Kinetics of Chromic Acid Oxidation of Thioglycollic, Thiolactic & Thiomalic Acids

1082-108

Hydroxylation and mechanistic studies of α, β-unsaturated compounds with alkaline hexacyanoferrate (III)

798-801The reactions of three α, β-unsaturated compounds of the type CH2=CHX (where X = -CN, -CONH2 and -C02 -) with alkaline hexacyanoferrate (III) have been studied. The reactions take place according to the rate expression, d[Fe(CN)63-]  / dt = k [Fe(CN)63-) (CH2=CHX] (OH-). The values of k at 318K are 7.2 x 10-4,4.45 X 10-4 and 3.2 x 10-4 (dm6mol-2s-1) in the oxidations of the respective substrates. The oxidation rates follow the order: -CN> -CONH2 > -C02  The substrates are oxidized to give diols under kinetic conditions. Tentative reaction mechanism leading to the formation of oxidation products has been suggested

Oxidative behaviours and relative reactivities of some aliphatic, heterocyclic and aromatic aldehydes towards bis(dihydrogentellurato )cuprate(III) and argentate(III) in alkaline medium

190-196The oxidative behaviours and relative reactivities of some aliphatic aldehydes, XCHO (where X = H - , Me - , MeCH2 -, Me2CH-), 2-furaldehyde and aromatic aldehydes, YC6H4CHO (where Y= -H, -NO2, -Cl and -OMe) towards bis(dihydrogentellurato)metallate(III) ion (where MIlI= CUllI or AgIII) in alkaline medium have been investigated. The reactions are first order each in [aldehyde] and [MIII(H2TeO6)2]5- - but the rate is independent of [OH-]. The values of kobs in the oxidation of some aliphatic aldehydes, 2-furaldehyde and benzaldehyde in aqueous medium follow the order: Me2CH - > MeCH2 - > Me - > H - > C4H3O - > C6H5, -. The electron withdrawing substituents facilitate the rate of oxidation of benzaldehyde whereas electron donating substituents have opposite effect and the values of kobs, follow the order: - NO2 > - H > - Cl > - OMe. The pseudofirst order rate constants decrease considerably in benzaldehyde-d1., than benzaldehyde under comparable condition of experiments. Irrespective of whether the substrate is aliphatic or aromatic, the oxidation reactions occur via free radical mechanism although the substituent and isotope effects in the oxidations of aromatic aldehydes indicate that C - H bond cleavage via proton transfer may also occur. The activation parameters of the reactions have been determined and the mechanism of the reactions is discussed

Kinetics & Mechanism of Oxidation of -Glucopyranose l-Phosphate by Chromium(VI) & Vanadium(V) in Perchloric Acid Medium

23-2

Bane to boon: tailored defect induced bright red luminescence from cuprous iodide nanophosphors for on-demand rare-earth-free energy-saving lighting applications

The long standing controversy concerning the defect band in cuprous iodide (CuI) has been addressed in this paper from a technological point of view of its solid state lighting application. Recently, solid state lighting technology using nanophosphors has been proposed as the prime candidate in the energy saving lighting paradigm. Herein, we demonstrate a novel rare-earth free and non-toxic CuI nanophosphor, which has been synthesized via a facile solvothermal route. These nanophosphors are able to show ultra-bright and stable red emission under near UV excitation. The spectral features of this easily derived nanophosphor are not less than any rare-earth or cadmium based conventional phosphor. Furthermore, it has been conclusively verified that the deep red emission is strongly related to the excess iodine induced optimized defect level engineering in the band structure. The concepts and results presented in this paper clearly establish that the CuI nanophosphor is a promising 'green' material for the state-ofthe-art rare-earth free lighting and display applications