Correction: Graphene oxide–TiO₂ composite: an efficient heterogeneous catalyst for the green synthesis of pyrazoles and pyridines

Correction for ‘Graphene oxide–TiO2 composite: an efficient heterogeneous catalyst for the green synthesis of pyrazoles and pyridines’ by Shweta Kumari et al., New J. Chem., 2016, 40, 5053–5060.</p

Synthesis and characterization of a Cu(<scp>ii</scp>) Schiff base complex immobilized on graphene oxide and its catalytic application in the green synthesis of propargylamines

A Cu(ii) Schiff base complex immobilized on graphene oxide has been synthesized and characterized by FTIR, FT-RAMAN, XRD, UV, TEM, FE-SEM, EDAX, TGA, N2 adsorption–desorption and AAS analysis.</p

Graphene oxide supported MnO₂ nanorods: an efficient heterogeneous catalyst for oxidation of aromatic amines to azo-compounds

Graphene oxide supported MnO2 nanorods (GOnc), a composite material, has been synthesized and characterized by XRD, FE-SEM, EDX, BET surface area measurement, FTIR and Raman Spectroscopy.</p

Rheokinetic Analysis of Hydroxy Terminated Polybutadiene Based Solid Propellant Slurry

The cure kinetics of propellant slurry based on hydroxy-terminated polybutadiene (HTPB) and toluene diisocyanate (TDI) polyurethane reaction has been studied by viscosity build up method. The viscosity (ɳ)–time (t) plots conform to the exponential function ɳ = aebt, where a & b are empirical constants. The rate constants (k) for viscosity build up at various shear rate (rpm), evaluated from the slope of dɳ/dt versus ɳ plots at different temperatures, were found to vary from 0.0032 to 0.0052 min-1. It was observed that the increasing shear rate did not have significant effect on the reaction rate constants for viscosity build up of the propellant slurry. The activation energy (Eɳ), calculated from the Arrhenius plots, was found to be 13.17±1.78 kJ mole-1, whereas the activation enthalpy (∆Hɳ*) and entropy (∆Sɳ*) of the propellant slurry, calculated from Eyring relationship, were found to be 10.48±1.78 kJ mole-1 and –258.51± 5.38 J mole-1K-1, respectively. The reaction quenching temperature of the propellant slurry was found to be -9 ° C, based upon the experimental data. This opens up an avenue for a “freeze-and-store”, then “warm-up and cast”, mode of manufacturing of very large solid rocket propellant grains

Synthesis and crystal structures of salen-type Cu(II) and Ni(II) Schiff base complexes : application in [3+2]-cycloaddition and A3-coupling reactions

The synthesis of two new salen-type Schiff base complexes of the type [Cu(L)]·0.5H2O, 1, and [Ni(L)], 2, from the reaction of a 6,6′-[(1E,1′E)-(cyclohexane-1,2-diylbis(azanylylidene))bis(methanylylidene)bis(3-(diethylamino)phenol)] salen-type Schiff base ligand (H2L) with Cu(OAc)2·H2O and Ni(OAc)2·4H2O in methanol at room temperature, respectively, is described. The complexes are isolated as coloured crystalline solids and characterized by elemental analysis, FT-IR spectroscopy, UV-visible spectroscopy and single crystal X-ray diffraction studies. The paramagnetic nature of complex 1, having giso = 2.076, was confirmed by EPR studies, which indicated a distorted square planar geometry of the complex. In contrast to this, the nickel complex was found to be diamagnetic in nature and it was additionally characterized by 1H NMR. The crystal structures of complexes 1 and 2 confirm the distorted square planar geometry of both the complexes. Complex 1 was found to be a better catalyst for the synthesis of a series of 5-substituted 1H-tetrazoles from nitriles and sodium azide via [3+2]-cycloaddition and for the A3-coupling reaction of aldehydes, secondary amines and terminal alkynes with a low catalyst loading (0.7 and 0.9 mol%, respectively) as compared to complex 2. Complex 1 is novel in the sense that, being a homogeneous catalyst, it can be recovered almost quantitatively in both reactions and recycled up to four times to afford good yields of the corresponding products