Authors:M. Kamruddin, P. K. Ajikumar, S. Dash, R. Krishnan, A. K. Tyagi, and K. Krishan
A facility based on real time multiple ion detection trend analysis mass spectrometry has been set up in our laboratory for studying thermal decomposition behaviour of inorganic solids. The system has been used for studying decomposition of CuSO4· 5H2O. Non-isothermal kinetic rate expressions based on random nucleation and 3-d phase boundary migration (for dehydration stage), 3-d diffusion and 3-d phase boundary migration (for decomposition stage) were found to have significant correlations with Evolved Gas Analysis (EGA) data. Brief description of the experimental facility along with physical explanations behind compliance of EGA data to above models are discussed.
Authors:N. N. Das, P. K. Satapathy, S. C. Dash, and P. Mohanty
A new CrIII–Schiff base complex of N,N′-ethylene-bis-salicylamide (Salm), supported on acidic alumina, was characterized by chemical and spectral (UV–Vis-DRS and FT-IR) analyses. The comparative catalytic activity of the neat and supported metal complex was evaluated using H2O2 decomposition as the model reaction at varying H2O2 concentration and amount of catalyst which showed a higher activity for the supported metal complex. A preliminary study showed that the supported CrIII(Salm) was also active for the oxidation of phenol using H2O2 as oxidant leading to catechol (selectivity ∼62%) and hydroquinone (selectivity ∼32%) as the major products.
Authors:P. Mishra, V. Chakra Vortty, K. Dash, N. Das, and S. Bhattacharyya
Presence of thiocyanate ions results in appreciable extraction of Zr(IV) by Aliquat 336 from low aqueous HCl acidities, i.e., 0.1 to 4.5M. The variation of concentrations of HCl, thiocyanate and Aliquat 336 greatly influences the extent of extraction. Mixtures of Aliquat 336 and TOPO result in synergistic extraction of Zr and Hf from acidic thiocyanate media, the extracted species being the disolvate with TOPO. By controlled adjustment of HCl, SCN– and Aliquat 336 concentrations, separation of Zr, Nb and Hf is possible. A maximum separation factor (DNb/DZr) of 3675 has been achieved under certain conditions.