sodium-hypochlorite and potassium-bromide

The reaction of polycyclic aromatic hydrocarbons (PAHs) previously adsorbed on silica gel or diatomaceous earth with sodium hypochlorite was carried out to elucidate their reactivity to aqueous chlorine. It was demonstrated that the PAHs adsorbed on silica reacted more rapidly than the PAHs themselves in water, leading to the formation of many chlorinated and oxidized derivatives. A similar reaction in the presence of potassium bromide was found to preferentially produce corresponding brominated derivatives. These reactions seem to proceed through PAHs adsorbed on the silica surface and halogenating agents, the electrophilicity of which may be raised by the catalytic effect of the silanol group of the silica surface. These findings from the environmental viewpoint suggest that the reaction of hydrophobic compounds adsorbed on sediment cannot be neglected.

Topics: Adsorption; Bromides; Chlorine; Environmental Pollutants; Gas Chromatography-Mass Spectrometry; Kinetics; Molecular Structure; Polycyclic Aromatic Hydrocarbons; Potassium Compounds; Silicon Dioxide; Sodium Hypochlorite

Addition of solid Ca(OCl)(2) as the terminal oxidant in the TEMPO-mediated selective oxidation has the benefit of easier operation. A variety of partially protected saccharide derivatives (1a-l) have been successfully converted into the corresponding uronate derivatives, including disaccharide building blocks for GAG fragments and precursors to saponins. The beneficial effect of Aliquat 336 was also disclosed in the oxidation of certain substrates.

Topics: Bromides; Calcium Compounds; Carbohydrate Conformation; Carbohydrate Sequence; Chromatography; Cyclic N-Oxides; Models, Chemical; Molecular Sequence Data; Oxygen; Potassium Compounds; Saponins; Sodium Hypochlorite; Time Factors; Uronic Acids; Water