Hydrolysis of dicalcium phosphate dihydrate to hydroxyapatite
Rent the article at a discountRent now
* Final gross prices may vary according to local VAT.Get Access
Dicalcium phosphate dihydrate (DCPD) was hydrolysed in water and in 1 M Na2HPO4 solution at temperatures from 25–60°C. Hydrolysis was incomplete in water. At 25 °C, DCPD partially hydrolysed to hydroxyapatite (HAp). Formation of HAp is indicative of incongruent DCPD dissolution. At the higher temperatures, hydrolysis to HAp was more extensive and was accompanied by the formation of anhydrous dicalcium phosphate (DCP). Both of these processes are endothermic. When hydrolysis was carried out in 1 M Na2HPO4 solution, heat absorption was greater at any given temperature than for hydrolysis in water. Complete hydrolysis to HAp occurred in this solution. The hydrolysis of DCPD to HAp in sodium phosphate solution was also endothermic. The complete conversion of DCPD to HAp in sodium phosphate solution would not be expected if the only effect of this solution was to cause DCPD dissolution to become congruent. Because of the buffering capacity of a dibasic sodium phosphate solution, DCPD hydrolysed completely to HAp. Complete conversion to HAp was accompanied by the conversion of dibasic sodium phosphate to monobasic sodium phosphate. The formation of DCP was not observed indicating that the sodium phosphate solution precluded the DCPD-to-DCP dehydration reaction. In addition to affecting the extent of hydrolysis, reaction in the sodium phosphate solution also caused a morphological change in the HAp which formed. HAp formed by hydrolysis in water was needle-like to globular while that formed in the sodium phosphate solution exhibited a florette-like morphology. © 1998 Chapman & Hall
- W. E. Brown and L. W. Chow, in “Cements Research Progress — 1987” edited by P. W. Brown (American Ceramic Society, Westerville, OH, 1988) pp. 351-87.
- M. D. Francis and N. C. Webb, Calcif.Tissue Res. 6 (1971) 335.
- T. M. Gregory, E. G. Moreno and W. E. Brown, J. Res. NBS 74A (1970) 461.
- A. Perloff and A. S. Posner, Science 124 (1956) 583.
- P. W. Brown, J. Am. Ceram. Soc. 75 (1992) 17.
- K. Ishikawa and E. D. Eanes, J. Dent. Res. 72 (1993) 474.
- J. C. Elliott, “Structure and chemistry of the apatites and other calcium orthophosphates” (Elsevier, Amsterdam, 1994).
- M. S. Tung, L. C. Chow and W. E. Brown, 64 (1985).
- G. H. Nancollas and R. W. Marshall, ibid. 50 (1971) 1268.
- M. R. Christoffersen and J. Christoffersen, J. Cryst. Growth 87 (1988) 51.
- H. Mcdowell, T. M. Gregory and W. E. Brown, J. Res. NBS 81A (1977) 273.
- S. S. Feng and T. J. Rockett, J. Am. Ceram. Soc. 62 (1979) 619.
- M. Fulmer and P. W. Brown, J. Biomed. Mater. Res. 27 (1993) 1095.
- Idem., J. Mater. Res. 8 (1993) 1687.
- E. J. Prosen, P. W. Brown, F. L. Davies and G. Frohnsdorff, Cem. Concr. Res. 15 (1985) 703.
- K. S. Tenhuisen and P. W. Brown, J. Mater. Sci. Mater. Med. 7 (1996) 309.
- T. Ozawa, T. Ujiie and K. Tamuar, J. Chem. Soc. Jpn (1980) 1352.
- E. C. Moreno, T. M. Gregory and W. E. Brown, J. Res. NBS 70A (1966) 545.
- K. S. Tenhuisen and P. W. Brown, submitted.
- D. M. Roy, L. E. Drafall and R. Roy, in “Phase diagrams: materials science and technology”, edited by A. M. Alper (Academic Press, New York, 1978) pp. 185-239.
- Hydrolysis of dicalcium phosphate dihydrate to hydroxyapatite
Journal of Materials Science: Materials in Medicine
Volume 9, Issue 4 , pp 197-202
- Cover Date
- Print ISSN
- Online ISSN
- Kluwer Academic Publishers
- Additional Links
- Industry Sectors