Aluminum—citrate complexes

Interactions of Metal Salts with the Formation. Interactions of metal salts with the formation and distribution of the retained aluminum in a porous medium may significantly affect the location and strength of gels. This interaction was demonstrated with polyacrylamide-aluminum citrate gels [1514]. Solutions were displaced in silica sand. The major findings of this study are that as the aluminum-to-citrate ratio increases, the aluminum retention increases. Furthermore, the amount of aluminum retained by silica sand increases as the displacing rate decreases. The process is reversible, but the aluminum release rate is considerably slower than the retention rate. The amount of aluminum released is influenced by the type and the pH level of the flowing solution. The citrate ions are retained by silica sand primarily as a part of the aluminum citrate complex. Iron, cations, and some divalent cations cannot be used in the brine environment. 

D. Aluminum-Citrate Complexes Aluminum Toxicity and Iron Overload References... 

Lothenbach B, Furrer G, Schulin R (1997) Immobilization of heavy metals by polynuclear aluminum and montmorillonite compounds. Environ Sci Technol 31 1452-1462 Marklund E, Ohman L-O (1990) Equilibrium and structural studies of silicon(IV) and aluminum(III) in aqueous solution. 24 A potentiometric and Al NMR study of polynuclear aluminum(III) hydroxo complexes with lactic acid. Acta Chem Scand 44 228-234 Matzapetakis M, Raptopoulou CP, Terzis A, Lakatos A, Kiss T, Salifoglou A (1999) Synthesis, structural characterization, and solution behavior of the first mononuclear, aqueous aluminum citrate complex. Inorg Chem 38 618-619... 

A. (1998). Synthesis, structural characterization, and solution behavior of the first mononuclear, aqueous aluminum citrate complex. Inorg. Chem. 38, 618-619. 

Venturini, M., and Berthon, G. (1989). Aluminum speciation studies in biological fluids, 2 Quantitative investigations of aluminum-citrate complexes and appraisal of their potential significance in vivo. J. Inorg. Biochem. 31, 69-90. 

Another way to slow substitution is to covalently bond a ligand to silica— compare bonding ligands to monoclonal antibodies above. Oxine bound to silica reacts much more slowly with Al, for example, than when it is in solution. Another example of slow substitution at Al is related to the indium chemistry mentioned above, involving its slow transfer from its transferrin complex by reaction with iron(III)-citrate to form the much more stable combination of iron-transferrin and aluminum-citrate complexes. Further examples of slow substitution kinetics involving ferritin will be found in the iron(III) section (Section 8.3.4). 

Mak MKS, Langford CH (1983) Kinetic analysis applied to aluminum citrate complex. Inorg Chim Acta 70 237-246... 

Keizer TS, Scott BE, Sauer NN, McCleskey TM (2005) Stable soluble beryllium aluminum citrate complexes inspired by the emerald mineral structures. Angew Chem Int Ed 44 2403 2406... 

Iron(III) citrate, " " or iron(III) ammonium citrate, is the usual vehicle for administering supplementary iron to an iron-deficient patient, for inducing iron-overload in rats or other creatures prior to testing the efficacy of iron chelators, or for introducing the isotope Fe for metabolic tracer studies. Stability constants for the aqueous iron(III)-citrate system have been established. " The 2 1 complex is claimed to be the dominant species in iron(III)/citrate/DMF systems. " There has been a very qualitative study of the incorporation of iron into transferrin from iron citrate. " Iron(III) citrate reacts relatively slowly with the aluminum(III)-transferrin complex to give the thermodynamically strongly favored combination of iron(III)-transferrin with aluminum(lll) citrate. " The mechanism of iron uptake from citrate complexes in cells has been briefly discussed. An octa-iron citrate complex appears in Section 5.4.5.4.3 below. 

Weberg and Berstad 1986 Yokel and McNamara 1988). The effect has been shown with a variety of aluminum compounds and several forms of citrate in both experimental and clinical studies. The combination of citrate and aluminum has been responsible for a number of deaths in uremic patients, and the clinical implications of the interaction has led some investigators to advise against concomitant exposure to aluminum and citrate in any form (e.g., antacids and orange juice), especially to patients with impaired renal function. As discussed in Sections 2.3.1.2 and 2.4.1, citrate complexes with aluminum to form a species that is particularly bioavailable in the near-neutral pH conditions of the intestines. 

Figure 4. The stracture of the aluminum citrate trimeric complex (Feng et al. 1990). There are no bridging hydroxyls and a single bound water molecule.

Feng TL, Gurian PL, Healy MD, Barron AR (1990) Aluminum citrate isolation and stractural characterization of a stable trinuclear complex. Inorg Chem 29 408-411 Fitzgerald JJ, Rosenberg AH (1999) Chemistry of aluminum chlorohydrate and activated aluminum chlorohydrate. In Antiperspirants and Deodorants, 2nd edition. Laden K (ed) Marcel Dekker, New York, p 83-136... 

Bodor, A., Bdnyai, L, and Tdth, 1. (2002). H- and C-NMR as tools to study aluminum coordination chemistry aqueous Al(ni)-citrate complexes. Coord. Chem. Rev. 228. 175-186. 

Eeng, T. L., Gurian, P. L.. Healy, M. D.. and Barron, A. R. (1990). Aluminum citrate isolation and structural characterization of a stable trinuclear complex. Inorg. Chem. 29, 408-411. 

Matzapetakis, M., Kourgiantakis, M.. Dakanali, M., Raptopoulou, C. P., Terzis, A., Lakatos, A., Kiss, T., Banyai, L, lordanidis, L., Mavromoustakos, T., and Salifoglou, A. (2001). Synthesis, pH-dependent structural characterization, and solution behavior of aqueous aluminum and gallium citrate complexes. Inorg. Chem. 40, 1734-1744. 

Citrate. Cadariu, Goina, and Oniciu (4) report an inflection in the titration curve of an aluminum-citrate solution with hydroxyl ions at pH 11-12. This inflection diminishes as the ratio of citrate to aluminum increases, and disappears at citr./Al = 5. The complex acid formed at... 

Aluminum, chloro hydroxy propylene glycol complexes Aluminum, chloro propylene glycol complexes. See Aluminum chlorohydrex Aluminum, chlorotetrahydroxy ((2-hydroxy-5-oxo-2-imidazolin-4-yl) ureato) di-. See Alcloxa Aluminum citrate... 

Profile modification is a process in which flooding water is diverted from highly permeable zones into less permeable oil-bearing layers within a subterranean reservoir. In recent years this has been achieved by the use of polymeric hydrogels in Y ich the water-soluble polymer is cross-linked by a multivalent metal ion". The latter may be generated in situ from a redox couple, e.g., sodium dichromate/sodium metabisulfite or as a complexed reagent, e.g., aluminum citrate. This enables the gelation process to be retarded until the aqueous polymer solution has been placed deep into the thief zone. 

Twenty-two different metal Ions have been shown to crosslink water-soluble polysaccharides . Water-soluble synthetic polymers can also be crosslinked by several types of metal Ions. This section will briefly summarize the state of knowledge regarding general aspects of metal ion crosslinked gels. Then, the most common EOR gel systems of this type, aluminum citrate, chromium redox, complexed chromium, and chromlum/blopolymer, will be described In detail. 

The form of the citrate complex Is not well known. Models of complexes with a 1 1 Al cltrate ratio have been proposed, but It remains to be determined why solutions of aluminum citrate with greater ratios are stable. ... 

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