic character of carboxylate anions, which reduce the wetting of the metal surface. 

Form I polyammonium catena-polyphosphate contains the shortest long-chain anions of several polymorphic forms having the same chemical composition.1 It is slightly soluble in water and gives a cloudy, viscous solution. The solubility increases with the quantity of solid phase present the apparent solubility of the pure compound at 25° has been estimated to be 0.15 g per 100 g of water.1 The compound is more soluble in hot water or in the presence of other dissolved... 

The first two components are the active surfactants, whereas the other components are added for a variety of reasons. The polyphosphate chelate Ca ions which are present (with Mg ions also) in so-called hard waters and prevents them from coagulating the anionic surfactants. Zeolite powders are often used to replace phosphate because of their nutrient properties in river systems. Sodium silicate is added as a corrosion inhibitor for washing machines and also increases the pH. The pH is maintained at about 10 by the sodium carbonate. At lower pH values the acid form of the surfactants are produced and in most cases these are either insoluble or much less soluble than the sodium salt. Sodium sulphate is added to prevent caking and ensures free-flowing powder. The cellulose acts as a protective hydrophilic sheath around dispersed dirt particles and prevents re-deposition on the fabric. Foam stabilizers (non-ionic surfactants) are sometimes added to give a... 

---