ABSTRACT
H/D exchange reactions can be observed by NMR spectroscopy of acebutolol (ACE). The results obtained showed deuterium incorporation at α-posi t ion of the carbonyl group of acebutolol, when using deuterium oxide or deuterated methanol as deuterium source and solvent. The spontaneous deuteration is proceeded by the following pathway CH3âCH2DâCHDâCD3, through a keto-enol tautomerization reaction. Furthermore, LC-MS / QTOF analyses have confirmed the proposed H/D exchange. In order to reduce the time of total deuteration observed at the acetyl group alkaline catalysts were employed.
Subject(s)
Acebutolol , Hydrogen , Deuterium/chemistry , Deuterium Oxide/chemistry , Hydrogen/chemistry , Methanol , SolventsABSTRACT
The photocatalytic degradation of a macrolide (tylosin) has been studied using immobilized titanium dioxide as photocatalyst in a laboratory reactor under UV illumination (365 nm). The degradation of the antibiotic and of the reaction intermediary product was monitored by UV spectrophotometry and HPLC. Three photocatalysts (P25 from Degussa and PC105 and PC500 from Millennium) immobilized on glass plates were compared. A slightly better degradation was obtained with P25. Then the tylosin degradation kinetics were investigated with the P25 photocatalyst. The kinetic model of Langmuir-Hinshelwood is satisfactorily obeyed at initial time and in the course of the reaction. Adsorption and apparent rate constants were determined. These results suggest that, although an intermediary by-product was detected during the reaction, complete degradation of tylosin can be achieved, which confirms the feasibility of such a photocatalytic treatment for tylosin elimination from wastewater.
Subject(s)
Anti-Bacterial Agents/chemistry , Photolysis , Tylosin/chemistry , Water Pollutants, Chemical/chemistry , Water/chemistry , Kinetics , Molecular StructureABSTRACT
Natural antique colorants include mainly red pigments such as cinnabar and ochre. These archeological pigments were used especially as funeral and cosmetic makeup and are a material proof of handicraft activities and exchanges. The identification and characterization of a group of punic colorants, corresponding to samples discovered during excavations at several Tunisian archeological sites (Cartage, Ksour Essef, Kerkouane, Bekalta, Makthar, Bou Arada), were conducted using the least destructive analysis techniques such us scanning electron microscopy coupled to X-ray fluorescence microprobe, direct current plasma emission spectroscopy, atomic absorption spectrometry, Fourier transform infrared spectrometry and X-ray diffraction. Eleven natural red colorants from punic period were subject to this investigation and were compared to contemporary substances. Five colorants were cinnabar and the other six were ochre.
