http://nopr.niscair.res.in/handle/123456789/2073 Search the Channel search http://nopr.niscair.res.in/simple-search http://nopr.niscair.res.in/handle/123456789/2199 Title: Sorption behaviour of D 155 resin for Ce(III) <br/> <br/>Authors: Xiong, Chunhua <br/> <br/>Abstract: The sorption of Ce(III) by D155 resin is reported here. The effect of pH on the sorption of Ce(III), the sorption capacity of the resin, the isotherms, kinetics and thermodynamics have been investigated by the sorption-desorption method. The sorption mechanism is also proposed. The sorption is spontaneous and endothermic under the examined conditions. <br/> <br/>Page(s): 1377-1380 Fri, 29 Aug 2008 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/2198 Title: Kinetics and mechanism of oxidation of some thioacids by morpholinium chlorochromate <br/> <br/>Authors: Malani, N; Pohani, S; Baghmar, M; Sharma, Pradeep K <br/> <br/>Abstract: Oxidation of thioglycollic, thiolactic and thiomalic acids by morpholinium chlorochromate is first order both in MCC and thioacids. The reaction is catalysed by hydrogen ions. The hydrogen ion dependence takes the form kobs=a+b [H⁺]. Oxidation of the thiolactic acid has been studied in nineteen different organic solvents. The solvent effect has been analysed by using Kamlet’s and Swain’s multiparametric equations. A mechanism involving the formation of a thioester and its decomposition in slow step is also proposed. <br/> <br/>Page(s): 1373-1376 Fri, 29 Aug 2008 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/2147 Title: Micellar effects on dye sensitized photooxidation of phenothiazine <br/> <br/>Authors: Kathuria, Shipra; Gupta, P K; Dhamiwal, N R <br/> <br/>Abstract: Methylene blue sensitized photooxidation of phenothiazine (PTH) in sodium dodecylsulphate, cetyl trimethylammonium bromide and brij-35 in methanol-water, ethanol-water and acetonitrile-water gives phenothiazine-3-one (PTN) and phenothiazine sulphoxide as the products at low conversion. A small shift in the λmax indicates the formation of an additional product, which is destroyed during the separation. An inverse relationship between log Φ (Φ= quantum yield of PTN formation) and 1/Є₀ (Є₀ = dielectric constant of the medium) supports the participation of singlet oxygen (¹O₂) at low [PTH]. A mechanism consistent with the results showing the participation of ¹O₂ at low [PTH] and electron transfer-exciplex formation at high [PTH] is postulated. The formation of phenothiazine sulphoxide has been suggested to be through the phenothiazinyl radical. <br/> <br/>Page(s): 1384-1388 Fri, 29 Aug 2008 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/2146 Title: 2-Hydroxy-1-naphthaldehyde-p-hydroxybenzoic hydrazone as a spectropho-tometric reagent for the determination of lanthanum (III) <br/> <br/>Authors: Chowdary, P Govinda; Reddy, K P P R Mohan; Reddy, V Krishna; Reddy, P Raveendra <br/> <br/>Abstract: A new chromophore, 2-hydroxy-1-naphthaldehyde-p-hydroxybenzoic hydrazone has been used for the determination of lanthanum (III). The reagent reacts with lanthanum (III) in aque-ous dimethyl formamide in wide pH range forming brownish yellow coloured 2:3 (M:L) soluble complex with max at 415 nm. The colour intensity further increases in the cetyl trimethyl am-monium bromide micellar medium (0.1%) at room temperature. Beer’s law is obeyed in the range 0.277-8.334 μg mL⁻¹ and 0.008-2.639 μg mL⁻¹ of La(III) in direct and derivative methods, respectively. The molar absorptivity, Sandell’s sensitivity, detec-tion limit, determination limit and relative standard deviation are found to be: 2.3810⁴ L mol⁻¹ cm⁻¹, 0.006 μg cm⁻², 0.035 μg mL⁻¹, 0.106 μg mL⁻¹ and 0.42%, respectively. The second order derivative spectrophotometric method developed for the determi-nation of lanthanum (III) shows greater sensitivity and selectivity. The proposed direct and derivative methods are applied for the determination of lanthanum in standard lanthanum samples. <br/> <br/>Page(s): 1381-1383 Fri, 29 Aug 2008 22:58:59 GMT