2 resultados para m-phenoxybenzaldehyde
Resumo:
With addition of methanol in acetic acid solvent, m-phenoxytoluene could be oxidized to m-phenoxybenzaldehyde selectively by a cobalt bromide catalyst. Paratemters such as the ratio of Co/Br and the reaction time of m-phenoxytoluene oxidation as well as visible spectra of cobalt bromide in acetic acid/methanol solvents, were also investigated. Addition of methanol caused the oxidation of aldehydes to proceed more slowly than it did solely in acetic acid solvent. The decrease of cobaltous-multibromides in acetic acid/methanol solvents was responsible for the improvement in the selective oxidation of m-phenoxytoluene. (C) 1999 Elsevier Science B.V. All rights reserved.
Resumo:
The impact of pyretroids, their by-products and degradation products on humans and the environment is recognized as a serious problem. Despite several studies regarding esfenvalerate toxicity and its detection in water and sediments, there is still a lack of information about its degradation intermediates and by-products in water. In this work, an HPLC method was developed to follow up the degradation of esfenvalerate and to detect the intermediates and by-products formed during the chemical degradation process. The chemical degradation was performed using an esfenvalerate suspension and different concentrations of hydrogen peroxide, temperatures, and pH. The reaction was monitored for 24 hr, and during the kinetic experiments, samples were collected at several reaction times and analyzed by HPLC-UV-PAD. In the degradation process, eleven different compounds (intermediate and by-products) were detected, among them the metabolites 3-phenoxybenzoic acid and 3-phenoxybenzaldehyde. HPLC-UV-PAD proved to be a valuable analytical technique for the rapid and reliable separation and determination of esfenvalerate, its degradation intermediates, and by-products.
