Osmium [VIH]-catalyzed oxidation of indoles by potassium hexacyanoferrate [III] in alkaline media: a kinetic and mechanistic study

The reaction of indoles with Os [VIII] catalyzed hexacyanoferrate [III] in alkaline media to produce the corresponding oxindole has been studied at constant temperature and ionic strength. The reaction followed first order kinetics with respect to [indole], [OH[-] and [Os [VIII]], fractional order in [Fe[CN][6][-3]. The effects of added electrolytes, potassium hexacyanoferrate [II], relative permitivity and temperature have also been studied. A mechanism consistent with the kinetic data is proposed. Furthermore, the structural influence of the indoles on the reactivity has been discussed

Kinetics and mechanism of the oxidation of indoles by alkaline potassium hexacyanoferrate [III]

The reaction of indoles with hexacyanoferrate [III] in alkaline media to produce the corresponding oxindole has been studied at constant temperature and ionic strength. The reaction followed first order kinetics with respect to [indole] and [OH[-], whereas fractional order with respect to [Fe[CN][6][-3]] was found. The effects of added electrolytes, potassium hexacyanoferrate [II], relative permitivity and temperature have also been studied. On the basis of experimental observations, a probable reaction mechanism has been proposed

Preparation and characterization of some phosphoborosilicate glasses containing some micronutrients as plant fertilizers

Four phosphoborosilicate glasses containing one or more of the micronutrients: namely Cu, Zn, Fe, were prepared using analytical grade chemicals by melting in an electric furnace at about 1400°C for 2hr. The melts being calcined at about 450°C, were carefully crushed to grains of 2mm size. The release rate of the glass grains of 2mm size in 0.4%HC1 solution, 2% citric acid solution, and distilled water at room temperature was determined using a standard grain method for immersion time intervals varying between 1 to 4 weeks. The concentrations of K and P ions released into the leaching solutions were determined. The results obtained revealed that some of the prepared plant fertilizer samples led to a significant increase in the plant growth better than that observed in case of the traditional fertilizers. Furthermore, the extents of K and P ions released increased by increasing the time of immersion

Density and molar volume of some high lead silicate glasses

Density measurements and molar volume calculations of some high lead silicate glasses were studied with the view to throw some light on the structure of these glasses. All glasses were melted in an electrically heated furnace at a temperature ranging from 1100 to 1200° for four hours. After complete melting, each molten glass was poured on an iron marver and was then annealed at the appropriate temperature. The experimental results obtained could be correlated to many factors such as the nature of the lead ion itself and also to the field strengths and ionic radii and volume of the different incorporated cations

Density, molar volume and thermal conductivity of some lead borate glasses

Studies on the density, molar volume and thermal conductivity of some glasses containing high proportions of lead oxide, were carried out. All glasses were melted in an electrically heated furnace at 1100 degree for 4 hours, depending on the glass composition. The amount of the molten glass was 100 g in each case. After complete melting, the molten glass was annealed at the appropriate temperatures and tests for the obtained results showed that the value of density increased while the value of the molar volume decreased with the gradual increase of the lead oxide content. In the glasses containing either one of R2O, RO, R2O3, or RO2, the value of density decreased while the value of the molar volume increased with the gradual increase of the mono, di, tri or tetravalent metal oxides, respectively. The results obtained from thermal conductivity, are also given and correlated to the nature of the lead ion among several factor such as the polarization, field strengths and ionic radii of the incorporated cations

Mechanism of anodic dissolution of lead in sodium hydroxide solutions

The potential of the lead anode was measured at a function of current density in 0.1 -1 ON NaOH solutions at 20 -50 degree. The over-potential is independent of pH in pure solutions as well as in solutions containing excess neutral salts. From the electron number [4], it was suggested that the surface lead atoms exist as diatomic molecules. A suboxide [Pb2O] is first formed, which undergoes self-oxidation to PbO. This latter step governs the overall reaction rate. The effect of temperature was also investigated. The exchange current is slightly affected with temperature