Synthesis of octacalcium phosphate (OCP) by hydrolysis of brushite was studied using a 3 block central composite design including 4 factors and 6 responses. Analysis of the responses allowed the definition of one set of experimental conditions in which OCP was obtained with the highest overall desirability (87.6 %).

The hydrolytic conversion of a solid amorphous calcium phosphate of empirical formula Ca9(PO4)6 to a poorly crystalline apatitic phase, under conditions where Ca2+ and PO4 3− were conserved, was studied by means of solid-state magic-angle sample spinning31P-NMR (nuclear magnetic resonance). Results showed a gradual decrease in hydrated amorphous calcium phosphate and the formation of two new PO4 3−-containing components: an apatitic component similar to poorly crystalline hydroxyapatite and a protonated PO4 3−, probably HPO4 2− in a dicalcium phosphate dihydrate (DCPD) brushite-like configuration. This latter component resembles the brushite-like HPO4 2− component previously observed by31P-NMR in apatitic calcium phosphates of biological origin. Results were consistent with previous studies by Heughebaert and Montel [18] of the kinetics of the conversion of amorphous calcium phosphate to hydroxyapatite under the same conditions.

Le diagramme de phases du système Ca3(PO4)2-CaO-CaSO4 a été étudié principalement par ATG-ATD couplées, radiocristallographie et analyse chimique. En tenant compte de la decomposition de CaSO4, deux invariants ternaires ont été mis en évidence. Le premier est un eutectique ternaire à 1250°C liq ϵ → Ca3(PO4)2 + CaSO4 + Ca4P2O9 le second correspond à une peritexie transitoire à 1280 ° C CaO + liq π → Ca4P2O9 + CaSO4 Aucune phase nouvelle n'est observée dans le système ternaire.

Dans les conditions précisées dans le texte, et à 100 °C, les orthophosphates précipités en présence d’ions Mg2+ et Ca2+ peuvent être soit du type apatitique quand la concentration en magnésium total est < 0,1 mM soit du type whitlockite, quand la concentration en magnésium total est > 0,2 mM. Il n’a pas été possible de montrer avec certitude la substitution d’ions Ca2+ par des ions Mg2+ dans le réseau de l’apatite. La teneur en ions magnésium absorbée par l’apatite croît avec la teneur en ions magnésium dans la solution et atteint une limite pondérale voisine de 0,54 %. La teneur en ions magnésium dans la whitlockite étudiée est constante et correspond à : Ca18Mg2H2 (PO4)14.

Two fractional factorial designs were used for the investigation of the synthesis of 5-hydroxymethyl-2-furancarboxaldehyde from d -fructose. The reaction system selected combines an ion-exchanger, used as a catalyst, with an extracting solvent which is not miscible with the aqueous phase containing the sugar, and affords mild operating conditions. The main effect of seven parameters and their interactions on four responses of the reaction system were quantified. An orientation for the optimization of the conversion rate to HMF as well as of the reaction selectivity can thus be proposed.

Chemischer InformationsdienstVolume 7, Issue 3 Physical Inorganic Chemistry ChemInform Abstract: SYNTHESIS, OPTICAL PROPERTIES, AND ESR STUDY OF MANGANESE(2+) ION-DOPED CALCIUM FLUORAPATITE SINGLE CRYSTALS WITH LOW DEFECT CONTENT JEAN-CLAUDE HEUGHEBAERT, JEAN-CLAUDE HEUGHEBAERTSearch for more papers by this authorJOCELYN SERIOT, JOCELYN SERIOTSearch for more papers by this authorBENJAMIN JOUKOFF, BENJAMIN JOUKOFFSearch for more papers by this authorFRANCOISE GAUME-MAHN, FRANCOISE GAUME-MAHNSearch for more papers by this authorGERARD MONTEL, GERARD MONTELSearch for more papers by this author JEAN-CLAUDE HEUGHEBAERT, JEAN-CLAUDE HEUGHEBAERTSearch for more papers by this authorJOCELYN SERIOT, JOCELYN SERIOTSearch for more papers by this authorBENJAMIN JOUKOFF, BENJAMIN JOUKOFFSearch for more papers by this authorFRANCOISE GAUME-MAHN, FRANCOISE GAUME-MAHNSearch for more papers by this authorGERARD MONTEL, GERARD MONTELSearch for more papers by this author First published: January 20, 1976 https://doi.org/10.1002/chin.197603006Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume7, Issue3January 20, 1976 RelatedInformation

Chemischer InformationsdienstVolume 7, Issue 15 Preparative Inorganic Chemistry ChemInform Abstract: LOCALIZATION OF MANGANESE(2+) IONS IN SYNTHETIC CALCIUM FLUOROAPATITES PREPARED BY VARIOUS CHEMICAL REACTIONS TORABALI BARATALI, TORABALI BARATALISearch for more papers by this authorJEAN-CLAUDE HEUGHEBAERT, JEAN-CLAUDE HEUGHEBAERTSearch for more papers by this authorJOCELYN SERIOT, JOCELYN SERIOTSearch for more papers by this authorGERARD MONTEL, GERARD MONTELSearch for more papers by this author TORABALI BARATALI, TORABALI BARATALISearch for more papers by this authorJEAN-CLAUDE HEUGHEBAERT, JEAN-CLAUDE HEUGHEBAERTSearch for more papers by this authorJOCELYN SERIOT, JOCELYN SERIOTSearch for more papers by this authorGERARD MONTEL, GERARD MONTELSearch for more papers by this author First published: April 13, 1976 https://doi.org/10.1002/chin.197615029AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume7, Issue15April 13, 1976 RelatedInformation