Iron phosphonates

Bujoli B., Pena O., Palvadeau R, Le Bideau J., Payen, C. and Rouxel J., Synthesis, structure and magnetic properties of a new lamellar iron phosphonate, Fe"(C2H5P03) H20, Chem. Mater. 5 (1993) pp. 583. 

Iron Oxychloride as a Precursor to Lamellar Iron Phosphonates by Soft Chemistry... 

Iron oxychloride was prepared from Fe203 and FeQ3 by the usual sealed-tubes technique. All iron phosphonates were obtained according to the following chemical process n mmoles of phosphonic acid react with one mmole of FeOQ in 5 mL of solvent in sealed Pyrex tubes. Some reactions have been also realized in round-bottom flasks under nitrogen. 

Manufacture. Trichloromethanesulfenyl chloride is made commercially by chlorination of carbon disulfide with the careful exclusion of iron or other metals, which cataly2e the chlorinolysis of the C—S bond to produce carbon tetrachloride. Various catalysts, notably iodine and activated carbon, are effective. The product is purified by fractional distillation to a minimum purity of 95%. Continuous processes have been described wherein carbon disulfide chlorination takes place on a granular charcoal column (59,60). A series of patents describes means for yield improvement by chlorination in the presence of dihinctional carbonyl compounds, phosphonates, phosphonites, phosphites, phosphates, or lead acetate (61). 

NOTE Periodic cleaning of softener resin with an iron stripping formulation based on phosphonate or a terpolymer is useful. The cleaner is introduced into the resin bed, perhaps via the brine draw during resin regeneration, at a level of, say, 1 to 2 U.S. pints/cuft (16-32 ml/l) of resin. The regeneration process is temporarily halted for several hours and the resin is allowed to soak the process is then restarted and the stripped iron goes to drain. 

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. 

They also provide useful corrosion inhibition by the adsorption of calcium phosphonate onto iron oxide corrosion products, thus reducing the ferrous metal corrosion rate. Phosphonates can be described as cathanodic corrosion inhibitors. 

Aminotri(methylenephosphonic acid) [ATMP or AMP] is the least expensive phosphonate. It is a good, general-purpose, cost-effective scale inhibitor an effective chelant and the most thermally stable of all the common phosphonates. It is satisfactory up to at least 700 psia. However, if fed as a concentrate AIMP may easily form insoluble calcium phosphonate and it may also affect copper. ATMP has a sequestration value of 870 mg CaC03/g product at a pH level of 11 and for iron, a sequestration value of 150 mg Fe/g product at a pH level of 10. The pentasodium salt has a MW of 409. Examples include Dequest 2000/2006, Mayoquest 1230, Phos -2, Briquest 301-50A, Unihib 305, and Codex 8503. 

NOTE This formula is designed for removing calcium and iron foulants. Use at 300 ppm in the boiler. This produces 37 ppm of active polymer for dispersancy and 18 ppm active phosphonate for threshold stabilization. 

In all the experiments, the main decomposition products were phosphonates, which are also stable in concentrated solutions of Mg and Ca chlorides. In some experiments, pyrophosphate, and in smaller amounts triphosphate, could also be detected. The authors thus assume that the primeval ocean contained phosphonates as a source of phosphorus for reactions leading to biochemically relevant molecules. Iron meteorites could have delivered sufficient reduced phosphorus (Fe3P) to the primeval Earth, so the question of prebiotic phosphorus chemistry should be looked at in more detail in the future (Pasek and Lauretta, 2005). 

The use or safe disposal of the iron residues from zinc production (see Figure 7) presents a major technical problem.204 The use of chelating aminomethylene phosphonic acid extractants such as (28) and (29) to recover iron from these residues has been proposed.205 These give much higher FenI/Znn selectivity than D2EHPA but are more difficult to strip. A reductive-stripping process is proposed.187,205... 

Fluorapatite is the only significant phosphorus-containing mineral in the Earth s crust and schreibersite has been found in iron meteorites. The only organic species to be found containing phosphorus in meteorites are the alkyl phosphonic acids. These are at least promising even if they do not contain the P-O-P phosphoester bond unit. 

A photoinitiated reaction has been reported of trialkyl phosphite with an electron-deficient vinylic halide for which an olefinic carbon is covalently bound to a metallic center (Figure 6.24).92 Unfortunately, only low yields of the target phosphonate are obtained. In another report involving a transition metal bound to carbon, an acetylenic carbon covalently bound to an iron center has been found to undergo... 

Using phosphonic acid as a collector if cations are present in the flotation pulps affects the cassiterite flotation negatively. High iron levels in particular have a strong depressing effect on flotation using phosphonic acid. 

A phenomenon observed in both laboratory and pilot plant testing of ores with phosphonic acid collectors is complete cassiterite flotation at a pH below 4.0. In fundamental practice, it indicates that a pH region below 4 is the region of maximum flotation. However, in plant practice, at a low pH (below 4), loss of flotation occurred. The loss of flotation at a low pH has not been established. It is, however, postulated that loss of flotation is believed to be associated with complex solution chemical interaction between phosphonic acid collectors and cationic species, in particular, those of iron, which is always present in industrial flotation pulp. 

Sahoo, B., Sahu, S.K., Pramanik, P., 2011. A novel method for the immobilization of urease on phosphonate grafted iron oxide nanoparticle. J. Mol. Catal. B Enzym. 69, 95-102. 

Iron(III)-pyrophosphate looks promising as an alternative to iron(III)-carbohydrate preparations for parenteral administration for treatment of anemia.Kinetics of removal of iron from transferrin (tf) by pyrophosphate (pp) were found to be biphasic under certain conditions, with the rapid first phase attributed to the formation of a pp—Fe—tf—CO intermediate.A later study of the kinetics of removal of iron from transferrin employed pyrophosphate and tripodal phosphonates such as nitrilotris(methylenephosphonic acid), N(CH2P03H2)3. For the tripodal ligands there are parallel first-order and saturation pathways, with the latter dominant (contrast the exclusively first-order reaction of ferritin with nitrilotriacetate) for pyrophosphate the paths are roughly equal in importance. The saturation kinetics suggest that tfiFe-phosphonate intermediates play an important role in the kinetics. 

RNA hydrolysis, 45 285-287, 297-299 metalloenzymes, 45 251-252 bleomycin, 45 252-260, 299 nucleic acid hydrolysis metal ions and, 45 283-285 by oligonucleotide modified with metal complexes, 45 297-299 of phosphodiesters, 45 251, 287-297 by ribozymes, 45 285-287 cleavage by iron bleomycin, 43 140 polymerase, arsonomethyl phosphonate analogue, 44 201-202 substructures, 43 133-134 transfer... 

The irons selectivity in the Honier-Wniisworth-Fmnums reaction can he reversed by structural variation in the phosphonic ester moiety, the so called StilPGetmari variant. In this case tritluoro-substi-tuted ethoxy residues are introduced in the form of phosphonic ester 41, providing access to r/5 substituted acrylic esters. 

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