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Bhattacharyya S.,Defense R and D Establishment | Hatua K.,Bengal Engineering and Science University
RSC Advances | Year: 2014

The present DFT investigation supports a previous conclusion of Dean et al. that hydroxylation occurs without epoxide intermediate at room temperature due to a strong electrostatic interaction of peroxide ions with π electrons of CC bonds of chalcone, and 3-hydroxyflavone has been found to be the major product. The calculated activation energy difference (ΔG#) of initial enolization followed by hydroxylation or simultaneous cyclization and hydroxylation has been found to be negligible (∼4 kcal mol-1). On the other hand, epoxide formation requires significant activation energy, which is supposed to occur at high temperatures. In addition, if epoxide is formed, the ring opens by an attack of phenolic oxygen, occurring preferentially at α position via a five-member transition state due to a low activation barrier height (19.82 kcal mol-1 in the gas phase and 19.55 kcal mol-1 in ethanol) compared to that of a six-member transition state (44.41 kcal mol-1 at B3LYP in the gas phase and 38.55 kcal mol -1 in ethanol). It is also observed that the solvation study does not affect the main conclusion of the paper. These findings also support the previous observation of Dean et al. Predicted ΔG# in different DFT functionals are consistent, although the total energy is significantly different. © 2014 the Partner Organisations. Source

Mahato T.H.,Defense R and D Establishment | Singh B.,Defense R and D Establishment | Srivastava A.K.,Defense R and D Establishment | Prasad G.K.,Defense R and D Establishment | And 3 more authors.
Journal of Hazardous Materials | Year: 2011

Present study investigates the potential of CuO nanoparticles calcined at different temperature for the decontamination of persistent chemical warfare agent sulphur mustard (HD) at room temperature (30 ± 2°C). Nanoparticles were synthesized by precipitation method and characterized by using SEM, EDAX, XRD, and Raman Spectroscopy. Synthesized nanoparticles were tested as destructive adsorbents for the degradation of HD. Reactions were monitored by GC-FID technique and the reaction products characterized by GC-MS. It was observed that the rate of degradation of HD decreases with the increase in calcination temperature and there is a change in the percentage of product of HD degradation. GC-MS data indicated that the elimination product increases with increase in calcination temperature whereas the hydrolysis product decreases. © 2011 Elsevier B.V. Source

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