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Effect of Reaction Time and Heat Treatment in the Production of Hydroxyapatite by Hydrothermal Synthesis

Kati Nida, Ozan Sermin, Yildiz Tülay, Arslan Mehmet

Archives of Metallurgy and Materials

2022

Vol. 67, iss. 4

1427--1434

In the present work, Hydroxyapatite synthesis was carried out using hydrothermal method with calcium nitrate tetrahydrate (Ca(NO3)2.4H2O) and fosfor pentaoksit (P2O5) as precursors. For the hydrothermal method, constant reaction temperature (180°C) and different reaction times (6 hours, 12 hours, 18 hours and 24 hours) were determined. The samples produced were divided into two groups. Four samples were not heat treatment; four samples were heat treatment at 700°C for 1 hour. The obtained products were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) techniques, X-ray diffraction (XRD) and UV-Vis spectrometer. SEM photos showed that the Hydroxyapatite powders produced are in the form of the agglomerate. According to EDS results, Hydroxyapatite samples are of high purity. XRD’s findings confirm that the diffraction peaks correspond to the pure phase of Hydroxyapatite. A general decrease was observed in the energy band gap of the samples with increasing hydrothermal reaction time.

Microwave assisted synthesis, spectral studies and antimicrobial activities of some 2′,4′-difluorophenyl chalcones

Vijayakumar S., Arulkumaran R., Sundararajan R., Sakthinathan S. P., Suresh R., Kamalakkannan D., Ranganathan K., Sathiyamoorthy K., Mala V., Vanangamudi G., Thirunarayanan G.

International Letters of Chemistry, Physics and Astronomy

2013

Vol. 9, iss. 1

68-86

Some 2′,4′-difluorophenyl chalcones have been synthesized under microwave irradiation using aldol condensation between 2,4-difluoroacetophenone and substituted benzaldehydes using catalytic amount of hydroxyapatite. The yields of the chalcones are more than 85 %. The purities of these synthesized chalcones were examined by their physical constants and spectroscopic data. The UV absorption maxima (λmax, nm), infrared stretches (ν, cm-1) of CO, fingerprint region of CHip/op, CH=CHop, C=Cop modes, NMR chemical shifts (δ, ppm) of vinyl proton, carbon and carbonyl carbons have been assigned and correlated with Hammett substituent constants, F and R parameters using single and multi-regression analysis. From the statistical analysis the effect of substituent on the above spectral frequencies can be discussed. The antimicrobial activities of these synthesized chalcones have been screened using Bauer-Kirby method.