Polyphosphate chelate

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... 

Building towards models relevant for polymeric DNA and RNA, nucleotides contain a phosphate attached at the 5 or 3 position. The 5 -nucleotides are most commonly studied, for which the phosphate has a pAa 6 for the first protonation step. Unless otherwise noted, throughout this chapter nucleotide will refer to the 5 -phosphate linkage. In nucleotides, metal-phosphate coordination competes with metal-base interactions. Chelate complexes with both phosphate and base coordination can occur when sterically allowed. Thus, transition metal complexes with purine monophosphates tend to exhibit metal coordination to the base N7 position, with apparent hydrogen bonding of coordinated waters to the phosphate. By contrast, more ionic Mg" binds preferentially to the phosphate groups in nucleotide monophosphates. In di- and tri-phosphate complexes such as metal-ATP compounds, the proximity of multiple phosphates generally favors polyphosphate chelate complexes with metal ions. 

Quantitative determination of the various organic and inorganic components detected by the qualitative tests. Most often, ion chromatography is used for determination of sulfate phosphate and polyphosphates chelates such as NTA, EDTA, and gluconate and other lower molecular weight components. Capillary electrophoresis may also be used. Gas chromatography is applied to quantification of solvents and propellants. Specialized tests are required to determine poly aery late builders One quick semi-quantitative test is based on pyrolysis GC-MS of a water extract after addition of tetramethylammonium hydroxide. Peaks of methyl acrylate and methyl fumarate indicate the presence of acrylate and maleate polymers and/or copolymers (14). 

Synthetic organic chelates and natural organic complexes are sometimes more effective agronomically per unit of micronuttient than inorganic forms, but the organic materials are more expensive. The chelates can be used with both orthophosphate and polyphosphate Hquids and suspensions. 

Organophosphonates are similar to polyphosphates in chelation properties, but they are stable to hydrolysis and replace the phosphates where persistence in aqueous solution is necessary. They are used as scale and corrosion inhibitors (52) where they function via the threshold effect, a mechanism requiring far less than the stoichiometric amounts for chelation of the detrimental ions present. Threshold inhibition in cooling water treatment is the largest market for organophosphonates, but there is a wide variety of other uses (50). 

Oxygen chelates such as those of edta and polyphosphates are of importance in analytical chemistry and in removing Ca ions from hard water. There is no unique. sequence of stabilities since these depend sensitively on a variety of factors where geometrical considerations are not important the smaller ions tend to form the stronger complexes but in polydentate macrocycles steric factors can be crucial. Thus dicyclohexyl-18-crown-6 (p. 96) forms much stronger complexes with Sr and Ba than with Ca (or the alkali metals) as shown in Fig. 5.6. Structural data are also available and an example of a solvated 8-coordinate Ca complex [(benzo-l5-crown-5)-Ca(NCS)2-MeOH] is shown in Fig. 5.7. The coordination polyhedron is not regular Ca lies above the mean plane of the 5 ether oxygens... 

Phosphonates exhibit all the properties of polyphosphates, such as threshold effect, crystal distortion, and sequestration, but are superior in their effectiveness. They provide good chelates for calcium, magnesium, iron, and copper and are commonly used where iron fouling is a problem. Their sequestering properties are generally superior to other common chelants, such as EDTA and NTA. 

Phosphate. Addition of secondary Na or K phosphate (i.e. Na2HP04 or K2HP04) causes the precipitation of colloidal calcium phosphate, with concomitant decreases in the concentration of soluble calcium and calcium ion. Polyphosphates, e.g. Na-hexametaphosphate, chelate Ca2+ strongly and dissolve CCP. 

The stability of the caseinate particles in milk can be measured by a test such as the heat stability test, rennet coagulation test, or alcohol stability test. Addition of various phosphates—especially polyphosphates, which are effective calcium complexing agents—can increase the caseinate stability of milk. Addition of calcium ions has the opposite effect and decreases the stability of milk. Calcium is bound by polyphosphates in the form of a chelate, as shown in Figure 5-3. 

Development activities in conjunction with polyphosphate pigments have been focused on the high chelate building potential of acidic aluminum tripolyphosphate with metal ions [5.87]. 

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