Extraction of uranium(IV) and uranium(VI) by primary and tertiary-amines from sulphate solutions

In developing a method for possible low level isotopic enrichment, which uses to advantage the equilibrium isotope effect observed during U(1V)-U(VI) electron exchange reaction in sulphate solutions, details of a solvent extraction process involving high concentration of a mixture of U(IV) and U(VI) and at low acid concentrations, are described. The extraction behaviour of uranium under these conditions is discussed. During the extraction with amines, U(IV) tended to get oxidised in sulphate solutions.     

Analyses of carcinogenic aromatic amines released from harmful azo colorants by Streptomyces SP. SS07

Extracellular fluid protein (ECFP) of Streptomyces species SS07 has been used to reduce water soluble azo dyes and the carcinogenic amines released have been compared with that from chemical reduction. The effect of temperature, pH and contact time on the recovery of amines using ECFP was studied. The ECFP releases carcinogenic amines at a pH of 9.2 and a temperature of 37 degrees C for a contact period of 24 h. The reduction products were analyzed with HPLC and their structures confirmed by LC-MS and GC-MS. It was observed that both the ECFP and chemical reduction methods released similar type of amine products. In the case of dye samples, compared to chemical reduction, 5-20% increase in the release of carcinogenic amines by ECFP was observed. The percentage of amine products released by chemical reduction was higher for leather garment samples compared to ECFP treatment.     

Separation of xylidine isomers by micellar electrokinetic chromatography

Xylidines are important precursors for the production of dyes, drugs, and various other products. Because of the high carcinogenic nature of some xylidine isomers it becomes very essential and relevant to develop suitable analytical procedures to separate isomers as well as enhance detection at very low concentrations. Micellar electrokinetic chromatography has been standardized at various influencing parameters such as pH, ionic strength, and micelle modifiers, and the optimum conditions have been ascertained for the best separation and sensitivity of standard mixtures. The applicability of the procedure in environmental samples is studied.     

Electron irradiation studies on ammonium molybdophosphate

Ammonium molybdophosphate (AMP) was irradiated with electrons up to a dose of 1 MGy. X-ray diffraction patterns and FT-IR of irradiated and control AMP samples were recorded. Uptake of¹³⁷Cs from nitric acid in the range of 0.2 to 10 mol·dm^–3 was estimated by a batch equilibration technique. AMP undergoes perceptible changes in its physico-chemical characteristics on irradiation with electrons. Uptake of¹³⁷Cs from nitric acid by irradiated AMP was nearly the same as the control AMP in the nitric acid concentration range of 6 to 10 mol·dm^–3 and relatively higher in the range of 0.2 to 6 mol·dm^–3. The results are discussed in terms of available information on the physicochemical properties of 12-heteropoly acids and their salts.     

A class of solvable coupled nonlinear oscillators with amplitude independent frequencies

Existence of amplitude independent frequencies of oscillation is an unusual property for a nonlinear oscillator. We find that a class of N coupled nonlinear Liénard type oscillators exhibit this interesting property. We show that a specific subset can be explicitly solved from which we demonstrate the existence of periodic and quasiperiodic solutions. Another set of N coupled nonlinear oscillators, possessing the amplitude independent nature of frequencies, is almost integrable in the sense that the system can be reduced to a single nonautonomous first order scalar differential equation which can be easily integrated numerically.     

Barium Manganate Oxidation in Organic Synthesis: Part—IV: Oxidation of Aldehydes to Carboxylic Acids

The oxidation of aldehydes to corresponding carboxylic acids by barium manganate under heterogeneous conditions is described. Aromatic aldehydes were smoothly converted to carboxylic acids while aliphatic aldehydes underwent polymerisation.     

Barium Manganate Oxidation in Organic Synthesis: Part III: Oxidation of Schiff'S Bases to Benzimidazoles Benzoxazoles and Benzthiazoles

The oxidative cyclisation of bsenzylideneamino anilines, phenols and thiophenols to benzimidazoles, benzoxazoles and benzthiazoles respectively using barium manganate is described.     

Bi(NO3)3.5H2O: A Convenient Reagent for Selective Oxidation of Sulfides to Sulfoxides

Bi(NO₃)₃.5H₂O, a cheaply available, crystalline solid has been found to readily effect selective oxidation of a variety of sulfides to sulfoxides in acetic acid medium at room temperature in fair to good yields.