178273-91-1Relevant academic research and scientific papers
Photocatalytic oxidation of pirimicarb in aqueous slurries containing binary and ternary oxides of zinc and titanium
Fenoll, Jos,Garrido, Isabel,Helln, Pilar,Flores, Pilar,Vela, Nuria,Navarro, Simn
, p. 24 - 32 (2014)
The photocatalytic degradation of pirimicarb in pure water has been studied using zinc oxide (ZnO), titanium dioxide (TiO2) and zinc titanates (Zn2TiO4 and ZnTiO3) under artificial light (300-460 nm) irradiation. Comparison of catalysts showed that TiO2 is the most efficient for the removal of pirimicarb and their transformation products. To obtain a better understanding of the mechanistic details of these ZnO-TiO2-assisted photodegradation of pirimicarb, the transformation products of the processes were identified by liquid chromatography tandem mass spectrometry (LC-MS2) and liquid chromatography time of flight mass spectrometry (LC-TOF/MS) techniques. The probable photodegradation pathways are proposed and discussed. The main steps involved: N-dealkylation of the 2-dimethylamino group to form the carbamate and decarbamoylation of the carbamate moiety with further N-dealkylation of the 2-dimethylamino group to have the hydroxypyrimidines.
Photodegradation of Pesticides. Photolysis Rates and Half-Life of Pirimicarb and Its Metabolites in Reactions in Water and in Solid Phase
Pirisi, Filippo M.,Cabras, Paolo,Garau, V. Luigi,Melis, Marinella,Secchi, Enrico
, p. 2417 - 2422 (1996)
The photodegradation of Pirimicarb under three different artificial lights and sunlight was studied in water solutions (buffers pH 5, 6, and 7) and in solid phase. Five photocompounds were formed in solution and two in solid phase. Pirimicarb undergoes fast degradation under all conditions. In buffer solutions it first gave three compounds with a kinetic parallel process. These compounds were assigned the structures of 2-[(methylformyl)amino]-5,6-dimethylpyrimidin-4-yl dimethylcarbamate (II), 2-(methylamino)-5,6-dimethylpyrimidin-4-yl dimethylcarbamate (III), and 2-(dimethylamino)-5,6-dimethyl-4-hydroxypyrimidine (V). V and II were stable to further photolysis (the latter with t1/2 = 849 h) whereas III undergoes further degradation to 2-amino-5,6-dimethylpyrimidin-4-yl dimethylcarbamate (IV), and to 2-(formylamino)-5,6-dimethylpyrimidin-4-yl dimethylcarbamate (IX). Both compounds were photodegraded to undetectable species, and IX shows a very high t1/2 (48 h). A different behavior was found in solid phase, and only II and III were formed. A kinetic parallel process was demonstrated. The environmental t1/2 and t1/100 calculated for Pirimicarb and its photoproducts suggest their reduced persistence in natural waters.
