Ozonation of the pharmaceutical compound ranitidine: reactivity and kinetic aspects.
Ranitidine has been ozonated under different operating conditions of pH, applied ozone dose, initial ranitidine concentration and presence or absence of free radical inhibitors. Results of ranitidine evolution with time indicate a high reactivity of this compound with molecular ozone. Mineralization levels achieved in the order of 20-25% suggest that the (CH3)2-N-CH2- moiety bonded to the furan ring could be separated from the rest of the ranitidine structure and further mineralized. Only alkaline conditions (pH=11) are capable of increasing TOC conversion up to values close to 70%. Determination of the direct ozonation rate constant for ranitidine by means of competitive kinetics reveals an unacceptable dependence of the aforementioned constant with the reference compound reactivity. It is hypothesised that only reference compounds with reactivity similar to the target species should be used.
Rivas
Javier
J
Departamento de Ingeniería Química y Química Física, Facultad de Ciencias, Avenida de Elvas S/N, 06071 Badajoz, Spain. fjrivas@unex.es
Gimeno
Olga
O
Encinas
Angel
A
Beltrán
Fernando
F
D001667:Binding, Competitive; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008903:Minerals / Q000737:chemistry; D010126:Ozone / Q000737:chemistry*; D011899:Ranitidine / Q000737:chemistry* / Q000302:isolation & purification; D012996:Solutions; D014867:Water / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000737:chemistry* / Q000302:isolation & purification
D008903:Minerals; D012996:Solutions; D014874:Water Pollutants, Chemical; D014867:Water; D010126:Ozone; D011899:Ranitidine