No abstract

The syntheses of Zn(II), Cd(II) and Cu(II) complexes of 2,5-bis{N-(2,6-diisopropylphenyl)iminomethyl}pyrrole (DIP(2)pyr)H 1 and their catalytic activities in CO(2) fixation are reported. The structures of these complexes were characterized by IR, (1)H, (13)C NMR and single crystal X-ray diffraction techniques. The catalytic activities of these complexes for the cycloaddition of CO(2) to an epoxide under one atmosphere of pressure and mild temperature conditions to yield cyclic carbonate have been studied. Among the four complexes synthesized, the Zn(II) and Cu(II) complexes were found to be versatile whereas the Cu(II) complex was more selective in the conversion. They were highly effective for the conversion of monosubstituted terminal epoxides, disubstituted terminal and internal epoxides to their corresponding cyclic carbonates with good to high yields.

Reduction of ZnCl2 using LiBH4 in mesitylene yielded zinc nanoparticles (Zn-NPs), borane (BH3) and closo-dodecaborate (B12H12)(2-). The BH3 evolved gas was trapped as Ph3P:BH3 adduct while closo-(B12H12)(2-) was extracted by methanol and characterized from spectral data.

No abstract

Hexamethyldisilazane assisted synthesis of Ag2S nanoparticles is demonstrated. Mechanistic studies revealed that Ag2S nanoparticles formed through S4N4 intermediates.

The reduction of aluminium trichloride by lithium aluminium hydride in the presence of poly(vinylpyrrolidone) or poly(methylmethacrylate) in mesitylene yielded nano aluminium particles in the matrices of respective polymers. Solution phase synthesis methodology was used successfully to produce composites of various Al/polymer ratios. The composites were characterized by powder XRD patterns and 27Al-NMR with MAS spectroscopic study. The method was useful to produce up to 10 g of nano aluminium that were pure and stable.

This study deals with the influence of nanosized titanium dioxide (TiO2) catalysts on the decomposition kinetics of ammonium nitrate (AN) and ammonium nitrate‐based composite solid propellant. TiO2 nanocatalyst with an average particle size of 10 nm was synthesized by sol‐gel method using titanium alkoxide as precursor. Formation of nanostructured TiO2 and presence of its anatase and brookite phases was confirmed by powder X‐ray diffraction (PXRD) and selected area diffraction (SAED) studies. Nano TiO2 was further characterized by transmission electron microscopy (TEM), infrared (IR) spectroscopy, and thermogravimetry. The catalytic effect of TiO2 nanocatalysts on the solid state thermal decomposition reaction of AN and nonaluminized HTPB/AN propellant was evaluated. To ascertain the effectiveness of the TiO2 nanocatalyst, the thermal kinetic constants for the catalytic and non‐catalytic decomposition of AN and AN propellant samples were computed by using a nonlinear integral isoconversional method. Catalytic influence was evident from the lowering of activation energy for the catalyzed decomposition reactions. Apparently, the nanocatalysts provide Lewis acid and/or active metal sites, facilitating the removal of AN dissociation products NH3 and HNO3 and thereby enhance the rate of decomposition. The changes in the critical temperature of thermal explosion of AN and AN propellant samples due to the addition of TiO2 nanocatalyst were also computed and the possible reasons for the changes are discussed.

No abstract