Three phenylenediammonium sulfate (PDAS) salts were prepared under solvent free conditions and characterized by gravimetric,
spectroscopic and elemental analyses. Thermal decomposition studies of the salts have been investigated using TG (static air),
TG/DTG and DSC (inert atmosphere). The thermal decomposition pathways have also been suggested and it has been found that
PDAS salts on heating under vacuum in solid state give diaminobenzene sulfonic acids (DABSA) via proton transfer.
Six isomeric dimethyl anilinium bromides (DMABr) have been prepared and characterized by elemental and spectroscopic studies.
Thermal decomposition of these salts has been studied by TG and simultaneous TG-DTA techniques. Kinetic parameters have been
evaluated from isothermal TG data using contracting area and contracting cube equations. The decomposition pathways have also
been suggested which involves simultaneous sublimation (at lower temperature) and dissociative vaporization/decomposition
(at higher temperature).
Authors:G. Singh, I. P. S. Kapoor, and S. M. Mannan
Thermal and explosion characteristics of ring(mono) substituted arylammonium perchlorates (RSAP) are studied by DTA, impact and friction sensitivity measurements. Exothermic decomposition temperature (Td) from DTA curves and impact sensitivity data (h50%) were found to be linearly related to the Hammett substituent constant (σ+,σ−) andpKa values of the corresponding arylamines. A reaction scheme, based on the formation of reaction intermediates during decomposition and explosion, accounting for the products, is proposed which, involves proton transfer as the rate determining process and evolution of ammonia. It seems that oxidation-reduction reactions between the arylamine/substituted benzene and HClO4 or its decomposition products cause explosion.
Authors:G. Singh, I. Kapoor, J. Srivastava, and J. Kaur
Three dimethylanilinium sulfates (DMAS) have been prepared and characterised by elemental and spectral studies. Thermal decomposition of these salts has been studied by TG and simultaneous TG-DTG technique and kinetic parameters were evaluated from both dynamic and isothermal TG data using mechanism based kinetic equations. The thermal decomposition pathways have also been suggested and it has been found that DMAS salts give dimethyl aminobenzenesulfonic acids (DMABSA) via solid state reaction. The primary step in the thermal decomposition involves proton transfer followed by sulfonation.
Authors:G. Chartrand, S. F. Kapoor, D. R. Lick, and S. Schuster
For a graphG, the switched graphSv(G) ofG at a vertexv is the graph obtained fromG by deleting the edges ofG incident withv and adding the edges of
incident withv. Properties of graphs whereSv(G) ≅G or
are studied. This concept is extended to the partial complementSH(G) where H
. The investigation here centers around the existence of setsH for whichSH(G) ≅ G. A parameter is introduced which measures how near a graph is to being self-complementary.
Authors:G. Singh, B. Baranwal, I. Kapoor, D. Kumar, C. Singh, and R. Fröhlich
Three hexamethylenetetramine (HMTA) metal nitrate complexes such as [M(H2O)4(H2O-HMTA)2](NO3)·4H2O (where M=Co, Ni and Zn) have been prepared and characterized by X-ray crystallography. Their thermal decomposition have been studied
by using dynamic, isothermal thermogravimery (TG) and differential thermal analysis (DTA). Kinetics of thermal decomposition
was undertaken by applying model-fitting as well as isoconversional methods. The possible pathways of thermolysis have also
been proposed. Ignition delay measurements have been carried out to investigate the response of these complexes under condition
of rapid heating.