Fluorapatite, synthesis

Synthetic fluor-containing apatites are prepared and investigated for biomedical applications and serve also as models to understand the formation of biological fluorapatites and some of their properties. The synthesis of fluoridated apatites has been accomplished in various ways from simple ion exchange in solution to more elaborate techniques involving sol-gel routes or thermal processes. Two main classes of synthesis routes are presented in this chapter high-temperature routes and low-temperature solution routes. 

Finally, control of fluorapatite particle size (from 15 nm to 200 pm) and morphology can be achieved by varying precipitation conditions using aqueous precipitation from a micro-emulsion or by biomimetic synthesis in a gelatin matrix [129],... 

H. Chen, K. Sun, Z. Tang, R.V. Law, J.F. Mansfield, A. Czajka-Jakubowska, B.H. Clarkson, Synthesis of fluorapatite nanorods and nanowires by direct precipitation from solution. Crystal Gro wth and Design 6 (2006) 1504-1508. 

S. Ben Abdelkader, I. Khattech, C. Rey, M. Jemal, Synthesis, characterization and thermochemistry of calcium-magnesium hydroxyapatite and fluorapatite, Thermochim. Acta 376 (2001) 25-36. 

G. Montel, Synthesis and decomposition reactions of fluorapatite involving liberation of fluorides of phosphorus, Colloq. Sek. Anorg. Chem. Intern. Union Reineu. Angew. Chem. Munster (1955) 178-183. 

L.M. Rodriguez-Lorenzo, J.N. Hart, K.A. Gross, Influence of fluorine in the synthesis of apatites. Synthesis of solid solutions of hydroxy-fluorapatite. Biomaterials 24 (2003) 3777-3785. 

R. Fabian, L. Kotsis, P. Halmos, E. Vszprem, H. Veszprem, Synthesis of fluorapatite by using solid phase reactions, Epitoanyag 52 (2000) 2-7. 

The methods of synthesis of fluorapatite have been widely dis cussed (J ). It is for example possible to obtain fluorapatite by substituting the hydroxyl ion for the fluoride ion, either in a-queous solution at room temperature, or through a solid state reaction at 800°C. It can also be prepared by the action of 6-tricalcium phosphate on calcium fluoride at about 800°C. Its solubility and thermal stability have already been established. While much is known about fluorapatite, many questions still exist concerning the mechanism of their formation, their composition and the structure of some of them. Two of these problems are dealt with here. First, we discuss the formation mechanism of fluorapatite by a solid state reaction between calcium fluoride and apa-titic tricalcium phosphate. Then we present the preparation and the structure of a carbonated apatite rich in fluoride ions. 

Rosseeva EV, Buder J, Simon P, Schwarz U, Frank-Kamenetskaya OV, Kniep R (2008) Synthesis, characterization, and morphogenesis of carbonated fluorapatite-gelatine nanocomposites a complex biomimetic approach toward the mineralization of hard tissues. Chem Mater 20(19) 6003-6013... 

Kniep R, Simon P (2007) Fluorapatite-Gelatine-Nanocomposites Self-Organized Morphogenesis, Real Structure and Relations to Natural Hard Materials. 270 73-125 Koenig BW (2007) Residual Dipolar Couplings Report on the Active Conformation of Rhodopsin-Bound Protein Fragments. 272 187-216 Komatsu K (2005) The Mechanochemical Solid-State Reaction of Fullerenes. 254 185-206 Kremsner JM, Stadler A, Kappe CO (2006) The Scale-Up of Microwave-Assisted Organic Synthesis. 266 233-278... 

Ito A, Aoki H, Akao M, Mima N, Otsuka R, Tsutsumi S (1988) Stractme of borate groups in borate-contairring apatite. J Ceram Soc Japan 96 695-697 Ivanova TI, Frank-Kamenetskaya OV, KoFtsov V, Ugolkov L (2001) Crystal stracture of calcirrm-deficient carbonated hydroxyapatite. Thermal decomposition. J Solid State Chem 160 340-349 Jahnke RA (1984) The synthesis and solubility of carborrate fluorapatite. Am J Sci 284 58-78... 

Jahnke RA (1984) The synthesis and solubility of carbonate fluorapatite. Am J Sci 284 58-78 Jarosewich E, Nelen JA, Norberg JA (1980) Reference samples for electron microprobe analysis. Geostandards Newsletter 4 43-47... 

Ben Abdelkader S, Khattech I, Rey C, Jemal M (2001) Synthesis, characterization and thermochenustiy of calcium-magnesium hydroxylapatite and fluorapatite. Thermochim Acta 376 25-36 Bender SA, Bumgardner JD, Roach MD, Bessho K, Ong JL (2000) Effect of protein on the dissolution of HA coatings. Biomaterials 21 299-305... 

Cheng K, Shen G, Weng WJ, Han GR, Ferreira JMF, Yang J (2001) Synthesis of hydroxyl-apatite/fluorapatite solid solution by a sol-gel method. Mater Lett 51 37-41 Chemg AM, Chow LC, Takagi S (2001) In vitro evaluation of a calcium phosphate cement root canal filler/sealer. J Endodontics 27 613-615... 

Kantam, M. L., Venkanna, G. T., S. Kumar, K. B., Balasuhrahmanyam, V., and Bhargava, S. 2009b. Synthesis of benzoxazoles via intramolecular cychzation of orf/io-halobenzani-lides using copper fluorapatite catalyst. Synlett. (11) 1753-1756. 

Nikcevic, I., Jokanovic, V., Mitric, M., Nedic, Z., Makovec, D. and Uskokovic, D. (2004) Mechanochemical synthesis of nanostructured fluorapatite/ fluorhydroxyapatite and carbonated fluorapatite/fluorhydroxyapatite. 

SCHEME 4.139 Synthesis of a-hydroxyphosphonates from aldehydes using sodium-modified fluorapatite [232]. 

The use of sodium-modified fluorapatite for the synthesis of a-hydroxyphosphonates has been reported (Schemes 4.139 and 4.140) [232]. For the reaction between secondary phosphites and aldehydes, the reaction conditions were quite mild, and excellent yields of the targets were obtained within a few minutes under solvent-free conditions using... 

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